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Sample records for abundance high temperature

  1. Element Abundances in High-temperature Solar Flare Plasma from MESSENGER SAX Observations

    NASA Astrophysics Data System (ADS)

    Dennis, Brian R.; Nittler, Larry R.; Phillips, Kenneth; Schwartz, Richard A.; Starr, Richard D.; Tolbert, Anne K

    2014-06-01

    X-ray spectral measurements of many solar flares made with the MESSENGER SAX instrument have been used to determine the abundances of Fe, Ca, Ar, S, and Si in the high temperature plasma. All available data from launch in 2004 to date have been used to obtain spectral fits to the SAX data from 2.3 to 8.5 keV for all time intervals with a detectable count rate in the Fe-line complex at 6.7 keV. For each time interval, OSPEX, our object-oriented IDL spectral analysis program, is used to obtain values of the emission measure, temperature distribution, and abundances that give the best-fit of the corresponding CHIANTI photon spectrum folded through the instrument response matrix to the measured count-rate spectrum above background. Distributions will be presented of element abundances for each flare and for all flares detected during each year of observations. Variations in measured abundances will be discussed as to whether they reflect real differences from the mean or differences due to statistical and/or systematic uncertainties. Comparisons will be made with abundance measurements made from other data sets, in particular by Phillips and Dennis (2012) using data from the Ramaty High Energy Solar Spectroscopic Imager (RHESSI), and by Warren et al. (2013) using data from the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO).Phillips, K. J. H. and Dennis, B. R., “The Solar Flare Iron Abundance,” 2012, ApJ, 748, 52.Warren, H. “Measurements of Absolute Abundances in Solar Flares,” 2013, arXiv, 2013arXiv1310.4765W

  2. Methanethiol abundance in high-temperature hydrothermal fluids from the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Reeves, E.; Seewald, J. S.; Saccocia, P.; van der Meer, M.

    2008-12-01

    The formation of aqueous organic sulfur compounds in hydrothermal systems remains poorly constrained, despite their potential significance in 'prebiotic' chemistry and the origin of life. The simplest - methanethiol (CH3SH) - has been implicated as a critical abiogenic precursor to the establishment of primitive microbial metabolism in early Earth hydrothermal settings. It also represents a readily-utilized substrate for microbial sulfate-reducing communities and a potential intermediate species in abiotic CH4 formation. To assess the abundance of CH3SH and factors regulating its stability under hydrothermal conditions we measured CH3SH concentrations in a suite of hydrothermal fluids collected from the Rainbow, Lucky Strike, TAG and Lost City hydrothermal sites located on the Mid-Atlantic Ridge. Fluids were collected using isobaric gas-tight samplers and analyzed for CH3SH by shipboard purge-and-trap gas chromatography. Measured concentrations at Rainbow (1.2 -- 223nM), Lucky Strike (1.1 -- 26nM), TAG (8.5 -- 11nM) and Lost City (1.6 -- 3.0nM) are all substantially lower than predicted for thermodynamic equilibrium with CO2, H2 and H2S at measured vent conditions. The highest concentrations (91 -- 223nM), however, were observed at Rainbow in intermediate temperature (128 -- 175°C) H2-rich fluids that may have undergone conductive cooling. Increased concentrations with decreasing temperature is consistent with the thermodynamic drive for the formation from CO2, suggesting a possible abiotic origin for CH3SH in some fluids. Substantially lower concentrations in the low temperature fluids at Lost City are consistent with the extremely low levels of CO2 and H2S in these fluids. Other possible sources of CH3SH to vent fluids must be considered, however, and include thermal alteration of biomass present in low-temperature environments and microbial consortia that produce CH3SH as a byproduct of anaerobic methane oxidation. Current models for the emergence of primordial

  3. Nontoxic and abundant copper zinc tin sulfide nanocrystals for potential high-temperature thermoelectric energy harvesting.

    PubMed

    Yang, Haoran; Jauregui, Luis A; Zhang, Genqiang; Chen, Yong P; Wu, Yue

    2012-02-01

    Improving energy/fuel efficiency by converting waste heat into electricity using thermoelectric materials is of great interest due to its simplicity and reliability. However, many thermoelectric materials are composed of either toxic or scarce elements. Here, we report the experimental realization of using nontoxic and abundant copper zinc tin sulfide (CZTS) nanocrystals for potential thermoelectric applications. The CZTS nanocrystals can be synthesized in large quantities from solution phase reaction and compressed into robust bulk pellets through spark plasma sintering and hot press while still maintaining nanoscale grain size inside. Electrical and thermal measurements have been performed from 300 to 700 K to understand the electron and phonon transports. Extra copper doping during the nanocrystal synthesis introduces a significant improvement in the performance.

  4. Highly siderophile element (HSE) abundances in the mantle of Mars are due to core formation at high pressure and temperature

    NASA Astrophysics Data System (ADS)

    Righter, K.; Danielson, L. R.; Pando, K. M.; Williams, J.; Humayun, M.; Hervig, R. L.; Sharp, T. G.

    2015-04-01

    Highly siderophile elements (HSEs) can be used to understand accretion and core formation in differentiated bodies, due to their strong affinity for FeNi metal and sulfides. Coupling experimental studies of metal-silicate partitioning with analyses of HSE contents of Martian meteorites can thus offer important constraints on the early history of Mars. Here, we report new metal-silicate partitioning data for the PGEs and Au and Re across a wide range of pressure and temperature space, with three series designed to complement existing experimental data sets for HSE. The first series examines temperature effects for D(HSE) in two metallic liquid compositions—C-bearing and C-free. The second series examines temperature effects for D(Re) in FeO-bearing silicate melts and FeNi-rich alloys. The third series presents the first systematic study of high pressure and temperature effects for D(Au). We then combine our data with previously published partitioning data to derive predictive expressions for metal-silicate partitioning of the HSE, which are subsequently used to calculate HSE concentrations of the Martian mantle during continuous accretion of Mars. Our results show that at midmantle depths in an early magma ocean (equivalent to approximately 14 GPa, 2100 °C), the HSE contents of the silicate fraction are similar to those observed in the Martian meteorite suite. This is in concert with previous studies on moderately siderophile elements. We then consider model calculations that examine the role of melting, fractional crystallization, and sulfide saturation/undersaturation in establishing the range of HSE contents in Martian meteorites derived from melting of the postcore formation mantle. The core formation modeling indicates that the HSE contents can be established by metal-silicate equilibrium early in the history of Mars, thus obviating the need for a late veneer for HSE, and by extension volatile siderophile elements, or volatiles in general.

  5. Distribution of Prokaryotic Abundance and Microbial Nutrient Cycling Across a High-Alpine Altitudinal Gradient in the Austrian Central Alps is Affected by Vegetation, Temperature, and Soil Nutrients.

    PubMed

    Hofmann, Katrin; Lamprecht, Andrea; Pauli, Harald; Illmer, Paul

    2016-10-01

    Studies of the altitudinal distributions of soil microorganisms are rare or have led to contradictory results. Therefore, we studied archaeal and bacterial abundance and microbial-mediated activities across an altitudinal gradient (2700 to 3500 m) on the southwestern slope of Mt. Schrankogel (Central Alps, Austria). Sampling sites distributed over the alpine (2700 to 2900 m), the alpine-nival (3000 to 3100 m), and the nival altitudinal belts (3200 to 3500 m), which are populated by characteristic plant assemblages. Bacterial and archaeal abundances were measured via quantitative real-time PCR (qPCR). Moreover, microbial biomass C, microbial activity (dehydrogenase), and enzymes involved in carbon (CM-cellulase), nitrogen (protease), phosphorus (alkaline phosphatase), and sulfur (arylsulfatase) cycling were determined. Abundances, microbial biomass C, and activities almost linearly decreased along the gradient. Archaeal abundance experienced a sharper decrease, thus pointing to pronounced sensitivity toward environmental harshness. Additionally, abundance and activities were significantly higher in soils of the alpine belt compared with those of the nival belt, whereas the alpine-nival ecotone represented a transitional area with intermediate values, thus highlighting the importance of vegetation. Archaeal abundance along the gradient was significantly related to soil temperature only, whereas bacterial abundance was significantly related to temperature and dissolved organic carbon (DOC). Soil carbon and nitrogen concentrations explained most of the variance in enzyme activities involved in the cycling of C, N, P, and S. Increasing temperature could therefore increase the abundances and activities of microorganisms either directly or indirectly via expansion of alpine vegetation to higher altitudes and increased plant cover. PMID:27401822

  6. The abundance of a single domain cyclophilin in Solanaceae is regulated as a function of organ type and high temperature and not by other environmental constraints.

    PubMed

    Kiełbowicz-Matuk, Agnieszka; Rey, Pascal; Rorat, Tadeusz

    2007-11-01

    The abundance of a single domain cyclophilin (CyP), designated as SsCyP, was investigated in Solanum sogarandinum and Solanum tuberosum plants during development and in response to various environmental constraints. We show that under control conditions, SsCyP is distributed throughout the plant but in an organ-specific manner. In both Solanum species, the highest protein levels are observed in transporting organs and in tubers, and substantial amounts are noticed in open flowers and in stamens. We also show that the SsCyP abundance in leaves strongly decreases with age. In in vitro-grown plantlets of S. sogarandinum, the SsCyP gene is induced by low temperature at the transcript level but not at the protein level, indicating that post-transcriptional mechanisms control SsCyP expression under cold conditions. In in vivo-grown Solanum plants, the organ-dependent SsCyP protein distribution and abundance are not modified by cold, drought, salinity and photooxidative treatments. In contrast, the protein abundance substantially decreases in all organs of Solanum plants subjected to heat shock. We conclude that the SsCyP protein acts mainly during development and does not belong to the group of stress-induced CyPs.

  7. Temperature-associated dynamics of songbird winter distributions and abundances.

    PubMed

    Butler, J Russell; MacMynowski, Dena P; Laurent, Chad; Root, Terry L

    2007-12-01

    Using Christmas Bird Count data, we analyze the annual spatio-temporal abundances of six passerine species in the upper Great Plains, US (1960-1990). This study provides new insight into how global warming could cause separation of species within present-day communities. We find that winter relative abundances of similarly-sized songbirds are differentially affected by ambient winter temperature. As such, average annual winter temperature fluctuations (i.e., severity of winter) are significantly (P < 0.05) correlated with the relative abundances of three species while the other three are not. Our conditional probability-of-occurrence analysis indicates that the abundances of the three temperature-associated species declined markedly below -4 degrees C while the abundances of the other three species fluctuated little from 8 degrees C to -16 degrees C. We conclude that even in colder climates i) the winter distributions of some, but not all, songbirds are directly or indirectly limited by temperature; and ii) these birds have dynamic abundances that can quickly respond to temperature changes.

  8. The temperatures, abundances and gravities of F dwarf stars.

    NASA Technical Reports Server (NTRS)

    Bell, R. A.

    1971-01-01

    Theoretical colors computed from laboratory line data and from model stellar atmospheres have been used to interpret the colors of about 150 F and early G dwarfs. Effective temperatures have been derived from the H-beta index and from R-I, abundances have been obtained from m(sub 1) and from b-y, and gravities have been obtained from c(sub 1) and from b-y. The effective temperatures and gravities are in good agreement with values obtained from spectral scans. Absolute magnitudes have been obtained from the effective temperatures and gravities, the latter being used with assumed stellar masses to yield radii. The present results provide theoretical justification of the empirical formulas given by Crawford and by Stroemgren for the determination of absolute magnitudes and abundances from uvby photometry.

  9. High Abundance of Ions in Cosmic Ices

    NASA Technical Reports Server (NTRS)

    Gudipati, Murthy S.; Allamandola, Louis J.; Fonda, Mark (Technical Monitor)

    2002-01-01

    Water-rich, mixed molecular ices and polycyclic aromatic hydrocarbons (PAHs) are common throughout interstellar molecular clouds and the Solar System. Vacuum ultraviolet (VUV) irradiation and particle bombardment of these abiotic ices produces complex organic species, including important biogenic molecules such as amino acids and functionalized PAHs which may have played a role in the origin of life. This ability of such water-rich, oxygen dominated ices to promote production of complex organic species is surprising and points to an important, unusual, but previously overlooked mechanism at play within the ice. Here we report the nature of this mechanism using electronic spectroscopy. VUV-irradiation of PAH/H2O ices leads to an unprecedented and efficient (greater than 70 %) conversion of the neutral PAHs to their cation form (PAH+). Further, these H2O/PAH+ ices are stabile at temperatures below 50 K, a temperature domain common throughout interstellar clouds and the Solar System. Between 50 and 125 K they react to form the complex organics. In view of this, we conclude that charged PAHs and other molecular ions should be common and abundant in many cosmic ices. The chemical, spectroscopic and physical properties of these ion-rich ices can be of fundamental importance for objects as diverse as comets, planets, and molecular clouds and may account for several poorly understood phenomena associated with each of these object classes.

  10. A TEMPERATURE AND ABUNDANCE RETRIEVAL METHOD FOR EXOPLANET ATMOSPHERES

    SciTech Connect

    Madhusudhan, N.; Seager, S.

    2009-12-10

    We present a new method to retrieve molecular abundances and temperature profiles from exoplanet atmosphere photometry and spectroscopy. We run millions of one-dimensional (1D) atmosphere models in order to cover the large range of allowed parameter space. In order to run such a large number of models, we have developed a parametric pressure-temperature (P-T) profile coupled with line-by-line radiative transfer, hydrostatic equilibrium, and energy balance, along with prescriptions for non-equilibrium molecular composition and energy redistribution. The major difference from traditional 1D radiative transfer models is the parametric P-T profile, which essentially means adopting energy balance only at the top of the atmosphere and not in each layer. We see the parametric P-T model as a parallel approach to the traditional exoplanet atmosphere models that rely on several free parameters to encompass unknown absorbers and energy redistribution. The parametric P-T profile captures the basic physical features of temperature structures in planetary atmospheres (including temperature inversions), and fits a wide range of published P-T profiles, including those of solar system planets. We apply our temperature and abundance retrieval method to the atmospheres of two transiting exoplanets, HD 189733b and HD 209458b, which have the best Spitzer and Hubble Space Telescope data available. For HD 189733b, we find efficient day-night redistribution of energy in the atmosphere, and molecular abundance constraints confirming the presence of H{sub 2}O, CO, CH{sub 4}, and CO{sub 2}. For HD 209458b, we confirm and constrain the dayside thermal inversion in an average 1D temperature profile. We also report independent detections of H{sub 2}O, CO, CH{sub 4}, and CO{sub 2} on the dayside of HD 209458b, based on six-channel Spitzer photometry. We report constraints for HD 189733b due to individual data sets separately; a few key observations are variable in different data sets at similar

  11. TOWARD A REMOVAL OF TEMPERATURE DEPENDENCIES FROM ABUNDANCE DETERMINATIONS: NGC 628

    SciTech Connect

    Croxall, Kevin V.; Smith, J. D.; Pellegrini, E.; Brandl, B. R.; Groves, B. A.; Kreckel, K.; Sandstrom, K. M.; Walter, F.; Schinnerer, E.; Kennicutt, R. C.; Galametz, M.; Johnson, B. D.; Armus, L.; Beirão, P.; Calzetti, D.; Dale, D. A.; Hinz, J. L.; Hunt, L. K.; Koda, J.

    2013-11-10

    The metal content of a galaxy, a key property for distinguishing between viable galaxy evolutionary scenarios, strongly influences many of the physical processes in the interstellar medium. An absolute and robust determination of extragalactic metallicities is essential in constraining models of chemical enrichment and chemical evolution. Current gas-phase abundance determinations, however, from optical fine-structure lines are uncertain to 0.8 dex as conversion of these optical line fluxes to abundances is strongly dependent on the electron temperature of the ionized gas. In contrast, the far-infrared (far-IR) emission lines can be used to derive an O{sup ++} abundance that is relatively insensitive to temperature, while the ratio of the optical to far-IR lines provides a consistent temperature to be used in the derivation of an O{sup +} abundance. We present observations of the [O III] 88 μm fine-structure line in NGC 628 that were obtained as part of the Key Insights on Nearby Galaxies: a Far Infared Survey with Herschel program. These data are combined with optical integrated field unit data to derive oxygen abundances for seven H II regions. We find the abundance of these regions to all lie between the high and low values of strong-line calibrations and to be in agreement with estimates that assume temperature fluctuations are present in the H II regions.

  12. Contrasting effects of temperature and precipitation change on amphibian phenology, abundance and performance.

    PubMed

    Ficetola, Gentile Francesco; Maiorano, Luigi

    2016-07-01

    Climate change is determining a generalized phenological advancement, and amphibians are among the taxa showing the strongest phenological responsiveness to warming temperatures. Amphibians are strongly influenced by climate change, but we do not have a clear picture of how climate influences important parameters of amphibian populations, such as abundance, survival, breeding success and morphology. Furthermore, the relative impact of temperature and precipitation change remains underappreciated. We used Bayesian meta-analysis and meta-regression to quantify the impact of temperature and precipitation change on amphibian phenology, abundance, individual features and performance. We obtained effect sizes from studies performed in five continents. Temperature increase was the major driver of phenological advancement, while the impact of precipitation on phenology was weak. Conversely, population dynamics was mostly determined by precipitation: negative trends were associated with drying regimes. The impact of precipitation on abundance was particularly strong in tropical areas, while the importance of temperature was feeble. Both temperature and precipitation influenced parameters representing breeding performance, morphology, developmental rate and survival, but the response was highly heterogeneous among species. For instance, warming temperature increased body size in some species, and decreased size in others. Similarly, rainy periods increased survival of some species and reduced the survival of others. Our study showed contrasting impacts of temperature and precipitation changes on amphibian populations. Both climatic parameters strongly influenced amphibian performance, but temperature was the major determinant of the phenological changes, while precipitation had the major role on population dynamics, with alarming declines associated with drying trends.

  13. Temperature affects microbial abundance, activity and interactions in anaerobic digestion.

    PubMed

    Lin, Qiang; De Vrieze, Jo; Li, Jiabao; Li, Xiangzhen

    2016-06-01

    Temperature is a major factor determining the performance of the anaerobic digestion process. The microbial abundance, activity and interactional networks were investigated under a temperature gradient from 25°C to 55°C through amplicon sequencing, using 16S ribosomal RNA and 16S rRNA gene-based approaches. Comparative analysis of past accumulative elements presented by 16S rRNA gene-based analysis, and the in-situ conditions presented by 16S rRNA-based analysis, provided new insights concerning the identification of microbial functional roles and interactions. The daily methane production and total biogas production increased with temperature up to 50°C, but decreased at 55°C. Increased methanogenesis and hydrolysis at 50°C were main factors causing higher methane production which was also closely related with more well-defined methanogenic and/or related modules with comprehensive interactions and increased functional orderliness referred to more microorganisms participating in interactions. This research demonstrated the importance of evaluating functional roles and interactions of microbial community. PMID:26970926

  14. High temperature furnace

    DOEpatents

    Borkowski, Casimer J.

    1976-08-03

    A high temperature furnace for use above 2000.degree.C is provided that features fast initial heating and low power consumption at the operating temperature. The cathode is initially heated by joule heating followed by electron emission heating at the operating temperature. The cathode is designed for routine large temperature excursions without being subjected to high thermal stresses. A further characteristic of the device is the elimination of any ceramic components from the high temperature zone of the furnace.

  15. High temperature reactors

    NASA Astrophysics Data System (ADS)

    Dulera, I. V.; Sinha, R. K.

    2008-12-01

    With the advent of high temperature reactors, nuclear energy, in addition to producing electricity, has shown enormous potential for the production of alternate transport energy carrier such as hydrogen. High efficiency hydrogen production processes need process heat at temperatures around 1173-1223 K. Bhabha Atomic Research Centre (BARC), is currently developing concepts of high temperature reactors capable of supplying process heat around 1273 K. These reactors would provide energy to facilitate combined production of hydrogen, electricity, and drinking water. Compact high temperature reactor is being developed as a technology demonstrator for associated technologies. Design has been also initiated for a 600 MWth innovative high temperature reactor. High temperature reactor development programme has opened new avenues for research in areas like advanced nuclear fuels, high temperature and corrosion resistant materials and protective coatings, heavy liquid metal coolant technologies, etc. The paper highlights design of these reactors and their material related requirements.

  16. High temperature sensor

    DOEpatents

    Tokarz, Richard D.

    1982-01-01

    A high temperature sensor includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range (1,000 to 2,000 K.). When required, the sensor can be encased within a ceramic protective coating.

  17. High-Temperature Superconductivity

    NASA Astrophysics Data System (ADS)

    Tanaka, Shoji

    2006-12-01

    A general review on high-temperature superconductivity was made. After prehistoric view and the process of discovery were stated, the special features of high-temperature superconductors were explained from the materials side and the physical properties side. The present status on applications of high-temperature superconductors were explained on superconducting tapes, electric power cables, magnets for maglev trains, electric motors, superconducting quantum interference device (SQUID) and single flux quantum (SFQ) devices and circuits.

  18. High temperature refrigerator

    DOEpatents

    Steyert, Jr., William A.

    1978-01-01

    A high temperature magnetic refrigerator which uses a Stirling-like cycle in which rotating magnetic working material is heated in zero field and adiabatically magnetized, cooled in high field, then adiabatically demagnetized. During this cycle said working material is in heat exchange with a pumped fluid which absorbs heat from a low temperature heat source and deposits heat in a high temperature reservoir. The magnetic refrigeration cycle operates at an efficiency 70% of Carnot.

  19. High temperature measuring device

    DOEpatents

    Tokarz, Richard D.

    1983-01-01

    A temperature measuring device for very high design temperatures (to 2,000.degree. C.). The device comprises a homogenous base structure preferably in the form of a sphere or cylinder. The base structure contains a large number of individual walled cells. The base structure has a decreasing coefficient of elasticity within the temperature range being monitored. A predetermined quantity of inert gas is confined within each cell. The cells are dimensionally stable at the normal working temperature of the device. Increases in gaseous pressure within the cells will permanently deform the cell walls at temperatures within the high temperature range to be measured. Such deformation can be correlated to temperature by calibrating similarly constructed devices under known time and temperature conditions.

  20. High-temperature sensor

    DOEpatents

    Not Available

    1981-01-29

    A high temperature sensor is described which includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range (1000 to 2000/sup 0/K). When required, the sensor can be encased within a ceramic protective coating.

  1. River Temperature Dynamics and Habitat Characteristics as Predictors of Salmonid Abundance using Fiber-Optic Distributed Temperature Sensing

    NASA Astrophysics Data System (ADS)

    Gryczkowski, L.; Gallion, D.; Haeseker, S.; Bower, R.; Collier, M.; Selker, J. S.; Scherberg, J.; Henry, R.

    2011-12-01

    Salmonids require cool water for all life stages, including spawning and growth. Excessive water temperature causes reduced growth and increased disease and mortality. During the summer, salmonids seek local zones of cooler water as a refuge from elevated temperatures. They also prefer specific habitat features such as boulders and overhanging vegetation. The purpose of this study is to determine whether temperature dynamics or commonly measured fish habitat metrics best explain salmonid abundance. The study site was a 2-kilometer reach of the Walla Walla River near Milton-Freewater, OR, USA, which provides habitat for the salmonids chinook salmon (Oncorhynchus tshawytscha), steelhead/rainbow trout (Oncorhynchus mykiss), mountain whitefish (Prosopium williamsoni), and the endangered bull trout (Salvelinus confluentus). The Walla Walla River is listed as an impaired water body under section 303(d) of the Clean Water Act due to temperature. The associated total maximum daily load (TMDL) calls for temperatures to be below 18 °C at all times for salmonid rearing and migration; however, river temperatures surpassed 24 °C in parts of the study reach in 2009. The two largest factors contributing to the warmer water are reduced riparian vegetation, which decreases shading and increases direct solar radiation, and decreased summer flows caused by diversions and irrigation for agriculture. Fiber-optic distributed temperature sensing has emerged as a unique and powerful tool for ecological applications because of its high spatial and temporal resolution. In this study, meter-scale temperature measurements were obtained at 15-minute intervals along the length of the study reach, allowing for the detection and quantification of cold water inflows during the summer of 2009. The cold water inflows were classified as groundwater or hyporheic sources based on the diurnal temperature patterns. Snorkel surveys were conducted in mid-July and mid-August, 2009 to enumerate salmonid

  2. Jovian Mid-Infrared Aurora, Hydrocarbon Abundances and Temperature Prior to Juno's Arrival

    NASA Astrophysics Data System (ADS)

    Kostiuk, Theodor; Livengood, Timothy A.; Hewagama, Tilak; Kolasinski, John

    2016-10-01

    We report on ground-based measurements of Jupiter's thermal infrared aurora, ethane abundances and temperature prior to Juno's arrival at Jupiter in July 2016. Measurements covering spectral and altitude regions that will complement Juno observational capabilities were made April 18-22, 2016, with the GSFC Heterodyne Instrument for Planetary Wind And Composition (HIPWAC) on the NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii. The ultra-high spectral resolution infrared heterodyne spectroscopy (IRHS) measures fully resolved individual spectral lines whose shape provides unique information on variability of temperature and abundance. Ethane line spectra near 12-micrometer wavelength will be used to determine the intensities of auroral emission from Jupiter's polar regions and retrieve ethane abundance and temperature changes on and off the north polar "hot spot" region. Results will be compared to a 30-year study of this thermal infrared aurora with ground-based IRHS and with Voyager IRIS and Cassini CIRS measurements. Additional measurements during Juno's orbital mission phase are also planned. Analyses of the variability of the earlier measurements suggest that the thermal IR auroral emission may be low during the Juno –Jupiter encounter. Results will be useful for the Juno mission, since it does not have instrumentation in this spectral region and this work provides complementary information and diagnostic for studying Jupiter in a spectral region and altitude range not directly probed by Juno.

  3. High-Temperature Superconductivity

    SciTech Connect

    Peter Johnson

    2008-11-05

    Like astronomers tweaking images to gain a more detailed glimpse of distant stars, physicists at Brookhaven National Laboratory have found ways to sharpen images of the energy spectra in high-temperature superconductors — materials that carry electrical c

  4. High Temperature Capacitor Development

    SciTech Connect

    John Kosek

    2009-06-30

    The absence of high-temperature electronics is an obstacle to the development of untapped energy resources (deep oil, gas and geothermal). US natural gas consumption is projected to grow from 22 trillion cubic feet per year (tcf) in 1999 to 34 tcf in 2020. Cumulatively this is 607 tcf of consumption by 2020, while recoverable reserves using current technology are 177 tcf. A significant portion of this shortfall may be met by tapping deep gas reservoirs. Tapping these reservoirs represents a significant technical challenge. At these depths, temperatures and pressures are very high and may require penetrating very hard rock. Logistics of supporting 6.1 km (20,000 ft) drill strings and the drilling processes are complex and expensive. At these depths up to 50% of the total drilling cost may be in the last 10% of the well depth. Thus, as wells go deeper it is increasingly important that drillers are able to monitor conditions down-hole such as temperature, pressure, heading, etc. Commercial off-the-shelf electronics are not specified to meet these operating conditions. This is due to problems associated with all aspects of the electronics including the resistors and capacitors. With respect to capacitors, increasing temperature often significantly changes capacitance because of the strong temperature dependence of the dielectric constant. Higher temperatures also affect the equivalent series resistance (ESR). High-temperature capacitors usually have low capacitance values because of these dielectric effects and because packages are kept small to prevent mechanical breakage caused by thermal stresses. Electrolytic capacitors do not operate at temperatures above 150oC due to dielectric breakdown. The development of high-temperature capacitors to be used in a high-pressure high-temperature (HPHT) drilling environment was investigated. These capacitors were based on a previously developed high-voltage hybridized capacitor developed at Giner, Inc. in conjunction with a

  5. High temperature pressure gauge

    DOEpatents

    Echtler, J. Paul; Scandrol, Roy O.

    1981-01-01

    A high temperature pressure gauge comprising a pressure gauge positioned in fluid communication with one end of a conduit which has a diaphragm mounted in its other end. The conduit is filled with a low melting metal alloy above the diaphragm for a portion of its length with a high temperature fluid being positioned in the remaining length of the conduit and in the pressure gauge.

  6. High-temperature electronics

    NASA Technical Reports Server (NTRS)

    Matus, Lawrence G.; Seng, Gary T.

    1990-01-01

    To meet the needs of the aerospace propulsion and space power communities, the high temperature electronics program at the Lewis Research Center is developing silicon carbide (SiC) as a high temperature semiconductor material. This program supports a major element of the Center's mission - to perform basic and developmental research aimed at improving aerospace propulsion systems. Research is focused on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of SiC devices.

  7. High Temperature ESP Monitoring

    SciTech Connect

    Jack Booker; Brindesh Dhruva

    2011-06-20

    The objective of the High Temperature ESP Monitoring project was to develop a downhole monitoring system to be used in wells with bottom hole well temperatures up to 300°C for measuring motor temperature, formation pressure, and formation temperature. These measurements are used to monitor the health of the ESP motor, to track the downhole operating conditions, and to optimize the pump operation. A 220 ºC based High Temperature ESP Monitoring system was commercially released for sale with Schlumberger ESP motors April of 2011 and a 250 ºC system with will be commercially released at the end of Q2 2011. The measurement system is now fully qualified, except for the sensor, at 300 °C.

  8. High temperature probe

    DOEpatents

    Swan, Raymond A.

    1994-01-01

    A high temperature probe for sampling, for example, smokestack fumes, and is able to withstand temperatures of 3000.degree. F. The probe is constructed so as to prevent leakage via the seal by placing the seal inside the water jacket whereby the seal is not exposed to high temperature, which destroys the seal. The sample inlet of the probe is also provided with cooling fins about the area of the seal to provide additional cooling to prevent the seal from being destroyed. Also, a heated jacket is provided for maintaining the temperature of the gas being tested as it passes through the probe. The probe includes pressure sensing means for determining the flow velocity of an efficient being sampled. In addition, thermocouples are located in various places on the probe to monitor the temperature of the gas passing there through.

  9. High temperature structural silicides

    SciTech Connect

    Petrovic, J.J.

    1997-03-01

    Structural silicides have important high temperature applications in oxidizing and aggressive environments. Most prominent are MoSi{sub 2}-based materials, which are borderline ceramic-intermetallic compounds. MoSi{sub 2} single crystals exhibit macroscopic compressive ductility at temperatures below room temperature in some orientations. Polycrystalline MoSi{sub 2} possesses elevated temperature creep behavior which is highly sensitive to grain size. MoSi{sub 2}-Si{sub 3}N{sub 4} composites show an important combination of oxidation resistance, creep resistance, and low temperature fracture toughness. Current potential applications of MoSi{sub 2}-based materials include furnace heating elements, molten metal lances, industrial gas burners, aerospace turbine engine components, diesel engine glow plugs, and materials for glass processing.

  10. High Temperature Piezoelectric Drill

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Scott, James; Boudreau, Kate; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom; Zhang, Shujun

    2009-01-01

    The current NASA Decadal mission planning effort has identified Venus as a significant scientific target for a surface in-situ sampling/analyzing mission. The Venus environment represents several extremes including high temperature (460 deg C), high pressure (9 MPa), and potentially corrosive (condensed sulfuric acid droplets that adhere to surfaces during entry) environments. This technology challenge requires new rock sampling tools for these extreme conditions. Piezoelectric materials can potentially operate over a wide temperature range. Single crystals, like LiNbO3, have a Curie temperature that is higher than 1000 deg C and the piezoelectric ceramics Bismuth Titanate higher than 600 deg C. A study of the feasibility of producing piezoelectric drills that can operate in the temperature range up to 500 deg C was conducted. The study includes the high temperature properties investigations of engineering materials and piezoelectric ceramics with different formulas and doping. The drilling performances of a prototype Ultrasonic/Sonic Drill/Corer (USDC) using high temperate piezoelectric ceramics and single crystal were tested at temperature up to 500 deg C. The detailed results of our study and a discussion of the future work on performance improvements are presented in this paper.

  11. High temperature storage loop :

    SciTech Connect

    Gill, David Dennis; Kolb, William J.

    2013-07-01

    A three year plan for thermal energy storage (TES) research was created at Sandia National Laboratories in the spring of 2012. This plan included a strategic goal of providing test capability for Sandia and for the nation in which to evaluate high temperature storage (>650ÀC) technology. The plan was to scope, design, and build a flow loop that would be compatible with a multitude of high temperature heat transfer/storage fluids. The High Temperature Storage Loop (HTSL) would be reconfigurable so that it was useful for not only storage testing, but also for high temperature receiver testing and high efficiency power cycle testing as well. In that way, HTSL was part of a much larger strategy for Sandia to provide a research and testing platform that would be integral for the evaluation of individual technologies funded under the SunShot program. DOEs SunShot program seeks to reduce the price of solar technologies to 6/kWhr to be cost competitive with carbon-based fuels. The HTSL project sought to provide evaluation capability for these SunShot supported technologies. This report includes the scoping, design, and budgetary costing aspects of this effort

  12. High Temperature Structural Foam

    NASA Technical Reports Server (NTRS)

    Weiser, Erik S.; Baillif, Faye F.; Grimsley, Brian W.; Marchello, Joseph M.

    1997-01-01

    The Aerospace Industry is experiencing growing demand for high performance polymer foam. The X-33 program needs structural foam insulation capable of retaining its strength over a wide range of environmental conditions. The High Speed Research Program has a need for low density core splice and potting materials. This paper reviews the state of the art in foam materials and describes experimental work to fabricate low density, high shear strength foam which can withstand temperatures from -220 C to 220 C. Commercially available polymer foams exhibit a wide range of physical properties. Some with densities as low as 0.066 g/cc are capable of co-curing at temperatures as high as 182 C. Rohacell foams can be resin transfer molded at temperatures up to 180 C. They have moduli of elasticity of 0.19 MPa, tensile strengths of 3.7 Mpa and compressive strengths of 3.6 MPa. The Rohacell foams cannot withstand liquid hydrogen temperatures, however Imi-Tech markets Solimide (trademark) foams which withstand temperatures from -250 C to 200 C, but they do not have the required structural integrity. The research activity at NASA Langley Research Center focuses on using chemical blowing agents to produce polyimide thermoplastic foams capable of meeting the above performance requirements. The combination of blowing agents that decompose at the minimum melt viscosity temperature together with plasticizers to lower the viscosity has been used to produce foams by both extrusion and oven heating. The foams produced exhibit good environmental stability while maintaining structural properties.

  13. High-Temperature Superconductivity

    ScienceCinema

    Peter Johnson

    2016-07-12

    Like astronomers tweaking images to gain a more detailed glimpse of distant stars, physicists at Brookhaven National Laboratory have found ways to sharpen images of the energy spectra in high-temperature superconductors — materials that carry electrical c

  14. HIGH TEMPERATURE THERMOCOUPLE

    DOEpatents

    Eshayu, A.M.

    1963-02-12

    This invention contemplates a high temperature thermocouple for use in an inert or a reducing atmosphere. The thermocouple limbs are made of rhenium and graphite and these limbs are connected at their hot ends in compressed removable contact. The rhenium and graphite are of high purity and are substantially stable and free from diffusion into each other even without shielding. Also, the graphite may be thick enough to support the thermocouple in a gas stream. (AEC)

  15. High temperature thermometric phosphors

    DOEpatents

    Allison, Stephen W.; Cates, Michael R.; Boatner, Lynn A.; Gillies, George T.

    1999-03-23

    A high temperature phosphor consists essentially of a material having the general formula LuPO.sub.4 :Dy.sub.(x),Eu.sub.y) wherein: 0.1 wt %.ltoreq.x.ltoreq.20 wt % and 0.1 wt %.ltoreq.y.ltoreq.20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopent. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions.

  16. High temperature thermometric phosphors

    DOEpatents

    Allison, S.W.; Cates, M.R.; Boatner, L.A.; Gillies, G.T.

    1999-03-23

    A high temperature phosphor consists essentially of a material having the general formula LuPO{sub 4}:Dy{sub x},Eu{sub y} wherein: 0.1 wt % {<=} x {<=} 20 wt % and 0.1 wt % {<=} y {<=} 20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopant. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions. 2 figs.

  17. High temperature adsorption measurements

    SciTech Connect

    Bertani, R.; Parisi, L.; Perini, R.; Tarquini, B.

    1996-12-31

    Adsorption phenomena are a rich and rather new field of study in geothermal research, in particular at very high temperature. ENEL is interested in the exploitation of geothermal regions with super-heated steam, and it is important to understand the behavior of water-rock interaction. We have analyzed in the 170-200{degrees}C temperature range four samples of Monteverdi cuttings; the next experimental effort will be at 220{degrees}C and over in 1996. The first results of the 1995 runs are collected in this paper. We can highlight four main items: (1) At relative pressures over 0.6 the capillarity forces are very important. (2) There is no significant temperature effect. (3) Adsorbed water can be present, and it is able to multiply by a factor of 15 the estimated reserve of super-heated steam only. (4) Pores smaller than 15 {Angstrom} do not contribute to the adsorbed mass.

  18. High temperature adsorption measurements

    SciTech Connect

    Bertani, R.; Parisi, L.; Perini, R.; Tarquini, B.

    1996-01-24

    Adsorption phenomena are a rich and rather new field of study in geothermal research, in particular at very high temperature. ENEL is interested in the exploitation of geothermal regions with superheated steam, and it is important to understand the behavior of water-rock interaction. We have analyzed in the 170-200 °C temperature range four samples of Monteverdi cuttings; the next experimental effort will be at 220 °C and over in 1996. The first results of the 1995 runs are collected in this paper. We can highlight four main items: 1. At relative pressures over 0.6 the capillarity forces are very important. 2. There is no significant temperature effect. 3. Adsorbed water can be present, and it is able to multiply by a factor of 15 the estimated reserve of super-heated steam only. 4. Pores smaller than 15 Å do not contribute to the adsorbed mass.

  19. High Temperature Thermosets

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M.

    1999-01-01

    A thermoset or network polymer is an organic material where the molecules are tied together through chemical bonds (crosslinks) and therefore they cannot move past one another. As a result, these materials exhibit a certain degree of dimensional stability. The chemical composition and the degree of crosslink density of the thermoset have a pronounced effect upon the properties. High temperature thermosets offer a favorable combination of properties that makes them attractive for many applications. Their most important features are the excellent processability particularly of the low molecular weight precusor forms, the chemical and solvent resistance and the dimensional stability. The market for high temperature thermosets will increase as new uses for them are uncovered and new thermosets with better combinations of properties are developed.

  20. High temperature future

    SciTech Connect

    Sheinkopf, K.

    1994-09-01

    During the past few years, there have been dramatic accomplishments and success of high temperature solar thermal systems and significant development of these systems. High temperature technologies, about 500 F and higher, such as dish engines, troughs, central receiver power towers and solar process heat systems, have been tested, demonstrated and used in an array of applications, including many cost-effective utility bulk power production and demand side supply projects in the United States. Large systems provide power and hot water to prisons, schools, nursing homes and other institutions. Joint ventures with industry, utility projects, laboratory design assistance and other activities are building a solid industry of US solar thermal systems ready for use today.

  1. High temperature materials characterization

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.

    1990-01-01

    A lab facility for measuring elastic moduli up to 1700 C was constructed and delivered. It was shown that the ultrasonic method can be used to determine elastic constants of materials from room temperature to their melting points. The ease in coupling high frequency acoustic energy is still a difficult task. Even now, new coupling materials and higher power ultrasonic pulsers are being suggested. The surface was only scratched in terms of showing the full capabilities of either technique used, especially since there is such a large learning curve in developing proper methodologies to take measurements into the high temperature region. The laser acoustic system does not seem to have sufficient precision at this time to replace the normal buffer rod methodology.

  2. A high deuterium abundance at redshift z = 0.7.

    PubMed

    Webb, J K; Carswell, R F; Lanzetta, K M; Ferlet, R; Lemoine, M; Vidal-Madjar, A; Bowen, D V

    1997-07-17

    Of the light elements, the primordial abundance of deuterium relative to hydrogen, (D/H)p, provides the most sensitive diagnostic for the cosmological mass density parameter, omegaB. Recent high-redshift D/H measurements are highly discrepant, although this may reflect observational uncertainties. The larger primordial D/H values imply a low omegaB (requiring the Universe to be dominated by non-baryonic matter), and cause problems for galactic chemical evolution models, which have difficulty in reproducing the steep decline in D/H to the present-day values. Conversely, the lower D/H values measured at high redshift imply an omegaB greater than that derived from 7Li and 4He abundance measurements, and may require a deuterium-abundance evolution that is too low to easily explain. Here we report the first measurement of D/H at intermediate redshift (z = 0.7010), in a gas cloud selected to minimize observational uncertainties. Our analysis yields a value of D/H ((2.0 +/- 0.5) x 10[-4]) which is at the upper end of the range of values measured at high redshifts. This finding, together with other independent observations, suggests that there may be inhomogeneity in (D/H)p of at least a factor of ten.

  3. A high deuterium abundance at redshift z = 0.7.

    PubMed

    Webb, J K; Carswell, R F; Lanzetta, K M; Ferlet, R; Lemoine, M; Vidal-Madjar, A; Bowen, D V

    1997-07-17

    Of the light elements, the primordial abundance of deuterium relative to hydrogen, (D/H)p, provides the most sensitive diagnostic for the cosmological mass density parameter, omegaB. Recent high-redshift D/H measurements are highly discrepant, although this may reflect observational uncertainties. The larger primordial D/H values imply a low omegaB (requiring the Universe to be dominated by non-baryonic matter), and cause problems for galactic chemical evolution models, which have difficulty in reproducing the steep decline in D/H to the present-day values. Conversely, the lower D/H values measured at high redshift imply an omegaB greater than that derived from 7Li and 4He abundance measurements, and may require a deuterium-abundance evolution that is too low to easily explain. Here we report the first measurement of D/H at intermediate redshift (z = 0.7010), in a gas cloud selected to minimize observational uncertainties. Our analysis yields a value of D/H ((2.0 +/- 0.5) x 10[-4]) which is at the upper end of the range of values measured at high redshifts. This finding, together with other independent observations, suggests that there may be inhomogeneity in (D/H)p of at least a factor of ten. PMID:9230433

  4. Better high temperature sealing

    SciTech Connect

    Adams, W.V.

    1987-01-01

    Acceptance of welded metal bellows designs, superior seal face materials and advancement of environmental control systems has extended the limits of mechanical seals to the operating limits of the process systems themselves. The nonpusher type welded metal bellows designs have overcome past seal hang-up problems. Material combinations such as silicon carbide versus silicon carbide and silicon carbide versus tungsten carbide have proven to be capable of handling the harsh abrasives encountered on high temperature sealing applications. Steam purges have done a good job of flushing away the deposits and sludges that form on the atmospheric side of the seal and cause seal hang-up. Today's field experience shows that hot water at temperatures up to 350/sup 0/F in the seal cavity can be handled with nothing more than a bypass flush per API piping plan 11 as long as adequate vapor pressure of the fluid is available. For temperatures above 350/sup 0/F, only moderate cooling is now required on hot water applications, where full cooling and a reduction of the seal cavity temperature to something below 180/sup 0/F were once necessary. Initially, the move towards high temperature seals was made for safety, long seal life and reliability reasons. Users wanted seals on their equipment that would avoid the danger of catastrophic seal failures in the event the environmental control systems failed. More recently, the economic advantages of running seals hot have been recognized. It is estimated that an annual savings of $1,000 per inch of shaft size can be realized for every 100/sup 0/F of cooling requirements that can be removed from the seal cavity. This cost savings is due to the elimination or reduction of energy sources used to cool the mechanical seal.

  5. Elemental abundances in high-excitation planetary nebulae

    NASA Technical Reports Server (NTRS)

    Marionni, P. A.; Harrington, J. P.

    1981-01-01

    The IUE satellite was used to obtain low dispersion spectra of the high excitation planetary nebulae IC 351, IC 2003, NGC 2022, IC 2165, NGC 2440, Hu 1-2, and IC 5217. Numerical modeling was undertaken to determine the chemical composition of these objects with particular emphasis on obtaining elemental carbon and nitrogen abundances. Large variations in the C/N ratio from object to object are suggested.

  6. High temperature strain gages

    NASA Technical Reports Server (NTRS)

    Gregory, Otto J. (Inventor); You, Tao (Inventor)

    2011-01-01

    A ceramic strain gage based on reactively sputtered indium-tin-oxide (ITO) thin films is used to monitor the structural integrity of components employed in aerospace propulsion systems operating at temperatures in excess of 1500.degree. C. A scanning electron microscopy (SEM) of the thick ITO sensors reveals a partially sintered microstructure comprising a contiguous network of submicron ITO particles with well defined necks and isolated nanoporosity. Densification of the ITO particles was retarded during high temperature exposure with nitrogen thus stabilizing the nanoporosity. ITO strain sensors were prepared by reactive sputtering in various nitrogen/oxygen/argon partial pressures to incorporate more nitrogen into the films. Under these conditions, sintering and densification of the ITO particles containing these nitrogen rich grain boundaries was retarded and a contiguous network of nano-sized ITO particles was established.

  7. High Temperature Piezoelectric Drill

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom

    2012-01-01

    Venus is one of the planets in the solar systems that are considered for potential future exploration missions. It has extreme environment where the average temperature is 460 deg C and its ambient pressure is about 90 atm. Since the existing actuation technology cannot maintain functionality under the harsh conditions of Venus, it is a challenge to perform sampling and other tasks that require the use of moving parts. Specifically, the currently available electromagnetic actuators are limited in their ability to produce sufficiently high stroke, torque, or force. In contrast, advances in developing electro-mechanical materials (such as piezoelectric and electrostrictive) have enabled potential actuation capabilities that can be used to support such missions. Taking advantage of these materials, we developed a piezoelectric actuated drill that operates at the temperature range up to 500 deg C and the mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) configuration. The detailed results of our study are presented in this paper

  8. Highly siderophile element abundances in Eoarchean komatiite and basalt protoliths

    NASA Astrophysics Data System (ADS)

    Frank, Elizabeth A.; Maier, Wolfgang D.; Mojzsis, Stephen J.

    2016-03-01

    Plume-derived, Mg-rich, volcanic rocks (komatiites, high-Mg basalts, and their metamorphic equivalents) can record secular changes in the highly siderophile element (HSE) abundances of mantle sources. An apparent secular time-dependent enrichment trend in HSE abundances from Paleoarchean to Paleoproterozoic mantle-derived rocks could represent the protracted homogenization of a Late Veneer chondritic contaminant into the pre-Late Veneer komatiite source. To search for a possible time dependence of a late accretion signature in the Eoarchean mantle, we report new data from rare >3700 Myr-old mafic and ultramafic schists locked in supracrustal belts from the Inukjuak domain (Québec, Canada) and the Akilia association (West Greenland). Our analysis shows that some of these experienced HSE mobility and/or include a cumulate component (Touboul et al. in Chem Geol 383:63-75, 2014), whereas several of the oldest samples show some of the most depleted HSE abundances measured for rocks of this composition. We consider these new data for the oldest documented rocks of komatiite protolith in light of the Late Veneer hypothesis.

  9. Instabilities of High Temperature Superconductors

    PubMed Central

    Matthias, B. T.; Corenzwit, E.; Cooper, A. S.; Longinotti, L. D.

    1971-01-01

    We have observed the transition temperature of both the cubic and tetragonal phases of several high-temperature β-W superconductors. The instability of the cubic lattice appears to be characteristic of high-temperature superconductors. PMID:16591897

  10. High temperature detonator

    DOEpatents

    Johnson, James O.; Dinegar, Robert H.

    1988-01-01

    A detonator assembly is provided which is usable at high temperatures about 300.degree. C. A detonator body is provided with an internal volume defining an anvil surface. A first acceptor explosive is disposed on the anvil surface. A donor assembly having an ignition element, an explosive material, and a flying plate, are placed in the body effective to accelerate the flying plate to impact the first acceptor explosive on the anvil for detonating the first acceptor explosive. A second acceptor explosive is eccentrically located in detonation relationship with the first acceptor explosive to thereafter effect detonation of a main charge.

  11. High temperature geophysical instrumentation

    SciTech Connect

    Hardee, H.C.

    1988-06-01

    The instrumentation development program was to proceed in parallel with scientific research and was driven by the needs of researchers. The development of these instruments has therefore included numerous geophysical field tests, many of which have resulted in the publication of scientific articles. This paper is a brief summary of some of the major geophysical instruments that have been developed and tested under the High Temperature Geophysics Program. These instruments are briefly described and references are given for further detailed information and for scientific papers that have resulted from the use of these instruments. 9 refs., 14 figs.

  12. High temperature drilling fluids

    SciTech Connect

    Stong, R.E.; Walinsky, S.W.

    1986-01-28

    This patent describes an aqueous drilling fluid suitable for high-temperature use. This fluid is composed of a water base. Clay is suspended in the base and from about 0.01-25 pounds per barrel total composition of a hydrolyzed terpolymer of maleic anhydride, styrene and a third monomer selected from acrylamide, methacrylamide, acrylic acid and metacrylic acid. The molar ratio of maleic anhydride to styrene to the third monomer is from about 30:10:60 to 50:40:10, and the alkali metal, ammonium and lower aliphatic amine salts thereof, the weight-average molecular weight of the hydrolyzed terpolymer is from about 500-10,000.

  13. High Temperature Protonic Conductors

    NASA Technical Reports Server (NTRS)

    Dynys, Fred; Berger, Marie-Helen; Sayir, Ali

    2007-01-01

    High Temperature Protonic Conductors (HTPC) with the perovskite structure are envisioned for electrochemical membrane applications such as H2 separation, H2 sensors and fuel cells. Successive membrane commercialization is dependent upon addressing issues with H2 permeation rate and environmental stability with CO2 and H2O. HTPC membranes are conventionally fabricated by solid-state sintering. Grain boundaries and the presence of intergranular second phases reduce the proton mobility by orders of magnitude than the bulk crystalline grain. To enhanced protonic mobility, alternative processing routes were evaluated. A laser melt modulation (LMM) process was utilized to fabricate bulk samples, while pulsed laser deposition (PLD) was utilized to fabricate thin film membranes . Sr3Ca(1+x)Nb(2-x)O9 and SrCe(1-x)Y(x)O3 bulk samples were fabricated by LMM. Thin film BaCe(0.85)Y(0.15)O3 membranes were fabricated by PLD on porous substrates. Electron microscopy with chemical mapping was done to characterize the resultant microstructures. High temperature protonic conduction was measured by impedance spectroscopy in wet air or H2 environments. The results demonstrate the advantage of thin film membranes to thick membranes but also reveal the negative impact of defects or nanoscale domains on protonic conductivity.

  14. High temperature filter materials

    SciTech Connect

    Alvin, M.A.; Lippert, T.E.; Bachovchin, D.M.; Tressler, R.E.

    1992-12-01

    Objectives of this program are to identify the potential long-term thermal/chemical effects that advanced coal-based power generating system environments have on the stability of porous ceramic filter materials, as well as to assess the influence of these effects on filter operating performance and life. We have principally focused our efforts on developing an understanding of the stability of the alumina/mullite filter material at high temperature (i.e., 870, 980, and 1100{degrees}C) under oxidizing conditions which contain gas phase alkali species. Testing has typically been performed in two continuous flow-through, high temperature test facilities at the Westinghouse Science and Technology Center, using 7 cm diameter {times} 6.4 mm thick discs. (Alvin, 1992) Each disc of ceramic filter material is exposed for periods of 100 to 3,000 hours in duration. Additional efforts have been performed at Westinghouse to broaden our understanding of the stability of cordierite, cordierite-silicon nitride, reaction and sintered silicon nitride, and clay bonded silicon carbide under similar simulated advanced coal fired process conditions. The results of these efforts are presented in this paper.

  15. High temperature filter materials

    SciTech Connect

    Alvin, M.A.; Lippert, T.E.; Bachovchin, D.M. . Science and Technology Center); Tressler, R.E. )

    1992-01-01

    Objectives of this program are to identify the potential long-term thermal/chemical effects that advanced coal-based power generating system environments have on the stability of porous ceramic filter materials, as well as to assess the influence of these effects on filter operating performance and life. We have principally focused our efforts on developing an understanding of the stability of the alumina/mullite filter material at high temperature (i.e., 870, 980, and 1100[degrees]C) under oxidizing conditions which contain gas phase alkali species. Testing has typically been performed in two continuous flow-through, high temperature test facilities at the Westinghouse Science and Technology Center, using 7 cm diameter [times] 6.4 mm thick discs. (Alvin, 1992) Each disc of ceramic filter material is exposed for periods of 100 to 3,000 hours in duration. Additional efforts have been performed at Westinghouse to broaden our understanding of the stability of cordierite, cordierite-silicon nitride, reaction and sintered silicon nitride, and clay bonded silicon carbide under similar simulated advanced coal fired process conditions. The results of these efforts are presented in this paper.

  16. High-resolution abundance analysis of HD 140283

    NASA Astrophysics Data System (ADS)

    Siqueira-Mello, C.; Andrievsky, S. M.; Barbuy, B.; Spite, M.; Spite, F.; Korotin, S. A.

    2015-12-01

    Context. HD 140283 is a reference subgiant that is metal poor and confirmed to be a very old star. The element abundances of this type of old star can constrain the nature and nucleosynthesis processes that occurred in its (even older) progenitors. The present study may shed light on nucleosynthesis processes yielding heavy elements early in the Galaxy. Aims: A detailed analysis of a high-quality spectrum is carried out, with the intent of providing a reference on stellar lines and abundances of a very old, metal-poor subgiant. We aim to derive abundances from most available and measurable spectral lines. Methods: The analysis is carried out using high-resolution (R = 81 000) and high signal-to-noise ratio (800 abundances for 26 elements, and NLTE calculations for the species C i, O i, Na i, Mg i, Al i, K i, Ca i, Sr ii, and Ba ii lines. Results: The abundance analysis provided an extensive line list suitable for metal-poor subgiant stars. The results for Li, CNO, α-, and iron peak elements are in good agreement with literature. The newly NLTE Ba abundance, along with a NLTE Eu correction and a 3D Ba correction from literature, leads to [Eu/Ba] = + 0.59 ± 0.18. This result confirms a dominant r-process contribution, possibly together with a very small contribution from the main s-process, to the neutron-capture elements in HD 140283. Overabundances of the lighter heavy elements and the high abundances derived for Ba, La, and Ce favour the operation of the weak r-process in HD 140283

  17. High Temperature Aquifer Storage

    NASA Astrophysics Data System (ADS)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2015-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Apart from the hydrogeological conditions, high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. After one year of planning, construction, and the successful drilling of a research well to 495 m b.s.l. the first large scale heat storage test in the Malm aquifer was finished just before Christmas 2014. An enormous technical challenge was the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10-50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye. Injection and production rates were 15 L/s. About 4 TJ of heat energy were necessary to achieve the desired water temperatures. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for the analysis of the concentration of the tracers and the cation concentrations at sampling intervals of down to 15 minutes. Additional water samples were taken and analyzed for major ions and trace elements in the laboratory. The disassembled heat exchanger proved that precipitation was successfully prevented by adding CO2 to the water before heating

  18. Abundance trend with condensation temperature for stars with different Galactic birth places

    NASA Astrophysics Data System (ADS)

    Adibekyan, V.; Delgado-Mena, E.; Figueira, P.; Sousa, S. G.; Santos, N. C.; González Hernández, J. I.; Minchev, I.; Faria, J. P.; Israelian, G.; Harutyunyan, G.; Suárez-Andrés, L.; Hakobyan, A. A.

    2016-08-01

    Context. During the past decade, several studies reported a correlation between chemical abundances of stars and condensation temperature (also known as Tc trend). However, the real astrophysical nature of this correlation is still debated. Aims: The main goal of this work is to explore the possible dependence of the Tc trend on stellar Galactocentric distances, Rmean. Methods: We used high-quality spectra of about 40 stars observed with the HARPS and UVES spectrographs to derive precise stellar parameters, chemical abundances, and stellar ages. A differential line-by-line analysis was applied to achieve the highest possible precision in the chemical abundances. Results: We confirm previous results that [X/Fe] abundance ratios depend on stellar age and that for a given age, some elements also show a dependence on Rmean. When using the whole sample of stars, we observe a weak hint that the Tc trend depends on Rmean. The observed dependence is very complex and disappears when only stars with similar ages are considered. Conclusions: To conclude on the possible dependence of the Tc trend on the formation place of stars, a larger sample of stars with very similar atmospheric parameters and stellar ages observed at different Galactocentric distances is needed. Based on observations collected with the HARPS spectrograph at the 3.6-m telescope (program ID: 095.D-0717(A)), installed at the La Silla Observatory, ESO (Chile), with the UVES spectrograph at the 8-m Very Large Telescope (program ID: 095.D-0717(B)), installed at the Cerro Paranal Observatory, ESO (Chile). Also based on data obtained from the ESO Science Archive Facility under request numbers: vadibekyan180760, vadibekyan180762, vadibekyan180764, vadibekyan180768, vadibekyan180769, vadibekyan180771, vadibekyan180773, vadibekyan180778, and vadibekyan180779.Tables with stellar parameters and chemical abundances are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or

  19. High Temperature Aquifer Storage

    NASA Astrophysics Data System (ADS)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2016-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. Apart from high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. An enormous technical challenge is the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10 - 50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye, into a depth of about 300 m b.s.l. resp. 470 m b.s.l. Injection and production rates were 15 L/s. To achieve the desired water temperatures, about 4 TJ of heat energy were necessary. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for analysing the concentration of the dyes and the major cations at sampling intervals of down to 15 minutes. Additional water samples were taken and analysed in the laboratory. The disassembled heat exchanger prooved that precipitation was successfully prevented by adding CO2 to the water before heating. Nevertheless, hydrochemical data proved both, dissolution and precipitation processes in the aquifer. This was also suggested by the hydrochemical modelling with PhreeqC and is traced back to mixture dissolution and changing

  20. High temperature interfacial superconductivity

    SciTech Connect

    Bozovic, Ivan; Logvenov, Gennady; Gozar, Adrian Mihai

    2012-06-19

    High-temperature superconductivity confined to nanometer-scale interfaces has been a long standing goal because of potential applications in electronic devices. The spontaneous formation of a superconducting interface in bilayers consisting of an insulator (La.sub.2CuO.sub.4) and a metal (La.sub.1-xSr.sub.xCuO.sub.4), neither of which is superconducting per se, is described. Depending upon the layering sequence of the bilayers, T.sub.c may be either .about.15 K or .about.30 K. This highly robust phenomenon is confined to within 2-3 nm around the interface. After exposing the bilayer to ozone, T.sub.c exceeds 50 K and this enhanced superconductivity is also shown to originate from a 1 to 2 unit cell thick interfacial layer. The results demonstrate that engineering artificial heterostructures provides a novel, unconventional way to fabricate stable, quasi two-dimensional high T.sub.c phases and to significantly enhance superconducting properties in other superconductors. The superconducting interface may be implemented, for example, in SIS tunnel junctions or a SuFET.

  1. Regional-scale directional changes in abundance of tree species along a temperature gradient in Japan.

    PubMed

    Suzuki, Satoshi N; Ishihara, Masae I; Hidaka, Amane

    2015-09-01

    Climate changes are assumed to shift the ranges of tree species and forest biomes. Such range shifts result from changes in abundances of tree species or functional types. Owing to global warming, the abundance of a tree species or functional type is expected to increase near the colder edge of its range and decrease near the warmer edge. This study examined directional changes in abundance and demographic parameters of forest trees along a temperature gradient, as well as a successional gradient, in Japan. Changes in the relative abundance of each of four functional types (evergreen broad-leaved, deciduous broad-leaved, evergreen temperate conifer, and evergreen boreal conifer) and the demography of each species (recruitment rate, mortality, and population growth rate) were analyzed in 39 permanent forest plots across the Japanese archipelago. Directional changes in the relative abundance of functional types were detected along the temperature gradient. Relative abundance of evergreen broad-leaved trees increased near their colder range boundaries, especially in secondary forests, coinciding with the decrease in deciduous broad-leaved trees. Similarly, relative abundance of deciduous broad-leaved trees increased near their colder range boundaries, coinciding with the decrease in boreal conifers. These functional-type-level changes were mainly due to higher recruitment rates and partly to the lower mortality of individual species at colder sites. This is the first report to show that tree species abundances in temperate forests are changing directionally along a temperature gradient, which might be due to current or past climate changes as well as recovery from past disturbances.

  2. Regional-scale directional changes in abundance of tree species along a temperature gradient in Japan.

    PubMed

    Suzuki, Satoshi N; Ishihara, Masae I; Hidaka, Amane

    2015-09-01

    Climate changes are assumed to shift the ranges of tree species and forest biomes. Such range shifts result from changes in abundances of tree species or functional types. Owing to global warming, the abundance of a tree species or functional type is expected to increase near the colder edge of its range and decrease near the warmer edge. This study examined directional changes in abundance and demographic parameters of forest trees along a temperature gradient, as well as a successional gradient, in Japan. Changes in the relative abundance of each of four functional types (evergreen broad-leaved, deciduous broad-leaved, evergreen temperate conifer, and evergreen boreal conifer) and the demography of each species (recruitment rate, mortality, and population growth rate) were analyzed in 39 permanent forest plots across the Japanese archipelago. Directional changes in the relative abundance of functional types were detected along the temperature gradient. Relative abundance of evergreen broad-leaved trees increased near their colder range boundaries, especially in secondary forests, coinciding with the decrease in deciduous broad-leaved trees. Similarly, relative abundance of deciduous broad-leaved trees increased near their colder range boundaries, coinciding with the decrease in boreal conifers. These functional-type-level changes were mainly due to higher recruitment rates and partly to the lower mortality of individual species at colder sites. This is the first report to show that tree species abundances in temperate forests are changing directionally along a temperature gradient, which might be due to current or past climate changes as well as recovery from past disturbances. PMID:25712048

  3. A high deuterium abundance in the early Universe.

    PubMed

    Songaila, A; Wampler, E J; Cowie, L L

    1997-01-01

    Intergalactic gas clouds at high redshifts have element abundances that are close to primordial. The ratio of deuterium to hydrogen (D/H) within such clouds-which is determined from absorption lines in the spectra of more distant quasars that lie along the same line of sight-provides the best estimate of the density of baryons (omegaB) in the Universe. Previous estimates of D/H in the early Universe have yielded values that differ by about an order of magnitude, with the lower values implying a high density of baryons that may be difficult to reconcile with both estimates of the primordial abundances of other light elements (especially 4He) and the known number of light neutrinos. The accuracy of such D/H determinations is heavily dependent on the inferred column density of neutral hydrogen in the absorbing clouds. Here we report an independent measurement of the neutral hydrogen column density in the cloud towards the quasar Q1937 - 1009, for which one of the low D/H values was derived. Our measurement requires a substantial revision to the D/H value reported previously; we obtain a lower limit of D/H > 4 x 10(-5) for this cloud, which implies omegaB < 0.016 for a Hubble constant of 100 km s(-1) Mpc(-1). This reduced upper limit for the baryon density relieves any conflict with standard Big Bang nucleosynthesis.

  4. Nonlinear response of trout abundance to summer stream temperatures across a thermally diverse montane landscape

    USGS Publications Warehouse

    Isaak, D.J.; Hubert, W.A.

