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Sample records for bare high purity

  1. Performance and stability tests of bare high purity germanium detectors in liquid argon for the GERDA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Barnabe Heider, Marik

    2009-05-27

    GERDA will search for neutrinoless double beta decay of {sup 76}Ge by using a novel approach of bare germanium detectors in liquid argon (LAr). Enriched germanium detectors from the previous Heidelberg-Moscow and IGEX experiments have been reprocessed and will be deployed in GERDA Phase-I. At the center of this thesis project is the study of the performance of bare germanium detectors in cryogenic liquids. Identical detector performance as in vacuum cryostats (2.2 keV FWHM at 1.3 MeV) was achieved in cryogenic liquids with a new low-mass detector assembly and contacts. One major result is the discovery of a radiation induced leakage current (LC) increase when operating bare detectors with standard passivation layers in LAr. Charge collection and build-up on the passivation layer were identified as the origin of the LC increase. It was found that diodes without passivation do not exhibit this feature. Three month-long stable operation in LAr at {proportional_to} 5 pA LC under periodic gamma irradiation demonstrated the suitability of the modi ed detector design. Based on these results, all Phase-I detectors were reprocessed without passivation layer and subsequently successfully characterized in LAr in the GERDA underground Detector Laboratory. The mass loss during the reprocessing was {proportional_to}300 g out of 17.9 kg and the exposure above ground {proportional_to} 5 days. This results in a negligible cosmogenic background increase of {proportional_to} 5.10{sup -4} cts/(keV.kg.y) at {sup 76}Ge Q{sub {beta}}{sub {beta}} for {sup 60}Co and {sup 68}Ge. (orig.)

  2. Production of high purity radiothallium

    International Nuclear Information System (INIS)

    Lebowitz, E.; Greene, M.W.

    1976-01-01

    The method of producing high-purity thallium-201 for use as a myocardial scanning agent comprises the steps of irradiating a thallium target with protons to give the reaction 203 Tl(p,3n) 201 Pb, separating in ion exchange columns the lead from the thallium isotopes, permitting the lead to decay, and then purifying the thallium solution and converting the thallium present to thallous form in which it can be used

  3. Ductility of Ultra High Purity Copper

    OpenAIRE

    Fujiwara, S.; Abiko, K.

    1995-01-01

    The ductility of ultra-high purity copper at elevated temperatures was investigated : purity 99.9999% (6N) and 99.999999% (8N). Tensile tests were conducted at temperatures ranging from 293K to 1073K at strain rates of 4.2x10-5 s-1 in a high vacuum. The results are discussed in comparison with those for 99.9% (3N) copper. Ductility at intermediate temperatures was improved by an increase in purity. The temperature at which ductility dropped decreased with increases in purity. Even at the ultr...

  4. High purity silane and silicon production

    Science.gov (United States)

    Breneman, William C. (Inventor)

    1987-01-01

    Silicon tetrachloride, hydrogen and metallurgical silicon are reacted at about 400.degree.-600.degree. C. and at pressures in excess of 100 psi, and specifically from about 300 up to about 600 psi to form di- and trichlorosilane that is subjected to disproportionation in the presence of an anion exchange resin to form high purity silane. By-product and unreacted materials are recycled, with metallurgical silicon and hydrogen being essentially the only consumed feed materials. The silane product may be further purified, as by means of activated carbon or cryogenic distillation, and decomposed in a fluid bed or free space reactor to form high purity polycrystalline silicon and by-product hydrogen which can be recycled for further use. The process results in simplified waste disposal operations and enhances the overall conversion of metallurgical grade silicon to silane and high purity silicon for solar cell and semiconductor silicon applications.

  5. Shape rheocasting of high purity aluminium

    CSIR Research Space (South Africa)

    Curle, UA

    2011-03-01

    Full Text Available It is demonstrated experimentally that using the Council for Scientific and Industrial Research Rheo Casting System and high pressure die casting it is possible to semi-solid process and cast into a shape high purity aluminium without a...

  6. High-purity germanium crystal growing

    International Nuclear Information System (INIS)

    Hansen, W.L.; Haller, E.E.

    1982-10-01

    The germanium crystals used for the fabrication of nuclear radiation detectors are required to have a purity and crystalline perfection which is unsurpassed by any other solid material. These crystals should not have a net electrically active impurity concentration greater than 10 10 cm - 3 and be essentially free of charge trapping defects. Such perfect crystals of germanium can be grown only because of the highly favorable chemical and physical properties of this element. However, ten years of laboratory scale and commercial experience has still not made the production of such crystals routine. The origin and control of many impurities and electrically active defect complexes is now fairly well understood but regular production is often interrupted for long periods due to the difficulty of achieving the required high purity or to charge trapping in detectors made from crystals seemingly grown under the required conditions. The compromises involved in the selection of zone refining and crystal grower parts and ambients is discussed and the difficulty in controlling the purity of key elements in the process is emphasized. The consequences of growing in a hydrogen ambient are discussed in detail and it is shown how complexes of neutral defects produce electrically active centers

  7. Preserving high-purity 233U

    International Nuclear Information System (INIS)

    Krichinsky, Alan; Giaquinto, Joe; Canaan, Doug

    2016-01-01

    The MARC X Conference hosted a workshop for the scientific community to communicate needs for high-purity 233 U and its by-products in order to preserve critical items otherwise slated for downblending and disposal. Currently, only small portions of the U.S. holdings of separated 233 U are being preserved. However, many additional kilograms of 233 U (>97 % pure) still are destined to be disposed, and it is unlikely that this material will ever be replaced due to a lack of operating production capability. Summaries of information conveyed at the workshop and feedback obtained from the scientific community are presented herein. (author)

  8. Zone refining high-purity germanium

    International Nuclear Information System (INIS)

    Hubbard, G.S.; Haller, E.E.; Hansen, W.L.

    1977-10-01

    The effects of various parameters on germanium purification by zone refining have been examined. These parameters include the germanium container and container coatings, ambient gas and other operating conditions. Four methods of refining are presented which reproducibly yield 3.5 kg germanium ingots from which high purity (vertical barN/sub A/ - N/sub D/vertical bar less than or equal to2 x 10 10 cm -3 ) single crystals can be grown. A qualitative model involving binary and ternary complexes of Si, O, B, and Al is shown to account for the behavior of impurities at these low concentrations

  9. Neutron activation analysis of high purity metals

    International Nuclear Information System (INIS)

    Artem'ev, O.I.; Poznyak, V.L.; Stepanov, V.M.

    1990-01-01

    Methods of neutron-activation analysis of high-purity bismuth, lead, mercury and cadmium with the content of certain impurity elements at the level of 10 -6 -10 -11 mass% were developed. The suggested methods of radiochemical isolation of impurities from irradiated bismuth and lead differ from previously known ones in a higher quickness and lower labour consumption. The combination of vacuum distillation of mercury and cadmium (preconcentrating of impurities) and additional radiochemical separation provides possibility to carry out neutron activation analysis of representative samples of mercury and cadmium

  10. Highly Accurate Sensor for High-Purity Oxygen Determination Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this STTR effort, Los Gatos Research (LGR) and the University of Wisconsin (UW) propose to develop a highly-accurate sensor for high-purity oxygen determination....

  11. Processing to obtain high-purity gallium

    Science.gov (United States)

    Bautista, Renato G.

    2003-03-01

    Gallium has become increasingly popular as a substrate material for electronic devices. Aside from ore, gallium can be obtained from such industrial sources as the Bayer process caustic liquor that is a byproduct of bauxite processing, flue dust removed from the fume-collection system in plants that produce aluminum by the electrolytic process, zinc refinery residues, gallium scrap materials, and coal fly ash. The purification process for gallium can start with solvent-extraction processes where the concentrations of impurities, especially metals, are reduced to the ppm range. This article describes how ultra-purification techniques can be employed to reduce the undesirable impurities to the low ppb range. The various procedures described give an idea as to the extent of work needed to obtain and prepare high-purity gallium for electronic application.

  12. High Purity Smelting Technology for Ultra-high Strength Steels

    Directory of Open Access Journals (Sweden)

    JIANG Zhouhua

    2017-12-01

    Full Text Available Ultra-high strength steel with high tensile strength, good toughness, high specific strength, modulus and other characteristics are widely used in aviation, aerospace and national defense and other fields. Ultra-high strength steel is preferred material for aircraft and aero-engines and other aviation equipments. The application of ultra-high strength steel represents a country's highest level of steel research and production, and it is also an important symbol of the development of national science and technology and national defense industry. The development and application of high purity smelting technology for manufacture of ultra-high strength steels at domestic and overseas is briefly reviewed in the paper, and then the control ability about the impurity elements such as S, P, O and N in typical ultra-high strength steels, and the research status and development trend of non-metallic inclusions control are discussed. The progress in research work of high purity smelting technology for ultra-high strength steels carried out by the authors in recent years has been introduced, it shows that the control level of impurity elements and non-metallic inclusion has been greatly improved, and it also creates a new route for China to manufacture the ultra-high strength steel with high alloy, especially with high purity for ultra-high strength stainless steel, bearing steel and gear steel. Finally, the development direction of high purity smelting technology of ultra-high strength steel in China is pointed out.

  13. High purity tellurium production using dry refining processes

    Indian Academy of Sciences (India)

    purity) is purified using dry processes such as selective vapourization and zone melting in a thoroughly etched and cleaned quartz boat, under continuous flow of hydrogen (H2) gas. The tellurium ingot was quadruple zone refined (QZR) under continuous flow of H2 gas. Thus, the purified tellurium of ultra high purity (UHP) ...

  14. Production of High Purity Niobium Ingots at CBMM

    International Nuclear Information System (INIS)

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

    2011-01-01

    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.

  15. Effect of phosphorus on hot ductility of high purity iron

    International Nuclear Information System (INIS)

    Abiko, K.; Liu, C.M.; Ichikawa, M..; Suenaga, H.; Tanino, M.

