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Sample records for niobium 88

  1. Process for recovering niobium from uranium-niobium alloys

    DOEpatents

    Wallace, Steven A.; Creech, Edward T.; Northcutt, Walter G.

    1983-01-01

    Niobium is recovered from scrap uranium-niobium alloy by melting the scrap with tin, solidifying the billet thus formed, heating the billet to combine niobium with tin therein, placing the billet in hydrochloric acid to dissolve the uranium and leave an insoluble residue of niobium stannide, then separating the niobium stannide from the acid.

  2. Process for recovering niobium from uranium-niobium alloys

    SciTech Connect

    Wallace, S.A.; Creech, E.T.; Northcutt, W.G.

    1983-11-01

    Niobium is recovered from scrap uranium-niobium alloy by melting the scrap with tin, solidifying the billet thus formed, heating the billet to combine niobium with tin therein, placing the billet in hydrochloric acid to dissolve the uranium and leave an insoluble residue of niobium stannide, then separating the niobium stannide from the acid.

  3. Passivated niobium cavities

    DOEpatents

    Myneni, Ganapati Rao; Hjorvarsson, Bjorgvin; Ciovati, Gianluigi

    2006-12-19

    A niobium cavity exhibiting high quality factors at high gradients is provided by treating a niobium cavity through a process comprising: 1) removing surface oxides by plasma etching or a similar process; 2) removing hydrogen or other gases absorbed in the bulk niobium by high temperature treatment of the cavity under ultra high vacuum to achieve hydrogen outgassing; and 3) assuring the long term chemical stability of the niobium cavity by applying a passivating layer of a superconducting material having a superconducting transition temperature higher than niobium thereby reducing losses from electron (cooper pair) scattering in the near surface region of the interior of the niobium cavity. According to a preferred embodiment, the passivating layer comprises niobium nitride (NbN) applied by reactive sputtering.

  4. Process for recovering niobium from uranium-niobium alloys

    DOEpatents

    Wallace, S.A.; Creech, E.T.; Northcutt, W.G.

    1982-09-27

    Niobium is recovered from scrap uranium-niobium alloy by melting the scrap with tin, solidifying the billet thus formed, heating the billet to combine niobium with tin therein, placing the billet in hydrochloric acid to dissolve the uranium and form a precipitate of niobium stannide, then separating the precipitate from the acid.

  5. Melting And Purification Of Niobium

    SciTech Connect

    Salles Moura, Hernane R.; Moura, Lourenco de

    2007-08-09

    The aspects involved in the purification of niobium in Electron Beam Furnaces will be outlined and correlated with practical experience accumulated over 17 years of continuously producing high purity niobium metal and niobium-zirconium ingots at CBMM, meeting the needs for a wide range of uses. This paper also reports some comments regarding raw material requirements, the experience on cold hearth operation melting niobium and the production of large grains niobium ingots by CBMM with some comments of their main characteristics.

  6. Melting And Purification Of Niobium

    NASA Astrophysics Data System (ADS)

    Moura, Hernane R. Salles; de Moura, Lourenço

    2007-08-01

    The aspects involved in the purification of niobium in Electron Beam Furnaces will be outlined and correlated with practical experience accumulated over 17 years of continuously producing high purity niobium metal and niobium-zirconium ingots at CBMM, meeting the needs for a wide range of uses. This paper also reports some comments regarding raw material requirements, the experience on cold hearth operation melting niobium and the production of large grains niobium ingots by CBMM with some comments of their main characteristics.

  7. Introduction to Ingot Niobium

    SciTech Connect

    Ganapati Rao Mynen, Andrew Hutton

    2011-03-01

    Superconducting radiofrequency (SRF) technology using niobium accelerating cavities was first applied at large scale in the recirculating electron linear accelerator CEBAF—the Continuous Electron Beam Accelerator Facility in Newport News, Virginia, USA, at what is now called Thomas Jefferson National Accelerator Facility, or Jefferson Lab. Building on the high quality factors and peak magnetic fields found in low residual resistivity ratio (low-RRR) solid niobium in the 1970s, Jefferson Lab has reintroduced ingot niobium technology. High tantalum content in ingot niobium is not expected to negatively impact cavity performance, but will reduce the cost of accelerator structures considerably. Optimized low-cost CW linear accelerators built with ingot niobium will show the way for future R&D and industrial applications. This paper portrays the Jefferson Lab SRF context, reviews the early history of ingot niobium technology from over a third of a century ago, explains the technical advantages of that technology's recent reintroduction, and presents the outlook for further development.

  8. Introduction to Ingot Niobium

    SciTech Connect

    Myneni, Ganapati Rao; Hutton, Andrew

    2011-03-31

    Superconducting radiofrequency (SRF) technology using niobium accelerating cavities was first applied at large scale in the recirculating electron linear accelerator CEBAF--the Continuous Electron Beam Accelerator Facility in Newport News, Virginia, USA, at what is now called Thomas Jefferson National Accelerator Facility, or Jefferson Lab. Building on the high quality factors and peak magnetic fields found in low residual resistivity ratio (low-RRR) solid niobium in the 1970s, Jefferson Lab has reintroduced ingot niobium technology. High tantalum content in ingot niobium is not expected to negatively impact cavity performance, but will reduce the cost of accelerator structures considerably. Optimized low-cost CW linear accelerators built with ingot niobium will show the way for future R and D and industrial applications. This paper portrays the Jefferson Lab SRF context, reviews the early history of ingot niobium technology from over a third of a century ago, explains the technical advantages of that technology's recent reintroduction, and presents the outlook for further development.

  9. Proton in SRF Niobium

    SciTech Connect

    Wallace, John Paul

    2011-03-31

    Hydrogen is a difficult impurity to physically deal with in superconducting radio frequency (SRF) niobium, therefore, its properties in the metals should be well understood to allow the metal's superconducting properties to be optimized for minimum loss in the construction of resonant accelerator cavities. It is known that hydrogen is a paramagnetic impurity in niobium from NMR studies. This paramagnetism and its effect on superconducting properties are important to understand. To that end analytical induction measurements aimed at isolating the magnetic properties of hydrogen in SRF niobium are introduced along with optical reflection spectroscopy which is also sensitive to the presence of hydrogen. From the variety, magnitude and rapid kinetics found in the optical and magnetic properties of niobium contaminated with hydrogen forced a search for an atomic model. This yielded quantum mechanical description that correctly generates the activation energy for diffusion of the proton and its isotopes not only in niobium but the remaining metals for which data is available. This interpretation provides a frame work for understanding the individual and collective behavior of protons in metals.

  10. Proton in SRF Niobium

    NASA Astrophysics Data System (ADS)

    Wallace, John Paul

    2011-03-01

    Hydrogen is a difficult impurity to physically deal with in superconducting radio frequency (SRF) niobium, therefore, its properties in the metals should be well understood to allow the metal's superconducting properties to be optimized for minimum loss in the construction of resonant accelerator cavities. It is known that hydrogen is a paramagnetic impurity in niobium from NMR studies. This paramagnetism and its effect on superconducting properties are important to understand. To that end analytical induction measurements aimed at isolating the magnetic properties of hydrogen in SRF niobium are introduced along with optical reflection spectroscopy which is also sensitive to the presence of hydrogen. From the variety, magnitude and rapid kinetics found in the optical and magnetic properties of niobium contaminated with hydrogen forced a search for an atomic model. This yielded quantum mechanical description that correctly generates the activation energy for diffusion of the proton and its isotopes not only in niobium but the remaining metals for which data is available. This interpretation provides a frame work for understanding the individual and collective behavior of protons in metals.

  11. METHOD OF PRODUCING NIOBIUM METAL

    DOEpatents

    Wilhelm, H.A.; Stevens, E.R.

    1960-05-24

    A process is given for preparing ductile niobium metal by the reduction of niobium pentoxide with carbon. The invention resides in the addition, to the reaction mass, of from 0.05 to 0.4 atom of titanium (in the form of metallic titanium, titanium carbide, and/or titanium oxide) per one mole of niobium pentoxide. The mixture is heated under subatmospheric pressure to above 1300 deg C but below the melting point of niobium, and the carbon- and oxygen-free niobium sponge obtained is cooled under reduced pressure.

  12. Method of surface preparation of niobium

    SciTech Connect

    Srinivasan-Rao, Triveni; Schill, John F.

    2003-01-01

    The present invention is for a method of preparing a surface of niobium. The preparation method includes polishing, cleaning, baking and irradiating the niobium surface whereby the resulting niobium surface has a high quantum efficiency.

  13. Vapor deposition of hardened niobium

    DOEpatents

    Blocher, Jr., John M.; Veigel, Neil D.; Landrigan, Richard B.

    1983-04-19

    A method of coating ceramic nuclear fuel particles containing a major amount of an actinide ceramic in which the particles are placed in a fluidized bed maintained at ca. 800.degree. to ca. 900.degree. C., and niobium pentachloride vapor and carbon tetrachloride vapor are led into the bed, whereby niobium metal is deposited on the particles and carbon is deposited interstitially within the niobium. Coating apparatus used in the method is also disclosed.

  14. Large grain cavities from pure niobium ingot

    DOEpatents

    Myneni, Ganapati Rao; Kneisel, Peter; Cameiro, Tadeu

    2012-03-06

    Niobium cavities are fabricated by the drawing and ironing of as cast niobium ingot slices rather than from cold rolled niobium sheet. This method results in the production of niobium cavities having a minimum of grain boundaries at a significantly reduced cost as compared to the production of such structures from cold rolled sheet.

  15. NIOBIUM-TANTALUM SEPARATION

    DOEpatents

    Wilhelm, H.A.; Foos, R.A.

    1959-01-27

    The usual method for the separation of tantalum and niobium consists of a selective solvent extraction from an aqueous hydrofluoric acid solution of the metals. A difficulty encountered in this process is the fact that the corrosion problems associated with hydrofluoric acid are serious. It has been found that the corrosion caused by the hydrofluoric acid may be substantially reduced by adding to the acidic solution an amine, such as phenyl diethanolamine or aniline, and adjusting pH value to between 4 and 6.

  16. Mechanical properties of niobium radio-frequency cavities

    DOE PAGESBeta

    Ciovati, Gianluigi; Dhakal, Pashupati; Matalevich, Joseph R.; Myneni, Ganapati Rao; Schmidt, A.; Iversen, J.; Matheisen, A.; Singer, W.

    2015-07-02

    Radio-frequency cavities made of bulk niobium are one of the components used in modern particle accelerators. The mechanical stability is an important aspect of cavity design, which typically relies on finite-element analysis simulations using material properties from tensile tests on sample. This contribution presents the results of strain and resonant frequency measurements as a function of a uniform pressure up to 722 kPa, applied to single-cell niobium cavities with different crystallographic structure, purity and treatments. In addition, burst tests of high-purity multi-cell cavities with different crystallographic structure have been conducted up to the tensile strength of the material. Finite-element analysismore » of the single-cell cavity geometry is in good agreement with the observed behavior in the elastic regime assuming a Young's modulus value of 88.5 GPa and a Poisson's ratio of 0.4, regardless of crystallographic structure, purity or treatment. However, the measured yield strength and tensile strength depend on crystallographic structure, material purity and treatment. In particular, the results from this study show that the mechanical properties of niobium cavities with large crystals are comparable to those of cavities made of fine-grain niobium.« less

  17. Mechanical properties of niobium radio-frequency cavities

    SciTech Connect

    Ciovati, Gianluigi; Dhakal, Pashupati; Matalevich, Joseph R.; Myneni, Ganapati Rao; Schmidt, A.; Iversen, J.; Matheisen, A.; Singer, W.

    2015-07-02

    Radio-frequency cavities made of bulk niobium are one of the components used in modern particle accelerators. The mechanical stability is an important aspect of cavity design, which typically relies on finite-element analysis simulations using material properties from tensile tests on sample. This contribution presents the results of strain and resonant frequency measurements as a function of a uniform pressure up to 722 kPa, applied to single-cell niobium cavities with different crystallographic structure, purity and treatments. In addition, burst tests of high-purity multi-cell cavities with different crystallographic structure have been conducted up to the tensile strength of the material. Finite-element analysis of the single-cell cavity geometry is in good agreement with the observed behavior in the elastic regime assuming a Young's modulus value of 88.5 GPa and a Poisson's ratio of 0.4, regardless of crystallographic structure, purity or treatment. However, the measured yield strength and tensile strength depend on crystallographic structure, material purity and treatment. In particular, the results from this study show that the mechanical properties of niobium cavities with large crystals are comparable to those of cavities made of fine-grain niobium.

  18. Niobium Production at Tokyo Denkai

    SciTech Connect

    Umezawa, Hiroaki

    2011-03-31

    In recent years, single-crystal/large-grain niobium has received much attention. It has the following advantages: rolling-annealing is unnecessary, and superconducting cavities made from large-grain niobium discs may not require electropolishing. However, to obtain a large-grain disc, an ingot must be sliced using a saw and finished smooth by using a lathe. Slicing a disc takes several hours and produces niobium shavings. KEK, Tokyo Denkai, and TKX Corporation have developed a new niobium ingot slicing technique, and Tokyo Denkai has installed the slicing machine. This study describes the new ingot slicing technology, which ensures state-of-the-art productivity for the superconducting radio frequency (SRF) cavity material industry.

  19. Niobium and tantalum: indispensable twins

    USGS Publications Warehouse

    Schulz, Klaus; Papp, John

    2014-01-01

    Niobium and tantalum are transition metals almost always paired together in nature. These “twins” are difficult to separate because of their shared physical and chemical properties. In 1801, English chemist Charles Hatchett uncovered an unknown element in a mineral sample of columbite; John Winthrop found the sample in a Massachusetts mine and sent it to the British Museum in London in 1734. The name columbium, which Hatchet named the new element, came from the poetic name for North America—Columbia—and was used interchangeably for niobium until 1949, when the name niobium became official. Swedish scientist Anders Ekberg discovered tantalum in 1802, but it was confused with niobium, because of their twinned properties, until 1864, when it was recognized as a separate element. Niobium is a lustrous, gray, ductile metal with a high melting point, relatively low density, and superconductor properties. Tantalum is a dark blue-gray, dense, ductile, very hard, and easily fabricated metal. It is highly conductive to heat and electricity and renowned for its resistance to acidic corrosion. These special properties determine their primary uses and make niobium and tantalum indispensable.

  20. METHOD FOR COATING GRAPHITE WITH NIOBIUM CARBIDE

    DOEpatents

    Kane, J.S.; Carpenter, J.H.; Krikorian, O.H.

    1962-01-16

    A method is given for coating graphite with a hard, tenacious layer of niobium carbide up to 30 mils or more thick. The method makes use of the discovery that niobium metal, if degassed and heated rapidly below the carburization temperature in contact with graphite, spreads, wets, and penetrates the graphite without carburization. The method includes the obvious steps of physically contacting niobium powders or other physical forms of niobium with graphite, degassing the assembly below the niobium melting point, e.g., 1400 deg C, heating to about 2200 to 2400 deg C within about 15 minutes while outgassing at a high volume throughput, and thereafter carburizing the niobium. (AEC)

  1. Direct Flotation of Niobium Oxide Minerals from Carbonatite Niobium Ores

    NASA Astrophysics Data System (ADS)

    Ni, Xiao

    Currently the recovery of niobium oxide minerals from carbonatite niobium ores relies on the use of non-selective cationic collectors. This leads to complicated process flowsheets involving multiple desliming and multiple reverse flotation stages, and low niobium recovery. In this research, anionic collectors that are capable of strong chemisorption on the niobium minerals were studied with the objective of directly floating the niobium oxide minerals from the carbonatite ores. In the flotation of both high purity minerals and Niobec ores, it was shown that the combination of hydroxamic acid and sodium metaphosphate was an effective reagent scheme for the direct flotation of niobium oxide from its ores. Batch flotation on the Niobec Mill Feed showed that over 95% of niobium oxide was recovered into a rougher concentrate that was less than 47% of the original feed mass. Preliminary cleaning tests showed that the reagent scheme could also be used to upgrade the rougher concentrate, although the depression of iron oxide minerals required further study. X-ray photoelectron spectroscopic (XPS) measurement results confirm that OHA (octyl hydroxamic acid) could chemisorb on pyrochlore surface while only physically adsorb on calcite, judging by the chemical shifts of electron binding energies in the elements in both OHA and the mineral surfaces. When hydroxamic acid was adsorbed on calcite surface, the binding energies of the N 1s electrons, at 400.3 eV, did not shift. However, after adsorption on pyrochlore, the N 1s binding energy peak split into two peaks, one at a binding energy of around 399 eV, representing chemically adsorbed OHA, the other at between 400 and 401 eV. The experimental data suggested a strong chemisorption of the OHA on pyrochlore surface in the form of a vertical head-on orientation of the OHA molecules so that the pyrochlore was strongly hydrophobized even at low OHA concentrations, followed by possibly randomly oriented physisorbed OHA molecules

  2. Niobium - Proceedings of the international symposium

    SciTech Connect

    Stuart, H.

    1984-01-01

    This book presents the papers given at a symposium on niobium. Topics considered at the symposium included niobium mining, ore processing, uses, fabrication, microstructure, mechanical properties, physical properties, corrosion, physical radiation effects, and marketing.

  3. Preparation of cubic niobium pyrophosphate containing Nb(IV) and topatactic extraction of phosphorus atoms

    SciTech Connect

    Fukuoka, Hiroshi; Imoto, Hideo; Saito, Taro

    1995-10-01

    A reduced phase of niobium pyrophosphate containing Nb{sup 4+} has been prepared from the reaction of Nb{sup 6}Cl{sub 14}{center_dot}8H{sub 2}O and phosphoric acid. The X-ray powder diffraction and electron diffraction studies have shown that the compound belongs to the Pa3 space group and has the ZrP{sub 2}O{sub 7} structure with a cubic superstructure (a{prime} = 3a{sub 0}). Magnetic susceptibility was measured for two samples, and the mean oxidation numbers of niobium in them are deduced to by + 4.66 and +4.88. The cell constants of these samples are a = 8.0830(4) and 8.0705(2) {angstrom}, respectively. As the mean oxidation number of niobium increases, the color of the compound varies from brown to gray. When the compound is heated in oxygen, it changes into the known white niobium pyrophosphate, in which all niobium is in the +5 oxidation state. Rietveld refinements indicate that niobium pyrophosphates have defects in the phosphorus sites. The topotactic extraction of the phosphorus atoms in the reaction with oxygen was confirmed by the analysis of phosphorus oxide generated during the reaction.