    2004-01-01

    Stream temperature is a fundamental physical factor that affects the distribution and abundance of salmonids, but empirical inconsistencies exist regarding the nature of this relationship in wild populations. We sampled trout populations composed primarily of cutthroat trout Oncorhynchus clarki but also including brown trout Salmo trutta and brook trout Salvelinus fontinalis at 102 reaches on 24 first- to fourth-order streams across a thermally diverse montane landscape. Curves fit to scatterplots of density and biomass versus mean July-August stream temperatures suggested nonlinear, dome-shaped responses. Peaks occurred near mean stream temperatures of 12??C; x-intercepts were near 3??C and 21??C. We conclude that inconsistencies in previously reported temperature-abundance relationships for wild trout populations may have resulted from sampling only a subset of the thermal environments occupied by a species. Researchers analyzing this relationship should be cognizant of the range of temperatures studied and the expected form of the relationship over that range.

  5. High Temperature Superconducting Materials Database

    National Institute of Standards and Technology Data Gateway

    SRD 149 NIST High Temperature Superconducting Materials Database (Web, free access)   The NIST High Temperature Superconducting Materials Database (WebHTS) provides evaluated thermal, mechanical, and superconducting property data for oxides and other nonconventional superconductors.

  6. High Temperature Thermoelectric Materials

    NASA Astrophysics Data System (ADS)

    Ioannidou, A. A.; Rull, M.; Martin-Gonzalez, M.; Moure, A.; Jacquot, A.; Niarchos, D.

    2014-07-01

    The use of microwave energy for materials processing has a major potential and real advantages over conventional heating such as (1) time and energy savings, (2) rapid heating rates (volumetric heating vs. conduction), (3) considerably reduced processing time and temperature, (4) fine microstructures and hence improved mechanical properties and better product performance, and (5) finally lower environmental impact. In this study, we investigated the use of microwave-assisted synthesis to synthesize a series of Co1- x Fe x Sb3 using this novel approach, which gave high quality materials with little or no impurities in a fraction of the time needed for conventional synthesis. X-ray diffraction analysis was used to examine the structure and the lattice parameters of the samples, while scanning electron microscopy with energy dispersive x-ray spectroscopy was used to study the morphology of the compounds. The samples were sintered by spark plasma sintering, and the highest ZT of 0.33 was obtained for x = 0.2 at 700 K.

  7. Early-type galaxy archeology: Ages, abundance ratios, and effective temperatures from full-spectrum fitting

    SciTech Connect

    Conroy, Charlie; Graves, Genevieve J.; Van Dokkum, Pieter G.

    2014-01-01

    The stellar populations of galaxies hold vital clues to their formation histories. In this paper we present results based on modeling stacked spectra of early-type galaxies drawn from the Sloan Digital Sky Survey as a function of velocity dispersion, σ, from 90 km s{sup –1} to 300 km s{sup –1}. The spectra are of extremely high quality, with typical signal-to-noise ratio of 1000 Å{sup –1}, and a wavelength coverage of 4000 Å –8800 Å. Our population synthesis model includes variation in 16 elements from C to Ba, a two-component star formation history, the shift in effective temperature, Δ T {sub eff}, of the stars with respect to a solar metallicity isochrone, and the stellar initial mass function, among other parameters. In our approach we fit the full optical spectra rather than a select number of spectral indices and are able to, for the first time, measure the abundances of the elements V, Cr, Mn, Co, and Ni from the integrated light of distant galaxies. Our main results are as follows: (1) light-weighted stellar ages range from 6-12 Gyr from low to high σ; (2) [Fe/H] varies by less than 0.1 dex across the entire sample; (3) Mg closely tracks O, and both increase from ≈0.0 at low σ to ∼0.25 at high σ; Si and Ti show a shallower rise with σ, and Ca tracks Fe rather than O; (4) the iron peak elements V, Cr, Mn, and Ni track Fe, while Co tracks O, suggesting that Co forms primarily in massive stars; (5) C and N track O over the full sample and [C/Fe] and [N/Fe] exceed 0.2 at high σ; and (6) the variation in Δ T {sub eff} with total metallicity closely follows theoretical predictions based on stellar evolution theory. This last result is significant because it implies that we are robustly solving not only for the detailed abundance patterns but also the detailed temperature distributions (i.e., isochrones) of the stars in these galaxies. A variety of tests reveal that the systematic uncertainties in our measurements are probably 0.05 dex or

  8. A data-driven approach for retrieving temperatures and abundances in brown dwarf atmospheres

    SciTech Connect

    Line, Michael R.; Fortney, Jonathan J.; Marley, Mark S.; Sorahana, Satoko

    2014-09-20

    Brown dwarf spectra contain a wealth of information about their molecular abundances, temperature structure, and gravity. We present a new data driven retrieval approach, previously used in planetary atmosphere studies, to extract the molecular abundances and temperature structure from brown dwarf spectra. The approach makes few a priori physical assumptions about the state of the atmosphere. The feasibility of the approach is first demonstrated on a synthetic brown dwarf spectrum. Given typical spectral resolutions, wavelength coverage, and noise, property precisions of tens of percent can be obtained for the molecular abundances and tens to hundreds of K on the temperature profile. The technique is then applied to the well-studied brown dwarf, Gl 570D. From this spectral retrieval, the spectroscopic radius is constrained to be 0.75-0.83 R {sub J}, log (g) to be 5.13-5.46, and T {sub eff} to be between 804 and 849 K. Estimates for the range of abundances and allowed temperature profiles are also derived. The results from our retrieval approach are in agreement with the self-consistent grid modeling results of Saumon et al. This new approach will allow us to address issues of compositional differences between brown dwarfs and possibly their formation environments, disequilibrium chemistry, and missing physics in current grid modeling approaches as well as a many other issues.

  9. Cosmological and astrophysical consequences of a high primordial deuterium abundance

    NASA Astrophysics Data System (ADS)

    Vangioni-Flam, Elisabeth; Casse, Michel

    1995-03-01

    We explore the consequences of the first detection of deuterium in a high-redshift, very metal-poor absorbing cloud complex, D/H = (1.9-2.5) x 10-4, by Songaila et al. and Carswell et al., obtained with the Keck telescope. This value reflects closely the primordial abundance ratio provided that the observed spectral features are not due to the corruption of the signal by an errant hydrogen cloud of misfortunate velocity. Assuming that the measured D abundance is free from contamination, the baryon/photon ratio is now confined to the range 1.3-2 (instead of 3-4 and more), in both the classical and inhomogeneous big bangs. Other light elements (He-3, He-4 and Li-7) are consistent with these figures. The low baryonic density of the universe that ensues leaves no room for baryonic matter in the extended halos of elliptical galaxies, especially if the Hubble parameter is close to 100 km/s/Mpc. Nonbaryonic matter clearly dominates the gravitating mass of clusters of galaxies. The upper limit of the gas density at high redshift (before bulk galaxy formation) is now consistent with the baryonic one. A massive destruction of deuterium, in the course of the evolution of the galaxy (say, by a factor of 10-25) is required to match the D/H ratio observed in the local interstellar medium. The higher D destruction proposed up to now corresponds to galactic evolutionary models devised by Vangioni-Flam & Audouze (1988) and Vangioni-Flam, Olive, & Prantzos (1994). We discuss the virtues and the limits of this class of models and propose an alternative based on mass related to a galactic wind.

  10. Metallic abundances of the 2002 Leonid meteor deduced from high-definition TV spectra

    NASA Astrophysics Data System (ADS)

    Kasuga, T.; Yamamoto, T.; Watanabe, J.; Ebizuka, N.; Kawakita, H.; Yano, H.

    2005-05-01

    High-definition TV spectra in the ultraviolet-visible region were obtained during the 2002 Leonid aircraft campaign. We analyze the spectra of the brightest fireball that appeared at 03h 47m 54s UT on Nov. 19, 2002 and identify the neutral atoms, mainly MgI, FeI, CaI, and NaI in the observed wavelengths between 300-650 nm. The singly ionized atomic emissions, CaII and MgII lines, also appeared in the spectrum in several epochs during the series of video frames. From analysis of the spectra, time variation in the abundances of metallic atoms, along with their electronic excitation and blackbody temperatures, were obtained assuming the Local Thermal Equilibrium (LTE) condition. Both Fe and Ca abundances relative to Mg are lower than the solar abundance, while Na is slightly higher. We found correlation between the excitation temperature and the abundance of Ca, which suggests incomplete evaporation of the Ca due to intrinsic refractoriness. A search for bands of CHON-related molecules, such as OH and CN, is not successful in the brightest fireball in this study.

  11. High-temperature piezoelectric sensing.

    PubMed

    Jiang, Xiaoning; Kim, Kyungrim; Zhang, Shujun; Johnson, Joseph; Salazar, Giovanni

    2013-01-01

    Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented. PMID:24361928

  12. High-Temperature Piezoelectric Sensing

    PubMed Central

    Jiang, Xiaoning; Kim, Kyungrim; Zhang, Shujun; Johnson, Joseph; Salazar, Giovanni

    2014-01-01

    Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented. PMID:24361928

  13. The effects of mass flow on the temperature and abundance structure of the solar transition region

    NASA Technical Reports Server (NTRS)

    Woods, D. T.; Holzer, Thomas E.

    1991-01-01

    The density and temperature structure of a multicomponent plasma consisting of electrons, protons, ionized helium, and a trace minor ion species are computed. The equations of force and energy balance for this model are developed and solved. It is found that in the case of downflows the minor ion temperature can be significantly hotter than the electron temperature, and significant abundance enhancements are possible due to the slowdown of the minor species from the effect of the thermal force. A simple physical picture of the source of the thermal force is given.

  14. Phylogeographical disjunction in abundant high-dispersal littoral gastropods.

    PubMed

    Waters, J M; King, T M; O'Loughlin, P M; Spencer, H G

    2005-08-01

    Abstract Phylogeographical disjunctions in high-dispersal marine taxa are variously ascribed to palaeogeographical conditions or contemporary ecological factors. Associated biogeographical studies, however, seldom incorporate the sampling design required to confidently discriminate among such competing hypotheses. In the current study, over 7800 gastropod specimens were examined for operculum colour, and 129 specimens genetically, to test ecological and historical biogeographical hypotheses relating to biogeographical disjunction in the Southern Hemisphere, and to southern Australia in particular. Mitochondrial DNA sequence analysis of the high-dispersal intertidal gastropod Nerita atramentosa in southern Australia (88 specimens; 18 localities) revealed an east-west phylogeographical split involving two highly divergent clades (26.0 +/- 1.9%) exhibiting minimal geographical overlap in the southeast. The eastern clade of Nerita atramentosa is also widespread in northern New Zealand (43 specimens, 10 localities), but no significant genetic differentiation is explained by the Tasman Sea, a 2000-km-wide oceanic barrier. Spatial genetic structure was not detected within either clade, consistent with the species' dispersive planktotrophic phase lasting for 5-6 months. Digital analysis of operculum colouration revealed substantial differences between eastern (tan) and western (black) specimens. Genetic analysis and visual inspection of 88 Australian specimens revealed a completely nonrandom association between mtDNA data and operculum colouration. Independent examination of a further 7822 specimens from 14 sites in southern Australia revealed both colour morphs at all localities, but reinforced the phylogeographical data by indicating a marked turnover in colour morph abundance associated with a palaeogeographical barrier: Wilsons Promontory. This sharp biogeographical disjunction is in marked contrast to the species' high dispersal abilities. The genetic similarity of

  15. Phylogeographical disjunction in abundant high-dispersal littoral gastropods.

    PubMed

    Waters, J M; King, T M; O'Loughlin, P M; Spencer, H G

    2005-08-01

    Abstract Phylogeographical disjunctions in high-dispersal marine taxa are variously ascribed to palaeogeographical conditions or contemporary ecological factors. Associated biogeographical studies, however, seldom incorporate the sampling design required to confidently discriminate among such competing hypotheses. In the current study, over 7800 gastropod specimens were examined for operculum colour, and 129 specimens genetically, to test ecological and historical biogeographical hypotheses relating to biogeographical disjunction in the Southern Hemisphere, and to southern Australia in particular. Mitochondrial DNA sequence analysis of the high-dispersal intertidal gastropod Nerita atramentosa in southern Australia (88 specimens; 18 localities) revealed an east-west phylogeographical split involving two highly divergent clades (26.0 +/- 1.9%) exhibiting minimal geographical overlap in the southeast. The eastern clade of Nerita atramentosa is also widespread in northern New Zealand (43 specimens, 10 localities), but no significant genetic differentiation is explained by the Tasman Sea, a 2000-km-wide oceanic barrier. Spatial genetic structure was not detected within either clade, consistent with the species' dispersive planktotrophic phase lasting for 5-6 months. Digital analysis of operculum colouration revealed substantial differences between eastern (tan) and western (black) specimens. Genetic analysis and visual inspection of 88 Australian specimens revealed a completely nonrandom association between mtDNA data and operculum colouration. Independent examination of a further 7822 specimens from 14 sites in southern Australia revealed both colour morphs at all localities, but reinforced the phylogeographical data by indicating a marked turnover in colour morph abundance associated with a palaeogeographical barrier: Wilsons Promontory. This sharp biogeographical disjunction is in marked contrast to the species' high dispersal abilities. The genetic similarity of

  16. High-resolution NMR of hydrogen in organic solids by DNP enhanced natural abundance deuterium spectroscopy.

    PubMed

    Rossini, Aaron J; Schlagnitweit, Judith; Lesage, Anne; Emsley, Lyndon

    2015-10-01

    We demonstrate that high field (9.4 T) dynamic nuclear polarization (DNP) at cryogenic (∼100 K) sample temperatures enables the rapid acquisition of natural abundance (1)H-(2)H cross-polarization magic angle spinning (CPMAS) solid-state NMR spectra of organic solids. Spectra were obtained by impregnating substrates with a solution of the stable DNP polarizing agent TEKPol in tetrachloroethane. Tetrachloroethane is a non-solvent for the solids, and the unmodified substrates are then polarized through spin diffusion. High quality natural abundance (2)H CPMAS spectra of histidine hydrochloride monohydrate, glycylglycine and theophylline were acquired in less than 2h, providing direct access to hydrogen chemical shifts and quadrupolar couplings. The spectral resolution of the (2)H solid-state NMR spectra is comparable to that of (1)H spectra obtained with state of the art homonuclear decoupling techniques.

  17. High-resolution NMR of hydrogen in organic solids by DNP enhanced natural abundance deuterium spectroscopy

    NASA Astrophysics Data System (ADS)

    Rossini, Aaron J.; Schlagnitweit, Judith; Lesage, Anne; Emsley, Lyndon

    2015-10-01

    We demonstrate that high field (9.4 T) dynamic nuclear polarization (DNP) at cryogenic (∼100 K) sample temperatures enables the rapid acquisition of natural abundance 1H-2H cross-polarization magic angle spinning (CPMAS) solid-state NMR spectra of organic solids. Spectra were obtained by impregnating substrates with a solution of the stable DNP polarizing agent TEKPol in tetrachloroethane. Tetrachloroethane is a non-solvent for the solids, and the unmodified substrates are then polarized through spin diffusion. High quality natural abundance 2H CPMAS spectra of histidine hydrochloride monohydrate, glycylglycine and theophylline were acquired in less than 2 h, providing direct access to hydrogen chemical shifts and quadrupolar couplings. The spectral resolution of the 2H solid-state NMR spectra is comparable to that of 1H spectra obtained with state of the art homonuclear decoupling techniques.

  18. Short-term effects of temperature on the abundance and diversity of magnetotactic cocci

    PubMed Central

    Lin, Wei; Wang, Yinzhao; Pan, Yongxin

    2012-01-01

    Temperature is one of the most important climate factors that can regulate the activity and growth of organisms. However, it is so far unclear how temperature influences the abundance and community composition of magnetotactic bacteria (MTB) that mineralize intracellular magnetite and/or greigite magnetosomes and play significant roles in the global iron cycling and sediment magnetization. To address this specific problem, in this study we have assessed the impact of temperature on freshwater magnetotactic cocci through laboratory microcosm simulations. Microcosms containing MTB were exposed to four constant temperatures ranging from 9°C to 37°C. After 10 days and 28 days of incubation, no significant differences in abundance were detected in microcosms at 9°C, 15°C, and 26°C (Student's t-test, P > 0.05); however, microcosms exposed to 37°C exhibited a significant decrease of magnetotactic cocci abundance (P < 0.05). Dendrogram analysis of community-amplified ribosomal DNA restriction analysis (community ARDRA) banding patterns distinguished the 37°C samples from samples at lower temperatures regardless of incubation periods. Furthermore, clone library analysis revealed that most of the operational taxonomic units (OTUs) detected in samples from 9°C to 26°C were absent from the 37°C microcosms, whereas six OTUs were exclusively detected in the 37°C samples. Community compositions from four incubation temperatures were further compared using statistical phylogenetic methods (UniFrac and LIBSHUFF), which revealed that the 37°C samples harbored phylogenetically distinct MTB communities compared to those found in 9°C, 15°C, and 26°C samples. Taken together, our results indicate that elevated temperature can influence the abundance and diversity of dominant members of magnetotactic cocci. This linkage further infers that the abundance and diversity of MTB (e.g., based on the fossil magnetosomes) may be useful in reconstruction of paleotemperature. PMID

  19. High-temperature-measuring device

    DOEpatents

    Not Available

    1981-01-27

    A temperature measuring device for very high design temperatures (to 2000/sup 0/C) is described. The device comprises a homogenous base structure preferably in the form of a sphere or cylinder. The base structure contains a large number of individual walled cells. The base structure has a decreasing coefficient of elasticity within the temperature range being monitored. A predetermined quantity of inert gas is confined within each cell. The cells are dimensonally stable at the normal working temperature of the device. Increases in gaseous pressure within the cells will permanently deform the cell walls at temperatures within the high temperature range to be measured. Such deformation can be correlated to temperature by calibrating similarly constructed devices under known time and temperature conditions.

  20. CHANDRA-LETGS X-ray observations of Capella. Temperature, density and abundance diagnostics

    NASA Astrophysics Data System (ADS)

    Mewe, R.; Raassen, A. J. J.; Drake, J. J.; Kaastra, J. S.; van der Meer, R. L. J.; Porquet, D.

    2001-03-01

    We report an analysis of the X-ray spectrum of Capella from 6 to 175 Å obtained with the Low Energy Transmission Grating Spectrometer (LETGS) on board of the X-ray space observatory CHANDRA. Many emission line features appear that can be resolved much better as compared to former instruments (EUVE and ASCA). Coronal electron densities (ne) and temperatures (T) of brightly emitting regions are constrained by an analysis of ratios of density- and temperature-sensitive lines of helium-like ions and highly ionized iron atoms. Lines emitted by e.g., O VII & VIII, Mg X-XII, Si XII-XIV, Fe IX, X & XV-XXIII are used to derive T. Line ratios in the helium-like triplets of C V, N VI, O VII, Mg XI, and Si XIII yield T in the range 0.5-10 MK, and ne in the range 109-1013 cm-3. The Fe IX/X ratio yields T =~ 0.9 MK, while lines from Fe XVIII to XXII give T ~ 6-10 MK. Flux ratios of Fe XX-XXII lines indicate for the electron densities an upper limit in the range ne <~ (2-5) 1012 cm-3. From line ratios of Fe XVII and Fe XVIII we derive constraints on the optical depth tau of ~ 1-1.5. An emission measure distribution is derived from Fe line intensities. Results for element abundances (relative to Fe) from a 4-T model are: O and Ne/Fe about solar, N, Mg and Si/Fe ~ 2x solar. The results for T and ne are described in terms of quasi-static coronal loop models and it is shown that the X-ray emission originates from compact structures much smaller than the stellar radii.

  1. Temperature-dependent nuclear partition functions and abundances in the stellar interior

    NASA Astrophysics Data System (ADS)

    Nabi, Jameel-Un; Nasser Tawfik, Abdel; Ezzelarab, Nada; Abas Khan, Ali

    2016-05-01

    We calculate the temperature-dependent nuclear partition functions (TDNPFs) and nuclear abundances for 728 nuclei, assuming nuclear statistical equilibrium (NSE). The theories of stellar evolution support NSE. Discrete nuclear energy levels have been calculated microscopically, using the pn-QRPA theory, up to an excitation energy of 10 MeV in the calculation of the TDNPFs. This feature of our paper distinguishes it from previous calculations. Experimental data is also incorporated wherever available to ensure the reliability of our results. Beyond 10 MeV, we employ a simple Fermi gas model and perform integration over the nuclear level densities to approximate the TDNPFs. We calculate nuclidic abundances, using the Saha equation, as a function of three parameters: stellar density, stellar temperature and the lepton-to-baryon content of stellar matter. All these physical parameters are considered to be extremely important in the stellar interior. The results obtained in this paper show that the equilibrium configuration of nuclei remains unaltered by increasing the stellar density (only the calculated nuclear abundances increase by roughly the same order of magnitude). Increasing the stellar temperature smoothes the equilibrium configuration showing peaks at the neutron-number magic nuclei.

  2. Water abundances in high-mass protostellar envelopes: Herschel observations with HIFI

    NASA Astrophysics Data System (ADS)

    Marseille, M. G.; van der Tak, F. F. S.; Herpin, F.; Wyrowski, F.; Chavarría, L.; Pietropaoli, B.; Baudry, A.; Bontemps, S.; Cernicharo, J.; Jacq, T.; Frieswijk, W.; Shipman, R.; van Dishoeck, E. F.; Bachiller, R.; Benedettini, M.; Benz, A. O.; Bergin, E.; Bjerkeli, P.; Blake, G. A.; Braine, J.; Bruderer, S.; Caselli, P.; Caux, E.; Codella, C.; Daniel, F.; Dieleman, P.; di Giorgio, A. M.; Dominik, C.; Doty, S. D.; Encrenaz, P.; Fich, M.; Fuente, A.; Gaier, T.; Giannini, T.; Goicoechea, J. R.; de Graauw, Th.; Helmich, F.; Herczeg, G. J.; Hogerheijde, M. R.; Jackson, B.; Javadi, H.; Jellema, W.; Johnstone, D.; Jørgensen, J. K.; Kester, D.; Kristensen, L. E.; Larsson, B.; Laauwen, W.; Lis, D.; Liseau, R.; Luinge, W.; McCoey, C.; Megej, A.; Melnick, G.; Neufeld, D.; Nisini, B.; Olberg, M.; Parise, B.; Pearson, J. C.; Plume, R.; Risacher, C.; Roelfsema, P.; Santiago-García, J.; Saraceno, P.; Siegel, P.; Stutzki, J.; Tafalla, M.; van Kempen, T. A.; Visser, R.; Wampfler, S. F.; Yıldız, U. A.

    2010-10-01

    Aims: We derive the dense core structure and the water abundance in four massive star-forming regions in the hope of understanding the earliest stages of massive star formation. Methods: We present Herschel/HIFI observations of the para-H2O 111-000 and 202-111 and the para-H_218O 111-000 transitions. The envelope contribution to the line profiles is separated from contributions by outflows and foreground clouds. The envelope contribution is modeled with Monte-Carlo radiative transfer codes for dust and molecular lines (MC3D and RATRAN), and the water abundance and the turbulent velocity width as free parameters. Results: While the outflows are mostly seen in emission in high-J lines, envelopes are seen in absorption in ground-state lines, which are almost saturated. The derived water abundances range from 5×10-10 to 4×10-8 in the outer envelopes. We detect cold clouds surrounding the protostar envelope, thanks to the very high quality of the Herschel/HIFI data and the unique ability of water to probe them. Several foreground clouds are also detected along the line of sight. Conclusions: The low H2O abundances in massive dense cores are in accordance with the expectation that high densities and low temperatures lead to freeze-out of water on dust grains. The spread in abundance values is not clearly linked to physical properties of the sources. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation of NASA.Appendix (pages 6 to 7) is only available in electronic form at http://www.aanda.org

  3. Influences of temperature and nutrients on Synechococcus abundance and biomass in the southern Mid-Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Moisan, Tiffany A.; Blattner, Kristen L.; Makinen, Carla P.

    2010-07-01

    Synechococci are small (<1 μm) coccoid prokaryotes that play a significant ecological role in microbial food webs and are important contributors to carbon and nitrogen biogeochemical cycles. Under funding from NOAA and NASA, we developed a time series observatory to understand the seasonal variability of Synechococcus and other phytoplankton. Our goal is to understand the distribution and relative contribution of Synechococcus to the carbon cycle and how they relate to nutrients and temperature. Synechococcus in the southern Mid-Atlantic Bight exhibited a clear seasonal abundance pattern in both inshore and offshore waters—peaking in abundance (11×10 4 cells ml -1) during warm periods of summer. Synechococci were numerically important during periods of stratification when waters were warm and macronutrients were low. Using a simple algorithm to convert cellular volume to cellular carbon using image analysis, we estimated that Synechococcus cellular carbon ranged from 0.1 to 1.5 pg C per cell and was most significant compared to total particulate carbon in the summer peaking at ˜25% of the total carbon available. No direct correlations were found between Synechococcus abundance and nitrate, nitrite, ammonium, phosphate, and silicate. However, inshore Synechococcus abundance peaked at 10 4 cells ml -1 when nitrogen concentrations were lowest. Our results suggest that Synechococcus is adapted to warm temperatures and are capable of demonstrating rapid growth during summer when macronutrients are limiting. The ability of Synechococcus to take advantage of high summer temperatures, low nutrient concentrations and low light levels allows them to maintain a picoplankton community during periods of low detritus and nanophytoplankton is nutrient limited. Temperature-dependence is important in altering the size spectrum of the phytoplankton community and affects the carbon cycle on the Mid Atlantic Bight.

  4. High temperature interface superconductivity

    DOE PAGES

    Gozar, A.; Bozovic, I.

    2016-01-20

    High-Tc superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-Tc Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both ‘passive’ hetero-structures as well as surface-induced effects by external gating are discussed. Here, wemore » conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.« less

  5. High temperature interface superconductivity

    NASA Astrophysics Data System (ADS)

    Gozar, A.; Bozovic, I.

    2016-02-01

    High-Tc superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-Tc Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both 'passive' hetero-structures as well as surface-induced effects by external gating are discussed. We conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.

  6. High-temperature ceramic receivers

    SciTech Connect

    Jarvinen, P. O.

    1980-01-01

    An advanced ceramic dome cavity receiver is discussed which heats pressurized gas to temperatures above 1800/sup 0/F (1000/sup 0/C) for use in solar Brayton power systems of the dispersed receiver/dish or central receiver type. Optical, heat transfer, structural, and ceramic material design aspects of the receiver are reported and the development and experimental demonstration of a high-temperature seal between the pressurized gas and the high-temperature silicon carbide dome material is described.

  7. Constraining the pickup ion abundance and temperature through the multifluid reconstruction of the Voyager 2 termination shock crossing

    NASA Astrophysics Data System (ADS)

    Zieger, Bertalan; Opher, Merav; Tóth, Gábor; Decker, Robert B.; Richardson, John D.

    2015-09-01

    Voyager 2 observations revealed that the hot solar wind ions (the so-called pickup ions) play a dominant role in the thermodynamics of the termination shock and the heliosheath. The number density and temperature of this hot population, however, have remained unknown, since the plasma instrument on board Voyager 2 can only detect the colder thermal ion component. Here we show that due to the multifluid nature of the plasma, the fast magnetosonic mode splits into a low-frequency fast mode and a high-frequency fast mode. The coupling between the two fast modes results in a quasi-stationary nonlinear wave mode, the "oscilliton," which creates a large-amplitude trailing wave train downstream of the thermal ion shock. By fitting multifluid shock wave solutions to the shock structure observed by Voyager 2, we are able to constrain both the abundance and the temperature of the undetected pickup ions. In our three-fluid model, we take into account the nonnegligible partial pressure of suprathermal energetic electrons (0.022-1.5 MeV) observed by the Low-Energy Charged Particle Experiment instrument on board Voyager 2. The best fitting simulation suggests a pickup ion abundance of 20 ± 3%, an upstream pickup ion temperature of 13.4 ± 2 MK, and a hot electron population with an apparent temperature of ~0.83 MK. We conclude that the actual shock transition is a subcritical dispersive shock wave with low Mach number and high plasma β.

  8. Controls of picophytoplankton abundance and composition in a highly dynamic marine system, the Northern Alboran Sea (Western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Amorim, Ana L.; León, Pablo; Mercado, Jesús M.; Cortés, Dolores; Gómez, Francisco; Putzeys, Sebastien; Salles, Soluna; Yebra, Lidia

    2016-06-01

    The Alboran Sea is a highly dynamic basin which exhibits a high spatio-temporal variability of hydrographic structures (e.g. fronts, gyres, coastal upwellings). This work compares the abundance and composition of picophytoplankton observed across the northern Alboran Sea among eleven cruises between 2008 and 2012 using flow cytometry. We evaluate the seasonal and longitudinal variability of picophytoplankton on the basis of the circulation regimes at a regional scale and explore the presence of cyanobacteria ecotypes in the basin. The maximal abundances obtained for Prochlorococcus, Synechococcus and picoeukaryotes (12.7 × 104, 13.9 × 104 and 8.6 × 104 cells mL- 1 respectively) were consistent with those reported for other adjacent marine areas. Seasonal changes in the abundance of the three picophytoplankton groups were highly significant although they did not match the patterns described for other coastal waters. Higher abundances of Prochlorococcus were obtained in autumn-winter while Synechococcus and picoeukaryotes exhibited a different seasonal abundance pattern depending on the sector (e.g. Synechococcus showed higher abundance in summer in the west sector and during winter in the eastern study area). Additionally, conspicuous longitudinal gradients were observed for Prochlorococcus and Synechococcus, with Prochlorococcus decreasing from west to east and Synechococcus following the opposite pattern. The analysis of environmental variables (i.e. temperature, salinity and inorganic nutrients) and cell abundances indicates that Prochlorococcus preferred high salinity and nitrate to phosphate ratio. On the contrary, temperature did not seem to play a role in Prochlorococcus distribution as it was numerically important during the whole seasonal cycle. Variability in Synechococcus abundance could not be explained by changes in any environmental variable suggesting that different ecotypes were sampled during the surveys. In particular, our data would indicate

  9. High abundances of cyanomyoviruses in marine ecosystems demonstrate ecological relevance.

    PubMed

    Matteson, Audrey R; Rowe, Janet M; Ponsero, Alise J; Pimentel, Tiana M; Boyd, Philip W; Wilhelm, Steven W

    2013-05-01

    The distribution of cyanomyoviruses was estimated using a quantitative PCR (qPCR) approach that targeted the g20 gene as a proxy for phage. Samples were collected spatially during a > 3000 km transect through the Sargasso Sea and temporally during a gyre-constrained phytoplankton bloom within the southern Pacific Ocean. Cyanomyovirus abundances were lower in the Sargasso Sea than in the southern Pacific Ocean, ranging from 2.75 × 10(3) to 5.15 × 10(4) mL(-1) and correlating with the abundance of their potential hosts (Prochlorococcus and Synechococcus). Cyanomyovirus abundance in the southern Pacific Ocean (east of New Zealand) followed Synechococcus host populations in the system: this included a decrease in g20 gene copies (from 4.3 × 10(5) to 9.6 × 10(3) mL(-1) ) following the demise of a Synechococcus bloom. When compared with direct counts of viruses, observations suggest that the cyanomyoviruses comprised 0.5 to >25% of the total virus community. We estimated daily lysis rates of 0.2-46% of the standing stock of Synechococcus in the Pacific Ocean compared with c. < 1.0% in the Sargasso Sea. In total, our observations confirm this family of viruses is abundant in marine systems and that they are an important source of cyanobacterial mortality.

  10. High abundances of cyanomyoviruses in marine ecosystems demonstrate ecological relevance.

    PubMed

    Matteson, Audrey R; Rowe, Janet M; Ponsero, Alise J; Pimentel, Tiana M; Boyd, Philip W; Wilhelm, Steven W

    2013-05-01

    The distribution of cyanomyoviruses was estimated using a quantitative PCR (qPCR) approach that targeted the g20 gene as a proxy for phage. Samples were collected spatially during a > 3000 km transect through the Sargasso Sea and temporally during a gyre-constrained phytoplankton bloom within the southern Pacific Ocean. Cyanomyovirus abundances were lower in the Sargasso Sea than in the southern Pacific Ocean, ranging from 2.75 × 10(3) to 5.15 × 10(4) mL(-1) and correlating with the abundance of their potential hosts (Prochlorococcus and Synechococcus). Cyanomyovirus abundance in the southern Pacific Ocean (east of New Zealand) followed Synechococcus host populations in the system: this included a decrease in g20 gene copies (from 4.3 × 10(5) to 9.6 × 10(3) mL(-1) ) following the demise of a Synechococcus bloom. When compared with direct counts of viruses, observations suggest that the cyanomyoviruses comprised 0.5 to >25% of the total virus community. We estimated daily lysis rates of 0.2-46% of the standing stock of Synechococcus in the Pacific Ocean compared with c. < 1.0% in the Sargasso Sea. In total, our observations confirm this family of viruses is abundant in marine systems and that they are an important source of cyanobacterial mortality. PMID:23240688

  11. Microclimate Data Improve Predictions of Insect Abundance Models Based on Calibrated Spatiotemporal Temperatures

    PubMed Central

    Rebaudo, François; Faye, Emile; Dangles, Olivier

    2016-01-01

    A large body of literature has recently recognized the role of microclimates in controlling the physiology and ecology of species, yet the relevance of fine-scale climatic data for modeling species performance and distribution remains a matter of debate. Using a 6-year monitoring of three potato moth species, major crop pests in the tropical Andes, we asked whether the spatiotemporal resolution of temperature data affect the predictions of models of moth performance and distribution. For this, we used three different climatic data sets: (i) the WorldClim dataset (global dataset), (ii) air temperature recorded using data loggers (weather station dataset), and (iii) air crop canopy temperature (microclimate dataset). We developed a statistical procedure to calibrate all datasets to monthly and yearly variation in temperatures, while keeping both spatial and temporal variances (air monthly temperature at 1 km² for the WorldClim dataset, air hourly temperature for the weather station, and air minute temperature over 250 m radius disks for the microclimate dataset). Then, we computed pest performances based on these three datasets. Results for temperature ranging from 9 to 11°C revealed discrepancies in the simulation outputs in both survival and development rates depending on the spatiotemporal resolution of the temperature dataset. Temperature and simulated pest performances were then combined into multiple linear regression models to compare predicted vs. field data. We used an additional set of study sites to test the ability of the results of our model to be extrapolated over larger scales. Results showed that the model implemented with microclimatic data best predicted observed pest abundances for our study sites, but was less accurate than the global dataset model when performed at larger scales. Our simulations therefore stress the importance to consider different temperature datasets depending on the issue to be solved in order to accurately predict species

  12. Microclimate Data Improve Predictions of Insect Abundance Models Based on Calibrated Spatiotemporal Temperatures.

    PubMed

    Rebaudo, François; Faye, Emile; Dangles, Olivier

    2016-01-01

    A large body of literature has recently recognized the role of microclimates in controlling the physiology and ecology of species, yet the relevance of fine-scale climatic data for modeling species performance and distribution remains a matter of debate. Using a 6-year monitoring of three potato moth species, major crop pests in the tropical Andes, we asked whether the spatiotemporal resolution of temperature data affect the predictions of models of moth performance and distribution. For this, we used three different climatic data sets: (i) the WorldClim dataset (global dataset), (ii) air temperature recorded using data loggers (weather station dataset), and (iii) air crop canopy temperature (microclimate dataset). We developed a statistical procedure to calibrate all datasets to monthly and yearly variation in temperatures, while keeping both spatial and temporal variances (air monthly temperature at 1 km² for the WorldClim dataset, air hourly temperature for the weather station, and air minute temperature over 250 m radius disks for the microclimate dataset). Then, we computed pest performances based on these three datasets. Results for temperature ranging from 9 to 11°C revealed discrepancies in the simulation outputs in both survival and development rates depending on the spatiotemporal resolution of the temperature dataset. Temperature and simulated pest performances were then combined into multiple linear regression models to compare predicted vs. field data. We used an additional set of study sites to test the ability of the results of our model to be extrapolated over larger scales. Results showed that the model implemented with microclimatic data best predicted observed pest abundances for our study sites, but was less accurate than the global dataset model when performed at larger scales. Our simulations therefore stress the importance to consider different temperature datasets depending on the issue to be solved in order to accurately predict species

  13. High Temperature Solar Cell Development

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Raffaelle, Ryne P.; Merritt, Danielle

    2004-01-01

    The majority of satellites and near-earth probes developed to date have used photovoltaic arrays for power generation. If future mission to probe environments close to the sun will be able to use photovoltaic power, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. In this paper, we derive the optimum bandgap as a function of the operating temperature.

  14. The High Plains Groundwater Availability Study: Abundant Groundwater Doesn't Necessarily Mean Abundant Surface Water

    NASA Astrophysics Data System (ADS)

    Peterson, S. M.; Stanton, J. S.; Flynn, A. T.

    2013-12-01

    The U.S. Geological Survey's Groundwater Resources Program is conducting an assessment of groundwater availability to gain a clearer understanding of the status of the Nation's groundwater resources and the natural and human factors that can affect those resources. Additional goals are to better estimate availability and suitability of those resources in the future for various uses. The High Plains aquifer is a nationally important water resource that underlies about 174,000 square miles in parts of eight western states. The aquifer serves as a primary source of drinking water for approximately 2.3 million people and also sustains more than one quarter of the Nation's agricultural production. In 2000, total water withdrawals of 17.5 billion gallons per day from the aquifer accounted for 20 percent of all groundwater withdrawn in the United States, making it the most intensively pumped aquifer in the Nation. In the Central and Southern High Plains, the aquifer historically had less saturated thickness, and current resource management issues are focused on the availability of water, and reduced ability to irrigate as water levels and well productivity have declined. In contrast, the Northern High Plains aquifer includes the thickest part of the aquifer and a larger saturated thickness than the other parts of the aquifer, and current water resource management issues are related to the interaction of groundwater with surface water and resource management triggered primarily by the availability of surface water. The presentation will cover major components of the High Plains Groundwater Availability Study, including estimating water budget components for the entire High Plains aquifer, building a refined groundwater model for the Northern High Plains aquifer, and using that model to better understand surface- and groundwater interaction and characterize water availability.

  15. Advanced High Temperature Structural Seals

    NASA Astrophysics Data System (ADS)

    Newquist, Charles W.; Verzemnieks, Juris; Keller, Peter C.; Rorabaugh, Michael; Shorey, Mark

    2002-10-01

    This program addresses the development of high temperature structural seals for control surfaces for a new generation of small reusable launch vehicles. Successful development will contribute significantly to the mission goal of reducing launch cost for small, 200 to 300 pound payloads. Development of high temperature seals is mission enabling. For instance, ineffective control surface seals can result in high temperature (3100 F) flows in the elevon area exceeding structural material limits. Longer sealing life will allow use for many missions before replacement, contributing to the reduction of hardware, operation and launch costs.

  16. Advanced High Temperature Structural Seals

    NASA Technical Reports Server (NTRS)

    Newquist, Charles W.; Verzemnieks, Juris; Keller, Peter C.; Rorabaugh, Michael; Shorey, Mark

    2002-01-01

    This program addresses the development of high temperature structural seals for control surfaces for a new generation of small reusable launch vehicles. Successful development will contribute significantly to the mission goal of reducing launch cost for small, 200 to 300 pound payloads. Development of high temperature seals is mission enabling. For instance, ineffective control surface seals can result in high temperature (3100 F) flows in the elevon area exceeding structural material limits. Longer sealing life will allow use for many missions before replacement, contributing to the reduction of hardware, operation and launch costs.

  17. Development of high strength, high temperature ceramics

    NASA Technical Reports Server (NTRS)

    Hall, W. B.

    1982-01-01

    Improvement in the high-pressure turbopumps, both fuel and oxidizer, in the Space Shuttle main engine were considered. The operation of these pumps is limited by temperature restrictions of the metallic components used in these pumps. Ceramic materials that retain strength at high temperatures and appear to be promising candidates for use as turbine blades and impellers are discussed. These high strength materials are sensitive to many related processing parameters such as impurities, sintering aids, reaction aids, particle size, processing temperature, and post thermal treatment. The specific objectives of the study were to: (1) identify and define the processing parameters that affect the properties of Si3N4 ceramic materials, (2) design and assembly equipment required for processing high strength ceramics, (3) design and assemble test apparatus for evaluating the high temperature properties of Si3N4, and (4) conduct a research program of manufacturing and evaluating Si3N4 materials as applicable to rocket engine applications.

  18. High frequency (hourly) variation in vertical distribution and abundance of meroplanktonic larvae in nearshore waters during strong internal tidal forcing

    NASA Astrophysics Data System (ADS)

    Liévana MacTavish, A.; Ladah, L. B.; Lavín, M. F.; Filonov, A.; Tapia, Fabian J.; Leichter, J.

    2016-04-01

    We related the vertical distribution and abundance of nearshore meroplankton at hourly time scales with internal tidal wave events. We proposed that significant changes in plankter abundance would occur across internal tidal fronts, and that surface and bottom strata would respond in opposite fashions. First-mode internal tidal bores propagating in the alongshore direction were detected in water-column currents and baroclinic temperature changes. Surface and bottom currents always flowed in opposite directions, and abrupt flow reversals coincided with large temperature changes during arrival of bores. Crab zoeae and barnacle cyprids were more abundant in the bottom strata, whereas barnacle nauplii showed the opposite pattern. Significant changes in vertical distribution and abundance of target meroplankters occurred across internal tidal fronts, especially for crabs at depth, with surface and bottom organisms responding in opposite fashions. Changes in plankter abundance were significantly correlated with current flows in the strata where they were most abundant. The manner in which plankters were affected (increasing or decreasing abundance) appeared to be modulated by their vertical position within the water column. The significant differences found at the high frequencies of this study, maintained across sampling days, suggest that nearshore meroplankton populations may have greater and more consistent temporal and vertical variability than previously considered.

  19. High temperature turbine engine structure

    DOEpatents

    Boyd, Gary L.

    1990-01-01

    A high temperature turbine engine includes a hybrid ceramic/metallic rotor member having ceramic/metal joint structure. The disclosed joint is able to endure higher temperatures than previously possible, and aids in controlling heat transfer in the rotor member.

  20. A Revision to the Solar System Abundance and Condensation Temperature of Boron from Uncontaminated Falls

    NASA Astrophysics Data System (ADS)

    Zhai, M.; Shaw, D. M.

    1993-07-01

    We requested from participating museum curators interior fragments of chosen falls, never touched by water or other possible sources of B contamination. Thirty six were obtained, crushed, and analyzed for B by PGNAA (prompt gamma- ray neutron activation analyses) at McMaster University and at The National Institute of Standards and Technology. Boron concentrations are close to the sensitivity limit in both laboratories. Results agree well, but with slight systematic differences attributable to blank and background correction factors. Our results (Table 1) are similar to previous measurements on falls [1], but lower than in Antarctic meteorites [2,3], some of which are altered. To calculate the solar system abundance of B, the four carbonaceous chondrite analyses (Table 1) were used as follows. Since CM and CV meteorites contain 48% and 42% matrix [4], if the B ratio of inclusions/matrix is 0.17 [3], then the matrix of the four carbonaceous chondrites averages 0.97 ppm B. Taking the average Si abundance in CI to be 10.64% [5], the calculated solar system abundances from the four carbonaceous chondrites are 23.51, 22.54, 16.95, and 34.20, with a geometric mean of 23.5 B atom/10^6 Si atoms. For comparison, of 18 analyses of interior samples of falls and Antarctic carbonaceous chondrites [1,2,3], 12 have normalized matrix B between 17.6 and 31.4. A composite chondrite atomic composition was calculated for Mg, Na, Li, B, Ga, S, and Zn using their average abundances in H, L, LL, E, and CC meteorites, weighted by their fall frequencies [7] and normalized to Si and the CI abundance [5]. The values show a systematic decrease (Table 2). If this trend is related to volatility [8], then the condensation temperature of B should be between the condensation temperature of Li and Ga, at about 1125 degrees K. If the relative abundances of these elements are similar in the Earth's mantle except for Na [8], then Na appears to show a lower condensation temperature, similar to B. This

  1. Relationship between air temperature and diacid relative abundances in lower troposphere aerosols

    NASA Astrophysics Data System (ADS)

    Sempere, R.; Kawamura, K.; Poggiale, J.

    2013-12-01

    Aerosol samples were collected in western Pacific, Arctic, as well as in urban area in Europe and Japan at differents seasons covering a large range of temperature. They were analyzed for total carbon (TC), water-soluble organic carbon (WSOC) along with the molecular distributions of C2-C10 a, w-dicarboxylic acids, and related polar compounds, mainly, w-oxocarboxylic acids (C2-C9) and a-dicarbonyls (C2-C3). Oxalic acid (C2) was usually the most abundant followed by malonic (C3) and succinic (C4) acids. We observed that relative abundance of oxalic acid (C2) and succinic acid (C4)/ total diacids were correlated with air temperature. These findings suggest that the intensity of photochemical oxidation reactions and thus the variation in sunlight intensity characterized here by air temperature, significantly control the molecular distribution of water-soluble organic compounds during the long-range transport of anthropogenic and/or biogenic higher molecular weight organic compounds.

  2. An Abundant, Highly Conserved Tonoplast Protein in Seeds 1

    PubMed Central

    Johnson, Kenneth D.; Herman, Eliot M.; Chrispeels, Maarten J.

    1989-01-01

    We have isolated the membranes of the protein storage vacuoles (protein bodies) from Phaseolus vulgaris cotyledons and purified an integral membrane protein with Mr 25,000 (TP 25). Antiserum to TP 25 recognizes an abundant polypeptide in the total cell extracts of many different seeds (monocots, dicots, and a gymnosperm), and specifically labels the vacuolar membranes of thin-sectioned soybean embryonic axes and cotyledons. TP 25 was not found in the starchy endosperm of barley and wheat or the seed coats of bean but was present in all seed parts examined that consist of living cells at seed maturity. The abundance of TP 25 was not correlated with the amount of storage protein in seed tissue, and the protein was not found in leaves that accumulate leaf storage protein. On the basis of its abundance, evolutionary conservation, and distribution in the plant, we propose that TP 25 may play a role in maintaining the integrity of the tonoplast during the dehydration/rehydration sequence of seeds. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 PMID:16667102

  3. Advanced High Temperature Structural Seals

    NASA Technical Reports Server (NTRS)

    Newquist, Charles W.; Verzemnieks, Juris; Keller, Peter C.; Shorey, Mark W.; Steinetz, Bruce (Technical Monitor)

    2000-01-01

    This program addresses the development of high temperature structural seals for control surfaces for a new generation of small reusable launch vehicles. Successful development will contribute significantly to the mission goal of reducing launch cost for small, 200 to 300 lb payloads. Development of high temperature seals is mission enabling. For instance, ineffective control surface seals can result in high temperature (3100 F) flows in the elevon area exceeding structural material limits. Longer sealing life will allow use for many missions before replacement, contributing to the reduction of hardware, operation and launch costs. During the first phase of this program the existing launch vehicle control surface sealing concepts were reviewed, the aerothermal environment for a high temperature seal design was analyzed and a mock up of an arc-jet test fixture for evaluating seal concepts was fabricated.

  4. High temperature structural insulating material

    DOEpatents

    Chen, W.Y.

    1984-07-27

    A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800/sup 0/C), low thermal conductivity (below about 0.2 W/m/sup 0/C), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800/sup 0/C, a diameter within the range of 20-200 ..mu..m, and a wall thickness in the range of about 2 to 4 ..mu..m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

  5. High temperature structural insulating material

    DOEpatents

    Chen, Wayne Y.

    1987-01-01

    A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800.degree. C.), low thermal conductivity (below about 0.2 W/m.degree. C.), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800.degree. C., a diameter within the range of 20-200 .mu.m, and a wall thickness in the range of about 2-4 .mu.m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

  6. High temperature structural insulating material

    DOEpatents

    Chen, Wayne Y.

    1987-01-06

    A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800.degree. C.), low thermal conductivity (below about 0.2 W/m.degree. C.), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800.degree. C., a diameter within the range of 20-200 .mu.m, and a wall thickness in the range of about 2-4 .mu.m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

  7. Containerless high temperature calorimeter apparatus

    NASA Technical Reports Server (NTRS)

    Lacy, L. L.; Nisen, D. B. (Inventor)

    1981-01-01

    A calorimeter apparatus for measuring high temperature thermophysical properties of materials is disclosed which includes a containerless heating apparatus in which the specimen is suspended and heated by electron bombardment.

  8. High-temperature structural intermetallics

    SciTech Connect

    Yamaguchi, M.; Inui, H.; Ito, K.

    2000-01-01

    In the last one and a half decades, a great deal of fundamental and developmental research has been made on high-temperature structural intermetallics aiming at the implementation of these intermetallics in aerospace, automotive and land-based applications. These intermetallics include aluminides formed with either titanium, nickel or iron and silicides formed with transition metals. Of these high-temperature intermetallics, TiAl-based alloys with great potential in both aerospace and automotive applications have been attracting particular attention. Recently TiAl turbocharger wheels have finally started being used for turbochargers for commercial passenger cars of a special type. The current status of the research and development of these high-temperature intermetallics is summarized and a perspective on what directions future research and development of high-temperature intermetallics should take is provided.

  9. High temperature current mirror amplifier

    DOEpatents

    Patterson, III, Raymond B.

    1984-05-22

    A high temperature current mirror amplifier having biasing means in the transdiode connection of the input transistor for producing a voltage to maintain the base-collector junction reversed-biased and a current means for maintaining a current through the biasing means at high temperatures so that the base-collector junction of the input transistor remained reversed-biased. For accuracy, a second current mirror is provided with a biasing means and current means on the input leg.

  10. The Very High Temperature Reactor

    SciTech Connect

    Hans D. Gougar; David A. Petti

    2011-06-01

    The High Temperature Reactor (HTR) and Very High Temperature Reactor (VHTR) are types of nuclear power plants that, as the names imply, operate at temperatures above those of the conventional nuclear power plants that currently generate electricity in the US and other countries. Like existing nuclear plants, heat generated from the fission of uranium or plutonium atoms is carried off by a working fluid and can be used generate electricity. The very hot working fluid also enables the VHTR to drive other industrial processes that require high temperatures not achievable by conventional nuclear plants (Figure 1). For this reason, the VHTR is being considered for non-electrical energy applications. The reactor and power conversion system are constructed using special materials that make a core meltdown virtually impossible.

  11. Suzaku Observations of AWM 7 Cluster of Galaxies: Temperatures, Abundances, and Bulk Motions

    NASA Astrophysics Data System (ADS)

    Sato, Kosuke; Matsushita, Kyoko; Ishisaki, Yoshitaka; Yamasaki, Noriko Y.; Ishida, Manabu; Sasaki, Shin; Ohashi, Takaya

    2008-01-01

    We carried out 3 observations of the cluster of galaxies AWM 7, for the central region and 20'-east and 20'-west offset regions, with Suzaku. Temperature and abundance profiles were measured out to 27' simeq 570 h70-1kpc, which corresponded to ˜0.35r180. The temperature of the intra-cluster medium (ICM) slightly decreased from 3.8keV at the center to 3.4keV in the ˜0.35 r180 region, indicating a flatter profile than those in other nearby clusters. The abundance ratio of Si to Fe was almost constant in our observations, while the Mg-to-Fe ratio increased with radius from the cluster center. The O to Fe ratio in the west region showed an increase with radius, while that in the east region was almost flat, though the errors were relatively large. These features suggest that the enrichment process is significantly different between products of type II supernovae (O and Mg) and those by type Ia supernovae (Si and Fe). We also examined the positional shift of the central energy of a He-like Fe-Kα line, in search of possible rotation of the ICM. The 90% upper limit for the line-of-sight velocity difference was derived to be Δ v lesssim 2000kms-1, suggesting that the ellipticity of AWM 7 is rather caused by a recent directional infall of gas along the large-scale filament.

  12. Temperature controlled high voltage regulator

    DOEpatents

    Chiaro, Jr., Peter J.; Schulze, Gerald K.

    2004-04-20

    A temperature controlled high voltage regulator for automatically adjusting the high voltage applied to a radiation detector is described. The regulator is a solid state device that is independent of the attached radiation detector, enabling the regulator to be used by various models of radiation detectors, such as gas flow proportional radiation detectors.

  13. High temperature electronic gain device

    DOEpatents

    McCormick, J. Byron; Depp, Steven W.; Hamilton, Douglas J.; Kerwin, William J.

    1979-01-01

    An integrated thermionic device suitable for use in high temperature, high radiation environments. Cathode and control electrodes are deposited on a first substrate facing an anode on a second substrate. The substrates are sealed to a refractory wall and evacuated to form an integrated triode vacuum tube.

  14. High temperature lightweight foamed cements

    DOEpatents

    Sugama, Toshifumi.

    1989-10-03

    Cement slurries are disclosed which are suitable for use in geothermal wells since they can withstand high temperatures and high pressures. The formulation consists of cement, silica flour, water, a retarder, a foaming agent, a foam stabilizer, and a reinforcing agent. A process for producing these cements is also disclosed. 3 figs.

  15. High temperature lightweight foamed cements

    DOEpatents

    Sugama, Toshifumi

    1989-01-01

    Cement slurries are disclosed which are suitable for use in geothermal wells since they can withstand high temperatures and high pressures. The formulation consists of cement, silica flour, water, a retarder, a foaming agent, a foam stabilizer, and a reinforcing agent. A process for producing these cements is also disclosed.

  16. High temperature Seebeck coefficient metrology

    SciTech Connect

    Martin, J.; Tritt, T.; Uher, C.

    2010-12-15

    We present an overview of the challenges and practices of thermoelectric metrology on bulk materials at high temperature (300 to 1300 K). The Seebeck coefficient, when combined with thermal and electrical conductivity, is an essential property measurement for evaluating the potential performance of novel thermoelectric materials. However, there is some question as to which measurement technique(s) provides the most accurate determination of the Seebeck coefficient at high temperature. This has led to the implementation of nonideal practices that have further complicated the confirmation of reported high ZT materials. To ensure meaningful interlaboratory comparison of data, thermoelectric measurements must be reliable, accurate, and consistent. This article will summarize and compare the relevant measurement techniques and apparatus designs required to effectively manage uncertainty, while also providing a reference resource of previous advances in high temperature thermoelectric metrology.

  17. Gallium phosphide high temperature diodes

    NASA Technical Reports Server (NTRS)

    Chaffin, R. J.; Dawson, L. R.

    1981-01-01

    High temperature (300 C) diodes for geothermal and other energy applications were developed. A comparison of reverse leakage currents of Si, GaAs, and GaP was made. Diodes made from GaP should be usable to 500 C. A Liquid Phase Epitaxy (LPE) process for producing high quality, grown junction GaP diodes is described. This process uses low vapor pressure Mg as a dopant which allows multiple boat growth in the same LPE run. These LPE wafers were cut into die and metallized to make the diodes. These diodes produce leakage currents below ten to the -9th power A/sq cm at 400 C while exhibiting good high temperature rectification characteristics. High temperature life test data is presented which shows exceptional stability of the V-I characteristics.

  18. Temperature optimization of high con

    NASA Astrophysics Data System (ADS)

    Sabry, M.

    2016-06-01

    Active cooling is essential for solar cells operating under high optical concentration ratios. A system comprises four solar cells that are in thermal contact on top of a copper tube is proposed. Water is flowing inside the tube in order to reduce solar cells temperature for increasing their performance. Computational Fluid Dynamics (CFD) simulation of such system has been performed in order to investigate the effect of water flow rate, tube internal diameter, and convective heat transfer coefficient on the temperature of the solar cells. It is found that increasing convective heat transfer coefficient has a significant effect on reducing solar cells temperatures operating at low flow rates and high optical concentration ratios. Also, a further increase of water flow rate has no effect on reducing cells temperatures.

  19. Body temperatures of modern and extinct vertebrates from 13C-18O bond abundances in bioapatite

    PubMed Central

    Eagle, Robert A.; Schauble, Edwin A.; Tripati, Aradhna K.; Tütken, Thomas; Hulbert, Richard C.; Eiler, John M.

    2010-01-01

    The stable isotope compositions of biologically precipitated apatite in bone, teeth, and scales are widely used to obtain information on the diet, behavior, and physiology of extinct organisms and to reconstruct past climate. Here we report the application of a new type of geochemical measurement to bioapatite, a “clumped-isotope” paleothermometer, based on the thermodynamically driven preference for 13C and 18O to bond with each other within carbonate ions in the bioapatite crystal lattice. This effect is dependent on temperature but, unlike conventional stable isotope paleothermometers, is independent from the isotopic composition of water from which the mineral formed. We show that the abundance of 13C-18O bonds in the carbonate component of tooth bioapatite from modern specimens decreases with increasing body temperature of the animal, following a relationship between isotope “clumping” and temperature that is statistically indistinguishable from inorganic calcite. This result is in agreement with a theoretical model of isotopic ordering in carbonate ion groups in apatite and calcite. This thermometer constrains body temperatures of bioapatite-producing organisms with an accuracy of 1–2 °C. Analyses of fossilized tooth enamel of both Pleistocene and Miocene age yielded temperatures within error of those derived from similar modern taxa. Clumped-isotope analysis of bioapatite represents a new approach in the study of the thermophysiology of extinct species, allowing the first direct measurement of their body temperatures. It will also open new avenues in the study of paleoclimate, as the measurement of clumped isotopes in phosphorites and fossils has the potential to reconstruct environmental temperatures. PMID:20498092

  20. Containerless high-temperature calorimeter

    NASA Technical Reports Server (NTRS)

    Lacy, L. L.; Nisen, D. B.; Robinson, M. B.

    1979-01-01

    Samples are heated by electron bombardment in high-temperature calorimeter that operates from 1,000 to 3,600 C yet consumes less that 100 watts at temperatures less than 2,500 C. Contamination of samples is kept to minimum by suspending them from wire in vacuum chamber. Various sample slopes such as wires, dishs, spheres, rods, or irregular bodies can be accommodated and only about 100 nq of samples are needed for accurate measurements.

  1. Bellows high temperature cycle life

    SciTech Connect

    Broyles, R.K.

    1995-11-01

    In most cases, the bellows elements in an expansion joint are separated or insulated from the hot flow stream and have an actual bellows metal temperature (ABMT) that is much lower than the flow stream temperature. However, when the bellows are externally insulated or when the expansion joint is located inside a hot vessel, the ABMT can be very high. For these situations, the effects of temperature on bellows cycle life should be carefully considered. The design equations presented in the Standards of the expansion Joint Manufacturers Association (EJMA), ASME Section 8, Division 1, and ASME B31.3 do not currently provide cycle life equations or temperature correction factors for bellows operating in the creep temperature range. Therefore, a method is proposed which is specifically tailored to bellows for the estimation of high temperature cycle life based upon available test results. Data is also presented which demonstrates the effect of temperatures above and below 800 F on the cycle life of various bellows materials.

  2. Effect of temperature and zooplankton abundance on growth and survival of larval threadfin shad

    USGS Publications Warehouse

    Betsill, R.K.; Van Den Avyle, M.J.

    1997-01-01

    As a test of the match-mismatch hypothesis, we examined the effects of prey availability and water temperature on growth and survival of weekly cohorts of larval threadfin shad Dorosoma petenense in J. Strom Thurmond Reservoir, Georgia-South Carolina. Hatching dates were estimated from otolith increments, and availability of prey was estimated from the abundance of zooplankton size-classes commonly eaten by larval threadfin shad. Growth rates of 31 cohorts ranged from 0.39 to 0.78 mm/d, demonstrating the potential for stage-duration effects on cohort survival. Daily growth rate was related to water temperature and prey availability for larvae up to 21 d old. Growth increased linearly with water temperature up to 28??C, but the relation between growth and prey availability was more complex. Growth rate increased with prey density up to 160-290 organisms/L; at higher densities, growth rate decreased or was unchanged. Cohort survival ranged from 0.65 to 0.96 (per millimeter increase in length) and was significantly correlated with water temperature and growth rate but not with prey availability.

  3. High Temperature Transparent Furnace Development

    NASA Technical Reports Server (NTRS)

    Bates, Stephen C.

    1997-01-01

    This report describes the use of novel techniques for heat containment that could be used to build a high temperature transparent furnace. The primary objective of the work was to experimentally demonstrate transparent furnace operation at 1200 C. Secondary objectives were to understand furnace operation and furnace component specification to enable the design and construction of a low power prototype furnace for delivery to NASA in a follow-up project. The basic approach of the research was to couple high temperature component design with simple concept demonstration experiments that modify a commercially available transparent furnace rated at lower temperature. A detailed energy balance of the operating transparent furnace was performed, calculating heat losses through the furnace components as a result of conduction, radiation, and convection. The transparent furnace shells and furnace components were redesigned to permit furnace operation at at least 1200 C. Techniques were developed that are expected to lead to significantly improved heat containment compared with current transparent furnaces. The design of a thermal profile in a multizone high temperature transparent furnace design was also addressed. Experiments were performed to verify the energy balance analysis, to demonstrate some of the major furnace improvement techniques developed, and to demonstrate the overall feasibility of a high temperature transparent furnace. The important objective of the research was achieved: to demonstrate the feasibility of operating a transparent furnace at 1200 C.

  4. High-Temperature Optical Sensor

    NASA Technical Reports Server (NTRS)

    Adamovsky, Grigory; Juergens, Jeffrey R.; Varga, Donald J.; Floyd, Bertram M.

    2010-01-01

    A high-temperature optical sensor (see Figure 1) has been developed that can operate at temperatures up to 1,000 C. The sensor development process consists of two parts: packaging of a fiber Bragg grating into a housing that allows a more sturdy thermally stable device, and a technological process to which the device is subjected to in order to meet environmental requirements of several hundred C. This technology uses a newly discovered phenomenon of the formation of thermally stable secondary Bragg gratings in communication-grade fibers at high temperatures to construct robust, optical, high-temperature sensors. Testing and performance evaluation (see Figure 2) of packaged sensors demonstrated operability of the devices at 1,000 C for several hundred hours, and during numerous thermal cycling from 400 to 800 C with different heating rates. The technology significantly extends applicability of optical sensors to high-temperature environments including ground testing of engines, flight propulsion control, thermal protection monitoring of launch vehicles, etc. It may also find applications in such non-aerospace arenas as monitoring of nuclear reactors, furnaces, chemical processes, and other hightemperature environments where other measurement techniques are either unreliable, dangerous, undesirable, or unavailable.

  5. High temperature current mirror amplifier

    DOEpatents

    Patterson, R.B. III.

    1984-05-22

    Disclosed is a high temperature current mirror amplifier having biasing means in the transdiode connection of the input transistor for producing a voltage to maintain the base-collector junction reversed-biased and a current means for maintaining a current through the biasing means at high temperatures so that the base-collector junction of the input transistor remained reversed-biased. For accuracy, a second current mirror is provided with a biasing means and current means on the input leg. 2 figs.

  6. "Green" High-Temperature Polymers

    NASA Technical Reports Server (NTRS)

    Meador, Michael A.

    1998-01-01

    PMR-15 is a processable, high-temperature polymer developed at the NASA Lewis Research Center in the 1970's principally for aeropropulsion applications. Use of fiber-reinforced polymer matrix composites in these applications can lead to substantial weight savings, thereby leading to improved fuel economy, increased passenger and payload capacity, and better maneuverability. PMR-15 is used fairly extensively in military and commercial aircraft engines components seeing service temperatures as high as 500 F (260 C), such as the outer bypass duct for the F-404 engine. The current world-wide market for PMR-15 materials (resins, adhesives, and composites) is on the order of $6 to 10 million annually.

  7. High Temperature Polymer Matrix Composites

    NASA Technical Reports Server (NTRS)

    1985-01-01

    These are the proceedings of the High Temperature Polymer Matrix Composites Conference held at the NASA Lewis Research Center on March 16 to 18, 1983. The purpose of the conference is to provide scientists and engineers working in the field of high temperature polymer matrix composites an opportunity to review, exchange, and assess the latest developments in this rapidly expanding area of materials technology. Technical papers are presented in the following areas: (1) matrix development; (2) adhesive development; (3) characterization; (4) environmental effects; and (5) applications.