    1995-01-01

    Tensile tests on high purity Fe-P alloys with 0, 0.05 and 0.1 mass%P were carried out at temperatures between 300 K and 1073 K to clarify the intrinsic effect of phosphorus on the mechanical properties of iron at elevated temperatures. Microstructures of as-quenched, interrupted and ruptured specimens were observed. Experimental results show that the addition of phosphorus causes a remarkable increase in proof stress of high purity iron at 300 K, but the increase in proof stress by phosphorus decreases with increasing test temperature. The strengthening effect of phosphorus reduces to zero at 1073 K. High purity iron and Fe-P alloys rupture at almost 100% reduction in area at the whole test temperatures. However, Fe-P alloys show much larger elongation at test temperatures above 773 K than high purity iron. The increased elongation of high purity iron by addition of phosphorus was shown to be related to the effect of phosphorus on dynamic recovery and recrystallization of iron as its intrinsic effect. (orig.)

  16. Development of high purity niobium material for superconducting cavities

    International Nuclear Information System (INIS)

    Umezawa, Hiroaki; Takeuchi, Koichi; Sakita, Kohei; Suzuki, Takafusa; Saito, Kenji; Noguchi, Shuichi.

    1993-01-01

    For the superconducting niobium cavities, issues of thermal quench and field emission have to be solved to achieve a high field gradient (>25MV/m) for TESLA (TeV Energy Superconducting Linear Accelerator). In order to overcome the quench, upgrading of thermal conductivity of niobium material at the low temperature is very important. On the reduction of the field emission not only dust particles but also defect, impurity and inhomogeneity should be considered. Therefore development of high purity niobium material is very important to solve these issues. This paper describes the our latest R and D for high purity niobium material. (author)

  17. Effect of Phosphorus on Hot Ductility of High Purity Iron

    OpenAIRE

    Abiko, K.; Liu, C.-M.; Ichikawa, M.; Suenaga, H.; Tanino, M.

    1995-01-01

    Tensile tests on high purity Fe-P alloys with 0, 0.05 and 0.1 mass%P were carried out at temperatures between 300 K and 1073 K to clarify the intrinsic effect of phosphorus on the mechanical properties of iron at elevated temperatures. Microstructures of as-quenched, interrupted and ruptured specimens were observed. Experimental results show that the addition of phosphorus causes a remarkable increase in proof stress of high purity iron at 300 K, but the increase in proof stress by phosphorus...

  18. Thermocurrent dosimetry with high purity aluminum oxide

    International Nuclear Information System (INIS)

    Fullerton, G.D.; Cameron, J.R.; Moran, P.R.

    1976-01-01

    The application of thermocurrent (TC) to ionizing radiation dosimetry was studied. It was shown that TC in alumina (Al 2 O 3 ) has properties that are suited to personnel dosimetry and environmental monitoring. TC dosimeters were made from thin disks of alumina. Aluminum electrodes were evaporated on each side: on one face a high voltage electrode and on the opposite face a measuring electrode encircled by a guard ring. Exposure to ionizing radiation resulted in stored electrons and holes in metastable trapping sites. The signal was read-out by heating the dosimeter with a voltage source and picnometer connected in series between the opposite electrodes. The thermally remobilized charge caused a transient TC. The thermogram, TC versus time or temperature, is similar to a TL glow curve. Either the peak current or the integrated current is a measure of absorbed dose. Six grades of alumina were studied from a total of four commercial suppliers. All six materials displayed radiation induced TC signals. Sapphire of uv-grade quality from the Adolf Meller Co. (AM) had the best dosimetry properties of those investigated. Sources of interference were studied. Thermal fading, residual signal and radiation damage do not limit TC dosimetry. Ultraviolet light can induce a TC response but it is readily excluded with uv-opaque cladding. Improper surface preparation prior to electrode evaporation was shown to cause interference. A spurious TC signal resulted from polarization of surface contaminants. Spurious TC was reduced by improved cleaning prior to electrode application. Polished surfaces resulted in blocking electrodes and caused a sensitivity shift due to radiation induced thermally activated polarization. This was not observed with rough cut surfaces

  19. Low cost routes to high purity silicon and derivatives thereof

    Science.gov (United States)

    Laine, Richard M; Krug, David James; Marchal, Julien Claudius; Mccolm, Andrew Stewart

    2013-07-02

    The present invention is directed to a method for providing an agricultural waste product having amorphous silica, carbon, and impurities; extracting from the agricultural waste product an amount of the impurities; changing the ratio of carbon to silica; and reducing the silica to a high purity silicon (e.g., to photovoltaic silicon).

  20. Multielement trace determination in high purity advanced ceramics ...

    Indian Academy of Sciences (India)

    Unknown

    ing electrothermal atomic absorption spectrometry (SS. ET AAS) applied to the determination of trace elements in high purity advanced ceramics. The application of SS. ET AAS has been described together with the method of inductively coupled plasma optical emission spectro- metry with electrothermal evaporation (ETV ...

  1. Multielement trace determination in high purity advanced ceramics ...

    Indian Academy of Sciences (India)

    Besides their application by industry they are appropriate to be used for the validation of special methods used for trace determination in accordance with high purity materials. This is demonstrated, for example, on ultrapure silicon carbide which was analysed by solid sampling electrothermal atomic absorption spectrometry ...

  2. High purity tellurium production using dry refining processes

    Indian Academy of Sciences (India)

    Unknown

    Centre for Materials for Electronics Technology (C-MET), IDA Phase II, Cherlapally, HCL Post, Hyderabad 500 051,. India. Abstract. ... tellurium of ultra high purity (UHP) grade is analysed for 60 impurity elements in the periodic table using glow discharge ... activity coefficient and M the molecular weight of impu- rity (i) and ...

  3. High purity materials as targets for radioisotope production: Needs ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 28; Issue 4. High purity materials as targets for radioisotope production: Needs and challenges ... Application of radioisotopes in medicine has given birth to a new branch, viz. nuclear medicine, wherein radioisotopes are used extensively in the diagnosis and treatment ...

  4. High purity liquid phase epitaxial gallium arsenide nuclear radiation detector

    International Nuclear Information System (INIS)

    Alexiev, D.; Butcher, K.S.A.

    1991-11-01

    Surface barrier radiation detector made from high purity liquid phase epitaxial gallium arsenide wafers have been operated as X- and γ-ray detectors at various operating temperatures. Low energy isotopes are resolved including 241 Am at 40 deg C. and the higher gamma energies of 235 U at -80 deg C. 15 refs., 1 tab., 6 figs

  5. Analytical challenges in characterization of high purity materials

    Indian Academy of Sciences (India)

    A number of analytical methodologies are being used in the author's laboratory for carrying out trace elemental analysis as a part of chemical quality control. Quite a good number of analytical challenges with specific reference to the characterization of high purity materials of relevance to nuclear technology were addressed ...

  6. Preparation of high purity tellurium by zone refining

    Indian Academy of Sciences (India)

    This paper describes purification process of tellurium metal using zone refining technique under high purity hydrogen gas ambient in normal room environment. Process automation by newly designed stepper motor drive and allied process control instruments circumvent the complexity of electrical motors. It is observed that ...

  7. Surface passivation of high purity granular metals: zinc, cadmium, lead

    Directory of Open Access Journals (Sweden)

    Pirozhenko L. A.

    2017-10-01

    Full Text Available For the high purity metals (99.9999%, such as zinc, cadmium, and lead, which are widely used as initial components in growing semiconductor and scintillation crystals (CdTe, CdZnTe, ZnSe, (Cd, Zn, Pb WO4, (Cd, Zn, Pb MoO4 et al., it is very important to ensure reliable protection of the surface from oxidation and adsorption of impurities from the atmosphere. The specific features of surface passivation of high purity cadmium, lead and zinc are not sufficiently studied and require specific methodologies for further studies. The use of organic solutions in the schemes of chemical passivation of the investigated metals avoids hydrolysis of the obtained protective films. The use of organic solvents with pure cation and anion composition as the washing liquid prevents chemisorption of ions present in the conventionally used distilled water. This keeps the original purity of the granular metals. Novel compositions of etchants and etching scheme providing simultaneous polishing and passivation of high purity granular Zn, Cd and Pb are developed. Chemical passivation allows storing metals in the normal atmospheric conditions for more than half a year for Zn and Cd and up to 30 days for Pb without changing the state of the surface. The use of the glycerol-DMF solution in the processes for obtaining Pb granules provides self-passivation of metal surfaces and eliminates the additional chemical processing while maintaining the quality of corrosion protection.

  8. Demands made on high-purity copper for special purposes

    International Nuclear Information System (INIS)

    Roettges, D.

    1977-01-01

    The properties (electrical resistivity, residual impurities) of high-purity copper produced on a technical scale are reported as well as its practical applications. The paper discusses a high-oxygen copper (SV) with low residual resistivity at low temperatures and an oxygen-free (hydrogen-stable) copper (BE electronic) with low gas content. The SV quality has been specially developed for use as stabilizer in superconductors while the BE quality is used in high and ultrahigh vacuum. (GSC) [de

  9. The Research about Preparation of High Purity Hexachlorodisilane

    Science.gov (United States)

    Wan, Ye; Zhao, Xiong; Yan, Dazhou; Zhao, Yu; Guo, Shuhu; Wang, Lei; Yang, Dian

    2017-12-01

    This article demonstrated a technology for producing high purity hexachlorodisilane what is one raw material of Semiconductor industry, which using the method of combination adsorption with rectification, whose material was from polysilicon residues of polysilicon company. This technology could remove most high boiling points chloro-silicane impurities and metal impurities effectively. The purity of Si2Cl6 produced by this technology can be up to 99.9%, the content of metal impurities can be low at 4ppb, which can meet the requirement of industy using completely. The technology extends the routes of Si2Cl6 in localization, having the advantages of simple process, continuous operation, and large capacity and so on.