  4. Spectrophotometric determination of niobium and its application to niobium-stabilized stainless steel.

    PubMed

    Dutta, R K; Banerjee, S

    1974-10-01

    A spectrophotometric method is described for the determination of niobium by means of its reaction with tannin and thioglycollic acid. The yellow-orange colour developed with the reagent mixture at pH 4 is measured at 410-420 nm and obeys Beer's law between 0.5 and 10 ppm niobium. The method is suitable for the determination of niobium in niobium-stabilized stainless steel and other types of steels containing niobium, but a prior separation of niobium is necessary. Titanium interferes even in traces. PMID:18961571

  5. STS-88 Crew Portrait

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Five NASA astronauts and a Russian cosmonaut assigned to the STS-88 mission pose for a crew portrait. Seated in front (left to right) are mission specialists Sergei K. Krikalev, representing the Russian Space Agency (RSA), and astronaut Nancy J. Currie. In the rear from the left, are astronauts Jerry L. Ross, mission specialist; Robert D. Cabana, mission commander; Frederick W. 'Rick' Sturckow, pilot; and James H. Newman, mission specialist. The STS-88 mission launched aboard the Space Shuttle Endeavor on December 4, 1998 at 2:35 a.m. (CST) to deliver the Unity Node to the International Space Station (ISS).

  6. Superconductive niobium films coating carbon nanotube fibers

    NASA Astrophysics Data System (ADS)

    Salvato, M.; Lucci, M.; Ottaviani, I.; Cirillo, M.; Behabtu, N.; Young, C. C.; Pasquali, M.; Vecchione, A.; Fittipaldi, R.; Corato, V.

    2014-11-01

    Superconducting niobium (Nb) has been successfully obtained by sputter deposition on carbon nanotube fibers. The transport properties of the niobium coating the fibers are compared to those of niobium thin films deposited on oxidized Si substrates during the same deposition run. For niobium films with thicknesses above 300 nm, the niobium coating the fibers and the thin films show similar normal state and superconducting properties with critical current density, measured at T = 4.2 K, of the order of 105 A cm-2. Thinner niobium layers coating the fibers also show the onset of the superconducting transition in the resistivity versus temperature dependence, but zero resistance is not observed down to T = 1 K. We evidence by scanning electron microscopy (SEM) and current-voltage measurements that the granular structure of the samples is the main reason for the lack of true global superconductivity for thicknesses below 300 nm.

  7. Dissipative hydride precipitates in superconducting niobium cavities

    SciTech Connect

    Romanenko, A.; Cooley, L.D.; Ciovati, G.; Wu, G.; /Argonne

    2011-10-01

    We report the first direct observation of the microstructural features exhibiting RF losses at high surface magnetic fields of above 100 mT in field emission free superconducting niobium cavities. The lossy areas were identified by advanced thermometry. Surface investigations using different techniques were carried out on cutout samples from lossy areas and showed the presence of dendritic niobium hydrides. This finding has possible implications to the mechanisms of RF losses in superconducting niobium at all field levels.

  8. Process for alloying uranium and niobium

    DOEpatents

    Holcombe, Cressie E.; Northcutt, Jr., Walter G.; Masters, David R.; Chapman, Lloyd R.

    1991-01-01

    Alloys such as U-6Nb are prepared by forming a stacked sandwich array of uraniun sheets and niobium powder disposed in layers between the sheets, heating the array in a vacuum induction melting furnace to a temperature such as to melt the uranium, holding the resulting mixture at a temperature above the melting point of uranium until the niobium dissolves in the uranium, and casting the uranium-niobium solution. Compositional uniformity in the alloy product is enabled by use of the sandwich structure of uranium sheets and niobium powder.

  9. Niobium content of soils from West Africa

    USGS Publications Warehouse

    Grimaldi, F.S.; Berger, I.A.

    1961-01-01

    Analysis of twenty lateritic soil samples from West Africa has shown them to contain an average 24 p.p.m. of niobium; four similar samples taken from within a few miles from a niobium deposit contain from 79 to 87 p.p.m. niobium. It has been shown that as the aluminum content of the soils increases, the following depletion sequence is obtained: Si > Nb > Al = Fe The data indicate that, in general, high enrichments of niobium are not to be expected in lateritic soils. ?? 1961.

  10. Process for alloying uranium and niobium

    SciTech Connect

    Holcombe, C.E.; Northcutt, W.G.; Masters, D.R.; Chapman, L.R.

    1990-12-31

    Alloys such as U-6Nb are prepared by forming a stacked sandwich array of uranium sheets and niobium powder disposed in layers between the sheets, heating the array in a vacuum induction melting furnace to a temperature such as to melt the uranium, holding the resulting mixture at a temperature above the melting point of uranium until the niobium dissolves in the uranium, and casting the uranium-niobium solution. Compositional uniformity in the alloy product is enabled by use of the sandwich structure of uranium sheets and niobium powder.

  11. Seamless/bonded niobium cavities

    NASA Astrophysics Data System (ADS)

    Singer, W.

    2006-07-01

    Technological aspects and performance of seamless cavities produced by hydroforming are presented. Problems related to the fabrication of seamless cavities from bulk niobium are mainly solved thanks to the progress of the last years. The highest achieved accelerating gradients are comparable for both seamless and welded versions (ca. 40 MV/m) Nevertheless further development of seamless cavities is desirable in order to avoid the careful preparation of parts for welding and get reliable statistic. Fabrication of NbCu clad cavities from bimetallic tubes is an interesting option that gives new opportunity to the seamless technique. On the one hand it allows reducing the niobium costs contribution; on the other hand it increases the thermal stability of the cavity. The highest accelerating gradient achieved on seamless NbCu clad single cell cavities (ca. 40 MV/m) is comparable to the one reached on bulk Nb cavities. Fabrication of multi-cell NbCu cavities by hydroforming was recently proven.

  12. SRF MATERIALS OTHER THAN NIOBIUM

    SciTech Connect

    Valente, Anne-Marie

    2008-02-12

    For the past three decades, bulk niobium has been the material of choice for SRF cavity applications. Alternative materials, mainly Nb compounds and A15 compounds have been investigated with moderate effort in the past. In the recent years, RF cavity performance has approached the theoretical limit for bulk niobium. For further improvement of RF cavity performance for future accelerator projects, research interest is renewed towards alternative materials to niobium. A few laboratories around the world are now investigating superconductors with higher transition temperature Tc for application to SRF cavities. This paper gives an overview of the results obtained and challenges encountered for Nb compounds and A15 compounds, as well as for MgB2, for SRF cavity applications. An interesting alternative has been recently proposed by Alex Gurevich with the Superconductor-Insulator-Superconductor multilayer approach. This could potentially lead to further improvement in RF cavity performance using the benefit of the higher critical field Hc of higher-Tc superconductors without being limited with their lower Hc1.

  13. Urban Water '88

    NASA Astrophysics Data System (ADS)

    Zuidena, Floris C.; Hoogart, Hans

    The Symposium on Hydrological Processes and Water Management in Urban Areas (Urban Water '88) was held in Duisburg, West Germany, and The Netherlands, April 24-29, 1988. Six themes were discussed during the 3-day conference and 2-day study tour: urban hydrological cycle, functions and uses of water, concepts of urban drainage and flood protection, effects of urbanization on surface and groundwater, and the role of water in city planning and integrated water management in urban areas.

  14. Purification of Niobium by Electron Beam Melting

    NASA Astrophysics Data System (ADS)

    Sankar, M.; Mirji, K. V.; Prasad, V. V. Satya; Baligidad, R. G.; Gokhale, A. A.

    2016-06-01

    Pure niobium metal, produced by alumino-thermic reduction of niobium oxide, contains various impurities which need to be reduced to acceptable levels to obtain aerospace grade purity. In the present work, an attempt has been made to refine niobium metals by electron beam drip melting technique to achieve purity confirming to the ASTM standard. Input power to the electron gun and melt rate were varied to observe their combined effect on extend of refining and loss of niobium. Electron beam (EB) melting is shown to reduce alkali metals, trace elements and interstitial impurities well below the specified limits. The reduction in the impurities during EB melting is attributed to evaporation and degassing due to the combined effect of high vacuum and high melt surface temperature. The % removal of interstitial impurities is essentially a function of melt rate and input power. As the melt rate decreases or input power increases, the impurity levels in the solidified niobium ingot decrease. The EB refining process is also accompanied by considerable amount of niobium loss, which is attributed to evaporation of pure niobium and niobium sub-oxide. Like other impurities, Nb loss increases with decreasing melt rate or increase in input power.

  15. Method of nitriding niobium to form a superconducting surface

    DOEpatents

    Kelley, Michael J.; Klopf, John Michael; Singaravelu, Senthilaraja

    2014-08-19

    A method of forming a delta niobium nitride .delta.-NbN layer on the surface of a niobium object including cleaning the surface of the niobium object; providing a treatment chamber; placing the niobium object in the treatment chamber; evacuating the chamber; passing pure nitrogen into the treatment chamber; focusing a laser spot on the niobium object; delivering laser fluences at the laser spot until the surface of the niobium object reaches above its boiling temperature; and rastering the laser spot over the surface of the niobium object.

  16. STS-88 Mission Insignia

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Designed by the STS-88 crew members, this patch commemorates the first assembly flight to carry United States-built hardware for constructing the International Space Station (ISS). This flight's primary task was to assemble the cornerstone of the Space Station: the Node with the Functional Cargo Block (FGB). The rising sun symbolizes the dawning of a new era of international cooperation in space and the beginning of a new program: the International Space Station. The Earth scene outlines the countries of the Station Partners: the United States, Russia, those of the European Space Agency (ESA), Japan, and Canada. Along with the Pressurized Mating Adapters (PMA) and the Functional Cargo Block, the Node is shown in the final mated configuration while berthed to the Space Shuttle during the STS-88/2A mission. The Big Dipper Constellation points the way to the North Star, a guiding light for pioneers and explorers for generations. In the words of the crew, These stars symbolize the efforts of everyone, including all the countries involved in the design and construction of the International Space Station, guiding us into the future.

  17. Buffered Electrochemical Polishing of Niobium

    SciTech Connect

    Gianluigi Ciovati; Tian, Hui; Corcoran, Sean

    2011-03-01

    The standard preparation of superconducting radio-frequency (SRF) cavities made of pure niobium include the removal of a 'damaged' surface layer, by buffered chemical polishing (BCP) or electropolishing (EP), after the cavities are formed. The performance of the cavities is characterized by a sharp degradation of the quality factor when the surface magnetic field exceeds about 90 mT, a phenomenon referred to as 'Q-drop.' In cavities made of polycrystalline fine grain (ASTM 5) niobium, the Q-drop can be significantly reduced by a low-temperature (? 120 °C) 'in-situ' baking of the cavity if the chemical treatment was EP rather than BCP. As part of the effort to understand this phenomenon, we investigated the effect of introducing a polarization potential during buffered chemical polishing, creating a process which is between the standard BCP and EP. While preliminary results on the application of this process to Nb cavities have been previously reported, in this contribution we focus on the characterization of this novel electrochemical process by measuring polarization curves, etching rates, surface finish, electrochemical impedance and the effects of temperature and electrolyte composition. In particular, it is shown that the anodic potential of Nb during BCP reduces the etching rate and improves the surface finish.

  18. A Terminally Bound Niobium Methylidyne.

    PubMed

    Kurogi, Takashi; Carroll, Patrick J; Mindiola, Daniel J

    2016-04-01

    Complex (PNP)Nb(CH3)2(OAr) (PNP = N[2-P(i)Pr2-4-methylphenyl]2(-), Ar = 2,6-(i)Pr2C6H3), prepared from treatment of (PNP)NbCl3 with NaOAr followed by 2 equiv of H3CMgCl, can be oxidized with [FeCp2][OTf] to afford (PNP)Nb(CH3)2(OAr)(OTf). While photolysis of the latter resulted in formation of a rare example of a niobium methylidene, (PNP)Nb═CH2(OAr)(OTf), treatment of the dimethyl triflate precursor with the ylide H2CPPh3 produced the mononuclear group 5 methylidyne complex, (PNP)Nb≡CH(OAr). Adding a Brønsted base to (PNP)Nb═CH2(OAr)(OTf) also resulted in formation of the methylidyne. Solid-state structural analysis confirms both methylidene and methylidyne moieties to be terminal, having very short Nb-C distances of 1.963(2) and 1.820(2) Å, respectively. It is also shown that methylidyne for nitride cross-metathesis between (PNP)Nb≡CH(OAr) and NCR (R = tert-butyl or 1-adamantyl) results in formation of a neutral and mononuclear niobium nitride, (PNP)Nb≡N(OAr), along with the terminal alkyne HC≡CR. PMID:26977892

  19. Method for etching thin films of niobium and niobium-containing compounds for preparing superconductive circuits

    DOEpatents

    Kampwirth, Robert T.; Schuller, Ivan K.; Falco, Charles M.

    1981-01-01

    An improved method of preparing thin film superconducting electrical circuits of niobium or niobium compounds in which a thin film of the niobium or niobium compound is applied to a nonconductive substrate, and covered with a layer of photosensitive material. The sensitive material is in turn covered with a circuit pattern exposed and developed to form a mask of the circuit in photoresistive material on the surface of the film. The unmasked excess niobium film is removed by contacting the substrate with an aqueous etching solution of nitric acid, sulfuric acid and hydrogen fluoride, which will rapidly etch the niobium compound without undercutting the photoresist. A modification of the etching solution will permit thin films to be lifted from the substrate without further etching.

  20. The oxidation behavior and protection of niobium

    NASA Astrophysics Data System (ADS)

    Perkins, Roger A.; Meier, Gerald H.

    1990-08-01

    Despite years of effort, researchers have been unable to develop a high-temperature niobium-base alloy with the ability to form a protective oxide scale. Although some of the alloys tested have potentially useful properties, the alloying elements usually act to the detriment of at least one property. Currently, niobium-base alloys are protected from high-temperature oxidation with a highly reliable silicide coating. This article reviews the efforts to develop oxidation-resistant alloys and summarizes the results of recent research on oxidation-resistant niobium-base intermetallics.

  1. Degreasing and cleaning superconducting RF Niobium cavities

    SciTech Connect

    Rauchmiller, Michael; Kellett, Ron; /Fermilab

    2011-09-01

    The purpose and scope of this report is to detail the steps necessary for degreasing and cleaning of superconducting RF Niobium cavities in the A0 clean room. It lists the required equipment and the cleaning procedure.

  2. Effect of hydrogen on surface of niobium

    SciTech Connect

    Gadgil, V.J.; Keim, E.G.

    1998-12-31

    Niobium single crystals are used as substrate material for constructing superconducting quantum interference device of SQUID. The use of niobium is prompted by the fact that it is a low {Tc} metallic superconductor. In order to fabricate the device the surface of the crystal has to be polished flat. This is achieved by combination of mechanical polishing and electrochemical polishing. It has been reported that during electrochemical polishing hydrogen can enter the material forming Niobium hydrides. These can result in surface roughening of a magnitude greater than the thickness of the films subsequently deposited. This leads to failure of the films. The problem can be solved by annealing the material at 300 C to remove any hydrogen that might be present. However it is phenomenologically interesting to study the effect of electrochemical hydrogen charging on the surface of Niobium.

  3. Recovery of niobium from irradiated targets

    SciTech Connect

    Phillips, D.R.; Jamriska, D.J. Sr.; Hamilton, V.T.

    1994-03-22

    A process for selective separation of niobium from proton irradiated molybdenum targets is provided and includes dissolving the molybdenum target in a hydrogen peroxide solution to form a first ion-containing solution, contacting the first ion-containing solution with a cationic resin whereby ions selected form the group consisting of molybdenum, niobium, technetium, selenium, vanadium, arsenic, germanium, zirconium and rubidium remain in a second ion-containing solution while ions selected from the group consisting of rubidium, zinc, beryllium, cobalt, iron, manganese, chromium, strontium, yttrium and zirconium are selectively adsorbed by the cationic resin; adjusting the pH of the second ion-containing solution to within a range of from about 5.0 to about 6.0; contacting the pH adjusting second ion-containing solution with a dextran-based material for a time to selectively separate niobium from the solution and recovering the niobium from the dextran-based material.

  4. Mineral Resource of the Month: Niobium

    USGS Publications Warehouse

    Papp, John F.

    2014-01-01

    Niobium, also called columbium, is a transition metal with a very high melting point. It is in greatest demand in industrialized countries, like the United States, because of its defense-related uses in the aerospace, energy and transportation industries. Niobium is used mostly to make high-strength, low-alloy (HSLA) steel and stainless steel. HSLA steels are used in large-diameter pipes for oil and natural gas pipelines and automobile wheels.

  5. Mineral resource of the month: niobium (columbium)

    USGS Publications Warehouse

    Papp, John F.

    2007-01-01

    It’s not just diamonds associated with conflict in Africa. Coltan, short for columbite-tantalite (a blend of niobium — also called columbium — and tantalum minerals), is linked with the recent conflicts in the Congo that involved several African countries. The metallic ore, which is processed to separate out niobium and the very valuable tantalum (see Geotimes, August 2004), is believed to be smuggled out and sold to help finance the armed conflicts.

  6. Niobium based coatings for dental implants

    NASA Astrophysics Data System (ADS)

    Ramírez, G.; Rodil, S. E.; Arzate, H.; Muhl, S.; Olaya, J. J.