  8. High temperature superconductor current leads

    DOEpatents

    Hull, J.R.; Poeppel, R.B.

    1995-06-20

    An electrical lead is disclosed having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths. 9 figs.

  9. High temperature superconductor current leads

    DOEpatents

    Hull, John R.; Poeppel, Roger B.

    1995-01-01

    An electrical lead having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths.

  10. What Are the Sources of Solar Energetic Particles? Element Abundances and Source Plasma Temperatures

    NASA Astrophysics Data System (ADS)

    Reames, Donald V.

    2015-11-01

    We have spent 50 years in heated discussion over which populations of solar energetic particles (SEPs) are accelerated at flares and which by shock waves driven out from the Sun by coronal mass ejections (CMEs). The association of the large "gradual" SEP events with shock acceleration is supported by the extensive spatial distribution of SEPs and by the delayed acceleration of the particles. Recent STEREO observations have begun to show that the particle onset times correspond to the observed time of arrival of the shock on the observer's magnetic flux tube and that the SEP intensities are related to the local shock speed. The relative abundances of the elements in these gradual events are a measure of those in the ambient solar corona, differing from those in the photosphere by a widely-observed function of the first ionization potential (FIP) of the elements. SEP events we call "impulsive", the traditional "3He-rich" events with enhanced heavy-element abundances, are associated with type III radio bursts, flares, and narrow CMEs; they selectively populate flux tubes that thread a localized source, and they are fit to new particle-in-cell models of magnetic reconnection on open field lines as found in solar jets. These models help explain the strong enhancements seen in heavy elements as a power (of 2-8) in the mass-to-charge ratio A/Q throughout the periodic table from He to Pb. A study of the temperature dependence of A/Q shows that the source plasma in impulsive SEP events must lie in the range of 2-4 MK to explain the pattern of abundances. This is much lower than the temperatures of >10 MK seen on closed loops in solar flares. Recent studies of A/Q-dependent enhancements or suppressions from scattering during transport show source plasma temperatures in gradual SEP events to be 0.8-1.6 MK in 69 % of the events, i.e. coronal plasma; 24 % of the events show reaccelerated impulsive-event material.

  11. HHSMT observations of the Venusian mesospheric temperature, winds, and CO abundance around the MESSENGER flyby

    NASA Astrophysics Data System (ADS)

    Rengel, Miriam; Hartogh, Paul; Jarchow, Christopher

    2008-11-01

    We present submillimeter observations of 12CO J=3-2 and 2-1, and 13CO J=2-1 lines of the Venusian mesosphere and lower thermosphere with the Heinrich Hertz Submillimeter Telescope (HHSMT) taken around the second MESSENGER flyby of Venus on 5 June 2007. The observations cover a range of Venus solar elongations with different fractional disk illuminations. Preliminary results like temperature and CO abundance profiles are presented. These data are part of a coordinated observational campaign in support of the ESA Venus Express mission. Furthermore, this study attempts to contribute to cross-calibrate space- and ground-based observations, to constrain radiative transfer and retrieval algorithms for planetary atmospheres, and to a more thorough understanding of the global patters of circulation of the Venusian atmosphere.

  12. A solar high temperature kiln

    NASA Astrophysics Data System (ADS)

    Huettenhoelscher, N.; Bergmann, K.

    1981-11-01

    The feasibility of using solar energy in developing countries for baking ceramic construction materials was investigated. The solar high temperature kiln is described. It uses two parabolic concentrators which direct available radiation into the baking chamber. The Sun tracker has only one axis. Preliminary test results with the prototype kiln were satisfactory.

  13. High temperature turbine engine structure

    DOEpatents

    Boyd, Gary L.

    1991-01-01

    A high temperature turbine engine includes a rotor portion having axially stacked adjacent ceramic rotor parts. A ceramic/ceramic joint structure transmits torque between the rotor parts while maintaining coaxial alignment and axially spaced mutually parallel relation thereof despite thermal and centrifugal cycling.

  14. High-Temperature Vibration Damper

    NASA Technical Reports Server (NTRS)

    Clarke, Alan; Litwin, Joel; Krauss, Harold

    1987-01-01

    Device for damping vibrations functions at temperatures up to 400 degrees F. Dampens vibrational torque loads as high as 1,000 lb-in. but compact enough to be part of helicopter rotor hub. Rotary damper absorbs energy from vibrating rod, dissipating it in turbulent motion of viscous hydraulic fluid forced by moving vanes through small orifices.

  15. High Precision Abundances of the Old Solar Twin HIP 102152: Insights on Li Depletion from the Oldest Sun

    NASA Astrophysics Data System (ADS)

    Monroe, TalaWanda R.; Meléndez, Jorge; Ramírez, Iván; Yong, David; Bergemann, Maria; Asplund, Martin; Bedell, Megan; Tucci Maia, Marcelo; Bean, Jacob; Lind, Karin; Alves-Brito, Alan; Casagrande, Luca; Castro, Matthieu; do Nascimento, José-Dias; Bazot, Michael; Freitas, Fabrício C.

    2013-09-01

    We present the first detailed chemical abundance analysis of the old 8.2 Gyr solar twin, HIP 102152. We derive differential abundances of 21 elements relative to the Sun with precisions as high as 0.004 dex (lsim1%), using ultra high-resolution (R = 110,000), high S/N UVES spectra obtained on the 8.2 m Very Large Telescope. Our determined metallicity of HIP 102152 is [Fe/H] = -0.013 ± 0.004. The atmospheric parameters of the star were determined to be 54 K cooler than the Sun, 0.09 dex lower in surface gravity, and a microturbulence identical to our derived solar value. Elemental abundance ratios examined versus dust condensation temperature reveal a solar abundance pattern for this star, in contrast to most solar twins. The abundance pattern of HIP 102152 appears to be the most similar to solar of any known solar twin. Abundances of the younger, 2.9 Gyr solar twin, 18 Sco, were also determined from UVES spectra to serve as a comparison for HIP 102152. The solar chemical pattern of HIP 102152 makes it a potential candidate to host terrestrial planets, which is reinforced by the lack of giant planets in its terrestrial planet region. The following non-local thermodynamic equilibrium Li abundances were obtained for HIP 102152, 18 Sco, and the Sun: log epsilon (Li) = 0.48 ± 0.07, 1.62 ± 0.02, and 1.07 ± 0.02, respectively. The Li abundance of HIP 102152 is the lowest reported to date for a solar twin, and allows us to consider an emerging, tightly constrained Li-age trend for solar twin stars. Based on observations obtained at the European Southern Observatory (observing programs 083.D-0871 and 188.C-0265).

  16. HIGH PRECISION ABUNDANCES OF THE OLD SOLAR TWIN HIP 102152: INSIGHTS ON Li DEPLETION FROM THE OLDEST SUN

    SciTech Connect

    Monroe, TalaWanda R.; Melendez, Jorge; Tucci Maia, Marcelo; Freitas, Fabricio C.; Yong, David; Asplund, Martin; Alves-Brito, Alan; Casagrande, Luca; Bergemann, Maria; Bedell, Megan; Bean, Jacob; Lind, Karin; Castro, Matthieu; Do Nascimento, Jose-Dias; Bazot, Michael

    2013-09-10

    We present the first detailed chemical abundance analysis of the old 8.2 Gyr solar twin, HIP 102152. We derive differential abundances of 21 elements relative to the Sun with precisions as high as 0.004 dex ({approx}<1%), using ultra high-resolution (R = 110,000), high S/N UVES spectra obtained on the 8.2 m Very Large Telescope. Our determined metallicity of HIP 102152 is [Fe/H] = -0.013 {+-} 0.004. The atmospheric parameters of the star were determined to be 54 K cooler than the Sun, 0.09 dex lower in surface gravity, and a microturbulence identical to our derived solar value. Elemental abundance ratios examined versus dust condensation temperature reveal a solar abundance pattern for this star, in contrast to most solar twins. The abundance pattern of HIP 102152 appears to be the most similar to solar of any known solar twin. Abundances of the younger, 2.9 Gyr solar twin, 18 Sco, were also determined from UVES spectra to serve as a comparison for HIP 102152. The solar chemical pattern of HIP 102152 makes it a potential candidate to host terrestrial planets, which is reinforced by the lack of giant planets in its terrestrial planet region. The following non-local thermodynamic equilibrium Li abundances were obtained for HIP 102152, 18 Sco, and the Sun: log {epsilon} (Li) = 0.48 {+-} 0.07, 1.62 {+-} 0.02, and 1.07 {+-} 0.02, respectively. The Li abundance of HIP 102152 is the lowest reported to date for a solar twin, and allows us to consider an emerging, tightly constrained Li-age trend for solar twin stars.

  17. High temperature, high power piezoelectric composite transducers.

    PubMed

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-08-08

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  18. High Temperature, High Power Piezoelectric Composite Transducers

    PubMed Central

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  19. High temperature, high power piezoelectric composite transducers.

    PubMed

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  20. High-temperature containerless calorimeter

    NASA Technical Reports Server (NTRS)

    Robinson, M. B.; Lacy, L. L.

    1985-01-01

    A high-temperature (greater than 1500 K) containerless calorimeter is described and its usefulness demonstrated. The calorimeter uses the technique of omnidirectional electron bombardment of pendant drops to achieve an isothermal test environment. The small heat input into the sample (i.e., 15-50 W) can be controlled and measured. The apparatus can be used to determine the total hemispherical emissivity, specific heat, heat of fusion, surface tension, and equilibrium melting temperature of small molten drops in the temperature range of 1500 to 3500 K. The total hemispherical emissivity and specific heat of pure niobium and two alloys of niobium-germanium have been measured in the temperature range of 1700 to 2400 K. As reported in the literature, the total hemispherical emissivity varied as a function of temperature. However, specific heat values for both the pure metal and alloys seem to be independent of temperature. Specific heat for the liquid alloy phase was also measured and compared to the solid phase.

  1. Solute strengthening at high temperatures

    NASA Astrophysics Data System (ADS)

    Leyson, G. P. M.; Curtin, W. A.

    2016-08-01

    The high temperature behavior of solute strengthening has previously been treated approximately using various scaling arguments, resulting in logarithmic and power-law scalings for the stress-dependent energy barrier Δ E(τ ) versus stress τ. Here, a parameter-free solute strengthening model is extended to high temperatures/low stresses without any a priori assumptions on the functional form of Δ E(τ ) . The new model predicts that the well-established low-temperature, with energy barrier Δ {{E}\\text{b}} and zero temperature flow stress {τy0} , transitions to a near-logarithmic form for stresses in the regime 0.2<τ /{τy0}≤slant 0.5 and then transitions to a power-law form at even lower stresses τ /{τy0}<0.03 . Δ {{E}\\text{b}} and {τy0} remains as the reference energy and stress scales over the entire range of stresses. The model is applied to literature data on solution strengthening in Cu alloys and captures the experimental results quantitatively and qualitatively. Most importantly, the model accurately captures the transition in strength from the low-temperature to intermediate-temperature and the associated transition for the activation volume. Overall, the present analysis unifies the different qualitative models in the literature and, when coupled with the previous parameter-free solute strengthening model, provides a single predictive model for solute strengthening as a function of composition, temperature, and strain rate over the full range of practical utility.

  2. High-temperature Ionization in Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Desch, Steven J.; Turner, Neal J.

    2015-10-01

    We calculate the abundances of electrons and ions in the hot (≳500 K), dusty parts of protoplanetary disks, treating for the first time the effects of thermionic and ion emission from the dust grains. High-temperature ionization modeling has involved simply assuming that alkali elements such as potassium occur as gas-phase atoms and are collisionally ionized following the Saha equation. We show that the Saha equation often does not hold, because free charges are produced by thermionic and ion emission and destroyed when they stick to grain surfaces. This means the ionization state depends not on the first ionization potential of the alkali atoms, but rather on the grains’ work functions. The charged species’ abundances typically rise abruptly above about 800 K, with little qualitative dependence on the work function, gas density, or dust-to-gas mass ratio. Applying our results, we find that protoplanetary disks’ dead zone, where high diffusivities stifle magnetorotational turbulence, has its inner edge located where the temperature exceeds a threshold value ≈1000 K. The threshold is set by ambipolar diffusion except at the highest densities, where it is set by Ohmic resistivity. We find that the disk gas can be diffusively loaded onto the stellar magnetosphere at temperatures below a similar threshold. We investigate whether the “short-circuit” instability of current sheets can operate in disks and find that it cannot, or works only in a narrow range of conditions; it appears not to be the chondrule formation mechanism. We also suggest that thermionic emission is important for determining the rate of Ohmic heating in hot Jupiters.

  3. HIGH-TEMPERATURE IONIZATION IN PROTOPLANETARY DISKS

    SciTech Connect

    Desch, Steven J.; Turner, Neal J.

    2015-10-01

    We calculate the abundances of electrons and ions in the hot (≳500 K), dusty parts of protoplanetary disks, treating for the first time the effects of thermionic and ion emission from the dust grains. High-temperature ionization modeling has involved simply assuming that alkali elements such as potassium occur as gas-phase atoms and are collisionally ionized following the Saha equation. We show that the Saha equation often does not hold, because free charges are produced by thermionic and ion emission and destroyed when they stick to grain surfaces. This means the ionization state depends not on the first ionization potential of the alkali atoms, but rather on the grains’ work functions. The charged species’ abundances typically rise abruptly above about 800 K, with little qualitative dependence on the work function, gas density, or dust-to-gas mass ratio. Applying our results, we find that protoplanetary disks’ dead zone, where high diffusivities stifle magnetorotational turbulence, has its inner edge located where the temperature exceeds a threshold value ≈1000 K. The threshold is set by ambipolar diffusion except at the highest densities, where it is set by Ohmic resistivity. We find that the disk gas can be diffusively loaded onto the stellar magnetosphere at temperatures below a similar threshold. We investigate whether the “short-circuit” instability of current sheets can operate in disks and find that it cannot, or works only in a narrow range of conditions; it appears not to be the chondrule formation mechanism. We also suggest that thermionic emission is important for determining the rate of Ohmic heating in hot Jupiters.

  4. High temperature strain gage evaluation

    NASA Technical Reports Server (NTRS)

    Gonzalez, J. I.

    1977-01-01

    The structural thermal test of an advanced ramjet missile section required strain measurements as high as 922 K (1200 F). Since there is relatively little experience in the use of strain gages above the 700-755 K (800-900 F) level, a program was initiated to select and evaluate the best available gage. Candidate gages suitable for measurements up to 922 K (1200 F) were selected. This involved the determination of their operating characteristics, availability, cost, installation aspects, etc. The evaluation involved the following tests: strain as a function of load at room temperature and apparent strain as a function of temperature.

  5. High temperature sorbents for oxygen

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K. (Inventor)

    1994-01-01

    A sorbent capable of removing trace amounts of oxygen (ppt) from a gas stream at a high temperature above 200 C comprising a porous alumina silicate support, such as zeolite, containing from 1 to 10 percent by weight of ion exchanged transition metal, such as copper or cobalt ions, and 0.05 to 1.0 percent by weight of an activator selected from a platinum group metal such as platinum is described. The activation temperature, oxygen sorption, and reducibility are all improved by the presence of the platinum activator.

  6. High Temperature Sorbents for Oxygen

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K. (Inventor)

    1996-01-01

    A sorbent capable of removing trace amounts of oxygen (ppt) from a gas stream at a high temperature above 200 C is introduced. The sorbent comprises a porous alumina silicate support such as zeolite containing from 1 to 10 percent by weight of ion exchanged transition metal such as copper or cobalt ions and 0.05 to 1.0 percent by weight of an activator selected from a platinum group metal such as platinum. The activation temperature, oxygen sorption and reducibility are all improved by the presence of the platinum activator.

  7. High temperature thermoelectric energy conversion

    NASA Technical Reports Server (NTRS)

    Wood, Charles

    1987-01-01

    The theory and current status of materials research for high-temperature thermoelectric energy conversion are reviewed. Semiconductors are shown to be the preferred class of materials for this application. Optimization of the figure of merit of both broadband and narrow-band semiconductors is discussed as a function of temperature. Phonon scattering mechanisms are discussed, and basic material guidelines are given for reduction of thermal conductivity. Two general classes of materials show promise for high temperature figure of merit (Z) values, namely the rare earth chalcogenides and the boron-rich borides. The electronic transport properties of the rare earth chalcogenides are explicable on the basis of degenerate or partially degenerate n-type semiconductors. Boron and boron-rich borides exhibit p-type hopping conductivity, with detailed explanations proposed for the transport differing from compound to compound. Some discussion is presented on the reasons for the low thermal conductivities in these materials. Also, ZTs greater than one appear to have been realized at high temperature in many of these compounds.

  8. High Temperature Transfer Molding Resins

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

    2000-01-01

    High temperature resins containing phenylethynyl groups that are processable by transfer molding have been prepared. These phenylethynyl containing oligomers were prepared from aromatic diamines containing phenylethynyl groups and various ratios of phthalic anhydride and 4-phenylethynlphthalic anhydride in glacial acetic acid to form a mixture of imide compounds in one step. This synthetic approach is advantageous since the products are a mixture of compounds and consequently exhibit a relatively low melting temperature. In addition, these materials exhibit low melt viscosities which are stable for several hours at 210-275 C, and since the thermal reaction of the phenylethynyl group does not occur to any appreciable extent at temperatures below 300 C, these materials have a broad processing window. Upon thermal cure at approximately 300-350 C, the phenylethynyl groups react to provide a crosslinked resin system. These new materials exhibit excellent properties and are potentially useful as adhesives, coatings, films, moldings and composite matrices.

  9. High temperature seal test rig

    NASA Technical Reports Server (NTRS)

    Addy, Harold E., Jr.

    1994-01-01

    The High Temperature Seals Test Rig Program at NASA's Lewis Research Center is a joint effort involving three separate federal government agencies. Testing has been underway at Lewis in this test rig since April, 1993. The rig was designed to run tests at temperatures to 800 F at pressures to 200 psia or at temperatures to 1300 to 1500 F at pressures to 65 psia. It was designed to run at speeds of up to 50,000 rpm which, for a 5.1 inch diameter disk, is a surface speed of about 1100 ft./sec. The rig was designed to allow easy replacement of the disks as well as the seals such that different disk materials and coatings may be tested.

  10. High-temperature battery calorimeter

    SciTech Connect

    Hansen, L.D.; Hart, R.H.; Chen, D.M.; Gibbard, H.F.

    1982-04-01

    A battery calorimeter was built for the measurement of thermal energy generation of high-temperature lithium--aluminum/iron sulfide battery cells, which are under development for electric vehicle propulsion and other energy storage applications. The calorimeter was designed with a temperature range of 400 /sup 0/--500 /sup 0/C, a detection limit of 1 mW, and an upper limit of heat flow of 50 W. The results of measurements on 200-Ah LiAl/FeS cells were in excellent agreement with the predictions of thermodynamic calculations based on precise measurements of the total cell polarization and the temperature coefficient of the emf. Details of the construction and operation principles of this calorimeter are given.

  11. Performance of Baited Underwater Video: Does It Underestimate Abundance at High Population Densities?

    PubMed Central

    Stobart, Ben; Díaz, David; Álvarez, Federico; Alonso, Cristina; Mallol, Sandra; Goñi, Raquel

    2015-01-01

    Video survey techniques are now commonly used to estimate animal abundance under the assumption that estimates relate to true abundance, a key property needed to make video a valid survey tool. Using the spiny lobster Palinurus elephas as our model organism, we evaluate the effectiveness of baited underwater video (BUV) for estimating abundance in areas with widely different population density. We test three BUV abundance metrics and compare the results with an independently obtained abundance index from trammel-net surveys (Trammel). Video metrics used to estimate relative abundance include a value for total number of individuals per recording (TotN), the traditional maximum number of fish observed in a single video frame (MaxN), and the recently suggested alternative, the average of the mean MaxN from 5-minute periods throughout the duration of the recording (MeanN). This is the first video study of a wild population to include an estimate for TotN. Comparison of TotN with the other two BUV relative abundance metrics demonstrates that both of the latter lack resolution at high population densities. In spite of this, the three BUV metrics tested, as well as the independent estimate Trammel, distinguished high density areas from low density areas. Thus they could all be used to identify areas of differing population density, but MaxN and MeanN would not be appropriate metrics for studies aimed at documenting increases in abundance, such as those conducted to assess marine protected area effectiveness, as they are prone to sampling saturation. We also demonstrate that time of first arrival (T1) is highly correlated with all of the abundance indices; suggesting T1 may be a potentially useful index of abundance. However, these relationships require further investigation as our data suggests T1 may not adequately represent lobster abundance in areas of high density. PMID:26010738

  12. Performance of baited underwater video: does it underestimate abundance at high population densities?

    PubMed

    Stobart, Ben; Díaz, David; Álvarez, Federico; Alonso, Cristina; Mallol, Sandra; Goñi, Raquel

    2015-01-01

    Video survey techniques are now commonly used to estimate animal abundance under the assumption that estimates relate to true abundance, a key property needed to make video a valid survey tool. Using the spiny lobster Palinurus elephas as our model organism, we evaluate the effectiveness of baited underwater video (BUV) for estimating abundance in areas with widely different population density. We test three BUV abundance metrics and compare the results with an independently obtained abundance index from trammel-net surveys (Trammel). Video metrics used to estimate relative abundance include a value for total number of individuals per recording (TotN), the traditional maximum number of fish observed in a single video frame (MaxN), and the recently suggested alternative, the average of the mean MaxN from 5-minute periods throughout the duration of the recording (MeanN). This is the first video study of a wild population to include an estimate for TotN. Comparison of TotN with the other two BUV relative abundance metrics demonstrates that both of the latter lack resolution at high population densities. In spite of this, the three BUV metrics tested, as well as the independent estimate Trammel, distinguished high density areas from low density areas. Thus they could all be used to identify areas of differing population density, but MaxN and MeanN would not be appropriate metrics for studies aimed at documenting increases in abundance, such as those conducted to assess marine protected area effectiveness, as they are prone to sampling saturation. We also demonstrate that time of first arrival (T1) is highly correlated with all of the abundance indices; suggesting T1 may be a potentially useful index of abundance. However, these relationships require further investigation as our data suggests T1 may not adequately represent lobster abundance in areas of high density.

  13. Performance of baited underwater video: does it underestimate abundance at high population densities?

    PubMed

    Stobart, Ben; Díaz, David; Álvarez, Federico; Alonso, Cristina; Mallol, Sandra; Goñi, Raquel

    2015-01-01

    Video survey techniques are now commonly used to estimate animal abundance under the assumption that estimates relate to true abundance, a key property needed to make video a valid survey tool. Using the spiny lobster Palinurus elephas as our model organism, we evaluate the effectiveness of baited underwater video (BUV) for estimating abundance in areas with widely different population density. We test three BUV abundance metrics and compare the results with an independently obtained abundance index from trammel-net surveys (Trammel). Video metrics used to estimate relative abundance include a value for total number of individuals per recording (TotN), the traditional maximum number of fish observed in a single video frame (MaxN), and the recently suggested alternative, the average of the mean MaxN from 5-minute periods throughout the duration of the recording (MeanN). This is the first video study of a wild population to include an estimate for TotN. Comparison of TotN with the other two BUV relative abundance metrics demonstrates that both of the latter lack resolution at high population densities. In spite of this, the three BUV metrics tested, as well as the independent estimate Trammel, distinguished high density areas from low density areas. Thus they could all be used to identify areas of differing population density, but MaxN and MeanN would not be appropriate metrics for studies aimed at documenting increases in abundance, such as those conducted to assess marine protected area effectiveness, as they are prone to sampling saturation. We also demonstrate that time of first arrival (T1) is highly correlated with all of the abundance indices; suggesting T1 may be a potentially useful index of abundance. However, these relationships require further investigation as our data suggests T1 may not adequately represent lobster abundance in areas of high density. PMID:26010738

  14. NSTX High Temperature Sensor Systems

    SciTech Connect

    B.McCormack; H.W. Kugel; P. Goranson; R. Kaita; et al

    1999-11-01

    The design of the more than 300 in-vessel sensor systems for the National Spherical Torus Experiment (NSTX) has encountered several challenging fusion reactor diagnostic issues involving high temperatures and space constraints. This has resulted in unique miniature, high temperature in-vessel sensor systems mounted in small spaces behind plasma facing armor tiles, and they are prototypical of possible high power reactor first-wall applications. In the Center Stack, Divertor, Passive Plate, and vessel wall regions, the small magnetic sensors, large magnetic sensors, flux loops, Rogowski Coils, thermocouples, and Langmuir Probes are qualified for 600 degrees C operation. This rating will accommodate both peak rear-face graphite tile temperatures during operations and the 350 degrees C bake-out conditions. Similar sensor systems including flux loops, on other vacuum vessel regions are qualified for 350 degrees C operation. Cabling from the sensors embedded in the graphite tiles follows narrow routes to exit the vessel. The detailed sensor design and installation methods of these diagnostic systems developed for high-powered ST operation are discussed.

  15. High temperature two component explosive

    DOEpatents

    Mars, James E.; Poole, Donald R.; Schmidt, Eckart W.; Wang, Charles

    1981-01-01

    A two component, high temperature, thermally stable explosive composition comprises a liquid or low melting oxidizer and a liquid or low melting organic fuel. The oxidizer and fuel in admixture are incapable of substantial spontaneous exothermic reaction at temperatures on the order of 475.degree. K. At temperatures on the order of 475.degree. K., the oxidizer and fuel in admixture have an activation energy of at least about 40 kcal/mol. As a result of the high activation energy, the preferred explosive compositions are nondetonable as solids at ambient temperature, and become detonable only when heated beyond the melting point. Preferable oxidizers are selected from alkali or alkaline earth metal nitrates, nitrites, perchlorates, and/or mixtures thereof. Preferred fuels are organic compounds having polar hydrophilic groups. The most preferred fuels are guanidinium nitrate, acetamide and mixtures of the two. Most preferred oxidizers are eutectic mixtures of lithium nitrate, potassium nitrate and sodium nitrate, of sodium nitrite, sodium nitrate and potassium nitrate, and of potassium nitrate, calcium nitrate and sodium nitrate.

  16. High temperature structural sandwich panels

    NASA Astrophysics Data System (ADS)

    Papakonstantinou, Christos G.

    High strength composites are being used for making lightweight structural panels that are being employed in aerospace, naval and automotive structures. Recently, there is renewed interest in use of these panels. The major problem of most commercial available sandwich panels is the fire resistance. A recently developed inorganic matrix is investigated for use in cases where fire and high temperature resistance are necessary. The focus of this dissertation is the development of a fireproof composite structural system. Sandwich panels made with polysialate matrices have an excellent potential for use in applications where exposure to high temperatures or fire is a concern. Commercial available sandwich panels will soften and lose nearly all of their compressive strength temperatures lower than 400°C. This dissertation consists of the state of the art, the experimental investigation and the analytical modeling. The state of the art covers the performance of existing high temperature composites, sandwich panels and reinforced concrete beams strengthened with Fiber Reinforced Polymers (FRP). The experimental part consists of four major components: (i) Development of a fireproof syntactic foam with maximum specific strength, (ii) Development of a lightweight syntactic foam based on polystyrene spheres, (iii) Development of the composite system for the skins. The variables are the skin thickness, modulus of elasticity of skin and high temperature resistance, and (iv) Experimental evaluation of the flexural behavior of sandwich panels. Analytical modeling consists of a model for the flexural behavior of lightweight sandwich panels, and a model for deflection calculations of reinforced concrete beams strengthened with FRP subjected to fatigue loading. The experimental and analytical results show that sandwich panels made with polysialate matrices and ceramic spheres do not lose their load bearing capability during severe fire exposure, where temperatures reach several

  17. Motor for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Roopnarine (Inventor)

    2013-01-01

    A high temperature motor has a stator with poles formed by wire windings, and a rotor with magnetic poles on a rotor shaft positioned coaxially within the stator. The stator and rotor are built up from stacks of magnetic-alloy laminations. The stator windings are made of high temperature magnet wire insulated with a vitreous enamel film, and the wire windings are bonded together with ceramic binder. A thin-walled cylinder is positioned coaxially between the rotor and the stator to prevent debris from the stator windings from reaching the rotor. The stator windings are wound on wire spools made of ceramic, thereby avoiding need for mica insulation and epoxy/adhesive. The stator and rotor are encased in a stator housing with rear and front end caps, and rear and front bearings for the rotor shaft are mounted on external sides of the end caps to keep debris from the motor migrating into the bearings' races.

  18. High Temperature Heat Exchanger Project

    SciTech Connect

    Anthony E. Hechanova, Ph.D.

    2008-09-30

    The UNLV Research Foundation assembled a research consortium for high temperature heat exchanger design and materials compatibility and performance comprised of university and private industry partners under the auspices of the US DOE-NE Nuclear Hydrogen Initiative in October 2003. The objectives of the consortium were to conduct investigations of candidate materials for high temperature heat exchanger componets in hydrogen production processes and design and perform prototypical testing of heat exchangers. The initial research of the consortium focused on the intermediate heat exchanger (located between the nuclear reactor and hydrogen production plan) and the components for the hydrogen iodine decomposition process and sulfuric acid decomposition process. These heat exchanger components were deemed the most challenging from a materials performance and compatibility perspective

  19. High pressure and high temperature apparatus

    DOEpatents

    Voronov, Oleg A.

    2005-09-13

    A design for high pressure/high temperature apparatus and reaction cell to achieve .about.30 GPa pressure in .about.1 cm volume and .about.100 GPa pressure in .about.1 mm volumes and 20-5000.degree. C. temperatures in a static regime. The device includes profiled anvils (28) action on a reaction cell (14, 16) containing the material (26) to be processed. The reaction cell includes a heater (18) surrounded by insulating layers and screens. Surrounding the anvils are cylindrical inserts and supporting rings (30-48) whose hardness increases towards the reaction cell. These volumes may be increased considerably if applications require it, making use of presses that have larger loading force capability, larger frames and using larger anvils.

  20. High temperature solar thermal receiver

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A design concept for a high temperature solar thermal receiver to operate at 3 atmospheres pressure and 2500 F outlet was developed. The performance and complexity of windowed matrix, tube-header, and extended surface receivers were evaluated. The windowed matrix receiver proved to offer substantial cost and performance benefits. An efficient and cost effective hardware design was evaluated for a receiver which can be readily interfaced to fuel and chemical processes or to heat engines for power generation.

  1. HIGH TEMPERATURE MICROSCOPE AND FURNACE

    DOEpatents

    Olson, D.M.

    1961-01-31

    A high-temperature microscope is offered. It has a reflecting optic situated above a molten specimen in a furnace and reflecting the image of the same downward through an inert optic member in the floor of the furnace, a plurality of spaced reflecting plane mirrors defining a reflecting path around the furnace, a standard microscope supported in the path of and forming the end terminus of the light path.

  2. High temperature turbine engine structure

    DOEpatents

    Carruthers, William D.; Boyd, Gary L.

    1993-01-01

    A high temperature ceramic/metallic turbine engine includes a metallic housing which journals a rotor member of the turbine engine. A ceramic disk-like shroud portion of the engine is supported on the metallic housing portion and maintains a close running clearance with the rotor member. A ceramic spacer assembly maintains the close running clearance of the shroud portion and rotor member despite differential thermal movements between the shroud portion and metallic housing portion.

  3. High temperature turbine engine structure

    DOEpatents

    Carruthers, William D.; Boyd, Gary L.

    1994-01-01

    A high temperature ceramic/metallic turbine engine includes a metallic housing which journals a rotor member of the turbine engine. A ceramic disk-like shroud portion of the engine is supported on the metallic housing portion and maintains a close running clearance with the rotor member. A ceramic spacer assembly maintains the close running clearance of the shroud portion and rotor member despite differential thermal movements between the shroud portion and metallic housing portion.

  4. High temperature turbine engine structure

    DOEpatents

    Carruthers, William D.; Boyd, Gary L.

    1992-01-01

    A high temperature ceramic/metallic turbine engine includes a metallic housing which journals a rotor member of the turbine engine. A ceramic disk-like shroud portion of the engine is supported on the metallic housing portion and maintains a close running clearance with the rotor member. A ceramic spacer assembly maintains the close running clearance of the shroud portion and rotor member despite differential thermal movements between the shroud portion and metallic housing portion.

  5. High-temperature geothermal cableheads

    SciTech Connect

    Coquat, J.A.; Eifert, R.W.

    1981-11-01

    Two high-temperature, corrosion-resistant logging cableheads which use metal seals and a stable fluid to achieve proper electrical terminations and cable-sonde interfacings are described. A tensile bar provides a calibrated yield point, and a cone assembly anchors the cable armor to the head. Electrical problems of the sort generally ascribable to the cable-sonde interface were absent during demonstration hostile-environment loggings in which these cableheads were used.

  6. High temperature catalytic membrane reactors

    SciTech Connect

    Not Available

    1990-03-01

    Current state-of-the-art inorganic oxide membranes offer the potential of being modified to yield catalytic properties. The resulting modules may be configured to simultaneously induce catalytic reactions with product concentration and separation in a single processing step. Processes utilizing such catalytically active membrane reactors have the potential for dramatically increasing yield reactions which are currently limited by either thermodynamic equilibria, product inhibition, or kinetic selectivity. Examples of commercial interest include hydrogenation, dehydrogenation, partial and selective oxidation, hydrations, hydrocarbon cracking, olefin metathesis, hydroformylation, and olefin polymerization. A large portion of the most significant reactions fall into the category of high temperature, gas phase chemical and petrochemical processes. Microporous oxide membranes are well suited for these applications. A program is proposed to investigate selected model reactions of commercial interest (i.e. dehydrogenation of ethylbenzene to styrene and dehydrogenation of butane to butadiene) using a high temperature catalytic membrane reactor. Membranes will be developed, reaction dynamics characterized, and production processes developed, culminating in laboratory-scale demonstration of technical and economic feasibility. As a result, the anticipated increased yield per reactor pass economic incentives are envisioned. First, a large decrease in the temperature required to obtain high yield should be possible because of the reduced driving force requirement. Significantly higher conversion per pass implies a reduced recycle ratio, as well as reduced reactor size. Both factors result in reduced capital costs, as well as savings in cost of reactants and energy.

  7. High temperature polymer matrix composites

    NASA Technical Reports Server (NTRS)

    Meador, Michael A.

    1987-01-01

    With the increased emphasis on high performance aircraft the need for lightweight, thermal/oxidatively stable materials is growing. Because of their ease of fabrication, high specific strength, and ability to be tailored chemically to produce a variety of mechanical and physical properties, polymers and polymer matrix composites present themselves as attractive materials for a number of aeropropulsion applications. In the early 1970s researchers at the NASA Lewis Research Center developed a highly processable, thermally stable (600 F) polyimide, PMR-15. Since that time, PMR-15 has become commercially available and has found use in military aircraft, in particular, the F-404 engine for the Navy's F/A-18 strike fighter. The NASA Lewis'contributions to high temperature polymer matrix composite research will be discussed as well as current and future directions.

  8. High temperature jet fuel stabilizers

    SciTech Connect

    Yoon, E.M.; Selvaraj, L.; Stallman, J.B.

    1996-10-01

    We have previously discussed the rationale for development of jet fuels with enhanced thermal stability at temperatures above 400{degrees}C. At these temperatures we are encroaching into the so-called pyrolysis regime, where the cleavage of carbon-carbon bonds into free radicals is facile and leads to the rapid degradation of aliphatic hydrocarbons. Notwithstanding, we established that the formation of carbonaceous materials is significantly retarded in hydrocarbon mixtures containing molecules such as benzyl alcohol (BzOH). It was ascertained that BzOH acts as a hydrogen donor capping aliphatic radicals formed at temperatures > 400{degrees}C while transforming into relatively stable products. These results suggested is superior high temperature thermal stabilizers might be found among the more conventional hydrogen donors that find application in coal liquefaction and similar hydrogenation processes. Here we present the results of {open_quotes}screening{close_quotes} and kinetic studies of traditional hydrogen donors, such as tetralin, tetrahydroquinoline and the like, together with simple derivatives designed to test the importance of specific factors in the thermal stabilization of jet fuels.

  9. The temperature and ionization structure of the emitting gas in HII galaxies: implications for the accuracy of abundance determinations

    NASA Astrophysics Data System (ADS)

    Hägele, Guillermo F.; Pérez-Montero, Enrique; Díaz, Ángeles I.; Terlevich, Elena; Terlevich, Roberto

    2006-10-01

    observed objects from the O+/O2+ and S+/S2+ ratios points to high values of the ionizing radiation, as traced by the values of the `softness parameter' η which is less than 1 for the three objects. The use of line temperatures derived from T([OIII]) based on current photoionization models yields for the two highest excitation objects, much higher values of η which would imply lower ionizing temperatures. This is, however, inconsistent with the ionization structure as probed by the measured emission-line intensities. Finally, we have measured the T(Bac) for the three observed objects and derived temperature fluctuations. Only for one of the objects, the temperature fluctuation is significant and could lead to higher oxygen abundances by about 0.20dex.

  10. High temperature PEM fuel cells

    NASA Astrophysics Data System (ADS)

    Zhang, Jianlu; Xie, Zhong; Zhang, Jiujun; Tang, Yanghua; Song, Chaojie; Navessin, Titichai; Shi, Zhiqing; Song, Datong; Wang, Haijiang; Wilkinson, David P.; Liu, Zhong-Sheng; Holdcroft, Steven

    There are several compelling technological and commercial reasons for operating H 2/air PEM fuel cells at temperatures above 100 °C. Rates of electrochemical kinetics are enhanced, water management and cooling is simplified, useful waste heat can be recovered, and lower quality reformed hydrogen may be used as the fuel. This review paper provides a concise review of high temperature PEM fuel cells (HT-PEMFCs) from the perspective of HT-specific materials, designs, and testing/diagnostics. The review describes the motivation for HT-PEMFC development, the technology gaps, and recent advances. HT-membrane development accounts for ∼90% of the published research in the field of HT-PEMFCs. Despite this, the status of membrane development for high temperature/low humidity operation is less than satisfactory. A weakness in the development of HT-PEMFC technology is the deficiency in HT-specific fuel cell architectures, test station designs, and testing protocols, and an understanding of the underlying fundamental principles behind these areas. The development of HT-specific PEMFC designs is of key importance that may help mitigate issues of membrane dehydration and MEA degradation.

  11. Compensated High Temperature Strain Gage

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A device for measuring strain in substrates at high temperatures in which the thermally induced apparent strain is nulled is described. Two gages are used, one active gage and one compensating gage. Both gages are placed on the substrate to be gaged; the active gage is attached such that it responds to mechanical and thermally induced apparent strain while the compensating gage is attached such that it does not respond to mechanical strain and and measures only thermally induced apparent strain. A thermal blanket is placed over the two gages to maintain the gages at the same temperature. The two gages are wired as adjacent arms of a wheatstone bridge which nulls the thermally induced apparent strain giving a true reading of the mechanical strain in the substrate.

  12. Ultra-High Temperature Ceramics

    NASA Technical Reports Server (NTRS)

    Rasky, Dan; Bull, Jeff

    1994-01-01

    Recent developments in ultra-high temperature ceramic composites, and their application to advanced vehicle thermal protection systems will be discussed. Research and testing of refractory ceramics has resulted in the identification of a new family of ceramic composites that promise temperature performance to 4000 F+, significantly beyond the current state-of-the-art of reusable systems which are limited to approximately 300 F. This new family of materials includes zirconium and hafnium diboride composites with various reinforcements, such as fibers and particulates. Preliminary material characterization and testing results, including plasma arc-jet testing of prototype vehicle components, will be described. Future directions for the research and material development activities will also be discussed.

  13. A Rainfall- and Temperature-Driven Abundance Model for Aedes albopictus Populations

    PubMed Central

    Tran, Annelise; L’Ambert, Grégory; Lacour, Guillaume; Benoît, Romain; Demarchi, Marie; Cros, Myriam; Cailly, Priscilla; Aubry-Kientz, Mélaine; Balenghien, Thomas; Ezanno, Pauline

    2013-01-01

    The mosquito Aedes (Stegomyia) albopictus (Skuse) (Diptera: Culicidae) is an invasive species which has colonized Southern Europe in the last two decades. As it is a competent vector for several arboviruses, its spread is of increasing public health concern, and there is a need for appropriate monitoring tools. In this paper, we have developed a modelling approach to predict mosquito abundance over time, and identify the main determinants of mosquito population dynamics. The model is temperature- and rainfall-driven, takes into account egg diapause during unfavourable periods, and was used to model the population dynamics of Ae. albopictus in the French Riviera since 2008. Entomological collections of egg stage from six locations in Nice conurbation were used for model validation. We performed a sensitivity analysis to identify the key parameters of the mosquito population dynamics. Results showed that the model correctly predicted entomological field data (Pearson r correlation coefficient values range from 0.73 to 0.93). The model’s main control points were related to adult’s mortality rates, the carrying capacity in pupae of the environment, and the beginning of the unfavourable period. The proposed model can be efficiently used as a tool to predict Ae. albopictus population dynamics, and to assess the efficiency of different control strategies. PMID:23624579

  14. High temperature sealed electrochemical cell

    SciTech Connect

    Valentin Chung, Brice Hoani; Burke, Paul J.; Sadoway, Donald R.

    2015-10-06

    A cell for high temperature electrochemical reactions is provided. The cell includes a container, at least a portion of the container acting as a first electrode. An extension tube has a first end and a second end, the extension tube coupled to the container at the second end forming a conduit from the container to said first end. A second electrode is positioned in the container and extends out of the container via the conduit. A seal is positioned proximate the first end of the extension tube, for sealing the cell.

  15. Passivation of high temperature superconductors

    NASA Technical Reports Server (NTRS)

    Vasquez, Richard P. (Inventor)

    1991-01-01

    The surface of high temperature superconductors such as YBa2Cu3O(7-x) are passivated by reacting the native Y, Ba and Cu metal ions with an anion such as sulfate or oxalate to form a surface film that is impervious to water and has a solubility in water of no more than 10(exp -3) M. The passivating treatment is preferably conducted by immersing the surface in dilute aqueous acid solution since more soluble species dissolve into the solution. The treatment does not degrade the superconducting properties of the bulk material.

  16. High temperature insulation barrier composite

    NASA Technical Reports Server (NTRS)

    Onstott, Joseph W. (Inventor)

    1989-01-01

    A composite material suitable for providing insulation for the nozzle structure of the Space Shuttle and other similar surfaces is disclosed. The composite layer is comprised of an outer skin layer of nickel chromium and an interleaved inner region comprising a top layer of nickel chromium foil which acts as a primary convective shield. There are at least two layers of alumina batting adjacent to the layers of silicon carbide fabric. An additional layer of nickel chromium foil is used as a secondary convective shield. The composite is particularly advantageous for use as nozzle insulation because of its ability to withstand high reentry temperatures, its flexibility, oxidation resistance, low conductivity, and light weight.

  17. Advanced high-temperature batteries

    NASA Technical Reports Server (NTRS)

    Nelson, Paul A.

    1989-01-01

    The promise of very high specific energy and power was not yet achieved for practical battery systems. Some recent approaches are discussed for new approaches to achieving high performance for lithium/DeS2 cells and sodium/metal chloride cells. The main problems for the development of successful LiAl/FeS2 cells were the instability of the FeS2 electrode, which has resulted in rapidly declining capacity, the lack of an internal mechanism for accommodating overcharge of a cell, thus requiring the use of external charge control on each individual cell, and the lack of a suitable current collector for the positive electrode other than expensive molybdenum sheet material. Much progress was made in solving the first two problems. Reduction of the operating temperatures to 400 C by a change in electrolyte composition has increased the expected life to 1000 cycles. Also, a lithium shuttle mechanism was demonstrated for selected electrode compositions that permits sufficient overcharge tolerance to adjust for the normally expected cell-to-cell deviation in coulombic efficiency. Sodium/sulfur batteries and sodium/metal chloride batteries have demonstrated good reliability and long cycle life. For applications where very high power is desired, new electrolyte coinfigurations would be required. Design work was carried out for the sodium/metal chloride battery that demonstrates the feasibility of achieving high specific energy and high power for large battery cells having thin-walled high-surface area electrolytes.

  18. On the Origin of the High Lithium Abundance in the Halo Star BD+23{\\ }3912

    NASA Astrophysics Data System (ADS)

    Deliyannis, C. P.; King, J. R.; Boesgaard, A. M.

    1996-09-01

    The Li abundance of the halo star BD+23{\\ }3912 ([Fe/H]=-1.5) lies a factor of 2-3 above the Spite plateau. This remarkable difference could reflect either less-than-average stellar Li depletion from a higher primordial Li abundance (as predicted by the Yale rotational stellar evolutionary models), which may have interesting implications for Big Bang nucleosynthesis, or the extraordinary action of Galactic Li production mechanisms (or both). We use our high resolution, high S/N Keck HIRES spectrum of BD+23{\\ }3912 to determine the s-process element abundances and (6) Li/(7) Li ratio in this star. These values serve as signatures for two possible Li production scenarios: {\\ }the (7) Be transport mechanism in AGB stars, and cosmic ray interactions with the ISM. The unremarkable abundances of Y, Zr, Ba, La, Nd, and Sm that we derive argue against a significant contribution to this star's excess Li from AGB production mechanisms carrying an s-process signature. Our conservative upper limit of (6) Li/(7) Li{<=}0.15 (compared to 0.25-0.50 expected from cosmic ray production) argues against cosmic ray + ISM interactions as the source for the excess Li, unless Li depletion from an even higher abundance has occurred with preferential (6) Li depletion. Highly speculative RGB production scenarios also seem unlikely given the normal Na and Al abundances we find and the normal C and O abundances determined by others. While the high Li abundance in BD+23{\\ }3912 is consistent with that expected from Yale rotational models having a lower-than-average initial angular momentum, future observations of ν-process elements (particularly (11) B) produced in supernovae should provide additional constraints on any enrichment scenarios seeking to explain the large Li abundance of this interesting star.

  19. Temperature and abundances in the Jovian auroral stratosphere. 1: Ethane as a probe of the millibar region

    NASA Technical Reports Server (NTRS)

    Livengood, Timothy A.; Kostiuk, Theodor; Espenak, Fred

    1993-01-01

    We report infrared heterodyne spectroscopy (lambda/delta lambda is approximately 10(exp 6)) of C2H6 emission at 11.9 microns from the northern Jovian auroral region, in observations conducted over December 2-7, 1989. Accurately measured line shapes provide information on C2H6 abundance as well as temperature and permit retrieval of the source pressure region. Enhanced emission was observed in the longitude range approximately 150-180 deg at approximately 60 deg north latitude, approximately corresponding to the CH4 7.8 micron hot spot and the region of brightest UV aurora. Significant brightness variations were observed in the hot spot emissions on a time scale of approximately 20 hours. Analysis of the brightest hot spot spectra indicates C2H6 mole fractions of approximately (6.3-6.8) x 10(exp -6) at temperatures of approximately 182-184 K at 1 mbar, compared to mole fractions of (3.8 +/- 1.4) x 10(exp -6) averaged over spectra outside the hot spot at a temperature of approximately 172 K at the same pressure. Fixing the mole fraction to the lower limit retrieved in the quiescent (non-hot spot) region allows the temperature at 1 mbar to be as high as approximately 200 K within the hot spot. These results provide upper limits to the temperature increase near the source of the C2H6 thermal infrared emission. Combined with results from similar measurements of ethylene emission probing the approximately 10-microbar region (Kostiuk et al., this issue), altitude information on the thermal structure of the Jovian auroral stratosphere can be obtained for the first time.

  20. High modulus high temperature glass fibers

    NASA Technical Reports Server (NTRS)

    Bacon, J. F.

    1973-01-01

    The search for a new high-modulus, high-temperature glass fiber involved the preparation of 500 glass compositions lying in 12 glass fields. These systems consisted primarily of low atomic number oxides and rare-earth oxides. Direct optical measurements of the kinetics of crystallization of the cordierite-rare earth system, for example, showed that the addition of rare-earth oxides decreased the rate of formation of cordierite crystals. Glass samples prepared from these systems proved that the rare-earth oxides made large specific contributions to the Young's modulus of the glasses. The best glasses have moduli greater than 21 million psi, the best glass fibers have moduli greater than 18 million psi, and the best glass fiber-epoxy resin composites have tensile strengths of 298,000 psi, compressive strengths of at least 220,000 psi, flexural strengths of 290,000 psi, and short-beam shear strengths of almost 17,000 psi.

  1. Seasonal temperature and precipitation regulate brook trout young-of-the-year abundance and population dynamics

    USGS Publications Warehouse

    Kanno, Yoichiro; Pregler, Kasey C.; Hitt, Nathaniel P.; Letcher, Benjamin H.; Hocking, Daniel; Wofford, John E.B.

    2015-01-01

    Our results indicate that YOY abundance is a key driver of brook trout population dynamics that is mediated by seasonal weather patterns. A reliable assessment of climate change impacts on brook trout needs to account for how alternations in seasonal weather patterns impact YOY abundance and how such relationships may differ across the range of brook trout distribution.

  2. Relations between fish abundances, summer temperatures, and forest harvest in a northern Minnesota stream system from 1997 to 2007

    USGS Publications Warehouse

    Merten, Eric C.; Hemstad, Nathaniel A.; Eggert, S.L.; Johnson, L.B.; Kolka, Randall K.; Newman, Raymond M.; Vondracek, Bruce C.

    2010-01-01

    Short-term effects of forest harvest on fish habitat have been well documented, including sediment inputs, leaf litter reductions, and stream warming. However, few studies have considered changes in local climate when examining postlogging changes in fish communities. To address this need, we examined fish abundances between 1997 and 2007 in a basin in a northern hardwood forest. Streams in the basin were subjected to experimental riparian forest harvest in fall 1997. We noted a significant decrease for fish index of biotic integrity and abundance of Salvelinus fontinalis and Phoxinus eos over the study period. However, for P. eos and Culaea inconstans, the temporal patterns in abundances were related more to summer air temperatures than to fine sediment or spring precipitation when examined using multiple regressions. Univariate regressions suggested that summer air temperatures influenced temporal patterns in fish communities more than fine sediment or spring precipitation.

  3. Relations between fish abundances, summer temperatures, and forest harvest in a northern Minnesota stream system from 1997 to 2007

    USGS Publications Warehouse

    Merten, Eric C.; Hemstad, Nathaniel A.; Eggert, L.S.; Johnson, L.B.; Kolka, R.K.; Newman, Raymond M.; Vondracek, Bruce C.

    2015-01-01

    Short-term effects of forest harvest on fish habitat have been well documented, including sediment inputs, leaf litter reductions, and stream warming. However, few studies have considered changes in local climate when examining postlogging changes in fish communities. To address this need, we examined fish abundances between 1997 and 2007 in a basin in a northern hardwood forest. Streams in the basin were subjected to experimental riparian forest harvest in fall 1997. We noted a significant decrease for fish index of biotic integrity and abundance of Salvelinus fontinalis and Phoxinus eos over the study period. However, for P. eos and Culaea inconstans, the temporal patterns in abundances were related more to summer air temperatures than to fine sediment or spring precipitation when examined using multiple regressions. Univariate regressions suggested that summer air temperatures influenced temporal patterns in fish communities more than fine sediment or spring precipitation.

  4. Topological susceptibility at high temperature on the lattice

    NASA Astrophysics Data System (ADS)

    Frison, J.; Kitano, R.; Matsufuru, H.; Mori, S.; Yamada, N.

    2016-09-01

    QCD topological susceptibility at high temperature, χ t ( T ), provides an important input for the estimate of the axion abundance in the present Universe. While the model independent determination of χ t ( T ) should be possible from the first principles using lattice QCD, existing methods fail at high temperature, since not only the probability that non-trivial topological sectors appear in the configuration generation process but also the local topological fluctuations get strongly suppressed. We propose a novel method to calculate the temperature dependence of topological susceptibility at high temperature. A feasibility test is performed on a small lattice in the quenched approximation, and the results are compared with the prediction of the dilute instanton gas approximation. It is found that the method works well especially at very high temperature and the result is consistent with the instanton calculus down to T ˜ 2 T c within the statistical uncertainty.

  5. Effects of biochar and elevated soil temperature on soil microbial activity and abundance in an agricultural system

    NASA Astrophysics Data System (ADS)

    Bamminger, Chris; Poll, Christian; Marhan, Sven

    2014-05-01

    As a consequence of Global Warming, rising surface temperatures will likely cause increased soil temperatures. Soil warming has already been shown to, at least temporarily, increase microbial activity and, therefore, the emissions of greenhouse gases like CO2 and N2O. This underlines the need for methods to stabilize soil organic matter and to prevent further boost of the greenhouse gas effect. Plant-derived biochar as a soil amendment could be a valuable tool to capture CO2 from the atmosphere and sequestrate it in soil on the long-term. During the process of pyrolysis, plant biomass is heated in an oxygen-low atmosphere producing the highly stable solid matter biochar. Biochar is generally stable against microbial degradation due to its chemical structure and it, therefore, persists in soil for long periods. Previous experiments indicated that biochar improves or changes several physical or chemical soil traits such as water holding capacity, cation exchange capacity or soil structure, but also biotic properties like microbial activity/abundance, greenhouse gas emissions and plant growth. Changes in the soil microbial abundance and community composition alter their metabolism, but likely also affect plant productivity. The interaction of biochar addition and soil temperature increase on soil microbial properties and plant growth was yet not investigated on the field scale. To investigate whether warming could change biochar effects in soil, we conducted a field experiment attached to a soil warming experiment on an agricultural experimental site near the University of Hohenheim, already running since July 2008. The biochar field experiment was set up as two-factorial randomized block design (n=4) with the factors biochar amendment (0, 30 t ha-1) and soil temperature (ambient, elevated=ambient +2.5° C) starting from August 2013. Each plot has a dimension of 1x1m and is equipped with combined soil temperature and moisture sensors. Slow pyrolysis biochar from the C

  6. VizieR Online Data Catalog: High-precision abundances for stars with planets (Ramirez+, 2014)

    NASA Astrophysics Data System (ADS)

    Ramirez, I.; Melendez, J.; Asplund, M.

    2013-11-01

    High-precision stellar parameters and chemical abundances are presented for 111 stars; 52 of them are late-F type dwarfs and 59 are metal-rich solar analogs. The atomic linelist employed in the derivation of chemical abundances is also given. This linelist includes hyperfine structure parameters for some species. The stars' isochrone masses and ages are also reported, along with estimates of chromospheric activity. (5 data files).

  7. Multifunctional, High-Temperature Nanocomposites

    NASA Technical Reports Server (NTRS)

    Connell, John W.; Smith, Joseph G.; Siochi, Emilie J.; Working, Dennis C.; Criss, Jim M.; Watson, Kent A.; Delozier, Donavon M.; Ghose, Sayata

    2007-01-01

    In experiments conducted as part of a continuing effort to incorporate multifunctionality into advanced composite materials, blends of multi-walled carbon nanotubes and a resin denoted gPETI-330 h (wherein gPETI h is an abbreviation for gphenylethynyl-terminated imide h) were prepared, characterized, and fabricated into moldings. PETI-330 was selected as the matrix resin in these experiments because of its low melt viscosity (<10 poise at a temperature of 280 C), excellent melt stability (lifetime >2 hours at 280 C), and high temperature performance (>1,000 hours at 288 C). The multi-walled carbon nanotubes (MWCNTs), obtained from the University of Kentucky, were selected because of their electrical and thermal conductivity and their small diameters. The purpose of these experiments was to determine the combination of thermal, electrical, and mechanical properties achievable while still maintaining melt processability. The PETI-330/MWCNT mixtures were prepared at concentrations ranging from 3 to 25 weight-percent of MWCNTs by dry mixing of the constituents in a ball mill using zirconia beads. The resulting powders were characterized for degree of mixing and thermal and rheological properties. The neat resin was found to have melt viscosity between 5 and 10 poise. At 280 C and a fixed strain rate, the viscosity was found to increase with time. At this temperature, the phenylethynyl groups do not readily react and so no significant curing of the resin occurred. For MWCNT-filled samples, melt viscosity was reasonably steady at 280 C and was greater in samples containing greater proportions of MWCNTs. The melt viscosity for 20 weightpercent of MWCNTs was found to be .28,000 poise, which is lower than the initial estimated allowable maximum value of 60,000 poise for injection molding. Hence, MWCNT loadings of as much as 20 percent were deemed to be suitable compositions for scale-up. High-resolution scanning electron microscopy (HRSEM) showed the MWCNTs to be well

  8. Sialons as high temperature insulators

    NASA Technical Reports Server (NTRS)

    Phillips, W. M.; Kuo, Y. S.

    1978-01-01

    Sialons were evaluated for application as high temperature electrical insulators in contact with molybdenum and tungsten components in hard vacuum applications. Both D.C. and variable frequency A.C. resistivity data indicate the sialons to have electrical resistivity similar to common oxide in the 1000 C or higher range. Metallographic evaluations indicate good bonding of the type 15R ALN polytype to molybdenum and tungsten. The beta prime or modified silicon nitride phase was unacceptable in terms of vacuum stability. Additives effect on electrical resistivity. Similar resistivity decreases were produced by additions of molybdenum or tungsten to form cermets. The use of hot pressing at 1800 C with ALN, Al2 O3 and Si3N4 starting powders produced a better product than did a combination of SiO2 and AIN staring powders. It was indicated that sialons will be suitable insulators in the 1600K range in contact with molybdenum or tungsten if they are produced as a pure ceramic and subsequently bonded to the metal components at temperatures in the 1600K range.

  9. High abundances of aerobic anoxygenic photosynthetic bacteria in the South Pacific Ocean.

    PubMed

    Lami, Raphaël; Cottrell, Matthew T; Ras, Joséphine; Ulloa, Osvaldo; Obernosterer, Ingrid; Claustre, Hervé; Kirchman, David L; Lebaron, Philippe

    2007-07-01

    Little is known about the abundance, distribution, and ecology of aerobic anoxygenic phototrophic (AAP) bacteria, particularly in oligotrophic environments, which represent 60% of the ocean. We investigated the abundance of AAP bacteria across the South Pacific Ocean, including the center of the gyre, the most oligotrophic water body of the world ocean. AAP bacteria, Prochlorococcus, and total prokaryotic abundances, as well as bacteriochlorophyll a (BChl a) and divinyl-chlorophyll a concentrations, were measured at several depths in the photic zone along a gradient of oligotrophic conditions. The abundances of AAP bacteria and Prochlorococcus were high, together accounting for up to 58% of the total prokaryotic community. The abundance of AAP bacteria alone was up to 1.94 x 10(5) cells ml(-1) and as high as 24% of the overall community. These measurements were consistent with the high BChl a concentrations (up to 3.32 x 10(-3) microg liter(-1)) found at all stations. However, the BChl a content per AAP bacterial cell was low, suggesting that AAP bacteria are mostly heterotrophic organisms. Interestingly, the biovolume and therefore biomass of AAP bacteria was on average twofold higher than that of other prokaryotic cells. This study demonstrates that AAP bacteria can be abundant in various oligotrophic conditions, including the most oligotrophic regime of the world ocean, and can account for a large part of the bacterioplanktonic carbon stock.

  10. Faraday imaging at high temperatures

    DOEpatents

    Hackel, Lloyd A.; Reichert, Patrick

    1997-01-01

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid.

  11. Faraday imaging at high temperatures

    DOEpatents

    Hackel, L.A.; Reichert, P.

    1997-03-18

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid. 3 figs.

  12. High Temperature Particle Filtration Technology

    SciTech Connect

    Besmann, T.M.

    2001-11-13

    High temperature filtration can serve to improve the economic, environmental, and energy performance of chemical processes. This project was designed to evaluate the stability of filtration materials in the environments of the production of dimethyldichlorosilane (DDS). In cooperation with Dow Corning, chemical environments for the fluidized bed reactor where silicon is converted to DDS and the incinerator where vents are cornbusted were characterized. At Oak Ridge National Laboratory (ORNL) an exposure system was developed that could simulate these two environments. Filter samples obtained from third parties were exposed to the environments for periods up to 1000 hours. Mechanical properties before and after exposure were determined by burst-testing rings of filter material. The results indicated that several types of filter materials would likely perform well in the fluid bed environment, and two materials would be good candidates for the incinerator environment.

  13. High Temperature Capacitive Strain Gage

    NASA Technical Reports Server (NTRS)

    Wnuk, Stephen P., Jr.; Wnuk, Stephen P., III; Wnuk, V. P.

    1990-01-01

    Capacitive strain gages designed for measurements in wind tunnels to 2000 F were built and evaluated. Two design approaches were followed. One approach was based on fixed capacitor plates with a movable ground plane inserted between the plates to effect differential capacitive output with strain. The second approach was based on movable capacitor plates suspended between sapphire bearings, housed in a rugged body, and arranged to operate as a differential capacitor. A sapphire bearing gage (1/4 in. diameter x 1 in. in size) was built with a range of 50,000 and a resolution of 200 microstrain. Apparent strain on Rene' 41 was less than + or - 1000 microstrain from room temperature to 2000 F. Three gage models were built from the Ground Plane Differential concept. The first was 1/4 in. square by 1/32 in. high and useable to 700 F. The second was 1/2 in. square by 1/16 in. high and useable to 1440 F. The third, also 1/2 in. square by 1/16 in. high was expected to operate in the 1600 to 2000 F range, but was not tested because time and funding ended.

  14. High temperature control rod assembly

    DOEpatents

    Vollman, Russell E.

    1991-01-01

    A high temperature nuclear control rod assembly comprises a plurality of substantially cylindrical segments flexibly joined together in succession by ball joints. The segments are made of a high temperature graphite or carbon-carbon composite. The segment includes a hollow cylindrical sleeve which has an opening for receiving neutron-absorbing material in the form of pellets or compacted rings. The sleeve has a threaded sleeve bore and outer threaded surface. A cylindrical support post has a threaded shaft at one end which is threadably engaged with the sleeve bore to rigidly couple the support post to the sleeve. The other end of the post is formed with a ball portion. A hollow cylindrical collar has an inner threaded surface engageable with the outer threaded surface of the sleeve to rigidly couple the collar to the sleeve. the collar also has a socket portion which cooperates with the ball portion to flexibly connect segments together to form a ball and socket-type joint. In another embodiment, the segment comprises a support member which has a threaded shaft portion and a ball surface portion. The threaded shaft portion is engageable with an inner threaded surface of a ring for rigidly coupling the support member to the ring. The ring in turn has an outer surface at one end which is threadably engageably with a hollow cylindrical sleeve. The other end of the sleeve is formed with a socket portion for engagement with a ball portion of the support member. In yet another embodiment, a secondary rod is slidably inserted in a hollow channel through the center of the segment to provide additional strength. A method for controlling a nuclear reactor utilizing the control rod assembly is also included.

  15. Abundances of Local Group Globular Clusters Using High Resolution Integrated Light Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sakari, Charli; McWilliam, A.; Venn, K.; Shetrone, M. D.; Dotter, A. L.; Mackey, D.