  10. High purity hydrogen generator for on-site hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Jaesung Han; Il-Su Kim; Keun-Seob Choi [Taedok Institute of Technology, Taejon (Korea)

    2002-10-01

    We report a compact on-site hydrogen generator, which produces 10 Nm{sup 3}/h of 99.9995% or higher purity hydrogen from methanol water mixture. This system consists of a methanol steam reformer to get hydrogen rich reformed gas and a metal membrane purification module to recover high purity hydrogen from the reformed gas. It can be used either as the on-site hydrogen supplier for industries or as the fuel processor for fuel cells. The hydrogen recovery by the metal membrane is about 75%, and the remaining 25% of hydrogen is recycled and burned in the catalytic combustion zone to supply heat for the endothermic steam reforming reaction. The overall thermal efficiency of the system is calculated to be 82% based on high heating values of methanol feed and product hydrogen. (author)

  11. High purity zirconium obtainment through the iodine compounds transport method

    International Nuclear Information System (INIS)

    Bolcich, J.C.; Zuzek, E.; Dutrus, S.M.; Corso, H.L.

    1987-01-01

    This paper describes the experimental method and the equipment designed, constructed and actually applied for the high purity zirconium obtainment from a zirconium sponge of the nuclear type. The mechanism of purification is based on the impure metal attack with gaseous iodine (at 200 deg C) to obtain zirconium tetra iodine as main product which is then transformed into a pure zirconium base (at 1000-1300 deg C), precipitating the metallic zirconium and releasing the gaseous iodine. From the first experiences carried out, pure zirconium has been obtained from an initial filament of 0.5 mm of diameter as well as wires up to 2.5 mm of diameter. This work presents the results from the studies and analysis made to characterize the material obtained. Finally, the refining methods to which the zirconium produced may be submitted so as to optimize the final purity are discussed. (Author)

  12. Synthesis of High Purity Nonsymmetric Dialkylphosphinic Acid Extractants.

    Science.gov (United States)

    Wang, Junlian; Xie, Meiying; Liu, Xinyu; Xu, Shengming

    2017-10-19

    We present the synthesis of (2,3-dimethylbutyl)(2,4,4'-trimethylpentyl)phosphinic acid as an example to demonstrate a method for the synthesis of high purity nonsymmetric dialkylphosphinic acid extractants. Low toxic sodium hypophosphite was chosen as the phosphorus source to react with olefin A (2,3-dimethyl-1-butene) to generate a monoalkylphosphinic acid intermediate. Amantadine was adopted to remove the dialkylphosphinic acid byproduct, as only the monoalkylphosphinic acid can react with amantadine to form an amantadine∙mono-alkylphosphinic acid salt, while the dialkylphosphinic acid cannot react with amantadine due to its large steric hindrance. The purified monoalkylphosphinic acid was then reacted with olefin B (diisobutylene) to yield nonsymmetric dialkylphosphinic acid (NSDAPA). The unreacted monoalkylphosphinic acid can be easily removed by a simple base-acid post-treatment and other organic impurities can be separated out through the precipitation of the cobalt salt. The structure of the (2,3-dimethylbutyl)(2,4,4'-trimethylpentyl)phosphinic acid was confirmed by 31 P NMR, 1 H NMR, ESI-MS, and FT-IR. The purity was determined by a potentiometric titration method, and the results indicate that the purity can exceed 96%.

  13. Spectroscopic Determination of Trace Contaminants in High Purity Oxygen

    Science.gov (United States)

    Hornung, Steven D.

    2011-01-01

    Oxygen used for extravehicular activities (EVA) must be free of contaminants because a difference in a few tenths of a percent of argon or nitrogen content can mean significant reduction in available EVA time. These inert gases build up in the extravehicular mobility unit because they are not metabolized or scrubbed from the atmosphere. Measurement of oxygen purity above 99.5% is problematic, and currently only complex instruments such as gas chromatographs or mass spectrometers are used for these determinations. Because liquid oxygen boil-off from the space shuttle will no longer be available to supply oxygen for EVA use, other concepts are being developed to produce and validate high purity oxygen from cabin air aboard the International Space Station. A prototype optical emission technique capable of detecting argon and nitrogen below 0.1% in oxygen was developed at White Sands Test Facility. This instrument uses a glow discharge in reduced pressure gas to produce atomic emission from the species present. Because the atomic emission lines from oxygen, nitrogen, and argon are discrete and in many cases well-separated, trace amounts of argon and nitrogen can be detected in the ultraviolet and visible spectrum. This is a straightforward, direct measurement of the target contaminants and may lend itself to a device capable of on-orbit verification of oxygen purity. System design and optimized measurement parameters are presented.

  14. Process for the production of high purity deuterium

    International Nuclear Information System (INIS)

    Arrathoon, R.

    1977-01-01

    A process for the electrolysis of heavy water which results in the production of high purity deuterium without periodic replenishment of the electrolyte with additional deuterated compounds is defined. Electrolysis is effected through the use of an inexpensive cation-action permselective membrane which is essentially a solid polymer electrolyte and which is capable of automatically separating the evolved deuterium and oxygen gas. This cation-active permselective membrane does not introduce any intrinsic impurities or tritium contamination in the generated deuterium gas, does not require periodic revitalization with deuterated compounds or other chemical compounds, and is characterized by an unusually high electrical efficiency

  15. Electrochemical Deposition of High Purity Silicon from Molten Salts

    Science.gov (United States)

    Haarberg, Geir Martin

    Several approaches were tried in order to develop an electrochemical route for producing high purity silicon from molten salts. SiO2, K2SiF6 and metallurgical silicon were used as the source of silicon. Molten electrolytes based on chloride (CaCl2-NaCl) and fluoride (LiF-KF) at temperatures from 550 - 900 oC were used. Transient electrochemical techniques were used to study the electrochemical behaviour of dissolved silicon species. Electrolysis experiments were carried out to deposit silicon.

  16. Electrochemical Deposition of High Purity Silicon in Molten Salts

    Science.gov (United States)

    Haarberg, Geir Martin

    Several approaches were tried in order to develop an electrochemical route for producing high purity silicon from molten salts. SiO2, K2SiF6 and metallurgical silicon were used as the source of silicon. Molten electrolytes based on chloride (CaCl2-NaCl) and fluoride (LiF-KF) at temperatures from 550 - 900 °C were used. Transient electrochemical techniques were used to study the electrochemical behaviour of dissolved silicon species. Electrolysis experiments were carried out to deposit silicon.

  17. Amplitude dependent damping in single crystalline high purity molybdenum

    International Nuclear Information System (INIS)

    Zelada-Lambri, G.I; Lambri, O.A; Garcia, J.A; Lomer, J.N

    2004-01-01

    Amplitude dependent damping measurements were performed on high purity single crystalline molybdenum at several different constant temperatures between room temperature and 1273K. The employed samples were single crystals with the orientation, having a residual resistivity ratio of about 8000. Previously to the amplitude dependent damping tests, the samples were subjected to different thermomechanical histories. Amplitude dependent damping effects appear only during the first heating run in temperature where the samples have the thermomechanical state of the deformation process at room temperature. In the subsequent run-ups in temperature, i.e, after subsequent annealings, amplitude dependent damping effects were not detected (au)

  18. The ion-exchange obtaining of high purity samarium oxide

    International Nuclear Information System (INIS)

    Brzyska, W.; Soltysiak, I.; Cygan, J.

    1987-01-01

    The use of lactic acid - EDTA mixture as an eluent for the obtaining of high purity samarium oxide was studied. The studies were carried out at room temperature on cation exchange resin Wofatit KPS X 8. The best results were obtained for lactic acid (0,26 mol/dm 3 ) - EDTA (0,013 mol/dm 3 ) mixture at pH 3,3. As the result of 57% samarium concentrate elution with column load 1:3 and flow rate 0,4 cm/min, over 99% pure samarium oxide with 73% yield has been obtained. The yield of spectrally pure Sm 2 O 3 exceeded 45%. (author)

  19. High purity neodymium acetate from mixed rare earth carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Carlos A. da Silva; Rocha, Soraya M. Rizzo da; Vasconcellos, Mari E. de; Lobo, Raquel M.; Seneda, Jose A., E-mail: cqueiroz@ipen.b, E-mail: smrrocha@ipen.b, E-mail: mstela@ipen.b, E-mail: rmlobo@ipen.b, E-mail: jaseneda@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Pedreira, Walter dos R., E-mail: walter.pedreira@fundacentro.gov.b [Fundacao Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho (FUNDACENTRO), Sao Paulo, SP (Brazil)

    2011-07-01

    A simple and economical chemical process for obtaining high purity neodymium acetate is discussed. The raw material in the form rare earth carbonate is produced industrially from the chemical treatment of Brazilian monazite. Ion exchange chromatography technique with a strong cationic resin, proper to water treatment, and without the use of retention ions was used for the fractionating of the rare earth elements (REE). In this way, it was possible to obtain 99.9% pure Nd{sub 2}O{sub 3} in yields greater than or equal 80%, with the elution of the REE using ammonium salt of ethylenediaminetetraacetic acid (EDTA) solution in pH controlled. The complex of EDTA-neodymium was transformed into neodymium oxide, which was subsequently dissolved in acetic acid to obtain the neodymium acetates. Molecular absorption spectrophotometry was used to monitor the neodymium content during the process and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the neodymium acetates. The typical neodymium acetates obtained contain the followings contaminants in {mu}g g{sup -1}: Sc(5.1); Y (0.9); La (1.0); Ce (6.1); Pr (34,4); Sm (12.8); Eu (1.1); Gd (15.4); Tb (29.3); Dy (5.2), Ho(7.4); Er (14.6); Tm (0.3); Yb (2.5); Lu (1.0). The high purity neodymium acetates obtained from this procedure have been applied, replacing the imported product, in research and development area on rare earth catalysts. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Abdo, Gustavo Giovanni Ribeiro, E-mail: Gustavo.abdo@cbmm.com.br; Sousa, Clovis Antonio de Faria, E-mail: Clovis@cbmm.com.br; Guimarães, Rogério Contato, E-mail: Rogerio.guimaraes@cbmm.com.br; Ribas, Rogério Marques, E-mail: Rogerio.ribas@cbmm.com.br; Vieira, Alaércio Salvador Martins, E-mail: Alaercio.vieira@cbmm.com.b; Menezes, Andréia Duarte, E-mail: Amenezes@cbmm.com.br; Fridman, Daniel Pallos, E-mail: Daniel.fridman@cbmm.com.br; Cruz, Edmundo Burgos, E-mail: Edmundo@cbmm.com.br [CBMM – Companhia Brasileira de Metalurgia e Mineração Córrego da Mata, s/n Araxá, Minas Gerais 38183-903 Brazil (Brazil)

    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.