    2011-01-01

    Niobium based thin films were deposited on stainless steel (SS) substrates to evaluate them as possible biocompatible surfaces that might improve the biocompatibility and extend the life time of stainless steel dental implants. Niobium nitride and niobium oxide thin films were deposited by reactive unbalanced magnetron sputtering under standard deposition conditions without substrate bias or heating. The biocompatibility of the surfaces was evaluated by testing the cellular adhesion and viability/proliferation of human cementoblasts during different culture times, up to 7 days. The response of the films was compared to the bare substrate and pieces of Ti6Al4V; the most commonly used implant material for orthopedics and osteo-synthesis applications. The physicochemical properties of the films were evaluated by different means; X-ray diffraction, Rutherford backscattering spectroscopy and contact angle measurements. The results suggested that the niobium oxide films were amorphous and of stoichiometric Nb2O5 (a-Nb2O5), while the niobium nitride films were crystalline in the FCC phase (c-NbN) and were also stoichiometric with an Nb to N ratio of one. The biological evaluation showed that the biocompatibility of the SS could be improved by any of the two films, but neither was better than the Ti6Al4V alloy. On the other hand, comparing the two films, the c-NbN seemed to be a better surface than the oxide in terms of the adhesion and proliferation of human cemetoblasts.

  7. 40 CFR 721.10602 - Lead niobium titanium zirconium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Lead niobium titanium zirconium oxide... Specific Chemical Substances § 721.10602 Lead niobium titanium zirconium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lead niobium...

  8. 40 CFR 721.10602 - Lead niobium titanium zirconium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Lead niobium titanium zirconium oxide... Specific Chemical Substances § 721.10602 Lead niobium titanium zirconium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lead niobium...

  9. Recovery of niobium from irradiated targets

    DOEpatents

    Phillips, Dennis R.; Jamriska, Sr., David J.; Hamilton, Virginia T.

    1994-01-01

    A process for selective separation of niobium from proton irradiated molybdenum targets is provided and includes dissolving the molybdenum target in a hydrogen peroxide solution to form a first ion-containing solution, contacting the first ion-containing solution with a cationic resin whereby ions selected form the group consisting of molybdenum, biobium, technetium, selenium, vanadium, arsenic, germanium, zirconium and rubidium remain in a second ion-containing solution while ions selected from the group consisting of rubidium, zinc, beryllium, cobalt, iron, manganese, chromium, strontium, yttrium and zirconium are selectively adsorbed by the cationic resin; adjusting the pH of the second ion-containing solution to within a range of from about 5.0 to about 6.0; contacting the pH adjusting second ion-containing solution with a dextran-based material for a time to selectively separate niobium from the solution and recovering the niobium from the dextran-based material.

  10. Production of High Purity Niobium Ingots at CBMM

    SciTech Connect

    Moura, Lourenco de; Faria Sousa, Clovis Antonio de; Burgos Cruz, Edmundo

    2011-03-31

    CBMM is a fully integrated company, from the mine to the end line of the production chain, supplying different niobium products to the world market: ferroniobium, nickelniobium, niobium pentoxide and high purity metallic niobium. This high purity metallic niobium has long been known to exhibit superconductivity below 9.25 Kelvin. This characteristic has the potential to bring technological benefits for many different areas such as medicine, computing and environment. This paper presents the raw material requirements as well as CBMM experience on producing high purity niobium ingots. The results prove that CBMM material can be the best solution for special applications such as low cost superconductive radiofrequency cavities.

  11. PURE NIOBIUM AS A PRESSURE VESSEL MATERIAL

    SciTech Connect

    Peterson, T. J.; Carter, H. F.; Foley, M. H.; Klebaner, A. L.; Nicol, T. H.; Page, T. M.; Theilacker, J. C.; Wands, R. H.; Wong-Squires, M. L.; Wu, G.

    2010-04-09

    Physics laboratories around the world are developing niobium superconducting radio frequency (SRF) cavities for use in particle accelerators. These SRF cavities are typically cooled to low temperatures by direct contact with a liquid helium bath, resulting in at least part of the helium container being made from pure niobium. In the U.S., the Code of Federal Regulations allows national laboratories to follow national consensus pressure vessel rules or use of alternative rules which provide a level of safety greater than or equal to that afforded by ASME Boiler and Pressure Vessel Code. Thus, while used for its superconducting properties, niobium ends up also being treated as a material for pressure vessels. This report summarizes what we have learned about the use of niobium as a pressure vessel material, with a focus on issues for compliance with pressure vessel codes. We present results of a literature search for mechanical properties and tests results, as well as a review of ASME pressure vessel code requirements and issues.

  12. Pure Niobium as a Pressure Vessel Material

    NASA Astrophysics Data System (ADS)

    Peterson, T. J.; Carter, H. F.; Foley, M. H.; Klebaner, A. L.; Nicol, T. H.; Page, T. M.; Theilacker, J. C.; Wands, R. H.; Wong-Squires, M. L.; Wu, G.

    2010-04-01

    Physics laboratories around the world are developing niobium superconducting radio frequency (SRF) cavities for use in particle accelerators. These SRF cavities are typically cooled to low temperatures by direct contact with a liquid helium bath, resulting in at least part of the helium container being made from pure niobium. In the U.S., the Code of Federal Regulations allows national laboratories to follow national consensus pressure vessel rules or use of alternative rules which provide a level of safety greater than or equal to that afforded by ASME Boiler and Pressure Vessel Code. Thus, while used for its superconducting properties, niobium ends up also being treated as a material for pressure vessels. This report summarizes what we have learned about the use of niobium as a pressure vessel material, with a focus on issues for compliance with pressure vessel codes. We present results of a literature search for mechanical properties and tests results, as well as a review of ASME pressure vessel code requirements and issues.

  13. RF Sputtering of Gold Contacts On Niobium

    NASA Technical Reports Server (NTRS)

    Barr, D. W.

    1983-01-01

    Reliable gold contacts are deposited on niobium by combination of RF sputtering and photolithography. Process results in structures having gold only where desired for electrical contact. Contacts are stable under repeated cycling from room temperature to 4.2 K and show room-temperature contact resistance as much as 40 percent below indium contacts made by thermalcompression bonding.

  14. A spiraled niobium tin superconductive ribbon

    NASA Technical Reports Server (NTRS)

    Coles, W. D.

    1973-01-01

    Copper film is vapor-deposited on clean ribbon and sprayed with photosensitive etch-resistant material. Photographic film masks are placed on ribbon and exposed to ultraviolet light. Etchant removes copper and exposure to oxidizing atmosphere forms niobium oxide. Photosensitive material is removed and ribbon is immersed in molten temperatures.

  15. Developing of superconducting niobium cavities for accelerators

    NASA Astrophysics Data System (ADS)

    Pobol, I. L.; Yurevich, S. V.

    2015-11-01

    The results of a study of structure and mechanical properties of welding joints, superconducting characteristics of the material after joining of welded components of superconducting radio frequency cavities are presented. The paper also describes the results of testing of the RF 1.3 GHz single-cell niobium cavity manufactured in the PTI NAS Belarus.

  16. Ingot Niobium RF Cavity Design and Development at BARC

    SciTech Connect

    Mittal, K. C.; Mondal, J.; Ghatak, S.; Dhavale, A. S.; Ghodke, S. R.; Vohra, R. S.; Jawale, S. B.; Dutta, D.; Pujari, P. K.; Saha, T. K.; Bapat, A. V.

    2011-03-31

    This article presents the different activity of Ingot niobium in BARC. BARC is developing a technology for the accelerator driven subcritical system (ADSS) that will be mainly utilized for the transmutation of nuclear waste and enrichment of U{sup 233}. Design and development of superconducting medium velocity cavity has been taken up as a part of the ADSS project. The design and fabrication of f = 1050 MHz, {beta} = 0.49 with Ingot niobium will be presented. Positron annihilation studies are conducted on small samples of ingot niobium to understand the defect depth profile of the niobium surface. The results are presented here.

  17. PROCESS OF COATING GRAPHITE WITH NIOBIUM-TITANIUM CARBIDE

    DOEpatents

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

    1961-07-01

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

  18. Field Emission Measurements from Niobium Electrodes

    SciTech Connect

    M. BastaniNejad, P.A. Adderley, J. Clark, S. Covert, J. Hansknecht, C. Hernandez-Garcia, R. Mammei, M. Poelker

    2011-03-01

    Increasing the operating voltage of a DC high voltage photogun serves to minimize space charge induced emittance growth and thereby preserve electron beam brightness, however, field emission from the photogun cathode electrode can pose significant problems: constant low level field emission degrades vacuum via electron stimulated desorption which in turn reduces photocathode yield through chemical poisoning and/or ion bombardment and high levels of field emission can damage the ceramic insulator. Niobium electrodes (single crystal, large grain and fine grain) were characterized using a DC high voltage field emission test stand at maximum voltage -225kV and electric field gradient > 10MV/m. Niobium electrodes appear to be superior to diamond-paste polished stainless steel electrodes.

  19. Microstructures in rapidly solidified niobium aluminides

    NASA Technical Reports Server (NTRS)

    Hebsur, Mohan G.; Locci, Ivan E.

    1988-01-01

    The microstructures of niobium aluminides produced by chill block melt spinning were compared to those of niobium aluminides produced by conventional casting. The rapidly solidified alloys were rapidly solidified by melt spinning in an argon atmosphere, and the melt-spun ribbons were examined by optical, X-ray, and TEM techniques. Microstructures were found to range from single-phase for Nb-75 at. pct Al (NbAl3) to two phase for Nb-46 at. pct Al (NbAl3 + Nb2Al). It was found that the melt spinning of Nb-aluminides produced finer grained microstructures than those produced in induction-melted ingots or in powders produced by the rotating electrode process. Ternary additions such as Cr, Ti, and Si tended to form intermetallic phases along the grain boundaries.

  20. Nitrogen doping study in ingot niobium cavities

    SciTech Connect

    Dhakal, Pashupati; Ciovati, Gianluigi; Kneisel, Peter; Myneni, Ganapati Rao; Makita, Junki

    2015-09-01

    Thermal diffusion of nitrogen in niobium superconducting radio frequency cavities at temperature ~800 °C has resulted in the increase in quality factor with a low-field Q-rise extending to Bp > 90 mT. However, the maximum accelerating gradient of these doped cavities often deteriorates below the values achieved by standard treatments prior to doping. Here, we present the results of the measurements on ingot niobium cavities doped with nitrogen at 800 °C. The rf measurements were carried out after the successive electropolishing to remove small amount of material from the inner surface layer. The result showed higher breakdown field with lower quality factor as material removal increases.

  1. Microwave mixing with niobium variable thickness bridges

    NASA Technical Reports Server (NTRS)

    Wang, L.-K.; Callegari, A.; Deaver, B. S., Jr.

    1977-01-01

    Niobium thin-film bridges 300-A thick, 1-micron wide, and 0.5-micron long joining two bulk films 5000-A thick and having normal resistance of the order of 1 ohm have been fabricated and used for microwave mixing at 10 GHz. They exhibit Josephson, bolometric, and multiple-flux-flow mixing and have useful response at 100-200 GHz. The data show in a direct way limitations imposed by flux flow and heating.

  2. Creep behavior of tungsten/niobium and tungsten/niobium-1 percent zirconium composites

    NASA Technical Reports Server (NTRS)

    Petrasek, D. W.; Titran, R. H.

    1988-01-01

    A study was conducted to determine the feasibility of using tungsten fiber reinforced niobium or niobium-1 percent zirconium matrix composites to meet the anticipated increased temperature and creep resistance requirements imposed by advanced space power systems. The results obtained on the short time tensile properties indicated that W/Nb composites showed significant improvements in high temperature strength and offer significant mass reductions for high temperature space power systems. The prime material requirement for space power systems applications is long time creep resistance. A study was conducted to determine the effect of high temperature exposure on the properties of these composites, with emphasis upon their creep behavior at elevated temperatures.

  3. Extraction spectrophotometric determination of niobium in rocks with sulfochlorophenol S

    USGS Publications Warehouse

    Childress, A.E.; Greenland, L.P.

    1980-01-01

    After acid decomposition and potassium pyrosulfate fusion, niobium (1-26 ppm) is separated from interfering elements by extraction into methyl isobutyl ketone from 6 M H2SO4-2 M HF and back-extracted into water. The niobium-sulfochloro-phenol S complex is extracted into amyl alcohol. ?? 1980.

  4. Liquid-film assisted formation of alumina/niobium interfaces

    SciTech Connect

    Sugar, Joshua D.; McKeown, Joseph T.; Marks, Robert A.; Glaeser, Andreas M.

    2002-06-16

    Alumina has been joined at 1400 degrees C using niobium-based interlayers. Two different joining approaches were compared: solid-state diffusion bonding using a niobium foil as an interlayer, and liquid-film assisted bonding using a multilayer copper/niobium/copper interlayer. In both cases, a 127-(mu)m thick niobium foil was used; =1.4-(mu)m or =3-(mu)m thick copper films flanked the niobium. Room-temperature four-point bend tests showed that the introduction of a copper film had a significant beneficial effect on the average strength and the strength distribution. Experiments using sapphire substrates indicated that during bonding the initially continuous copper film evolved into isolated copper-rich droplets/particles at the sapphire/interlayer interface, and extensive regions of direct bonding between sapphire and niobium. Film breakup appeared to initiate at either niobium grain boundary ridges, or at asperities or irregularities on the niobium surface that caused localized contact with the sapphire.

  5. STS-88 Day 01 Highlights

    NASA Technical Reports Server (NTRS)

    1998-01-01

    On this first day of the STS-88 mission, the flight crew, Commander Robert D. Cabana, Pilot Frederick W. Sturckow, and Mission Specialists Nancy J. Currie, James H. Newman, Jerry L. Ross, and Sergei Krikalev can be seen performing pre-launch activities such as eating the traditional breakfast, crew suit-up, and the ride out to the launch pad. Also, included are various panoramic views of the shuttle on the pad. The crew is readied in the "white room" for their mission. After the closing of the hatch and arm retraction, launch activities are shown including countdown, engine ignition, launch, and the separation of the Solid Rocket Boosters.

  6. STS-88 Day 06 Highlights

    NASA Technical Reports Server (NTRS)

    1998-01-01

    On this sixth day of the STS-88 mission, the flight crew, Commander Robert D. Cabana, Pilot Frederick W. Sturckow, and Mission Specialists Nancy J. Currie, James H. Newman, Jerry L. Ross, and Sergei Krikalev are awakened by Dwight Yokum's "Streets of Bakersfield," requested by the wife of Pilot Rick Sturckow, a California native. Cabana and Sturckow fire Endeavour's primary reaction control jets to raise the altitude of the International Space Station by about 5-1/2 statute miles. Later on Cabana, Sturckow and Currie are interviewed by the ABC News/Discovery Channel and MSNBC.

  7. The Manufacturing of Niobium Powder by Hunter Process

    NASA Astrophysics Data System (ADS)

    Yoon, Jae-Sik

    Niobium powder was fabricated by metallothermic reduction process using K2NbF7 as the raw material, KCl and KF as the diluents and Na as the reducing agent. The apparatus for the experiment was designed and built specifically for the present study. Varying properties of niobium powder depending on reaction temperature and excess of reducing agent were analyzed. The niobium particle size increased significantly as the reduction temperature increased from 993 to 1093 K. The particle size was fairly uniform at a given reaction temperature, varying from 0.2 μ m to 50 nm depending on the reaction temperature. The yield of niobium powder increased from 58 to 83% with an increase in reaction temperature. The average particle size of niobium powder was improved from 70 nm to 0.2 μ m with the increase in the amount of Na excess. In addition, the yield rate of Nb powder was 82% in the 5% excess sodium.

  8. Niobium oxide compositions and methods for using same

    DOEpatents

    Goodenough, John B; Han, Jian-Tao

    2014-02-11

    The disclosure relates a niobium oxide useful in anodes of secondary lithium ion batteries. Such niobium oxide has formula Li.sub.xM.sub.1-yNb.sub.yNb.sub.2O.sub.7, wherein 0.ltoreq.x.ltoreq.3, 0.ltoreq.y.ltoreq.1, and M represents Ti or Zr. The niobium oxide may be in the form of particles, which may be carbon coated. The disclosure also relates to an electrode composition containing at least one or more niobium oxides of formula Li.sub.xM.sub.1-yNb.sub.yNb.sub.2O.sub.7. The disclosure further relates to electrodes, such as anodes, and batteries containing at least one or more niobium oxides of formula Li.sub.xM.sub.1-yNb.sub.yNb.sub.2O.sub.7. Furthermore, the disclosure relates to methods of forming the above.

  9. Superconducting structure with layers of niobium nitride and aluminum nitride

    DOEpatents

    Murduck, James M.; Lepetre, Yves J.; Schuller, Ivan K.; Ketterson, John B.

    1989-01-01

    A superconducting structure is formed by depositing alternate layers of aluminum nitride and niobium nitride on a substrate. Deposition methods include dc magnetron reactive sputtering, rf magnetron reactive sputtering, thin-film diffusion, chemical vapor deposition, and ion-beam deposition. Structures have been built with layers of niobium nitride and aluminum nitride having thicknesses in a range of 20 to 350 Angstroms. Best results have been achieved with films of niobium nitride deposited to a thickness of approximately 70 Angstroms and aluminum nitride deposited to a thickness of approximately 20 Angstroms. Such films of niobium nitride separated by a single layer of aluminum nitride are useful in forming Josephson junctions. Structures of 30 or more alternating layers of niobium nitride and aluminum nitride are useful when deposited on fixed substrates or flexible strips to form bulk superconductors for carrying electric current. They are also adaptable as voltage-controlled microwave energy sources.

  10. Superconducting structure with layers of niobium nitride and aluminum nitride

    DOEpatents

    Murduck, J.M.; Lepetre, Y.J.; Schuller, I.K.; Ketterson, J.B.