    2014-01-01

    Abundances and kinematics of extragalactic globular clusters provide valuable clues about galaxy and globular cluster formation in a wide variety of environments. In order to obtain such information about distant, unresolved systems, specific observational techniques are required. An Integrated Light Spectrum (ILS) provides a single spectrum from an entire stellar population, and can therefore be used to determine integrated cluster abundances. This dissertation investigates the accuracy of high resolution ILS analysis methods, using ILS (taken with the Hobby-Eberly Telescope) of globular clusters associated with the Milky Way (47 Tuc, M3, M13, NGC 7006, and M15) and then applies the method to globular clusters in the outer halo of M31 (from the Pan-Andromeda Archaeological Survey, or PAndAS). Results show that: a) as expected, the high resolution method reproduces individual stellar abundances for elements that do not vary within a cluster; b) the presence of multiple populations does affect the abundances of elements that vary within the cluster; c) certain abundance ratios are very sensitive to systematic effects, while others are not; and d) certain abundance ratios (e.g. [Ca/Fe]) can be accurately obtained from unresolved systems. Applications of ILABUNDS to the PAndAS clusters reveal that accretion may have played an important role in the formation of M31's outer halo.

  16. High Pressure Study on High Temperature Superconductors

    NASA Astrophysics Data System (ADS)

    Lin, Jauyn Grace

    In spite of the progress on the understanding of high-temperature superconductivity (HTS), there is still not sufficient evidence to differentiate one theoretical model from the others. In an attempt to relate the crystal structures of high-temperature superconductors (HTS's) to the mechanism of HTS, we have adopted a chemico-physical approach by examining the pressure-effect on the superconducting and transport properties of superconducting compound systems. Without exception, all compounds exhibiting superconductivity above 77 K, the boiling point of liquid nitrogen, are anisotropic structures consisting of layers of CuO_2 , metal element (R's; where R is R being Ca, Y or rare-earth element) and metal-oxide (MO's; where M is Ca, Ba, Sr, Cu, Hg, Tl, Bi or Pb). We have investigated under pressure the electrical and superconducting properties of four highly related systems with different R's, different numbers of MO layers, different numbers of CuO _2 layers and various anion dopings. The specific systems studied were: RBa_2Cu _3O_7 (R = Y, Yb, Tm, Ho, Dy, Gd, Sm and Nd), R_{1 -x}Pr_{x}Ba _2Cu_3O _7 (R = Yb and Dy), Y_2Ba _4Cu_{5 + m} O_{13 + m} (m = 1, 2 and 3), and Tl_2Ba _2Ca_{L-1}Cu _{2L-1}O_ {4 + 2L-delta} (L= 1,2 and 3, and 0 <= delta <= 0.1). We found that: (1) in R-123, R affects T _{c} due to its chemical pressure which, in turn, can lead to a modification in the electronic structure of HTS's, in contrast to the general belief that R is isolated from the superconducting CuO_2 layers and hence has no influence on T _{c}; (2) the absence of superconductivity in PrBa_2Cu_3O _7 may be due to the low carrier concentration and hole-localization, in contrast to the suggestion of pair-breaking; (3) there may exist a common optimal T_{c} for all members of the homologous series Y_2Ba _4Cu_{5 + m} O_{13 + m}, raising the possibility of a similar situation in other compound families; and (4) We have observed a universal T _{c}-behavior for HTS's. We believe that these

  17. High Temperature Solid Lubricant Coating for High Temperature Wear Applications

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher (Inventor); Edmonds, Brian J (Inventor)

    2014-01-01

    A self-lubricating, friction and wear reducing composite useful over a wide temperature range is described herein. The composite includes metal bonded chromium oxide dispersed in a metal binder having a substantial amount of nickel. The composite contains a fluoride of at least one Group I, Group II, or rare earth metal, and optionally a low temperature lubricant metal.

  18. High temperature condensates among meteors

    NASA Technical Reports Server (NTRS)

    Wilkening, L. L.

    1975-01-01

    It is noted that two meteors which exhibited no lines of iron or sodium in their spectra have been tentatively attributed to aubrites in order to explain their lack of iron. It is shown, however, that no meteorites, including aubrites, have simultaneously low abundances of iron and sodium and that possible parent materials other than aubrites must be considered for the observed meteors. Other possible parent materials considered in this letter include melilite and diopside, two minerals containing both Ca and Mg but neither Fe nor Na. It is suggested that meteoroids rich in Ca and Mg but lacking Fe and Na might form a reservoir for the so-called 'lost' elements (Ca, Mg, Al, Ti, the lanthanides, and other refractory elements) which are depleted in ordinary and enstatite chondrites relative to cosmic abundances.

  19. Thermal disconnect for high-temperature batteries

    DOEpatents

    Jungst, Rudolph George; Armijo, James Rudolph; Frear, Darrel Richard

    2000-01-01

    A new type of high temperature thermal disconnect has been developed to protect electrical and mechanical equipment from damage caused by operation at extreme temperatures. These thermal disconnects allow continuous operation at temperatures ranging from 250.degree. C. to 450.degree. C., while rapidly terminating operation at temperatures 50.degree. C. to 150.degree. C. higher than the continuous operating temperature.

  20. MEASUREMENTS OF THE RELATIVE ABUNDANCES OF HIGH-ENERGY COSMIC-RAY NUCLEI IN THE TeV/NUCLEON REGION

    SciTech Connect

    Ahn, H. S.; Ganel, O.; Han, J. H.; Kim, K. C.; Lee, M. H.; Malinin, A.; Allison, P. S.; Beatty, J. J.; Brandt, T. J.; Bagliesi, M. G.; Bigongiari, G.; Maestro, P.; Marrocchesi, P. S.; Barbier, L.; Childers, J. T.; DuVernois, M. A.; Conklin, N. B.; Coutu, S.; Jeon, J. A.; Lee, J.

    2010-06-01

    We present measurements of the relative abundances of cosmic-ray nuclei in the energy range of 500-3980 GeV/nucleon from the second flight of the Cosmic Ray Energetics And Mass balloon-borne experiment. Particle energy was determined using a sampling tungsten/scintillating-fiber calorimeter, while particle charge was identified precisely with a dual-layer silicon charge detector installed for this flight. The resulting element ratios C/O, N/O, Ne/O, Mg/O, Si/O, and Fe/O at the top of atmosphere are 0.919 {+-} 0.123{sup stat} {+-} 0.030{sup syst}, 0.076 {+-} 0.019{sup stat} {+-} 0.013{sup syst}, 0.115 {+-} 0.031{sup stat} {+-} 0.004{sup syst}, 0.153 {+-} 0.039{sup stat} {+-} 0.005{sup syst}, 0.180 {+-} 0.045{sup stat} {+-} 0.006{sup syst}, and 0.139 {+-} 0.043{sup stat} {+-} 0.005{sup syst}, respectively, which agree with measurements at lower energies. The source abundance of N/O is found to be 0.054 {+-} 0.013{sup stat} {+-} 0.009{sup syst+0.010esc} {sub -0.017}. The cosmic-ray source abundances are compared to local Galactic (LG) abundances as a function of first ionization potential and as a function of condensation temperature. At high energies the trend that the cosmic-ray source abundances at large ionization potential or low condensation temperature are suppressed compared to their LG abundances continues. Therefore, the injection mechanism must be the same at TeV/nucleon energies as at the lower energies measured by HEAO-3, CRN, and TRACER. Furthermore, the cosmic-ray source abundances are compared to a mixture of 80% solar system abundances and 20% massive stellar outflow (MSO) as a function of atomic mass. The good agreement with TIGER measurements at lower energies confirms the existence of a substantial fraction of MSO material required in the {approx}TeV per nucleon region.

  1. Increased seawater temperature increases the abundance and alters the structure of natural Vibrio populations associated with the coral Pocillopora damicornis

    PubMed Central

    Tout, Jessica; Siboni, Nachshon; Messer, Lauren F.; Garren, Melissa; Stocker, Roman; Webster, Nicole S.; Ralph, Peter J.; Seymour, Justin R.

    2015-01-01

    Rising seawater temperature associated with global climate change is a significant threat to coral health and is linked to increasing coral disease and pathogen-related bleaching events. We performed heat stress experiments with the coral Pocillopora damicornis, where temperature was increased to 31°C, consistent with the 2–3°C predicted increase in summer sea surface maxima. 16S rRNA amplicon sequencing revealed a large shift in the composition of the bacterial community at 31°C, with a notable increase in Vibrio, including known coral pathogens. To investigate the dynamics of the naturally occurring Vibrio community, we performed quantitative PCR targeting (i) the whole Vibrio community and (ii) the coral pathogen Vibrio coralliilyticus. At 31°C, Vibrio abundance increased by 2–3 orders of magnitude and V. coralliilyticus abundance increased by four orders of magnitude. Using a Vibrio-specific amplicon sequencing assay, we further demonstrated that the community composition shifted dramatically as a consequence of heat stress, with significant increases in the relative abundance of known coral pathogens. Our findings provide quantitative evidence that the abundance of potential coral pathogens increases within natural communities of coral-associated microbes as a consequence of rising seawater temperature and highlight the potential negative impacts of anthropogenic climate change on coral reef ecosystems. PMID:26042096

  2. Estimation of high temperature metal-silicate partition coefficients

    NASA Technical Reports Server (NTRS)

    Jones, John H.; Capobianco, Christopher J.; Drake, Michael J.

    1992-01-01

    It has been known for some time that abundances of siderophile elements in the upper mantle of the Earth are far in excess of those expected from equilibrium between metal and silicate at low pressures and temperatures. Murthy (1991) has re-examined this excess of siderophile element problem by estimating liquid metal/liquid silicate partition coefficients reduces from their measured values at a lower temperature, implying that siderophile elements become much less siderophilic at high temperatures. Murthy then draws the important conclusion that metal/silicate equilibrium at high temperatures can account for the abundances of siderophile elements in the Earth's mantle. Of course, his conclusion is critically dependent on the small values of the partition coefficients he calculates. Because the numerical values of most experimentally-determined partition coefficients increase with increasing temperature at both constant oxygen fugacity and at constant redox buffer, we think it is important to try an alternative extrapolation for comparison. We have computed high temperature metal/silicate partition coefficients under a different set of assumptions and show that such long temperature extrapolations yield values which are critically dependent upon the presumed chemical behavior of the siderophile elements in the system.

  3. High Temperature Polyimide Materials in Extreme Temperature Environments

    NASA Technical Reports Server (NTRS)

    Johnson, Theodore F.; Gates, Thomas S.

    2001-01-01

    At the end of the NASA High Speed Research (HSR) Program, NASA Langley Research Center (LaRC) began a program to screen the high-temperature Polymeric Composite Materials (PMCs) characterized by the HSR Durability Program for possible use in Reusable Launch Vehicles (RLVs) operating under extreme temperature conditions. The HSR Program focused on developing material-related technologies to enable a High Speed Civil Transport (HSCT) capable of operating temperatures ranging from 54 C (-65 F) to 177 C (350 F). A high-temperature polymeric resin, PETI-5 was used in the HSR Program to satisfy the requirements for performance and durability for a PMC. For RLVs, it was anticipated that this high temperature material would contribute to reducing the overall weight of a vehicle by eliminating or reducing the thermal protection required to protect the internal structural elements of the vehicle and increasing the structural strain limits. The tests were performed to determine temperature-dependent mechanical and physical proper-ties of IM7/PETI-5 composite over a temperature range from cryogenic temperature -253 C (-423F) to the material's maximum use temperature of 230 C (450 F). This paper presents results from the test program for the temperature-dependent mechanical and physical properties of IM7/PETI-5 composite in the temperature range from -253 C (-423 F) to 27 C (80 F).

  4. M31 GLOBULAR CLUSTER ABUNDANCES FROM HIGH-RESOLUTION, INTEGRATED-LIGHT SPECTROSCOPY

    SciTech Connect

    Colucci, Janet E.; McWilliam, Andrew; Cohen, Judith G. E-mail: sacamero@umich.ed E-mail: andy@ociw.ed

    2009-10-10

    We report the first detailed chemical abundances for five globular clusters (GCs) in M31 from high-resolution (R approx 25,000) spectroscopy of their integrated light (IL). These GCs are the first in a larger set of clusters observed as part of an ongoing project to study the formation history of M31 and its GC population. The data presented here were obtained with the HIRES echelle spectrograph on the Keck I telescope and are analyzed using a new IL spectra analysis method that we have developed. In these clusters, we measure abundances for Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Y, and Ba, ages >=10 Gyr, and a range in [Fe/H] of -0.9 to -2.2. As is typical of Milky Way GCs, we find these M31 GCs to be enhanced in the alpha-elements Ca, Si, and Ti relative to Fe. We also find [Mg/Fe] to be low relative to other [alpha/Fe], and [Al/Fe] to be enhanced in the IL abundances. These results imply that abundances of Mg, Al (and likely O, Na) recovered from IL do display the inter- and intra-cluster abundance variations seen in individual Milky Way GC stars, and that special care should be taken in the future in interpreting low- or high-resolution IL abundances of GCs that are based on Mg-dominated absorption features. Fe-peak and the neutron-capture elements Ba and Y also follow Milky Way abundance trends. We also present high-precision velocity dispersion measurements for all five M31 GCs, as well as independent constraints on the reddening toward the clusters from our analysis.

  5. High-grain diets suppress ruminal tissue abundance of angiopoietin-like protein 4 in cattle.

    PubMed

    Li, S; Yuan, K; Mamedova, L K; Penner, G B; Oba, M; Beauchemin, K A; Bradford, B J

    2014-09-01

    Angiopoietin-like protein 4 (ANGPTL4) is expressed in bovine ruminal epithelium, making it possible that dietary components or commensal microbes may influence gastrointestinal ANGPTL4 production via interactions at the mucosal surface. Therefore, we conducted 3 experiments to evaluate the effects of dietary concentrate level and VFA infusions on ANGPTL4 abundance in ruminal tissue. In Exp. 1, we assigned 12 nonlactating Holstein cows to either 8% or 64% concentrate diets; diets were fed 28 d before euthanasia and ruminal tissue collection. Ruminal tissue and plasma ANGPTL4 protein abundance were unaltered by treatment. In Exp. 2, we assigned 8 continental crossbred heifers to either a 45% or 90% concentrate diet; diets were fed for 75 d before euthanasia and ruminal tissue collection. Compared with the 45% concentrate diet, the 90% concentrate diet decreased (P < 0.01) ruminal tissue ANGPTL4 protein abundance. In Exp. 3, we assigned 6 ruminally cannulated lactating Holstein cows to a treatment sequence in replicated 3 × 3 Latin squares and fed a standard lactation diet. Cows were infused with 5 mol/d sodium acetate, sodium propionate, or sodium butyrate for 2 d. Infusions of VFA did not affect (P > 0.10) mRNA or protein abundance of ANGPTL4 in ruminal papillae. Ruminal papillae ANGPTL4 abundance was, however, negatively correlated with (P = 0.01) ruminal VFA concentrations. ANGPTL4 abundance in ruminal tissue decreases in response to very high dietary concentrate and is inversely correlated with ruminal total VFA concentrations.

  6. Abundance determinations for the F dwarfs members of the Hyades from SOPHIE high resolution spectra

    NASA Astrophysics Data System (ADS)

    Kılıçoǧlu, T.; Monier, R.; Gebran, M.

    2015-12-01

    The mean chemical composition of open clusters can be derived from the chemical abundance analysis of F-type main-sequence stars, as they have convective layers which homogenize the material in their outer layers and thus keep track of the initial composition of the cluster. We present a preliminary abundance analysis of 5 F-type members of the Hyades open cluster using the high resolution spectra retrieved from SOPHIE archive. Our aim is to derive the elemental abundances of these stars as well as the mean abundance distribution of the cluster. The analysis was carried out by iteratively adjusting LTE synthetic spectra for several chemical elements: C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Sr, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu, and Gd. This is the first abundance determination of the Lanthanides in the Hyades F dwarfs. Each element was found to be marginally/slightly overabundant relative to solar, except for Zn, Ga, Y, and Pr which are solar, and for Sr, Ba, La, Ce, Sm, and Gd which are overabundant. The mean iron abundance of the cluster is found to be [Fe/H] = 0.21 dex.

  7. High-temperature thermocouples and related methods

    DOEpatents

    Rempe, Joy L.; Knudson, Darrell L.; Condie, Keith G.; Wilkins, S. Curt

    2011-01-18

    A high-temperature thermocouple and methods for fabricating a thermocouple capable of long-term operation in high-temperature, hostile environments without significant signal degradation or shortened thermocouple lifetime due to heat induced brittleness.

  8. High-temperature borehole instrumentation

    SciTech Connect

    Dennis, B.R.; Koczan, S.P.; Stephani, E.L.

    1985-10-01

    A new method of extracting natural heat from the earth's crust was invented at the Los Alamos National Laboratory in 1970. It uses fluid pressures (hydraulic fracturing) to produce cracks that connect two boreholes drilled into hot rock formations of low initial permeability. Pressurized water is then circulated through this connected underground loop to extract heat from the rock and bring it to the surface. The creation of the fracture reservior began with drilling boreholes deep within the Precambrian basement rock at the Fenton Hill Test Site. Hydraulic fracturing, flow testing, and well-completion operations required unique wellbore measurements using downhole instrumentation systems that would survive the very high borehole temperatures, 320/sup 0/C (610/sup 0/F). These instruments were not available in the oil and gas industrial complex, so the Los Alamos National Laboratory initiated an intense program upgrading existing technology where applicable, subcontracting materials and equipment development to industrial manufactures, and using the Laboratory resource to develop the necessary downhole instruments to meet programmatic schedules. 60 refs., 11 figs.

  9. High Temperature Superconducting Underground Cable

    SciTech Connect

    Farrell, Roger, A.

    2010-02-28

    The purpose of this Project was to design, build, install and demonstrate the technical feasibility of an underground high temperature superconducting (HTS) power cable installed between two utility substations. In the first phase two HTS cables, 320 m and 30 m in length, were constructed using 1st generation BSCCO wire. The two 34.5 kV, 800 Arms, 48 MVA sections were connected together using a superconducting joint in an underground vault. In the second phase the 30 m BSCCO cable was replaced by one constructed with 2nd generation YBCO wire. 2nd generation wire is needed for commercialization because of inherent cost and performance benefits. Primary objectives of the Project were to build and operate an HTS cable system which demonstrates significant progress towards commercial progress and addresses real world utility concerns such as installation, maintenance, reliability and compatibility with the existing grid. Four key technical areas addressed were the HTS cable and terminations (where the cable connects to the grid), cryogenic refrigeration system, underground cable-to-cable joint (needed for replacement of cable sections) and cost-effective 2nd generation HTS wire. This was the world’s first installation and operation of an HTS cable underground, between two utility substations as well as the first to demonstrate a cable-to-cable joint, remote monitoring system and 2nd generation HTS.

  10. High-temperature borehole instrumentation

    NASA Astrophysics Data System (ADS)

    Dennis, B. R.; Koczan, S. P.; Stephani, E. L.

    1985-10-01

    A new method of extracting natural heat from the Earth's crust was invented at the Los Alamos National Laboratory in 1970. It uses fluid pressures (hydraulic fracturing) to produce cracks that connect two boreholes drilled into hot rock formations of low initial permeability. Pressurized water is then circulated through this connected underground loop to extract heat from the rock and bring it to the surface. The creation of the fracture reservior began with drilling boreholes deep within the Precambrian basement rock at the Fenton Hill Test Site. Hydraulic fracturing, flow testing, and well-completion operations required unique wellbore measurements using downhole instrumentation systems that would survive the very high borehole temperatures, 320(0)C (610(0)F). These instruments were not available in the oil and gas industrial complex, so the Los Alamos National Laboratory initiated an intense program upgrading existing technology where applicable, subcontracting materials and equipment development to industrial manufactures, and using the Laboratory resources to develop the necessary downhole instruments to meet programmatic schedules.

  11. High temperature suppression of dioxins.

    PubMed

    Zhan, Ming-Xiu; Chen, Tong; Fu, Jian-Ying; Lin, Xiao-Qing; Lu, Sheng-Yong; Li, Xiao-Dong; Yan, Jian-Hua; Buekens, Alfons

    2016-03-01

    Combined Sulphur-Nitrogen inhibitors, such as sewage sludge decomposition gases (SDG), thiourea and amidosulphonic acid have been observed to suppress the de novo synthesis of dioxins effectively. In this study, the inhibition of PCDD/Fs formation from model fly ash was investigated at unusually high temperatures (650 °C and 850 °C), well above the usual range of de novo tests (250-400 °C). At 650 °C it was found that SDG evolving from dried sewage sludge could suppress the formation of 2,3,7,8-substituted PCDD/Fs with high efficiency (90%), both in weight units and in I-TEQ units. Additionally, at 850 °C, three kinds of sulphur-amine or sulphur-ammonium compounds were tested to inhibit dioxins formation during laboratory-scale tests, simulating municipal solid waste incineration. The suppression efficiencies of PCDD/Fs formed through homogeneous gas phase reactions were all above 85% when 3 wt. % of thiourea (98.7%), aminosulphonic acid (96.0%) or ammonium thiosulphate (87.3%) was added. Differences in the ratio of PCDFs/PCDDs, in weight average chlorination level and in the congener distribution of the 17 toxic PCDD/Fs indicated that the three inhibitors tested followed distinct suppression pathways, possibly in relation to their different functional groups of nitrogen. Furthermore, thiourea reduced the (weight) average chlorinated level. In addition, the thermal decomposition of TUA was studied by means of thermogravimetry-fourier transform infrared spectroscopy (TG-FTIR) and the presence of SO2, SO3, NH3 and nitriles (N≡C bonds) was shown in the decomposition gases; these gaseous inhibitors might be the primary dioxins suppressants.

  12. High Resolution Spectroscopy of Vega-like Stars: Abundances and Circumstellar Gas

    NASA Technical Reports Server (NTRS)

    Dunkin, S. K.; Barlow, M. J.; Ryan, Sean G.

    1996-01-01

    Vega-like stars are main-sequence stars exhibiting excess infrared emission. In an effort to improve the information available on this class of star, 13 stars have been analyzed which have been classed as Vega-like, or have an infra-red excess attributable to dust in their circumstellar environment. In a separate paper stellar properties such as effective temperature and log g have been derived and in this poster we highlight the results of the photospheric abundance analysis also carried out during this work. King recently drew attention to the possible link between Vega-like stars and the photospheric metal-depleted class of A-stars, the Lambda Bootis stars. Since Vega-like stars are thought to have disks of dust, it might be expected that accretion of depleted gas onto the surface of these stars may cause this same phenomenon. In the 6 stars studied for depletions, none showed the extreme underabundance patterns observed in Lambda Bootis stars. However, depletions of silicon and magnesium were found in two of the sample, suggesting that these elements are in silicate dust grains in the circumstellar environment of these stars. Absorption lines attributed to circumstellar gas have been positively identified in three stars in our sample. Individual cases show evidence either of high-velocity outflowing gas, variability in the circumstellar lines observed, or evidence of circumstellar gas in excited lines of Fe II. No previous identification of circumstellar material has been made for two of the stars in question.

  13. High temperature power electronics for space

    NASA Technical Reports Server (NTRS)

    Hammoud, Ahmad N.; Baumann, Eric D.; Myers, Ira T.; Overton, Eric

    1991-01-01

    A high temperature electronics program at NASA Lewis Research Center focuses on dielectric and insulating materials research, development and testing of high temperature power components, and integration of the developed components and devices into a demonstrable 200 C power system, such as inverter. An overview of the program and a description of the in-house high temperature facilities along with experimental data obtained on high temperature materials are presented.

  14. Precipitation and winter temperature predict long-term range-scale abundance changes in Western North American birds.

    PubMed

    Illán, Javier Gutiérrez; Thomas, Chris D; Jones, Julia A; Wong, Weng-Keen; Shirley, Susan M; Betts, Matthew G

    2014-11-01

    Predicting biodiversity responses to climate change remains a difficult challenge, especially in climatically complex regions where precipitation is a limiting factor. Though statistical climatic envelope models are frequently used to project future scenarios for species distributions under climate change, these models are rarely tested using empirical data. We used long-term data on bird distributions and abundance covering five states in the western US and in the Canadian province of British Columbia to test the capacity of statistical models to predict temporal changes in bird populations over a 32-year period. Using boosted regression trees, we built presence-absence and abundance models that related the presence and abundance of 132 bird species to spatial variation in climatic conditions. Presence/absence models built using 1970-1974 data forecast the distributions of the majority of species in the later time period, 1998-2002 (mean AUC = 0.79 ± 0.01). Hindcast models performed equivalently (mean AUC = 0.82 ± 0.01). Correlations between observed and predicted abundances were also statistically significant for most species (forecast mean Spearman's ρ = 0.34 ± 0.02, hindcast = 0.39 ± 0.02). The most stringent test is to test predicted changes in geographic patterns through time. Observed changes in abundance patterns were significantly positively correlated with those predicted for 59% of species (mean Spearman's ρ = 0.28 ± 0.02, across all species). Three precipitation variables (for the wettest month, breeding season, and driest month) and minimum temperature of the coldest month were the most important predictors of bird distributions and abundances in this region, and hence of abundance changes through time. Our results suggest that models describing associations between climatic variables and abundance patterns can predict changes through time for some species, and that changes in precipitation and winter temperature appear to

  15. Precipitation and winter temperature predict long-term range-scale abundance changes in Western North American birds.

    PubMed

    Illán, Javier Gutiérrez; Thomas, Chris D; Jones, Julia A; Wong, Weng-Keen; Shirley, Susan M; Betts, Matthew G

    2014-11-01

    Predicting biodiversity responses to climate change remains a difficult challenge, especially in climatically complex regions where precipitation is a limiting factor. Though statistical climatic envelope models are frequently used to project future scenarios for species distributions under climate change, these models are rarely tested using empirical data. We used long-term data on bird distributions and abundance covering five states in the western US and in the Canadian province of British Columbia to test the capacity of statistical models to predict temporal changes in bird populations over a 32-year period. Using boosted regression trees, we built presence-absence and abundance models that related the presence and abundance of 132 bird species to spatial variation in climatic conditions. Presence/absence models built using 1970-1974 data forecast the distributions of the majority of species in the later time period, 1998-2002 (mean AUC = 0.79 ± 0.01). Hindcast models performed equivalently (mean AUC = 0.82 ± 0.01). Correlations between observed and predicted abundances were also statistically significant for most species (forecast mean Spearman's ρ = 0.34 ± 0.02, hindcast = 0.39 ± 0.02). The most stringent test is to test predicted changes in geographic patterns through time. Observed changes in abundance patterns were significantly positively correlated with those predicted for 59% of species (mean Spearman's ρ = 0.28 ± 0.02, across all species). Three precipitation variables (for the wettest month, breeding season, and driest month) and minimum temperature of the coldest month were the most important predictors of bird distributions and abundances in this region, and hence of abundance changes through time. Our results suggest that models describing associations between climatic variables and abundance patterns can predict changes through time for some species, and that changes in precipitation and winter temperature appear to

  16. Chemical abundances in high-redshift galaxies: a powerful new emission line diagnostic

    NASA Astrophysics Data System (ADS)

    Dopita, Michael A.; Kewley, Lisa J.; Sutherland, Ralph S.; Nicholls, David C.

    2016-02-01

    This Letter presents a new, remarkably simple diagnostic specifically designed to derive chemical abundances for high redshift galaxies. It uses only the Hα, [N ii] and [S ii] emission lines, which can usually be observed in a single grating setting, and is almost linear up to an abundance of 12+log (O/H) = 9.05. It can be used over the full abundance range encountered in high redshift galaxies. By its use of emission lines located close together in wavelength, it is also independent of reddening. Our diagnostic depends critically on the calibration of the N/O ratio. However, by using realistic stellar atmospheres combined with the N/O vs. O/H abundance calibration derived locally from stars and H ii regions, and allowing for the fact that high-redshift H ii regions have both high ionisation parameters and high gas pressures, we find that the observations of high-redshift galaxies can be simply explained by the models without having to invoke arbitrary changes in N/O ratio, or the presence of unusual quantities of Wolf-Rayet stars in these galaxies.

  17. 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.

  18. High-Sensitivity Temperature Measurement

    ERIC Educational Resources Information Center

    Leadstone, G. S.

    1978-01-01

    Describes a method of measuring small temperature differences that amount to a .01K, using an arrangement of a copper-constantan thermocouple, a microamplifier and a galvanometer, as an indirect way of measuring heat energy. (GA)

  19. Response of pigeon guillemots to variable abundance of high-lipid and low-lipid prey

    USGS Publications Warehouse

    Litzow, M.A.; Piatt, J.F.; Prichard, A.K.; Roby, D.D.

    2002-01-01

    Populations of the pigeon guillemot (Cepphus columba) and other piscivores have been in decline for several decades in the Gulf of Alaska and Bering Sea, and a decline in abundance of lipid-rich schooling fishes is hypothesized as the major cause. We tested this hypothesis by studying the breeding biology of pigeon guillemots during 1995-1999 while simultaneously measuring prey abundance with beach seines and bottom trawls. Our study area (Kachemak Bay, Alaska) comprises two oceanographically distinct areas. Populations of a lipid-rich schooling fish, Pacific sand lance (Ammodytes hexapterus), were higher in the warmer Inner Bay than in the colder Outer Bay, and sand lance abundance was higher during warm years. Populations of low-lipid content demersal fishes were similar between areas. Chick survival to age 15 days was 47% higher in the Inner Bay (high-lipid diet) than in the Outer Bay (low-lipid diet), and estimated reproductive success (chicks fledged nest-1) was 62% higher in the Inner Bay than in the Outer Bay. Chick provisioning rate (kJ chick-1 h-1) increased with the proportion of sand lance in the diet (r2=0.21), as did growth rate (g day-1) of younger (beta) chicks in two-chick broods (r2=0.14). Pigeon guillemots in the Inner Bay switched to demersal prey during years of below-average sand lance abundance, and these birds reacted to 38-fold interannual changes in sand lance abundance with reductions in beta chick growth rates, with no decline in beta chick survival. In contrast, the proportion of nests experiencing brood reduction in the Outer Bay (demersal diet) increased >300% during years of below-average demersal abundance, although demersal fish abundance varied only 4-fold among years. Our results support the hypothesis that recovery of pigeon guillemot populations from the effects of the Exxon Valdez oil spill is limited by availability of lipid-rich prey.

  20. Measurement of thermodynamic temperature of high temperature fixed points

    SciTech Connect

    Gavrilov, V. R.; Khlevnoy, B. B.; Otryaskin, D. A.; Grigorieva, I. A.; Samoylov, M. L.; Sapritsky, V. I.

    2013-09-11

    The paper is devoted to VNIIOFI's measurements of thermodynamic temperature of the high temperature fixed points Co-C, Pt-C and Re-C within the scope of the international project coordinated by the Consultative Committee for Thermometry working group 5 'Radiation Thermometry'. The melting temperatures of the fixed points were measured by a radiance mode radiation thermometer calibrated against a filter radiometer with known irradiance spectral responsivity via a high temperature black body. This paper describes the facility used for the measurements, the results and estimated uncertainties.

  1. High Varroa mite abundance influences chemical profiles of worker bees and mite-host preferences.

    PubMed

    Cervo, R; Bruschini, C; Cappa, F; Meconcelli, S; Pieraccini, G; Pradella, D; Turillazzi, S

    2014-09-01

    Honeybee disappearance is one of the major environmental and economic challenges this century has to face. The ecto-parasitic mite Varroa destructor represents one of the main causes of the worldwide beehive losses. Although halting mite transmission among beehives is of primary importance to save honeybee colonies from further decline, the natural route used by mites to abandon a collapsing colony has not been extensively investigated so far. Here, we explored whether, with increasing mite abundance within the colony, mites change their behaviour to maximize the chances of leaving a highly infested colony. We show that, at low mite abundance, mites remain within the colony and promote their reproduction by riding nurses that they distinguish from foragers by different chemical cuticular signatures. When mite abundance increases, the chemical profile of nurses and foragers tends to overlap, promoting mite departure from exploited colonies by riding pollen foragers. PMID:25165133

  2. Simultaneous Quantification of Temperature, Pyroxenite Abundance, and Upwelling Rates in the Iceland Mantle Source

    NASA Astrophysics Data System (ADS)

    Brown, E.; Lesher, C. E.

    2014-12-01

    The compositions and volumes of basalts erupted at the earth's surface are a function of mantle temperature, mantle composition, and the rate at which the mantle upwells through the melting zone. Thus, basaltic magmatism has long been used to probe the thermal and physiochemical state of the earth's mantle. Great insight has been gained into the mantle beneath the global spreading ridge system, where the mantle source is assumed to be homogeneous peridotite that upwells passively [1]. However, it is now recognized that many basalt source regions are lithologically heterogeneous (i.e. containing recycled lithospheric material ranging from harzburgite to pyroxenite) and upwell at rates in excess of those governed by plate separation. To account for these complexities, we have developed a forward melting model for lithologically heterogeneous mantle that incorporates thermodynamically and experimentally constrained melting functions for a range of peridotite and pyroxenite lithologies. The model is unique because it quantifies mantle upwelling rates based on the net buoyancy of the source, thus providing a means for linking basalt compositions/volumes to mantle flow while accounting for source heterogeneity. We apply the model to investigate the mantle properties governing magmatism along different rift segments in Iceland, where lithologic heterogeneity and variable upwelling rates have been inferred through geochemical means [2,3]. Using constraints from seismically determined crustal thicknesses and recent estimates of the proportion of pyroxenite-derived melt contributing to Icelandic basalt compositions [4,5], we show that mantle sources beneath Iceland have excess potential temperatures >85 °C, contain <7% pyroxenite, and maximum upwelling rates ~14 times the passive rate. Our modeling highlights the dominant role of elevated mantle temperature and enhanced upwelling for high productivity magmatism in Iceland, and a subordinate role for mantle heterogeneity

  3. High Temperature Filler for Tile Gaps

    NASA Technical Reports Server (NTRS)

    Holt, J. W.; Wang, D. S.

    1983-01-01

    Gaps between ceramic tiles filled with ceramic-coated fabric that withstands temperatures as high as 2,000 degrees F (1,300 degrees C). Reusable high-temperature gap filler is made of fabric coated with ceramic slurry and bonded in place with room-temperature-vulcanized adhesive. Procedure used in kilns and furnaces.

  4. High temperature superconducting fault current limiter

    DOEpatents

    Hull, John R.

    1997-01-01

    A fault current limiter (10) for an electrical circuit (14). The fault current limiter (10) includes a high temperature superconductor (12) in the electrical circuit (14). The high temperature superconductor (12) is cooled below its critical temperature to maintain the superconducting electrical properties during operation as the fault current limiter (10).

  5. High temperature superconducting fault current limiter

    DOEpatents

    Hull, J.R.

    1997-02-04

    A fault current limiter for an electrical circuit is disclosed. The fault current limiter includes a high temperature superconductor in the electrical circuit. The high temperature superconductor is cooled below its critical temperature to maintain the superconducting electrical properties during operation as the fault current limiter. 15 figs.

  6. Young Stars and Ionized Nebulae in M83: Comparing Chemical Abundances at High Metallicity.

    NASA Astrophysics Data System (ADS)

    Bresolin, Fabio; Kudritzki, Rolf-Peter; Urbaneja, Miguel A.; Gieren, Wolfgang; Ho, I.-Ting; Pietrzyński, Grzegorz

    2016-10-01

    We present spectra of 14 A-type supergiants in the metal-rich spiral galaxy M83. We derive stellar parameters and metallicities and measure a spectroscopic distance modulus μ =28.47+/- 0.10 (4.9 ± 0.2 Mpc), in agreement with other methods. We use the stellar characteristic metallicity of M83 and other systems to discuss a version of the galaxy mass–metallicity relation that is independent of the analysis of nebular emission lines and the associated systematic uncertainties. We reproduce the radial metallicity gradient of M83, which flattens at large radii, with a chemical evolution model, constraining gas inflow and outflow processes. We carry out a comparative analysis of the metallicities we derive from the stellar spectra and published H ii region line fluxes, utilizing both the direct, {T}{{e}}-based method and different strong-line abundance diagnostics. The direct abundances are in relatively good agreement with the stellar metallicities, once we apply a modest correction to the nebular oxygen abundance due to depletion onto dust. Popular empirically calibrated strong-line diagnostics tend to provide nebular abundances that underestimate the stellar metallicities above the solar value by ∼0.2 dex. This result could be related to difficulties in selecting calibration samples at high metallicity. The O3N2 method calibrated by Pettini and Pagel gives the best agreement with our stellar metallicities. We confirm that metal recombination lines yield nebular abundances that agree with the stellar abundances for high-metallicity systems, but find evidence that in more metal-poor environments they tend to underestimate the stellar metallicities by a significant amount, opposite to the behavior of the direct method.

  7. High temperature ceramic interface study

    NASA Technical Reports Server (NTRS)

    Lindberg, L. J.

    1984-01-01

    Monolithic SiC and Si3N4 are susceptible to contact stress damage at static and sliding interfaces. Transformation-toughened zirconia (TTZ) was evaluated under sliding contact conditions to determine if the higher material fracture toughness would reduce the susceptibility to contact stress damage. Contact stress tests were conducted on four commercially available TTZ materials at normal loads ranging from 0.455 to 22.7 kg (1 to 50 pounds) at temperatures ranging from room temperature to 1204C (2200 F). Static and dynamic friction were measured as a function of temperature. Flexural strength measurements after these tests determined that the contact stress exposure did not reduce the strength of TTZ at contact loads of 0.455, 4.55, and 11.3 kg (1, 10, and 25 pounds). Prior testing with the lower toughness SiC and Si3N4 materials resulted in a substantial strength reduction at loads of only 4.55 and 11.3 kg (10 and 25 pounds). An increase in material toughness appears to improve ceramic material resistance to contact stress damage. Baseline material flexure strength was established and the stress rupture capability of TTZ was evaluated. Stress rupture tests determined that TTZ materials are susceptible to deformation due to creep and that aging of TTZ materials at elevated temperatures results in a reduction of material strength.

  8. Deep Trek High Temperature Electronics Project

    SciTech Connect

    Bruce Ohme

    2007-07-31

    This report summarizes technical progress achieved during the cooperative research agreement between Honeywell and U.S. Department of Energy to develop high-temperature electronics. Objects of this development included Silicon-on-Insulator (SOI) wafer process development for high temperature, supporting design tools and libraries, and high temperature integrated circuit component development including FPGA, EEPROM, high-resolution A-to-D converter, and a precision amplifier.

  9. Two-Point Observations of High- and Low-Frequency Variations of Helium Abundance in the Solar Win

    NASA Astrophysics Data System (ADS)

    Safrankova, J.; Cagas, P.; Nemecek, Z.; Prech, L.; Zastenker, G. N.; Riazantseva, M.

    2014-12-01

    Variations of the abundance of heavy species observed in the solar wind are usually attributed to spacecraft encounters with streams emanating from different places and altitudes in the source region and their further evolution is considered as being negligible. These conclusions are based on an analysis of highly averaged data and much less attention was devoted to variations on the time scale of seconds. The BMSW instrument onboard the Spektr-R spacecraft provides a high-time resolution data of the helium and proton fluxes and proton velocity, density, and temperature that suitable for investigations of rapid variations. The paper compares measurements in two points (Spektr-R and Wind) and focuses on the changes of helium abundance on this middle scale and on their correlations with variations of other parameters. We have found that only a low-frequency part of He abundance variations can be attributed to changes of the source region, whereas a significant portion of them could be generated by in-transit turbulence that is probably driven by the speed difference between the ion species.

  10. High-dispersion spectroscopy of giants in metal-poor globular clusters. I - Iron abundances

    NASA Technical Reports Server (NTRS)

    Minniti, Dante; Geisler, Doug; Peterson, Ruth C.; Claria, Juan J.

    1993-01-01

    High-resolution, high-SNR CCD spectra have been obtained for 16 giants in eight metal-poor Galactic globular clusters. Fe abundances accurate to 0.15 dex have been determined by a fully consistent set of model atmospheres and spectrum synthesis techniques. A metallicity scale is presented for metal-poor clusters that should prove useful for calibrating a wide variety of photometric and low-resolution spectroscopic metallicity indicators.

  11. High temperature tensile testing of ceramic composites

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, John Z.; Hemann, John H.

    1988-01-01

    The various components of a high temperature tensile testing system are evaluated. The objective is the high temperature tensile testing of SiC fiber reinforced reaction bonded Si3N4 specimens at test temperatures up to 1650 C (3000 F). Testing is to be conducted in inert gases and air. Gripping fixtures, specimen configurations, furnaces, optical strain measuring systems, and temperature measurement techniques are reviewed. Advantages and disadvantages of the various techniques are also noted.

  12. Detailed chemical abundances of extragalactic globular clusters using high resolution, integrated light spectra

    NASA Astrophysics Data System (ADS)

    Colucci, Janet E.

    Globular clusters (GCs) are luminous, observationally accessible objects that are good tracers of the total star formation and evolutionary history of galaxies. We present the first detailed chemical abundances for GCs in M31 using a new abundance analysis technique designed for high resolution, integrated light (IL) spectra of GCs. This technique has recently been developed using a training set of old GCS in the Milky Way (MW), and makes possible detailed chemical evolution studies of distant galaxies, where high resolution abundance analysis of individual stars are not obtainable. For the 5 M31 GCs presented here, we measure abundances of 14 elements: Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Y, and Ba. We find the M31 GCs have ages (>10 Gyr) and chemical properties similar to MW GCs, including an enhancement in the alpha-elements Ca, Ti and Si of [alpha/Fe]˜ +0.4. In this thesis, we also further develop this IL abundance analysis method to include GCs of ages 10 Myr--12 Gyrs using GCs in the Large Magellanic Cloud (LMC), which contains the necessary sample of clusters over this wide age range. This work demonstrates for the first time that this IL abundance analysis method can be used on clusters of all ages, and that ages can be constrained to within 1--2 Gyr for clusters with ages of ˜2 Gyr and within a few 100 Myr for clusters with ages <1 Gyr. We find that we can measure [Fe/H] in clusters with ages <12 Gyrs with similar or only slightly larger uncertainties (0.1--0.25 dex) than those obtained for old GCs; the slightly larger uncertainties are due to the rapid evolution in stellar populations at these ages. Using the LMC clusters, we also investigate the effects of statistical fluctuations in the theoretical cluster stellar populations used in our analysis. We also develop strategies to allow for statistical variations in these stellar populations, and find that the stability of the Fe line abundance solution can provide tight constraints on the

  13. Dynamic, High-Temperature, Flexible Seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M.; Sirocky, Paul J.

    1989-01-01

    New seal consists of multiple plies of braided ceramic sleeves filled with small ceramic balls. Innermost braided sleeve supported by high-temperature-wire-mesh sleeve that provides both springback and preload capabilities. Ceramic balls reduce effect of relatively high porosity of braided ceramic sleeves by acting as labyrinth flow path for gases and thereby greatly increasing pressure gradient seal can sustain. Dynamic, high-temperature, flexible seal employed in hypersonic engines, two-dimensional convergent/divergent and vectorized-thrust exhaust nozzles, reentry vehicle airframes, rocket-motor casings, high-temperature furnaces, and any application requiring non-asbestos high-temperature gaskets.

  14. High-model abundance may permit the gradual evolution of Batesian mimicry: an experimental test.

    PubMed

    Kikuchi, David W; Pfennig, David W

    2010-04-01

    In Batesian mimicry, a harmless species (the 'mimic') resembles a dangerous species (the 'model') and is thus protected from predators. It is often assumed that the mimetic phenotype evolves from a cryptic phenotype, but it is unclear how a population can transition through intermediate phenotypes; such intermediates may receive neither the benefits of crypsis nor mimicry. Here, we ask if selection against intermediates weakens with increasing model abundance. We also ask if mimicry has evolved from cryptic phenotypes in a mimetic clade. We first present an ancestral character-state reconstruction showing that mimicry of a coral snake (Micrurus fulvius) by the scarlet kingsnake (Lampropeltis elapsoides) evolved from a cryptic phenotype. We then evaluate predation rates on intermediate phenotypes relative to cryptic and mimetic phenotypes under conditions of both high- and low-model abundances. Our results indicate that where coral snakes are rare, intermediate phenotypes are attacked more often than cryptic and mimetic phenotypes, indicating the presence of an adaptive valley. However, where coral snakes are abundant, intermediate phenotypes are not attacked more frequently, resulting in an adaptive landscape without a valley. Thus, high-model abundance may facilitate the evolution of Batesian mimicry.

  15. First high-precision differential abundance analysis of extremely metal-poor stars

    NASA Astrophysics Data System (ADS)

    Reggiani, Henrique; Meléndez, Jorge; Yong, David; Ramírez, Ivan; Asplund, Martin

    2016-02-01

    Context. Studies of extremely metal-poor stars indicate that chemical abundance ratios [X/Fe] have a root mean square scatter as low as 0.05 dex (12%). It remains unclear whether this reflects observational uncertainties or intrinsic astrophysical scatter arising from physical conditions in the interstellar medium at early times. Aims: We measure differential chemical abundance ratios in extremely metal-poor stars to investigate the limits of precision and to understand whether cosmic scatter or observational errors are dominant. Methods: We used high-resolution (R ~ 95 000) and high signal-to-noise (S/N = 700 at 5000 Å) HIRES/Keck spectra to determine high-precision differential abundances between two extremely metal-poor stars through a line-by-line differential approach. We determined stellar parameters for the star G64-37 with respect to the standard star G64-12. We performed EW measurements for the two stars for the lines recognized in both stars and performed spectral synthesis to study the carbon abundances. Results: The differential approach allowed us to obtain errors of σ(Teff) = 27 K, σ(log g) = 0.06 dex, σ( [Fe/H] ) = 0.02 dex and σ(vt) = 0.06 km s-1. We estimated relative chemical abundances with a precision as low as σ([X/Fe]) ≈ 0.01 dex. The small uncertainties demonstrate that there are genuine abundance differences larger than the measurement errors. The observed Li difference cannot be explained by the difference in mass because the less massive star has more Li. Conclusions: It is possible to achieve an abundance precision around ≈ 0.01-0.05 dex for extremely metal-poor stars, which opens new windows on the study of the early chemical evolution of the Galaxy. Table A.1 is also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/586/A67

  16. Stable Vanadium Isotope Fractionation at High Temperatures

    NASA Astrophysics Data System (ADS)

    Prytulak, J.; Parkinson, I. J.; Savage, P. S.; Nielsen, S. G.; Halliday, A. N.

    2011-12-01

    Vanadium is a redox sensitive transition metal existing in multiple valence states at terrestrial conditions. Stable vanadium isotopes (reported as δ51V in % relative to an Alfa Aesar standard [1]) are a potentially powerful tracer of oxidation-reduction processes. However, the determination of δ51V is analytically challenging, primarily due to the extreme abundance ratio between the only two stable isotopes (51V/50V ~ 400) and, also, significant isobaric interferences of 50Ti and 50Cr on the minor 50V isotope. We have developed the first method able to determine δ51V to a precision (2 s.d. ~ 0.15%, [1,2]) that enables application of this isotope system to geological processes. To usefully investigate high temperature processes using vanadium isotopes, knowledge of the isotope composition and range of values present in the ambient mantle is required. Here we discuss the first δ51V measured in igneous materials encompassing peridotites, MORB, and primitive mantle-derived melts such as picrites. This first dataset provides a preliminary reconnaissance of the magnitude of natural fractionation. We find little isotope fractionation in suites of peridotites and MORB (< 0.5 %). However, the small but analytically significant variation appears to be related to secondary processes, with extremely altered peridotites consistently displaying slightly heavier isotope compositions. We find no resolvable δ51V variation between fresh MORB glass and fresh peridotite. Intriguingly, a suite of subduction-related peridotites from the Mariana forearc, previously characterized for fO2 [3], do not display the predicted co-variation between δ51V and fO2, but instead also have compositions identical to MORB glass. This nominally supports recent indications that there is limited difference in the oxygen fugacity of the MORB source and the subarc mantle wedge [e.g., 4, 5]. Finally, we observe large δ51V variations (~ 2 %) in a suite of evolving lavas from Hekla volcano, Iceland

  17. High temperature silicon carbide impregnated insulating fabrics

    NASA Technical Reports Server (NTRS)

    Schomburg, C.; Dotts, R. L. (Inventor)

    1982-01-01

    High temperature insulating articles having improved performance characteristics are described. The articles comprise fabrics of closely woven refractory or heat resistant fibers having particles of silicon carbide dispersed at least partially through the fabric and bonded to the fibers with an emulsifiable polyethylene wax. Such articles exhibit significantly increased high temperature emittance characteristics and an improved retention of integrity and flexibility after prolonged exposure to high temperature.

  18. Advanced high-temperature batteries

    NASA Technical Reports Server (NTRS)

    Nelson, P. A.

    1989-01-01

    Recent results for Li-Al/FeS2 cells and bipolar battery design have shown the possibility of achieving high specific energy (210 Wh/kg) and high specific power (239 W/kg) at the cell level for an electric vehicle application. Outstanding performance is also projected for sodium/metal chloride cells having large electrolyte areas and thin positive electrodes.

  19. Depletion of Abundant Sequences by Hybridization (DASH): using Cas9 to remove unwanted high-abundance species in sequencing libraries and molecular counting applications.

    PubMed

    Gu, W; Crawford, E D; O'Donovan, B D; Wilson, M R; Chow, E D; Retallack, H; DeRisi, J L

    2016-03-04

    Next-generation sequencing has generated a need for a broadly applicable method to remove unwanted high-abundance species prior to sequencing. We introduce DASH (Depletion of Abundant Sequences by Hybridization). Sequencing libraries are 'DASHed' with recombinant Cas9 protein complexed with a library of guide RNAs targeting unwanted species for cleavage, thus preventing them from consuming sequencing space. We demonstrate a more than 99 % reduction of mitochondrial rRNA in HeLa cells, and enrichment of pathogen sequences in patient samples. We also demonstrate an application of DASH in cancer. This simple method can be adapted for any sample type and increases sequencing yield without additional cost.

  20. Depletion of Abundant Sequences by Hybridization (DASH): using Cas9 to remove unwanted high-abundance species in sequencing libraries and molecular counting applications.

    PubMed

    Gu, W; Crawford, E D; O'Donovan, B D; Wilson, M R; Chow, E D; Retallack, H; DeRisi, J L

    2016-01-01

    Next-generation sequencing has generated a need for a broadly applicable method to remove unwanted high-abundance species prior to sequencing. We introduce DASH (Depletion of Abundant Sequences by Hybridization). Sequencing libraries are 'DASHed' with recombinant Cas9 protein complexed with a library of guide RNAs targeting unwanted species for cleavage, thus preventing them from consuming sequencing space. We demonstrate a more than 99 % reduction of mitochondrial rRNA in HeLa cells, and enrichment of pathogen sequences in patient samples. We also demonstrate an application of DASH in cancer. This simple method can be adapted for any sample type and increases sequencing yield without additional cost. PMID:26944702

  1. FIRST SPECTROSCOPIC EVIDENCE FOR HIGH IONIZATION STATE AND LOW OXYGEN ABUNDANCE IN Ly{alpha} EMITTERS ,

    SciTech Connect

    Nakajima, Kimihiko; Shimasaku, Kazuhiro; Hashimoto, Takuya; Ono, Yoshiaki; Ouchi, Masami; Lee, Janice C.

    2013-05-20

    We present results from Keck/NIRSPEC and Magellan/MMIRS follow-up spectroscopy of Ly{alpha} emitters (LAEs) at z = 2.2 identified in our Subaru narrowband survey. We successfully detect H{alpha} emission from seven LAEs, and perform a detailed analysis of six LAEs free from active galactic nucleus activity, two out of which, CDFS-3865 and COSMOS-30679, have [O II] and [O III] line detections. They are the first [O II]-detected LAEs at high-z, and their [O III]/[O II] ratios and R23-indices provide the first simultaneous determinations of ionization parameter and oxygen abundance for LAEs. CDFS-3865 has a very high ionization parameter (q{sub ion}=2.5{sup +1.7}{sub -0.8} Multiplication-Sign 10{sup 8} cm s{sup -1}) and a low oxygen abundance (12+ log (O/H)=7.84{sup +0.24}{sub -0.25}) in contrast with moderate values of other high-z galaxies such as Lyman break galaxies (LBGs). COSMOS-30679 also possesses a relatively high ionization parameter (q{sub ion}=8{sup +10}{sub -4} Multiplication-Sign 10{sup 7} cm s{sup -1}) and a low oxygen abundance (12+ log (O/H)=8.18{sup +0.28}{sub -0.28}). Both LAEs appear to fall below the mass-metallicity relation of z {approx} 2 LBGs. Similarly, a low metallicity of 12 + log (O/H) < 8.4 is independently indicated for typical LAEs from a composite spectrum and the [N II]/H{alpha} index. Such high ionization parameters and low oxygen abundances can be found in local star-forming galaxies, but this extreme local population occupies only {approx}0.06% of the Sloan Digital Sky Survey spectroscopic galaxy sample with a number density {approx}100 times smaller than that of LAEs. With their high ionization parameters and low oxygen abundances, LAEs would represent an early stage of galaxy formation dominated by massive stars in compact star-forming regions. High-q{sub ion} galaxies like LAEs would produce ionizing photons efficiently with a high escape fraction achieved by density-bounded H II regions, which would significantly contribute to

  2. Investigations into High Temperature Components and Packaging

    SciTech Connect

    Marlino, L.D.; Seiber, L.E.; Scudiere, M.B.; M.S. Chinthavali, M.S.; McCluskey, F.P.

    2007-12-31

    The purpose of this report is to document the work that was performed at the Oak Ridge National Laboratory (ORNL) in support of the development of high temperature power electronics and components with monies remaining from the Semikron High Temperature Inverter Project managed by the National Energy Technology Laboratory (NETL). High temperature electronic components are needed to allow inverters to operate in more extreme operating conditions as required in advanced traction drive applications. The trend to try to eliminate secondary cooling loops and utilize the internal combustion (IC) cooling system, which operates with approximately 105 C water/ethylene glycol coolant at the output of the radiator, is necessary to further reduce vehicle costs and weight. The activity documented in this report includes development and testing of high temperature components, activities in support of high temperature testing, an assessment of several component packaging methods, and how elevated operating temperatures would impact their reliability. This report is organized with testing of new high temperature capacitors in Section 2 and testing of new 150 C junction temperature trench insulated gate bipolar transistor (IGBTs) in Section 3. Section 4 addresses some operational OPAL-GT information, which was necessary for developing module level tests. Section 5 summarizes calibration of equipment needed for the high temperature testing. Section 6 details some additional work that was funded on silicon carbide (SiC) device testing for high temperature use, and Section 7 is the complete text of a report funded from this effort summarizing packaging methods and their reliability issues for use in high temperature power electronics. Components were tested to evaluate the performance characteristics of the component at different operating temperatures. The temperature of the component is determined by the ambient temperature (i.e., temperature surrounding the device) plus the

  3. Development of high temperature strain gages

    NASA Technical Reports Server (NTRS)

    Lemcoe, M. M.

    1973-01-01

    High temperature electric resistance wire strain gages were developed and evaluated for use at temperatures exceeding 922 K (1200 F). A special high temperature strain gage alloy (Fe-25Cr-7.5A1), designated BCL-3, was used to fabricate the gages. Pertinent gage characteristics were determined at temperatures up to 1255 K (1800 F). The results of the evaluation were reported in graphical and tabular form. It was concluded that the gages will perform satisfactorily at temperatures to at least 1089 K (1500 F) for at least one hour.

  4. Nuclear fuels for very high temperature applications

    SciTech Connect

    Lundberg, L.B.; Hobbins, R.R.

    1992-01-01

    The success of the development of nuclear thermal propulsion devices and thermionic space nuclear power generation systems depends on the successful utilization of nuclear fuel materials at temperatures in the range 2000 to 3500 K. Problems associated with the utilization of uranium bearing fuel materials at these very high temperatures while maintaining them in the solid state for the required operating times are addressed. The critical issues addressed include evaporation, melting, reactor neutron spectrum, high temperature chemical stability, fabrication, fission induced swelling, fission product release, high temperature creep, thermal shock resistance, and fuel density, both mass and fissile atom. Candidate fuel materials for this temperature range are based on UO{sub 2} or uranium carbides. Evaporation suppression, such as a sealed cladding, is required for either fuel base. Nuclear performance data needed for design are sparse for all candidate fuel forms in this temperature range, especially at the higher temperatures.

  5. Nuclear fuels for very high temperature applications

    SciTech Connect

    Lundberg, L.B.; Hobbins, R.R.

    1992-08-01

    The success of the development of nuclear thermal propulsion devices and thermionic space nuclear power generation systems depends on the successful utilization of nuclear fuel materials at temperatures in the range 2000 to 3500 K. Problems associated with the utilization of uranium bearing fuel materials at these very high temperatures while maintaining them in the solid state for the required operating times are addressed. The critical issues addressed include evaporation, melting, reactor neutron spectrum, high temperature chemical stability, fabrication, fission induced swelling, fission product release, high temperature creep, thermal shock resistance, and fuel density, both mass and fissile atom. Candidate fuel materials for this temperature range are based on UO{sub 2} or uranium carbides. Evaporation suppression, such as a sealed cladding, is required for either fuel base. Nuclear performance data needed for design are sparse for all candidate fuel forms in this temperature range, especially at the higher temperatures.

  6. Corrosion Resistant Coatings for High Temperature Applications

    SciTech Connect

    Besman, T.M.; Cooley, K.M.; Haynes, J.A.; Lee, W.Y.; Vaubert, V.M.

    1998-12-01

    Efforts to increase efficiency of energy conversion devices have required their operation at ever higher temperatures. This will force the substitution of higher-temperature structural ceramics for lower temperature materials, largely metals. Yet, many of these ceramics will require protection from high temperature corrosion caused by combustion gases, atmospheric contaminants, or the operating medium. This paper discusses examples of the initial development of such coatings and materials for potential application in combustion, aluminum smelting, and other harsh environments.

  7. Spin Hall magnetoresistance at high temperatures

    SciTech Connect

    Uchida, Ken-ichi; Qiu, Zhiyong; Kikkawa, Takashi; Iguchi, Ryo; Saitoh, Eiji

    2015-02-02

    The temperature dependence of spin Hall magnetoresistance (SMR) in Pt/Y{sub 3}Fe{sub 5}O{sub 12} (YIG) bilayer films has been investigated in a high temperature range from room temperature to near the Curie temperature of YIG. The experimental results show that the magnitude of the magnetoresistance ratio induced by the SMR monotonically decreases with increasing the temperature and almost disappears near the Curie temperature. We found that, near the Curie temperature, the temperature dependence of the SMR in the Pt/YIG film is steeper than that of a magnetization curve of the YIG; the critical exponent of the magnetoresistance ratio is estimated to be 0.9. This critical behavior of the SMR is attributed mainly to the temperature dependence of the spin-mixing conductance at the Pt/YIG interface.

  8. The Distribution and Abundance of Parasites in Aquatic Ecosystems in a Changing Climate: More than Just Temperature.

    PubMed

    Marcogliese, David J

    2016-10-01

    SynopsisEvaluation of the potential response of parasites of aquatic organisms to climate change illustrates the complexity of host-parasite relationships and the difficulty of making accurate predictions for these biological systems. In recent years, trematodes have proven to be a useful model to evaluate potential effects of climate change on host-parasite systems. In the first part of this article, I review and summarize results from the recent use of trematodes and specifically their early life cycle stages in testing effects of temperature and other climate-driven variables on life history traits and host-parasite interactions. However, metazoan parasites in aquatic systems respond directly to changes in temperature and also to changes in other climate-driven abiotic parameters that are mediated directly on the parasite or indirectly through changes in the distribution and abundance of their hosts. In addition, though most research to date has focused on the effects of temperature, it is imperative to explore effects of precipitation, eutrophication, acidification, water levels and flow rates, habitat loss and fragmentation, extreme weather, and other forms of anthropogenic interference on the distribution of both hosts and parasites, as these biotic and abiotic factors and stressors do not operate independently of climate. In the second part of this article, the effects of some of these factors derived from our own field studies, as well as other investigations both in the laboratory and the field, on the distribution, abundance, and community structure of parasites in aquatic ecosystems will be reviewed and discussed.

  9. Borehole Stability in High-Temperature Formations

    NASA Astrophysics Data System (ADS)

    Yan, Chuanliang; Deng, Jingen; Yu, Baohua; Li, Wenliang; Chen, Zijian; Hu, Lianbo; Li, Yang

    2014-11-01

    In oil and gas drilling or geothermal well drilling, the temperature difference between the drilling fluid and formation will lead to an apparent temperature change around the borehole, which will influence the stress state around the borehole and tend to cause borehole instability in high geothermal gradient formations. The thermal effect is usually not considered as a factor in most of the conventional borehole stability models. In this research, in order to solve the borehole instability in high-temperature formations, a calculation model of the temperature field around the borehole during drilling is established. The effects of drilling fluid circulation, drilling fluid density, and mud displacement on the temperature field are analyzed. Besides these effects, the effect of temperature change on the stress around the borehole is analyzed based on thermoelasticity theory. In addition, the relationships between temperature and strength of four types of rocks are respectively established based on experimental results, and thermal expansion coefficients are also tested. On this basis, a borehole stability model is established considering thermal effects and the effect of temperature change on borehole stability is also analyzed. The results show that the fracture pressure and collapse pressure will both increase as the temperature of borehole rises, and vice versa. The fracture pressure is more sensitive to temperature. Temperature has different effects on collapse pressures due to different lithological characters; however, the variation of fracture pressure is unrelated to lithology. The research results can provide a reference for the design of drilling fluid density in high-temperature wells.

  10. Recrystallization of high temperature superconductors

    SciTech Connect

    Kouzoudis, D.

    1996-05-09

    Currently one of the most widely used high {Tc} superconductors is the Bi-based compounds Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub z} and Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub z} (known as BSCCO 2212 and 2223 compounds) with {Tc} values of about 85 K and 110 K respectively. Lengths of high performance conductors ranging from 100 to 1000 m long are routinely fabricated and some test magnets have been wound. An additional difficulty here is that although Bi-2212 and Bi-2223 phases exist over a wide range of stoichiometries, neither has been prepared in phase-pure form. So far the most successful method of constructing reliable and robust wires or tapes is the so called powder-in-tube (PIT) technique [1, 2, 3, 4, 5, 6, 7] in which oxide powder of the appropriate stoichiometry and phase content is placed inside a metal tube, deformed into the desired geometry (round wire or flat tape), and annealed to produce the desired superconducting properties. Intermediate anneals are often incorporated between successive deformation steps. Silver is the metal used in this process because it is the most compatible with the reacting phase. In all of the commercial processes for BSCCO, Ag seems to play a special catalytic role promoting the growth of high performance aligned grains that grow in the first few micrometers near the Ag/BSCCO interface. Adjacent to the Ag, the grain alignment is more perfect and the current density is higher than in the center of the tape. It is known that Ag lowers the melting point of several of the phases but the detailed mechanism for growth of these high performance grains is not clearly understood. The purpose of this work is to study the nucleation and growth of the high performance material at this interface.

  11. High temperature resistant cermet and ceramic compositions

    NASA Technical Reports Server (NTRS)

    Phillips, W. M. (Inventor)

    1978-01-01

    Cermet compositions having high temperature oxidation resistance, high hardness and high abrasion and wear resistance, and particularly adapted for production of high temperature resistant cermet insulator bodies are presented. The compositions are comprised of a sintered body of particles of a high temperature resistant metal or metal alloy, preferably molybdenum or tungsten particles, dispersed in and bonded to a solid solution formed of aluminum oxide and silicon nitride, and particularly a ternary solid solution formed of a mixture of aluminum oxide, silicon nitride and aluminum nitride. Also disclosed are novel ceramic compositions comprising a sintered solid solution of aluminum oxide, silicon nitride and aluminum nitride.