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

    International Nuclear Information System (INIS)

    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

    2015-01-01

    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

  2. High purity samarium oxide from mixed rare earth carbonates

    International Nuclear Information System (INIS)

    Queiroz, Carlos A. da S.; Seneda, Jose A.; Vasconcellos, Mari E. de; Pedreira Filho, Walter dos R.

    2013-01-01

    A simple and economical chemical process for the production of highly pure samarium oxides is discussed. The raw material, which was used in the form of rare earth carbonates was produced industrially from the chemical treatment of Brazilian monazite. Ion exchange chromatography was performed using a strong cationic resin that is typically employed in water treatment processes to fractionate rare earth elements (REE) without the use of retention ions. Under these conditions, 99.9% pure Sm 2 O 3 was eluted using the ammonium salt of ethylenediaminetetraacetic acid (EDTA) at a controlled pH. The EDTA-samarium complex was separated from EDTA and then precipitated as oxalate and fired to samarium oxide. Molecular absorption spectrophotometry was used to monitor the samarium content during the proposed process, and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the samarium oxide. Typical samarium oxide obtained from the proposed procedure contained the following contaminants in micrograms per gram: Sc (20.90); Y (11.80); La (8.4); Ce (4.3); Pr (2.5); Nd (5.1); Eu (94); Gd (114); Tb (3.6); Dy (2.5), Ho (2.3); Er (3.0); Tm (2.3); Yb (38,2); Lu (25.6). The high-purity samarium oxides produced in the present study can be used as an alternative to imported products in research and development applications. (author)

  3. Evaluation of purity with its uncertainty value in high purity lead stick by conventional and electro-gravimetric methods.

    Science.gov (United States)

    Singh, Nahar; Singh, Niranjan; Tripathy, S Swarupa; Soni, Daya; Singh, Khem; Gupta, Prabhat K

    2013-06-26

    A conventional gravimetry and electro-gravimetry study has been carried out for the precise and accurate purity determination of lead (Pb) in high purity lead stick and for preparation of reference standard. Reference materials are standards containing a known amount of an analyte and provide a reference value to determine unknown concentrations or to calibrate analytical instruments. A stock solution of approximate 2 kg has been prepared after dissolving approximate 2 g of Pb stick in 5% ultra pure nitric acid. From the stock solution five replicates of approximate 50 g have been taken for determination of purity by each method. The Pb has been determined as PbSO4 by conventional gravimetry, as PbO2 by electro gravimetry. The percentage purity of the metallic Pb was calculated accordingly from PbSO4 and PbO2. On the basis of experimental observations it has been concluded that by conventional gravimetry and electro-gravimetry the purity of Pb was found to be 99.98 ± 0.24 and 99.97 ± 0.27 g/100 g and on the basis of Pb purity the concentration of reference standard solutions were found to be 1000.88 ± 2.44 and 1000.81 ± 2.68 mg kg-1 respectively with 95% confidence level (k = 2). The uncertainty evaluation has also been carried out in Pb determination following EURACHEM/GUM guidelines. The final analytical results quantifying uncertainty fulfills this requirement and gives a measure of the confidence level of the concerned laboratory. Gravimetry is the most reliable technique in comparison to titremetry and instrumental method and the results of gravimetry are directly traceable to SI unit. Gravimetric analysis, if methods are followed carefully, provides for exceedingly precise analysis. In classical gravimetry the major uncertainties are due to repeatability but in electro-gravimetry several other factors also affect the final results.

  4. Portable High Sensitivity and High Resolution Sensor to Determine Oxygen Purity Levels, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this Phase I STTR project is to develop a highly sensitive oxygen (O2) sensor, with high accuracy and precision, to determine purity levels of high...

  5. The production of high-purity aluminum in Japan

    Science.gov (United States)

    Kondo, Mitsuhiro; Maeda, Hideo; Mizuguchi, Mikio

    1990-11-01

    The two most widely industrialized techniques for aluminum refining are the three-layer electrolytic refining process and the segregation process. The three-layer process uses molten salt electrolysis to produce aluminum of greater than 99.99% purity. The segregation process produces aluminum of 99.98-99.99% purity. Although aluminum refined by the segregation process has a somewhat lower purity than that produced by the other methods, the segregation process has become increasing common since it consumes less energy. Ultrahigh-purity aluminum (99.9999%), which has uranium and thorium impurities reduced to less than 1 ppb, can also be produced.

  6. Investigation of sulphides in iron alloys of high purity

    International Nuclear Information System (INIS)

    Wyjadlowski, T.

    1973-01-01

    This research thesis reports the study of the morphology and composition of sulphides in iron alloys with respect to metal composition and to the nature of impurities. In order to understand the specific action of each addition on inclusion morphology, this work has started with high-purity alloys (binary alloys and then ternary alloys). The author studied whether solubility variations would entail either intergranular or intragranular or hybrid iron sulphide precipitation. He examined whether sulphide morphology is depending on thermal treatment, and whether equilibrium precipitates were different in terms of morphology and composition at high and room temperature. He studied the influence of addition elements on sulphide morphology and composition, an important issue as some elements may reduce brittleness. These elements are classified in terms of affinity with sulphur

  7. Preparation of high purity yttrium single crystals by electrotransport

    International Nuclear Information System (INIS)

    Volkov, V.T.; Nikiforova, T.V.; Ionov, A.M.; Pustovit, A.N.; Sikharulidse, G.G.

    1981-01-01

    The possibility of obtaining yttrium crystals of high purity by the method of solid state electrotransport (SSE) was investigated in the present work. The behaviour of low contents of iron, aluminium, silicon, tantalum, copper, silver and vanadium as metallic impurities was studied using mass spectrometry. It is shown that all the impurities investigated, except copper, migrate to the anode. During electrotransfer a purification with respect to these impurities by a factor of 4 - 6 is obtained. It is proposed that the diffusion coefficients of the metallic impurities investigated are anomalously high and that the behaviour of the impurities during SSE in adapters necessitates further investigation. By using a three-stage process with intermediate removal of the anode end yttrium single crystals with a resistance ratio rho 293 /rhosub(4.2)=570 were produced. (Auth.)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Purity analyses of high-purity organic compounds with nitroxyl radicals based on the Curie-Weiss law

    Science.gov (United States)

    Matsumoto, Nobuhiro; Shimosaka, Takuya

    2015-05-01

    This work reports an attempt to quantify the purities of powders of high-purity organic compounds with stable nitroxyl radicals (namely, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO), 1-oxyl-2,2,6,6-tetramethyl-4-hydroxypiperidine (TEMPOL), and 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl benzoate (4-hydroxy-TEMPO benzoate)) in terms of mass fractions by using our "effective magnetic moment method," which is based on both the Curie-Weiss law and a fundamental equation of electron paramagnetic resonance (ESR). The temperature dependence of the magnetic moment resulting from the radicals was measured with a superconducting quantum interference device magnetometer. The g value for each compound was measured with an X-band ESR spectrometer. The results of the purities were (0.998 ± 0.064) kg kg-1 for TEMPO, (1.019 ± 0.040) kg kg-1 for TEMPOL, and (1.001 ± 0.048) kg kg-1 for 4-hydroxy-TEMPO benzoate. These results demonstrate that this analytical method as a future candidate of potential primary direct method can measure the purities with expanded uncertainties of approximately 5%.

  10. Purity analyses of high-purity organic compounds with nitroxyl radicals based on the Curie–Weiss law

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Nobuhiro, E-mail: nobu-matsumoto@aist.go.jp; Shimosaka, Takuya [National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), AIST Central-3, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563 (Japan)

    2015-05-07

    This work reports an attempt to quantify the purities of powders of high-purity organic compounds with stable nitroxyl radicals (namely, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO), 1-oxyl-2,2,6,6-tetramethyl-4-hydroxypiperidine (TEMPOL), and 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl benzoate (4-hydroxy-TEMPO benzoate)) in terms of mass fractions by using our “effective magnetic moment method,” which is based on both the Curie–Weiss law and a fundamental equation of electron paramagnetic resonance (ESR). The temperature dependence of the magnetic moment resulting from the radicals was measured with a superconducting quantum interference device magnetometer. The g value for each compound was measured with an X-band ESR spectrometer. The results of the purities were (0.998 ± 0.064) kg kg{sup −1} for TEMPO, (1.019 ± 0.040) kg kg{sup −1} for TEMPOL, and (1.001 ± 0.048) kg kg{sup −1} for 4-hydroxy-TEMPO benzoate. These results demonstrate that this analytical method as a future candidate of potential primary direct method can measure the purities with expanded uncertainties of approximately 5%.

  11. Electron beam welding of high-purity copper accelerator cells

    International Nuclear Information System (INIS)

    Delis, K.; Haas, H.; Schlebusch, P.; Sigismund, E.

    1986-01-01

    The operating conditions of accelerator cells require high thermal conductivity, low gas release in the ultrahigh vacuum, low content of low-melting metals and an extremely good surface quality. In order to meet these requirements, high-purity copper (OFHC, Grade 1, according to ASTM B 170-82 and extra specifications) is used as structural material. The prefabricated components of the accelerator cells (noses, jackets, flanges) are joined by electron beam welding, the weld seam being assessed on the basis of the same criteria as the base material. The welding procedures required depend, first, on the material and, secondly, on the geometries involved. Therefore experimental welds were made first on standardized specimens in order to study the behaviour of the material during electron beam welding and the influence of parameter variations. The welded joints of the cell design were planned on the basis of these results. Seam configuration, welding procedures and the parameters were optimized on components of original geometry. The experiments have shown that high-quality joints of this grade of copper can be produced by the electron beam welding process, if careful planning and preparation of the seams and adequate containment of the welding pool are assured. (orig.)