    1989-07-04

    A superconducting structure is formed by depositing alternate layers of aluminum nitride and niobium nitride on a substrate. Deposition methods include dc magnetron reactive sputtering, rf magnetron reactive sputtering, thin-film diffusion, chemical vapor deposition, and ion-beam deposition. Structures have been built with layers of niobium nitride and aluminum nitride having thicknesses in a range of 20 to 350 Angstroms. Best results have been achieved with films of niobium nitride deposited to a thickness of approximately 70 Angstroms and aluminum nitride deposited to a thickness of approximately 20 Angstroms. Such films of niobium nitride separated by a single layer of aluminum nitride are useful in forming Josephson junctions. Structures of 30 or more alternating layers of niobium nitride and aluminum nitride are useful when deposited on fixed substrates or flexible strips to form bulk superconductors for carrying electric current. They are also adaptable as voltage-controlled microwave energy sources. 8 figs.

  11. Niobium matrix composites for high temperature turbine blades, phase 2

    NASA Technical Reports Server (NTRS)

    Heng, Sangvavann; Laferla, Raffaele; Tuffias, Robert H.

    1991-01-01

    This program demonstrated the feasibility of fabricating fiber-reinforced MMC (niobium matrix) turbine blades to net shape by chemical vapor infiltration (CVI). A controllable, repeatable niobium infiltration process was developed, and the kinetics of both deposition and infiltration were studied. Several continuous refractory fibers (Nicalon, Nextel 440, FP-Al2O3, HPZ, and tungsten mesh) were investigated as potential reinforcements for strengthening niobium. Thermodynamic and experimental evaluation indicated FP-Al2O3 and tungsten to be the most chemically compatible with niobium, while Nicalon, FP-Al2O3, and tungsten were found to be best with regard to reinforcing capability. Finally, a protective coating for iridium was found to provide substantial oxidation protection to the niobium blade matrix.

  12. Laser polishing of niobium for SRF applications

    SciTech Connect

    Zhao, Liang; Klopf, J. Michael; Reece, Charles E.; Kelley, Michael

    2013-09-01

    Smooth interior surfaces are desired for niobium SRF cavities, now obtained by buffered chemical polish (BCP) and/or electropolish (EP). Laser polishing is a potential alternative, having advantages of speed, freedom from chemistry and in-process inspection. Here we show that laser polishing can produce smooth topography with Power Spectral Density (PSD) measurements similar to that obtained by EP. We studied the influence of the laser power density and laser beam raster rate on the surface topography. These two factors need to be combined carefully to smooth the surface without damaging it. Computational modeling was used to simulate the surface temperature and explain the mechanism of laser polishing.

  13. Germanium-overcoated niobium Dayem bridges

    NASA Technical Reports Server (NTRS)

    Holdeman, L. B.; Peters, P. N.

    1976-01-01

    Overcoating constriction microbridges with semiconducting germanium provides additional thermal conductivity at liquid-helium temperatures to reduce the effects of self-heating in these Josephson junctions. Microwave-induced steps were observed in the I-V characteristics of an overcoated Dayem bridge fabricated in a 15-nm-thick niobium film; at least 20 steps could be counted at 4.2 K. No steps were observed in the I-V characteristics of the bridge prior to overcoating. In addition, the germanium overcoat can protect against electrical disturbances at room temperature.

  14. STS-88 Day 03 Highlights

    NASA Technical Reports Server (NTRS)

    1998-01-01

    On this third day of the STS-88 mission, the flight crew, Commander Robert D. Cabana, Pilot Frederick W. Sturckow, and Mission Specialists Nancy J. Currie, James H. Newman, Jerry L. Ross, and Sergei Krikalev check out the various tools they will use during the three scheduled spacewalks to be conducted later in the flight. They then begin an early set-up of the Shuttle's airlock in preparation for that first spacewalk. Newman and Russian cosmonaut Sergei Krikalev take part in an on-line interview by the New York Times. Currie is seen placing Unity just inches above the extended outer ring on Endeavour's docking mechanism, enabling Commander Bob Cabana to fire downward maneuvering jets to lock the shuttle's docking system to one of two Pressurized Mating Adapters (PMA's) attached to Unity.

  15. STS-88 Day 04 Highlights

    NASA Technical Reports Server (NTRS)

    1998-01-01

    On this forth day of the STS-88 mission, the flight crew, Commander Robert D. Cabana, Pilot Frederick W. Sturckow, and Mission Specialists Nancy J. Currie, James H. Newman, Jerry L. Ross, and Sergei are awakened to the sounds of "Somewhere Over the Rainbow," requested by Commander Bob Cabana's daughter, Sarah. With the three-story-high Unity connecting module latched upright in the shuttle's payload bay, Cabana takes manual control of the shuttle as it moves to within about a half-mile of Zarya. Cabana and Sturckow execute a sequence of maneuvers that will bring Endeavour directly above the module. Currie uses the robotic arm to capture the module. She then positions Zarya above Unity's docking mechanism.

  16. 40 CFR 88.302-94 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Definitions. 88.302-94 Section 88.302-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CLEAN-FUEL VEHICLES Clean-Fuel Fleet Program § 88.302-94 Definitions. The definitions in § 88.302-93 and 40 CFR part 86 also apply to this part....

  17. 19 CFR 141.88 - Computed value.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Computed value. 141.88 Section 141.88 Customs... (CONTINUED) ENTRY OF MERCHANDISE Invoices § 141.88 Computed value. When the port director determines that information as to computed value is necessary in the appraisement of any class or kind of merchandise,...

  18. 19 CFR 141.88 - Computed value.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 2 2011-04-01 2011-04-01 false Computed value. 141.88 Section 141.88 Customs... (CONTINUED) ENTRY OF MERCHANDISE Invoices § 141.88 Computed value. When the port director determines that information as to computed value is necessary in the appraisement of any class or kind of merchandise,...

  19. 19 CFR 141.88 - Computed value.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 2 2014-04-01 2014-04-01 false Computed value. 141.88 Section 141.88 Customs... (CONTINUED) ENTRY OF MERCHANDISE Invoices § 141.88 Computed value. When the port director determines that information as to computed value is necessary in the appraisement of any class or kind of merchandise,...

  20. 19 CFR 141.88 - Computed value.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 2 2012-04-01 2012-04-01 false Computed value. 141.88 Section 141.88 Customs... (CONTINUED) ENTRY OF MERCHANDISE Invoices § 141.88 Computed value. When the port director determines that information as to computed value is necessary in the appraisement of any class or kind of merchandise,...

  1. 19 CFR 141.88 - Computed value.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 2 2013-04-01 2013-04-01 false Computed value. 141.88 Section 141.88 Customs... (CONTINUED) ENTRY OF MERCHANDISE Invoices § 141.88 Computed value. When the port director determines that information as to computed value is necessary in the appraisement of any class or kind of merchandise,...

  2. 7 CFR 3570.88 - Management assistance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Management assistance. 3570.88 Section 3570.88 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, DEPARTMENT OF AGRICULTURE COMMUNITY PROGRAMS Community Facilities Grant Program § 3570.88 Management assistance....

  3. 7 CFR 3570.88 - Management assistance.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Management assistance. 3570.88 Section 3570.88 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, DEPARTMENT OF AGRICULTURE COMMUNITY PROGRAMS Community Facilities Grant Program § 3570.88 Management assistance....

  4. 7 CFR 3570.88 - Management assistance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Management assistance. 3570.88 Section 3570.88 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, DEPARTMENT OF AGRICULTURE COMMUNITY PROGRAMS Community Facilities Grant Program § 3570.88 Management assistance....

  5. 40 CFR 98.88 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Definitions. 98.88 Section 98.88 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Cement Production § 98.88 Definitions. All terms used in this subpart have the...

  6. 40 CFR 98.88 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Definitions. 98.88 Section 98.88 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Cement Production § 98.88 Definitions. All terms used in this subpart have the...

  7. 37 CFR 1.88 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false 1.88 Section 1.88 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE GENERAL RULES OF PRACTICE IN PATENT CASES National Processing Provisions The Drawings § 1.88 Models, Exhibits,...

  8. 37 CFR 1.88 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2013-07-01 2013-07-01 false 1.88 Section 1.88 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE GENERAL RULES OF PRACTICE IN PATENT CASES National Processing Provisions The Drawings § 1.88 Models, Exhibits,...

  9. 40 CFR 88.202-94 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Definitions. 88.202-94 Section 88.202-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CLEAN-FUEL VEHICLES California Pilot Test Program § 88.202-94 Definitions. (a) The definitions...

  10. 40 CFR 88.309 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false 88.309 Section 88.309 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CLEAN-FUEL VEHICLES Clean-Fuel Fleet Program § 88.309...

  11. 32 CFR 88.5 - Responsibilities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 1 2011-07-01 2011-07-01 false Responsibilities. 88.5 Section 88.5 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE PERSONNEL, MILITARY AND CIVILIAN TRANSITION ASSISTANCE FOR MILITARY PERSONNEL § 88.5 Responsibilities. (a) The Assistant Secretary of...

  12. 32 CFR 88.5 - Responsibilities.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 1 2013-07-01 2013-07-01 false Responsibilities. 88.5 Section 88.5 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE PERSONNEL, MILITARY AND CIVILIAN TRANSITION ASSISTANCE FOR MILITARY PERSONNEL § 88.5 Responsibilities. (a) The Assistant Secretary of...

  13. 9 CFR 381.88 - Parasites.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Parasites. 381.88 Section 381.88 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... § 381.88 Parasites. Organs or other parts of carcasses which are found to be infested with parasites,...

  14. 7 CFR 1780.88 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 12 2014-01-01 2013-01-01 true 1780.88 Section 1780.88 Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE (CONTINUED) WATER... Documents for Public Body Applicants § 1780.88...

  15. 9 CFR 381.88 - Parasites.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Parasites. 381.88 Section 381.88 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... § 381.88 Parasites. Organs or other parts of carcasses which are found to be infested with parasites,...

  16. 9 CFR 381.88 - Parasites.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Parasites. 381.88 Section 381.88 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... § 381.88 Parasites. Organs or other parts of carcasses which are found to be infested with parasites,...

  17. 9 CFR 381.88 - Parasites.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Parasites. 381.88 Section 381.88 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... § 381.88 Parasites. Organs or other parts of carcasses which are found to be infested with parasites,...

  18. 9 CFR 381.88 - Parasites.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Parasites. 381.88 Section 381.88 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... § 381.88 Parasites. Organs or other parts of carcasses which are found to be infested with parasites,...

  19. 42 CFR 430.88 - Evidence.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Evidence. 430.88 Section 430.88 Public Health... Plans and Practice to Federal Requirements § 430.88 Evidence. (a) Evidentiary purpose. The hearing is directed to receiving factual evidence and expert opinion testimony related to the issues involved in...

  20. 7 CFR 3570.88 - Management assistance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Management assistance. 3570.88 Section 3570.88 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, DEPARTMENT OF AGRICULTURE COMMUNITY PROGRAMS Community Facilities Grant Program § 3570.88 Management assistance....

  1. 21 CFR 500.88 - Regulatory method.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Regulatory method. 500.88 Section 500.88 Food and... § 500.88 Regulatory method. (a) The sponsor shall submit for evaluation and validation a regulatory method developed to monitor compliance with FDA's operational definition of no residue. (b)...

  2. 42 CFR 88.2 - General provisions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... AND RELATED ACTIVITIES WORLD TRADE CENTER HEALTH PROGRAM § 88.2 General provisions. (a) Designated... 42 Public Health 1 2011-10-01 2011-10-01 false General provisions. 88.2 Section 88.2 Public Health... appointment must be in writing. (2) There may be only one representative at any time. After one...

  3. 37 CFR 1.88 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false 1.88 Section 1.88 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE GENERAL RULES OF PRACTICE IN PATENT CASES National Processing Provisions The Drawings § 1.88 Models, Exhibits,...

  4. 40 CFR 98.88 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Definitions. 98.88 Section 98.88 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Cement Production § 98.88 Definitions. All terms used in this subpart have the...

  5. 40 CFR 98.88 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Definitions. 98.88 Section 98.88 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Cement Production § 98.88 Definitions. All terms used in this subpart have the...

  6. 34 CFR 668.88 - Hearing.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 3 2011-07-01 2011-07-01 false Hearing. 668.88 Section 668.88 Education Regulations of... Proceedings § 668.88 Hearing. (a) A hearing is an orderly presentation of arguments and evidence conducted by a hearing official. (b) If the hearing official, the designated department official who brought...

  7. 34 CFR 668.88 - Hearing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false Hearing. 668.88 Section 668.88 Education Regulations of... Proceedings § 668.88 Hearing. (a) A hearing is an orderly presentation of arguments and evidence conducted by a hearing official. (b) If the hearing official, the designated department official who brought...

  8. 50 CFR 260.88 - Political activity.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 11 2012-10-01 2012-10-01 false Political activity. 260.88 Section 260.88... Products for Human Consumption Miscellaneous § 260.88 Political activity. All inspectors and licensed... part in political management or in political campaigns. Political activities in city, county, State,...

  9. 50 CFR 260.88 - Political activity.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Political activity. 260.88 Section 260.88... Products for Human Consumption Miscellaneous § 260.88 Political activity. All inspectors and licensed... part in political management or in political campaigns. Political activities in city, county, State,...

  10. 50 CFR 260.88 - Political activity.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 11 2014-10-01 2014-10-01 false Political activity. 260.88 Section 260.88... Products for Human Consumption Miscellaneous § 260.88 Political activity. All inspectors and licensed... part in political management or in political campaigns. Political activities in city, county, State,...

  11. 50 CFR 260.88 - Political activity.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 11 2013-10-01 2013-10-01 false Political activity. 260.88 Section 260.88... Products for Human Consumption Miscellaneous § 260.88 Political activity. All inspectors and licensed... part in political management or in political campaigns. Political activities in city, county, State,...

  12. 50 CFR 260.88 - Political activity.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Political activity. 260.88 Section 260.88... Products for Human Consumption Miscellaneous § 260.88 Political activity. All inspectors and licensed... part in political management or in political campaigns. Political activities in city, county, State,...

  13. 21 CFR 808.88 - Pennsylvania.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pennsylvania. 808.88 Section 808.88 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EXEMPTIONS FROM FEDERAL PREEMPTION OF STATE AND LOCAL MEDICAL DEVICE REQUIREMENTS Listing of Specific State and Local Exemptions § 808.88...

  14. 32 CFR 88.4 - Policy.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false Policy. 88.4 Section 88.4 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE PERSONNEL, MILITARY AND CIVILIAN TRANSITION ASSISTANCE FOR MILITARY PERSONNEL § 88.4 Policy. It is DoD policy that: (a) Transition assistance...

  15. 40 CFR 88.102-94 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Definitions. 88.102-94 Section 88.102-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CLEAN-FUEL VEHICLES Emission Standards for Clean-Fuel Vehicles § 88.102-94 Definitions. Any terms defined in 40 CFR part 86 and not defined in this...

  16. 40 CFR 88.102-94 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Definitions. 88.102-94 Section 88.102-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CLEAN-FUEL VEHICLES Emission Standards for Clean-Fuel Vehicles § 88.102-94 Definitions. Any terms defined in 40 CFR part 86 and not defined in this...

  17. 32 CFR 88.6 - Information requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false Information requirements. 88.6 Section 88.6 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE PERSONNEL, MILITARY AND CIVILIAN TRANSITION ASSISTANCE FOR MILITARY PERSONNEL § 88.6 Information requirements. The quarterly...

  18. 32 CFR 88.6 - Information requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 1 2013-07-01 2013-07-01 false Information requirements. 88.6 Section 88.6 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE PERSONNEL, MILITARY AND CIVILIAN TRANSITION ASSISTANCE FOR MILITARY PERSONNEL § 88.6 Information requirements. The quarterly...

  19. 9 CFR 88.2 - General information.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false General information. 88.2 Section 88.2... EQUINES FOR SLAUGHTER § 88.2 General information. (a) State governments may enact and enforce regulations... transported the equines information regarding the business of that individual or other entity. When...

  20. 7 CFR 3570.88 - Management assistance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Management assistance. 3570.88 Section 3570.88 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, DEPARTMENT OF AGRICULTURE COMMUNITY PROGRAMS Community Facilities Grant Program § 3570.88 Management assistance....

  1. 21 CFR 500.88 - Regulatory method.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Regulatory method. 500.88 Section 500.88 Food and... § 500.88 Regulatory method. (a) The sponsor shall submit for evaluation and validation a regulatory method developed to monitor compliance with FDA's operational definition of no residue. (b)...

  2. 38 CFR 4.88 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false 4.88 Section 4.88 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS SCHEDULE FOR RATING DISABILITIES Disability Ratings Infectious Diseases, Immune Disorders and Nutritional Deficiencies § 4.88...

  3. 38 CFR 4.88 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false 4.88 Section 4.88 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS SCHEDULE FOR RATING DISABILITIES Disability Ratings Infectious Diseases, Immune Disorders and Nutritional Deficiencies § 4.88...

  4. 38 CFR 4.88 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false 4.88 Section 4.88 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS SCHEDULE FOR RATING DISABILITIES Disability Ratings Infectious Diseases, Immune Disorders and Nutritional Deficiencies § 4.88...

  5. 38 CFR 4.88 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false 4.88 Section 4.88 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS SCHEDULE FOR RATING DISABILITIES Disability Ratings Infectious Diseases, Immune Disorders and Nutritional Deficiencies § 4.88...

  6. 21 CFR 500.88 - Regulatory method.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Regulatory method. 500.88 Section 500.88 Food and... § 500.88 Regulatory method. (a) The sponsor shall submit for evaluation and validation a regulatory method developed to monitor compliance with FDA's operational definition of no residue. (b)...

  7. 21 CFR 500.88 - Regulatory method.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Regulatory method. 500.88 Section 500.88 Food and... § 500.88 Regulatory method. (a) The sponsor shall submit for evaluation and validation a regulatory method developed to monitor compliance with FDA's operational definition of no residue. (b)...