  12. Copper Alloy For High-Temperature Uses

    NASA Technical Reports Server (NTRS)

    Dreshfield, Robert L.; Ellis, David L.; Michal, Gary

    1994-01-01

    Alloy of Cu/8Cr/4Nb (numbers indicate parts by atom percent) improved over older high-temperature copper-based alloys in that it offers enhanced high temperature strength, resistance to creep, and ductility while retaining most of thermal conductivity of pure copper; in addition, alloy does not become embrittled upon exposure to hydrogen at temperatures as high as 705 degrees C. Designed for use in presence of high heat fluxes and active cooling; for example, in heat exchangers in advanced aircraft and spacecraft engines, and other high-temperature applications in which there is need for such material. High conductivity and hardness of alloy exploited in welding electrodes and in high-voltage and high-current switches and other applications in which wear poses design problem.

  13. Silicon carbide, a high temperature semiconductor

    NASA Technical Reports Server (NTRS)

    Powell, J. A.

    1983-01-01

    Electronic applications are described that would benefit from the availability of high temperature semiconductor devices. Comparisons are made among potential materials for these devices and the problems of each are discussed. Recent progress in developing silicon carbide as a high temperature semiconductor is described.

  14. Evaluation of high temperature polymers

    NASA Technical Reports Server (NTRS)

    Jayaraj, K.; Dorogy, W.; Farrell, B.; Landrau, N.

    1995-01-01

    The purpose of this paper is to identify and develop arc-track resistant insulation materials that can operate reliably at 300 C. In the first phase, high performance polymers are evaluated based on structure, thermal stability and electrical properties. Next, the polymers are ranked according to performance and experimental characterization. Then, experimental evaluations in wire configuration are conducted. And selection is made based on performance and commerical potential.

  15. High temperature superconductors for computer interconnect applications

    SciTech Connect

    Nilsson, B.J.L.

    1994-12-31

    High temperature superconductors, because of their extremely low loss at high frequencies and their high current handling capability, have the potential for use in computer interconnect boards. They offer the potential advantages of high interconnect density, reduced interconnect delays, and higher data rate. Because silicon CMOS circuits dramatically improve in performance at low temperatures, cooled computers may become attractive in the future to capture both the improved interconnect and circuit benefits.

  16. High-temperature Solar Cell Development

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Merritt, Danielle; Raffaelle, Ryne P.; Scheiman, David

    2005-01-01

    The vast majority of space probes to date have relied upon photovoltaic power generation. If future missions designed to probe environments close to the sun (Figure 1) will be able to use such power generation, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. The significant problem is that solar cells lose performance at high temperatures.

  17. High temperature solar selective coatings

    DOEpatents

    Kennedy, Cheryl E

    2014-11-25

    Improved solar collectors (40) comprising glass tubing (42) attached to bellows (44) by airtight seals (56) enclose solar absorber tubes (50) inside an annular evacuated space (54. The exterior surfaces of the solar absorber tubes (50) are coated with improved solar selective coatings {48} which provide higher absorbance, lower emittance and resistance to atmospheric oxidation at elevated temperatures. The coatings are multilayered structures comprising solar absorbent layers (26) applied to the meta surface of the absorber tubes (50), typically stainless steel, topped with antireflective Savers (28) comprising at least two layers 30, 32) of refractory metal or metalloid oxides (such as titania and silica) with substantially differing indices of refraction in adjacent layers. Optionally, at least one layer of a noble metal such as platinum can be included between some of the layers. The absorbent layers cars include cermet materials comprising particles of metal compounds is a matrix, which can contain oxides of refractory metals or metalloids such as silicon. Reflective layers within the coating layers can comprise refractory metal silicides and related compounds characterized by the formulas TiSi. Ti.sub.3SiC.sub.2, TiAlSi, TiAN and similar compounds for Zr and Hf. The titania can be characterized by the formulas TiO.sub.2, Ti.sub.3O.sub.5. TiOx or TiO.sub.xN.sub.1-x with x 0 to 1. The silica can be at least one of SiO.sub.2, SiO.sub.2x or SiO.sub.2xN.sub.1-x with x=0 to 1.

  18. Niche and neutral models predict asymptotically equivalent species abundance distributions in high-diversity ecological communities

    PubMed Central

    Chisholm, Ryan A.; Pacala, Stephen W.

    2010-01-01

    A fundamental challenge in ecology is to understand the mechanisms that govern patterns of relative species abundance. Previous numerical simulations have suggested that complex niche-structured models produce species abundance distributions (SADs) that are qualitatively similar to those of very simple neutral models that ignore differences between species. However, in the absence of an analytical treatment of niche models, one cannot tell whether the two classes of model produce the same patterns via similar or different mechanisms. We present an analytical proof that, in the limit as diversity becomes large, a strong niche model give rises to exactly the same asymptotic form of SAD as the neutral model, and we verify the analytical predictions for a Panamanian tropical forest data set. Our results strongly suggest that neutral processes drive patterns of relative species abundance in high-diversity ecological communities, even when strong niche structure exists. However, neutral theory cannot explain what generates high diversity in the first place, and it may not be valid in low-diversity communities. Our results also confirm that neutral theory cannot be used to infer an absence of niche structure or to explain ecosystem function. PMID:20733073

  19. Proteomic analysis of an unculturable bacterial endosymbiont (Blochmannia) reveals high abundance of chaperonins and biosynthetic enzymes

    PubMed Central

    Fan, Yongliang; Thompson, J. Will; Dubois, Laura G.; Moseley, M. Arthur; Wernegreen, Jennifer J.

    2013-01-01

    Many insect groups have coevolved with bacterial endosymbionts that live within specialized host cells. As a salient example, ants in the tribe Camponotini rely on Blochmannia, an intracellular bacterial mutualist that synthesizes amino acids and recycles nitrogen for the host. We performed a shotgun, label-free, LC/MS/MS quantitative proteomic analysis to investigate the proteome of Blochmannia associated with Camponotus chromaiodes. We identified more than 330 Blochmannia proteins, or 54% coverage of the predicted proteome, as well as 244 Camponotus proteins. Using the average intensity of the top 3 “best flier” peptides along with spiking of a surrogate standard at a known concentration, we estimated the concentration (fmol/μg) of those proteins with confident identification. The estimated dynamic range of Blochmannia protein abundance spanned three orders of magnitude and covered diverse functional categories, with particularly high representation of metabolism, information transfer, and chaperones. GroEL, the most abundant protein, totaled 6% of Blochmannia protein abundance. Biosynthesis of essential amino acids, fatty acids, and nucleotides, and sulfate assimilation had disproportionately high coverage in the proteome, further supporting a nutritional role of the symbiosis. This first quantitative proteomic analysis of an ant endosymbiont illustrates a promising approach to study the functional basis of intimate symbioses. PMID:23205679

  20. Widespread distribution and high abundance of Rhizobium radiobacter within Mediterranean subsurface sediments.

    PubMed

    Süss, Jacqueline; Schubert, Karin; Sass, Henrik; Cypionka, Heribert; Overmann, Jörg; Engelen, Bert

    2006-10-01

    Eastern Mediterranean sediments are characterized by the occurrence of distinct, organic-rich layers, called sapropels. These harbour elevated microbial numbers in comparison with adjacent carbon-lean intermediate layers. A recently obtained culture collection from these sediments was composed of 20% of strains closely related to Rhizobium radiobacter, formerly classified as Agrobacterium tumefaciens. To prove and quantify the in situ abundance of R. radiobacter, a highly specific quantitative polymerase chain reaction (PCR) protocol was developed. To convert quantification results into cell numbers, the copy number of rrn operons per genome was determined. Southern hybridization showed that our isolates contained four operons. Finally, quantitative PCR was applied to 45 sediment samples obtained across the eastern Mediterranean. Rhizobium radiobacter was present in 38 of 45 samples indicating an almost ubiquitous distribution. In total, 25-40 000 cells per gram of sediment were detected, corresponding to 0.001-5.1% of the bacterial cells. In general, the relative and absolute abundance of R. radiobacter increased with depth and was higher in sapropels than in intermediate layers. This indicates that R. radiobacter forms an active population in up to 200 000 years old sapropels. The present study shows for the first time that a cultivated subsurface bacterium is highly abundant in this environment.

  1. Evidence of nitrification and denitrification in high and low microbial abundance sponges.

    PubMed

    Schläppy, Marie-Lise; Schöttner, Sandra I; Lavik, Gaute; Kuypers, Marcel M M; de Beer, Dirk; Hoffmann, Friederike

    2010-01-01

    Aerobic and anaerobic microbial key processes were quantified and compared to microbial numbers and morphological structure in Mediterranean sponges. Direct counts on histological sections stained with DAPI showed that sponges with high microbial abundances (HMA sponges) have a denser morphological structure with a reduced aquiferous system compared to low microbial abundance (LMA) sponges. In Dysidea avara, the LMA sponge, rates of nitrification and denitrification were higher than in the HMA sponge Chondrosia reniformis, while anaerobic ammonium oxidation and sulfate reduction were below detection in both species. This study shows that LMA sponges may host physiologically similar microbes with comparable or even higher metabolic rates than HMA sponges, and that anaerobic processes such as denitrification can be found both in HMA and LMA sponges. A higher concentration of microorganisms in the mesohyl of HMA compared to LMA sponges may indicate a stronger retention of and, hence, a possible benefit from associated microbes.

  2. Structural characterization of high temperature composites

    NASA Technical Reports Server (NTRS)

    Mandell, J. F.; Grande, D. H.

    1991-01-01

    Glass, ceramic, and carbon matrix composite materials have emerged in recent years with potential properties and temperature resistance which make them attractive for high temperature applications such as gas turbine engines. At the outset of this study, only flexural tests were available to evaluate brittle matrix composites at temperatures in the 600 to 1000 C range. The results are described of an ongoing effort to develop appropriate tensile, compression, and shear test methods for high temperature use. A tensile test for unidirectional composites was developed and used to evaluate the properties and behavior of ceramic fiber reinforced glass and glass-ceramic matrix composites in air at temperatures up to 1000 C. The results indicate generally efficient fiber reinforcement and tolerance to matrix cracking similar to polymer matrix composites. Limiting properties in these materials may be an inherently very low transverse strain to failure, and high temperature embrittlement due to fiber/matrix interface oxidation.

  3. Influence of the vapor flux on temperature, density, and abundance distributions in a multicomponent, porous, icy body

    NASA Technical Reports Server (NTRS)

    Benkhoff, J.; Huebner, W. F.

    1995-01-01

    We calculated the vapor flux of the icy components in the surface layer of a porous, short-period, Jupiter-class comet, in order to investigate the relationship of the observed relative molecular abundances in the coma with those in the nucleus. The model assumes a body containing one major ice component (H20) and up to three minor components of higher volatility (e.g., CO, CO2, CH3OH). The body's porous structure is modeled as a bundle of tubes with a given tortuosity and initially a constant pore diameter. The mass and energy equations for the different volatiles are solved simultaneously under appropiate boundary conditions. Heat is conducted by the matrix and carried by the vapors. The one-dimensional model includes radially inward and outward flowing vapor within the body, complete depletion of less volatile ices in outer layers, and recondensation of vapor in deeper, coller layers. As a result, we obtain the temperature and abundance distribution in the nucleus and the gas flux into the interior and into the coma for each of the volatiles at various positions in the orbit. The ratio of the gas flux of minor volatiles to that of H2) in the coma varies by several orders of magnitude throughout the orbit. Thus, the relative abundances of species observed in the coma are in most cases not the same as those in the nucleus. Results also indicate that it will be impossible to determine the relative abundances of ices more volatile than water from samples taken a few meters below the surface during a comet rendezvous mission. We made calculations for a wide range of different parameters, such as porosity, pore radius, and thermal conductivity of the matrix. To introduce the model we present typical results for a dust-free comet.

  4. Chemical abundances in a high-velocity RR Lyrae star near the bulge

    NASA Astrophysics Data System (ADS)

    Hansen, C. J.; Rich, R. M.; Koch, A.; Xu, S.; Kunder, A.; Ludwig, H.-G.

    2016-05-01

    Low-mass variable high-velocity stars are interesting study cases for many aspects of Galactic structure and evolution. Until recently, the only known high- or hyper-velocity stars were young stars thought to originate from the Galactic center. Wide-area surveys such as APOGEE and BRAVA have found several low-mass stars in the bulge with Galactic rest-frame velocities higher than 350 km s-1. In this study we present the first abundance analysis of a low-mass RR Lyrae star that is located close to the Galactic bulge, with a space motion of ~-400 km s-1. Using medium-resolution spectra, we derived abundances (including upper limits) of 11 elements. These allowed us to chemically tag the star and discuss its origin, although our derived abundances and metallicity, at [Fe/H] =-0.9 dex, do not point toward one unambiguous answer. Based on the chemical tagging, we cannot exclude that it originated in the bulge. However, its retrograde orbit and the derived abundances combined suggest that the star was accelerated from the outskirts of the inner (or even outer) halo during many-body interactions. Other possible origins include the bulge itself, or the star might have been stripped from a stellar cluster or the Sagittarius dwarf galaxy when it merged with the Milky Way. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  5. Insects and low temperatures: from molecular biology to distributions and abundance.

    PubMed Central

    Bale, J S

    2002-01-01

    Insects are the most diverse fauna on earth, with different species occupying a range of terrestrial and aquatic habitats from the tropics to the poles. Species inhabiting extreme low-temperature environments must either tolerate or avoid freezing to survive. While much is now known about the synthesis, biochemistry and function of the main groups of cryoprotectants involved in the seasonal processes of acclimatization and winter cold hardiness (ice-nucleating agents, polyols and antifreeze proteins), studies on the structural biology of these compounds have been more limited. The recent discovery of rapid cold-hardening, ice-interface desiccation and the daily resetting of critical thermal thresholds affecting mortality and mobility have emphasized the role of temperature as the most important abiotic factor, acting through physiological processes to determine ecological outcomes. These relationships are seen in key areas such as species responses to climate warming, forecasting systems for pest outbreaks and the establishment potential of alien species in new environments. PMID:12171648

  6. A batteryless temperature sensor based on high temperature sensitive material

    NASA Astrophysics Data System (ADS)

    Bakkali, Asma; Pelegri-Sebastia, José; Laghmich, Youssef; Lyhyaoui, Abdelouahid

    2016-05-01

    The major challenge in wireless sensor networks is the reduction of energy consumption. Passive wireless sensor network is an attractive solution for measuring physical parameters in harsh environment for large range of applications requiring sensing devices with low cost of fabrication, small size and long term measurement stability. Batteryless temperature sensing techniques are an active research field. The approach developed in our work holds a promising future for temperature sensor applications in order to successfully reduce the energy consumption. The temperature sensor presented in this paper is based on the electromagnetic transduction principle using the integration of the high temperature sensitive material into a passive structure. Variation in temperature makes the dielectric constant of this material changing, and such modification induces variation in the resonant frequencies of high-Q whispering-gallery modes (WGM) in the millimeter-wave frequency range. Following the results achieved, the proposed device shows a linear response to the increasing temperature and these variations can be remotely detected from a radar interrogation. Contribution to the topical issue "Materials for Energy Harvesting, Conversion and Storage (ICOME 2015) - Elected submissions", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  7. Predicting abundance and variability of ice nucleating particles in precipitation at the high-altitude observatory Jungfraujoch

    NASA Astrophysics Data System (ADS)

    Stopelli, Emiliano; Conen, Franz; Morris, Cindy E.; Herrmann, Erik; Henne, Stephan; Steinbacher, Martin; Alewell, Christine

    2016-07-01

    Nucleation of ice affects the properties of clouds and the formation of precipitation. Quantitative data on how ice nucleating particles (INPs) determine the distribution, occurrence and intensity of precipitation are still scarce. INPs active at -8 °C (INPs-8) were observed for 2 years in precipitation samples at the High-Altitude Research Station Jungfraujoch (Switzerland) at 3580 m a.s.l. Several environmental parameters were scanned for their capability to predict the observed abundance and variability of INPs-8. Those singularly presenting the best correlations with observed number of INPs-8 (residual fraction of water vapour, wind speed, air temperature, number of particles with diameter larger than 0.5 µm, season, and source region of particles) were implemented as potential predictor variables in statistical multiple linear regression models. These models were calibrated with 84 precipitation samples collected during the first year of observations; their predictive power was successively validated on the set of 15 precipitation samples collected during the second year. The model performing best in calibration and validation explains more than 75 % of the whole variability of INPs-8 in precipitation and indicates that a high abundance of INPs-8 is to be expected whenever high wind speed coincides with air masses having experienced little or no precipitation prior to sampling. Such conditions occur during frontal passages, often accompanied by precipitation. Therefore, the circumstances when INPs-8 could be sufficiently abundant to initiate the ice phase in clouds may frequently coincide with meteorological conditions favourable to the onset of precipitation events.

  8. Change in gene abundance in the nitrogen biogeochemical cycle with temperature and nitrogen addition in Antarctic soils.

    PubMed

    Jung, Jaejoon; Yeom, Jinki; Kim, Jisun; Han, Jiwon; Lim, Hyoun Soo; Park, Hyun; Hyun, Seunghun; Park, Woojun

    2011-12-01

    The microbial community (bacterial, archaeal, and fungi) and eight genes involved in the nitrogen biogeochemical cycle (nifH, nitrogen fixation; bacterial and archaeal amoA, ammonia oxidation; narG, nitrate reduction; nirS, nirK, nitrite reduction; norB, nitric oxide reduction; and nosZ, nitrous oxide reduction) were quantitatively assessed in this study, via real-time PCR with DNA extracted from three Antarctic soils. Interestingly, AOB amoA was found to be more abundant than AOA amoA in Antarctic soils. The results of microcosm studies revealed that the fungal and archaeal communities were diminished in response to warming temperatures (10 °C) and that the archaeal community was less sensitive to nitrogen addition, which suggests that those two communities are well-adapted to colder temperatures. AOA amoA and norB genes were reduced with warming temperatures. The abundance of only the nifH and nirK genes increased with both warming and the addition of nitrogen. NirS-type denitrifying bacteria outnumbered NirK-type denitrifiers regardless of the treatment used. Interestingly, dramatic increases in both NirS and NirK-types denitrifiers were observed with nitrogen addition. NirK types increase with warming, but NirS-type denitrifiers tend to be less sensitive to warming. Our findings indicated that the Antarctic microbial nitrogen cycle could be dramatically altered by temperature and nitrogen, and that warming may be detrimental to the ammonia-oxidizing archaeal community. To the best of our knowledge, this is the first report to investigate genes associated with each process of the nitrogen biogeochemical cycle in an Antarctic terrestrial soil environment.

  9. Compositional evolution of high-temperature sheared lherzolite PHN 1611

    SciTech Connect

    Smith, D. ); Griffin, W.L.; Ryan, C.G. )

    1993-02-01

    The evolution of fertile' mantle has been studied by proton microprobe (PIXE) analysis of minerals of a high-temperature sheared xenolith from the Thaba Putsoa kimerlite in Lesotho, southern Africa. Analyzed elements include Ni, Cu, Zn, Ga, Sr, Y, and Zr. Garnets are homogeneous in Ni and Zn but have rims enriched relative to cores in Zr and Y. Compositions of olivine neoblasts define intergranular gradients of Fe, Zn, and Ni; Fe-rich olivine is relatively Zn-rich but Ni-poore. Although individual clinopyroxene grains are nearly homogeneous, clinopyroxene associated with Fe-rich olivine is relatively Fe- and Zn-rich but Sr- and Cr-poor. The trace-element abundances and compositional gradients constrain the processes of periodotite enrichment and the thermal history. Enrichment of Zr, Y, and Fe in garnet rims documents infiltration of a silica-undersaturated melt. The Fe-rich olivine compositions and the Zn and Fe gradients establish that the xenolith was sampled from near a melt conduit. Mechanical mixing of inhomogeneous peridotite and melt infiltration may have been concurrent. Because garnets appear homogeneous in Ni, mantle temperature changes affecting PHN 1611 occurred before or over a longer period than the melt infiltration. Measured and calculated abundances of many incompatible trace elements in the rock are similar to those proposed for primitive mantle. Calculated chondrite-normalized abundances of Sr, Ti, Zr, and Y are like those of appropriate REE. Enrichment processes in PHN 1611 proceeded at unusually high recorded temperature and in the apparent absence of minor phases common in lower-temperature metasomatized rocks, but similar processes may be common. In particular, mechanical mixing near mantle dikes may frequently occur. These enrichment mechanisms may produce xenolith compositions that resemble some proposed for primitive mantle but that have different implications for mantle evolution. 61 refs., 7 figs., 2 tabs.

  10. GeoChip-based insights into the microbial functional gene repertoire of marine sponges (high microbial abundance, low microbial abundance) and seawater.

    PubMed

    Bayer, Kristina; Moitinho-Silva, Lucas; Brümmer, Franz; Cannistraci, Carlo V; Ravasi, Timothy; Hentschel, Ute

    2014-12-01

    The GeoChip 4.2 gene array was employed to interrogate the microbial functional gene repertoire of sponges and seawater collected from the Red Sea and the Mediterranean. Complementary amplicon sequencing confirmed the microbial community composition characteristic of high microbial abundance (HMA) and low microbial abundance (LMA) sponges. By use of GeoChip, altogether 20,273 probes encoding for 627 functional genes and representing 16 gene categories were identified. Minimum curvilinear embedding analyses revealed a clear separation between the samples. The HMA/LMA dichotomy was stronger than any possible geographic pattern, which is shown here for the first time on the level of functional genes. However, upon inspection of individual genes, very few specific differences were discernible. Differences were related to microbial ammonia oxidation, ammonification, and archaeal autotrophic carbon fixation (higher gene abundance in sponges over seawater) as well as denitrification and radiation-stress-related genes (lower gene abundance in sponges over seawater). Except for few documented specific differences the functional gene repertoire between the different sources appeared largely similar. This study expands previous reports in that functional gene convergence is not only reported between HMA and LMA sponges but also between sponges and seawater.

  11. Sandia_HighTemperatureComponentEvaluation_2015.

    SciTech Connect

    Cashion, Avery T.

    2015-03-01

    The objective of this project is to perform independent evaluation of high temperature components to determine their suitability for use in high temperature geothermal tools. Development of high temperature components has been increasing rapidly due to demand from the high temperature oil and gas exploration and aerospace industries. Many of these new components are at the late prototype or first production stage of development and could benefit from third party evaluation of functionality and lifetime at elevated temperatures. In addition to independent testing of new components, this project recognizes that there is a paucity of commercial-off-the-shelf COTS components rated for geothermal temperatures. As such, high-temperature circuit designers often must dedicate considerable time and resources to determine if a component exists that they may be able to knead performance out of to meet their requirements. This project aids tool developers by characterization of select COTS component performances beyond published temperature specifications. The process for selecting components includes public announcements of project intent (e.g., FedBizOps), direct discussions with candidate manufacturers,and coordination with other DOE funded programs.

  12. Water abundance variations around high-mass protostars: HIFI observations of the DR21 region

    NASA Astrophysics Data System (ADS)

    van der Tak, F. F. S.; Marseille, M. G.; Herpin, F.; Wyrowski, F.; Baudry, A.; Bontemps, S.; Braine, J.; Doty, S.; Frieswijk, W.; Melnick, G.; Shipman, R.; van Dishoeck, E. F.; Benz, A. O.; Caselli, P.; Hogerheijde, M.; Johnstone, D.; Liseau, R.; Bachiller, R.; Benedettini, M.; Bergin, E.; Bjerkeli, P.; Blake, G.; Bruderer, S.; Cernicharo, J.; Codella, C.; Daniel, F.; di Giorgio, A. M.; Dominik, C.; Encrenaz, P.; Fich, M.; Fuente, A.; Giannini, T.; Goicoechea, J.; de Graauw, Th.; Helmich, F.; Herczeg, G.; Jørgensen, J.; Kristensen, L.; Larsson, B.; Lis, D.; McCoey, C.; Neufeld, D.; Nisini, B.; Olberg, M.; Parise, B.; Pearson, J.; Plume, R.; Risacher, C.; Santiago, J.; Saraceno, P.; Tafalla, M.; van Kempen, T.; Visser, R.; Wampfler, S.; Yıldız, U.; Ravera, L.; Roelfsema, P.; Siebertz, O.; Teyssier, D.

    2010-07-01

    Context. Water is a key molecule in the star formation process, but its spatial distribution in star-forming regions is not well known. Aims: We study the distribution of dust continuum and H2O and 13CO line emission in DR21, a luminous star-forming region with a powerful outflow and a compact H ii region. Methods: Herschel-HIFI spectra near 1100 GHz show narrow 13CO 10-9 emission and H2O 111-000 absorption from the dense core and broad emission from the outflow in both lines. The H2O line also shows absorption by a foreground cloud known from ground-based observations of low-J CO lines. Results: The dust continuum emission is extended over 36” FWHM, while the 13CO and H2O lines are confined to ≈24” or less. The foreground absorption appears to peak further North than the other components. Radiative transfer models indicate very low abundances of ~2×10-10 for H2O and ~8×10-7 for 13CO in the dense core, and higher H2O abundances of ~4×10-9 in the foreground cloud and ~7×10-7 in the outflow. Conclusions: The high H2O abundance in the warm outflow is probably due to the evaporation of water-rich icy grain mantles, while the H2O abundance is kept down by freeze-out in the dense core and by photodissociation in the foreground cloud. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  13. Low to high temperature energy conversion system

    NASA Technical Reports Server (NTRS)

    Miller, C. G. (Inventor)

    1977-01-01

    A method for converting heat energy from low temperature heat sources to higher temperature was developed. It consists of a decomposition chamber in which ammonia is decomposed into hydrogen and nitrogen by absorbing heat of decomposition from a low temperature energy source. A recombination reaction then takes place which increases the temperature of a fluid significantly. The system is of use for the efficient operation of compact or low capital investment turbine driven electrical generators, or in other applications, to enable chemical reactions that have a critical lower temperature to be used. The system also recovers heat energy from low temperature heat sources, such as solar collectors or geothermal sources, and converts it to high temperatures.

  14. Silicon Carbide Nanotube Oxidation at High Temperatures

    NASA Technical Reports Server (NTRS)

    Ahlborg, Nadia; Zhu, Dongming

    2012-01-01

    Silicon Carbide Nanotubes (SiCNTs) have high mechanical strength and also have many potential functional applications. In this study, SiCNTs were investigated for use in strengthening high temperature silicate and oxide materials for high performance ceramic nanocomposites and environmental barrier coating bond coats. The high · temperature oxidation behavior of the nanotubes was of particular interest. The SiCNTs were synthesized by a direct reactive conversion process of multiwall carbon nanotubes and silicon at high temperature. Thermogravimetric analysis (TGA) was used to study the oxidation kinetics of SiCNTs at temperatures ranging from 800degC to1300degC. The specific oxidation mechanisms were also investigated.

  15. Aeronautical applications of high-temperature superconductors

    NASA Technical Reports Server (NTRS)

    Turney, George E.; Luidens, Roger W.; Uherka, Kenneth; Hull, John

    1989-01-01

    The successful development of high-temperature superconductors (HTS) could have a major impact on future aeronautical propulsion and aeronautical flight vehicle systems. A preliminary examination of the potential application of HTS for aeronautics indicates that significant benefits may be realized through the development and implementation of these newly discovered materials. Applications of high-temperature superconductors (currently substantiated at 95 K) were envisioned for several classes of aeronautical systems, including subsonic and supersonic transports, hypersonic aircraft, V/STOL aircraft, rotorcraft, and solar, microwave and laser powered aircraft. Introduced and described are the particular applications and potential benefits of high-temperature superconductors as related to aeronautics and/or aeronautical systems.

  16. Symposium on high temperature and materials chemistry

    SciTech Connect

    Not Available

    1989-10-01

    This volume contains the written proceedings of the Symposium on High Temperature and Materials Chemistry held in Berkeley, California on October 24--25, 1989. The Symposium was sponsored by the Materials and Chemical Sciences Division of Lawrence Berkeley Laboratory and by the College of Chemistry of the University of California at Berkeley to discuss directions, trends, and accomplishments in the field of high temperature and materials chemistry. Its purpose was to provide a snapshot of high temperature and materials chemistry and, in so doing, to define status and directions.

  17. The high temperature superconductivity space experiment

    NASA Technical Reports Server (NTRS)

    Webb, Denis C.; Nisenoff, M.

    1991-01-01

    The history and the current status of the high temperature superconductivity space experiment (HTSSE) initiated in 1988 are briefly reviewed. The goal of the HTSSE program is to demonstrate the feasibility of incorporating high temperature superconductivity (HTS) technology into space systems. The anticipated payoffs include the development of high temperature superconductor devices for space systems; preparation and space qualification of a cryogenically cooled experimental package containing HTS devices and components; and acquisition of data for future space experiments using more complex HTS devices and subsystems. The principal HTSSE systems and devices are described.

  18. Dimensionality of high temperature superconductivity in oxides

    NASA Technical Reports Server (NTRS)

    Chu, C. W.

    1989-01-01

    Many models have been proposed to account for the high temperature superconductivity observed in oxide systems. Almost all of these models proposed are based on the uncoupled low dimensional carrier Cu-O layers of the oxides. Results of several experiments are presented and discussed. They suggest that the high temperature superconductivity observed cannot be strictly two- or one-dimensional, and that the environment between the Cu-O layers and the interlayer coupling play an important role in the occurrence of such high temperature superconductivity. A comment on the very short coherence length reported is also made.

  19. A high-temperature wideband pressure transducer

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J.

    1975-01-01

    Progress in the development of a pressure transducer for measurement of the pressure fluctuations in the high temperature environment of a jet exhaust is reported. A condenser microphone carrier system was adapted to meet the specifications. A theoretical analysis is presented which describes the operation of the condenser microphone in terms of geometry, materials, and other physical properties. The analysis was used as the basis for design of a prototype high temperature microphone. The feasibility of connecting the microphone to a converter over a high temperature cable operating as a half-wavelength transmission line was also examined.

  20. High temperature solid state storage cell

    DOEpatents

    Rea, Jesse R.; Kallianidis, Milton; Kelsey, G. Stephen

    1983-01-01

    A completely solid state high temperature storage cell comprised of a solid rechargeable cathode such as TiS.sub.2, a solid electrolyte which remains solid at the high temperature operating conditions of the cell and which exhibits high ionic conductivity at such elevated temperatures such as an electrolyte comprised of lithium iodide, and a solid lithium or other alkali metal alloy anode (such as a lithium-silicon alloy) with 5-50% by weight of said anode being comprised of said solid electrolyte.

  1. High Temperature Thermographic Phosphor Coatings Development

    NASA Technical Reports Server (NTRS)

    Goedeke, Shawn; Allison, S. W.; Beshears, D. L.; Bencic, T.; Cates, M. R.; Hollerman, W. A.; Guidry, R.

    2003-01-01

    For many years, phosphor thermometry has been used for non-contact temperature measurements. A large number of applications have been associated with high temperatures, especially for aerospace systems where blackbody radiation backgrounds are large and in challenging environments, such as vibration, rotation, flame, or noise. These environments restrict the use of more common thermocouples or infrared thermometric techniques. In particular, temperature measurements inside jet turbines, rocket engines, or similar devices are especially amenable to phosphor techniques. Often the fluorescent materials are used as powders, either suspended in binders and applied like paint or applied as high-temperature sprays. Thin coatings that are less than 50 m thick are used on the surfaces of interest. These coatings will quickly assume the same temperature as the surface to which they are applied. The temperature dependence of fluorescent materials is a function of the base matrix atoms and a small quantity of added activator or dopant ions. Often for high temperature applications, the selected materials are refractory and include rare earth ions. Phosphors like Y3Al5O12 (YAG) doped with Eu, Dy, or Tm, Y2O3 doped with Eu, or similar rare earth compounds, will survive high temperatures and can be configured to emit light that changes rapidly in lifetime and intensity. For example, researchers at Oak Ridge National Laboratory recently observed fluorescence from YAG:Dy and YAG:Tm at temperatures above 1400 C. One of the biggest challenges is to locate a binder material that can withstand tremendous variations in temperature in an adverse aerospace environment. This poster will provide an overview into our attempt to utilize phosphors for thermometry purposes. Emphasis will be placed on the use of selected binder materials that can withstand high temperatures. This research was completed for the National Aeronautics and Space Administration's Glenn Research Center in Cleveland

  2. High temperature acclimation through PIF4 signaling.

    PubMed

    Proveniers, Marcel C G; van Zanten, Martijn

    2013-02-01

    Ambient temperature has direct consequences for plant functioning. Many plant species are able to adjust reproductive timing and development to optimize fitness to changes in ambient temperatures. Understanding the molecular networks of how plants cope with high temperatures is essential to counteract the effects of global warming and to secure future crop productivity. Several recent papers reported that Arabidopsis thaliana responses to changing light conditions and high temperature, and their underlying signaling mechanisms are highly similar and involve the basic helix-loop-helix (bHLH) transcription factor PHYTOCHROME INTERACTING FACTOR 4 (PIF4). In this opinion article we discuss the mechanisms of PIF4-mediated acclimation to increased ambient temperature with focus on timing of flowering and morphological acclimation.

  3. High temperature erosion of nickel alloys

    SciTech Connect

    Zhou, J.

    1995-12-31

    High temperature erosion behavior was studied on three commercial nickel alloys, Inconel 718, Inconel 601 and Inconel X-750, using a vertical sand-blast type of erosion test rig. Effect of temperature on erosion was investigated by varying test temperature in six steps from ambient up to 800 C. Other erosion variables investigated included impingement angle, changed from 10{degree} to 90{degree}, and impingement velocity, covered a range of 40 to 90 m/s. Extensive studies on erosion surface morphological features were done on eroded or eroded-corroded specimen surfaces using scanning electron microscopy. Thermogravimetric analysis and scratch test revealed corrosion rate, characteristics of oxide scale formed at high temperature, and some effects of corrosion on erosion. It was found that variation of erosion rate with temperature was directly related to temperature-dependent mechanical property changes of the materials. The mechanisms of the high-temperature erosion were analyzed based on test results. It was observed that erosion was dominant in temperature range up to 800 C, while corrosion played increased roles in upper portion of the temperature range tested.

  4. High temperature thermometric phosphors for use in a temperature sensor

    DOEpatents

    Allison, Stephen W.; Cates, Michael R.; Boatner, Lynn A.; Gillies, George T.

    1998-01-01

    A high temperature phosphor consists essentially of a material having the general formula LuPO.sub.4 :Dy.sub.(x),Eu.sub.(y), wherein: 0.1 wt %.ltoreq.x.ltoreq.20 wt % and 0.1 wt %.ltoreq.y.ltoreq.20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopent. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions.

  5. High temperature thermometric phosphors for use in a temperature sensor

    DOEpatents

    Allison, S.W.; Cates, M.R.; Boatner, L.A.; Gillies, G.T.

    1998-03-24

    A high temperature phosphor consists essentially of a material having the general formula LuPO{sub 4}:Dy{sub (x)},Eu{sub (y)}, wherein: 0.1 wt %{<=}x{<=}20 wt % and 0.1 wt %{<=}y{<=}20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopant. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions. 2 figs.

  6. Electrical Properties Of Capacitors At High Temperatures

    NASA Technical Reports Server (NTRS)

    Baumann, E. D.; Myers, I. T.; Overton, E.; Hammoud, A. N.

    1994-01-01

    Brief report describes results of experiments in which capacitance and dielectric loss of glass, metallized-polytetrafluoroethylene, and solid-tantalum capacitor measured at temperatures from 20 degrees C to 200 degrees C. Conclusions drawn concerning suitability of capacitors for use at high temperatures; such as in nuclear powerplants, aircraft, equipment for extracting geothermal energy, switching power supplies, and automotive integrated engine electronics.

  7. High temperature ceramic/metal joint structure

    DOEpatents

    Boyd, Gary L.

    1991-01-01

    A high temperature turbine engine includes a hybrid ceramic/metallic rotor member having ceramic/metal joint structure. The disclosed joint is able to endure higher temperatures than previously possible, and aids in controlling heat transfer in the rotor member.

  8. High temperature superconductor materials and applications

    NASA Technical Reports Server (NTRS)

    Doane, George B., III.; Banks, Curtis; Golben, John

    1990-01-01

    Research on processing methods leading to a significant enhancement in the critical current densities (Jc) and the critical temperature (Tc) of high temperature superconducting in thin bulk and thin film forms. The fabrication of important devices for NASA unique applications (sensors) is investigated.

  9. Assigning thermodynamic temperatures to high-temperature fixed-points

    NASA Astrophysics Data System (ADS)

    Woolliams, E. R.; Bloembergen, P.; Machin, G.

    2013-09-01

    Workpackage five of the High Temperature Fixed-Point research programme will determine the thermodynamic temperature for the equilibrium melting transition of the pure eutectic systems of Re-C, Pt-C and Co-C and, in addition, the freezing point of Cu. Measurements of four different cells of each type will be made by nine participating laboratories. This paper describes how the melt sensitivity to the rate of the previous freeze, furnace effects and cell impurities will be accounted for and how the results will be combined allowing for all existing correlations.

  10. High-Temperature Optical Window Design

    NASA Technical Reports Server (NTRS)

    Roeloffs, Norman; Taranto, Nick

    1995-01-01

    A high-temperature optical window is essential to the optical diagnostics of high-temperature combustion rigs. Laser Doppler velocimetry, schlieren photography, light sheet visualization, and laser-induced fluorescence spectroscopy are a few of the tests that require optically clear access to the combustor flow stream. A design was developed for a high-temperature window that could withstand the severe environment of the NASA Lewis 3200 F Lean Premixed Prevaporized (LPP) Flame Tube Test Rig. The development of this design was both time consuming and costly. This report documents the design process and the lessons learned, in an effort to reduce the cost of developing future designs for high-temperature optical windows.

  11. A sharp knife for high temperatures

    NASA Technical Reports Server (NTRS)

    Heisman, R. M.; Iceland, W. F.

    1978-01-01

    Electrically heated nickel-chrome-steel alloy knife may be used to cut heat resistant plastic felt and similar materials with relative ease. Blade made of commercially available alloy RA 330 retains edge at temperatures as high as 927 C.

  12. Measuring Moduli Of Elasticity At High Temperatures

    NASA Technical Reports Server (NTRS)

    Wolfenden, Alan

    1993-01-01

    Shorter, squatter specimens and higher frequencies used in ultrasonic measurement technique. Improved version of piezo-electric ultrasonic composite oscillator technique used to measure moduli of elasticity of solid materials at high temperatures.

  13. Silicon carbide, an emerging high temperature semiconductor

    NASA Technical Reports Server (NTRS)

    Matus, Lawrence G.; Powell, J. Anthony

    1991-01-01

    In recent years, the aerospace propulsion and space power communities have expressed a growing need for electronic devices that are capable of sustained high temperature operation. Applications for high temperature electronic devices include development instrumentation within engines, engine control, and condition monitoring systems, and power conditioning and control systems for space platforms and satellites. Other earth-based applications include deep-well drilling instrumentation, nuclear reactor instrumentation and control, and automotive sensors. To meet the needs of these applications, the High Temperature Electronics Program at the Lewis Research Center is developing silicon carbide (SiC) as a high temperature semiconductor material. Research is focussed on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of silicon carbide electronic devices and integrated sensors. The progress made in developing silicon carbide is presented, and the challenges that lie ahead are discussed.

  14. High-temperature superconductivity: A conventional conundrum

    DOE PAGES

    Božović, Ivan

    2016-01-07

    High-temperature superconductivity in ultrathin films of iron selenide deposited on strontium titanate has been attributed to various exotic mechanisms, and new experiments indicate that it may be conventional, with broader implications.

  15. The Conference on High Temperature Electronics

    NASA Technical Reports Server (NTRS)

    Hamilton, D. J.; Mccormick, J. B.; Kerwin, W. J.; Narud, J. A.

    1981-01-01

    The status of and directions for high temperature electronics research and development were evaluated. Major objectives were to (1) identify common user needs; (2) put into perspective the directions for future work; and (3) address the problem of bringing to practical fruition the results of these efforts. More than half of the presentations dealt with materials and devices, rather than circuits and systems. Conference session titles and an example of a paper presented in each session are (1) User requirements: High temperature electronics applications in space explorations; (2) Devices: Passive components for high temperature operation; (3) Circuits and systems: Process characteristics and design methods for a 300 degree QUAD or AMP; and (4) Packaging: Presently available energy supply for high temperature environment.

  16. Altering high temperature subterranean formation permeability

    SciTech Connect

    Moradi-Araghi, A.

    1991-02-19

    This patent describes a delayed acrylamide containing polymer crosslinker having stability in an aqueous solution at high temperatures. It comprises: a combination of an aldehyde and a salicylic acid derivative selected from salicylamide and acetysalicylic acid.

  17. Materials for high-temperature thermoelectric conversion

    NASA Technical Reports Server (NTRS)

    Feigelson, R. S.; Elwell, D.; Auld, B. A.

    1984-01-01

    The development of materials for high temperature thermoelectric energy conversion devices was investigated. The development of new criteria for the selection of materials which is based on understanding of the fundamental principles governing the behavior of high temperature thermoelectric materials is discussed. The synthesis and characterization of promising new materials and the growth of single crystals to eliminate possible problems associated with grain boundaries and other defects in polycrystalline materials are outlined.

  18. PLA recycling by hydrolysis at high temperature

    NASA Astrophysics Data System (ADS)

    Cristina, Annesini Maria; Rosaria, Augelletti; Sara, Frattari; Fausto, Gironi

    2016-05-01

    In this work the process of PLA hydrolysis at high temperature was studied, in order to evaluate the possibility of chemical recycling of this polymer bio-based. In particular, the possibility to obtain the monomer of lactic acid from PLA degradation was investigated. The results of some preliminary tests, performed in a laboratory batch reactor at high temperature, are presented: the experimental results show that the complete degradation of PLA can be obtained in relatively low reaction times.

  19. Recent developments in high temperature organic polymers

    NASA Technical Reports Server (NTRS)

    Hergenrother, P. M.

    1991-01-01

    Developments in high temperature organic polymers during the last 5 years with major emphasis on polyimides and poly(arylene ether)s are discussed. Specific polymers or series of polymers have been selected to demonstrate unique properties or the effect chemical structure has upon certain properties. This article is not intended to be a comprehensive review of high temperature polymer advancements during the last 5 years.

  20. High temperature structural fibers: Status and needs

    NASA Technical Reports Server (NTRS)

    Dicarlo, James A.

    1991-01-01

    The key to high temperature structural composites is the selection and incorporation of continuous fiber reinforcement with optimum mechanical, physical, and chemical properties. Critical fiber property needs are high strength, high stiffness, and retention of these properties during composite fabrication and use. However, unlike polymeric composites where all three requirements are easily achieved with a variety of commercially available carbon-based fibers, structural fibers with sufficient stiffness and strength retention for high temperature metal, intermetallic, and ceramic composites are not available. The objective here is to discuss in a general manner the thermomechanical stability problem for current high performance fibers which are based on silicon and alumina compositions. This is accomplished by presenting relevant fiber property data with a brief discussion of potential underlying mechanisms. From this general overview, some possible materials engineering approaches are suggested which may lead to minimization and/or elimination of this critical stability problem for current high temperature fibers.

  1. Apparatus and method for high temperature viscosity and temperature measurements

    DOEpatents

    Balasubramaniam, Krishnan; Shah, Vimal; Costley, R. Daniel; Singh, Jagdish P.

    2001-01-01

    A probe for measuring the viscosity and/or temperature of high temperature liquids, such as molten metals, glass and similar materials comprises a rod which is an acoustical waveguide through which a transducer emits an ultrasonic signal through one end of the probe, and which is reflected from (a) a notch or slit or an interface between two materials of the probe and (b) from the other end of the probe which is in contact with the hot liquid or hot melt, and is detected by the same transducer at the signal emission end. To avoid the harmful effects of introducing a thermally conductive heat sink into the melt, the probe is made of relatively thermally insulative (non-heat-conductive) refractory material. The time between signal emission and reflection, and the amplitude of reflections, are compared against calibration curves to obtain temperature and viscosity values.

  2. Quasipermanent magnets of high temperature superconductor - Temperature dependence

    NASA Technical Reports Server (NTRS)

    Chen, In-Gann; Liu, Jianxiong; Ren, Yanru; Weinstein, Roy; Kozlowski, Gregory; Oberly, Charles E.

    1993-01-01

    We report on persistent field in quasi-permanent magnets of high temperature superconductors. Magnets composed of irradiated Y(1+)Ba2Cu3O7 trapped field Bt = 1.52 T at 77 K and 1.9 T at lower temperature. However, the activation magnet limited Bt at lower temperature. We present data on Jc(H,T) for unirradiated materials, and calculate Bt at various T. Based upon data at 65 K, we calculate Bt in unirradiated single grains at 20 K and find that 5.2 T will be trapped for grain diameter d about 1.2 cm, and 7.9 T for d = 2.3 cm. Irradiated grains will trap four times these values.

  3. High-resolution mapping of elemental abundances of the lunar regolith

    NASA Astrophysics Data System (ADS)

    Wöhler, Christian; Berezhnoy, Alexey; Evans, Richard

    Many attempts have been made to derive elemental abundances of the lunar surface from mul-tispectral images (cf. e.g. [1]). The gamma ray spectrometer on board the Lunar Prospector spacecraft (LP GRS) provided the first "direct" global measurements of lunar elemental abun-dances including Fe, Th (15 km surface resolution), Ti, K, Sm (60 km), Al, O, Si, Mg, Ca, and U (150 km). In this study we rely on the elemental abundance estimation method intro-duced in [2], which is based on spectral features derived from the Clementine UVVIS+NIR data set and estimates the abundances of Ca, Al, Fe, Mg, Ti, and O by applying a second order polynomial regression model with the corresponding LP GRS abundances as "ground truth". The regarded spectral features are the continuum slope, the FWHM of the ferrous absorption trough near 1000 nm after continuum division, and the absorption wavelengths and relative absorption depths (cf. [2,3] for details). A petrographic analysis is performed based on the abundances of the key elements Al, Fe, and Mg [4]. The relative abundances of the endmem-bers mare basalt, Mg-rich rock, and ferroan anorthosite are estimated using Fe-Mg and Al-Mg diagrams, where the endmember compositions are determined based on the three-endmember plane fitted in Al-Fe-Mg space to the elemental abundances at 150 km resolution obtained with the regression model. The root-mean-square deviation from the three-endmember plane is only 0.3 wt percent. Our petrographic map shows Mg-rich rocks in the Mare Frigoris region, on the edges of large maria, in the South Pole Aitken basin, and in some cryptomaria such as the Schiller-Schickard basin. The presence of Mg-rich rocks in Mare Frigoris explains the Fe and Ti depletion discussed in [5]. Furthermore, our analysis confirms that the basalts of eastern mare Frigoris have an atypically high Al content [6]. The region south of Lichtenberg and around Seleucus and Briggs in northwestern Oceanus Procellarum is characterised by

  4. Ionization of NO at high temperature

    NASA Technical Reports Server (NTRS)

    Hansen, C. Frederick

    1991-01-01

    Space vehicles flying through the atmosphere at high speed are known to excite a complex set of chemical reactions in the atmospheric gases, ranging from simple vibrational excitation to dissociation, atom exchange, electronic excitation, ionization, and charge exchange. Simple arguments are developed for the temperature dependence of the reactions leading to ionization of NO, including the effect of vibrational electronic thermal nonequilibrium. NO ionization is the most important source of electrons at intermediate temperatures and at higher temperatures provides the trigger electrons that ionize atoms. Based on these arguments, recommendations are made for formulae which fit observed experimental results, and which include a dependence on both a heavy particle temperature and different vibration electron temperatures. In addition, these expressions will presumably provide the most reliable extrapolation of experimental results to much higher temperatures.

  5. High temperature crystalline superconductors from crystallized glasses

    DOEpatents

    Shi, Donglu

    1992-01-01

    A method of preparing a high temperature superconductor from an amorphous phase. The method involves preparing a starting material of a composition of Bi.sub.2 Sr.sub.2 Ca.sub.3 Cu.sub.4 Ox or Bi.sub.2 Sr.sub.2 Ca.sub.4 Cu.sub.5 Ox, forming an amorphous phase of the composition and heat treating the amorphous phase for particular time and temperature ranges to achieve a single phase high temperature superconductor.

  6. CpLEA5, the Late Embryogenesis Abundant Protein Gene from Chimonanthus praecox, Possesses Low Temperature and Osmotic Resistances in Prokaryote and Eukaryotes

    PubMed Central

    Liu, Yiling; Xie, Lixia; Liang, Xilong; Zhang, Shihong

    2015-01-01

    Plants synthesize and accumulate a series of stress-resistance proteins to protect normal physiological activities under adverse conditions. Chimonanthus praecox which blooms in freezing weather accumulates late embryogenesis abundant proteins (LEAs) in flowers, but C. praecox LEAs are little reported. Here, we report a group of five LEA genes of C. praecox (CpLEA5, KT727031). Prokaryotic-expressed CpLEA5 was employed in Escherichia coli to investigate bioactivities and membrane permeability at low-temperature. In comparison with the vacant strains, CpLEA5-containing strains survived in a 20% higher rate; and the degree of cell membrane damage in CpLEA5-containing strains was 55% of that of the vacant strains according to a conductivity test, revealing the low-temperature resistance of CpLEA5 in bacteria. CpLEA5 was also expressed in Pichia pastoris. Interestingly, besides low-temperature resistance, CpLEA5 conferred high resistance to salt and alkali in CpLEA5 overexpressing yeast. The CpLEA5 gene was transferred into Arabidopsis thaliana to also demonstrate CpLEA5 actions in plants. As expected, the transgenic lines were more resistant against low-temperature and drought while compared with the wild type. Taken together, CpLEA5-conferred resistances to several conditions in prokaryote and eukaryotes could have great value as a genetic technology to enhance osmotic stress and low-temperature tolerance. PMID:26569231

  7. CpLEA5, the Late Embryogenesis Abundant Protein Gene from Chimonanthus praecox, Possesses Low Temperature and Osmotic Resistances in Prokaryote and Eukaryotes.

    PubMed

    Liu, Yiling; Xie, Lixia; Liang, Xilong; Zhang, Shihong

    2015-01-01

    Plants synthesize and accumulate a series of stress-resistance proteins to protect normal physiological activities under adverse conditions. Chimonanthus praecox which blooms in freezing weather accumulates late embryogenesis abundant proteins (LEAs) in flowers, but C. praecox LEAs are little reported. Here, we report a group of five LEA genes of C. praecox (CpLEA5, KT727031). Prokaryotic-expressed CpLEA5 was employed in Escherichia coli to investigate bioactivities and membrane permeability at low-temperature. In comparison with the vacant strains, CpLEA5-containing strains survived in a 20% higher rate; and the degree of cell membrane damage in CpLEA5-containing strains was 55% of that of the vacant strains according to a conductivity test, revealing the low-temperature resistance of CpLEA5 in bacteria. CpLEA5 was also expressed in Pichia pastoris. Interestingly, besides low-temperature resistance, CpLEA5 conferred high resistance to salt and alkali in CpLEA5 overexpressing yeast. The CpLEA5 gene was transferred into Arabidopsis thaliana to also demonstrate CpLEA5 actions in plants. As expected, the transgenic lines were more resistant against low-temperature and drought while compared with the wild type. Taken together, CpLEA5-conferred resistances to several conditions in prokaryote and eukaryotes could have great value as a genetic technology to enhance osmotic stress and low-temperature tolerance. PMID:26569231

  8. Natural-abundance solid-state 2H NMR spectroscopy at high magnetic field.

    PubMed

    Aliev, Abil E; Mann, Sam E; Iuga, Dinu; Hughes, Colan E; Harris, Kenneth D M

    2011-06-01

    High-resolution solid-state (2)H NMR spectroscopy provides a method for measuring (1)H NMR chemical shifts in solids and is advantageous over the direct measurement of high-resolution solid-state (1)H NMR spectra, as it requires only the application of routine magic angle sample spinning (MAS) and routine (1)H decoupling methods, in contrast to the requirement for complex pulse sequences for homonuclear (1)H decoupling and ultrafast MAS in the case of high-resolution solid-state (1)H NMR. However, a significant obstacle to the routine application of high-resolution solid-state (2)H NMR is the very low natural abundance of (2)H, with the consequent problem of inherently low sensitivity. Here, we explore the feasibility of measuring (2)H MAS NMR spectra of various solids with natural isotopic abundances at high magnetic field (850 MHz), focusing on samples of amino acids, peptides, collagen, and various organic solids. The results show that high-resolution solid-state (2)H NMR can be used successfully to measure isotropic (1)H chemical shifts in favorable cases, particularly for mobile functional groups, such as methyl and -N(+)H(3) groups, and in some cases phenyl groups. Furthermore, we demonstrate that routine (2)H MAS NMR measurements can be exploited for assessing the relative dynamics of different functional groups in a molecule and for assessing whole-molecule motions in the solid state. The magnitude and field-dependence of second-order shifts due to the (2)H quadrupole interaction are also investigated, on the basis of analysis of simulated and experimental (1)H and (2)H MAS NMR spectra of fully deuterated and selectively deuterated samples of the α polymorph of glycine at two different magnetic field strengths.

  9. High Temperature, Wireless Seismometer Sensor for Venus

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Scardelletti, Maximilian C.; Taylor, Brandt; Beard, Steve; Meredith, Roger D.; Beheim, Glenn M.; Hunter Gary W.; Kiefer, Walter S.

    2012-01-01

    Space agency mission plans state the need to measure the seismic activity on Venus. Because of the high temperature on Venus (462? C average surface temperature) and the difficulty in placing and wiring multiple sensors using robots, a high temperature, wireless sensor using a wide bandgap semiconductor is an attractive option. This paper presents the description and proof of concept measurements of a high temperature, wireless seismometer sensor for Venus. A variation in inductance of a coil caused by the movement of an aluminum probe held in the coil and attached to a balanced leaf-spring seismometer causes a variation of 700 Hz in the transmitted signal from the oscillator/sensor system at 426? C. This result indicates that the concept may be used on Venus.

  10. Abundance and Temperature Dependency of Protein-Protein Interaction Revealed by Interface Structure Analysis and Stability Evolution.

    PubMed

    He, Yi-Ming; Ma, Bin-Guang

    2016-01-01

    Protein complexes are major forms of protein-protein interactions and implement essential biological functions. The subunit interface in a protein complex is related to its thermostability. Though the roles of interface properties in thermal adaptation have been investigated for protein complexes, the relationship between the interface size and the expression level of the subunits remains unknown. In the present work, we studied this relationship and found a positive correlation in thermophiles rather than mesophiles. Moreover, we found that the protein interaction strength in complexes is not only temperature-dependent but also abundance-dependent. The underlying mechanism for the observed correlation was explored by simulating the evolution of protein interface stability, which highlights the avoidance of misinteraction. Our findings make more complete the picture of the mechanisms for protein complex thermal adaptation and provide new insights into the principles of protein-protein interactions. PMID:27220911

  11. Abundance and Temperature Dependency of Protein-Protein Interaction Revealed by Interface Structure Analysis and Stability Evolution

    NASA Astrophysics Data System (ADS)

    He, Yi-Ming; Ma, Bin-Guang

    2016-05-01

    Protein complexes are major forms of protein-protein interactions and implement essential biological functions. The subunit interface in a protein complex is related to its thermostability. Though the roles of interface properties in thermal adaptation have been investigated for protein complexes, the relationship between the interface size and the expression level of the subunits remains unknown. In the present work, we studied this relationship and found a positive correlation in thermophiles rather than mesophiles. Moreover, we found that the protein interaction strength in complexes is not only temperature-dependent but also abundance-dependent. The underlying mechanism for the observed correlation was explored by simulating the evolution of protein interface stability, which highlights the avoidance of misinteraction. Our findings make more complete the picture of the mechanisms for protein complex thermal adaptation and provide new insights into the principles of protein-protein interactions.

  12. High-entropy alloys as high-temperature thermoelectric materials

    SciTech Connect

    Shafeie, Samrand; Guo, Sheng; Hu, Qiang; Fahlquist, Henrik; Erhart, Paul; Palmqvist, Anders

    2015-11-14

    Thermoelectric (TE) generators that efficiently recycle a large portion of waste heat will be an important complementary energy technology in the future. While many efficient TE materials exist in the lower temperature region, few are efficient at high temperatures. Here, we present the high temperature properties of high-entropy alloys (HEAs), as a potential new class of high temperature TE materials. We show that their TE properties can be controlled significantly by changing the valence electron concentration (VEC) of the system with appropriate substitutional elements. Both the electrical and thermal transport properties in this system were found to decrease with a lower VEC number. Overall, the large microstructural complexity and lower average VEC in these types of alloys can potentially be used to lower both the total and the lattice thermal conductivity. These findings highlight the possibility to exploit HEAs as a new class of future high temperature TE materials.

  13. High-entropy alloys as high-temperature thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Shafeie, Samrand; Guo, Sheng; Hu, Qiang; Fahlquist, Henrik; Erhart, Paul; Palmqvist, Anders

    2015-11-01

    Thermoelectric (TE) generators that efficiently recycle a large portion of waste heat will be an important complementary energy technology in the future. While many efficient TE materials exist in the lower temperature region, few are efficient at high temperatures. Here, we present the high temperature properties of high-entropy alloys (HEAs), as a potential new class of high temperature TE materials. We show that their TE properties can be controlled significantly by changing the valence electron concentration (VEC) of the system with appropriate substitutional elements. Both the electrical and thermal transport properties in this system were found to decrease with a lower VEC number. Overall, the large microstructural complexity and lower average VEC in these types of alloys can potentially be used to lower both the total and the lattice thermal conductivity. These findings highlight the possibility to exploit HEAs as a new class of future high temperature TE materials.

  14. Behavioral responses of Cao Vit gibbon (Nomascus nasutus) to variations in food abundance and temperature in Bangliang, Jingxi, China.

    PubMed

    Fan, Peng-Fei; Fei, Han-Lan; Ma, Chang-Yong

    2012-07-01

    The Cao Vit gibbon is a critically endangered species with only about 110 individuals remaining in a degraded karst forest along the China-Vietnam border. Behavioral data from this site are particularly useful in understanding gibbon behavioral adaptations to different sets of ecological conditions and will contribute to the conservation of the species. We studied seasonal variation in the time budget and diet of the Cao Vit gibbon in response to variation in food availability and ambient temperature by observing two groups for 1,379 hr between January and December 2009. We used 5-min scan samples to record the activity of gibbons. Both ambient temperature and food availability varied from month to month. Gibbon groups increased resting time and huddled together in sleeping places in cold months. Gibbons spent more time feeding on fruit when fruit was more abundant suggesting that fruit was their preferred food. Alternatively, leaf eating was negatively correlated with leaf availability which suggested that leaves may be used as a fallback food. Gibbons increased their diet diversity when they ate more leaves. This might be a strategy to cope with toxins or digestion inhibitor accumulation associated with feeding from a limited number of leaf species. Individuals consumed more buds when Broussonetia papyrifera produced buds in March and April. During this period, they decreased traveling time and engaged in less frequent social interactions. Gibbons spent more time searching for and feeding on invertebrates during June and October. However, we did not collect data on invertebrate abundance and therefore cannot determine the relationship between invertebrate feeding and availability. We conclude that flexibility in consuming diverse food types and food species, and in responding to the availability of preferred foods, has enabled the Cao Vit gibbon to survive in a degraded karst forest habitat.

  15. Fast vortex core switching at high temperatures

    NASA Astrophysics Data System (ADS)

    Lebecki, Kristof M.; Legut, Dominik

    2016-08-01

    Fast ferromagnetic vortex core switching is investigated employing micromagnetic simulations. Short pulse (in the range of a few hundreds of picoseconds) of an in-plane oscillating magnetic field is applied to a thin disk (diameter 200 nm and thickness 20 nm) with material parameters resembling permalloy. Fundamental frequency of this excitation field is close to the resonance with the material spin waves. Thermal effects are introduced by replacing the Landau-Lifshitz-Gilbert equation by the Landau-Lifshitz-Bloch equation. Temperature from 300 K to 850 K is considered, just below the Curie temperature TC = 870 K. Calculations are done within the OOMMF simulation framework. We find that: (i) Period of the field necessary to switch the vortex increases approximately from 141 ps at 300 K to 572 ps for the high-temperature limit. (ii) Amplitude of the field necessary to switch the vortex core decreases roughly from 60 mT to 15 mT - even at high temperatures this amplitude is nonzero, contrary to the case of quasi-static switching. (iii) Time span between the excitation and switching (switching time) seems not to depend on the temperature. (iv) Duration of the switching itself (movement of the Bloch point in the sample) increases from a few picoseconds at low temperatures to tens of picoseconds at high temperatures.

  16. Polychaete richness and abundance enhanced in anthropogenically modified estuaries despite high concentrations of toxic contaminants.

    PubMed

    Dafforn, Katherine A; Kelaher, Brendan P; Simpson, Stuart L; Coleman, Melinda A; Hutchings, Pat A; Clark, Graeme F; Knott, Nathan A; Doblin, Martina A; Johnston, Emma L

    2013-01-01

    Ecological communities are increasingly exposed to multiple chemical and physical stressors, but distinguishing anthropogenic impacts from other environmental drivers remains challenging. Rarely are multiple stressors investigated in replicated studies over large spatial scales (>1000 kms) or supported with manipulations that are necessary to interpret ecological patterns. We measured the composition of sediment infaunal communities in relation to anthropogenic and natural stressors at multiple sites within seven estuaries. We observed increases in the richness and abundance of polychaete worms in heavily modified estuaries with severe metal contamination, but no changes in the diversity or abundance of other taxa. Estuaries in which toxic contaminants were elevated also showed evidence of organic enrichment. We hypothesised that the observed response of polychaetes was not a 'positive' response to toxic contamination or a reduction in biotic competition, but due to high levels of nutrients in heavily modified estuaries driving productivity in the water column and enriching the sediment over large spatial scales. We deployed defaunated field-collected sediments from the surveyed estuaries in a small scale experiment, but observed no effects of sediment characteristics (toxic or enriching). Furthermore, invertebrate recruitment instead reflected the low diversity and abundance observed during field surveys of this relatively 'pristine' estuary. This suggests that differences observed in the survey are not a direct consequence of sediment characteristics (even severe metal contamination) but are related to parameters that covary with estuary modification such as enhanced productivity from nutrient inputs and the diversity of the local species pool. This has implications for the interpretation of diversity measures in large-scale monitoring studies in which the observed patterns may be strongly influenced by many factors that covary with anthropogenic modification.

  17. Polychaete Richness and Abundance Enhanced in Anthropogenically Modified Estuaries Despite High Concentrations of Toxic Contaminants

    PubMed Central

    Dafforn, Katherine A.; Kelaher, Brendan P.; Simpson, Stuart L.; Coleman, Melinda A.; Hutchings, Pat A.; Clark, Graeme F.; Knott, Nathan A.; Doblin, Martina A.; Johnston, Emma L.