  12. Stress Corrosion Cracking Sensitivity of High Purity Fe-Cr Alloys in High Temperature Water

    OpenAIRE

    Takaku, H.; Kato, S.; Tani, J.; Abiko, K.

    1995-01-01

    Stress Corrosion Cracking (SCC) sensitivities of high purity Fe-Cr alloys were investigated in simulated Boiling Water Reactor (BWR) and primary Pressurized Water Reactor (PWR) cooling waters, by constant extension rate tests (CERT) at a strain rate of 4x10-7s-1. No high purity Fe-Cr alloy showed any SCC sensitivity in either simulated BWR and PWR primary water environment.

  13. Mesophase Formation Stabilizes High-purity Magic-sized Clusters

    KAUST Repository

    Nevers, Douglas R.

    2018-01-27

    Magic-sized clusters (MSCs) are renowned for their identical size and closed-shell stability that inhibit conventional nanoparticle (NP) growth processes. Though MSCs have been of increasing interest, understanding the reaction pathways toward their nucleation and stabilization is an outstanding issue. In this work, we demonstrate that high concentration synthesis (1000 mM) promotes a well-defined reaction pathway to form high-purity MSCs (>99.9%). The MSCs are resistant to typical growth and dissolution processes. Based on insights from in-situ X-ray scattering analysis, we attribute this stability to the accompanying production of a large, hexagonal organic-inorganic mesophase (>100 nm grain size) that arrests growth of the MSCs and prevents NP growth. At intermediate concentrations (500 mM), the MSC mesophase forms, but is unstable, resulting in NP growth at the expense of the assemblies. These results provide an alternate explanation for the high stability of MSCs. Whereas the conventional mantra has been that the stability of MSCs derives from the precise arrangement of the inorganic structures (i.e., closed-shell atomic packing), we demonstrate that anisotropic clusters can also be stabilized by self-forming fibrous mesophase assemblies. At lower concentration (<200 mM or >16 acid-to-metal), MSCs are further destabilized and NPs formation dominates that of MSCs. Overall, the high concentration approach intensifies and showcases inherent concentration-dependent surfactant phase behavior that is not accessible in conventional (i.e., dilute) conditions. This work provides not only a robust method to synthesize, stabilize, and study identical MSC products, but also uncovers an underappreciated stabilizing interaction between surfactants and clusters.

  14. High-purity, robust alkali vapor sources without vacuum feedthroughs

    Science.gov (United States)

    Kohn, Rudolph; Bigelow, Matthew; Imhof, Eric; Squires, Matthew; Olson, Spencer; Kasch, Brian; Hostutler, David

    2017-04-01

    The authors report the successful implementation of a method for producing rubidium vapor at sufficient purity and with sufficient quantity to load cold atom experiments. This method requires no vacuum feedthroughs and has measurable advantages in several parameters over commercial chromate dispensers, including vapor purity, required heating power, and capacity per unit volume. It is reasonably stable when exposed to air, allowing for easy handling. Currently, this method is being integrated into the authors' systems and its use in loading a basic 3D vapor cell magneto-optical trap (MOT) has been demonstrated, in addition to loading a 2D+ MOT which has been subsequently used to load a 3D MOT.

  15. Analytical monitoring of systems for the production of high-purity, desalinated water

    International Nuclear Information System (INIS)

    Kunert, I.

    1988-01-01

    The purity requirements to be met by high-purity water currently push the most sensitive analytical methods to their utmost limits of sensitivity. The required degree of purity of the water at present can only be achieved by application of membrane processes, and pre-purification of the feedwater to a quality corresponding to that of the raw water source. The contribution in hand discusses the analytical monitoring of the raw water treatment plant, the water treatment prior to the treatment by reverse osmosis, monitoring and control of the modules for reverse osmosis, and the monitoring of high-purity water production for the microelectronics industry. (orig./RB) [de

  16. Method for the production of high-purity triaminotrinitrobenzene

    Science.gov (United States)

    Benziger, Theodore M.

    1977-01-01

    Triaminotrinitrobenzene is readily formed by the nitration of 1,3,5-trichlorobenzene to 1,3,5-trichloro-2,4,6-trinitrobenzene followed by amination to triaminotrinitrobenzene. The purity of the triaminotrinitrobenzene is significantly improved if, during the amination step, sufficient water is present that the byproduct ammonium chloride formed during the amination is rendered at least semideliquescent.

  17. State-of-the-art in analytical characterization of high purity solid ...

    Indian Academy of Sciences (India)

    Unknown

    State-of-the-art in analytical characterization of high purity solid samples by different spectroscopic methods. S S GRAZHULENE. Institute of Microelectronics Technology and High Purity Materials, RAS 142432, Chernogolovka, Russia. Abstract. Facilities and some results of several spectroscopic methods which have ...

  18. A light hydrocarbon fuel processor producing high-purity hydrogen

    Science.gov (United States)

    Löffler, Daniel G.; Taylor, Kyle; Mason, Dylan

    This paper discusses the design process and presents performance data for a dual fuel (natural gas and LPG) fuel processor for PEM fuel cells delivering between 2 and 8 kW electric power in stationary applications. The fuel processor resulted from a series of design compromises made to address different design constraints. First, the product quality was selected; then, the unit operations needed to achieve that product quality were chosen from the pool of available technologies. Next, the specific equipment needed for each unit operation was selected. Finally, the unit operations were thermally integrated to achieve high thermal efficiency. Early in the design process, it was decided that the fuel processor would deliver high-purity hydrogen. Hydrogen can be separated from other gases by pressure-driven processes based on either selective adsorption or permeation. The pressure requirement made steam reforming (SR) the preferred reforming technology because it does not require compression of combustion air; therefore, steam reforming is more efficient in a high-pressure fuel processor than alternative technologies like autothermal reforming (ATR) or partial oxidation (POX), where the combustion occurs at the pressure of the process stream. A low-temperature pre-reformer reactor is needed upstream of a steam reformer to suppress coke formation; yet, low temperatures facilitate the formation of metal sulfides that deactivate the catalyst. For this reason, a desulfurization unit is needed upstream of the pre-reformer. Hydrogen separation was implemented using a palladium alloy membrane. Packed beds were chosen for the pre-reformer and reformer reactors primarily because of their low cost, relatively simple operation and low maintenance. Commercial, off-the-shelf balance of plant (BOP) components (pumps, valves, and heat exchangers) were used to integrate the unit operations. The fuel processor delivers up to 100 slm hydrogen >99.9% pure with <1 ppm CO, <3 ppm CO 2. The

  19. The Hydrometallurgical Extraction and Recovery of High-Purity Silver

    Science.gov (United States)

    Hoffmann, James E.

    2012-06-01

    -bearing inputs, will be described in detail to demonstrate how typical chemical engineering unit process and unit operations have supplanted classic smelting and fire refining techniques. The Kennecott Copper Company, which has operated a hydrometallurgical circuit successfully for the recovery of high-purity silver from the slimes wet chlorination residue, has permitted me to provide some operation information and results using the technology. Both Phelps Dodge and Kennecott should be recognized for their forward-looking attitude in undertaking the conversion of conceptual chemistry into successful, full-scale plants. The process as employed at Phelps Dodge is discussed at length in reference (J.E. Hoffmann and B. Wesstrom: Hydrometallurgy, 1994, vol. 94, pp. 69-105).

  20. Corrosion of high purity Fe-Cr-Ni alloys in 13 N boiling nitric acid

    International Nuclear Information System (INIS)

    Ohta, Joji; Mayuzumi, Masami; Kusanagi, Hideo; Takaku, Hiroshi

    1998-01-01

    Corrosion in boiling nitric acid was investigated for high purity Fe-18%Cr-12%Ni alloys and type 304L stainless steels (SS). Owing to very low impurity concentration, the solution treated high purity alloys show almost no intergranular corrosion while the type 304L SS show severe intergranular corrosion. Both in the high purity alloys and type 304L SS, aging treatments ranging from 873 K to 1073 K for 1 h enhance intergranular corrosion. During the aging treatments, impurities should be segregated to the grain boundaries. The corrosion behaviors were discussed from a standpoint of impurity segregation to grain boundaries. This study is of importance for purex reprocessing of spent fuels

  1. Deformation behaviour of fine grained high purity beryllium - influence of fabrication parameters, temperature and copper additions

    International Nuclear Information System (INIS)

    Kaltenbach, K.

    1982-01-01

    The deformation behaviour of high-purity beryllium was tested on hot isostatically pressed samples of different initial grain size and compared with material manufactured commercially from pure beryllium and with beryllium-copper alloys containing 0.44, 1.1 and 2.1 at.% copper. Initial grain size of these high purity material was 0 C. Grain structure of the samples was subsequently analysed by light, rastor and transmission electron microscopy. The influence of copper additions on deformation of high-purity beryllium was analysed. A further aim of this study was to investigate, by suitable methods, the mode of action of relevant impurities and to throw light on their influence on grain formation. This should enable reliable information to be provided for the manufacture of high-purity beryllium which, in turn, will lead to an improvement in ductility. (orig./IHOE) [de

  2. Dynamical recrystallization of high purity austenitic stainless steels

    International Nuclear Information System (INIS)

    Gavard, L.

    2001-01-01

    The aim of this work is to optimize the performance of structural materials. The elementary mechanisms (strain hardening and dynamical regeneration, germination and growth of new grains) occurring during the hot working of metals and low pile defect energy alloys have been studied for austenitic stainless steels. In particular, the influence of the main experimental parameters (temperature, deformation velocity, initial grain size, impurities amount, deformation way) on the process of discontinuous dynamical recrystallization has been studied. Alloys with composition equal to those of the industrial stainless steel-304L have been fabricated from ultra-pure iron, chromium and nickel. Tests carried out in hot compression and torsion in order to cover a wide range of deformations, deformation velocities and temperatures for two very different deformation ways have allowed to determine the rheological characteristics (sensitivity to the deformation velocity, apparent activation energy) of materials as well as to characterize their microstructural deformations by optical metallography and electron back-scattered diffraction. The influence of the initial grain size and the influence of the purity of the material on the dynamical recrystallization kinetics have been determined. An analytical model for the determination of the apparent mobility of grain boundaries, a semi-analytical model for the dynamical recrystallization and at last an analytical model for the stationary state of dynamical recrystallization are proposed as well as a new criteria for the transition between the refinement state and the state of grain growth. (O.M.)