  8. 45 CFR 96.88 - Administrative costs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 1 2014-10-01 2014-10-01 false Administrative costs. 96.88 Section 96.88 Public... Assistance Program § 96.88 Administrative costs. (a) Costs of planning and administration. Any expenditure... be included in determining administrative costs subject to the statutory limitation on...

  9. 32 CFR 88.5 - Responsibilities.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 1 2012-07-01 2012-07-01 false Responsibilities. 88.5 Section 88.5 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE PERSONNEL, MILITARY AND CIVILIAN TRANSITION ASSISTANCE FOR MILITARY PERSONNEL § 88.5 Responsibilities. (a) The Assistant Secretary of...

  10. 32 CFR 88.5 - Responsibilities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false Responsibilities. 88.5 Section 88.5 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE PERSONNEL, MILITARY AND CIVILIAN TRANSITION ASSISTANCE FOR MILITARY PERSONNEL § 88.5 Responsibilities. (a) The Assistant Secretary of...

  11. 49 CFR 393.88 - Television receivers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Television receivers. 393.88 Section 393.88... NECESSARY FOR SAFE OPERATION Miscellaneous Parts and Accessories § 393.88 Television receivers. Any motor vehicle equipped with a television viewer, screen or other means of visually receiving a...

  12. 24 CFR 200.88 - Late charge.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Late charge. 200.88 Section 200.88... Requirements for Existing Projects Mortgage Provisions § 200.88 Late charge. The mortgage may provide for the collection by the mortgagee of a late charge in accordance with terms, conditions and standards of...

  13. 24 CFR 200.88 - Late charge.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Late charge. 200.88 Section 200.88... Requirements for Existing Projects Mortgage Provisions § 200.88 Late charge. The mortgage may provide for the collection by the mortgagee of a late charge in accordance with terms, conditions and standards of...

  14. 40 CFR 763.88 - Assessment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Assessment. 763.88 Section 763.88 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT ASBESTOS Asbestos-Containing Materials in Schools § 763.88 Assessment. (a)(1) For each inspection and...

  15. 40 CFR 763.88 - Assessment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Assessment. 763.88 Section 763.88 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT ASBESTOS Asbestos-Containing Materials in Schools § 763.88 Assessment. (a)(1) For each inspection and...

  16. 40 CFR 763.88 - Assessment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Assessment. 763.88 Section 763.88 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT ASBESTOS Asbestos-Containing Materials in Schools § 763.88 Assessment. (a)(1) For each inspection and...

  17. 40 CFR 763.88 - Assessment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Assessment. 763.88 Section 763.88 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT ASBESTOS Asbestos-Containing Materials in Schools § 763.88 Assessment. (a)(1) For each inspection and...

  18. 40 CFR 763.88 - Assessment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Assessment. 763.88 Section 763.88 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT ASBESTOS Asbestos-Containing Materials in Schools § 763.88 Assessment. (a)(1) For each inspection and...

  19. 32 CFR 88.4 - Policy.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 1 2013-07-01 2013-07-01 false Policy. 88.4 Section 88.4 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE PERSONNEL, MILITARY AND CIVILIAN TRANSITION ASSISTANCE FOR MILITARY PERSONNEL § 88.4 Policy. It is DoD policy that: (a) Transition assistance programs prepare separating Service members and...

  20. WSR-88D Cell Trends

    NASA Technical Reports Server (NTRS)

    Wheeler, Mark M.

    1998-01-01

    This report documents the Applied Meteorology Unit's evaluation of the Cell Trends display as a tool for radar operators to use in their evaluation of storm cell strength. The objective of the evaluation is to assess the utility of the WSR-88D graphical Cell Trends display for local radar cell interpretation in support of the 45th Weather Squadron (45 WS), Spaceflight Meteorology Group (SMG), and National Weather Service (NWS) Melbourne (MLB) operational requirements. The analysis procedure was to identify each cell and track the maximum reflectivity, height of maximum reflectivity, storm top, storm base, hail and severe hail probability, cell-based Vertically Integrated Liquid (VIL) and core aspect ratio using WATADS Build 9.0 cell trends information. One problem noted in the analysis phase was that the Storm Cell Identification and Tracking (SCIT) algorithm had a difficult time tracking the small cells associated with the Florida weather regimes. The analysis indicated numerous occasions when a cell track would end or an existing cell would be give a new ID in the middle of its life cycle. This investigation has found that most cells, which produce hail or microburst events, have discernable Cell Trends signatures. Forecasters should monitor the PUP's Cell Trends display for cells that show rapid (1 scan) changes in both the heights of maximum reflectivity and cell-based VIEL. It is important to note that this a very limited data set (four case days). Fifty-two storm cells were analyzed during those four days. The above mentioned t=ds, increase in the two cell attributes for hail events and decrease in the two cell attributes for wind events were noted in most of the cells. The probability of detection was 88% for both events. The False Alarm Rate (FAR) was a 36% for hail events and a respectable 25% for microburst events. In addition the Heidke Skill Score (HSS) is 0.65 for hail events and 0.67 for microburst events. For random forecast the HSS is 0 and that a

  1. Niobium alloy heat pipes for use in oxidizing environments

    NASA Astrophysics Data System (ADS)

    Craig Wojcik, C.

    1991-01-01

    Niobium alloys have been used for many years in rocket propulsion systems and afterburner sections of gas turbine engines. In these applications, adequate oxidation resistance is provided by protective silicide coatings. By utilizing these coatings and niobium powder metallurgy to produce porous wicks, it has been demonstrated that niobium alloy heat pipes can comfortably operate in flame temperatures exceeding 3000 K. Results of lithium corrosion tests on C-103 (Nb-10%Hf-1%Ti) up to 1477 K will be presented along with thermal performance data for specific heat pipe designs.

  2. SEPARATION OF URANIUM FROM ZIRCONIUM AND NIOBIUM BY SOLVENT EXTRACTION

    DOEpatents

    Voiland, E.E.

    1958-05-01

    A process for separation of the uranium from zirconium and/or niobium values contained in 3 to 7M aqueous nitric acid solutions is described. This is accomplished by adding phosphoric acid anions to the nitric acid solution containing the uranium, zirconium, and/or niobium in an amount sufficient to make the solution 0.05 to 0.2M in phosphate ion and contacting the solution with an organic water-immiscible solvent such as MEK, whereby the uranyl values are taken up by the extract phase while the zirconium and niobium preferentially remain in the aqueous raffinate.

  3. Research & Development on Superconducting Niobium Materials via Magnetic Measurements

    SciTech Connect

    S. B. Roy, V. C. Sahni, and G. R. Myneni

    2011-03-01

    We present a study of superconducting properties of both large grain (1 mm average grain size) and small grain (50 micron average grain size) Niobium materials containing varying amounts of Tantalum impurities that have been used in the fabrication of high accelerating gradient superconducting radio frequency cavities. We found that a buffered chemical polishing of these Niobium samples causes a distinct reduction in the superconducting parameters like TC, wt- ppm to 1300 wt-ppm. Implications of these results on the performance of niobium superconducting radio frequency cavities are discussed, especially the anomalous high field RF losses that have been reported in the literature.

  4. STS-88 Post Flight Presentation

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The flight crew of the STS-88 mission, Commander Robert D. Cabana, Pilot Frederick W. Sturckow, and Mission Specialists Nancy J. Currie, Jerry L. Ross, James H. Newman, and Sergei K. Krikalev, present a video mission over-view of their space flight. Images include prelaunch activities such as eating the traditional breakfast, crew suit-up, and the ride out to the launch pad. Also, included are various panoramic views of the shuttle on the pad. The crew can be seen being readied in the "white room" for their mission. After the closing of the hatch and arm retraction, launch activities are shown including countdown, engine ignition, launch, and the separation of the Solid Rocket Boosters. Once the seven-day mission begins, the astronauts comment on the mating of the U.S.-built Node 1 station element to the Functional Energy Block (FGB) which was already in orbit, and two EVAs that were planned to connect power and data transmission cables between the Node and the FGB. The crew can also be seen conducting a series of rendezvous maneuvers similar to those conducted on other Shuttle missions to reach the orbiting FGB.

  5. STS-88 Day 10 Highlights

    NASA Technical Reports Server (NTRS)

    1998-01-01

    On this tenth day of the STS-88 mission, the flight crew, Commander Robert D. Cabana, Pilot Frederick W. Sturckow, and Mission Specialists Nancy J. Currie, James H. Newman, Jerry L. Ross, and Sergei Krikalev are awakened by the sounds of Elvis Presley's "Hound Dog". Today's activities are devoted mostly to tasks that ready the station for future assembly work. The crew's first job is to release some cable ties on four cables connected on an earlier space walk, three located on Unity's upper mating adapter and one on its lower adapter, to relieve tension on the lines. The space walkers also will check an insulation cover on one cable connection on the lower Pressurized Mating Adapter (PMA 2) to make sure it is fully installed. Near the end of the space walk, the astronauts conduct a detailed photographic survey of the space station from top to bottom. Finally, each astronaut test fires the Simplified Aid for Extravehicular Activity Rescue (SAFER) jet backpacks they are wearing, a type of space "lifejacket," that would allow an astronaut to fly back to the station if they should ever become untethered.

  6. STS-88 Day 11 Highlights

    NASA Technical Reports Server (NTRS)

    1998-01-01

    On this eleventh day of the STS-88 mission, the flight crew, Commander Robert D. Cabana, Pilot Frederick W. Sturckow, and Mission Specialists Nancy J. Currie, James H. Newman, Jerry L. Ross, and Sergei Krikalev are awakened with the song "Goodnight, Sweetheart, Goodnight". Pilot Rick Sturckow undocks Endeavour from the station and backs the shuttle away to a distance of 450 feet above the station before beginning a nose-forward fly-around. Later Cabana, Sturckow and Ross deploy the SAC-A satellite from Endeavour's payload bay. SAC-A is a small, self-contained, non-recoverable satellite built by the Argentinean National Commission of Space Activities. The cube-shaped, 590-pound satellite will test and characterize the performance of new equipment and technologies that may be used in future scientific or operational missions. The payload includes a differential global positioning system, a magnetometer, silicon solar cells, a charge-coupled device Earth camera and a whale tracker experiment.

  7. Creep behavior of tungsten/niobium and tungsten/niobium-1 percent zirconium composites

    NASA Technical Reports Server (NTRS)

    Petrasek, Donald W.; Titran, Robert H.

    1988-01-01

    The creep behavior and microstructural stability of tungsten fiber reinforced niobium and niobium 1 percent zirconium was determined at 1400 and 1500 K in order to assess the potential of this material for use in advanced space power systems. The creep behavior of the composite materials could be described by a power law creep equation. A linear relationship was found to exist between the minimum creep rate of the composite and the inverse of the composite creep rupture life. The composite materials had an order of magnitude increase in stress to achieve 1 percent creep strain and in rupture strength at test temperatures of 1400 and 1500 K compared to unreinforced material. The composite materials were also stronger than the unreinforced materials by an order of magnitude when density was taken into consideration. Results obtained on the creep behavior and microstructural stability of the composites show significant potential improvement in high temperature properties and mass reduction for space power system components.

  8. Crystallography and Morphology of Niobium Carbide in As-Cast HP-Niobium Reformer Tubes

    NASA Astrophysics Data System (ADS)

    Buchanan, Karl G.; Kral, Milo V.

    2012-06-01

    The microstructures of two as-cast heats of niobium-modified HP stainless steels were characterized. Particular attention was paid to the interdendritic niobium-rich carbides formed during solidification of these alloys. At low magnifications, these precipitates are grouped in colonies of similar lamellae. Higher magnifications revealed that the lamellae actually obtain two distinct morphologies. The type I morphology exhibits broad planar interfaces with a smooth platelike shape. Type II lamellae have undulating interfaces and an overall reticulated shape. To provide further insight into the origin of these two different morphologies, the microstructure and crystallography of each have been studied in detail using high resolution scanning electron microscopy, transmission electron microscopy, various electron diffraction methods (electron backscatter diffraction (EBSD), selected area diffraction (SAD), and convergent beam electron diffraction (CBED)), and energy dispersive X-ray spectroscopy.

  9. Synthesis of piezoelectric and bioactive NaNbO3 from metallic niobium and niobium oxide.

    PubMed

    Prado da Silva, Marcelo Henrique; da Rocha, Daniel Navarro; de Andrade Gobbo, Luciano; Dos Santos Azevedo, Luciana Maria; Louro, Luís Henrique Leme; Machado Costa, Andréa; Brant de Campos, José

    2016-07-01

    NaNbO3 was synthesized by two different routes, one using metallic niobium powder, and another using niobium oxide (Nb2 O5 ) powder. In both routes an aqueous sodium hydroxide solution was used to hydrothermally treating the powders. In the first approach, the solution concentrations were 3M, 1M, and 0.5M. The second route used solution concentrations of 10M and 12.5M. After the hydrothermal treatments, the powders were heat treated in order to synthesize NaNbO3 . The products were characterized by scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS), and X-ray diffraction (XRD) with Rietveld refinement. The phases were identified by means of X-ray diffraction (XRD) with Rietveld refinement. It was observed that the molar concentrations of the solutions had opposing effects for each route. An antiferroelectric phase was found in both routes. In the niobium metallic route, a ferroelectric phase was also synthesized. This study proves that piezoelectric NaNbO3 can be obtained after alkali treatment of both Nb and Nb2 O5. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 979-985, 2016. PMID:25980635

  10. Electroplating and stripping copper on molybdenum and niobium

    NASA Technical Reports Server (NTRS)

    Power, J. L.

    1978-01-01

    Molybdenum and niobium are often electroplated and subsequently stripped of copper. Since general standard plating techniques produce poor quality coatings, general procedures have been optimized and specified to give good results.

  11. Manufacture of superconducting niobium cavity parts by hydropercussion punching

    NASA Astrophysics Data System (ADS)

    Azaryan, N. S.; Shirkov, G. D.; Zhurauski, A. Yu.; Petrakovski, V. S.; Batouritski, M. A.

    2016-03-01

    A complete cycle of manufacturing all parts of superconducting niobium cavities which comprise two half-cells, two drift tubes, and two flanges each has been developed. The cavity half-cells are manufactured by hydropercussion punching, which has a number of advantages over the instrumental stamping technique. For the first time, the diagram of formability of ultrapure niobium has been experimentally obtained for hydropercussion punching and the key parameters of the process have been determined that ensure complete deep-drawing of workpieces, viz., the value of the limit drawing ratio of ultrapure niobium that is 1.92 at a specific impact energy of 0.42 MJ/m2. The deviations of the half-cell dimensions from the rated values do not exceed 0.1 mm. Production tools required for all manufacturing steps have been created. The parameters of machining of the niobium cavity parts prior to welding have been experimentally established.

  12. Studies of Niobium Thin Film Produced by Energetic Vacuum Deposition

    SciTech Connect

    Genfa Wu; Anne-Marie Valente; H. Phillips; Haipeng Wang; Andy Wu; T. J. Renk; P Provencio

    2004-05-01

    An energetic vacuum deposition system has been used to study deposition energy effects on the properties of niobium thin films on copper and sapphire substrates. The absence of working gas avoids the gaseous inclusions commonly seen with sputtering deposition. A biased substrate holder controls the deposition energy. Transition temperature and residual resistivity ratio of the niobium thin films at several deposition energies are obtained together with surface morphology and crystal orientation measurements by AFM inspection, XRD and TEM analysis. The results show that niobium thin films on sapphire substrate exhibit the best cryogenic properties at deposition energy around 123 eV. The TEM analysis revealed that epitaxial growth of film was evident when deposition energy reaches 163 eV for sapphire substrate. Similarly, niobium thin film on copper substrate shows that film grows more oriented with higher deposition energy and grain size reaches the scale of the film thickness at the deposition energy around 153 eV.

  13. Electrochemical Synthesis of Niobium-Hafnium Coatings in Molten Salts

    NASA Astrophysics Data System (ADS)

    Kuznetsov, Sergey A.; Kuznetsova, Svetlana V.

    2007-08-01

    Graphite is widely used in technology because of its unique properties. A drawback of graphite is its low heat resistance in oxidizing atmospheres. To increase its heat resistance, Nb-Hf protective coatings were synthesized. Electrodeposition of niobium coatings on graphite with subsequent precise surface alloying of niobium with hafnium was studied. Electrochemical synthesis of Nb-Hf coatings from molten salt systems containing compounds of niobium and hafnium was used too. It was shown that Nb-Hf coatings with a planar growing front can be obtained if the concentration and therefore the limiting current density of the more electropositive component Nb is kept low. Nb-Hf coatings with a thickness of 20 - 30 μm have been obtained in this way from an NaCl-KCl-K2NbF7 (1 wt%)-K2HfF6 (10 wt%)-NaF (5 wt%) melt, above the limiting current density of niobium deposition.

  14. Effects of Impurities on Alumina-Niobium InterfacialMicrostructures

    SciTech Connect

    McKeown, Joseph T.; Sugar, Joshua D.; Gronsky, Ronald; Glaeser,Andreas M.

    2005-06-20

    Optical microscopy, scanning electron microscopy, and transmission electron microscopy were employed to examine the interfacial microstructural effects of impurities in alumina substrates used to fabricate alumina-niobium interfaces via liquid-film-assisted joining. Three types of alumina were used: undoped high-purity single-crystal sapphire; a high-purity, high-strength polycrystalline alumina; and a lower-purity, lower-strength polycrystalline alumina. Interfaces formed between niobium and both the sapphire and high-purity polycrystalline alumina were free of detectable levels of impurities. In the lower-purity alumina, niobium silicides were observed at the alumina-niobium interface and on alumina grain boundaries near the interface. These silicides formed in small-grained regions of the alumina and were found to grow from the interface into the alumina along grain boundaries. Smaller silicide precipitates found on grain boundaries are believed to form upon cooling from the bonding temperature.