    2013-01-01

    Ecological communities are increasingly exposed to multiple chemical and physical stressors, but distinguishing anthropogenic impacts from other environmental drivers remains challenging. Rarely are multiple stressors investigated in replicated studies over large spatial scales (>1000 kms) or supported with manipulations that are necessary to interpret ecological patterns. We measured the composition of sediment infaunal communities in relation to anthropogenic and natural stressors at multiple sites within seven estuaries. We observed increases in the richness and abundance of polychaete worms in heavily modified estuaries with severe metal contamination, but no changes in the diversity or abundance of other taxa. Estuaries in which toxic contaminants were elevated also showed evidence of organic enrichment. We hypothesised that the observed response of polychaetes was not a ‘positive’ response to toxic contamination or a reduction in biotic competition, but due to high levels of nutrients in heavily modified estuaries driving productivity in the water column and enriching the sediment over large spatial scales. We deployed defaunated field-collected sediments from the surveyed estuaries in a small scale experiment, but observed no effects of sediment characteristics (toxic or enriching). Furthermore, invertebrate recruitment instead reflected the low diversity and abundance observed during field surveys of this relatively ‘pristine’ estuary. This suggests that differences observed in the survey are not a direct consequence of sediment characteristics (even severe metal contamination) but are related to parameters that covary with estuary modification such as enhanced productivity from nutrient inputs and the diversity of the local species pool. This has implications for the interpretation of diversity measures in large-scale monitoring studies in which the observed patterns may be strongly influenced by many factors that covary with anthropogenic

  18. High-temperature testing of high performance fiber reinforced concrete

    NASA Astrophysics Data System (ADS)

    Fořt, Jan; Vejmelková, Eva; Pavlíková, Milena; Trník, Anton; Čítek, David; Kolísko, Jiří; Černý, Robert; Pavlík, Zbyšek

    2016-06-01

    The effect of high-temperature exposure on properties of High Performance Fiber Reinforced Concrete (HPFRC) is researched in the paper. At first, reference measurements are done on HPFRC samples without high-temperature loading. Then, the HPFRC samples are exposed to the temperatures of 200, 400, 600, 800, and 1000 °C. For the temperature loaded samples, measurement of residual mechanical and basic physical properties is done. Linear thermal expansion coefficient as function of temperature is accessed on the basis of measured thermal strain data. Additionally, simultaneous difference scanning calorimetry (DSC) and thermogravimetry (TG) analysis is performed in order to observe and explain material changes at elevated temperature. It is found that the applied high temperature loading significantly increases material porosity due to the physical, chemical and combined damage of material inner structure, and negatively affects also the mechanical strength. Linear thermal expansion coefficient exhibits significant dependence on temperature and changes of material structure. The obtained data will find use as input material parameters for modelling the damage of HPFRC structures exposed to the fire and high temperature action.

  19. Temperature and abundances in the Jovian auroral stratosphere. 2: Ethylene as a probe of the microbar region

    NASA Technical Reports Server (NTRS)

    Kostiuk, Theodor; Romani, Paul; Espenak, Fred; Livengood, Timothy A.

    1993-01-01

    Individual emission lines of ethylene (C2H4) near 10.5 micron were measured from the equatorial and north polar regions of Jupiter. Observations were made at a spectral resolution of 0.00083/cm using infrared heterodyne spectroscopy at the NASA Infrared Telescope Facility of Mauna Kea, Hawaii. The line shape information possible with this resolving power permitted the retrieval of quiescent ethylene abundances and the investigation of abundance and thermal structure variability in the polar auroral region. A rough distribution of the north polar emission as a function of longitude was obtained with an instantaneous field of view (full width at half maximum) of approximately 1 arc sec on the planet. The greatest C2H4 emission was observed near the nominal north polar methane hot spot (60 deg N, 180 deg longitude, System III, 1965). It was found to be confined to less than 10 deg longitude on the planet. Using a Voyager-derived thermal profile, retrieved ethylene mole fractions for equatorial and north polar quiescent (non-hot spot) regions were consistent with results from existing photochemical models. At the hot spot an 18-fold increase in abundance was required near the 10-microbar level to reproduce the data. Alternatively varying the stratospheric thermal profile, a 67-137 K increase in temperature was required at the approximately 10-microbar level to satisfy the observed emission, if the C2H4 mole fraction is fixed to the quiescent value. These results provide the first direct probe of the upper stratosphere of Jupiter and give upper limits to the temperature increase near the source of the north polar thermal infrared aurora. Combined with results from similar measurements of auroral ethane emission (Livengood et al., this issue) probing the 1-mbar region, altitude information on the thermal structure can be obtained for the first time. The ethylene line emission region extends to the few microbar pressure level and may overlap the region where the H2

  20. Petrogenesis of high-CaO lavas from Mauna Kea, Hawaii: Constraints from trace element abundances

    NASA Astrophysics Data System (ADS)

    Huang, Shichun; Humayun, Munir

    2016-07-01

    The role of a mafic component in the petrogenesis of Oceanic Island Basalts (OIBs) is highly debated. As the best studied OIB, Hawaiian lavas provide critical insights into OIB genesis. At a given MgO content, the CaO content in the melt has been used to distinguish between partial melts of peridotite and garnet pyroxenite/eclogite. However, calculations using the BATCH program show that CaO contents in volatile-free melts saturated with all four phases, garnet, clinopyroxene, orthopyroxene and olivine, are controlled by both degrees of partial melting and source compositions, and low melt CaO content is not diagnostic of partial melts from garnet pyroxenite/eclogite. This is an important consideration in understanding the origin of high-CaO lavas recovered from the Hawaii Scientific Drilling Project (HSDP). Detailed geochemical and isotopic studies have been focused on the HSDP high- and low-SiO2 group lavas, and high-CaO lavas were not well studied because they were not included in the original reference suite samples. Here, we report trace element abundances obtained on a suite of high-CaO glasses and compared the trace element abundances of high-CaO lavas to those in high- and low-SiO2 lavas. When normalized to the average composition of low-SiO2 lavas, high-CaO lavas form a U-shaped trace element pattern, enriched in both the most incompatible (Nb, Th) and the least incompatible (Sc, V) elements. This compositional distinction is best explained if high-CaO parental magma represents a mixture of a low degree partial melt of the low-SiO2 mantle source with a high degree (>80%) partial melt derived from a mafic cumulate component. This mafic cumulate must be clinopyroxene-rich, and it could be delaminated mafic cumulate formed under arcs during continent formation, lower continental crust, recycled lower oceanic crust, or high pressure cumulates from a magma chamber.

  1. Impact of short-term storage temperature on determination of microbial community composition and abundance in aerated forest soil and anoxic pond sediment samples.

    PubMed

    Brandt, Franziska B; Breidenbach, Björn; Brenzinger, Kristof; Conrad, Ralf

    2014-12-01

    Sampling strategy is important for unbiased analysis of the characteristics of microbial communities in the environment. During field work it is not always possible to analyze fresh samples immediately or store them frozen. Therefore, the effect of short-term storage temperature was investigated on the abundance and composition of bacterial, archaeal and denitrifying communities in environmental samples from two different sampling sites. Oxic forest soil and anoxic pond sediment were investigated by measuring microbial abundance (DNA) and transcriptional activity (RNA). Prior to investigating the effect of storage temperature, samples were immediately analyzed, in order to represent the original situation in the habitat. The effect of storage temperature was then determined after 11 days at different low temperatures (room temperature, 4 °C, −22 °C and −80 °C). Community profiling using terminal restriction fragment length polymorphism (T-RFLP) showed no significant differences between the immediately analyzed reference sample and the samples stored at different incubation temperatures, both for DNA and RNA extracts. The abundance of microbial communities was determined using quantitative PCR and it also revealed a stable community size at all temperatures tested. By contrast, incubation at an elevated temperature (37 °C) resulted in changed bacterial community composition. In conclusion, short-term storage, even at room temperature, did not affect microbial community composition, abundance and transcriptional activity in aerated forest soil and anoxic pond sediment.

  2. High Temperature Calibration Furnace System user's guide

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The High Temperature Calibration Furnace System (HTCFS) was developed by Summitec Corporation. It is a high precision instrument providing a constant temperature which can be used to calibrate high temperature thermocouples. Incorporating the many recent technological advances from the fields of optical fiber thermometry, material science, computer systems interfacing, and process control, the engineers at Summitec Corporation have been able to create a system that can reach a steady operating temperature of 1700 C. The precision for the system requires the measurement of temperature to be within 1 C in two hours and within 2 C in 24 hours. As documented, the experimental result shows that this system has been able to stay within .5 C in 5 hours. No other systems commercially available have been able to achieve such high temperature precision. This manual provides an overview of the system design, instructions for instrument setup, and operation procedures. Also included are a vendor list and the source codes for the custom-designed software.

  3. High Temperature VARTM of Phenylethynyl Terminated Imides

    NASA Technical Reports Server (NTRS)

    Ghose, Sayata; Watson, Kent A.; Cano, Roberto J.; Britton, Sean M.; Jensen, Brian J.; Connell, John W.; Herring, Helen M.; Linberry, Quentin J.

    2009-01-01

    LaRC phenylethynyl terminated imide (PETI) resins were processed into composites using high temperature vacuum assisted resin transfer molding (VARTM). Although initial runs yielded composites with high void content, process modifications reduced voids to <3%. Photomicrographs were taken and void contents and T(sub g)s of the panels were determined.

  4. High-temperature helium-loop facility

    SciTech Connect

    Tokarz, R.D.

    1981-09-01

    The high-temperature helium loop is a facility for materials testing in ultrapure helium gas at high temperatures. The closed loop system is capable of recirculating high-purity helium or helium with controlled impurities. The gas loop maximum operating conditions are as follows: 300 psi pressure, 500 lb/h flow rate, and 2100/sup 0/F temperature. The two test sections can accept samples up to 3.5 in. diameter and 5 ft long. The gas loop is fully instrumented to continuously monitor all parameters of loop operation as well as helium impurities. The loop is fully automated to operate continuously and requires only a daily servicing by a qualified operator to replenish recorder charts and helium makeup gas. Because of its versatility and high degree of parameter control, the helium loop is applicable to many types of materials research. This report describes the test apparatus, operating parameters, peripheral systems, and instrumentation system.

  5. Study of high temperature oxide superconductors

    NASA Astrophysics Data System (ADS)

    Wu, M. K.; Ashburn, J. R.; Higgins, C. A.; Carswell, W. E.; Loo, B. H.; Burns, D. H.; Ibrahim, A.; Rolin, T.; Peters, P. N.; Sisk, R. C.

    1988-01-01

    Experimental studies are reported whose results indicate that proper processing procedures are critical to the formation of high-temperature copper oxide superconductors. Superconducting 123 films can be fabricated using the green 211 phase as a substrate. The transition temperature and transition width characteristics of these films are better than those obtained when other oxide compounds are used as substrates. A compact or single-crystal 211 phase will be desirable as a substrate for high-quality thin films. A new high T(c) copper oxide compound with nonrare earth elements was prepared using high-temperature processing. A YBa2Cu3O7-Ag composite with improved electrical conductivity was also prepared.

  6. High-temperature bulk acoustic wave sensors

    NASA Astrophysics Data System (ADS)

    Fritze, Holger

    2011-01-01

    Piezoelectric crystals like langasite (La3Ga5SiO14, LGS) and gallium orthophosphate (GaPO4) exhibit piezoelectrically excited bulk acoustic waves at temperatures of up to at least 1450 °C and 900 °C, respectively. Consequently, resonant sensors based on those materials enable new sensing approaches. Thereby, resonant high-temperature microbalances are of particular interest. They correlate very small mass changes during film deposition onto resonators or gas composition-dependent stoichiometry changes of thin films already deposited onto the resonators with the resonance frequency shift of such devices. Consequently, the objective of the work is to review the high-temperature properties, the operation limits and the measurement principles of such resonators. The electromechanical properties of high-temperature bulk acoustic wave resonators such as mechanical stiffness, piezoelectric and dielectric constant, effective viscosity and electrical conductivity are described using a one-dimensional physical model and determined accurately up to temperatures as close as possible to their ultimate limit. Insights from defect chemical models are correlated with the electromechanical properties of the resonators. Thereby, crucial properties for stable operation as a sensor under harsh conditions are identified to be the formation of oxygen vacancies and the bulk conductivity. Operation limits concerning temperature, oxygen partial pressure and water vapor pressure are given. Further, application-relevant aspects such as temperature coefficients, temperature compensation and mass sensitivity are evaluated. In addition, approximations are introduced which make the exact model handy for routine data evaluation. An equivalent electrical circuit for high-temperature resonator devices is derived based on the one-dimensional physical model. Low- and high-temperature approximations are introduced. Thereby, the structure of the equivalent circuit corresponds to the Butterworth

  7. High-resolution abundance analysis of very metal-poor r-I stars

    NASA Astrophysics Data System (ADS)

    Siqueira Mello, C.; Hill, V.; Barbuy, B.; Spite, M.; Spite, F.; Beers, T. C.; Caffau, E.; Bonifacio, P.; Cayrel, R.; François, P.; Schatz, H.; Wanajo, S.

    2014-05-01

    Context. Moderately r-process-enriched stars (r-I; +0.3 ≤ [Eu/Fe] ≤ +1.0) are at least four times as common as those that are greatly enriched in r-process elements (r-II; [Eu/Fe] > +1.0), and the abundances in their atmospheres are important tools for obtaining a better understanding of the nucleosynthesis processes responsible for the origin of the elements beyond the iron peak. Aims: The main aim of this work is to derive abundances for a sample of seven metal-poor stars with -3.4 ≤ [Fe/H] ≤ -2.4 classified as r-I stars, to understand the role of these stars for constraining the astrophysical nucleosynthesis event(s) that is (are) responsible for the production of the r-process, and to investigate whether they differ, in any significant way, from the r-II stars. Methods: We carried out a detailed abundance analysis based on high-resolution spectra obtained with the VLT/UVES spectrograph, using spectra in the wavelength ranges 3400-4500 Å, 6800-8200 Å, and 8700-10 000 Å, with resolving power R ~ 40 000 (blue arm) and R ~ 55 000 (red arm). The OSMARCS LTE 1D model atmosphere grid was employed, along with the spectrum synthesis code Turbospectrum. Results: We have derived abundances of the light elements Li, C, and N, the α-elements Mg, Si, S, Ca, and Ti, the odd-Z elements Al, K, and Sc, the iron-peak elements V, Cr, Mn, Fe, Co, and Ni, and the trans-iron elements from the first peak (Sr, Y, Zr, Mo, Ru, and Pd), the second peak (Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb), the third peak (Os and Ir, as upper limits), and the actinides (Th) regions. The results are compared with values for these elements for r-II and "normal" very and extremely metal-poor stars reported in the literature, ages based on radioactive chronometry are explored using different models, and a number of conclusions about the r-process and the r-I stars are presented. Hydrodynamical models were used for some elements, and general behaviors for the 3D corrections

  8. Discovery of earth-abundant nitride semiconductors by computational screening and high-pressure synthesis

    NASA Astrophysics Data System (ADS)

    Hinuma, Yoyo; Hatakeyama, Taisuke; Kumagai, Yu; Burton, Lee A.; Sato, Hikaru; Muraba, Yoshinori; Iimura, Soshi; Hiramatsu, Hidenori; Tanaka, Isao; Hosono, Hideo; Oba, Fumiyasu

    2016-06-01

    Nitride semiconductors are attractive because they can be environmentally benign, comprised of abundant elements and possess favourable electronic properties. However, those currently commercialized are mostly limited to gallium nitride and its alloys, despite the rich composition space of nitrides. Here we report the screening of ternary zinc nitride semiconductors using first-principles calculations of electronic structure, stability and dopability. This approach identifies as-yet-unreported CaZn2N2 that has earth-abundant components, smaller carrier effective masses than gallium nitride and a tunable direct bandgap suited for light emission and harvesting. High-pressure synthesis realizes this phase, verifying the predicted crystal structure and band-edge red photoluminescence. In total, we propose 21 promising systems, including Ca2ZnN2, Ba2ZnN2 and Zn2PN3, which have not been reported as semiconductors previously. Given the variety in bandgaps of the identified compounds, the present study expands the potential suitability of nitride semiconductors for a broader range of electronic, optoelectronic and photovoltaic applications.

  9. Discovery of earth-abundant nitride semiconductors by computational screening and high-pressure synthesis.

    PubMed

    Hinuma, Yoyo; Hatakeyama, Taisuke; Kumagai, Yu; Burton, Lee A; Sato, Hikaru; Muraba, Yoshinori; Iimura, Soshi; Hiramatsu, Hidenori; Tanaka, Isao; Hosono, Hideo; Oba, Fumiyasu

    2016-01-01

    Nitride semiconductors are attractive because they can be environmentally benign, comprised of abundant elements and possess favourable electronic properties. However, those currently commercialized are mostly limited to gallium nitride and its alloys, despite the rich composition space of nitrides. Here we report the screening of ternary zinc nitride semiconductors using first-principles calculations of electronic structure, stability and dopability. This approach identifies as-yet-unreported CaZn2N2 that has earth-abundant components, smaller carrier effective masses than gallium nitride and a tunable direct bandgap suited for light emission and harvesting. High-pressure synthesis realizes this phase, verifying the predicted crystal structure and band-edge red photoluminescence. In total, we propose 21 promising systems, including Ca2ZnN2, Ba2ZnN2 and Zn2PN3, which have not been reported as semiconductors previously. Given the variety in bandgaps of the identified compounds, the present study expands the potential suitability of nitride semiconductors for a broader range of electronic, optoelectronic and photovoltaic applications. PMID:27325228

  10. Comparisons among survey methodologies to test for abundance and size of a highly targeted fish species.

    PubMed

    Gardner, J P A; Struthers, C D

    2013-01-01

    Three sampling methods for estimating abundance and size of blue cod Parapercis colias were compared inside and outside Kapiti Marine Reserve, New Zealand (40° 49' 31·77('') S; 174° 55' 02·87('') E). Two baited methods, baited underwater video (BUV) and experimental angling (EA), were more efficient and had lower levels of estimate variation than diver-based underwater visual census (UVC). The BUV and EA recorded more fish and of greater size ranges than UVC, and also had fewer zero count replicates. The BUV and EA methodologies revealed highly significant differences in abundance and size of fish between sites (reserve v. non-reserve), whereas UVC revealed no such differences. These results indicate that BUV is likely to be the most accurate, cost-effective and easy to use methodology for the surveying of carnivorous temperate reef fishes for future monitoring. It is noted, however, that new data acquired using the BUV methodology may need to be compared over a calibration period to data acquired using the UVC methodology to ensure that historical data sets derived from UVC still have validity and application for future monitoring activity.

  11. Discovery of earth-abundant nitride semiconductors by computational screening and high-pressure synthesis

    PubMed Central

    Hinuma, Yoyo; Hatakeyama, Taisuke; Kumagai, Yu; Burton, Lee A.; Sato, Hikaru; Muraba, Yoshinori; Iimura, Soshi; Hiramatsu, Hidenori; Tanaka, Isao; Hosono, Hideo; Oba, Fumiyasu

    2016-01-01

    Nitride semiconductors are attractive because they can be environmentally benign, comprised of abundant elements and possess favourable electronic properties. However, those currently commercialized are mostly limited to gallium nitride and its alloys, despite the rich composition space of nitrides. Here we report the screening of ternary zinc nitride semiconductors using first-principles calculations of electronic structure, stability and dopability. This approach identifies as-yet-unreported CaZn2N2 that has earth-abundant components, smaller carrier effective masses than gallium nitride and a tunable direct bandgap suited for light emission and harvesting. High-pressure synthesis realizes this phase, verifying the predicted crystal structure and band-edge red photoluminescence. In total, we propose 21 promising systems, including Ca2ZnN2, Ba2ZnN2 and Zn2PN3, which have not been reported as semiconductors previously. Given the variety in bandgaps of the identified compounds, the present study expands the potential suitability of nitride semiconductors for a broader range of electronic, optoelectronic and photovoltaic applications. PMID:27325228

  12. NDE standards for high temperature materials

    NASA Technical Reports Server (NTRS)

    Vary, Alex

    1991-01-01

    High temperature materials include monolithic ceramics for automotive gas turbine engines and also metallic/intermetallic and ceramic matrix composites for a range of aerospace applications. These are materials that can withstand extreme operating temperatures that will prevail in advanced high-efficiency gas turbine engines. High temperature engine components are very likely to consist of complex composite structures with three-dimensionality interwoven and various intermixed ceramic fibers. The thermomechanical properties of components made of these materials are actually created in-place during processing and fabrication stages. The complex nature of these new materials creates strong incentives for exact standards for unambiguous evaluations of defects and microstructural characteristics. NDE techniques and standards that will ultimately be applicable to production and quality control of high temperature materials and structures are still emerging. The needs range from flaw detection to below 100 micron levels in monolithic ceramics to global imaging of fiber architecture and matrix densification anomalies in composites. The needs are different depending on the processing stage, fabrication method, and nature of the finished product. The standards are discussed that must be developed in concert with advances in NDE technology, materials processing research, and fabrication development. High temperature materials and structures that fail to meet stringent specifications and standards are unlikely to compete successfully either technologically or in international markets.

  13. High-Temperature Solar Cell Development

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Raffaelle, Ryne P.; Merritt, Danielle

    2004-01-01

    The vast majority of satellites and near-earth probes developed to date have relied upon photovoltaic power generation. If future missions to probe environments close to the sun will be able to use photovoltaic power, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. For example, the equilibrium temperature of a Mercury surface station will be about 450 C, and the temperature of solar arrays on the proposed "Solar Probe" mission will extend to temperatures as high as 2000 C (although it is likely that the craft will operate on stored power rather than solar energy during the closest approach to the sun). Advanced thermal design principles, such as replacing some of the solar array area with reflectors, off-pointing, and designing the cells to reflect rather than absorb light out of the band of peak response, can reduce these operating temperature somewhat. Nevertheless, it is desirable to develop approaches to high-temperature solar cell design that can operate under temperature extremes far greater than today's cells. Solar cells made from wide bandgap (WBG) compound semiconductors are an obvious choice for such an application. In order to aid in the experimental development of such solar cells, we have initiated a program studying the theoretical and experimental photovoltaic performance of wide bandgap materials. In particular, we have been investigating the use of GaP, SiC, and GaN materials for space solar cells. We will present theoretical results on the limitations on current cell technologies and the photovoltaic performance of these wide-bandgap solar cells in a variety of space conditions. We will also give an overview of some of NASA's cell developmental efforts in this area and discuss possible future mission applications.

  14. High temperature thrust chamber for spacecraft

    NASA Technical Reports Server (NTRS)

    Chazen, Melvin L. (Inventor); Mueller, Thomas J. (Inventor); Kruse, William D. (Inventor)

    1998-01-01

    A high temperature thrust chamber for spacecraft (20) is provided herein. The high temperature thrust chamber comprises a hollow body member (12) having an outer surface and an internal surface (16) defining the high temperature chamber (10). The body member (12) is made substantially of rhenium. An alloy (18) consisting of iridium and at least alloying metal selected of the group consisting of rhodium, platinum and palladium is deposited on at least a portion of the internal surface (16) of the body member (12). The iridium and the alloying metal are electrodeposited onto the body member (12). A HIP cycle is performed upon the body member (12) to cause the coating of iridium and the alloying metal to form the alloy (18) which protects the body member (12) from oxidation.

  15. High-temperature geothermal reservoir engineering

    SciTech Connect

    Schroeder, R.C.; Benson, S.; Goranson, C.

    1980-02-01

    A review of high-temperature geothermal reservoir engineering is presented. High-temperature downhole conditions encountered during field activities are reviewed with data from Cerro Prieto as the primary example. The types of measurements required for estimation of formation parameter values and how they depend on other geoscience data are reviewed. The analysis techniques that are currently used to evaluate field data are discussed and their limitations, applicability, and associated difficulties are described using data from Cerro Prieto as an example. Downhole tools that are needed for high-temperature measurements are discussed with a review of the current state of the art. The use of measured data in reservoir engineering simulation calculations is summarized, and different numerical models are reviewed. Data from Cerro Prieto are used as an example to show how reserves and reservoir depletion calculations can be used to aid the field developer in choosing operational field strategies.

  16. High Temperature Membrane & Advanced Cathode Catalyst Development

    SciTech Connect

    Protsailo, Lesia

    2006-04-20

    Current project consisted of three main phases and eighteen milestones. Short description of each phase is given below. Table 1 lists program milestones. Phase 1--High Temperature Membrane and Advanced Catalyst Development. New polymers and advanced cathode catalysts were synthesized. The membranes and the catalysts were characterized and compared against specifications that are based on DOE program requirements. The best-in-class membranes and catalysts were downselected for phase 2. Phase 2--Catalyst Coated Membrane (CCM) Fabrication and Testing. Laboratory scale catalyst coated membranes (CCMs) were fabricated and tested using the down-selected membranes and catalysts. The catalysts and high temperature membrane CCMs were tested and optimized. Phase 3--Multi-cell stack fabrication. Full-size CCMs with the down-selected and optimized high temperature membrane and catalyst were fabricated. The catalyst membrane assemblies were tested in full size cells and multi-cell stack.

  17. Low toxicity high temperature PMR polyimide

    NASA Technical Reports Server (NTRS)

    Pater, Ruth H. (Inventor)

    1992-01-01

    In-situ polymerization of monomer reactants (PMR) type polyimides constitute an important class of ultra high performance composite matrix resins. PMR-15 is the best known and most widely used PMR polyimide. An object of the present invention is to provide a substantially improved high temperature PMR-15 system that exhibits better processability, toughness, and thermo-oxidative stability than PMR-15, as well as having a low toxicity. Another object is to provide new PMR polyimides that are useful as adhesives, moldings, and composite matrices. By the present invention, a new PMR polyimide comprises a mixture of the following compounds: 3,4'-oxydianiline (3,4'-ODA), NE, and BTDE which are then treated with heat. This PMR was designated LaRC-RP46 and has a broader processing window, better reproducibility of high quality composite parts, better elevated temperature mechanical properties, and higher retention of mechanical properties at an elevated temperature, particularly, at 371 C.

  18. Containerless measurements on liquids at high temperatures

    NASA Technical Reports Server (NTRS)

    Weber, Richard

    1993-01-01

    The application of containerless techniques for measurements of the thermophysical properties of high temperature liquids is reviewed. Recent results obtained in the materials research laboratories at Intersonics are also presented. Work to measure high temperature liquid properties is motivated by both the need for reliable property data for modeling of industrial processes involving molten materials and generation of data form basic modeling of materials behavior. The motivation for this work and examples of variations in thermophysical property values from the literature are presented. The variations may be attributed to changes in the specimen properties caused by chemical changes in the specimen and/or to measurement errors. The two methods used to achieve containerless conditions were aeroacoustic levitation and electromagnetic levitation. Their qualities are presented. The accompanying slides show the layout of levitation equipment and present examples of levitated metallic and ceramic specimens. Containerless techniques provide a high degree of control over specimen chemistry, nucleation and allow precise control of liquid composition to be achieved. Effects of minor additions can thus be measured in a systematic way. Operation in reduced gravity enables enhanced control of liquid motion which can allow measurement of liquid transport properties. Examples of nucleation control, the thermodynamics of oxide contamination removal, and control of the chromium content of liquid aluminum oxide by high temperature containerless processes are presented. The feasibility of measuring temperature, emissivity, liquidus temperature, enthalpy, surface tension, density, viscosity, and thermal diffusivity are discussed in the final section of the paper.

  19. Micromechanics of high temperature deformation and failure

    NASA Technical Reports Server (NTRS)

    Nasser, S. N.; Weertman, J. R.

    1985-01-01

    The micromechanics of the constitutive behavior of elastoplastic materials at high temperatures was examined. The experimental work focused on the development of microscopic defects in superalloys (Waspaloy), especially the formation of voids at grain boundary carbides, and slip induced surface cracks within grains upon cyclic loading at high temperatures. The influence of these defects on the life expectancy of the material was examined. The theoretical work consists of two parts: (1) analytical description of the mechanisms that lead to defects observed experimentally; and (2) development of macroscopic elastoplastic nonlinear constitutive relations based on mechanical modeling.

  20. Joining of ceramics for high temperature applications

    NASA Technical Reports Server (NTRS)

    Vilpas, Martti

    1987-01-01

    Summarized is a literature survey of the methods for joining ceramics to ceramics or ceramics to metals for high temperature applications. Also mechanical properties and potential applications of the joints are considered. The joining of ceramics is usually carried out by brazing or diffusion bonding. Especially the latter has been found useful, increasing the application of bonded ceramics. The possibility of using electron beam and laser beam welding for joining ceramics has also recently been investigated. The bonding of ceramics has found numerous applications typical for high operating temperatures, i.e., sensors and thermocouples.

  1. Introduction to high-temperature superconductivity

    SciTech Connect

    Sheahen, T.P.

    1994-12-31

    The Electric Power Research Institute, as part of its program to develop high-temperature superconductivity applications for the power industry, has endevoured to educate utility engineers and executives on superconductivity. This book is a series of tutorials prepared by the Argonne National Laboratory. Part one is at an introductory level, asking and answering the question `What is superconductivity?` Part 2 is an exposition of the basic properties of the new materials - structure, phase equilibria, effects of doping, etc. with consideration of theoretical issues. Part 3 covers potential practical uses of high temperature superconductors.

  2. High-temperature MAS-NMR at high spinning speeds.

    PubMed

    Kirchhain, Holger; Holzinger, Julian; Mainka, Adrian; Spörhase, Andreas; Venkatachalam, Sabarinathan; Wixforth, Achim; van Wüllen, Leo

    2016-09-01

    A low cost version to enable high temperature MAS NMR experiments at temperatures of up to 700°C and spinning speeds of up to 10kHz is presented. The method relies on inductive heating using a metal coated rotor insert. The metal coating is accomplished via a two step process involving physical vapor deposition and galvanization.

  3. Geographic distribution and relative abundance of the invasive glassy-winged sharpshooter: effects of temperature and egg parasitoids.

    PubMed

    Gutierrez, Andrew Paul; Ponti, Luigi; Hoddle, Mark; Almeida, Rodrigo P P; Irvin, Nicola A

    2011-08-01

    The capacity to predict the geographic distribution and relative abundance of invasive species is pivotal to developing policy for eradication or control and management. Commonly used methods fall under the ambit of ecological niche models (ENMs). These methods were reviewed and shortcomings identified. Weather-driven physiologically based demographic models (PBDMs) are proposed that resolve many of the deficiencies of ENMs. The PBDM approach is used to analyze the invasiveness of the polyphagous glassy-winged sharpshooter (Homalodisca vitripennis [Germar]), a pest native to the southeastern United States and northeastern Mexico that extended its range into California in 1989. Glassy-winged sharpshooter vectors the pathogenic bacterium, Xylella fastidiosa (Wells) that causes Pierce's disease in grape and scorch-like diseases in other plants. PBDMs for glassy-winged sharpshooter and its egg parasitoids (Gonatocerus ashmeadi Girault and G. triguttatus Girault) were developed and linked to a PBDM for grape published by Wermelinger et al. (1991). Daily weather data from 108 locations across California for the period 1995-2006 were used to drive the PBDM system, and GRASS GIS was used to map the simulation results. The geographic distribution of glassy-winged sharpshooter, as observed, is predicted to be largely restricted to the warm areas of southern California, with the action of the two egg parasitoids reducing its abundance >90%. The average indispensable mortality contributed by G. triguttatus is <1%. A temperature-dependent developmental rate model for X. fastidiosa was developed that suggests its geographic range is also limited to the warm inland areas of southern California. Biological control of glassy-winged sharpshooter further decreases the pathogen's relative range. Climate warming scenarios of +2°C and +3°C suggest that the distribution and severity of glassy-winged sharpshooter and X. fastidiosa will increase in the agriculturally rich central valley

  4. Fiber Bragg Grating Filter High Temperature Sensors

    NASA Technical Reports Server (NTRS)

    Lyons, Donald R.; Brass, Eric D.; Pencil, Eric (Technical Monitor)

    2001-01-01

    We present a scaled-down method for determining high temperatures using fiber-based Bragg gratings. Bragg gratings are distributed along the length of the optical fiber, and have high reflectivities whenever the optical wavelength is twice the grating spacing. These spatially distinct Bragg regions (located in the core of a fiber) are sensitive to local temperature changes. Since these fibers are silica-based they are easily affected by localized changes in temperature, which results in changes to both the grating spacing and the wavelength reflectivity. We exploit the shift in wavelength reflectivity to measure the change in the local temperature. Note that the Bragg region (sensing area) is some distance away from where the temperature is being measured. This is done so that we can measure temperatures that are much higher than the damage threshold of the fiber. We do this by affixing the fiber with the Bragg sensor to a material with a well-known coefficient of thermal expansion, and model the heat gradient from the region of interest to the actual sensor. The research described in this paper will culminate in a working device as well as be the second portion of a publication pending submission to Optics Letters.

  5. Light Scattering on the High Temperature Superconductors

    NASA Astrophysics Data System (ADS)

    Slakey, Francis

    The high temperature superconductors have been examined by the technique of Raman scattering in several limits: the insulating phase, the normal and superconducting state of the superconducting phase, and an optically induced metastable phase. In all cases, the analysis and proposed phenomenological models involved either an examination of the inelastic background scattering or the phonon excitation spectrum. Specifically, the character, temperature dependence, critical temperature dependence and the copper-oxygen covalency dependence of the inelastic background scattering has been studied in all three phases. Analysis of the superconducting phase reveals a marginal Fermi-liquid like character of the electronic polarizability, and a decidedly non-traditional shift of the scattering intensity of the electronic excitations at low temperature. On removing oxygen, the system passes through a metal-insulator transition and the inelastic background becomes dominantly magnetic in origin. Examinations of the 'allowed' Raman active phonons in the superconducting phase expose a strong coupling of two modes to the background electronic excitation spectrum, and a dramatic renormalization of these modes below T _{rm c}. Further, two sharply resonant Raman 'forbidden' modes can be bleached out of the spectrum at low temperature with a sufficiently high laser dosage. A transition from this optically induced metastable state to the normal state occurs on warming the crystal back to room temperature. On reducing the oxygen concentration, the coupling strength of the two asymmetric phonons diminishes rapidly, the renormalization effects vanish, and the compound no longer exhibits metastability.

  6. Chemical abundances in the protoplanetary disc LV 2 (Orion) - II. High-dispersion VLT observations and microjet properties

    NASA Astrophysics Data System (ADS)

    Tsamis, Y. G.; Walsh, J. R.

    2011-11-01

    Integral field spectroscopy of the LV 2 proplyd is presented taken with the Very Large Telescope (VLT)/FLAMES Argus array at an angular resolution of 0.31 × 0.31 arcsec2 and velocity resolutions down to 2 km s-1 pixel-1. Following subtraction of the local M42 emission, the spectrum of LV 2 is isolated from the surrounding nebula. We measured the heliocentric velocities and widths of a number of lines detected in the intrinsic spectrum of the proplyd, as well as in the adjacent Orion nebula falling within a 6.6 × 4.2 arcsec2 field of view. It is found that far-ultraviolet to optical collisional lines with critical densities, Ncr, ranging from 103 to 109 cm-3 suffer collisional de-excitation near the rest velocity of the proplyd correlating tightly with their critical densities. Lines of low Ncr are suppressed the most. The bipolar jet arising from LV 2 is spectrally and spatially well detected in several emission lines. We compute the [O III] electron temperature profile across LV 2 in velocity space and measure steep temperature variations associated with the red-shifted lobe of the jet, possibly being due to a shock discontinuity. From the velocity-resolved analysis the ionized gas near the rest frame of LV 2 has Te= 9200 ± 800 K and Ne˜ 106 cm-3, while the red-shifted jet lobe has Te≈ 9000-104 K and Ne˜ 106-107 cm-3. The jet flow is highly ionized but contains dense semineutral clumps emitting neutral oxygen lines. The abundances of N+, O2 +, Ne2 +, Fe2 +, S+and S2 +are measured for the strong red-shifted jet lobe. Iron in the core of LV 2 is depleted by 2.54 dex with respect to solar as a result of sedimentation on dust, whereas the efficient destruction of dust grains in the fast microjet raises its Fe abundance to at least 30 per cent solar. Sulphur does not show evidence of significant depletion on dust, but its abundance both in the core and the jet is only about half solar. Based on observations made with ESO telescopes at the Paranal Observatory

  7. High Temperature Mechanisms for Venus Exploration

    NASA Astrophysics Data System (ADS)

    Ji, Jerri; Narine, Roop; Kumar, Nishant; Singh, Sase; Gorevan, Steven

    Future Venus missions, including New Frontiers Venus In-Situ Explorer and three Flagship Missions - Venus Geophysical Network, Venus Mobile Explorer and Venus Surface Sample Return all focus on searching for evidence of past climate change both on the surface and in the atmospheric composition as well as in the interior dynamics of the planet. In order to achieve these goals and objectives, many key technologies need to be developed for the Venus extreme environment. These key technologies include sample acquisition systems and other high-temperature mechanisms and mobility systems capable of extended operation when directly exposed to the Venus surface or lower atmosphere environment. Honeybee Robotics has developed two types of high temperature motors, the materials and components in both motors were selected based on the requirement to survive temperatures above a minimum of 460° C, at earth atmosphere. The prototype Switched Reluctance Motor (SRM) has been operated non-continuously for over 20 hours at Venus-like conditions (460° C temperature, mostly CO2 gas environment) and it remains functional. A drilling system, actuated by two SRMs was tested in Venus-like conditions, 460° C temperature and mostly CO2 gas environment, for more than 15 hours. The drill successfully completed three tests by drilling into chalk up to 6 inches deep in each test. A first generation Brushless DC (BLDC) Motor and high temperature resolver were also tested and the feasibility of the designs was demonstrated by the extended operation of both devices under Venus-like condition. Further development of the BLDC motor and resolver continues and these devices will, ultimately, be integrated into the development of a high temperature sample acquisition scoop and high temperature joint (awarded SBIR Phase II in October, 2007). Both the SR and BLDC motors will undergo extensive testing at Venus temperature and pressure (TRL6) and are expected to be mission ready before the next New

  8. High-Temperature Capacitor Polymer Films

    NASA Astrophysics Data System (ADS)

    Tan, Daniel; Zhang, Lili; Chen, Qin; Irwin, Patricia

    2014-12-01

    Film capacitor technology has been under development for over half a century to meet various applications such as direct-current link capacitors for transportation, converters/inverters for power electronics, controls for deep well drilling of oil and gas, direct energy weapons for military use, and high-frequency coupling circuitry. The biaxially oriented polypropylene film capacitor remains the state-of-the-art technology; however, it is not able to meet increasing demand for high-temperature (>125°C) applications. A number of dielectric materials capable of operating at high temperatures (>140°C) have attracted investigation, and their modifications are being pursued to achieve higher volumetric efficiency as well. This paper highlights the status of polymer dielectric film development and its feasibility for capacitor applications. High-temperature polymers such as polyetherimide (PEI), polyimide, and polyetheretherketone were the focus of our studies. PEI film was found to be the preferred choice for high-temperature film capacitor development due to its thermal stability, dielectric properties, and scalability.

  9. A Highly Reversible Room-Temperature Sodium Metal Anode

    PubMed Central

    2015-01-01

    Owing to its low cost and high natural abundance, sodium metal is among the most promising anode materials for energy storage technologies beyond lithium ion batteries. However, room-temperature sodium metal anodes suffer from poor reversibility during long-term plating and stripping, mainly due to formation of nonuniform solid electrolyte interphase as well as dendritic growth of sodium metal. Herein we report for the first time that a simple liquid electrolyte, sodium hexafluorophosphate in glymes (mono-, di-, and tetraglyme), can enable highly reversible and nondendritic plating–stripping of sodium metal anodes at room temperature. High average Coulombic efficiencies of 99.9% were achieved over 300 plating–stripping cycles at 0.5 mA cm–2. The long-term reversibility was found to arise from the formation of a uniform, inorganic solid electrolyte interphase made of sodium oxide and sodium fluoride, which is highly impermeable to electrolyte solvent and conducive to nondendritic growth. As a proof of concept, we also demonstrate a room-temperature sodium–sulfur battery using this class of electrolytes, paving the way for the development of next-generation, sodium-based energy storage technologies. PMID:27163006

  10. High temperature experiment for accelerator inertial fusion

    SciTech Connect

    Lee, E.P.

    1985-05-01

    The High Temperature Experiment (HTE) is intended to produce temperatures of 50 to 100 eV in solid density targets driven by heavy ion beams from a multiple beam induction linac. The fundamental variables (particle species, energy, number of beamlets, current and pulse length) must be fixed to achieve the temperature at minimum cost, subject to criteria of technical feasibility and relevance to the development of a Fusion Driver. The conceptual design begins with an assumed (radiation-limited) target temperature and uses limitations due to particle range, beamlet perveance, and target disassembly to bound the allowable values of mass number (A) and energy (E). An accelerator model is then applied to determine the minimum length accelerator, which is a guide to total cost. The accelerator model takes into account limits on transportable charge, maximum gradient, core mass per linear meter, and head-to-tail momentum variation within a pulse.

  11. High-Temperature Shape Memory Polymers

    NASA Technical Reports Server (NTRS)

    Yoonessi, Mitra; Weiss, Robert A.

    2012-01-01

    physical conformation changes when exposed to an external stimulus, such as a change in temperature. Such materials have a permanent shape, but can be reshaped above a critical temperature and fixed into a temporary shape when cooled under stress to below the critical temperature. When reheated above the critical temperature (Tc, also sometimes called the triggering or switching temperature), the materials revert to the permanent shape. The current innovation involves a chemically treated (sulfonated, carboxylated, phosphonated, or other polar function group), high-temperature, semicrystalline thermoplastic poly(ether ether ketone) (Tg .140 C, Tm = 340 C) mix containing organometallic complexes (Zn++, Li+, or other metal, ammonium, or phosphonium salts), or high-temperature ionic liquids (e.g. hexafluorosilicate salt with 1-propyl-3- methyl imidazolium, Tm = 210 C) to form a network where dipolar or ionic interactions between the polymer and the low-molecular-weight or inorganic compound forms a complex that provides a physical crosslink. Hereafter, these compounds will be referred to as "additives". The polymer is semicrystalline, and the high-melt-point crystals provide a temporary crosslink that acts as a permanent crosslink just so long as the melting temperature is not exceeded. In this example case, the melting point is .340 C, and the shape memory critical temperature is between 150 and 250 C. PEEK is an engineering thermoplastic with a high Young fs modulus, nominally 3.6 GPa. An important aspect of the invention is the control of the PEEK functionalization (in this example, the sulfonation degree), and the thermal properties (i.e. melting point) of the additive, which determines the switching temperature. Because the compound is thermoplastic, it can be formed into the "permanent" shape by conventional plastics processing operations. In addition, the compound may be covalently cross - linked after forming the permanent shape by S-PEEK by applying ionizing

  12. Research at Very High Pressures and High Temperatures

    ERIC Educational Resources Information Center

    Bundy, Francis P.

    1977-01-01

    Reviews research and apparatus utilized in the study of the states and characteristics of materials at very high temperatures and pressures. Includes three examples of the research being conducted. (SL)

  13. Bimodular high temperature planar oxygen gas sensor.

    PubMed

    Sun, Xiangcheng; Liu, Yixin; Gao, Haiyong; Gao, Pu-Xian; Lei, Yu

    2014-01-01

    A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs) thin film coated yttria-stabilized zirconia (YSZ) substrate. The thin film was prepared by radio frequency (r.f.) magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO NPs film was characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). X-ray diffraction (XRD) patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500, 600, and 800°C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF) output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors. PMID:25191652

  14. Bimodular high temperature planar oxygen gas sensor

    PubMed Central

    Sun, Xiangcheng; Liu, Yixin; Gao, Haiyong; Gao, Pu-Xian; Lei, Yu

    2014-01-01

    A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs) thin film coated yttria-stabilized zirconia (YSZ) substrate. The thin film was prepared by radio frequency (r.f.) magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO NPs film was characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). X-ray diffraction (XRD) patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500, 600, and 800°C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF) output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors. PMID:25191652

  15. High Summer Temperatures and Mortality in Estonia

    PubMed Central

    Oudin Åström, Daniel; Åström, Christofer; Rekker, Kaidi; Indermitte, Ene; Orru, Hans

    2016-01-01

    Background On-going climate change is predicted to result in a growing number of extreme weather events—such as heat waves—throughout Europe. The effect of high temperatures and heat waves are already having an important impact on public health in terms of increased mortality, but studies from an Estonian setting are almost entirely missing. We investigated mortality in relation to high summer temperatures and the time course of mortality in a coastal and inland region of Estonia. Methods We collected daily mortality data and daily maximum temperature for a coastal and an inland region of Estonia. We applied a distributed lag non-linear model to investigate heat related mortality and the time course of mortality in Estonia. Results We found an immediate increase in mortality associated with temperatures exceeding the 75th percentile of summer maximum temperatures, corresponding to approximately 23°C. This increase lasted for a couple of days in both regions. The total effect of elevated temperatures was not lessened by significant mortality displacement. Discussion We observed significantly increased mortality in Estonia, both on a country level as well as for a coastal region and an inland region with a more continental climate. Heat related mortality was higher in the inland region as compared to the coastal region, however, no statistically significant differences were observed. The lower risks in coastal areas could be due to lower maximum temperatures and cooling effects of the sea, but also better socioeconomic condition. Our results suggest that region specific estimates of the impacts of temperature extremes on mortality are needed. PMID:27167851

  16. NOSD-1000, the high-temperature nitrous oxide spectroscopic databank

    NASA Astrophysics Data System (ADS)

    Tashkun, S. A.; Perevalov, V. I.; Lavrentieva, N. N.

    2016-07-01

    We present a high-temperature version, NOSD-1000, of the nitrous oxide spectroscopic databank. The databank contains the line parameters (positions, intensities, air- and self-broadened half-widths and coefficients of temperature dependence of air- and self-broadened half-widths) of the most abundant isotopologue 14N216O of the nitrous oxide molecule. The reference temperature is Tref=1000 K and the intensity cutoff is Icut=10-25 cm-1/(molecule cm-2). More than 1.4 million lines covering the 260-8310 cm-1 spectral range are included in NOSD-1000. The databank has been generated within the framework of the method of effective operators and based on the global fittings of spectroscopic parameters (parameters of the effective Hamiltonian and effective dipole moment operators) to observed data collected from the literature. Line-by-line simulation of a medium-resolution high-temperature (T=873 K) spectrum has been performed in order to validate the databank. NOSD-1000 is freely accessible via the Internet.

  17. Thermal Conductivity of Complex Materials at High Temperatures and Pressures

    NASA Astrophysics Data System (ADS)

    Brown, J. M.; Xu, Y.; Harrell, M.; Shankland, T. J.

    2004-12-01

    Measurements of lattice thermal diffusivity have been obtained on (Mg0.9Fe0.1)2SiO4 olivine, its high-pressure polymorphs, and of (Mg0.9Fe0.1)SiO3 enstatite at conditions of temperature and pressure. We used two independent techniques: Impulsive Stimulated Light Scattering to 5 GPa and 1273 K and the Ångström method on cylindrical samples in a multianvil apparatus to 20 GPa and 1373 K. Lattice thermal conductivities were calculated from heat capacities and equations of state. Conductivities are consistent with previous results obtained at 1 atm. In olivines conductivity increases at each phase transition from olivine to spinel structures (corresponding to velocity discontinuities at depths of 410 and 520 km in the Earth). Of greatest significance is the fact that for each of these phases, lattice conductivity closely follows a T-1/2 dependence on temperature T, a prediction of Klemens (1960) for materials containing abundant lattice defects. If such a dependence applies to other silicates and complex crystals, there should be a useful way to estimate conductivities at high temperatures from room temperature measurements.

  18. Thermal Conductivity of Complex Materials at High Temperatures and Pressures

    NASA Astrophysics Data System (ADS)

    Brown, J. Michael; Xu, Yousheng; Harrell, Michael D.; Shankland, Thomas

    2004-03-01

    This paper presents measurements of lattice thermal diffusivity on (Mg_0.9Fe_0.1)_2SiO4 olivine, its high-pressure polymorphs, and of (Mg_0.9Fe_0.1)SiO3 enstatite at conditions of temperature and pressure. We used two independent techniques: impulsive stimulated light scattering to 5 GPa and 1273 K and the Ångström method on cylindrical samples in a multianvil apparatus to 20 GPa and 1373 K. Lattice thermal conductivities were calculated from heat capacities and equations of state. Conductivities are consistent with previous results obtained at 1 atm. In olivines conductivity increases at each phase transition from olivine to spinel structures (corresponding to velocity discontinuities at depths of 410 and 520 km in the Earth). Of greatest significance is the fact that for each of these phases, lattice conductivity closely follows a T-1/2 dependence on temperature T, a prediction of Klemens (1960) for materials containing abundant lattice defects. If such a dependence applies to other silicates and complex crystals, there should be a useful way to estimate conductivities at high temperatures from room temperature measurements.

  19. High-Temperature Adhesive Strain Gage Developed

    NASA Technical Reports Server (NTRS)

    Pereira, J. Michael; Roberts, Gary D.

    1997-01-01

    Researchers at the NASA Lewis Research Center have developed a unique strain gage and adhesive system for measuring the mechanical properties of polymers and polymer composites at elevated temperatures. This system overcomes some of the problems encountered in using commercial strain gages and adhesives. For example, typical commercial strain gage adhesives require a postcure at temperatures substantially higher than the maximum test temperature. The exposure of the specimen to this temperature may affect subsequent results, and in some cases may be higher than the glass-transition temperature of the polymer. In addition, although typical commercial strain gages can be used for short times at temperatures up to 370 C, their long-term use is limited to 230 C. This precludes their use for testing some high-temperature polyimides near their maximum temperature capability. Lewis' strain gage and adhesive system consists of a nonencapsulated, unbacked gage grid that is bonded directly to the polymer after the specimen has been cured but prior to the normal postcure cycle. The gage is applied with an adhesive specially formulated to cure under the specimen postcure conditions. Special handling, mounting, and electrical connection procedures were developed, and a fixture was designed to calibrate each strain gage after it was applied to a specimen. A variety of tests was conducted to determine the performance characteristics of the gages at elevated temperatures on PMR-15 neat resin and titanium specimens. For these tests, which included static tension, thermal exposure, and creep tests, the gage and adhesive system performed within normal strain gage specifications at 315 C. An example of the performance characteristics of the gage can be seen in the figure, which compares the strain gage measurement on a polyimide specimen at 315 C with an extensometer measurement.

  20. Two High-Temperature Foil Journal Bearings

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    2006-01-01

    An enlarged, high-temperature-compliant foil bearing has been built and tested to demonstrate the feasibility of such bearings for use in aircraft gas turbine engines. Foil bearings are attractive for use in some machines in which (1) speeds of rotation, temperatures, or both exceed maximum allowable values for rolling-element bearings; (2) conventional lubricants decompose at high operating temperatures; and/or (3) it is necessary or desirable not to rely on conventional lubrication systems. In a foil bearing, the lubricant is the working fluid (e.g., air or a mixture of combustion gases) in the space between the journal and the shaft in the machine in which the bearing is installed.

  1. Gravimeter using high-temperature superconductor bearing.

    SciTech Connect

    Hull, J. R.

    1998-09-11

    We have developed a sensitive gravimeter concept that uses an extremely low-friction bearing based on a permanent magnet (PM) levitated over a high-temperature superconductor (HTS). A mass is attached to the PM by means of a cantilevered beam, and the combination of PM and HTS forms a bearing platform that has low resistance to rotational motion but high resistance to horizontal, vertical, or tilting motion. The combination acts as a low-loss torsional pendulum that can be operated in any orientation. Gravity acts on the cantilevered beam and attached mass, accelerating them. Variations in gravity can be detected by time-of-flight acceleration, or by a control coil or electrode that would keep the mass stationary. Calculations suggest that the HTS gravimeter would be as sensitive as present-day superconducting gravimeters that need cooling to liquid helium temperatures, but the HTS gravimeter needs cooling only to liquid nitrogen temperatures.

  2. High Temperature Materials Interim Data Qualification Report

    SciTech Connect

    Nancy Lybeck

    2010-08-01

    ABSTRACT Projects for the very high temperature reactor (VHTR) Technology Development Office provide data in support of Nuclear Regulatory Commission licensing of the VHTR. Fuel and materials to be used in the reactor are tested and characterized to quantify performance in high temperature and high fluence environments. The VHTR program has established the NGNP Data Management and Analysis System (NDMAS) to ensure that VHTR data are qualified for use, stored in a readily accessible electronic form, and analyzed to extract useful results. This document focuses on the first NDMAS objective. It describes the High Temperature Materials characterization data stream, the processing of these data within NDMAS, and reports the interim FY2010 qualification status of the data. Data qualification activities within NDMAS for specific types of data are determined by the data qualification category assigned by the data generator. The High Temperature Materials data are being collected under NQA-1 guidelines, and will be qualified data. For NQA-1 qualified data, the qualification activities include: (1) capture testing, to confirm that the data stored within NDMAS are identical to the raw data supplied, (2) accuracy testing to confirm that the data are an accurate representation of the system or object being measured, and (3) documenting that the data were collected under an NQA-1 or equivalent Quality Assurance program. Currently, data from two test series within the High Temperature Materials data stream have been entered into the NDMAS vault: 1. Tensile Tests for Sm (i.e., Allowable Stress) Confirmatory Testing – 1,403,994 records have been inserted into the NDMAS database. Capture testing is in process. 2. Creep-Fatigue Testing to Support Determination of Creep-Fatigue Interaction Diagram – 918,854 records have been processed and inserted into the NDMAS database. Capture testing is in process.

  3. High pressure and high temperature behaviour of ZnO

    SciTech Connect

    Thakar, Nilesh A.; Bhatt, Apoorva D.; Pandya, Tushar C.

    2014-04-24

    The thermodynamic properties with the wurtzite (B4) and rocksalt (B1) phases of ZnO under high pressures and high temperatures have been investigated using Tait's Equation of state (EOS). The effects of pressures and temperatures on thermodynamic properties such as bulk modulus, thermal expansivity and thermal pressure are explored for both two structures. It is found that ZnO material gradually softens with increase of temperature while it hardens with the increment of the pressure. Our predicted results of thermodynamics properties for both the phases of ZnO are in overall agreement with the available data in the literature.

  4. Enamel for high-temperature superalloys

    NASA Technical Reports Server (NTRS)

    Levin, H.; Lent, W. E.

    1977-01-01

    Desired optical and high temperature enamel properties are obtained with glasses prepared from the system Li2O-ZrO2-nSiO2. Molar compositions range from n=4 to n=1.3, to which are added minor amounts in varying combinations of alumina, alkali fluorides, boric oxide, alkali oxides, and akaline earth oxides.

  5. 10.3 High-temperature Instrumentation

    NASA Technical Reports Server (NTRS)

    Piazza, Anthony

    2008-01-01

    This viewgraph presentation describes high temperature instrumentation development from 1960-1970, 1980-1990 and 2000-present. The contents include: 1) Background; 2) Objective; 3) Application and Sensor; 4) Attachment Techniques; 5) Evaluation/Characterization Testing; and 6) Future testing.

  6. Progress in advanced high temperature materials technology

    NASA Technical Reports Server (NTRS)

    Freche, J. C.; Ault, G. M.

    1976-01-01

    Significant progress has recently been made in many high temperature material categories pertinent to such applications by the industrial community. These include metal matrix composites, superalloys, directionally solidified eutectics, coatings, and ceramics. Each of these material categories is reviewed and the current state-of-the-art identified, including some assessment, when appropriate, of progress, problems, and future directions.

  7. High temperature pressure coupled ultrasonic waveguide

    DOEpatents

    Caines, Michael J.

    1983-01-01

    A pressure coupled ultrasonic waveguide is provided to which one end may be attached a transducer and at the other end a high temperature material for continuous ultrasonic testing of the material. The ultrasonic signal is coupled from the waveguide into the material through a thin, dry copper foil.

  8. Lightweight High-Temperature Thermal Insulation

    NASA Technical Reports Server (NTRS)

    Wagner, W. R.; Fasheh, J. I.

    1985-01-01

    Fine Ni/Cr fibers sintered into corrosion-resistant, fireproof batt. Possible applications include stoves, furnaces, safes, fire clothing, draperies in public buildings, wall firebreaks, airplane walls, and jetengine components. New insulation takes advantage of some of same properties of nickel/chromium alloy useful in heating elements in toasters, namely, corrosion and oxidation resistance even at high temperatures.

  9. Space applications of high temperature superconductivity technology

    NASA Technical Reports Server (NTRS)

    Connolly, D. J.; Aron, P. R.; Leonard, R. F.; Wintucky, E. G.

    1991-01-01

    A review is presented of the present status of high temperature superconductivity (HTS) technology and related areas of potential space application. Attention is given to areas of application that include microwave communications, cryogenic systems, remote sensing, and space propulsion and power. Consideration is given to HTS phase shifters, miniaturization of microwave filters, far-IR bolometers, and magnetic refrigeration using flux compression.

  10. Improved high-temperature silicide coatings

    NASA Technical Reports Server (NTRS)

    Klopp, W. D.; Stephens, J. R.; Stetson, A. R.; Wimber, R. T.

    1969-01-01

    Special technique for applying silicide coatings to refractory metal alloys improves their high-temperature protective capability. Refractory metal powders mixed with a baked-out organic binder and sintered in a vacuum produces a porous alloy layer on the surface. Exposing the layer to hot silicon converts it to a silicide.

  11. High-temperature corrosion in halogen environments

    SciTech Connect

    McNallan, M. )

    1994-09-01

    Halogen contaminants, particularly chlorine and fluorine, cause accelerated corrosion in such high-temperature systems as waste incinerators and waste heat recuperators on metallurgical furnaces. The mechanisms by which these phenomena occur are reviewed and discussed with the goal of identifying appropriate corrosion control strategies for materials that operate in these environments.

  12. High temperature oxidation resistant cermet compositions

    NASA Technical Reports Server (NTRS)

    Phillips, W. M. (Inventor)

    1976-01-01

    Cermet compositions are designed to provide high temperature resistant refractory coatings on stainless steel or molybdenum substrates. A ceramic mixture of chromium oxide and aluminum oxide form a coating of chromium oxide as an oxidation barrier around the metal particles, to provide oxidation resistance for the metal particles.

  13. High Temperature Langasite SAW Oxygen Sensor

    SciTech Connect

    Zheng, Peng; Chin, Tao-Lun; Greve, David; Oppenheim, Irving; Malone, Vanessa; Cao, Limin

    2011-08-01

    High-temperature langasite SAW oxygen sensors using sputtered ZnO as a resistive gas-sensing layer were fabricated and tested. Sensitivity to oxygen gas was observed between 500°C to 700°C, with a sensitivity peak at about 625°C, consistent with the theoretical predictions of the acoustoelectric effect.

  14. High temperature well bore cement slurry

    SciTech Connect

    Nahm, J.J.W.; Vinegar, H.J.; Karanikas, J.M.; Wyant, R.E.

    1993-07-13

    A low density well bore cement slurry composition is described suitable for cementing well bores with high reservoir temperatures comprising: (a) a high alumina cement in an amount of about 40 pounds per barrel of slurry or greater: (b) graphite in an amount greater than about one quarter, by volume, of the solids in the cement slurry; and (c) and a carrier fluid comprising drilling mud.

  15. Direct mutation analysis by high-throughput sequencing: from germline to low-abundant, somatic variants

    PubMed Central

    Gundry, Michael; Vijg, Jan

    2011-01-01

    DNA mutations are the source of genetic variation within populations. The majority of mutations with observable effects are deleterious. In humans mutations in the germ line can cause genetic disease. In somatic cells multiple rounds of mutations and selection lead to cancer. The study of genetic variation has progressed rapidly since the completion of the draft sequence of the human genome. Recent advances in sequencing technology, most importantly the introduction of massively parallel sequencing (MPS), have resulted in more than a hundred-fold reduction in the time and cost required for sequencing nucleic acids. These improvements have greatly expanded the use of sequencing as a practical tool for mutation analysis. While in the past the high cost of sequencing limited mutation analysis to selectable markers or small forward mutation targets assumed to be representative for the genome overall, current platforms allow whole genome sequencing for less than $5,000. This has already given rise to direct estimates of germline mutation rates in multiple organisms including humans by comparing whole genome sequences between parents and offspring. Here we present a brief history of the field of mutation research, with a focus on classical tools for the measurement of mutation rates. We then review MPS, how it is currently applied and the new insight into human and animal mutation frequencies and spectra that has been obtained from whole genome sequencing. While great progress has been made, we note that the single most important limitation of current MPS approaches for mutation analysis is the inability to address low-abundance mutations that turn somatic tissues into mosaics of cells. Such mutations are at the basis of intra-tumor heterogeneity, with important implications for clinical diagnosis, and could also contribute to somatic diseases other than cancer, including aging. Some possible approaches to gain access to low-abundance mutations are discussed, with a

  16. Microbial Diversity and Putative Diazotrophy in High- and Low-Microbial-Abundance Mediterranean Sponges.

    PubMed

    Ribes, Marta; Dziallas, Claudia; Coma, Rafel; Riemann, Lasse

    2015-09-01

    Microbial communities associated with marine sponges carry out nutrient transformations essential for benthic-pelagic coupling; however, knowledge about their composition and function is still sparse. We evaluated the richness and diversity of prokaryotic assemblages associated with three high-microbial-abundance (HMA) and three low-microbial-abundance (LMA) sympatric Mediterranean sponges to address their stability and uniqueness. Moreover, to examine functionality and because an imbalance between nitrogen ingestion and excretion has been observed for some of these species, we sequenced nitrogenase genes (nifH) and measured N2 fixation. The prokaryotic communities in the two sponge types did not differ in terms of richness, but the highest diversity was found in HMA sponges. Moreover, the discrete composition of the communities in the two sponge types relative to that in the surrounding seawater indicated that horizontal transmission and vertical transmission affect the microbiomes associated with the two sponge categories. nifH genes were found in all LMA species and sporadically in one HMA species, and about half of the nifH gene sequences were common between the different sponge species and were also found in the surrounding water, suggesting horizontal transmission. (15)N2-enriched incubations showed that N2 fixation was measurable in the water but was not associated with the sponges. Also, the analysis of the isotopic ratio of (15)N to (14)N in sponge tissue indicated that N2 fixation is not an important source of nitrogen in these Mediterranean sponges. Overall, our results suggest that compositional and functional features differ between the prokaryotic communities associated with HMA and LMA sponges, which may affect sponge ecology.

  17. Microbial Diversity and Putative Diazotrophy in High- and Low-Microbial-Abundance Mediterranean Sponges

    PubMed Central

    Coma, Rafel; Riemann, Lasse

    2015-01-01

    Microbial communities associated with marine sponges carry out nutrient transformations essential for benthic-pelagic coupling; however, knowledge about their composition and function is still sparse. We evaluated the richness and diversity of prokaryotic assemblages associated with three high-microbial-abundance (HMA) and three low-microbial-abundance (LMA) sympatric Mediterranean sponges to address their stability and uniqueness. Moreover, to examine functionality and because an imbalance between nitrogen ingestion and excretion has been observed for some of these species, we sequenced nitrogenase genes (nifH) and measured N2 fixation. The prokaryotic communities in the two sponge types did not differ in terms of richness, but the highest diversity was found in HMA sponges. Moreover, the discrete composition of the communities in the two sponge types relative to that in the surrounding seawater indicated that horizontal transmission and vertical transmission affect the microbiomes associated with the two sponge categories. nifH genes were found in all LMA species and sporadically in one HMA species, and about half of the nifH gene sequences were common between the different sponge species and were also found in the surrounding water, suggesting horizontal transmission. 15N2-enriched incubations showed that N2 fixation was measurable in the water but was not associated with the sponges. Also, the analysis of the isotopic ratio of 15N to 14N in sponge tissue indicated that N2 fixation is not an important source of nitrogen in these Mediterranean sponges. Overall, our results suggest that compositional and functional features differ between the prokaryotic communities associated with HMA and LMA sponges, which may affect sponge ecology. PMID:26070678

  18. Testing methods for using high-resolution satellite imagery to monitor polar bear abundance and distribution

    USGS Publications Warehouse

    LaRue, Michelle A.; Stapleton, Seth P.; Porter, Claire; Atkinson, Stephen N.; Atwood, Todd C.; Dyck, Markus; Lecomte, Nicolas

    2015-01-01

    High-resolution satellite imagery is a promising tool for providing coarse information about polar species abundance and distribution, but current applications are limited. With polar bears (Ursus maritimus), the technique has only proven effective on landscapes with little topographic relief that are devoid of snow and ice, and time-consuming manual review of imagery is required to identify bears. Here, we evaluated mechanisms to further develop methods for satellite imagery by examining data from Rowley Island, Canada. We attempted to automate and expedite detection via a supervised spectral classification and image differencing to expedite image review. We also assessed what proportion of a region should be sampled to obtain reliable estimates of density and abundance. Although the spectral signature of polar bears differed from nontarget objects, these differences were insufficient to yield useful results via a supervised classification process. Conversely, automated image differencing—or subtracting one image from another—correctly identified nearly 90% of polar bear locations. This technique, however, also yielded false positives, suggesting that manual review will still be required to confirm polar bear locations. On Rowley Island, bear distribution approximated a Poisson distribution across a range of plot sizes, and resampling suggests that sampling >50% of the site facilitates reliable estimation of density (CV <15%). Satellite imagery may be an effective monitoring tool in certain areas, but large-scale applications remain limited because of the challenges in automation and the limited environments in which the method can be effectively applied. Improvements in resolution may expand opportunities for its future uses.