  3. Spectroscopic Determination of Trace Contaminants in High-Purity Oxygen

    Science.gov (United States)

    Hornung, Steven

    2013-01-01

    Oxygen used for extravehicular activities (EVAs) must be free of contaminants because a difference in a few tenths of a percent of argon or nitrogen content can mean significant reduction in available EVA time. These inert gases build up in the extravehicular mobility unit because they are not metabolized or scrubbed from the atmosphere. A prototype optical emission technique capable of detecting argon and nitrogen below 0.1% in oxygen has been developed. This instrument uses a glow discharge in reduced-pressure gas to produce atomic emission from the species present. Because the atomic emission lines from oxygen, nitrogen, and argon are discrete, and in many cases well-separated, trace amounts of argon and nitrogen can be detected in the ultraviolet and visible spectrum. This is a straightforward, direct measurement of the target contaminants, and may lend itself to a device capable of on-orbit verification of oxygen purity. A glow discharge is a plasma formed in a low-pressure (1 to 10 Torr) gas cell between two electrodes. Depending on the configuration, voltages ranging from 200 V and above are required to sustain the discharge. In the discharge region, the gas is ionized and a certain population is in the excited state. Light is produced by the transitions from the excited states formed in the plasma to the ground state. The spectrum consists of discrete, narrow emission lines for the atomic species, and broader peaks that may appear as a manifold for molecular species such as O2 and N2, the wavelengths and intensities of which are a characteristic of each atom. The oxygen emission is dominated by two peaks at 777 and 844 nm.

  4. Radiochemical purity of Mo and Tc solution obtained after irradiation and dissolution of Mo-100-enriched and ultra-high-purity natural Mo disks

    Energy Technology Data Exchange (ETDEWEB)

    Tkac, Peter [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States); Chemerisov, Sergey D. [Argonne National Lab. (ANL), Argonne, IL (United States); Rotsch, David A. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-09-01

    Four irradiations of ultra-high-purity natural Mo targets and one irradiation using 97.4% Mo-100-enriched material were performed. The purpose of these irradiations was to determine whether the presence of Sn stabilizer in the H2O2 used for the dissolution of sintered Mo disks can affect the radiochemical purity of the final K2MoO4 in 5M KOH solution. Results from radiochemical purity tests performed using thin-layer paper chromatography show that even 2– 3× excess of Sn-stabilized H2O2 typically used for dissolution of sintered Mo disks did not affect the radiochemical purity of the final product.

  5. Producing High Priests and Princesses: The Father-Daughter Relationship in the Christian Sexual Purity Movement

    Directory of Open Access Journals (Sweden)

    Elizabeth Gish

    2016-03-01

    Full Text Available This article describes and analyzes father-daughter purity balls in the context of the contemporary U.S. American conservative Christian sexual purity movement, with an emphasis on taking the self-understanding of those involved in the movement into account. It shows the ways that the idealization of a hierarchical father-daughter relationship both constructs and reflects sexual purity ideals. The Christian sexual purity teachings frame this father-daughter relationship as an essential part of forming the ideal subject, and as reflective of the right order of the kingdom of God. In the logic of sexual purity, a good man is the strong high-priest leader of the household and the ideal girl is princess-like: white, non-poor, attractive, pure, feminine, delicate, and receptive. She is preparing, under her father’s guidance, for heterosexual marriage. Attention to the father-daughter relationship in the sexual purity movement highlights the ways that sexual purity is primarily about subject formation and the ordering of relationships—in families, in the nation, and in the church—and less about the specifics of when particular sexual acts take place or the public health risks that might come from those acts. This exploration also brings into relief the ways that contemporary conservative Christian sexual purity teachings draw from and build on two prominent aspects of contemporary U.S. American popular culture: the important role of the princess figure, and the buying of goods as indispensable to the formation of the subject.

  6. Establishing comparability and compatibility in the purity assessment of high purity zinc as demonstrated by the CCQM-P149 intercomparison

    Science.gov (United States)

    Vogl, Jochen; Kipphardt, Heinrich; Richter, Silke; Bremser, Wolfram; del Rocío Arvizu Torres, María; Manzano, Judith Velina Lara; Buzoianu, Mirella; Hill, Sarah; Petrov, Panayot; Goenaga-Infante, Heidi; Sargent, Mike; Fisicaro, Paola; Labarraque, Guillaume; Zhou, Tao; Turk, Gregory C.; Winchester, Michael; Miura, Tsutomu; Methven, Brad; Sturgeon, Ralph; Jährling, Reinhard; Rienitz, Olaf; Mariassy, Michal; Hankova, Zuzana; Sobina, Egor; Ivanovich Krylov, Anatoly; Anatolievich Kustikov, Yuri; Vladimirovich Smirnov, Vadim

    2018-04-01

    For the first time, an international comparison was conducted on the determination of the purity of a high purity element. Participants were free to choose any analytical approach appropriate for their institute’s applications and services. The material tested was a high purity zinc, which had earlier been assessed for homogeneity and previously used in CCQM-K72 for the determination of six defined metallic impurities. Either a direct metal assay of the Zn mass fraction was undertaken by EDTA titrimetry, or an indirect approach was used wherein all impurities, or at least the major ones, were determined and their sum subtracted from ideal purity of 100%, or 1 kg kg-1. Impurity assessment techniques included glow discharge mass spectrometry, inductively coupled plasma mass spectrometry and carrier gas hot extraction/combustion analysis. Up to 91 elemental impurities covering metals, non-metals and semi-metals/metalloids were quantified. Due to the lack of internal experience or experimental capabilities, some participants contracted external laboratories for specific analytical tasks, mainly for the analysis of non-metals. The reported purity, expressed as zinc mass fraction in the high purity zinc material, showed excellent agreement for all participants, with a relative standard deviation of 0.011%. The calculated reference value, w(Zn)  =  0.999 873 kg kg-1, was assigned an asymmetric combined uncertainty of  +0.000 025 kg kg-1 and  -0.000 028 kg kg-1. Comparability amongst participating metrology institutes is thus demonstrated for the purity determination of high purity metals which have no particular difficulties with their decomposition/dissolution process when solution-based analytical methods are used, or which do not have specific difficulties when direct analysis approaches are used. Nevertheless, further development is required in terms of uncertainty assessment, quantification of non-metals and the determination of purity

  7. [Simultaneously preparation of grams of high purity tyrosol, crenulatin and salidroside from Rhodiola crenulata].

    Science.gov (United States)

    Luo, Xin; Wang, Xue-jing; Li, Shi-ping; Zhang, Qiao; Zhao, Yi-wu; Huang Wen-zhe; Wang, Zhen-zhong; Xiao, Wei

    2015-04-01

    Tyrosol, crenulatin and salidroside are the main active constituents of Rhodiola crenulata, with extensive pharmacological activities. In the study, grams of high purity tyrosol, crenulatin and salidroside were simultaneously separated from R. crenulata by the first time. Firstly, R. crenulata was extracted by 70% alcohol. Then, with the yields of three compounds as the index, the macroporous resin was optimized. At last, grams of high purity tyrosol, crenulatin and salidroside were isolated by D-101 macroporousresin, purified by column chromatography. Detected by HPLC, the purity of three compounds were higher than 98%. This method has the advantages of simple process and operation, less dosage of organic solvent, highly yield and reproducibility, suitable for the simultaneously preparation of tyrosol, crenulatin and salidroside.

  8. Plasma Spray Synthesis of High Purity Boron Nitride Nanotubes

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this project is the efficient synthesis of high quality boron nitride nanotubes (BNNT’s) using the LaRC radio frequency plasma spray (RFPS)...

  9. Growth of high purity semiconductor epitaxial layers by liquid phase ...

    Indian Academy of Sciences (India)

    Unknown

    operation of these devices strongly depend on the quality of the epitaxial layers. The growth system must be able to grow materials with very low unintentional impurity den- sity, high mobility and good luminescence properties. We have used LPE technique to perfect the growth of a num- ber of group III–V epitaxial materials ...

  10. Non-iridescent transmissive structural color filter featuring highly efficient transmission and high excitation purity.

    Science.gov (United States)

    Shrestha, Vivek Raj; Lee, Sang-Shin; Kim, Eun-Soo; Choi, Duk-Yong

    2014-05-12

    Nanostructure based color filtering has been considered an attractive replacement for current colorant pigmentation in the display technologies, in view of its increased efficiencies, ease of fabrication and eco-friendliness. For such structural filtering, iridescence relevant to its angular dependency, which poses a detrimental barrier to the practical development of high performance display and sensing devices, should be mitigated. We report on a non-iridescent transmissive structural color filter, fabricated in a large area of 76.2 × 25.4 mm(2), taking advantage of a stack of three etalon resonators in dielectric films based on a high-index cavity in amorphous silicon. The proposed filter features a high transmission above 80%, a high excitation purity of 0.93 and non-iridescence over a range of 160°, exhibiting no significant change in the center wavelength, dominant wavelength and excitation purity, which implies no change in hue and saturation of the output color. The proposed structure may find its potential applications to large-scale display and imaging sensor systems.