  15. Niobium Silicon Alloys for Kinetic Inductance Detectors

    NASA Astrophysics Data System (ADS)

    Calvo, M.; D'Addabbo, A.; Monfardini, A.; Benoit, A.; Boudou, N.; Bourrion, O.; Catalano, A.; Dumoulin, L.; Goupy, J.; Le Sueur, H.; Marnieros, S.

    2014-08-01

    We are studying the properties of Niobium Silicon amorphous alloys as a candidate material for the fabrication of highly sensitive kinetic inductance detectors (KID), optimized for very low optical loads. As in the case of other composite materials, the NbSi properties can be changed by varying the relative amounts of its components. Using a NbSi film with T = 1 K we have been able to obtain the first NbSi resonators, observe an optical response and acquire a spectrum in the band 50-300 GHz. The data taken show that this material has very high kinetic inductance and normal state surface resistivity . These properties are ideal for the development of KID. More measurements are planned to further characterize the NbSi alloy and fully investigate its potential.

  16. Vacuum plasma spraying of tantalum and niobium

    SciTech Connect

    Lugscheider, E.; Eschnauer, H.; Haeuser, B.; Jaeger, D.

    1985-11-01

    Vacuum plasma spraying is a suitable process for producing high quality coatings of reactive metals such as tantalum and niobium. Ta and Nb coatings used for corrosion protection must be extremely dense, homogeneous, and of high purity and adhesion. Hence, the process parameters have to be carefully optimized even with regard to the spraying powder, its grain size and morphology. Spraying equipment with vacuum systems which allow for a final pressure of 10/sup -3/ mbar, which have heated and evacuated powder feeder units, and heated substrates, as well as the use of powders with high purity and low gas content, are required for producing high quality Ta and Nb coatings. Corrosion tests in sulfuric acid and aqua regia at different concentrations show that Ta and Nb coatings sprayed under optimized conditions have high resistance to both general and localized corrosion.

  17. A bulk niobium superconducting quarter wave resonator

    SciTech Connect

    Ben-Zvi, I. ); Chiaveri, E. ); Elkonin, B.V. ); Facco, A.; Sokolowski, J.S. . Lab. Nazionale di Legnaro)

    1990-01-01

    A bath-cooled all-niobium 160 MHz quarter wave resonator prototype was constructed and tested. The objective of this research has been the development of a high performance accelerating element with {beta}{sub opt} {approx equal} 0.11 for the ALPI linac at the Laboratori Nazionali di Legnaro. The design of this resonator was based upon a previous 150 MHz model, with minor changes due to the different frequency and to modified welding procedure. An accelerating field of 5 MV/m was achieved at a power dissipation of 10 W and the low power Q was 2.4 {times} 10{sup 8}. The resonator could dissipate 70 W of power without thermal breakdown. 16 refs., 2 figs., 1 tab.

  18. Enhanced characterization of niobium surface topography

    NASA Astrophysics Data System (ADS)

    Xu, Chen; Tian, Hui; Reece, Charles E.; Kelley, Michael J.

    2011-12-01

    Surface topography characterization is a continuing issue for the superconducting radio frequency (SRF) particle accelerator community. Efforts are under way to both improve surface topography and its characterization and analysis using various techniques. In measurement of topography, power spectral density (PSD) is a promising method to quantify typical surface parameters and develop scale-specific interpretations. PSD can also be used to indicate how the process modifies topography at different scales. However, generating an accurate and meaningful topographic PSD of an SRF surface requires careful analysis and optimization. In this report, niobium surfaces with different process histories are sampled with atomic force microscopy and stylus profilometry and analyzed to trace topography evolution at different scales. An optimized PSD analysis protocol to serve SRF needs is presented.

  19. International strategic minerals inventory summary report; niobium (columbium) and tantalum

    USGS Publications Warehouse

    Crockett, R.N.; Sutphin, D.M.

    1993-01-01

    Major world resources of niobium and tantalum are described in this summary report of information in the International Strategic Minerals Inventory (ISMI). ISMI is a cooperative data-collection effort of earth-science and mineral-resource agencies in Australia, Canada, the Federal Republic of Germany, the Republic of South Africa, the United Kingdom, and the United States of America. Part I of this report presents an overview of the resources and potential supply of niobium and tantalum based on inventory information; Part II contains tables of both geologic and mineral-resource information and includes production data collected by ISMI participants. Niobium is used principally as an alloying element in special steels and superalloys, and tantalum is used mainly in electronics. Minerals in the columbite-tantalite series are principal ore minerals of niobium and tantalum. Pyrochlore is a principal source of niobium. These minerals are found in carbonatite, certain rocks in alkaline igneous complexes, pegmatite, and placer deposits. ISMI estimates show that there are over 7 million metric tons of niobium and almost 0.5 million metric tons of tantalum in known deposits, outside of China and the former Soviet Union, for which reliable estimates have been made. Brazilian deposits, followed by Canadian deposits, contain by far the largest source of niobium. Tantalum production is spread widely among several countries, and Brazil and Canada are the most significant of these producers. Brazil's position is further strengthened by potential byproduct columbite from tin mining. Present economically exploitable resources of niobium appear to be sufficient for the near future, but Brazil will continue to be the predominant world supplier of ferrocolumbium. Tantalum, a byproduct of tin production, has been captive to the fluctuations of that market, but resources in pegmatite in Canada and Australia make it likely that future increases in the present modest demand will be met.

  20. Parameter Optimization for Laser Polishing of Niobium for SRF Applications

    SciTech Connect

    Zhao, Liang; Klopf, John Michael; Reece, Charles E.; Kelley, Michael J.

    2013-06-01

    Surface smoothness is critical to the performance of SRF cavities. As laser technology has been widely applied to metal machining and surface treatment, we are encouraged to use it on niobium as an alternative to the traditional wet polishing process where aggressive chemicals are involved. In this study, we describe progress toward smoothing by optimizing laser parameters on BCP treated niobium surfaces. Results shows that microsmoothing of the surface without ablation is achievable.

  1. Characterization of electron beam melted uranium - 6% niobium ingots

    SciTech Connect

    McKoon, R.H.

    1997-10-31

    A study was undertaken at Lawrence Livermore National Laboratory to characterize uranium, 6{percent} niobium ingots produced via electron beam melting,hearth refining and continuous casting and to compare this material with conventional VIM/skull melt /VAR material. Samples of both the ingot and feed material were analyzed for niobium, trace metallic elements, carbon, oxygen and nitrogen. Ingot samples were also inspected metallographically and via microprobe analysis.

  2. Niobium (columbium) and tantalum resources of Brazil

    USGS Publications Warehouse

    White, Max Gregg

    1975-01-01

    Most of the niobium resources of Brazil occur as pyrochlore in carbonatites within syenitic intrusives of Late Cretaceous to early Tertiary age in western Minas Gerais and southeastern Goils. Minor amounts of it are produced together with tantalum from columbite-tantalite concentrates from pegmatites and placers adjacent to them, in the Sao Joao del Rei district in south-central Minas Gerais. All the niobium and tantalum produced in Brazil is exported. The only pyrochlore mined is from the Barreiro carbonatite deposit near Araxa in Minas Gerais where concentrates and ferroniobium are produced. Exploration work for pyrochlore and other mineral resources are being undertaken on other carbonatites, particularly at Catalao I in southeast Goias and at Tapira and Serra Negra in western Minas Gerais. Annual production and export from the Barreiro deposit are about 8,000 metric tons of pyrochlore concentrate containing about 60 percent Nb205 and about 2,700 metric tons of ferroniobium with 63 percent Nb2O5. The annual production capacity of the Barreiro plant is 18,000 tons of concentrate and 4,000 tons of ferroniobium. Ore reserves of the Barreiro deposit in all categories are 380 million tons with percent Nb2O5. Annual production of tantalite-columbite from the Sao Joao del Rei district, most of which is exported to the United States, is about 290 tons, of which about 79 percent is tantalite and about percent is columbite. Reserves of tantalite-columbite in the Sao Joao del Rei district are about 43,000 tons of proved and 73,000 tons of probable ore.

  3. Grain boundary niobium carbides in Inconel 718

    SciTech Connect

    Gao, M.; Wei, R.P.

    1997-12-15

    A coordinated, multidisciplinary investigation was conducted to determine the mechanisms and rate controlling processes for environmentally assisted crack growth under sustained (static) loading in Inconel 718 at elevated temperatures. The results showed that oxygen had a significant influence on crack growth, increasing the crack growth rate, for example, by nearly four orders of magnitude at 973 K. Based on results from the companion surface chemical and metallurgical studies, it was suggested that the mechanism for crack growth enhancement by oxygen was the formation and fracture of a brittle niobium oxide (Nb{sub 2}O{sub 5}-type) film on the grain boundary surfaces. The Nb came principally from the oxidation and decomposition of NbC (or Nb-rich carbides) at the grain boundaries, and crack growth was controlled by the rate of oxidation and decomposition of these carbides. Because there was extensive oxidation of the primary NbC, these carbides were implicitly considered to be the primary source of Nb. Although these carbides were large and contained substantial amounts of Nb, they were too few and spaced too far apart to be of concern (averaging one NbC for two grain boundary facets and spaced about 25 {micro}m apart). To wit, whether the freed Nb could diffuse over such a large distance and be oxidized to support the postulated mechanism for crack growth? The presence of other Nb-rich carbides elsewhere on the grain boundaries, or other sources for Nb, therefore, needs to be re-examined and is the focus of this study. In this paper, the results of a study of grain boundary niobium carbides and their distribution in Inconel 718 are reported, and are discussed in terms of their contribution to crack growth.

  4. Recent developments in high purity niobium metal production at CBMM

    NASA Astrophysics Data System (ADS)

    Abdo, Gustavo Giovanni Ribeiro; Sousa, Clovis Antonio de Faria; Guimarães, Rogério Contato; Ribas, Rogério Marques; Vieira, Alaércio Salvador Martins; Menezes, Andréia Duarte; Fridman, Daniel Pallos; Cruz, Edmundo Burgos

    2015-12-01

    CBMM is a global supplier of high quality niobium products including pure niobium, the focus of this paper. CBMM's position has been consolidated over three decades of producing high purity niobium metal ingots. The company supplies, among other products, commercial and reactor grade niobium ingots. One of the main uses of CBMM's ingots is for the manufacture of particle accelerators (superconducting radio frequency - SRF - cavities), where the purity and homogeneity of niobium metal is essentially important for good performance. CBMM constantly strives to improve process controls and product quality, and is currently implementing innovations in production, research and development to further improve ingot quality. The main aim is to reduce the content of interstitial elements, such as nitrogen (N), oxygen (O), carbon (C), and hydrogen (H), starting with the raw materials through the final step of ingot production. CBMM held the first trial to produce the world's largest-diameter niobium ingot (as cast 535 mm). The results of this initial trial presented very low levels of interstitial impurities (N, O, C, H), allowing the achievement of residual resistivity ratio (RRR) values very close to 300 in a six-melt process in an electron beam furnace. These values were reached with 850 ppm of tantalum. SRF cavities will be produced with this material in order to study the effect of low impurities and high RRR on the Q factor and accelerating gradient.

  5. Titanium-niobium, a new finishing wire alloy.

    PubMed

    Dalstra, M; Denes, G; Melsen, B

    2000-02-01

    The mechanical properties of the newly introduced titanium-niobium finishing wires were investigated. Both in bending and torsional loading mode, the stiffness, yield point, post-yield behavior, and springback of titanium-niobium wires were experimentally determined and compared to those of equally sized stainless steel wires. The experimentally obtained values were also validated with theoretical values from engineering formulas of cantilever deformations. The ratios for these parameters for the two materials proved to be different in bending and torsion. The stiffness of titanium-niobium in bending is roughly half of that of stainless steel, whereas in torsion it is roughly one-third. These characteristics enable the clinician to use titanium-niobium for creative bends without the excessive force levels of steel wires. The springback of titanium-niobium in bending is 14% lower than that of steel, whereas in torsion it is about the same or even slightly higher than that of steel, thus making it possible to utilize the wire for even major third-order corrections. Finally, the weldability of titanium-niobium wires was found to be good, so it is possible to weld wires of different dimensions together for the generation of differentiated force systems. PMID:11168279

  6. Field determination of microgram quantities of niobium in rocks

    USGS Publications Warehouse

    Ward, F.N.; Marranzino, A.P.

    1955-01-01

    A rapid, simple, and moderately accurate method was needed for the determination of traces of niobium in rocks. The method developed is based on the reaction of niobium(V) with thiocyanate ion in a 4M hydrochloric acid and 0.5M tartaric acid medium, after which the complex is extracted with ethyl ether. The proposed procedure is applicable to rocks containing from 50 to 2000 p.p.m. of niobium, and, with modifications, can be used on rocks containing larger amounts. Five determinations on two rocks containing 100 p.p.m. or less of niobium agree within 5 p.p.m. of the mean, and the confidence limits at the 95% level are, respectively, ??6 and ??4 p.p.m. The addition of acetone to the ether extract of the niobium thiocyanate inhibits the polymerization of the thiocyanate ion and stabilizes the solution for at least 20 hours. The proposed procedure permits the determination of 20 ?? of niobium in the presence of 1000 ?? of iron, titanium, or uranium; 500 ?? of vanadium; or 100 ?? of tungsten or molybdenum or both.

  7. Recent developments in high purity niobium metal production at CBMM

    SciTech Connect

    Abdo, Gustavo Giovanni Ribeiro Sousa, Clovis Antonio de Faria Guimarães, Rogério Contato Ribas, Rogério Marques Vieira, Alaércio Salvador Martins Menezes, Andréia Duarte Fridman, Daniel Pallos Cruz, Edmundo Burgos

    2015-12-04

    CBMM is a global supplier of high quality niobium products including pure niobium, the focus of this paper. CBMM’s position has been consolidated over three decades of producing high purity niobium metal ingots. The company supplies, among other products, commercial and reactor grade niobium ingots. One of the main uses of CBMM’s ingots is for the manufacture of particle accelerators (superconducting radio frequency – SRF – cavities), where the purity and homogeneity of niobium metal is essentially important for good performance. CBMM constantly strives to improve process controls and product quality, and is currently implementing innovations in production, research and development to further improve ingot quality. The main aim is to reduce the content of interstitial elements, such as nitrogen (N), oxygen (O), carbon (C), and hydrogen (H), starting with the raw materials through the final step of ingot production. CBMM held the first trial to produce the world’s largest-diameter niobium ingot (as cast 535 mm). The results of this initial trial presented very low levels of interstitial impurities (N, O, C, H), allowing the achievement of residual resistivity ratio (RRR) values very close to 300 in a six-melt process in an electron beam furnace. These values were reached with 850 ppm of tantalum. SRF cavities will be produced with this material in order to study the effect of low impurities and high RRR on the Q factor and accelerating gradient.

  8. Determination of niobium in the parts per million range in rocks

    USGS Publications Warehouse

    Grimaldi, F.S.

    1960-01-01

    A modified niobium thiocyanate spectrophotometric procedure relatively insensitive to titanium interference is presented. Elements such as tungsten, molybdenum, vanadium, and rhenium, which seriously interfere in the spectrophotometric determination of niobium, are separated by simple sodium hydroxide fusion and leach; iron and magnesium are used as carriers for the niobium. Tolerance limits are given for 28 elements in the spectrophotometric method. Specific application is made to the determination of niobium in the parts per million range in rocks. The granite G-1 contains 0.0022% niobium and the diabase W-1 0.00096% niobium.

  9. Thermal transport properties of niobium and some niobium base alloys from 80 to 1600/sup 0/K

    SciTech Connect

    Moore, J.P.; Graves, R.S.; Williams, R.K.

    1980-01-01

    The electrical resistivities and absolute Seebeck coefficients of 99.8 at. % niobium with a RRR of 36, Nb-4.8 at. % W, Nb-5 at. % Mo, Nb-10 at. % Mo, and Nb-2.4 at. % Mo-2.4 at. % Zr were measured from 80 to 1600/sup 0/K, and the thermal conductivities of the niobium and Nb-5 at. % W were measured from 80 to 1300/sup 0/K. A technique is described for measuring the electrical resistivity and Seebeck coefficient of a specimen during radial heat flow measurements of the thermal conductivity. The transport property results, which had uncertainties of +-0.4%for electrical resistivity and +-1.4% for thermal conductivity, showed the influence of tungsten and molybdenum solutes on the transport properties of niobium and were used to obtain the electronic Lorenz function of pure niobium, which was found to approach the Sommerfeld value at high temperatures.

  10. Physical and Mechanical Properties of Niobium for SRF Science and Technology

    SciTech Connect

    Ganapati Rao Myneni

    2006-10-31

    Optimized mechanical and physical properties of high purity niobium are crucial for obtaining high performance SRF particle beam accelerator structures consistently. This paper summarizes these important material properties for both high purity polycrystalline and single crystal niobium.

  11. 40 CFR 88.302-94 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 CFR part 86 also apply to this part. All terms used in this part, but not defined in this section or in § 88.302-93 and 40 CFR part 86 shall have the meaning assigned to them in the Clean Air Act.../engine conversion configuration pursuant to the requirements of 40 CFR part 86 and this part 88....

  12. 34 CFR 361.88 - Reporting requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 2 2014-07-01 2013-07-01 true Reporting requirements. 361.88 Section 361.88 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION STATE VOCATIONAL REHABILITATION SERVICES PROGRAM...

  13. 34 CFR 361.88 - Reporting requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 2 2012-07-01 2012-07-01 false Reporting requirements. 361.88 Section 361.88 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION STATE VOCATIONAL REHABILITATION SERVICES PROGRAM Evaluation Standards and Performance Indicators...

  14. 34 CFR 361.88 - Reporting requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 2 2013-07-01 2013-07-01 false Reporting requirements. 361.88 Section 361.88 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION STATE VOCATIONAL REHABILITATION SERVICES PROGRAM...

  15. 45 CFR 88.1 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Purpose. 88.1 Section 88.1 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION ENSURING THAT DEPARTMENT OF HEALTH AND HUMAN... referred to as the federal healthcare conscience protection statutes). These statutory provisions...