  19. Dietary flavonoid fisetin increases abundance of high-molecular-mass hyaluronan conferring resistance to prostate oncogenesis.

    PubMed

    Lall, Rahul K; Syed, Deeba N; Khan, Mohammad Imran; Adhami, Vaqar M; Gong, Yuansheng; Lucey, John A; Mukhtar, Hasan

    2016-09-01

    We and others have shown previously that fisetin, a plant flavonoid, has therapeutic potential against many cancer types. Here, we examined the probable mechanism of its action in prostate cancer (PCa) using a global metabolomics approach. HPLC-ESI-MS analysis of tumor xenografts from fisetin-treated animals identified several metabolic targets with hyaluronan (HA) as the most affected. Efficacy of fisetin on HA was then evaluated in vitro and also in vivo in the transgenic TRAMP mouse model of PCa. Size exclusion chromatography-multiangle laser light scattering (SEC-MALS) was performed to analyze the molar mass (Mw) distribution of HA. Fisetin treatment downregulated intracellular and secreted HA levels both in vitro and in vivo Fisetin inhibited HA synthesis and degradation enzymes, which led to cessation of HA synthesis and also repressed the degradation of the available high-molecular-mass (HMM)-HA. SEC-MALS analysis of intact HA fragment size revealed that cells and animals have more abundance of HMM-HA and less of low-molecular-mass (LMM)-HA upon fisetin treatment. Elevated HA levels have been shown to be associated with disease progression in certain cancer types. Biological responses triggered by HA mainly depend on the HA polymer length where HMM-HA represses mitogenic signaling and has anti-inflammatory properties whereas LMM-HA promotes proliferation and inflammation. Similarly, Mw analysis of secreted HA fragment size revealed less HMM-HA is secreted that allowed more HMM-HA to be retained within the cells and tissues. Our findings establish that fisetin is an effective, non-toxic, potent HA synthesis inhibitor, which increases abundance of antiangiogenic HMM-HA and could be used for the management of PCa.

  20. Dietary flavonoid fisetin increases abundance of high-molecular-mass hyaluronan conferring resistance to prostate oncogenesis.

    PubMed

    Lall, Rahul K; Syed, Deeba N; Khan, Mohammad Imran; Adhami, Vaqar M; Gong, Yuansheng; Lucey, John A; Mukhtar, Hasan

    2016-09-01

    We and others have shown previously that fisetin, a plant flavonoid, has therapeutic potential against many cancer types. Here, we examined the probable mechanism of its action in prostate cancer (PCa) using a global metabolomics approach. HPLC-ESI-MS analysis of tumor xenografts from fisetin-treated animals identified several metabolic targets with hyaluronan (HA) as the most affected. Efficacy of fisetin on HA was then evaluated in vitro and also in vivo in the transgenic TRAMP mouse model of PCa. Size exclusion chromatography-multiangle laser light scattering (SEC-MALS) was performed to analyze the molar mass (Mw) distribution of HA. Fisetin treatment downregulated intracellular and secreted HA levels both in vitro and in vivo Fisetin inhibited HA synthesis and degradation enzymes, which led to cessation of HA synthesis and also repressed the degradation of the available high-molecular-mass (HMM)-HA. SEC-MALS analysis of intact HA fragment size revealed that cells and animals have more abundance of HMM-HA and less of low-molecular-mass (LMM)-HA upon fisetin treatment. Elevated HA levels have been shown to be associated with disease progression in certain cancer types. Biological responses triggered by HA mainly depend on the HA polymer length where HMM-HA represses mitogenic signaling and has anti-inflammatory properties whereas LMM-HA promotes proliferation and inflammation. Similarly, Mw analysis of secreted HA fragment size revealed less HMM-HA is secreted that allowed more HMM-HA to be retained within the cells and tissues. Our findings establish that fisetin is an effective, non-toxic, potent HA synthesis inhibitor, which increases abundance of antiangiogenic HMM-HA and could be used for the management of PCa. PMID:27335141

  1. Genome-wide detection of high abundance N6-methyladenosine sites by microarray

    PubMed Central

    Li, Yue; Wang, Yang; Zhang, Zhaolei; Zamudio, Alicia Viridiana; Zhao, Jing Crystal

    2015-01-01

    N6-methyladenosine (m6A), the most abundant internal RNA modification, functions in diverse biological processes, including regulation of embryonic stem cell self-renewal and differentiation. As yet, methods to detect m6A in the transcriptome rely on the availability and quality of an m6A antibody and are often associated with a high rate of false positives. Here, based on our observation that m6A interferes with A–T/U pairing, we report a microarray-based technology to map m6A sites in mouse embryonic stem cells. We identified 72 unbiased sites exhibiting high m6A levels from 66 PolyA RNAs. Bioinformatics analyses suggest identified sites are enriched on developmental regulators and may in some contexts modulate microRNA/mRNA interactions. Overall, we have developed microarray-based technology to capture highly enriched m6A sites in the mammalian transcriptome. This method provides an alternative means to identify m6A sites for certain applications. PMID:26092943

  2. Long-term Observations of Jovian Mid-Infrared Aurora, Hydrocarbon Abundances, and Temperature: Ground-based and Space-based Comparison and Preparation for Juno

    NASA Astrophysics Data System (ADS)

    Kostiuk, T.; Hewagama, T.; Livengood, T. A.; Fast, K. E.; Bjoraker, G. L.; Carlson, R. C.; Schmuelling, F.

    2015-12-01

    With Juno's approach to Jupiter in 2016 nearing, we report on long term measurements of Jupiter's thermal infrared aurora covering spectral and altitude regions that will complement Juno observational capabilities. Previously acquired spectral data from ground-based observatories as well as by Voyager IRIS and Cassini CIRS during Jupiter flybys will be investigated using current methods and capabilities. The thermal (mid-) IR aurora from Jupiter's polar regions, hydrocarbon abundances, and thermal structure retrieved from the ground and from space-based investigations will be compared and used to illustrate the different capabilities and complementarity of the measurement platforms. We report on the reexamination and re-analysis of hydrocarbon emission spectra from Jupiter obtained using ground-based ultra-high spectral resolution infrared heterodyne spectroscopy (IRHS) and Fourier transform spectroscopy (FTS) from Cassini CIRS during its flyby of Jupiter in 2000-2001 and Voyager IRIS data obtained during flybys in 1979. Measurements with IRHS have been made over 30 years, primarily of ethane near 12 micrometer wavelength. These measurements yield fully resolved individual spectral lines whose shape provides unique information on variability of temperature and abundance. CIRS and IRIS data at coarser spectral resolution provide extended spatial distributions covering a broad spectral region, including abundances and auroral response of hydrocarbon constituents in the 8-13 micrometer spectral region (ethane, methane, ethylene, and acetylene). Analysis shows detailed spatial variability of the primary hydrocarbons in northern latitudes. Temporal changes of the ethane line emission over three solar cycles and comparison of retrievals from ethane data taken contemporaneously during the Cassini flyby by both techniques will be compared and results discussed. From these analyses, the expectation is that the thermal IR auroral emission may be low during the Juno tour at

  3. Urania vapor composition at very high temperatures

    SciTech Connect

    Pflieger, Rachel; Colle, Jean-Yves; Iosilevskiy, Igor; Sheindlin, Michael

    2011-02-01

    Due to the chemically unstable nature of uranium dioxide its vapor composition at very high temperatures is, presently, not sufficiently studied though more experimental knowledge is needed for risk assessment of nuclear reactors. We used laser vaporization coupled to mass spectrometry of the produced vapor to study urania vapor composition at temperatures in the vicinity of its melting point and higher. The very good agreement between measured melting and freezing temperatures and between partial pressures measured on the temperature increase and decrease indicated that the change in stoichiometry during laser heating was very limited. The evolutions with temperature (in the range 2800-3400 K) of the partial pressures of the main vapor species (UO{sub 2}, UO{sub 3}, and UO{sub 2}{sup +}) were compared with theoretically predicted evolutions for equilibrium noncongruent gas-liquid and gas-solid phase coexistences and showed very good agreement. The measured main relative partial pressure ratios around 3300 K all agree with calculated values for total equilibrium between condensed and vapor phases. It is the first time the three main partial pressure ratios above stoichiometric liquid urania have been measured at the same temperature under conditions close to equilibrium noncongruent gas-liquid phase coexistence.

  4. High temperature annealing of ion irradiated tungsten

    SciTech Connect

    Ferroni, Francesco; Yi, Xiaoou; Fitzgerald, Steven P.; Edmondson, Philip D.; Roberts, Steve G.

    2015-03-21

    In this study, transmission electron microscopy of high temperature annealing of pure tungsten irradiated by self-ions was conducted to elucidate microstructural and defect evolution in temperature ranges relevant to fusion reactor applications (500–1200°C). Bulk isochronal and isothermal annealing of ion irradiated pure tungsten (2 MeV W+ ions, 500°C, 1014 W+/cm2) with temperatures of 800, 950, 1100 and 1400°C, from 0.5 to 8 h, was followed by ex situ characterization of defect size, number density, Burgers vector and nature. Loops with diameters larger than 2–3 nm were considered for detailed analysis, among which all loops had View the MathML source and were predominantly of interstitial nature. In situ annealing experiments from 300 up to 1200°C were also carried out, including dynamic temperature ramp-ups. These confirmed an acceleration of loop loss above 900°C. At different temperatures within this range, dislocations exhibited behaviour such as initial isolated loop hopping followed by large-scale rearrangements into loop chains, coalescence and finally line–loop interactions and widespread absorption by free-surfaces at increasing temperatures. An activation energy for the annealing of dislocation length was obtained, finding Ea=1.34±0.2 eV for the 700–1100°C range.

  5. High temperature annealing of ion irradiated tungsten

    DOE PAGES

    Ferroni, Francesco; Yi, Xiaoou; Arakawa, Kazuto; Fitzgerald, Steven P.; Edmondson, Philip D.; Roberts, Steve G.

    2015-03-21

    In this study, transmission electron microscopy of high temperature annealing of pure tungsten irradiated by self-ions was conducted to elucidate microstructural and defect evolution in temperature ranges relevant to fusion reactor applications (500–1200°C). Bulk isochronal and isothermal annealing of ion irradiated pure tungsten (2 MeV W+ ions, 500°C, 1014 W+/cm2) with temperatures of 800, 950, 1100 and 1400°C, from 0.5 to 8 h, was followed by ex situ characterization of defect size, number density, Burgers vector and nature. Loops with diameters larger than 2–3 nm were considered for detailed analysis, among which all loops had View the MathML source andmore » were predominantly of interstitial nature. In situ annealing experiments from 300 up to 1200°C were also carried out, including dynamic temperature ramp-ups. These confirmed an acceleration of loop loss above 900°C. At different temperatures within this range, dislocations exhibited behaviour such as initial isolated loop hopping followed by large-scale rearrangements into loop chains, coalescence and finally line–loop interactions and widespread absorption by free-surfaces at increasing temperatures. An activation energy for the annealing of dislocation length was obtained, finding Ea=1.34±0.2 eV for the 700–1100°C range.« less

  6. High temperature furnace modeling and performance verifications

    NASA Technical Reports Server (NTRS)

    Smith, James E., Jr.

    1992-01-01

    Analytical, numerical, and experimental studies were performed on two classes of high temperature materials processing sources for their potential use as directional solidification furnaces. The research concentrated on a commercially available high temperature furnace using a zirconia ceramic tube as the heating element and an Arc Furnace based on a tube welder. The first objective was to assemble the zirconia furnace and construct parts needed to successfully perform experiments. The 2nd objective was to evaluate the zirconia furnace performance as a directional solidification furnace element. The 3rd objective was to establish a data base on materials used in the furnace construction, with particular emphasis on emissivities, transmissivities, and absorptivities as functions of wavelength and temperature. A 1-D and 2-D spectral radiation heat transfer model was developed for comparison with standard modeling techniques, and were used to predict wall and crucible temperatures. The 4th objective addressed the development of a SINDA model for the Arc Furnace and was used to design sample holders and to estimate cooling media temperatures for the steady state operation of the furnace. And, the 5th objective addressed the initial performance evaluation of the Arc Furnace and associated equipment for directional solidification. Results of these objectives are presented.

  7. High temperature intermetallic binders for HVOF carbides

    SciTech Connect

    Shaw, K.G.; Gruninger, M.F.; Jarosinski, W.J.

    1994-12-31

    Gas turbines technology has a long history of employing the desirable high temperature physical attributes of ceramic-metallic (cermet) materials. The most commonly used coatings incorporate combinations of WC-Co and Cr{sub 3}C{sub 2}-NiCr, which have also been successfully utilized in other non-turbine coating applications. Increased turbine operating temperatures and other high temperature service conditions have made apparent the attractive notion of increasing the temperature capability and corrosion resistance of these coatings. In this study the intermetallic binder NiAl has been used to replace the cobalt and NiCr constituents of conventional WC and Cr{sub 3}C{sub 2} cermet powders. The composite carbide thermal spray powders were fabricated for use in the HVOF coating process. The structure of HVOF deposited NiAl-carbide coatings are compared directly to the more familiar WC-Co and Cr{sub 3}C{sub 2}-NiCr coatings using X-ray diffraction, back-scattered electron imaging (BEI) and electron dispersive spectroscopy (EDS). Hardness variations with temperature are reported and compared between the NiAl and Co/NiCr binders.

  8. Advanced high temperature thermoelectrics for space power

    NASA Technical Reports Server (NTRS)

    Lockwood, A.; Ewell, R.; Wood, C.

    1981-01-01

    Preliminary results from a spacecraft system study show that an optimum hot junction temperature is in the range of 1500 K for advanced nuclear reactor technology combined with thermoelectric conversion. Advanced silicon germanium thermoelectric conversion is feasible if hot junction temperatures can be raised roughly 100 C or if gallium phosphide can be used to improve the figure of merit, but the performance is marginal. Two new classes of refractory materials, rare earth sulfides and boron-carbon alloys, are being investigated to improve the specific weight of the generator system. Preliminary data on the sulfides have shown very high figures of merit over short temperature ranges. Both n- and p-type doping have been obtained. Pure boron-carbide may extrapolate to high figure of merit at temperatures well above 1500 K but not lower temperature; n-type conduction has been reported by others, but not yet observed in the JPL program. Inadvertant impurity doping may explain the divergence of results reported.

  9. High temperature superconductors applications in telecommunications

    NASA Technical Reports Server (NTRS)

    Kumar, A. Anil; Li, Jiang; Zhang, Ming Fang

    1995-01-01

    The purpose of this paper is twofold: (1) to discuss high temperature superconductors with specific reference to their employment in telecommunications applications; and (2) to discuss a few of the limitations of the normally employed two-fluid model. While the debate on the actual usage of high temperature superconductors in the design of electronic and telecommunications devices - obvious advantages versus practical difficulties - needs to be settled in the near future, it is of great interest to investigate the parameters and the assumptions that will be employed in such designs. This paper deals with the issue of providing the microwave design engineer with performance data for such superconducting waveguides. The values of conductivity and surface resistance, which are the primary determining factors of a waveguide performance, are computed based on the two-fluid model. A comparison between two models - a theoretical one in terms of microscopic parameters (termed Model A) and an experimental fit in terms of macroscopic parameters (termed Model B) - shows the limitations and the resulting ambiguities of the two-fluid model at high frequencies and at temperatures close to the transition temperature. The validity of the two-fluid model is then discussed. Our preliminary results show that the electrical transport description in the normal and superconducting phases as they are formulated in the two-fluid model needs to be modified to incorporate the new and special features of high temperature superconductors. Parameters describing the waveguide performance - conductivity, surface resistance and attenuation constant - will be computed. Potential applications in communications networks and large scale integrated circuits will be discussed. Some of the ongoing work will be reported. In particular, a brief proposal is made to investigate of the effects of electromagnetic interference and the concomitant notion of electromagnetic compatibility (EMI/EMC) of high T

  10. High temperature superconductors applications in telecommunications

    SciTech Connect

    Kumar, A.A.; Li, J.; Zhang, M.F.

    1994-12-31

    The purpose of this paper is twofold: to discuss high temperature superconductors with specific reference to their employment in telecommunications applications; and to discuss a few of the limitations of the normally employed two-fluid model. While the debate on the actual usage of high temperature superconductors in the design of electronic and telecommunications devices-obvious advantages versus practical difficulties-needs to be settled in the near future, it is of great interest to investigate the parameters and the assumptions that will be employed in such designs. This paper deals with the issue of providing the microwave design engineer with performance data for such superconducting waveguides. The values of conductivity and surface resistance, which are the primary determining factors of a waveguide performance, are computed based on the two-fluid model. A comparison between two models-a theoretical one in terms of microscopic parameters (termed Model A) and an experimental fit in terms of macroscopic parameters (termed Model B)-shows the limitations and the resulting ambiguities of the two-fluid model at high frequencies and at temperatures close to the transition temperature. The validity of the two-fluid model is then discussed. Our preliminary results show that the electrical transport description in the normal and superconducting phases as they are formulated in the two-fluid model needs to be modified to incorporate the new and special features of high temperature superconductors. Parameters describing the waveguide performance-conductivity, surface resistance and attenuation constant-will be computed. Potential applications in communications networks and large scale integrated circuits will be discussed. Some of the ongoing work will be reported. In particular, a brief proposal is made to investigate of the effects of electromagnetic interference and the concomitant notion of electromagnetic compatibility (EMI/EMC) of high T{sub c} superconductors.

  11. Operator manual: High temperature heat pump

    NASA Astrophysics Data System (ADS)

    Dyer, D. F.; Maples, G.; Burch, T. E.; Chancellor, P. D.

    1980-03-01

    Experimental data were obtained from operating a high temperature heat pump system. The use of methanol as a working fluid necessitated careful monitoring of refrigerant temperatures and pressures with chemical analysis performed on the working fluid during scheduled down time. Materials sent to vendors and quotes received concerning equipment (compressor, evaporator, condensor, air heater, dryer, two accumulator tanks, and three expansion valves) are discussed. The detailed design and pricing estimates are included. Additional information on layout and construction; start-up; testing; shut down; scheduled maintenance and inspection; safety precautions; control system; and trouble shooting is presented.

  12. Coal transformation under high-temperature catagenesis

    SciTech Connect

    Melenevsky, V.N.; Sokol, E.V.; Fomin, A.N.

    2006-07-01

    In this paper we consider products of natural pyrolysis of lignite, which resulted from the high-temperature spontaneous combustion of spoil heaps of the Chelyabinsk coal basin. These products were studied by pyrolysis, element and petrographic analyses, chromatomass spectrometry, and X-ray diffraction method. We have established that under reducing conditions, the degree of pyrogenic coal transformation and the composition of pyrolysis products vary greatly, from graphite-like phases to bitumens, and depend on the temperature and degree of the system openness.

  13. Fiber specklegram sensors sensitivities at high temperatures

    NASA Astrophysics Data System (ADS)

    Rodriguez-Cobo, L.; Lomer, M.; Lopez-Higuera, J. M.

    2015-09-01

    In this work, the sensitivity of Fiber Specklegram Sensors to high temperatures (up to 800ºC) have been studied. Two multimode silica fibers have been introduced into a tubular furnace while a HeNe laser source was launched into a fiber edge, projecting speckle patterns to a commercial webcam. A computer generated different heating and cooling sweeps while the specklegram evolution was recorded. The achieved results exhibit a remarkably linearity in FSS's sensitivity for temperatures under 800ºC, following the thermal expansion of fused silica.

  14. High-Temperature Behavior of Cellulose I

    SciTech Connect

    Matthews, James F.; Bergenstråhle, Malin; Beckham, Gregg T.; Himmel, Michael E.; Nimlos, Mark R.; Brady, John W.; Crowley, Michael F.

    2011-03-17

    We use molecular simulation to elucidate the structural behavior of small hydrated cellulose Iβ microfibrils heated to 227 °C (500 K) with two carbohydrate force fields. In contrast to the characteristic two-dimensional hydrogen-bonded layer sheets present in the cellulose Iβ crystal structure, we show that at high temperature a three-dimensional hydrogen bond network forms, made possible by hydroxymethyl groups changing conformation from trans–gauche (TG) to gauche–gauche (GG) in every second layer corresponding to “center” chains in cellulose Iβ and from TG to gauche–trans (GT) in the “origin” layer. The presence of a regular three-dimensional hydrogen bond network between neighboring sheets eliminates the possibility of twist, whereas two-dimensional hydrogen bonding allows for microfibril twist to occur. Structural features of this high-temperature phase as determined by molecular simulation may explain several experimental observations for which no detailed structural basis has been offered. This includes an explanation for the observed temperature and crystal size dependence for the extent of hydrogen/deuterium exchange, and diffraction patterns of cellulose at high temperature.

  15. The moon as a high temperature condensate

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.

    1972-01-01

    The accretion during condensation mechanism is used to explain the differences in composition of the terrestrial planets and the moon. Many of the properties of the moon, including the enrichment in Ca, Al, Ti, U, Th, Ba, Sr and the REE and the depletion in Fe, Rb, K, Na and other volatiles can be understood if the moon represents a high temperature condensate from the solar nebula. Thermodynamic calculations show that Ca, Al and Ti rich compounds condense first in a cooling nebula. The high temperature mineralogy is gehlenite, spinel perovskite, Ca-Al-rich pyroxenes and anorthite. The model is consistent with extensive early melting, shallow melting at 3 A.E. and with presently high speed internal temperatures. It is predicted that the outer 250 km is rich in plagioclase and FeO. The low iron content of the interior in this model raises the interior temperatures estimated from electrical conductivity by some 800 C. The lunar crust is 80 percent gabbroic anorthosite, 20 percent basalt and is about 250-270 km thick. The lunar mantle is probably composed of spinel, merwinite and diopside with a density of 3.4 g/cu cm.

  16. High temperature dynamic engine seal technology development

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M.; Dellacorte, Christopher; Machinchick, Michael; Mutharasan, Rajakkannu; Du, Guang-Wu; Ko, Frank; Sirocky, Paul J.; Miller, Jeffrey H.

    1992-01-01

    Combined cycle ramjet/scramjet engines being designed for advanced hypersonic vehicles, including the National Aerospace Plane (NASP), require innovative high temperature dynamic seals to seal the sliding interfaces of the articulated engine panels. New seals are required that will operate hot (1200 to 2000 F), seal pressures ranging from 0 to 100 psi, remain flexible to accommodate significant sidewall distortions, and resist abrasion over the engine's operational life. This report reviews the recent high temperature durability screening assessments of a new braided rope seal concept, braided of emerging high temperature materials, that shows promise of meeting many of the seal demands of hypersonic engines. The paper presents durability data for: (1) the fundamental seal building blocks, a range of candidate ceramic fiber tows; and for (2) braided rope seal subelements scrubbed under engine simulated sliding, temperature, and preload conditions. Seal material/architecture attributes and limitations are identified through the investigations performed. The paper summarizes the current seal technology development status and presents areas in which future work will be performed.

  17. Lightweight high-temperature fuel metering valves

    NASA Astrophysics Data System (ADS)

    Bennett, Joe

    AlliedSignal Fluid systems has provided fuel metering valve hardware to three aircraft engine manufacturers for evaluation. Two of the progams were Integrated High Performance Turbine Engine Technology (IHPTET) related. The third program was an IR&D effort. Bench tests and evaluation of all three valve designs have been completed, and one of the designs has actually been used for engine test. Engine testing of the other two valve designs is planned for the future. These three designs are similar, but each is intended to be usused in different system configurations, and each valve design offers unique features. The design approaches used for the three valve designs incorporate several new and innovative technologies, including high-temperature brushless dc motor actuators, low-pressure loss metering element design, fiber optic rotarty output position sensor, no-moving-parts oscillating jet flow meter, high-temperature RS (rapid solidification) aluminum alloy, high-temperature elastomeric seals, high-pressure shutoff capabilities, and closed loop electronic fuel flow metering.

  18. High temperature aircraft research furnace facilities

    NASA Technical Reports Server (NTRS)

    Smith, James E., Jr.; Cashon, John L.

    1992-01-01

    Focus is on the design, fabrication, and development of the High Temperature Aircraft Research Furnace Facilities (HTARFF). The HTARFF was developed to process electrically conductive materials with high melting points in a low gravity environment. The basic principle of operation is to accurately translate a high temperature arc-plasma gas front as it orbits around a cylindrical sample, thereby making it possible to precisely traverse the entire surface of a sample. The furnace utilizes the gas-tungsten-arc-welding (GTAW) process, also commonly referred to as Tungsten-Inert-Gas (TIG). The HTARFF was developed to further research efforts in the areas of directional solidification, float-zone processing, welding in a low-gravity environment, and segregation effects in metals. The furnace is intended for use aboard the NASA-JSC Reduced Gravity Program KC-135A Aircraft.

  19. High-Temperature Graphite/Phenolic Composite

    NASA Technical Reports Server (NTRS)

    Seal, Ellis C.; Bodepudi, Venu P.; Biggs, Robert W., Jr.; Cranston, John A.

    1995-01-01

    Graphite-fiber/phenolic-resin composite material retains relatively high strength and modulus of elasticity at temperatures as high as 1,000 degrees F. Costs only 5 to 20 percent as much as refractory materials. Fabrication composite includes curing process in which application of full autoclave pressure delayed until after phenolic resin gels. Curing process allows moisture to escape, so when composite subsequently heated in service, much less expansion of absorbed moisture and much less tendency toward delamination. Developed for nose cone of external fuel tank of Space Shuttle. Other potential aerospace applications for material include leading edges, parts of nozzles, parts of aircraft engines, and heat shields. Terrestrial and aerospace applications include structural firewalls and secondary structures in aircraft, spacecraft, and ships. Modified curing process adapted to composites of phenolic with other fiber reinforcements like glass or quartz. Useful as high-temperature circuit boards and electrical insulators.

  20. The metallurgy of high temperature alloys

    NASA Technical Reports Server (NTRS)

    Tien, J. K.; Purushothaman, S.

    1976-01-01

    Nickel-base, cobalt-base, and high nickel and chromium iron-base alloys are dissected, and their microstructural and chemical components are assessed with respect to the various functions expected of high temperature structural materials. These functions include the maintenance of mechanical integrity over the strain-rate spectrum from creep resistance through fatigue crack growth resistance, and such alloy stability expectations as microstructural coarsening resistance, phase instability resistance and oxidation and corrosion resistance. Special attention will be given to the perennial conflict and trade-off between strength, ductility and corrosion and oxidation resistance. The newest developments in the constitution of high temperature alloys will also be discussed, including aspects relating to materials conservation.

  1. Optically transparent high temperature shape memory polymers.

    PubMed

    Xiao, Xinli; Qiu, Xueying; Kong, Deyan; Zhang, Wenbo; Liu, Yanju; Leng, Jinsong

    2016-03-21

    Optically transparent shape memory polymers (SMPs) have potential in advanced optoelectronic and other common shape memory applications, and here optically transparent shape memory polyimide is reported for the first time. The polyimide possesses a glass transition temperature (Tg) of 171 °C, higher than the Tg of other transparent SMPs reported, and the influence of molecular structure on Tg is discussed. The 120 μm thick polyimide film exhibits transmittance higher than 81% in 450-800 nm, and the possible mechanism of its high transparency is analyzed, which will benefit further research on other transparent high temperature SMPs. The transparent polyimide showed excellent thermomechanical properties and shape memory performances, and retained high optical transparency after many shape memory cycles. PMID:26686222

  2. Effects of warm winter temperature on the abundance and gonotrophic activity of Culex (Diptera: Culicidae) in California.

    PubMed

    Reisen, William K; Thiemann, Tara; Barker, Christopher M; Lu, Helen; Carroll, Brian; Fang, Ying; Lothrop, Hugh D

    2010-03-01

    Culex tarsalis Coquillett, Cx. quinquefasciatus Say, and Cx. pipiens L. were collected during the warm winter of 2009 using dry ice-baited and gravid traps and walk-in red boxes positioned in desert, urban, and agricultural habitats in Riverside, Los Angeles, Kern, and Yolo Counties. Temperatures exceeded the preceding 50 yr averages in all locations for most of January, whereas rainfall was absent or below average. Abundance of Culex species in traps during January ranged from 83 to 671% of the prior 5 yr average in all locations. Few females collected resting were in diapause during January based on follicular measurements. Evidence for early season gonotrophic activity included the detection of freshly bloodfed, gravid, and parous females in resting collections, gravid oviposition site-seeking females in gravid female traps, and nulliparous and parous host-seeking females at dry ice-baited traps. Female Culex seemed to employ multiple overwintering strategies in California, including larval and adult quiescence, adult female diapause, and an intermediate situation with adult females collected with enlarged follicles, but without evident vitellogenesis. West Nile, St. Louis, or western equine encephalitis viruses were not detected in 198 pools of adults or 56 pools of adults reared from field-collected immatures collected during January and February 2009. Our preliminary data may provide insight into how climate change may extend the mosquito season in California. PMID:20380305

  3. Enabling Earth-Abundant Pyrite (FeS2) Semiconductor Nanostructures for High Performance Photovoltaic Devices

    SciTech Connect

    Jin, Song

    2014-11-18

    This project seeks to develop nanostructures of iron pyrite, an earth-abundant semiconductor, to enable their applications in high-performance photovoltaic (PV) devices. Growth of high purity iron pyrite nanostructures (nanowires, nanorods, and nanoplates), as well as iron pyrite thin films and single crystals, has been developed and their structures characterized. These structures have been fundamentally investigated to understand the origin of the low solar energy conversion efficiency of iron pyrite and various passivation strategies and doping approaches have been explored in order to improve it. By taking advantage of the high surface-to-bulk ratio in nanostructures and effective electrolyte gating, we fully characterized both the surface inversion and bulk electrical transport properties for the first time through electrolyte-gated Hall measurements of pyrite nanoplate devices and show that pyrite is n-type in the bulk and p-type near the surface due to strong inversion, which has important consequences to using nanocrystalline pyrite for efficient solar energy conversion. Furthermore, through a comprehensive investigation on n-type iron pyrite single crystals, we found the ionization of high-density bulk deep donor states, likely resulting from bulk sulfur vacancies, creates a non-constant charge distribution and a very narrow surface space charge region that limits the total barrier height, thus satisfactorily explains the limited photovoltage and poor photoconversion efficiency of iron pyrite single crystals. These findings suggest new ideas on how to improve single crystal pyrite and nanocrystalline or polycrystalline pyrite films to enable them for high performance solar applications.

  4. High Temperature Fluoride Salt Test Loop

    SciTech Connect

    Aaron, Adam M.; Cunningham, Richard Burns; Fugate, David L.; Holcomb, David Eugene; Kisner, Roger A.; Peretz, Fred J.; Robb, Kevin R.; Wilson, Dane F.; Yoder, Jr, Graydon L.

    2015-12-01

    Effective high-temperature thermal energy exchange and delivery at temperatures over 600°C has the potential of significant impact by reducing both the capital and operating cost of energy conversion and transport systems. It is one of the key technologies necessary for efficient hydrogen production and could potentially enhance efficiencies of high-temperature solar systems. Today, there are no standard commercially available high-performance heat transfer fluids above 600°C. High pressures associated with water and gaseous coolants (such as helium) at elevated temperatures impose limiting design conditions for the materials in most energy systems. Liquid salts offer high-temperature capabilities at low vapor pressures, good heat transport properties, and reasonable costs and are therefore leading candidate fluids for next-generation energy production. Liquid-fluoride-salt-cooled, graphite-moderated reactors, referred to as Fluoride Salt Reactors (FHRs), are specifically designed to exploit the excellent heat transfer properties of liquid fluoride salts while maximizing their thermal efficiency and minimizing cost. The FHR s outstanding heat transfer properties, combined with its fully passive safety, make this reactor the most technologically desirable nuclear power reactor class for next-generation energy production. Multiple FHR designs are presently being considered. These range from the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) [1] design originally developed by UC-Berkeley to the Small Advanced High-Temperature Reactor (SmAHTR) and the large scale FHR both being developed at ORNL [2]. The value of high-temperature, molten-salt-cooled reactors is also recognized internationally, and Czechoslovakia, France, India, and China all have salt-cooled reactor development under way. The liquid salt experiment presently being developed uses the PB-AHTR as its focus. One core design of the PB-AHTR features multiple 20 cm diameter, 3.2 m long fuel channels

  5. Gasification of high ash, high ash fusion temperature bituminous coals

    DOEpatents

    Liu, Guohai; Vimalchand, Pannalal; Peng, WanWang

    2015-11-13

    This invention relates to gasification of high ash bituminous coals that have high ash fusion temperatures. The ash content can be in 15 to 45 weight percent range and ash fusion temperatures can be in 1150.degree. C. to 1500.degree. C. range as well as in excess of 1500.degree. C. In a preferred embodiment, such coals are dealt with a two stage gasification process--a relatively low temperature primary gasification step in a circulating fluidized bed transport gasifier followed by a high temperature partial oxidation step of residual char carbon and small quantities of tar. The system to process such coals further includes an internally circulating fluidized bed to effectively cool the high temperature syngas with the aid of an inert media and without the syngas contacting the heat transfer surfaces. A cyclone downstream of the syngas cooler, operating at relatively low temperatures, effectively reduces loading to a dust filtration unit. Nearly dust- and tar-free syngas for chemicals production or power generation and with over 90%, and preferably over about 98%, overall carbon conversion can be achieved with the preferred process, apparatus and methods outlined in this invention.

  6. Strain sensing technology for high temperature applications

    NASA Technical Reports Server (NTRS)

    Williams, W. Dan

    1993-01-01

    This review discusses the status of strain sensing technology for high temperature applications. Technologies covered are those supported by NASA such as required for applications in hypersonic vehicles and engines, advanced subsonic engines, as well as material and structure development. The applications may be at temperatures of 540 C (1000 F) to temperatures in excess of 1400 C (2500 F). The most promising technologies at present are the resistance strain gage and remote sensing schemes. Resistance strain gages discussed include the BCL gage, the LaRC compensated gage, and the PdCr gage. Remote sensing schemes such as laser based speckle strain measurement, phase-shifling interferometry, and x-ray extensometry are discussed. Present status and limitations of these technologies are presented.

  7. Improved high-temperature resistant matrix resins

    NASA Technical Reports Server (NTRS)

    Green, H. E.; Chang, G. E.; Wright, W. F.; Ueda, K.; Orell, M. K.

    1989-01-01

    A study was performed with the objective of developing matrix resins that exhibit improved thermo-oxidative stability over state-of-the-art high temperature resins for use at temperatures up to 644 K (700 F) and air pressures up to 0.7 MPa (100 psia). The work was based upon a TRW discovered family of polyimides currently licensed to and marketed by Ethyl Corporation as EYMYD(R) resins. The approach investigated to provide improved thermo-oxidative properties was to use halogenated derivatives of the diamine, 2, 2-bis (4-(4-aminophenoxy)phenyl) hexafluoropropane (4-BDAF). Polyimide neat resins and Celion(R) 12,000 composites prepared from fluorine substituted 4-BDAF demonstrated unexpectedly lower glass transition temperatures (Tg) and thermo-oxidative stabilities than the baseline 4-BDAF/PMDA polymer.

  8. Compliant high temperature seals for dissimilar materials

    DOEpatents

    Rynders, Steven Walton; Minford, Eric; Tressler, Richard Ernest; Taylor, Dale M.

    2001-01-01

    A high temperature, gas-tight seal is formed by utilizing one or more compliant metallic toroidal ring sealing elements, where the applied pressure serves to activate the seal, thus improving the quality of the seal. The compliant nature of the sealing element compensates for differences in thermal expansion between the materials to be sealed, and is particularly useful in sealing a metallic member and a ceramic tube art elevated temperatures. The performance of the seal may be improved by coating the sealing element with a soft or flowable coating such as silver or gold and/or by backing the sealing element with a bed of fine powder. The material of the sealing element is chosen such that the element responds to stress elastically, even at elevated temperatures, permitting the seal to operate through multiple thermal cycles.

  9. Thermoelectric properties by high temperature annealing

    NASA Technical Reports Server (NTRS)

    Ren, Zhifeng (Inventor); Chen, Gang (Inventor); Kumar, Shankar (Inventor); Lee, Hohyun (Inventor)

    2009-01-01

    The present invention generally provides methods of improving thermoelectric properties of alloys by subjecting them to one or more high temperature annealing steps, performed at temperatures at which the alloys exhibit a mixed solid/liquid phase, followed by cooling steps. For example, in one aspect, such a method of the invention can include subjecting an alloy sample to a temperature that is sufficiently elevated to cause partial melting of at least some of the grains. The sample can then be cooled so as to solidify the melted grain portions such that each solidified grain portion exhibits an average chemical composition, characterized by a relative concentration of elements forming the alloy, that is different than that of the remainder of the grain.

  10. Opacification of high temperature fibrous insulation

    NASA Technical Reports Server (NTRS)

    Miller, W. C.; Collins, J. O.

    1984-01-01

    A study was conducted to determine the merits of adding particulate materials to silica fiber felts to increase their resistance to the passage of thermal radiation. Laboratory samples containing 5, 10, and 15 percent of chromium oxide, silicon carbide, and titanium dioxide were prepared and evaluated in accordance with ASTM C-518 thermal conductivity test method at 425 C (800 F) mean temperature. The titania particles averaging 3-4 micrometers in diameter were found to be the most effective. This was followed by a short plant run, in order to confirm the initial results on the laboratory samples. These samples were tested according to ASTM C-201 High Temperature Calorimeter from 93 C to 760 C (200 F to 1400 F) mean temperature. The ten percent by weight of titania resulted in an optimum effectiveness, and reduced the conductivity over 20% at 760 C (1400 F).

  11. Simulated Data for High Temperature Composite Design

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.; Abumeri, Galib H.

    2006-01-01

    The paper describes an effective formal method that can be used to simulate design properties for composites that is inclusive of all the effects that influence those properties. This effective simulation method is integrated computer codes that include composite micromechanics, composite macromechanics, laminate theory, structural analysis, and multi-factor interaction model. Demonstration of the method includes sample examples for static, thermal, and fracture reliability for a unidirectional metal matrix composite as well as rupture strength and fatigue strength for a high temperature super alloy. Typical results obtained for a unidirectional composite show that the thermal properties are more sensitive to internal local damage, the longitudinal properties degrade slowly with temperature, the transverse and shear properties degrade rapidly with temperature as do rupture strength and fatigue strength for super alloys.

  12. High temperature application of retrievable MWD systems

    SciTech Connect

    Coe, R.; Saito, S.

    1995-12-31

    MWD systems are currently used to monitor the direction of wellbores. MWD systems with higher temperature capabilities are required to meet the needs of deep and geothermal drilling. A technique has been developed for geothermal drilling that allows a fully retrievable MWD system to be used in wells with formation temperatures in excess of 350{degrees}C. This operational technique involves use of the MWD system in combination with operational procedures adapted to cope with the need for continuous directional control while drilling. Descriptions of the drilling environment are given in areas of Japan where high temperature drilling is performed. Possible future requirements are reviewed. The MWD system is described giving current technical specifications and capabilities. The operational method for utilizing the MWD is detailed. A summary of successful applications is discussed and specific case studies given. The efficiency of using the technique is reviewed.

  13. High Temperature Superconductivity and Cold Fusion

    NASA Astrophysics Data System (ADS)

    Rabinowitz, Mario

    There are numerous historical and scientific parallels between high temperature superconductivity (HTSC) and the newly emerging field of cold fusion (CF). Just as the charge carrier effective mass plays an important role in SC, the deuteron effective mass may play a vital role in CF. A new theory including effects of proximity, electron shielding, and decreased effective mass of the fusing nuclei can account for the reported CF results. A quantum-gas model that covers the range from low temperature to superhigh temperature SC indicates an increased Tc with reduced dimensionality. A reduced dimensionality effect may also enhance CF. A relation is shown between CF and the significant cluster-impact fusion experiments.

  14. High refractive index and temperature sensitivity LPGs for high temperature operation

    NASA Astrophysics Data System (ADS)

    Nascimento, I. M.; Gouveia, C.; Jana, Surnimal; Bera, Susanta; Baptista, J. M.; Moreira, Paulo; Biwas, Palas; Bandyopadhyay, Somnath; Jorge, Pedro A. S.

    2013-11-01

    A fiber optic sensor for high sensitivity refractive index and temperature measurement able to withstand temperature up to 450 °C is reported. Two identical LPG gratings were fabricated, whereas one was coated with a high refractive index (~1.78) sol-gel thin film in order to increase its sensitivity to the external refractive index. The two sensors were characterized and compared in refractive index and temperature. Sensitivities of 1063 nm/RIU (1.338 - 1.348) and 260 pm/°C were achieved for refractive index and temperature, respectively.

  15. High-temperature metal-organic magnets.

    PubMed

    Jain, Rajsapan; Kabir, Khayrul; Gilroy, Joe B; Mitchell, Keith A R; Wong, Kin-chung; Hicks, Robin G

    2007-01-18

    For over two decades there have been intense efforts aimed at the development of alternatives to conventional magnets, particularly materials comprised in part or wholly of molecular components. Such alternatives offer the prospect of realizing magnets fabricated through controlled, low-temperature, solution-based chemistry, as opposed to high-temperature metallurgical routes, and also the possibility of tuning magnetic properties through synthesis. However, examples of magnetically ordered molecular materials at or near room temperature are extremely rare, and the properties of these materials are often capricious and difficult to reproduce. Here we present a versatile solution-based route to a new class of metal-organic materials exhibiting magnetic order well above room temperature. Reactions of the metal (M) precursor complex bis(1,5-cyclooctadiene)nickel with three different organics A-TCNE (tetracyanoethylene), TCNQ (7,7,8,8-tetracyanoquinodimethane) or DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquinone)--proceed via electron transfer from nickel to A and lead to materials containing Ni(II) ions and reduced forms of A in a 2:1 Ni:A ratio--that is, opposite to that of conventional (low Curie temperature) MA(2)-type magnets. These materials also contain oxygen-based species within their architectures. Magnetic characterization of the three compounds reveals spontaneous field-dependent magnetization and hysteresis at room temperature, with ordering temperatures well above ambient. The unusual stoichiometry and striking magnetic properties highlight these three compounds as members of a class of stable magnets that are at the interface between conventional inorganic magnets and genuine molecule-based magnets.

  16. Plasma synthesis of high temperature ceramic films

    SciTech Connect

    Brown, I.G.; Monteiro, O.R.

    1998-11-01

    Thin films of alumina, chromia, mullite, yttria and zirconia have been synthesized using a plasma-based method called metal plasma immersion ion implantation and deposition (Mepiiid)--a highly versatile plasma deposition technique with ion energy control. Monolithic films (a single ceramic component) and multilayer films (individual layers of different ceramic materials) were formed. The films were characterized for their composition and structure in a number of different ways, and the high temperature performance of the films was explored, particularly for their ability to maintain their integrity and adhesion when subjected to repetitive high temperature thermal cycling up 1100 C. We found that the films retain their adhesion and quality without any apparent degradation with time, even after a large number of cycles; (the tests were extended out to a total of 40 cycles each of 24 hours duration). After repetitive high temperature thermal cycling, the film-substrate adhesion was greater than {approx}70 Mpa, the instrumental limit of measurement, and the interface toughness was approximately 0.8 MPa m{sup 1/2}.

  17. Electrochemical high-temperature gas sensors

    NASA Astrophysics Data System (ADS)

    Saruhan, B.; Stranzenbach, M.; Yüce, A.; Gönüllü, Y.

    2012-06-01

    Combustion produced common air pollutant, NOx associates with greenhouse effects. Its high temperature detection is essential for protection of nature. Component-integration capable high-temperature sensors enable the control of combustion products. The requirements are quantitative detection of total NOx and high selectivity at temperatures above 500°C. This study reports various approaches to detect NO and NO2 selectively under lean and humid conditions at temperatures from 300°C to 800°C. All tested electrochemical sensors were fabricated in planar design to enable componentintegration. We suggest first an impedance-metric gas sensor for total NOx-detection consisting of NiO- or NiCr2O4-SE and PYSZ-electrolyte. The electrolyte-layer is about 200μm thickness and constructed of quasi-single crystalline columns. The sensing-electrode (SE) is magnetron sputtered thin-layers of NiO or NiCr2O4. Sensor sensitivity for detection of total NOx has been measured by applying impedance analysis. The cross-sensitivity to other emission gases such as CO, CO2, CH4 and oxygen (5 vol.%) has been determined under 0-1000ppm NO. Sensor maintains its high sensitivity at temperatures up to 550°C and 600°C, depending on the sensing-electrode. NiO-SE yields better selectivity to NO in the presence of oxygen and have shorter response times comparing to NiCr2O4-SE. For higher temperature NO2-sensing capability, a resistive DC-sensor having Al-doped TiO2-sensing layers has been employed. Sensor-sensitivity towards NO2 and cross-sensitivity to CO has been determined in the presence of H2O at temperatures 600°C and 800°C. NO2 concentrations varying from 25 to 100ppm and CO concentrations from 25 to 75ppm can be detected. By nano-tubular structuring of TiO2, NO2 sensitivity of the sensor was increased.

  18. Sponge-Microbe Associations Survive High Nutrients and Temperatures

    PubMed Central

    Simister, Rachel; Taylor, Michael W.; Tsai, Peter; Webster, Nicole

    2012-01-01

    Coral reefs are under considerable pressure from global stressors such as elevated sea surface temperature and ocean acidification, as well as local factors including eutrophication and poor water quality. Marine sponges are diverse, abundant and ecologically important components of coral reefs in both coastal and offshore environments. Due to their exceptionally high filtration rates, sponges also form a crucial coupling point between benthic and pelagic habitats. Sponges harbor extensive microbial communities, with many microbial phylotypes found exclusively in sponges and thought to contribute to the health and survival of their hosts. Manipulative experiments were undertaken to ascertain the impact of elevated nutrients and seawater temperature on health and microbial community dynamics in the Great Barrier Reef sponge Rhopaloeides odorabile. R. odorabile exposed to elevated nutrient levels including 10 µmol/L total nitrogen at 31°C appeared visually similar to those maintained under ambient seawater conditions after 7 days. The symbiotic microbial community, analyzed by 16S rRNA gene pyrotag sequencing, was highly conserved for the duration of the experiment at both phylum and operational taxonomic unit (OTU) (97% sequence similarity) levels with 19 bacterial phyla and 1743 OTUs identified across all samples. Additionally, elevated nutrients and temperatures did not alter the archaeal associations in R. odorabile, with sequencing of 16S rRNA gene libraries revealing similar Thaumarchaeota diversity and denaturing gradient gel electrophoresis (DGGE) revealing consistent amoA gene patterns, across all experimental treatments. A conserved eukaryotic community was also identified across all nutrient and temperature treatments by DGGE. The highly stable microbial associations indicate that R. odorabile symbionts are capable of withstanding short-term exposure to elevated nutrient concentrations and sub-lethal temperatures. PMID:23284943

  19. High-Temperature Piezoelectric Ceramic Developed

    NASA Technical Reports Server (NTRS)

    Sayir, Ali; Farmer, Serene C.; Dynys, Frederick W.

    2005-01-01

    Active combustion control of spatial and temporal variations in the local fuel-to-air ratio is of considerable interest for suppressing combustion instabilities in lean gas turbine combustors and, thereby, achieving lower NOx levels. The actuator for fuel modulation in gas turbine combustors must meet several requirements: (1) bandwidth capability of 1000 Hz, (2) operating temperature compatible with the fuel temperature, which is in the vicinity of 400 F, (3) stroke of approximately 4 mils (100 m), and (4) force of 300 lb-force. Piezoelectric actuators offer the fastest response time (microsecond time constants) and can generate forces in excess of 2000 lb-force. The state-of-the-art piezoceramic material in industry today is Pb(Zr,Ti)O3, called PZT. This class of piezoelectric ceramic is currently used in diesel fuel injectors and in the development of high-response fuel modulation valves. PZT materials are generally limited to operating temperatures of 250 F, which is 150 F lower than the desired operating temperature for gas turbine combustor fuel-modulation injection valves. Thus, there is a clear need to increase the operating temperature range of piezoceramic devices for active combustion control in gas turbine engines.

  20. Nontrivial center dominance in high temperature QCD

    NASA Astrophysics Data System (ADS)

    Ishikawa, K.-I.; Iwasaki, Y.; Nakayama, Yu; Yoshie, T.

    2016-07-01

    We investigate the properties of quarks and gluons above the chiral phase transition temperature Tc, using the renormalization group (RG) improved gauge action and the Wilson quark action with two degenerate quarks mainly on a 323 × 16 lattice. In the one-loop perturbation theory, the thermal ensemble is dominated by the gauge configurations with effectively Z(3) center twisted boundary conditions, making the thermal expectation value of the spatial Polyakov loop take a nontrivial Z(3) center. This is in agreement with our lattice simulation of high temperature quantum chromodynamics (QCD). We further observe that the temporal propagator of massless quarks at extremely high temperature β = 100.0(T ≃ 1058T c) remarkably agrees with the temporal propagator of free quarks with the Z(3) twisted boundary condition for t/Lt ≥ 0.2, but differs from that with the Z(3) trivial boundary condition. As we increase the mass of quarks mq, we find that the thermal ensemble continues to be dominated by the Z(3) twisted gauge field configurations as long as mq ≤ 3.0T and above that the Z(3) trivial configurations come in. The transition is similar to what we found in the departure from the conformal region in the zero-temperature many-flavor conformal QCD on a finite lattice by increasing the mass of quarks.

  1. Evaluation of high temperature capacitor dielectrics

    NASA Technical Reports Server (NTRS)

    Hammoud, Ahmad N.; Myers, Ira T.

    1992-01-01

    Experiments were carried out to evaluate four candidate materials for high temperature capacitor dielectric applications. The materials investigated were polybenzimidazole polymer and three aramid papers: Voltex 450, Nomex 410, and Nomex M 418, an aramid paper containing 50 percent mica. The samples were heat treated for six hours at 60 C and the direct current and 60 Hz alternating current breakdown voltages of both dry and impregnated samples were obtained in a temperature range of 20 to 250 C. The samples were also characterized in terms of their dielectric constant, dielectric loss, and conductivity over this temperature range with an electrical stress of 60 Hz, 50 V/mil present. Additional measurements are underway to determine the volume resistivity, thermal shrinkage, and weight loss of the materials. Preliminary data indicate that the heat treatment of the films slightly improves the dielectric properties with no influence on their breakdown behavior. Impregnation of the samples leads to significant increases in both alternating and direct current breakdown strength. The results are discussed and conclusions made concerning their suitability as high temperature capacitor dielectrics.

  2. Medium Deep High Temperature Heat Storage

    NASA Astrophysics Data System (ADS)

    Bär, Kristian; Rühaak, Wolfram; Schulte, Daniel; Welsch, Bastian; Chauhan, Swarup; Homuth, Sebastian; Sass, Ingo

    2015-04-01

    Heating of buildings requires more than 25 % of the total end energy consumption in Germany. Shallow geothermal systems for indirect use as well as shallow geothermal heat storage systems like aquifer thermal energy storage (ATES) or borehole thermal energy storage (BTES) typically provide low exergy heat. The temperature levels and ranges typically require a coupling with heat pumps. By storing hot water from solar panels or thermal power stations with temperatures of up to 110 °C a medium deep high temperature heat storage (MDHTS) can be operated on relatively high temperature levels of more than 45 °C. Storage depths of 500 m to 1,500 m below surface avoid conflicts with groundwater use for drinking water or other purposes. Permeability is typically also decreasing with greater depth; especially in the crystalline basement therefore conduction becomes the dominant heat transport process. Solar-thermal charging of a MDHTS is a very beneficial option for supplying heat in urban and rural systems. Feasibility and design criteria of different system configurations (depth, distance and number of BHE) are discussed. One system is designed to store and supply heat (300 kW) for an office building. The required boreholes are located in granodioritic bedrock. Resulting from this setup several challenges have to be addressed. The drilling and completion has to be planned carefully under consideration of the geological and tectonical situation at the specific site.

  3. Noise temperature in graphene at high frequencies

    NASA Astrophysics Data System (ADS)

    Rengel, Raúl; Iglesias, José M.; Pascual, Elena; Martín, María J.

    2016-07-01

    A numerical method for obtaining the frequency-dependent noise temperature in monolayer graphene is presented. From the mobility and diffusion coefficient values provided by Monte Carlo simulation, the noise temperature in graphene is studied up to the THz range, considering also the influence of different substrate types. The influence of the applied electric field is investigated: the noise temperature is found to increase with the applied field, dropping down at high frequencies (in the sub-THz range). The results show that the low-frequency value of the noise temperature in graphene on a substrate tends to be reduced as compared to the case of suspended graphene due to the important effect of remote polar phonon interactions, thus indicating a reduced emitted noise power; however, at very high frequencies the influence of the substrate tends to be significantly reduced, and the differences between the suspended and on-substrate cases tend to be minimized. The values obtained are comparable to those observed in GaAs and semiconductor nitrides.

  4. Evaluation of high temperature capacitor dielectrics

    NASA Astrophysics Data System (ADS)

    Hammoud, Ahmad N.; Myers, Ira T.

    Experiments were carried out to evaluate four candidate materials for high temperature capacitor dielectric applications. The materials investigated were polybenzimidazole polymer and three aramid papers: Voltex 450, Nomex 410, and Nomex M 418, an aramid paper containing 50 percent mica. The samples were heat treated for six hours at 60 C and the direct current and 60 Hz alternating current breakdown voltages of both dry and impregnated samples were obtained in a temperature range of 20 to 250 C. The samples were also characterized in terms of their dielectric constant, dielectric loss, and conductivity over this temperature range with an electrical stress of 60 Hz, 50 V/mil present. Additional measurements are underway to determine the volume resistivity, thermal shrinkage, and weight loss of the materials. Preliminary data indicate that the heat treatment of the films slightly improves the dielectric properties with no influence on their breakdown behavior. Impregnation of the samples leads to significant increases in both alternating and direct current breakdown strength. The results are discussed and conclusions made concerning their suitability as high temperature capacitor dielectrics.

  5. High-precision abundances of Sc, Mn, Cu, and Ba in solar twins. Trends of element ratios with stellar age

    NASA Astrophysics Data System (ADS)

    Nissen, P. E.

    2016-09-01

    Aims: A previous study of correlations between element abundances and ages of solar twin stars in the solar neighborhood is extended to include Sc, Mn, Cu, and Ba to obtain new information on the nucleosynthetic history of these elements. Methods: HARPS spectra with S/N ≳ 600 are used to derive very precise (σ ~ 0.01 dex) differential abundances of Sc, Mn, Cu, and Ba for 21 solar twins and the Sun. The analysis is based on MARCS model atmospheres with parameters determined from the excitation and ionization balance of Fe lines. Stellar ages with internal errors less than 1 Gyr are obtained by interpolation in the log g - Teff diagram between isochrones based on the Aarhus Stellar Evolution Code. Results: For stars younger than 6 Gyr, [Sc/Fe], [Mn/Fe], [Cu/Fe], and [Ba/Fe] are tightly correlated with stellar age, which is also the case for the other elements previously studied; linear relations between [X/Fe] and age have χ^2red ˜ 1, and for most stars the residuals do not depend on elemental condensation temperature. For ages between 6 and 9 Gyr, the [X/Fe] - age correlations break down and the stars split up into two groups having respectively high and low [X/Fe] for the odd-Z elements Na, Al, Sc, and Cu. Conclusions: While stars in the solar neighborhood younger than ~ 6 Gyr were formed from interstellar gas with a smooth chemical evolution, older stars seem to have originated from regions enriched by supernovae with different neutron excesses. Correlations between abundance ratios and stellar age suggest that: (i) Sc is made in Type II supernovae along with the α-capture elements; (ii) the Type II to Ia yield ratio is about the same for Mn and Fe; (iii) Cu is mainly made by the weak s-process in massive stars; (iv) the Ba/Y yield ratio for asymptotic giant branch stars increases with decreasing stellar mass; (v) [Y/Mg] and [Y/Al] can be used as chemical clocks when determining ages of solar metallicity stars. Based on data products from observations made

  6. High temperature furnace modeling and performance verifications

    NASA Technical Reports Server (NTRS)

    Smith, James E., Jr.

    1988-01-01

    Analytical, numerical and experimental studies were performed on two classes of high temperature materials processing furnaces. The research concentrates on a commercially available high temperature furnace using zirconia as the heating element and an arc furnace based on a ST International tube welder. The zirconia furnace was delivered and work is progressing on schedule. The work on the arc furnace was initially stalled due to the unavailability of the NASA prototype, which is actively being tested aboard the KC-135 experimental aircraft. A proposal was written and funded to purchase an additional arc welder to alleviate this problem. The ST International weld head and power supply were received and testing will begin in early November. The first 6 months of the grant are covered.

  7. Precision control of high temperature furnaces

    SciTech Connect

    Pollock, G.G.

    1994-12-31

    It is an object of the present invention to provide precision control of high temperature furnaces. It is another object of the present invention to combine the power of two power supplies of greatly differing output capacities in a single furnace. This invention combines two power supplies to control a furnace. A main power supply heats the furnace in the traditional manner, while the power from the auxiliary supply is introduced as a current flow through charged particles existing due to ionized gas or thermionic emission. The main power supply provides the bulk heating power and the auxiliary supply provides a precise and fast power source such that the precision of the total power delivered to the furnace is improved. Further, this invention comprises a means for high speed measurement of temperature of the process by the method of measuring the amount of current flow in a deliberately induced charged particle current.

  8. High temperature superconductors for magnetic suspension applications

    NASA Technical Reports Server (NTRS)

    Mcmichael, C. K.; Cooley, R. S.; Chen, Q. Y.; Ma, K. B.; Lamb, M. A.; Meng, R. L.; Chu, C. W.; Chu, W. K.

    1994-01-01

    High temperature superconductors (HTS) hold the promise for applications in magnetic levitation bearings, vibration damping, and torque coupling. Traditional magnetic suspension systems require active feedback and vibration controls in which power consumption and low frequency vibration are among the major engineering concerns. HTS materials have been demonstrated to be an enabling approach towards such problems due to their flux trapping properties. In our laboratory at TCSUH, we have been conducting a series of experiments to explore various mechanical applications using HTS. We have constructed a 30 lb. model flywheel levitated by a hybrid superconducting magnetic bearing (HSMB). We are also developing a levitated and vibration-dampled platform for high precision instrumentation. These applications would be ideal for space usages where ambient temperature is adequate for HTS to operate properly under greatly reduced cryogenic requirements. We will give a general overview of these potential applications and discuss the operating principles of the HTS devices we have developed.

  9. High temperature superconductor materials and applications

    NASA Technical Reports Server (NTRS)

    Doane, George B., III. (Editor); Banks, Curtis; Golben, John

    1991-01-01

    One of the areas concerned itself with the investigation of the phenomena involved in formulating and making in the laboratory new and better superconductor material with enhanced values of critical current and temperature. Of special interest were the chemistry, physical processes, and environment required to attain these enhanced desirable characteristics. The other area concerned itself with producing high temperature superconducting thin films by pulsed laser deposition techniques. Such films are potentially very useful in the detection of very low power signals. To perform this research high vacuum is required. In the course of this effort, older vacuum chambers were maintained and used. In addition, a new facility is being brought on line. This latter activity has been replete with the usual problems of bringing a new facility into service. Some of the problems are covered in the main body of this report.

  10. Hole-doped cuprate high temperature superconductors

    NASA Astrophysics Data System (ADS)

    Chu, C. W.; Deng, L. Z.; Lv, B.

    2015-07-01

    Hole-doped cuprate high temperature superconductors have ushered in the modern era of high temperature superconductivity (HTS) and have continued to be at center stage in the field. Extensive studies have been made, many compounds discovered, voluminous data compiled, numerous models proposed, many review articles written, and various prototype devices made and tested with better performance than their nonsuperconducting counterparts. The field is indeed vast. We have therefore decided to focus on the major cuprate materials systems that have laid the foundation of HTS science and technology and present several simple scaling laws that show the systematic and universal simplicity amid the complexity of these material systems, while referring readers interested in the HTS physics and devices to the review articles. Developments in the field are mostly presented in chronological order, sometimes with anecdotes, in an attempt to share some of the moments of excitement and despair in the history of HTS with readers, especially the younger ones.

  11. Magnetic suspension using high temperature superconducting cores

    NASA Technical Reports Server (NTRS)

    Scurlock, R. G.

    1992-01-01

    The development of YBCO high temperature superconductors, in wire and tape forms, is rapidly approaching the point where the bulk transport current density j vs magnetic field H characteristics with liquid nitrogen cooling will enable its use in model cores. On the other hand, BSCCO high temperature superconductor in wire form has poor j-H characteristics at 77 K today, although with liquid helium or hydrogen cooling, it appears to be superior to NbTi superconductor. Since liquid nitrogen cooling is approx. 100 times cheaper than liquid helium cooling, the use of YBCO is very attractive for use in magnetic suspension. The design is discussed of a model core to accommodate lift and drag loads up to 6000 and 3000 N respectively. A comparison is made between the design performance of a liquid helium cooled NbTi (or BSCCO) superconducting core and a liquid nitrogen cooled YBCO superconducting core.

  12. Copepods attain high abundance, biomass and production in the absence of large predators but suffer cannibalistic loss

    NASA Astrophysics Data System (ADS)

    Uye, Shin-ichi; Liang, Dong

    1998-06-01

    Zooplankton samples were collected at intervals of 3-5 days for a year in Fukuyama Harbor, a eutrophic inlet of the Inland Sea of Japan, using a 62-μm-mesh plankton net. The copepod community, which consisted of twelve species, had a very high abundance, biomass and production rate. Acartia omorii, Centropages abdominalis, Oithona davisae and Paracalanus sp. were the most abundant species. The annual average abundance and biomass of adults and copepodites were 1.10×10 5 ind. m -3 and 39.1 mg C m -3, respectively, one of the highest values so far reported in coastal marine waters. The annual average production rate was 6.85 mg C m -3 d -1, of which Paracalanus sp., O. davisae, A. omorii and C. abdominalis accounted for 27, 26, 25 and 13%, respectively. The combination of an abundant food supply and scarce large predators, except for the ctenophore Bolinopsis mikado which was abundant only in mid-summer, allowed the high abundance, biomass and production of copepods. However, predation on copepod eggs and early nauplii by adults and late copepodites reduced the population recruitment rate and copepod production.