  11. Characterization of segmented large volume, high purity germanium detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bruyneel, B. [Koeln Univ. (Germany). Inst. fuer Kernphysik

    2006-07-01

    {gamma}-ray tracking in future HPGe arrays like AGATA will rely on pulse shape analysis (PSA) of multiple {gamma}-interactions. For this purpose, a simple and fast procedure was developed which enabled the first full characterization of a segmented large volume HPGe detector. An analytical model for the hole mobility in a Ge crystal lattice was developed to describe the hole drift anisotropy with experimental velocity values along the crystal axis as parameters. The new model is based on the drifted Maxwellian hole distribution in Ge. It is verified by reproducing successfully experimental longitudinal hole anisotropy data. A comparison between electron and hole mobility shows large differences for the longitudinal and tangential velocity anisotropy as a function of the electrical field orientation. Measurements on a 12 fold segmented, n-type, large volume, irregular shaped HPGe detector were performed in order to determine the parameters of anisotropic mobility for electrons and holes as charge carriers created by {gamma}-ray interactions. To characterize the electron mobility the complete outer detector surface was scanned in small steps employing photopeak interactions at 60 keV. A precise measurement of the hole drift anisotropy was performed with 356 keV rays. The drift velocity anisotropy and crystal geometry cause considerable rise time differences in pulse shapes depending on the position of the spatial charge carrier creation. Pulse shapes of direct and transient signals are reproduced by weighting potential calculations with high precision. The measured angular dependence of rise times is caused by the anisotropic mobility, crystal geometry, changing field strength and space charge effects. Preamplified signals were processed employing digital spectroscopy electronics. Response functions, crosstalk contributions and averaging procedures were taken into account implying novel methods due to the segmentation of the Ge-crystal and the digital electronics

  12. Modeling of mode purity in high power gyrotrons

    International Nuclear Information System (INIS)

    Cai, S.Y.; Antonsen, T.M. Jr.; Saraph, G.P.

    1993-01-01

    Spurious mode generation at the same frequency of the operational mode in a high power gyrotron can significantly reduce the power handling capability and the stability of a gyrotron oscillator because these modes are usually not matched at the output window and thus have high absorption and reflection rates. To study the generation of this kind of mode, the authors developed a numerical model based on an existing multimode self-consistent time-dependent computer code. This model includes both TE and TM modes and accounts for mode transformations due to the waveguide inhomogeneity. With this new tool, they study the mode transformation in the gyrotron and the possibility of excitation of parasitic TE and TM modes in the up taper section due to the gyroklystron mechanism. Their preliminary results show moderate excitation of both TE and TM modes at the same frequency as the main operating mode at locations near their cutoff. Details of the model and further simulation results will be presented

  13. 90Y of high purity for medical applications

    International Nuclear Information System (INIS)

    Castillo, A.X.; Alvarez, E.O.; Olive, K.I.

    2001-01-01

    Several 90 Sr/ 90 Y-generator systems have been developed and used to produce 90 Y. The most important parameter of the 90 Y to be assayed is 90 Sr content. In addition, when labelling monoclonal antibodies for therapy trace metal quantities accompanying 90 Y (Fe 3+ , Zn 2+ , Cu 2+ , ZrO 2+ , etc.) are to be kept as low as possible in order to obtain high labelling efficiencies. Generally generators' lifetime is limited due to the 90 Sr breakthrough which increases in eluates as a result of the radiolytic degradation of the resin used as support. In the study a described procedure for 90 Y purification from metal contamination is modified in order to lower the amount of 90 Sr present in eluates from generators. As a result a very low 90 Sr content is always assured ( 90 Sr/ 90 Y -6 ). (author)

  14. Recovery of high purity precious metals from printed circuit boards

    International Nuclear Information System (INIS)

    Park, Young Jun; Fray, Derek J.

    2009-01-01

    Waste printed circuit boards (WPCB) have an inherent value because of the precious metal content. For an effective recycling of WPCB, it is essential to recover the precious metals. This paper reports a promising method to recover the precious metals. Aqua regia was used as a leachant and the ratio between metals and leachant was fixed at 1/20 (g/ml). Silver is relatively stable so the amount of about 98 wt.% of the input was recovered without an additional treatment. Palladium formed a red precipitate during dissolution, which were consisted of Pd(NH 4 ) 2 Cl 6 . The amount precipitated was 93 wt.% of the input palladium. A liquid-liquid extraction with toluene was used to extract gold selectively. Also, dodecanethiol and sodium borohydride solution were added to make gold nanoparticles. Gold of about 97 wt.% of the input was recovered as nanoparticles which was identified with a high-resolution transmission electron microscopy through selected area electron diffraction and nearest-neighbor lattice spacing.

  15. State-of-the-art in analytical characterization of high purity solid ...

    Indian Academy of Sciences (India)

    Facilities and some results of several spectroscopic methods which have potential applications in the field of analysis of solid high purity substances and which have been elaborated in Russia, will be discussed in this paper. Laser nondispersive atomic fluorescence method with glow discharge cathode sputtering atomiser, ...

  16. Scalable preparation of high purity rutin fatty acid esters following enzymatic synthesis

    DEFF Research Database (Denmark)

    Lue, Bena-Marie; Guo, Zheng; Xu, Xuebing

    2010-01-01

    Investigations into expanded uses of modified flavonoids are often limited by the availability of these high purity compounds. As such, a simple, effective and relatively fast method for isolation of gram quantities of both long and medium chain fatty acid esters of rutin following scaled-up bios...

  17. Crystallographic Analysis of Nucleation at Hardness Indentations in High-Purity Aluminum

    DEFF Research Database (Denmark)

    Xu, Chaoling; Zhang, Yubin; Lin, Fengxiang

    2016-01-01

    Nucleation at Vickers hardness indentations has been studied in high-purity aluminum cold-rolled 12 pct. Electron channeling contrast was used to measure the size of the indentations and to detect nuclei, while electron backscattering diffraction was used to determine crystallographic orientation...

  18. Preparation of ultra-high purity CdTe single crystals

    International Nuclear Information System (INIS)

    Wang, J.F.; Song, S.H.; Ishikawa, Y.; Isshiki, M.

    2005-01-01

    High-purity and quality CdTe single crystals are very important for their basic study, as well as practical applications. For this reason, Cd was purified by vacuum distillation (VD) and overlap zone-melting (OZM) method, and Te was purified by normal freezing method. Refined Cd was evaluated by glow discharge mass spectroscopy (GDMS) and residual resistivity ratio (RRR) measurement and Te was evaluated by low-temperature photoluminescence (PL) spectra. Results showed that refined Cd and Te have the purity of 6N-up. Using the refined Cd and Te as starting materials, extremely high-purity CdTe single crystals were prepared by the traditional vertical Bridgman technique. The crystals were characterized by low temperature high-resolution PL spectroscopy. Only a sharp peak at 1.5896 eV was detected in exciton emission region. The full width at half-maximum (FWHM) is less than 0.31 meV. These results indicate that the CdTe crystals are of extremely high-purity and quality

  19. Variation of low temperature internal friction of microplastic deformation of high purity molybdenum single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Pal-Val, P.P. (AN Ukrainskoj SSR, Kharkov. Fiziko-Tekhnicheskij Inst. Nizkikh Temperatur); Kaufmann, H.J. (Akademie der Wissenschaften der DDR, Berlin)

    1984-08-01

    Amplitude and temperature spectra of ultrasound absorption in weakly deformed high purity molybdenum single crystals of different orientations were measured. The results were discussed in terms of parameter changes related to quasiparticle or dislocation oscillations, respectively, dislocation point defect interactions as well as defect generation at microplastic deformation.

  20. A determination of the texture of a directionally solidified sample of high-purity copper

    DEFF Research Database (Denmark)

    Grant, Evan; Juul Jensen, Dorte; Ralph, Brian

    1986-01-01

    A study making a combined use of neutron diffraction and selected-area electron channelling to determine the solidification texture in a high-purity copper sample is described. Good correlation between the techniques is shown with both demonstrating a strong [100] fibre texture in the directionally...

  1. Effect of high-temperature heat treatment duration on the purity and ...

    Indian Academy of Sciences (India)

    The effect of high-temperature heat treatment on purity and structural changes of multiwalled carbon nanotubes (MWCNTs) were studied by subjecting the raw MWCNTs (pristine MWCNTs) to 2600°C for 60 and 120 min. Thermogravimetric analysis (TGA), X-ray diffraction, Raman spectroscopy, transmission electron ...

  2. Synthesis of High-Purity Chemical Library Reveals a Potent Inducer of Oxidative Stress

    OpenAIRE

    Cui, Jiayue; Matsumoto, Kenji; Wang, Cindy Y.; Peter, Marcus E.; Kozmin, Sergey A.

    2010-01-01

    Synthesis of high-purity biogenic heterocyclic library enabled identification of a small molecule, which potently inhibited proliferation of several cancer cell lines and induces rapid oxidative stress. This agent elicited unusual mechanism of cell death induction, which entailed activation of both caspase-dependent and independent pathways.

  3. Fabrication and research of high purity germanium detectors with abrupt and thin diffusion layer

    International Nuclear Information System (INIS)

    Rodriguez Cabal, A. E.; Diaz Garcia, A.

    1997-01-01

    A different high purity germanium detector's fabrication method is described. A very thin diffusion film with an abrupt change of the type of conductivity is obtained. The fine diffusion layer thickness makes possibly their utilization in experimental systems in which all the data are elaborated directly on the computer. (author) [es

  4. Effect of high-temperature heat treatment duration on the purity and ...

    Indian Academy of Sciences (India)

    Abstract. The effect of high-temperature heat treatment on purity and structural changes of multiwalled carbon nanotubes (MWCNTs) were studied by subjecting the raw MWCNTs (pristine MWCNTs) to 2600◦C for 60 and 120 min. Thermogravimetric analysis (TGA), X-ray diffraction, Raman spectroscopy, transmission ...

  5. Plasma effects in three-body recombination of high-Z bare ions with electrons

    International Nuclear Information System (INIS)

    Pajek, M.

    1999-01-01

    The influence of plasma effects on three-body recombination of bare ions with electrons in cold plasma in the electron cooler is discussed in context of recombination ''enhancement'' observed in storage ring experiments. We show that for high-Z bare ions and low electron temperatures and densities the cooler plasma becomes ''nonideal'', leading to the enhancement of the three-body recombination rates. This effect is described in terms of the Debye screening length within the ''rigid shift'' approximation. We demonstrate, that in cold (T∼1-10 K) anisotropic plasma the screening effect substantially enhances the three-body recombination rates for very high n-states. The relaxation of high Rydberg states below the field ionization cut-off, set in storage ring experiments, is discussed. The calculations are confronted with the experimental results obtained in storage ring experiments. (orig.)