  16. 49 CFR 230.88 - Throttles.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Throttles. 230.88 Section 230.88 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Throttles...

  17. 9 CFR 88.2 - General information.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false General information. 88.2 Section 88.2 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE INTERSTATE TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS COMMERCIAL TRANSPORTATION...

  18. 40 CFR 88.302-94 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 CFR part 86 also apply to this part. All terms used in this part, but not defined in this section or in § 88.302-93 and 40 CFR part 86 shall have the meaning assigned to them in the Clean Air Act.../engine conversion configuration pursuant to the requirements of 40 CFR part 86 and this part 88....

  19. 36 CFR 223.88 - Bidding methods.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Bidding methods. 223.88 Section 223.88 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS...

  20. 36 CFR 223.88 - Bidding methods.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Bidding methods. 223.88 Section 223.88 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS...

  1. 36 CFR 223.88 - Bidding methods.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Bidding methods. 223.88 Section 223.88 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS...

  2. 38 CFR 8.8 - Health requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false Health requirements. 8.8... INSURANCE Reinstatement § 8.8 Health requirements. National Service life insurance on any plan may be... month for which the unpaid premium was due, provided the applicant be in as good health on the date...

  3. 38 CFR 8.8 - Health requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false Health requirements. 8.8... INSURANCE Reinstatement § 8.8 Health requirements. National Service life insurance on any plan may be... month for which the unpaid premium was due, provided the applicant be in as good health on the date...

  4. 38 CFR 8.8 - Health requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Health requirements. 8.8... INSURANCE Reinstatement § 8.8 Health requirements. National Service life insurance on any plan may be... month for which the unpaid premium was due, provided the applicant be in as good health on the date...

  5. 38 CFR 8.8 - Health requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false Health requirements. 8.8... INSURANCE Reinstatement § 8.8 Health requirements. National Service life insurance on any plan may be... month for which the unpaid premium was due, provided the applicant be in as good health on the date...

  6. 38 CFR 8.8 - Health requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false Health requirements. 8.8... INSURANCE Reinstatement § 8.8 Health requirements. National Service life insurance on any plan may be... month for which the unpaid premium was due, provided the applicant be in as good health on the date...

  7. 40 CFR 88.302-94 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 CFR part 86 also apply to this part. All terms used in this part, but not defined in this section or in § 88.302-93 and 40 CFR part 86 shall have the meaning assigned to them in the Clean Air Act.../engine conversion configuration pursuant to the requirements of 40 CFR part 86 and this part 88....

  8. 7 CFR 966.88 - Agents.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Agents. 966.88 Section 966.88 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order...

  9. 36 CFR 223.88 - Bidding methods.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Bidding methods. 223.88... Sale Contracts Advertisement and Bids § 223.88 Bidding methods. (a) Competitive sales of National Forest timber shall be offered through either sealed or oral auction bidding. The method chosen for...

  10. 38 CFR 4.88 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false 4.88 Section 4.88 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS SCHEDULE FOR RATING DISABILITIES Disability Ratings Infectious Diseases, Immune Disorders and Nutritional Deficiencies §...

  11. 42 CFR 88.1 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Definitions. 88.1 Section 88.1 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND... Conditions (4) Cancers: This list includes those individual cancer types specified in Table 1,...

  12. 7 CFR 905.88 - Personal liability.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Personal liability. 905.88 Section 905.88 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE ORANGES, GRAPEFRUIT, TANGERINES, AND TANGELOS GROWN IN FLORIDA...

  13. 7 CFR 905.88 - Personal liability.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Personal liability. 905.88 Section 905.88 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ORANGES, GRAPEFRUIT, TANGERINES, AND TANGELOS GROWN IN FLORIDA...

  14. 7 CFR 905.88 - Personal liability.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Personal liability. 905.88 Section 905.88 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE ORANGES, GRAPEFRUIT, TANGERINES, AND TANGELOS GROWN IN FLORIDA...

  15. 45 CFR 96.88 - Administrative costs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Administrative costs. 96.88 Section 96.88 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION BLOCK GRANTS Low-income Home Energy... planning and administering the low-income home energy assistance program shall be 20 percent of...

  16. 40 CFR 98.88 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... meaning given in the Clean Air Act and subpart A of this part. ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Definitions. 98.88 Section 98.88 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED)...

  17. 40 CFR 88.201-94 - Scope.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... other states pursuant to compliance with section 249 of the Clean Air Act, as amended in 1990. (b... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Scope. 88.201-94 Section 88.201-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED)...

  18. 40 CFR 88.201-94 - Scope.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... other states pursuant to compliance with section 249 of the Clean Air Act, as amended in 1990. (b... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Scope. 88.201-94 Section 88.201-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED)...

  19. 40 CFR 88.201-94 - Scope.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... other states pursuant to compliance with section 249 of the Clean Air Act, as amended in 1990. (b... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Scope. 88.201-94 Section 88.201-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED)...

  20. 40 CFR 88.201-94 - Scope.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... other states pursuant to compliance with section 249 of the Clean Air Act, as amended in 1990. (b... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Scope. 88.201-94 Section 88.201-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED)...

  1. 40 CFR 88.201-94 - Scope.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... other states pursuant to compliance with section 249 of the Clean Air Act, as amended in 1990. (b... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Scope. 88.201-94 Section 88.201-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED)...

  2. 7 CFR 982.88 - Amendments.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Amendments. 982.88 Section 982.88 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE HAZELNUTS GROWN IN OREGON...

  3. 7 CFR 982.88 - Amendments.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Amendments. 982.88 Section 982.88 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE HAZELNUTS GROWN IN OREGON...

  4. 7 CFR 982.88 - Amendments.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Amendments. 982.88 Section 982.88 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE HAZELNUTS GROWN IN OREGON...

  5. 7 CFR 982.88 - Amendments.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Amendments. 982.88 Section 982.88 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE HAZELNUTS GROWN IN OREGON...

  6. 7 CFR 982.88 - Amendments.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Amendments. 982.88 Section 982.88 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE HAZELNUTS GROWN IN OREGON...

  7. 7 CFR 984.88 - Agents.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Agents. 984.88 Section 984.88 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE WALNUTS GROWN IN CALIFORNIA Order...

  8. 7 CFR 984.88 - Agents.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Agents. 984.88 Section 984.88 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE WALNUTS GROWN IN CALIFORNIA Order...

  9. 7 CFR 984.88 - Agents.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Agents. 984.88 Section 984.88 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE WALNUTS GROWN IN CALIFORNIA Order...

  10. 7 CFR 984.88 - Agents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Agents. 984.88 Section 984.88 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE WALNUTS GROWN IN CALIFORNIA Order...

  11. 7 CFR 984.88 - Agents.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Agents. 984.88 Section 984.88 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE WALNUTS GROWN IN CALIFORNIA Order...

  12. Niobium-based superconducting nano-device fabrication using all-metal suspended masks

    NASA Astrophysics Data System (ADS)

    Samaddar, S.; van Zanten, D.; Fay, A.; Sacépé, B.; Courtois, H.; Winkelmann, C. B.

    2013-09-01

    We report a novel method for the fabrication of superconducting nano-devices based on niobium. The well-known difficulties of lithographic patterning of high-quality niobium are overcome by replacing the usual organic resist mask by a metallic one. The quality of the fabrication procedure is demonstrated by the realization and characterization of long and narrow superconducting lines and niobium-gold-niobium proximity SQUIDs.

  13. Structure and texture of electrolytic superconducting coatings of high-purity niobium

    NASA Astrophysics Data System (ADS)

    Kolosov, V. N.; Shevyrev, A. A.

    2014-08-01

    Modes of epitaxial growth of electrolytic superconducting coatings of high-purity niobium on substrates of niobium, molybdenum, and tungsten have been investigated. The dynamics of changes in the structure and texture of the coatings depending on the method of treatment of substrates, cathode current density, and thickness of the deposited niobium layer has been studied.

  14. Elucidating the Band Gap of Niobium Dioxide

    NASA Astrophysics Data System (ADS)

    O'Hara, Andrew; Vigil-Fowler, Derek; Louie, Steven G.; Demkov, Alexander A.

    2015-03-01

    Like VO2, niobium dioxide (NbO2) belongs to the family of transition metal oxides with a temperature-driven metal-to-insulator transition. However, NbO2 has received considerably less attention, and several open questions about the material remain. One such question, of both practical and fundamental importance, is the nature and size of the band gap in the low-temperature, distorted rutile phase with a range reported for the gap of 0.5 eV to 1.2 eV. In this work, we investigate the low-temperature phase, utilizing several methodologies - density functional theory within the standard local density approximation (LDA), LDA +U, hybrid functional, and the GW approximation, to better understand the physics of the band gap in NbO2. Comparisons of the calculations are made to recent experimental work on NbO2 utilizing photoemission spectroscopy and ellipsometry. This work is supported by DOE under the SciDAC program, the NSF, and SRC.

  15. Superconducting DC and RF Properties of Ingot Niobium

    SciTech Connect

    Pashupati Dhakal, Gianluigi Ciovati, Peter Kneisel, Ganapati Rao Myneni

    2011-07-01

    The thermal conductivity, DC magnetization and penetration depth of large-grain niobium hollow cylindrical rods fabricated from ingots, manufactured by CBMM subjected to chemical and heat treatment were measured. The results confirm the influence of chemical and heat-treatment processes on the superconducting properties, with no significant dependence on the impurity concentrations in the original ingots. Furthermore, RF properties, such as the surface resistance and quench field of the niobium rods were measured using a TE{sub 011} cavity. The hollow niobium rod is the center conductor of this cavity, converting it to a coaxial cavity. The quench field is limited by the critical heat flux through the rods' cooling channel.

  16. SRF niobium characterization using SIMS and FIB-TEM

    SciTech Connect

    Stevie, F. A.

    2015-12-04

    Our understanding of superconducting radio frequency (SRF) accelerator cavities has been improved by elemental analysis at high depth resolution and by high magnification microscopy. This paper summarizes the technique development and the results obtained on poly-crystalline, large grain, and single crystal SRF niobium. Focused ion beam made possible sample preparation using transmission electron microscopy and the images obtained showed a very uniform oxide layer for all samples analyzed. Secondary ion mass spectrometry indicated the presence of a high concentration of hydrogen and the hydrogen content exhibited a relationship with improvement in performance. Depth profiles of carbon, nitrogen, and oxygen did not show major differences with heat treatment. Niobium oxide less than 10 nm thick was shown to be an effective hydrogen barrier. Niobium with titanium contamination showed unexpected performance improvement.

  17. SRF niobium characterization using SIMS and FIB-TEM

    NASA Astrophysics Data System (ADS)

    Stevie, F. A.

    2015-12-01

    Our understanding of superconducting radio frequency (SRF) accelerator cavities has been improved by elemental analysis at high depth resolution and by high magnification microscopy. This paper summarizes the technique development and the results obtained on poly-crystalline, large grain, and single crystal SRF niobium. Focused ion beam made possible sample preparation using transmission electron microscopy and the images obtained showed a very uniform oxide layer for all samples analyzed. Secondary ion mass spectrometry indicated the presence of a high concentration of hydrogen and the hydrogen content exhibited a relationship with improvement in performance. Depth profiles of carbon, nitrogen, and oxygen did not show major differences with heat treatment. Niobium oxide less than 10 nm thick was shown to be an effective hydrogen barrier. Niobium with titanium contamination showed unexpected performance improvement.

  18. Precipitation of hydrides in high purity niobium after different treatments

    SciTech Connect

    Barkov, F.; Romanenko, A.; Trenikhina, Y.; Grassellino, A.

    2013-01-01

    Precipitation of lossy non-superconducting niobium hydrides represents a known problem for high purity niobium in superconducting applications. Using cryogenic optical and laser confocal scanning microscopy we have directly observed surface precipitation and evolution of niobium hydrides in samples after different treatments used for superconducting RF cavities for particle acceleration. Precipitation is shown to occur throughout the sample volume, and the growth of hydrides is well described by the fast diffusion-controlled process in which almost all hydrogen is precipitated at $T=140$~K within $\\sim30$~min. 120$^{\\circ}$C baking and mechanical deformation are found to affect hydride precipitation through their influence on the number of nucleation and trapping centers.

  19. Interfacial fracture toughness of alumina/niobium systems

    SciTech Connect

    Stout, M.G. ); O'Dowd, N.P.; Shih, C.F. . Div. of Engineering)

    1991-01-01

    The interfacial fracture toughness of an alumina/niobium composite has been measured as a function of phase angle. The interface was formed by solid-state bonding bulk Coor's AD-999 fine-grain alumina with a commercial purity niobium at 1600{degrees}C for 0.5 hr under a pressure of 10.5 MPa. The alumina/niobium system has a number of features which makes it ideal for an investigation of interfacial fracture toughness. From HREM data we estimate that the width of the interface is no more than 10 atomic planes. Furthermore the thermal expansion coefficients of the two materials differ by less than 5% so residual stresses due to the bonding process are small. Using symmetric and asymmetric four point bend specimens we have measured the fracture toughness of homogenous alumina and that of the alumina/niobium bimaterial in combinations of in-plane shear and tension. The fracture toughness of the homogenous alumina is relatively insensitive to the loading phase. The measured fracture toughness K{sub c} of the interface, however, depended strongly on phase angle. We were unable to obtain valid alumina/niobium interfacial toughness data at negative phase angles as the fracture initiates in the alumina and not at the interface. In symmetric bending at a phase angle {approx}5{degrees}, we measured a nominal interface toughness of 4.0 MPa{radical}m, comparable to the homogeneous alumina. We found that the toughness increased with loading phase angle to a value of K{sub c} {approx} 9 MPa{radical}m at a phase between 25{degrees} and 40{degrees}. Preliminary calculations and experiments suggest that this effect is due to an asymmetric stress distribution, with respect to the interface, and plastic deformation in the niobium. 12 refs., 9 figs., 1 tab.

  20. 40 CFR 88.303-93 - Abbreviations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) CLEAN-FUEL VEHICLES Clean-Fuel Fleet Program § 88.303-93 Abbreviations. The abbreviations in subpart A of this part and in 40 CFR part 86 apply to this subpart. The abbreviations in this section apply...

  1. STS-88 Mission Specialist Krikalev checks equipment

    NASA Technical Reports Server (NTRS)

    1998-01-01

    STS-88 Mission Specialist Sergei Konstantinovich Krikalev (center), a Russian cosmonaut, checks out equipment inside a module at the Space Station Processing Facility. Betsy Ahearn (left) and James Burrows, with Boeing, assist him. Mission STS-88 is targeted for launch on Dec. 3, 1998. It is the first U.S. flight for the assembly of the International Space Station and will carry the Unity connecting module.

  2. Effect of Surface Flow on Topography in Niobium Electropolishing

    SciTech Connect

    M.J. Kelley, C.E. Reece, L. Zhao

    2011-03-01

    Electropolishing (EP) is reliably delivering improved performance of multi-celled niobium SRF accelerator cavities, attributed to the smoother surface obtained. This superior leveling is a consequence of an etchant concentration gradient layer that arises in the HF-H2SO4 electrolyte adjacent to the niobium surface during polishing. Electrolyte circulation raises the prospect that fluid flow adjacent to the surface might affect the diffusion layer and impair EP performance. In this study, preliminary bench-top experiments with a moving electrode apparatus were conducted. We find that flow conditions approximating cavity EP show no effects attributable to depletion layer disruption.

  3. Study of AC/RF properties of SRF ingot niobium

    SciTech Connect

    Dhakal, Pashupati; Tsindlekht, Menachem I; Genkin, Valery M; Ciovati, Gianluigi; Myneni, Ganapati Rao

    2013-09-01

    In an attempt to correlate the performance of superconducting radiofrequency cavities made of niobium with the superconducting properties, we present the results of the magnetization and ac susceptibility of the niobium used in the superconducting radiofrequency cavity fabrication. The samples were subjected to buffer chemical polishing (BCP) surface and high temperature heat treatments, typically applied to the cavities fabrications. The analysis of the results show the different surface and bulk ac conductivity for the samples subjected to BCP and heat treatment. Furthermore, the RF surface impedance is measured on the sample using a TE011 microwave cavity for a comparison to the low frequency measurements.

  4. PROCESS OF PRODUCING A NIOBIUM-TIN COMPOUND

    DOEpatents

    Zegler, S.T.; Darby, J.B. Jr.

    1963-04-01

    This patent deals with a process of preparing pure Nb/sub 3/Sn. The process comprises heating powders of niobium and excess tin to 900 to 1000 deg C, whereby niobium reacts with the molten tin under the formation of Nb/sub 3/Sn; cooling and powdering the product and immersing the powder in concentrated hydrochloric acid for removal of excessive tin; separating the Nb/sub 3/Sn, rinsing and drying it and sintering it in an inert atmosphere at 900 to 1300 deg C. (AEC)

  5. America's Overview of Superconducting Science and Technology of Ingot Niobium

    SciTech Connect

    Gianluigi Ciovati, Peter Kneisel, Ganapati Myneni

    2011-03-01

    This contribution will present an overview of the results from R&D programs in the USA over the past four years towards the development of ingot Niobium as a viable alternative material to fabricate SRF cavities for particle accelerators. Activities at several laboratories and universities include fabrication, surface treatment and RF testing of single- and multi-cell cavities and studies of the thermal, mechanical and superconducting properties of samples from ingots of different purity. Possible advantages of ingot niobium over standard fine-grain (ASTM 6) are discussed and a streamlined treatment procedure to fully exploit those advantages is proposed.

  6. Niobium-Matrix-Composite High-Temperature Turbine Blades

    NASA Technical Reports Server (NTRS)

    Kaplan, Richard B.; Tuffias, Robert H.; La Ferla, Raffaele; Heng, Sangvavann; Harding, John T.