  13. Trends in Surface Temperature at High Latitudes

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.

    2012-01-01

    The earliest signal of a climate change is expected to be found in the polar regions where warming is expected to be amplified on account of ice-albedo feedbacks associated with the high reflectivity of snow and ice. Because of general inaccessibility, there is a general paucity of in situ data and hence the need to use satellite data to observe the large-scale variability and trends in surface temperature in the region. Among the most important sensors for monitoring surface temperature has been the Advanced Very High Resolution Radiometer (AVHRR) which was first launched in 1978 and has provided continuous thermal infrared data since 1981. The top of the atmosphere data are converted to surface temperature data through various schemes that accounts for the unique atmospheric and surface conditions in the polar regions. Among the highest source of error in the data is cloud masking which is made more difficult in the polar region because of similar Signatures of clouds and snow lice covered areas. The availability of many more channels in the Moderate Resolution Imaging Spectroradiometer (MODIS) launched on board Terra satellite in December 1999 and on board Aqua in May 2002 (e.g., 36 visible and infrared channels compared to 5 for AVHRR) made it possible to minimize the error. Further capabilities were introduced with the Advanced Microwave Scanning Radiometer (AMSR) which has the appropriate frequency channels for the retrieval of sea surface temperature (SST). The results of analysis of the data show an amplified warming in the Arctic region, compared with global warming. The spatial distribution of warming is, however, not uniform and during the last 3 decades, positive temperature anomalies have been most pronounced in North America, Greenland and the Arctic basin. Some regions of the Arctic such as Siberia and the Bering Sea surprisingly show moderate cooling but this may be because these regions were anomalously warm in the 1980s when the satellite record

  14. A high temperature superconductivity communications flight experiment

    NASA Technical Reports Server (NTRS)

    Ngo, P.; Krishen, K.; Arndt, D.; Raffoul, G.; Karasack, V.; Bhasin, K.; Leonard, R.

    1992-01-01

    The proposed high temperature superconductivity (HTSC) millimeter-wave communications flight experiment from the payload bay of the Space Shuttle Orbiter to the Advanced Communications Technology Satellite (ACTS) in geosynchronous orbit is described. The experiment will use a Ka-band HTSC phased array antenna and front-end electronics to receive a downlink communications signal from the ACTS. The discussion covers the system configuration, a description of the ground equipment, the spacecraft receiver, link performance, thermal loading, and the superconducting antenna array.

  15. Atomic absorption spectroscopy with high temperature flames.

    PubMed

    Willis, J B

    1968-07-01

    An account is given of the history of the development of high temperature flames for the atomic absorption measurement of metals forming refractory oxides. The principles governing the design of premix burners for such flames, and the relative merits of different types of nebulizer burner systems are described. After a brief account of the structure and emission characteristics of the premixed oxygen-acetylene and nitrous oxide-acetylene flames, the scope and limitations of the latter flame in chemical analysis are discussed.

  16. Intermetallic-Based High-Temperature Materials

    SciTech Connect

    Sikka, V.K.

    1999-04-25

    The intermetallic-based alloys for high-temperature applications are introduced. General characteristics of intermetallics are followed by identification of nickel and iron aluminides as the most practical alloys for commercial applications. An overview of the alloy compositions, melting processes, and mechanical properties for nickel and iron aluminizes are presented. The current applications and commercial producers of nickel and iron aluminizes are given. A brief description of the future prospects of intermetallic-based alloys is also given.

  17. Establishment of Harrop, High-Temperature Viscometer

    SciTech Connect

    Schumacher, R.F.

    1999-11-05

    This report explains how the Harrop, High-Temperature Viscometer was installed, calibrated, and operated. This report includes assembly and alignment of the furnace, viscometer, and spindle, and explains the operation of the Brookfield Viscometer, the Harrop furnace, and the UDC furnace controller. Calibration data and the development of the spindle constant from NIST standard reference glasses is presented. A simple operational procedure is included.

  18. High temperature, flexible, fiber-preform seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor); Strocky, Paul J. (Inventor)

    1992-01-01

    A seal is mounted in a rectangular groove in a movable structural panel. The seal comprises a fiber preform constructed of multiple layers of fiber having a uniaxial core. Helical fibers are wound over the core. The fibers are of materials capable of withstanding high temperatures and are both left-hand and right-hand wound. An outer layer wrapped over said helical fibers prevents abrasion damage.

  19. Thermal fuse for high-temperature batteries

    DOEpatents

    Jungst, Rudolph G.; Armijo, James R.; Frear, Darrel R.

    2000-01-01

    A thermal fuse, preferably for a high-temperature battery, comprising leads and a body therebetween having a melting point between approximately 400.degree. C. and 500.degree. C. The body is preferably an alloy of Ag--Mg, Ag--Sb, Al--Ge, Au--In, Bi--Te, Cd--Sb, Cu--Mg, In--Sb, Mg--Pb, Pb--Pd, Sb--Zn, Sn--Te, or Mg--Al.

  20. Passivation Of High-Temperature Superconductors

    NASA Technical Reports Server (NTRS)

    Vasquez, Richard P.

    1991-01-01

    Surfaces of high-temperature superconductors passivated with native iodides, sulfides, or sulfates formed by chemical treatments after superconductors grown. Passivating compounds nearly insoluble in and unreactive with water and protect underlying superconductors from effects of moisture. Layers of cuprous iodide and of barium sulfate grown. Other candidate passivating surface films: iodides and sulfides of bismuth, strontium, and thallium. Other proposed techniques for formation of passivating layers include deposition and gas-phase reaction.

  1. High Temperature Decomposition of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydropemxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  2. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2005-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  3. Caldron For High-Temperature Alloys

    NASA Technical Reports Server (NTRS)

    Geringer, Henry J.

    1989-01-01

    Induction-heated caldron melts high-temperature alloys. Prevents sort of contamination of melts occurring during arc melting in ceramic crucibles. Liquefies 200 grams of solid metal components of alloy like niobium aluminum and makes alloy homogeneous in less than 3 minutes. Plugged sleeve constitutes main body of caldron. Coolant flows through sleeve to prevent it from melting. Mandrel-wound induction coils adjusted to tune source of power. Also serves as mold for casting alloys into such shapes as bars.

  4. High Temperature Strain Gage Calibration Fixture

    NASA Technical Reports Server (NTRS)

    Vranas, T. (Inventor)

    1976-01-01

    An apparatus and method are described for calibrating high temperature strain gases which serve for both dead weight and constant deflection measurements. A cantilever support arm allows the test unit to slide into a furnace while one end is subjected to bending strain either by hanging weights upon it or by deflecting it with a push rod. The dual nature of the fixture permits both tests to be run without change of the test specimen or removal from the furnace.

  5. Nickel alloys combat high-temperature corrosion

    SciTech Connect

    Agarwal, D.C.; Herda, W.R.; Brill, U.

    1995-10-01

    During the last few decades, a better understanding of alloying effects, advances in melting technology, and the development of controlled thermomechanical processing have led to new and improved high-temperature alloys. Most such alloys have sufficient amounts of chromium (with or without additions of aluminum or silicon) to form chromium oxide, alumina, and/or silica protective oxide scales, which provide resistance to environmental degradation. However, oxides cannot protect against failure by creep, mechanical or thermal fatigue, thermal shock, or embrittlement. In the real world, failure is typically caused by a combination of two or more attack modes, which synergistically accelerate degradation. To counter these attacks, two new nickel-base alloys have been developed, in which high-temperature corrosion resistance has been optimized by the careful addition of elements such as chromium, aluminum, silicon, and rare earths. They provide economical and reliable solutions to attack by oxygen, sulfur, halogens, carbon compounds, and nitrogen in a range of high-temperature applications. For example, Alloy 602CA is utilized in heat treating equipment, catalytic automotive parts, and chemical processing apparatus. Alloy 45TM has been successfully used in coal gasification equipment, incinerators, refineries, and process machinery involving severe sulfidizing conditions.

  6. Phylogenetic analysis of microalgae based on highly abundant proteins using mass spectrometry.

    PubMed

    Lee, Hae-Won; Roh, Seong Woon; Cho, Kichul; Kim, Kil-Nam; Cha, In-Tae; Yim, Kyung June; Song, Hye Seon; Nam, Young-Do; Oda, Tatsuya; Chung, Young-Ho; Kim, Soo Jung; Choi, Jong-Soon; Kim, Daekyung

    2015-01-01

    The blooms of toxic phototrophic microorganisms, such as microalgae and cyanobacteria, which are typically found in freshwater and marine environments, are becoming more frequent and problematic in aquatic systems. Due to accumulation of toxic algae, harmful algal blooms (HABs) exert negative effects on aquatic systems. Therefore, rapid detection of harmful microalgae is important for monitoring the occurrence of HABs. Mass spectrometry-based methods have become sensitive, specific techniques for the identification and characterization of microorganisms. Matrix-assisted laser desorption/ionization (MALDI) with time-of-flight (TOF) mass spectrometry (MS) allows us to measure a unique molecular fingerprint of highly abundant proteins in a microorganism and has been used for the rapid, accurate identification of bacteria and fungi in clinical microbiology. Here, we tested the specificity of MALDI-TOF MS using microalgal strains (Heterocapsa, Alexandrium, Nannochloropsis, Chaetoceros, Chlorella, and Dunaliella spp.). Our research suggested that this method was comparable in terms of the rapid identification of microalgea to conventional methods based on genetic information and morphology. Thus, this efficient mass spectrometry-based technique may have applications in the rapid identification of harmful microorganisms from aquatic environmental samples.

  7. High abundance and diversity of archaea from deep-sea sediments of the South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, P.; Li, T.; Hu, A.; Zhang, C.

    2009-12-01

    Archaea communities from two subseafloor sediment core MD05-2896 and MD05-2902 from the south china sea were evaluated by molecular analysis. Archaea abundances determined by FISH and DAPI were over 109 cells/gram along two cores and the portion of archaea to microbial community ranged from 29% to 57% in our study, indicating the important role of archaea in South China Sea. The most of Shannon index of two sites were over 1.5, indicating the high diversity of archaea in South China Sea. The phylogenetic analysis showed that the spatial community structure of two cores were different and the geographical position, TON were the main factors for the difference. A. Depth profiles of total prokaryotic cells in sediment cores. Open square (DAPI for MD05-2896), closed square (FISH: EUB338+ARC915 for MD05-2896); open triangle (DAPI for MD05-2902), closed triangle (FISH: EUB338+ARC915 for MD05-2902) B. Archaeal percentage of total prokaryotic cells (FISH: EUB338+ARC915) in sediment cores. Open circle (MD05-2896), closed circle (MD05-2902)

  8. Phylogenetic analysis of microalgae based on highly abundant proteins using mass spectrometry.

    PubMed

    Lee, Hae-Won; Roh, Seong Woon; Cho, Kichul; Kim, Kil-Nam; Cha, In-Tae; Yim, Kyung June; Song, Hye Seon; Nam, Young-Do; Oda, Tatsuya; Chung, Young-Ho; Kim, Soo Jung; Choi, Jong-Soon; Kim, Daekyung

    2015-01-01

    The blooms of toxic phototrophic microorganisms, such as microalgae and cyanobacteria, which are typically found in freshwater and marine environments, are becoming more frequent and problematic in aquatic systems. Due to accumulation of toxic algae, harmful algal blooms (HABs) exert negative effects on aquatic systems. Therefore, rapid detection of harmful microalgae is important for monitoring the occurrence of HABs. Mass spectrometry-based methods have become sensitive, specific techniques for the identification and characterization of microorganisms. Matrix-assisted laser desorption/ionization (MALDI) with time-of-flight (TOF) mass spectrometry (MS) allows us to measure a unique molecular fingerprint of highly abundant proteins in a microorganism and has been used for the rapid, accurate identification of bacteria and fungi in clinical microbiology. Here, we tested the specificity of MALDI-TOF MS using microalgal strains (Heterocapsa, Alexandrium, Nannochloropsis, Chaetoceros, Chlorella, and Dunaliella spp.). Our research suggested that this method was comparable in terms of the rapid identification of microalgea to conventional methods based on genetic information and morphology. Thus, this efficient mass spectrometry-based technique may have applications in the rapid identification of harmful microorganisms from aquatic environmental samples. PMID:25476355

  9. High fungal diversity and abundance recovered in the deep-sea sediments of the Pacific Ocean.

    PubMed

    Xu, Wei; Pang, Ka-Lai; Luo, Zhu-Hua

    2014-11-01

    Knowledge about the presence and ecological significance of bacteria and archaea in the deep-sea environments has been well recognized, but the eukaryotic microorganisms, such as fungi, have rarely been reported. The present study investigated the composition and abundance of fungal community in the deep-sea sediments of the Pacific Ocean. In this study, a total of 1,947 internal transcribed spacer (ITS) regions of fungal rRNA gene clones were recovered from five sediment samples at the Pacific Ocean (water depths ranging from 5,017 to 6,986 m) using three different PCR primer sets. There were 16, 17, and 15 different operational taxonomic units (OTUs) identified from fungal-universal, Ascomycota-, and Basidiomycota-specific clone libraries, respectively. Majority of the recovered sequences belonged to diverse phylotypes of Ascomycota (25 phylotypes) and Basidiomycota (18 phylotypes). The multiple primer approach totally recovered 27 phylotypes which showed low similarities (≤97 %) with available fungal sequences in the GenBank, suggesting possible new fungal taxa occurring in the deep-sea environments or belonging to taxa not represented in the GenBank. Our results also recovered high fungal LSU rRNA gene copy numbers (3.52 × 10(6) to 5.23 × 10(7)copies/g wet sediment) from the Pacific Ocean sediment samples, suggesting that the fungi might be involved in important ecological functions in the deep-sea environments.

  10. High Temperature VARTM of Phenylethynyl Terminated Imides

    NASA Technical Reports Server (NTRS)

    Ghose, Sayata; Cano, Roberto J.; Watson, Kent A.; Britton, Sean M.; Jensen, Brian J.; Connell, John W.; Herring, Helen M.; Linberry, Quentin J.

    2009-01-01

    Depending on the part type and quantity, fabrication of composite structures using vacuum assisted resin transfer molding (VARTM) can be more affordable than conventional autoclave techniques. Recent efforts have focused on adapting VARTM for the fabrication of high temperature composites. Due to their low melt viscosity and long melt stability, certain phenylethynyl terminated imides (PETI) can be processed into composites using high temperature VARTM (HT-VARTM). However, one of the disadvantages of the current HT-VARTM resin systems has been the high porosity of the resultant composites. For aerospace applications, the desired void fraction of less than 2% has not yet been achieved. In the current study, two PETI resins, LaRC PETI-330 and LaRC PETI-8 have been used to make test specimens using HT-VARTM. The resins were infused into ten layers of IM7-6K carbon fiber 5-harness satin fabric at 260 C or 280 C and cured at temperature up to 371 C. Initial runs yielded composites with high void content, typically greater than 7% by weight. A thermogravimetric-mass spectroscopic study was conducted to determine the source of volatiles leading to high porosity. It was determined that under the thermal cycle used for laminate fabrication, the phenylethynyl endcap was undergoing degradation leading to volatile evolution. This finding was unexpected as high quality composite laminates have been fabricated under higher pressures using these resin systems. The amount of weight loss experienced during the thermal cycle was only about 1% by weight, but this leads to a significant amount of volatiles in a closed system. By modifying the thermal cycle used in laminate fabrication, the void content was significantly reduced (typically 3% or less). The results of this work are presented herein.

  11. High temperature inorganic membranes for separating hydrogen

    SciTech Connect

    Fain, D.E.; Roettger, G.E.

    1995-08-01

    Effort has continued to accumulate data on the transport of gases over the temperature range from room temperature to 275{degrees}C with inorganic membranes having a range of pore radii from approximately 0.25 nm to 3 mn. An experimental alumina membrane having an estimated mean pore radius of 0.25 nm has been fabricated and tested. Extensive testing of this membrane indicated that the separation factor for helium and carbon tetrafluoride at 250{degrees}C was 59 and the extrapolated high temperature separation factor was 1,193. For safety reasons, earlier flow measurements concentrated on helium, carbon dioxide, and carbon tetrafluoride. New data have been acquired with hydrogen to verify the agreement with the other gases. During the measurements with hydrogen, it was noted that a considerable amount of moisture was present in the test gas. The source of this moisture and its effect on permeance was examined. Improvements were implemented to the flow test system to minimize the water content of the hydrogen test gas, and subsequent flow measurements have shown excellent results with hydrogen. The extrapolation of separation factors as a function of temperature continues to show promise as a means of using the hard sphere model to determine the pore size of membranes. The temperature dependence of helium transport through membranes appears to be considerably greater than other gases for the smallest pore sizes. The effort to extend temperature dependence to the hard sphere model continues to be delayed, primarily because of a lack of adequate adsorption data.

  12. Precipitation Hardenable High Temperature Shape Memory Alloy

    NASA Technical Reports Server (NTRS)

    Noebe, Ronald Dean (Inventor); Draper, Susan L. (Inventor); Nathal, Michael V. (Inventor); Crombie, Edwin A. (Inventor)

    2010-01-01

    A composition of the invention is a high temperature shape memory alloy having high work output, and is made from (Ni+Pt+Y),Ti(100-x) wherein x is present in a total amount of 49-55 atomic % Pt is present in a total amount of 10-30 atomic %, Y is one or more of Au, Pd. and Cu and is present in a total amount of 0 to 10 atomic %. The alloy has a matrix phase wherein the total concentration of Ni, Pt, and the one or more of Pd. Au, and Cu is greater than 50 atomic %.

  13. Structural relationships in high temperature superconductors

    SciTech Connect

    Schuller, I.K.; Segre, C.U.; Hinks, D.G.; Jorgensen, J.D.; Soderholm, L.; Beno, M.; Zhang, K.

    1987-09-01

    The recent discovery of two types of metallic copper oxide compounds which are superconducting to above 90/sup 0/K has renewed interest in the search for new high temperature superconducting materials. It is significant that both classes of compounds, La/sub 2-x/Sr/sub x/CuO/sub 4-y/ and YBa/sub 2/Cu/sub 3/O/sub 7-delta/ are intimately related to the extensively studied perovskite family. Both compounds contain highly oxidized, covalently bonded Cu-O sublattices, however, they differ in geometry. In this paper we discuss the relationship of these features to the superconducting properties. 30 refs., 6 figs.

  14. High temperature aqueous stress corrosion testing device

    DOEpatents

    Bornstein, A.N.; Indig, M.E.

    1975-12-01

    A description is given of a device for stressing tensile samples contained within a high temperature, high pressure aqueous environment, thereby permitting determination of stress corrosion susceptibility of materials in a simple way. The stressing device couples an external piston to an internal tensile sample via a pull rod, with stresses being applied to the sample by pressurizing the piston. The device contains a fitting/seal arrangement including Teflon and weld seals which allow sealing of the internal system pressure and the external piston pressure. The fitting/seal arrangement allows free movement of the pull rod and the piston.

  15. High Temperature Wear of Advanced Ceramics

    NASA Technical Reports Server (NTRS)

    DellaCorte, C.

    2005-01-01

    It was initially hypothesized that advanced ceramics would exhibit favorable high te- friction and wear properties because of their high hot hardness and low achievable surface roughness welding observed in metals does not occur in ceramics. More recent tribological studies of many nitride, carbide, oxide and composite ceramics, however, have revealed that ceramics often exhibit high friction and wear in non-lubricated, high temperature sliding contacts. A summary is given to measure friction and wear factor coefficients for a variety of ceramics from self mated ceramic pin-on-disk tests at temperatures from 25 to up to 1200 C. Observed steady state friction coefficients range from about 0.5 to 1.0 or above. Wear factor coefficients are also very high and range from about to 10(exp -5) to 10(exp -2) cubic millimeters per N-m. By comparison, oil lubricated steel sliding results in friction coefficients of 0.1 or less and wear factors less than 10(exp -9) cubic millimeters per N-m.

  16. High-temperature alloys for high-power thermionic systems

    SciTech Connect

    Shin, Kwang S.; Jacobson, D.L.; D'cruz, L.; Luo, Anhua; Chen, Bor-Ling.

    1990-08-01

    The need for structural materials with useful strength above 1600 k has stimulated interest in refractory-metal alloys. Tungsten possesses an extreme high modulus of elasticity as well as the highest melting temperature among metals, and hence is being considered as one of the most promising candidate materials for high temperature structural applications such as space nuclear power systems. This report is divided into three chapters covering the following: (1) the processing of tungsten base alloys; (2) the tensile properties of tungsten base alloys; and (3) creep behavior of tungsten base alloys. Separate abstracts were prepared for each chapter. (SC)

  17. LHDAC setup for high temperature and high pressure studies

    SciTech Connect

    Patel, Nishant N. Meenakshi, S. Sharma, Surinder M.

    2014-04-24

    A ytterbium fibre laser (λ = 1.07 μm) based laser heated diamond anvil cell (LHDAC) facility has been recently set up at HP and SRPD, BARC for simultaneous high temperature and high pressure investigation of material properties. Synthesis of GaN was carried out at pressure of ∼9 GPa and temperature of ∼1925 K in a Mao-Bell type diamond anvil cell (DAC) using the LHDAC facility. The retrieved sample has been characterized using our laboratory based micro Raman setup.

  18. High Temperature VARTM of Phenylethynyl Terminated Imides

    NASA Technical Reports Server (NTRS)

    Cano, Roberto J.; Britton, Sean M.; Jensen, Brian J.; Connell, John W.; Herring, Helen M.; Linberry, Quentin J.; Ghose, Sayata; Watson, Kent A.

    2009-01-01

    Fabrication of composite structures using vacuum assisted resin transfer molding (VARTM) is generally more affordable than conventional autoclave techniques. Recent efforts have focused on adapting VARTM for the fabrication of high temperature composites. Due to their low melt viscosity and long melt stability, certain phenylethynyl terminated imides (PETI) can be processed into composites using high temperature VARTM (HT-VARTM). However, one of the disadvantages of the current HT-VARTM resin systems has been the high porosity of the resultant composites. For aerospace applications, the desired void fraction of less than 2% has not yet been achieved. In the current study, two PETI resins, LaRC PETI-330 and LaRC PETI-8 have been used to make test specimens using HT-VARTM. The resins were infused into ten layers of IM7-6K carbon fiber 5-harness satin fabric at 260 C or 280 C and cured at 371 C. Initial runs yielded composites with high void content, typically greater than 7% by weight. A thermogravimetric-mass spectroscopic study was conducted to determine the source of volatiles leading to high porosity. It was determined that under the thermal cycle used for laminate fabrication, the phenylethynyl endcap was undergoing degradation leading to volatile evolution. By modifying the thermal cycle used in laminate fabrication, the void content was reduced significantly (typically approximately 3%). Densities of the composites were determined using a density gradient column and the glass transition temperatures of the cured composites were measured by dynamic mechanical analysis. Photomicrographs of the panels were taken and void contents were determined by acid digestion. The results of this work are presented herein.

  19. Improved Seals for High Temperature Airframe Applications

    NASA Technical Reports Server (NTRS)

    DeMange, Jeffrey J.; Dunlap, Patrick H.; Steinetz, Bruce M.

    2006-01-01

    Current thermal barrier seals, such as those used on the Space Shuttle, are insufficient to fully meet the demands of future hypersonic vehicles and reentry spacecraft. Previous investigations have demonstrated limited usage temperatures, as evidenced by a decreased ability to maintain sealing effectiveness at high temperatures (i.e., inadequate resiliency). In order to improve resiliency at elevated temperatures, Rene 41 (Allvac) was substituted for Inconel X-750 (Special Metals Corp.) as the spring tube material in the existing seal design. A seal construction incorporating the Rene 41 spring tube was fabricated and tested against the baseline Inconel X-750 spring tube seal. Although resiliency improvements were not as dramatic as in previous tests with the spring tubes alone, seals incorporating the Rene 41 spring tube exhibited an average 20 percent resiliency enhancement up to 1750 F when compared to seals containing the Inconel spring tube. In addition, the seals with the Rene 41 spring tubes showed less reduction in resiliency as temperatures increased above 1200 F. Results also indicated the Saffil (Saffil Ltd.) insulation in the core of the seal contributed more to resiliency than previously thought. Leakage data did not demonstrate an improvement with the seal containing the Rene 41 spring tube. However, based upon resiliency results, one could reasonably expect the Rene 41 version of the seal to track gap openings over a wider range. Therefore it would exhibit lower leakage than the Inconel X-750 version as the seal gap opens during a typical mission.

  20. High temperature measurement of water vapor absorption

    NASA Technical Reports Server (NTRS)

    Keefer, Dennis; Lewis, J. W. L.; Eskridge, Richard

    1985-01-01

    An investigation was undertaken to measure the absorption coefficient, at a wavelength of 10.6 microns, for mixtures of water vapor and a diluent gas at high temperature and pressure. The experimental concept was to create the desired conditions of temperature and pressure in a laser absorption wave, similar to that which would be created in a laser propulsion system. A simplified numerical model was developed to predict the characteristics of the absorption wave and to estimate the laser intensity threshold for initiation. A non-intrusive method for temperature measurement utilizing optical laser-beam deflection (OLD) and optical spark breakdown produced by an excimer laser, was thoroughly investigated and found suitable for the non-equilibrium conditions expected in the wave. Experiments were performed to verify the temperature measurement technique, to screen possible materials for surface initiation of the laser absorption wave and to attempt to initiate an absorption wave using the 1.5 kW carbon dioxide laser. The OLD technique was proven for air and for argon, but spark breakdown could not be produced in helium. It was not possible to initiate a laser absorption wave in mixtures of water and helium or water and argon using the 1.5 kW laser, a result which was consistent with the model prediction.

  1. High Temperature Materials for Chemical Propulsion Applications

    NASA Technical Reports Server (NTRS)

    Elam, Sandra; Hickman, Robert; O'Dell, Scott

    2007-01-01

    Radiation or passively cooled thrust chambers are used for a variety of chemical propulsion functions including apogee insertion, reaction control for launch vehicles, and primary propulsion for planetary spacecraft. The performance of these thrust chambers is limited by the operating temperature of available materials. Improved oxidation resistance and increased operating temperatures can be achieved with the use of thermal barrier coatings such as zirconium oxide (ZrO2) and hafnium oxide (HfO2). However, previous attempts to include these materials showed cracking and spalling of the oxide layer due to poor bonding. Current research at NASA's Marshall Space Flight Center (MSFC) has generated unique, high temperature material options for in-space thruster designs that are capable of up to 2500 C operating temperatures. The research is focused on fabrication technologies to form low cost Iridium,qF_.henium (Ir/Re) components with a ceramic hot wall created as an integral, functionally graded material (FGM). The goal of this effort is to further de?celop proven technologies for embedding a protective ceramic coating within the Ir/Re liner to form a robust functional gradient material. Current work includes the fabrication and testing of subscale samples to evaluate tensile, creep, thermal cyclic/oxidation, and thermophysical material properties. Larger test articles have also being fabricated and hot-fire tested to demonstrate the materials in prototype thrusters at 1O0 lbf thrust levels.

  2. High abundance androgen receptor in goldfish brain: characteristics and seasonal changes

    SciTech Connect

    Pasmanik, M.; Callard, G.V.

    1988-08-01

    Testosterone (T) exerts its actions in brain directly via androgen receptors or, after aromatization to estradiol, via estrogen receptors. Brain aromatase activity in teleost fish is 100-1000 times greater than in mammals and would be expected to significantly reduce the quantity of androgen available for receptor binding. Experiments were carried out on the goldfish Carassius auratus to determine if androgen receptors are present in teleost brain and whether their physicochemical properties reflect elevated aromatase. Cytosolic and nuclear extracts were assayed with the use of (/sup 3/H)T and charcoal, Sephadex LH-20, or DNA-cellulose chromatography to separate bound and free steroids. Binding activity was saturable and had an equally high affinity for T and 5 alpha-dihydrotestosterone. Although mibolerone was a relatively weak competitor, the putative teleost androgen 11-ketotestosterone, methyltrienolone (R1881), estradiol, progesterone, and cortisol were poor ligands. Characteristics that distinguish this receptor from a steroid-binding protein in goldfish serum are the presence of binding activity in both nuclear and cytosolic extracts, a low rate of ligand-receptor dissociation, electrophoretic mobility, sedimentation properties in low vs. high salt, and tissue distribution. DNA cellulose-adhering and nonadhering forms were detected, but these did not differ in other variables measured. Although goldfish androgen receptors resembled those of mammals in all important physicochemical characteristics, they were unusually abundant compared to levels in rat brain, but comparable to levels in prostate and other male sex hormone target organs. Moreover, there were seasonal variations in total receptors, with a peak at spawning (April) 4- to 5-fold higher than values in reproductively inactive fish.

  3. Scalable Synthesis of Defect Abundant Si Nanorods for High-Performance Li-Ion Battery Anodes.

    PubMed

    Wang, Jing; Meng, Xiangcai; Fan, Xiulin; Zhang, Wenbo; Zhang, Hongyong; Wang, Chunsheng

    2015-06-23

    Microsized nanostructured silicon-carbon composite is a promising anode material for high energy Li-ion batteries. However, large-scale synthesis of high-performance nano-Si materials at a low cost still remains a significant challenge. We report a scalable low cost method to synthesize Al/Na-doped and defect-abundant Si nanorods that have excellent electrochemical performance with high first-cycle Coulombic efficiency (90%). The unique Si nanorods are synthesized by acid etching the refined and rapidly solidified eutectic Al-Si ingot. To maintain the high electronic conductivity, a thin layer of carbon is then coated on the Si nanorods by carbonization of self-polymerized polydopamine (PDA) at 800 °C. The carbon coated Si nanorods (Si@C) electrode at 0.9 mg cm(-2) loading (corresponding to area-specific-capacity of ∼2.0 mAh cm(-2)) exhibits a reversible capacity of ∼2200 mAh g(-1) at 100 mA g(-1) current, and maintains ∼700 mAh g(-1) over 1000 cycles at 1000 mA g(-1) with a capacity decay rate of 0.02% per cycle. High Coulombic efficiencies of 87% in the first cycle and ∼99.7% after 5 cycles are achieved due to the formation of an artificial Al2O3 solid electrolyte interphase (SEI) on the Si surface, and the low surface area (31 m(2) g(-1)), which has never been reported before for nano-Si anodes. The excellent electrochemical performance results from the massive defects (twins, stacking faults, dislocations) and Al/Na doping in Si nanorods induced by rapid solidification and Na salt modifications; this greatly enhances the robustness of Si from the volume changes and alleviates the mechanical stress/strain of the Si nanorods during the lithium insertion/extraction process. Introducing massive defects and Al/Na doping in eutectic Si nanorods for Li-ion battery anodes is unexplored territory. We venture this uncharted territory to commercialize this nanostructured Si anode for the next generation of Li-ion batteries.

  4. Scalable Synthesis of Defect Abundant Si Nanorods for High-Performance Li-Ion Battery Anodes.

    PubMed

    Wang, Jing; Meng, Xiangcai; Fan, Xiulin; Zhang, Wenbo; Zhang, Hongyong; Wang, Chunsheng

    2015-06-23

    Microsized nanostructured silicon-carbon composite is a promising anode material for high energy Li-ion batteries. However, large-scale synthesis of high-performance nano-Si materials at a low cost still remains a significant challenge. We report a scalable low cost method to synthesize Al/Na-doped and defect-abundant Si nanorods that have excellent electrochemical performance with high first-cycle Coulombic efficiency (90%). The unique Si nanorods are synthesized by acid etching the refined and rapidly solidified eutectic Al-Si ingot. To maintain the high electronic conductivity, a thin layer of carbon is then coated on the Si nanorods by carbonization of self-polymerized polydopamine (PDA) at 800 °C. The carbon coated Si nanorods (Si@C) electrode at 0.9 mg cm(-2) loading (corresponding to area-specific-capacity of ∼2.0 mAh cm(-2)) exhibits a reversible capacity of ∼2200 mAh g(-1) at 100 mA g(-1) current, and maintains ∼700 mAh g(-1) over 1000 cycles at 1000 mA g(-1) with a capacity decay rate of 0.02% per cycle. High Coulombic efficiencies of 87% in the first cycle and ∼99.7% after 5 cycles are achieved due to the formation of an artificial Al2O3 solid electrolyte interphase (SEI) on the Si surface, and the low surface area (31 m(2) g(-1)), which has never been reported before for nano-Si anodes. The excellent electrochemical performance results from the massive defects (twins, stacking faults, dislocations) and Al/Na doping in Si nanorods induced by rapid solidification and Na salt modifications; this greatly enhances the robustness of Si from the volume changes and alleviates the mechanical stress/strain of the Si nanorods during the lithium insertion/extraction process. Introducing massive defects and Al/Na doping in eutectic Si nanorods for Li-ion battery anodes is unexplored territory. We venture this uncharted territory to commercialize this nanostructured Si anode for the next generation of Li-ion batteries. PMID:26014439

  5. High temperature behavior of zirconium germanates

    SciTech Connect

    Utkin, A.V.; Baklanova, N.I.; Vasilyeva, I.G.

    2013-05-01

    The high temperature behavior of zirconium germanates ZrGeO₄ and Zr₃GeO₈ up to 2300 °C has been studied using the original photoemission thermal analysis technique with the comprehensive physicochemical study of solid and gaseous intermediate and final products. The two-stage process of incongruent sublimation of GeO₂ was established and the phase boundary of the homogeneity range for ZrGeO₄ and Zr₃GeO₈ were deduced from the thermal analysis, X-ray diffraction and Raman spectroscopy studies. A high tendency to sintering of the final ZrO₂ product is discussed. - Graphical abstract: The decomposition of zirconium germanates leads to the formation of gaseous GeO₂ and solid sintered ZrO₂ and occurs via two stages with the formation of intermediate ZrO₂-rich solid solution. Highlights: •Thermal behavior of ZrGeO₄ and Zr₃GeO₈ was studied using the original thermal analysis technique in wide temperature range. •The decomposition occurs via two stages with the formation of intermediate ZrO₂-rich solid solution. •The decomposition of zirconium germanates leads to the formation of gaseous GeO₂ and solid sintered ZrO₂. •The temperature of decomposition is strongly depended on the total gas pressure.

  6. The NASA high temperature superconductivity program

    NASA Technical Reports Server (NTRS)

    Sokoloski, Martin M.; Romanofsky, Robert R.

    1990-01-01

    It has been recognized from the onset that high temperature superconductivity held great promise for major advances across a broad range of NASA interests. The current effort is organized around four key areas: communications and data, sensors and cryogenics, propulsion and power, and space materials technology. Recently, laser ablated YBa2Cu3O(7-x) films on LaAIO produced far superior RF characteristics when compared to metallic films on the same substrate. This achievement has enabled a number of unique microwave device applications, such as low insertion loss phase shifters and high Q filters. Melt texturing and melt quenched techniques are being used to produce bulk materials with optimized magnetic properties. These yttrium enriched materials possess enhanced flux pinning characteristics and will lead to prototype cryocooler bearings. Significant progress has also occurred in bolometer and current lead technology. Studies are being conducted to evaluate the effect of high temperature superconducting materials on the performance and life of high power magneto-plasma-dynamic thrusters. Extended studies were also performed to evaluate the benefit of superconducting magnetic energy storage for LEO space station, lunar and Mars mission applications. The project direction and level of effort of the program are also described.

  7. Structural application of high strength, high temperature ceramics

    NASA Technical Reports Server (NTRS)

    Hall, W. B.

    1982-01-01

    The operation of rocket engine turbine pumps is limited by the temperature restrictions of metallic components used in the systems. Mechanical strength and stability of these metallic components decrease drastically at elevated temperatures. Ceramic materials that retain high strength at high temperatures appear to be a feasible alternate material for use in the hot end of the turbopumps. This project identified and defined the processing parameters that affected the properties of Si3N4, one of candidate ceramic materials. Apparatus was assembled and put into operation to hot press Si3N4 powders into bulk material for in house evaluation. A work statement was completed to seek outside contract services to design, manufacture, and evaluate Si3N4 components in the service environments that exists in SSME turbopumps.

  8. High-Frequency, High-Temperature Fretting Experiments

    NASA Technical Reports Server (NTRS)

    Matlik, J. F.; Farris, T. N.; Haake, F. K.; Swanson, G. R.; Duke, G. C.

    2005-01-01

    Fretting is a structural damage mechanism observed when two nominally clamped surfaces are subjected to an oscillatory loading. A critical location for fretting induced damage has been identified at the blade/disk and blade/damper interfaces of gas turbine engine turbomachinery and space propulsion components. The high-temperature, high-frequency loading environment seen by these components lead to severe stress gradients at the edge-of-contact. These contact stresses drive crack nucleation and propagation in fretting and are very sensitive to the geometry of the contacting bodies, the contact loads, materials, temperature, and contact surface tribology (friction). To diagnose the threat that small and relatively undetectable fretting cracks pose to damage tolerance and structural integrity of in-service components, the objective of this work is to develop a well-characterized experimental fretting rig capable of investigating fretting behavior of advanced aerospace alloys subjected to load and temperature conditions representative of such turbomachinery components.

  9. High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems

    SciTech Connect

    Turnquist, Norman; Qi, Xuele; Raminosoa, Tsarafidy; Salas, Ken; Samudrala, Omprakash; Shah, Manoj; Van Dam, Jeremy; Yin, Weijun; Zia, Jalal

    2013-12-20

    This report summarizes the progress made during the April 01, 2010 – December 30, 2013 period under Cooperative Agreement DE-EE0002752 for the U.S. Department of Energy entitled “High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems.” The overall objective of this program is to advance the technology for well fluids lifting systems to meet the foreseeable pressure, temperature, and longevity needs of the Enhanced Geothermal Systems (EGS) industry for the coming ten years. In this program, lifting system requirements for EGS wells were established via consultation with industry experts and site visits. A number of artificial lift technologies were evaluated with regard to their applicability to EGS applications; it was determined that a system based on electric submersible pump (ESP) technology was best suited to EGS. Technical barriers were identified and a component-level technology development program was undertaken to address each barrier, with the most challenging being the development of a power-dense, small diameter motor that can operate reliably in a 300°C environment for up to three years. Some of the targeted individual component technologies include permanent magnet motor construction, high-temperature insulation, dielectrics, bearings, seals, thrust washers, and pump impellers/diffusers. Advances were also made in thermal management of electric motors. In addition to the overall system design for a full-scale EGS application, a subscale prototype was designed and fabricated. Like the full-scale design, the subscale prototype features a novel “flow-through-the-bore” permanent magnet electric motor that combines the use of high temperature materials with an internal cooling scheme that limits peak internal temperatures to <330°C. While the full-scale high-volume multi-stage pump is designed to lift up to 80 kg/s of process water, the subscale prototype is based on a production design that can pump 20 kg/s and has been modified

  10. High temperature NASP engine seal development

    NASA Astrophysics Data System (ADS)

    This video details research being conducted at the Lewis Research Center on high temperature engine seal design for the National Aerospace Plane. To maximize the speed, the jets on the NASP extract oxygen from the air rather than carry large liquid fuel tanks; this creates temperatures within the jet of over 5000 F. To prevent these potentially explosive gases from escaping, researchers are developing new technologies for use in the engine seals. Two examples explained are the ceramic wafer seal and the braided ceramic rope seal. Computer simulations and laboratory footage are used to illustrate the workings of these seals. Benefits for other aerospace and industrial applications, as well as for the space shuttle, are explored.

  11. Creep resistant high temperature martensitic steel

    SciTech Connect

    Hawk, Jeffrey A.; Jablonski, Paul D.; Cowen, Christopher J.

    2015-11-13

    The disclosure provides a creep resistant alloy having an overall composition comprised of iron, chromium, molybdenum, carbon, manganese, silicon, nickel, vanadium, niobium, nitrogen, tungsten, cobalt, tantalum, boron, and potentially additional elements. In an embodiment, the creep resistant alloy has a molybdenum equivalent Mo(eq) from 1.475 to 1.700 wt. % and a quantity (C+N) from 0.145 to 0.205. The overall composition ameliorates sources of microstructural instability such as coarsening of M.sub.23C.sub.6 carbides and MX precipitates, and mitigates or eliminates Laves and Z-phase formation. A creep resistant martensitic steel may be fabricated by preparing a melt comprised of the overall composition followed by at least austenizing and tempering. The creep resistant alloy exhibits improved high-temperature creep strength in the temperature environment of around 650.degree. C.

  12. High Temperature Battery for Drilling Applications

    SciTech Connect

    Josip Caja

    2009-12-31

    In this project rechargeable cells based on the high temperature electrochemical system Na/beta''-alumina/S(IV) in AlCl3/NaCl were developed for application as an autonomous power source in oil/gas deep drilling wells. The cells operate in the temperature range from 150 C to 250 C. A prototype DD size cell was designed and built based on the results of finite element analysis and vibration testing. The cell consisted of stainless steel case serving as anode compartment with cathode compartment installed in it and a seal closing the cell. Critical element in cell design and fabrication was hermetically sealing the cell. The seal had to be leak tight, thermally and vibration stable and compatible with electrode materials. Cathode compartment was built of beta''-alumina tube which served as an electrolyte, separator and cathode compartment.

  13. Heterogeneous metasurface for high temperature selective emission

    SciTech Connect

    Woolf, D. Hensley, J.; Cederberg, J. G.; Bethke, D. T.; Grine, A. D.; Shaner, E. A.

    2014-08-25

    We demonstrate selective emission from a heterogeneous metasurface that can survive repeated temperature cycling at 1300 K. Simulations, fabrication, and characterization were performed for a cross-over-a-backplane metasurface consisting of platinum and alumina layers on a sapphire substrate. The structure was stabilized for high temperature operation by an encapsulating alumina layer. The geometry was optimized for integration into a thermophotovoltaic (TPV) system, and was designed to have its emissivity matched to the external quantum efficiency spectrum of 0.6 eV InGaAs TPV material. We present spectral measurements of the metasurface that result in a predicted 22% optical-to-electrical power conversion efficiency in a simplified model at 1300 K. Furthermore, this broadly adaptable selective emitter design can be easily integrated into full-scale TPV systems.

  14. Permanent magnets composed of high temperature superconductors

    NASA Technical Reports Server (NTRS)

    Weinstein, Roy; Chen, In-Gann; Liu, Jay; Lau, Kwong

    1991-01-01

    A study of persistent, trapped magnetic field has been pursued with high-temperature superconducting (HTS) materials. The main effort is to study the feasibility of utilization of HTS to fabricate magnets for various devices. The trapped field, when not in saturation, is proportional to the applied field. Thus, it should be possible to replicate complicated field configurations with melt-textured YBa2Cu3O7 (MT-Y123) material, bypassing the need for HTS wires. Presently, materials have been developed from which magnets of 1.5 T, at 77 K, can be fabricated. Much higher field is available at lower operating temperature. Stability of a few percent per year is readily attainable. Results of studies on prototype motors and minimagnets are reported.

  15. Graphite thermal expansion reference for high temperature

    NASA Technical Reports Server (NTRS)

    Gaal, P. S.

    1974-01-01

    The design requirements of the aerospace and high-temperature nuclear reactor industries necessitate reliable thermal expansion data for graphite and other carbonaceous materials. The feasibility of an acceptable reference for calibration of expansion measuring systems that operate in carbon-rich atmospheres at temperatures ranging to 2500 C is the prime subject of this work. Present-day graphite technology provides acceptable materials for stable, reproducible references, as reflected by some of the candidate materials. The repeatability for a single specimen in a given expansion measuring system was found to be plus or minus 1%, while the combined results of several tests made on a number of samples fell within a plus or minus 2.5% band.

  16. Development of high temperature, high radiation resistant silicon semiconductors

    NASA Technical Reports Server (NTRS)

    Whorl, C. A.; Evans, A. W.

    1972-01-01

    The development of a hardened silicon power transistor for operation in severe nuclear radiation environments at high temperature was studied. Device hardness and diffusion techniques are discussed along with the geometries of hardened power transistor chips. Engineering drawings of 100 amp and 5 amp silicon devices are included.

  17. Fail Safe, High Temperature Magnetic Bearings

    NASA Technical Reports Server (NTRS)

    Minihan, Thomas; Palazzolo, Alan; Kim, Yeonkyu; Lei, Shu-Liang; Kenny, Andrew; Na, Uhn Joo; Tucker, Randy; Preuss, Jason; Hunt, Andrew; Carter, Bart; Kiraly, L. J. (Technical Monitor)

    2002-01-01

    This paper contributes to the magnetic bearing literature in two distinct areas: high temperature and redundant actuation. Design considerations and test results are given for the first published combined 538 C (1000 F) high speed rotating test performance of a magnetic bearing. Secondly, a significant extension of the flux isolation based, redundant actuator control algorithm is proposed to eliminate the prior deficiency of changing position stiffness after failure. The benefit of the novel extension was not experimentally demonstrated due to a high active stiffness requirement. In addition, test results are given for actuator failure tests at 399 C (750 F), 12,500 rpm. Finally, simulation results are presented confirming the experimental data and validating the redundant control algorithm.

  18. Rechargeable high-temperature batteries [Book Chapter

    SciTech Connect

    Cairns, Elton J.

    1981-01-01

    There has been growing research and development effort in the area of high-specific-energy, high-specific-power rechargeable batteries since the mid 1960s and it has been used in electric vehicles, electric utility networks, and solar- and wind-powered electric generator systems. Nonaqueous systems have been found to be the most attractive candidates for the above relatively large-scale applications. Only the high-temperature cells offer the attractive combination of features sought for the cited applications: a specific energy above 100 Wh/kg, a specific power above 100 W/kg, a cycle life in excess of 500 cycles (at 100% depth of discharge), and a projected cost of less than $50† per kWh of energy storage capability.

  19. Materials for high-temperature thermoelectric conversion

    NASA Technical Reports Server (NTRS)

    Feigelson, R. S.; Elwell, D.

    1983-01-01

    High boron materials of high efficiency for thermoelectric power generation and capable of prolonged operation at temperatures over 1200 C are discussed. Background theoretical studies indicated that the low carrier mobility of materials with beta boron and related structures is probably associated with the high density of traps. Experimental work was mainly concerned with silicon borides in view of promising data from European laboratories. A systematic study using structure determination and lattice constant measurements failed to confirm the existence of an SiBn phase. Only SiB6 and a solid solution of silicon in beta boron with a maximum solid solubility of 5.5-6 at % at 1650 C were found.

  20. High temperature deactivation of coal chars

    SciTech Connect

    Beeley, T.J.; Gibbins, J.R.; Man, C.K.

    1994-12-31

    High levels of char burnout, typically to less than 5% by weight of residual carbon in the fly ash, are desirable in large, multi-burner utility boilers fired with pulverised coal in order to optimise plant efficiency and allow the ash to be incorporated in building materials. Achieving high levels of char burnout can be a particular problem with air-staged low-NOx combustors, where air/fuel ratios (and flame temperatures) have to be constrained to give satisfactory emission levels. Switching to imported low-sulphur coals can also be associated with a need to at least assess the potential for burnout problems. In general the levels of carbon in ash required represent very high overall fuel conversion. For example, a coal with 10%w/w ash dry basis giving 5% carbon in ash will still achieve 99.4% conversion. The difference between satisfactory and unsatisfactory burnout thus depends on whether a very small fraction of the coal does or does not burn. This study examined the effect of time and temperature on char reactivity. Fly ash samples containing char were obtained from plant trials.

  1. Design Considerations for High Temperature Power Inductors

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.

    2005-01-01

    A uniform B-field approximation model is used to develop design formulas for single-layer wound, toroidal core, ac power inductors that must handle a specified current. Such a geometry is well suited for high temperature, high frequency inductors, where removal of heat from the core becomes critical. Explicit expressions are derived for core radii, core and winding volumes, winding turns and core permeability as functions of a dimensional scaling ratio (S). A limit on the maximum allowed core B-field leads to the result that the minimum core volume is proportional to the permeability, which has a lower bound. Plots versus S are provided for a specific case, to show that good designs can be picked in the overlap regions around the minima in mass and overall size, where the mass and size are relatively flat. Data to 250 C are presented for an MPP core based inductor to show that a quasi-linear, high temperature inductor can be constructed with available materials. A similar development is applied to a toroidal air-core geometry, showing that for the same ratings, such an inductor is considerably bigger and more massive, at least in the single-layer version.

  2. Perspectives on high temperature superconducting electronics

    NASA Technical Reports Server (NTRS)

    Venkatesan, T.

    1990-01-01

    The major challenges in making high temperature superconducting (HTSC) electronics viable are predominantly materials problems. Unlike their predecessors the metal oxide-based superconductors are integratable with other advanced technologies such as opto-electronics and micro-electronics. The materials problems to be addressed relate to the epitaxial growth of high quality films, highly oriented films on non-lattice matched substrates, heterostructures with atomically sharp interfaces of junctions and other novel devices, and the processing of these films with negligible deterioration of the superconducting properties. These issues are illustrated with results based on films prepared in-situ by a pulsed laser deposition process. Films with zero-transition temperatures of 90 K and critical current densities of 5 x 10(exp 6) A/sq cm at 77 K have been prepared by this technique. Ultra-thin films, less than 100 A show T(sub c) is greater than 80 K, supporting the idea of two-dimensional transport in these materials. By the use of appropriate buffer layers, films with T(sub c) of 87 K and J(sub c) of 6 x 10(exp 4) A/sq cm were fabricated on silicon substrates. Submicron structures with J(sub c) is greater than 2 x 10(exp 7) at 10 K were fabricated. Results on nonlinear switching elements, IR detectors, and microwave studies will be briefly summarized.

  3. Perspectives on high temperature superconducting electronics

    NASA Technical Reports Server (NTRS)

    Venkatesan, T.

    1991-01-01

    The major challenges in making high temperature superconducting (HTSC) electronics viable are predominantly materials problems. Unlike their predecessors, the metal oxide-based superconductors are integratable with other advanced technologies such as opto-electronics and micro-electronics. The materials problems to be addressed relate to the epitaxial growth of high quality films, highly oriented films on non-lattice matched substrates, heterostructures with atomically sharp interfaces of junctions and other novel devices, and the processing of these films with negligible deterioration of the superconducting properties. These issues are illustrated with results based on films prepared in-situ by a pulsed laser deposition process. Films with zero-transition temperatures of 90 K and critical current densities of 5 x 10(exp 6) A/sq cm at 77 K have been prepared by this technique. Ultra-thin films, less than 100 A show T(sub c) is greater than 80 K, supporting the idea of two-dimensional transport in these materials. By the use of appropriate buffer layers, films with T(sub c) of 87 K and J(sub c) of 6 x 10(exp 4) A/sq cm were fabricated on silicon substrates. Submicron structures with J(sub c) is greater than 2 x 10(exp 7) at 10 K were fabricated. Results on nonlinear switching elements, IR detectors, and microwave studies will be briefly summarized.

  4. High temperature barrier coatings for refractory metals

    NASA Technical Reports Server (NTRS)

    Malone, G. A.; Walech, T.

    1995-01-01

    Improvements in high temperature oxidation resistant metal coating technology will allow NASA and commercial entities to develop competitive civil space transport and communication systems. The success of investigations completed in this program will have a positive impact on broadening the technology base for high temperature materials. The work reported herein describes processes and procedures for successfully depositing coherent oxidation barrier coatings on refractory metals to prevent degradation under very severe operating environments. Application of the new technology developed is now being utilized in numerous Phase 3 applications through several prominent aerospace firms. Major achievements have included: (1) development of means to deposit thick platinum and rhodium coatings with lower stress and fewer microcracks than could be previously achieved; (2) development of processes to deposit thick adherent coatings of platinum group metals on refractory substrates that remain bonded through high temperature excursions and without need for intermediate coatings (bonding processes unique to specific refractory metals and alloys have been defined; (3) demonstration that useful alloys of refractory and platinum coatings can be made through thermal diffusion means; (4) demonstration that selected barrier coatings on refractory substrates can withstand severe oxidizing environments in the range of 1260 deg and 1760 deg C for long time periods essential to the life requirements of the hardware; and (5) successful application of the processes and procedures to prototype hardware. The results of these studies have been instrumental in improved thermal oxidation barrier coatings for the NASP propulsion system. Other Phase 3 applications currently being exploited include small uncooled thrusters for spacecraft and microsatellite maneuvering systems.

  5. An Ultra High Temperature Positive Photoresist

    NASA Astrophysics Data System (ADS)

    Grunwald, John; Turner, Edwin J.; Spencer, Allen C.; Sawoska, David A.; Ben-Shushan, Giyora

    1985-04-01

    This paper discusses the functional performance features of a new positive photoresist designated as ULTRAMAC' PR78T that can be subjected to temperatures up to 220°C. without any changes in the critical dimensions (CD's). No deep UV stabilization, intermediate post bakes, or other stabilization techniques are required to achieve high temperature thermal stability (220°C.). This high temperature positive photoresist is based on a diazo-coupled alkali soluble resin. The resolution and photospeed of this resist, ULTRAMAC' PR78T, are shown to be in the order of 1 micron using a 1.5 microns resist film thickness at 44 mJ/cm2. This resist also has submicron capabilities using step-and-repeat exposure equipment (10:1) utilizing monochromatic 436 nanometer light. ULTRAMAC' PR78T resist shows optimum sensitivity in the 300 - 500 nanometer UV spectral range. In contact or projection exposure equipment, resolution in the order of 1 micron can be achieved using a 1 micron resist film with exposure energies of about 35 mJ/cm2. For steppers using monochromatic light at 436 nanometers, typical exposure energies are in the order of 160 to 180 mJ/cm2, using either metal-ion-free or buffered metal based developers. Contrast (gamma) curves are shown for both metal-ion-free developer, ULTRAMAC' MF72A, and buffered metal containing developer, ULTRAMAC" D71A. High current ion implant data is also presented, showing no resist degradation. Anisotropic plasma/RIE etching selectivity data is also shown on SiO2 and aluminum alloy substrates.

  6. High temperature regenerable hydrogen sulfide removal agents

    DOEpatents

    Copeland, Robert J.

    1993-01-01

    A system for high temperature desulfurization of coal-derived gases using regenerable sorbents. One sorbent is stannic oxide (tin oxide, SnO.sub.2), the other sorbent is a metal oxide or mixed metal oxide such as zinc ferrite (ZnFe.sub.2 O.sub.4). Certain otherwise undesirable by-products, including hydrogen sulfide (H.sub.2 S) and sulfur dioxide (SO.sub.2) are reused by the system, and elemental sulfur is produced in the regeneration reaction. A system for refabricating the sorbent pellets is also described.

  7. High-Temperature, Oxidation-Resistant Thermocouples

    NASA Technical Reports Server (NTRS)

    Smialek, James L.; Gedwill, Michael A.

    1994-01-01

    Aluminum substituted for rhodium, which is scarce and expensive. Electromotive force increases with aluminum content in Pt/Al leg of Pt(Pt/Al) thermocouple. Wires baked longer in aluminizing bed produce larger voltages. Thermocouples containing platinum/aluminum legs used instead of thermocouples of type R in furnaces, heat engines, and chemical reactors. Expecially suited to high-velocity oxidizing environments. Constructed as thin-film sensors on turbine blades and vanes, where pre-oxidation provides insulating film needed between thermocouple legs. Because aluminum content slowly depleted by oxidation, long-term use recommended only where maximum temperature is 1,200 degrees C or less.

  8. Modeling forces in high-temperature superconductors

    SciTech Connect

    Turner, L. R.; Foster, M. W.

    1997-11-18

    We have developed a simple model that uses computed shielding currents to determine the forces acting on a high-temperature superconductor (HTS). The model has been applied to measurements of the force between HTS and permanent magnets (PM). Results show the expected hysteretic variation of force as the HTS moves first toward and then away from a permanent magnet, including the reversal of the sign of the force. Optimization of the shielding currents is carried out through a simulated annealing algorithm in a C++ program that repeatedly calls a commercial electromagnetic software code. Agreement with measured forces is encouraging.

  9. Development of high temperature gallium phosphide rectifiers

    NASA Technical Reports Server (NTRS)

    Craford, M. G.; Keune, D. L.

    1972-01-01

    Large area high performance, GaP rectifiers were fabricated by means of Zn diffusion into vapor phase epitaxial GaP. Devices with an active area of 0.01 sq cm typically exhibit forward voltages of 3 volts for a bias current of 1 ampere and have reverse breakdown voltages of 300 volts for temperatures from 27 C to 400 C. Typical device reverse saturation current at a reverse bias of 150 volts is less than 10 to the minus 9th power amp at 27 C and less than 0.000050 amp at 400 C.

  10. Search for new high temperature thermoelectric materials

    NASA Technical Reports Server (NTRS)

    Caillat, Thierry; Borshchevsky, Alex; Fleurial, Jean-Pierre

    1992-01-01

    Although important efforts are actually devoted to improve Si-Ge materials, their thermoelectric energy conversion efficiency remains relatively low and the nondimensional ZT value does not exceed 1. Higher values can be obtained by investigating new materials. A search for new high temperature thermoelectric materials identified a certain number of compounds between transition metals and bismuth, antimony and germanium as potential candidates. Results of the preliminary synthesis of samples by a variety of techniques (Bridgman, mechanical alloying) are presented as well as some electrical measurements. Some compounds showed interesting properties and need to be investigated in more details.

  11. Aerospace applications of high temperature superconductivity

    NASA Technical Reports Server (NTRS)

    Heinen, V. O.; Connolly, D. J.

    1991-01-01

    Space application of high temperature superconducting (HTS) materials may occur before most terrestrial applications because of the passive cooling possibilities in space and because of the economic feasibility of introducing an expensive new technology which has a significant system benefit in space. NASA Lewis Research Center has an ongoing program to develop space technology capitalizing on the potential benefit of HTS materials. The applications being pursued include space communications, power and propulsion systems, and magnetic bearings. In addition, NASA Lewis is pursuing materials research to improve the performance of HTS materials for space applications.

  12. Nickel oxide, ceramic insulated, high temperature coating

    SciTech Connect

    Aprigliano, L.F.

    1987-01-27

    This patent describes a corrosion, oxidation, and heat resistant layered coating for a substrate material in a high temperature, corrosive environment, consisting of: a base layer selected from the group consisting of Aluminide and MCrAlY, wherein M is a metal selected from the group consisting of nickel, cobalt, and a combination thereof; a ceramic layer, impermeable to the metallic elements of the substrate material and the MCrAlY layer, and bonded to the substrate material by the MCrAlY layer; and, a nickel oxide layer, applied to the ceramic layer.

  13. High temperature ion channels and pores

    NASA Technical Reports Server (NTRS)

    Kang, Xiaofeng (Inventor); Gu, Li Qun (Inventor); Cheley, Stephen (Inventor); Bayley, Hagan (Inventor)

    2011-01-01

    The present invention includes an apparatus, system and method for stochastic sensing of an analyte to a protein pore. The protein pore may be an engineer protein pore, such as an ion channel at temperatures above 55.degree. C. and even as high as near 100.degree. C. The analyte may be any reactive analyte, including chemical weapons, environmental toxins and pharmaceuticals. The analyte covalently bonds to the sensor element to produce a detectable electrical current signal. Possible signals include change in electrical current. Detection of the signal allows identification of the analyte and determination of its concentration in a sample solution. Multiple analytes present in the same solution may also be detected.

  14. High Temperature Materials Laboratory third annual report

    SciTech Connect

    Tennery, V.J.; Foust, F.M.

    1990-12-01

    The High Temperature Materials Laboratory has completed its third year of operation as a designated DOE User Facility at the Oak Ridge National Laboratory. Growth of the user program is evidenced by the number of outside institutions who have executed user agreements since the facility began operation in 1987. A total of 88 nonproprietary agreements (40 university and 48 industry) and 20 proprietary agreements (1 university, 19 industry) are now in effect. Sixty-eight nonproprietary research proposals (39 from university, 28 from industry, and 1 other government facility) and 8 proprietary proposals were considered during this reporting period. Research projects active in FY 1990 are summarized.

  15. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  16. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2011-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  17. Multichannel euv spectroscopy of high temperature plasmas

    SciTech Connect

    Fonck, R.J.

    1983-11-01

    Spectroscopy of magnetically confined high temperature plasmas in the visible through x-ray spectral ranges deals primarily with the study of impurity line radiation or continuum radiation. Detailed knowledge of absolute intensities, temporal behavior, and spatial distributions of the emitted radiation is desired. As tokamak facilities become more complex, larger, and less accessible, there has been an increased emphasis on developing new instrumentation to provide such information in a minimum number of discharges. The availability of spatially-imaging detectors for use in the vacuum ultraviolet region (especially the intensified photodiode array) has generated the development of a variety of multichannel spectrometers for applications on tokamak facilities.

  18. NEW APPROACHES: High temperature superconductors take off

    NASA Astrophysics Data System (ADS)

    Gough, Colin

    1998-01-01

    This article describes the progress made towards real engineering applications of high temperature superconductors (HTS) in the ten years following the Nobel Prize winning discovery by Bednorz and Müller in August 1986. Examples include HTS wires and tapes for more efficient and powerful electric motors and for increasing the electrical power into the heart of modern cities, HTS permanent magnets for levitation, microwave filters for cellular telephone networks, SQUIDs (superconducting quantum interference devices) to monitor foetal heart and brain signals, and a new generation of superfast logic devices based on the flux quantum.

  19. High temperature surface protection. [10 gas turbines

    NASA Technical Reports Server (NTRS)

    Levine, S. R.

    1978-01-01

    Alloys of the MCrAlX type are the basis for high temperature surface protection systems in gas turbines. M can be one or more of Ni, Co, or Fe and X denotes a reactive metal added to enhance oxide scale adherence. The selection and formation as well as the oxidation, hot corrosion and thermal fatigue performance of MCrAlX coatings are discussed. Coatings covered range from simple aluminides formed by pack cementation to the more advanced physical vapor deposition overlay coatings and developmental plasma spray deposited thermal barrier coatings.

  20. Spatial Mapping of Protein Abundances in the Mouse Brain by Voxelation Integrated with High-Throughput Liquid Chromatography - Mass Spectrometry

    SciTech Connect

    Petyuk, Vladislav A; Qian, Weijun; Chin, Mark H; Wang, Haixing H; Livesay, Eric A; Monroe, Matthew E; Adkins, Joshua N; Jaitly, Navdeep; Anderson, David J; Camp, David G; Smith, Desmond J; Smith, Richard D

    2007-01-25

    Temporally and spatially resolved mapping of protein abundance patterns within the mammalian brain is of significant interest for understanding brain function and molecular etiologies of neurodegenerative diseases; however, such imaging efforts have been greatly challenged by complexity of the proteome, throughput and sensitivity of applied analytical methodologies, and accurate quantitation of protein abundances across the brain. Here, we describe a methodology for comprehensive spatial proteome mapping that addresses these challenges by employing voxelation integrated with automated microscale sample processing, high-throughput LC system coupled with high resolution Fourier transform ion cyclotron mass spectrometer and a “universal” stable isotope labeled reference sample approach for robust quantitation. We applied this methodology as a proof-of-concept trial for the analysis of protein distribution within a single coronal slice of a C57BL/6J mouse brain. For relative quantitation of the protein abundances across the slice, an 18O-isotopically labeled reference sample, derived from a whole control coronal slice from another mouse, was spiked into each voxel sample and stable isotopic intensity ratios were used to obtain measures of relative protein abundances. In total, we generated maps of protein abundance patterns for 1,028 proteins. The significant agreement of the protein distributions with previously reported data supports the validity of this methodology, which opens new opportunities for studying the spatial brain proteome and its dynamics during the course of disease progression and other important biological and associated health aspects in a discovery-driven fashion.