    1995-01-01

    High-temperture composite-material turbine blades comprising mainly niobium matrices reinforced with refractory-material fibers being developed. Of refractory fibrous materials investigated, FP-AL(2)0(3), tungsten, and polymer-based SiC fibers most promising. Blade of this type hollow and formed in nearly net shape by wrapping mesh of reinforcing refractory fibers around molybdenum mandrel, then using thermal-gradient chemical-vapor infiltration (CVI) to fill interstices with niobium. CVI process controllable and repeatable, and kinetics of both deposition and infiltration well understood.

  7. Two myeloid differentiation factor 88 (MyD88) isoforms identified in ducks.

    PubMed

    Cheng, Yuqiang; Wang, Hengan; Yan, Yaxian; Ding, Chan; Sun, Jianhe

    2015-10-01

    MyD88 is an adaptor protein involved in the interleukin-1 receptor-induced and Toll-like receptor (TLR)-induced activation of nuclear factor-κB (NF-κB). In this study, we identified two isoforms of MyD88 gene, designated DuMyD88-X1 and DuMyD88-X2, from duck cells. Both variants were determined to have a death domain at the N-terminal and a Toll/IL-1R (TIR) domain at the C-terminal; however, the TIR domain of DuMyD88-X2 was incomplete and was 81 amino acids shorter than DuMyD88-X1. Quantitative real-time reverse transcription PCR revealed broad expression of both MyD88s. During Newcastle disease virus (NDV) challenge experiments, expression of the two genes increased significantly, with DuMyD88-X1 having a larger amplitude and longer duration. Overexpression of DuMyD88-X1 and DuMyD88-X2 induced the activation of NF-κB and IL-6 in vitro, suggesting that DuMyD88-X1 and DuMyD88-X2 may be important in the innate immune response. The results verify the existence of a MyD88-dependent signaling pathway in ducks and contribute to understanding the potential role of MyD88s in the innate immune response. PMID:26004012

  8. Niobium enrichment and environmental enhancement of creep crack growth in nickel-base superalloys

    SciTech Connect

    Gao, M.; Wei, R.P.; Dwyer, D.J.

    1995-04-15

    In this paper, the possible role of niobium in the environmental enhancement of creep crack growth in nickel-base superalloys is further examined. The examination included (1) surface enrichment of Nb in a commercial Inconel 718; (2) a source of niobium and its interaction with oxygen; (3) preferential oxidation of Nb at the crack tip, and (4) correlations between environmental sensitivity and niobium concentration of nickel-base superalloys from the literature. The role of niobium was suggested by recent X-ray photoelectron spectroscopic (XPS) studies. The XPS studies show a significant increase in the concentration of niobium on the (001) surface of an Inconel 718 single crystal after heating at temperatures above 775 K. Considerable segregation of niobium was also found on the grain boundaries of a thermally aged commercial (polycrystalline) Inconel 718. The CCGR data showed significant enhancement by oxygen and water vapor at temperatures of 800--975 K where niobium enrichment occurred.

  9. Variation of Mechanical Properties of High RRR And Reactor Grade Niobium With Heat Treatments

    SciTech Connect

    Ganapati Myneni; H. Umezawa

    2003-06-01

    Superconducting rf cavities used as accelerating structures in particle accelerators are made from high purity niobium with residual resistance ratios greater than 250. Reactor grade niobium is also used to make wave-guide and/or end group components for these accelerating structures. The major impurities in this type of niobium are interstitially dissolved gases such as hydrogen, nitrogen, and oxygen in addition to carbon. After fabricating the niobium accelerating structures, they are subjected to heat treatments for several hours in vacuum at temperatures of up to 900 C for degassing hydrogen or up to 1400 C for improving the thermal conductivity of niobium considerably. These heat treatments are affecting the mechanical properties of niobium drastically. In this paper the variation of the mechanical properties of high purity and reactor grade niobium with heat treatments in a vacuum of {approx} 10{sup -6} Torr and temperatures from 600 C to 1250 C for periods of 10 to 6 hours are presented.

  10. Carbon-supported and alumina-supported niobium sulfide catalysts

    SciTech Connect

    Allali, N.; Marie, A.M.; Danot, M.

    1995-10-01

    Few studies deal with the properties of niobium sulfide as a hydrodesulfurization catalyst. In this paper, the preparation of carbon-supported niobium sulfide catalysts was optimized concerning (i) the nature of the soluble precursor, (ii) the drying process, and (iii) the sulfurizing treatment, which was always performed under atmospheric pressure but for different H{sub 2}S-based flows and reaction temperatures. The activities of the best samples prepared with niobium oxalate as the impregnation salt, drying at room temperature, and presulfurization with N{sub 2}/H{sub 2}S at 400{degrees}C are superior to that of a supported MoS{sub 2} reference catalyst. Alumina-supported systems can be sulfurized only under more severe conditions (CS{sub 2} under pressure). After optimization of the sulfurization treatment (400{degrees}C, 10 h) the maximum activity obtained is significantly higher than that of a molybdenum sulfide reference catalyst. The catalytic activities of the various catalysts studied are related to their morphological and chemical characteristics using TPR and EXAFS measurements. The work illustrates the importance of the support and the sulfurization method on the genesis of a niobium sulfide active phase. 37 refs., 7 figs., 4 tabs.

  11. Stress dependent oxidation of sputtered niobium and effects on superconductivity

    NASA Astrophysics Data System (ADS)

    David Henry, M.; Wolfley, Steve; Monson, Todd; Clark, Blythe G.; Shaner, Eric; Jarecki, Robert

    2014-02-01

    We report on the suppression of room temperature oxidation of DC sputtered niobium films and the effects upon the superconductive transition temperature, Tc. Niobium was sputter-deposited on silicon dioxide coated 150 mm wafers and permitted to oxidize at room temperature and pressure for up to two years. Resistivity and stress measurements indicate that tensile films greater than 400 MPa resist bulk oxidation with measurements using transmission electron microscope, electron dispersive X-ray spectroscopy, x-ray photoelectric spectroscopy, and secondary ion mass spectrometry confirming this result. Although a surface oxide, Nb2O5, consumed the top 6-10 nm, we measure less than 1 at. % oxygen and nitrogen in the bulk of the films after the oxidation period. Tc measurements using a SQUID magnetometer indicate that the tensile films maintained a Tc approaching the dirty superconductive limit of 8.4 K after two years of oxidation while maintaining room temperature sheet resistance. This work demonstrates that control over niobium film stress during deposition can prevent bulk oxidation by limiting the vertical grain boundaries ability to oxidize, prolonging the superconductive properties of sputtered niobium when exposed to atmosphere.

  12. High-Q superconducting niobium cavities for gravitational wave detectors

    NASA Astrophysics Data System (ADS)

    de Paula, L. A. N.; Furtado, S. R.; Aguiar, O. D.; Oliveira, N. F., Jr.; Castro, P. J.; Barroso, J. J.

    2014-10-01

    The main purpose of this work is to optimize the electric Q-factor of superconducting niobium klystron cavities to be used in parametric transducers of the Mario Schenberg gravitational wave detector. Many cavities were manufactured from niobium with relatively high tantalum impurities (1420 ppm) and they were cryogenically tested to determine their resonance frequencies, unloaded electrical quality factors (Q0) and electromagnetic couplings. These cavities were closed with a flat niobium plate with tantalum impurities below 1000 ppm and an unloaded electrical quality factors of the order of 105 have been obtained. AC conductivity of the order of 1012 S/m has been found for niobium cavities when matching experimental results with computational simulations. These values for the Q-factor would allow the detector to reach the quantum limit of sensitivity of ~ 10-22 Hz-1/2 in the near future, making it possible to search for gravitational waves around 3.2 kHz. The experimental tests were performed at the laboratories of the National Institute for Space Research (INPE) and at the Institute for Advanced Studies (IEAv - CTA).

  13. Stress dependent oxidation of sputtered niobium and effects on superconductivity

    SciTech Connect

    David Henry, M. Wolfley, Steve; Monson, Todd; Clark, Blythe G.; Shaner, Eric; Jarecki, Robert

    2014-02-28

    We report on the suppression of room temperature oxidation of DC sputtered niobium films and the effects upon the superconductive transition temperature, T{sub c}. Niobium was sputter-deposited on silicon dioxide coated 150 mm wafers and permitted to oxidize at room temperature and pressure for up to two years. Resistivity and stress measurements indicate that tensile films greater than 400 MPa resist bulk oxidation with measurements using transmission electron microscope, electron dispersive X-ray spectroscopy, x-ray photoelectric spectroscopy, and secondary ion mass spectrometry confirming this result. Although a surface oxide, Nb{sub 2}O{sub 5}, consumed the top 6–10 nm, we measure less than 1 at. % oxygen and nitrogen in the bulk of the films after the oxidation period. T{sub c} measurements using a SQUID magnetometer indicate that the tensile films maintained a T{sub c} approaching the dirty superconductive limit of 8.4 K after two years of oxidation while maintaining room temperature sheet resistance. This work demonstrates that control over niobium film stress during deposition can prevent bulk oxidation by limiting the vertical grain boundaries ability to oxidize, prolonging the superconductive properties of sputtered niobium when exposed to atmosphere.

  14. Cu-Nb-Si (Copper-Niobium-Silicon)

    NASA Astrophysics Data System (ADS)

    Materials Science International Team MSIT

    This document is part of Subvolume C2 'Non-Ferrous Metal Systems. Part 2: Selected Copper Systems' of Volume 11 'Ternary Alloy Systems - Phase Diagrams, Crystallographic and Thermodynamic Data critically evaluated by MSIT®' of Landolt-Börnstein - Group IV 'Physical Chemistry'. It provides data of the ternary system Copper-Niobium-Silicon.

  15. Ordering in non-stoichiometric carbides of niobium and tantalum

    SciTech Connect

    Markhasev, B.I.; Pilipovskii, Yu. L.; Shamatov, Yu. M.; Svintsova, S.E.

    1986-03-01

    Ordering processes were studied in the nonstoichiometric carbides of Nb and Ta. A mechanism of slip transition was proposed for the ordering of NbC/sub 2/, accompanied by precipitation of niobium metal. A diagram of the restructuring of the fcc lattice of NbC to the bcc lattice of Nb is presented.

  16. High-Temperature Creep Behavior Of Fiber-Reinforced Niobium

    NASA Technical Reports Server (NTRS)

    Petrasek, Donald W.; Titran, Robert H.

    1990-01-01

    Study conducted to determine feasibility of using composite materials in advanced space power systems, described in 22-page report. Tungsten fibers reduce creep and mass in advanced power systems. Reinforcing niobium alloys with tungsten fibers increases their resistances to creep by factors of as much as 10.

  17. Superconducting niobium thin film slow-wave structures

    NASA Technical Reports Server (NTRS)

    Bautista, J. J.; Petty, S. M.; Allen, L. H.; Beasley, M. R.; Hammond, R. H.

    1983-01-01

    A superconducting comb structure as a slow-wave element in a traveling-wave maser will significantly improve maser noise temperature and gain by reducing the insertion loss. The results of the insertion loss measurements of superconducting niobium slow-wave structures subjected to maser operating conditions at X-Band frequencies are presented.

  18. Oxidation Behavior of Binary Niobium Alloys

    NASA Technical Reports Server (NTRS)

    Barrett, Charles A.; Corey, James L.

    1960-01-01

    This investigation concludes a study to determine the effects of up to 25 atomic percent of 55 alloying additions on the oxidation characteristics of niobium. The alloys were evaluated by oxidizing in an air atmosphere for 4 hours at 1000 C and 2 hours at 1200 C. Titanium and chromium improved oxidation resistance at both evaluation conditions. Vanadium and aluminum improved oxidation resistance at 1000 C, even though the V scale tended to liquefy and the Al specimens became brittle and the scale powdery. Copper, cobalt, iron, and iridium improved oxidation resistance at 1200 C. Other investigations report tungsten and molybdenum are protective up to about 1000 C, and tantalum at 1100 C. The most important factor influencing the rate of oxidation was the ion size of the alloy additions. Ions slightly smaller than the Nb(5+) ion are soluble in the oxide lattice and tend to lower the compressive stresses in the bulk scale that lead to cracking. The solubility of the alloying addition also depends on the valence to some extent. All of the elements mentioned that improve the oxidation resistance of Nb fit this size criterion with the possible exception of Al, whose extremely small size in large concentrations would probably lead to the formation of a powdery scale. Maintenance of a crack-free bulk scale for as long as possible may contribute to the formation of a dark subscale that ultimately is rate- controlling in the oxidation process. The platinum-group metals, especially Ir, appear to protect by entrapment of the finely dispersed alloying element by the incoming Nb2O5 metal-oxide interface. This inert metallic Ir when alloyed in a sufficient amount with Yb appears to give a ductile phase dispersed in the brittle oxide. This scale would then flow more easily to relieve the large compressive stresses to delay cracking. Complex oxide formation (which both Ti and Zr tend to initiate) and valence effects, which probably change the vacancy concentration in the scale

  19. First-principles calculations of niobium hydride formation in superconducting radio-frequency cavities

    SciTech Connect

    Ford, Denise C.; Cooley, Lance D.; Seidman, David N.

    2013-09-01

    Niobium hydride is suspected to be a major contributor to degradation of the quality factor of niobium superconducting radio-frequency (SRF) cavities. In this study, we connect the fundamental properties of hydrogen in niobium to SRF cavity performance and processing. We modeled several of the niobium hydride phases relevant to SRF cavities and present their thermodynamic, electronic, and geometric properties determined from calculations based on density-functional theory. We find that the absorption of hydrogen from the gas phase into niobium is exothermic and hydrogen becomes somewhat anionic. The absorption of hydrogen by niobium lattice vacancies is strongly preferred over absorption into interstitial sites. A single vacancy can accommodate six hydrogen atoms in the symmetrically equivalent lowest-energy sites and additional hydrogen in the nearby interstitial sites affected by the strain field: this indicates that a vacancy can serve as a nucleation center for hydride phase formation. Small hydride precipitates may then occur near lattice vacancies upon cooling. Vacancy clusters and extended defects should also be enriched in hydrogen, potentially resulting in extended hydride phase regions upon cooling. We also assess the phase changes in the niobium-hydrogen system based on charge transfer between niobium and hydrogen, the strain field associated with interstitial hydrogen, and the geometry of the hydride phases. The results of this study stress the importance of not only the hydrogen content in niobium, but also the recovery state of niobium for the performance of SRF cavities.

  20. 9 CFR 88.2 - General information.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... EQUINES FOR SLAUGHTER § 88.2 General information. (a) State governments may enact and enforce regulations... whether an individual or other entity found to transport equines to a slaughtering facility is subject to... who transported the equines information regarding the business of that individual or other...

  1. 45 CFR 88.3 - Applicability.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION ENSURING THAT DEPARTMENT OF HEALTH AND HUMAN...) The Department of Health and Human Services is required to comply with sections §§ 88.4(a), (b)(1... through the appropriations act for the Department of Health and Human Services is required to comply...

  2. 32 CFR 552.88 - Responsibilities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CEMETERIES REGULATIONS AFFECTING MILITARY RESERVATIONS Fort Lewis Land Use Policy § 552.88 Responsibilities... of Ft. Lewis Land Use Policy and area access procedures, and provide periodic updates through media. Act as interface, when necessary, to resolve community relations issues related to land...

  3. 32 CFR 552.88 - Responsibilities.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... CEMETERIES REGULATIONS AFFECTING MILITARY RESERVATIONS Fort Lewis Land Use Policy § 552.88 Responsibilities... of Ft. Lewis Land Use Policy and area access procedures, and provide periodic updates through media. Act as interface, when necessary, to resolve community relations issues related to land...

  4. 32 CFR 552.88 - Responsibilities.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... CEMETERIES REGULATIONS AFFECTING MILITARY RESERVATIONS Fort Lewis Land Use Policy § 552.88 Responsibilities... of Ft. Lewis Land Use Policy and area access procedures, and provide periodic updates through media. Act as interface, when necessary, to resolve community relations issues related to land...

  5. 32 CFR 552.88 - Responsibilities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CEMETERIES REGULATIONS AFFECTING MILITARY RESERVATIONS Fort Lewis Land Use Policy § 552.88 Responsibilities... of Ft. Lewis Land Use Policy and area access procedures, and provide periodic updates through media. Act as interface, when necessary, to resolve community relations issues related to land...

  6. 32 CFR 552.88 - Responsibilities.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... CEMETERIES REGULATIONS AFFECTING MILITARY RESERVATIONS Fort Lewis Land Use Policy § 552.88 Responsibilities... of Ft. Lewis Land Use Policy and area access procedures, and provide periodic updates through media. Act as interface, when necessary, to resolve community relations issues related to land...

  7. 40 CFR 88.302-93 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) CLEAN-FUEL VEHICLES Clean-Fuel Fleet Program § 88.302-93 Definitions. The definitions in 40 CFR part 86... is comprised of a truck-tractor and one or more pieces of trailered equipment. The truck-tractor is a..., and a means of coupling to a cargo carrying trailer(s). The truck-tractor itself is not designed...

  8. 36 CFR 223.88 - Bidding methods.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Bidding methods. 223.88... methods. (a) Competitive sales of National Forest timber shall be offered through either sealed or oral auction bidding. The method chosen for each sale will: (1) Insure open and fair competition, (2)...

  9. 40 CFR 88.302-93 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) CLEAN-FUEL VEHICLES Clean-Fuel Fleet Program § 88.302-93 Definitions. The definitions in 40 CFR part 86... is comprised of a truck-tractor and one or more pieces of trailered equipment. The truck-tractor is a..., and a means of coupling to a cargo carrying trailer(s). The truck-tractor itself is not designed...

  10. 40 CFR 88.302-93 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) CLEAN-FUEL VEHICLES Clean-Fuel Fleet Program § 88.302-93 Definitions. The definitions in 40 CFR part 86... is comprised of a truck-tractor and one or more pieces of trailered equipment. The truck-tractor is a..., and a means of coupling to a cargo carrying trailer(s). The truck-tractor itself is not designed...