  6. Low-temperature fracture of high purity iron and its relationship to the grain boundary character

    Energy Technology Data Exchange (ETDEWEB)

    Ofuji, T. (Tohoku Univ., Sendai (Japan). Graduate School of Engineering Daido Special Steel Co. Ltd., Nagoya (Japan)); Suzuki, S. (Tohoku Univ., Sendai (Japan). Inst. of Materials Research Nippon Steel Corp., Tokyo (Japan)); Takai, S. (Tohoku Univ., Sendai (Japan). Inst. of Materials Research); Kimura, H. (Tohoku Univ., Sendai (Japan). Inst. of Materials Research)

    1992-02-01

    Mode of fracture and ductile-brittle transition temperature (DBTT) of high purity iron( 99.999% or higher ) was investigated by using two sets of specimens of different grain boundary character. The specimens having bamboo-type grain structure with high angle boundaries have fractured in the intergranular mode and their DBTT is between 110 and 125 K. Specimens with coarse grain structure have shown fractures in transgranular mode at and below 50 K. DBTT for intergranular fracture(IGF), if any, has been below 4.2 K and this has been in contrast with the the occurance of IGF even at 77K for less pure iron specimens(99.99 % or below). It has been concluded that DBTT for IGF, which has been the common fracture mode in pure iron depends strongly on the purity and grain boundary character of iron spocimens. DBTT has ranged from 125 to 4.2 K or below. Also, specimens of 99.99 % purity have been more susceptible to IGF than the specimens with 99.999 % purity. 8 refs., 6 figs.

  7. A Study of the Surface Quality of High Purity Copper after Heat Treatment

    CERN Document Server

    Aicheler, M; Atieh, S; Calatroni, S; Riddone, G; Lebet, S; Samoshkin, A

    2011-01-01

    Themanufacturing flow of accelerating structures for the compact linear collider, based on diamond-machined high purity copper components, include several thermal cycles (diffusion bonding, brazing of cooling circuits, baking in vacuum, etc.). The high temperature cycles may be carried out following different schedules and environments (vacuum, reducing hydrogen atmosphere, argon, etc.) and develop peculiar surface topographies which have been the object of extended observations. This study presents and discusses the results of scanning electron microscopy (SEM) and optical microscopy investigations.

  8. Preparation and characterization of high purity β-chitin from squid pens (Loligo chenisis).

    Science.gov (United States)

    Cuong, Hoang Ngoc; Minh, Nguyen Cong; Van Hoa, Nguyen; Trung, Trang Si

    2016-12-01

    Squid pens were extracted by a NaOH solution at 80°C for 10h to remove protein and minerals. The as-prepared β-chitin had a high molecular weight (8.5±0.1×10 3 kDa), a low protein content (0.63±0.02wt.%), and a negligible amount of minerals. This method avoids the conventional method for the removal of minerals from shrimp and crab shells by HCl. The purity of resulting products was measured by NMR and FTIR. Moreover, the morphology and crystallinity of β-chitin was characterized by SEM and XRD. The β-chitin with long chains and high purity is suitable for producing high quantity β-chitosan for various potential applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Approaches to the accurate characterization of high purity metal fluorides and fluoride glasses

    Science.gov (United States)

    Beary, E. S.; Paulsen, P. J.; Rains, T. C.; Ewing, K. J.; Jaganathan, J.; Aggarwal, I.

    1990-11-01

    The analytical challenges posed by the measurement of trace contaminants in high purity metal fluorides require that innovative chemical preparation procedures be used to enhance existing instrumental techniques. The instrumental techniques used to analyze these difficult matrices must be sensitive enough to detect extremely low levels of trace impurities, and the background interferences derived from the matrix (metal fluoride or glass) must be minimized. A survey of analytical techniques that have the necessary characteristics to analyze these materials will be given. In addition, means of controlling the chemical blank will be presented. Mass and atomic spectrometric techniques will be discussed, specifically graphite furnace atomic absorption spectrometry (GFAAS) and inductively coupled plasma-mass spectrometry (ICP-MS). Analytical procedures using GFAAS and ICP-MS have been developed to determine sub ppb (part per billion) levels of contaminants in high purity fluoride materials.

  10. Dislocation mobility mechanisms at medium temperatures in very high purity lead (99.9999%)

    International Nuclear Information System (INIS)

    Gallego, I.; No, M.L.; San Juan, J.

    1998-01-01

    The internal friction spectrum of high purity lead (99.9999%) at medium temperatures has been studied. A new peak (P 1 ) has been found at 240 K, which has not been studied up to now. The activation energy of the process associated with P 1 has been determined and its experimental behaviour has also been systematically studied. The comparison between the results and the theoretical predictions of the models of dislocation mobility allows us to attribute the P 1 peak to the sliding of dislocations controlled by the climbing of jogs induced by the diffusion of vacancies along the dislocation line. This conclusion is analogue to that obtained in previous works for the P 1 peak in very high purity aluminium (99.9999%). (Author) 13 refs

  11. Fabrication of novel cryomill for synthesis of high purity metallic nanoparticles

    Science.gov (United States)

    Kumar, Nirmal; Biswas, Krishanu

    2015-08-01

    The successful preparation of free standing metal nanoparticles with high purity in bulk quantity is the pre-requisite for any potential application. This is possible by using ball milling at cryogenic temperature. However, the most of ball mills available in the market do not allow preparing high purity metal nanoparticles by this route. In addition, it is not possible to carry out in situ measurements of process parameters as well as diagnostic of the process. In the present investigation, we present a detailed study on the fabrication of a cryomill, which is capable of avoiding contaminations in the product. It also provides in situ measurements and diagnostic of the low temperature milling process. Online monitoring of the milling temperature and observation of ball motion are the important aspects in the newly designed mill. The nanoparticles prepared using this fabricated mill have been found to be free standing and also free from contaminations.

  12. The European Expression Of Interest For High Purity U-233 Materials

    Energy Technology Data Exchange (ETDEWEB)

    Giaquinto, Joseph M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Younkin, James R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-04-01

    The purpose of this letter report is to document the response for an Expression of Interest (EOI) sent to the European Safeguards and research and development (R&D) scientific communities for the distribution of small amounts of high purity 233U materials for use in safeguards, nonproliferation, and basic R&D in the nuclear disciplines. The intent for the EOI was to gauge the level of international interest for these materials from government and research institutions with programmatic missions in the nuclear security or nuclear R&D arena. The information contained herein is intended to provide information to assist key decision makers in DOE as to the ultimate disposition path for the high purity materials currently being recovered at Oak Ridge National Laboratory (ORNL) and only those items for which there is no United States (U.S.) sponsor identified.

  13. Perfomance of a high purity germanium multi-detector telescope for long range particles

    International Nuclear Information System (INIS)

    Riepe, G.; Protic, D.; Suekoesd, C.; Didelez, J.P.; Frascaria, N.; Gerlic, E.; Hourani, E.; Morlet, M.

    1980-01-01

    A telescope of stacked high purity germanium detectors designed for long range charged particles was tested using medium energy protons. Particle identification and the rejection of the low energy tail could be accomplished on-line allowing the measurement of complex spectra. The efficiency of the detector stack for protons was measured up to 156 MeV incoming energy. The various factors affecting the energy resolution are discussed and their estimated contributions are compared with the experimental results

  14. Aluminium. II - A review of deformation properties of high purity aluminium and dilute aluminium alloys.

    Science.gov (United States)

    Reed, R. P.

    1972-01-01

    The elastic and plastic deformation behavior of high-purity aluminum and of dilute aluminum alloys is reviewed. Reliable property data, including elastic moduli, elastic coefficients, tensile, creep, fatigue, hardness, and impact are presented. Single crystal tensile results are discussed. Rather comprehensive reference lists, containing publications of the past 20 years, are included for each of the above categories. Defect structures and mechanisms responsible for mechanical behavior are presented. Strengthening techniques (alloys, cold work, irradiation, quenching, composites) and recovery are briefly reviewed.

  15. Corrosion behavior of high purity Fe-Cr-Ni alloys in trans-passive condition

    International Nuclear Information System (INIS)

    Mayuzumi, Masami; Ohta, Jyoji; Kako, Kenji

    1998-01-01

    The corrosion behavior of high-purity (99.99%) Fe-Cr-Ni alloys was investigated in 13 N nitric acid with/without Ce 4+ ions to clarify the effect of impurities on the trans-passive corrosion of stainless steel. The following results were obtained. (1) Almost no intergranular corrosion was observed in the high-purity alloys, although the corrosion rate of the matrix region was nearly the same as that of a commercial stainless steel with the same Cr and Ni content. (2) Due to the improved intergranular corrosion resistance, the effect of the purification became significant in the corrosion condition with the grain-separation being predominant. (3) The high-purity alloys showed higher susceptivility to intergranular corrosion with aging treatment between 873 K and 1073 K. Although the sulfuric acid/copper sulfate test suggested the formation of Cr-depleted zones, a grain boundary micro-analysis using a FETEM with an EDX did not reveal any change in Cr content or impurity segregain along the grain boundaries. The mechanism of corrosion enhancement resulting from the aging treatment remains nuclear. (author)

  16. High purity heavy water production: need for total organic carbon determination in process water streams

    International Nuclear Information System (INIS)

    Ayushi; Kumar, Sangita D.; Reddy, A.V.R.; Vithal, G.K.

    2009-01-01

    In recent times, demand for high purity heavy water (99.98% pure) in industries and laboratories has grown by manifold. Its application started in nuclear industry with the design of CANDU reactor, which uses natural uranium as fuel. In this reactor the purest grade of heavy water is used as the moderator and the primary coolant. Diverse industrial applications like fibre optics, medicine, semiconductors etc. use high purity heavy water extensively to achieve better performance of the specific material. In all these applications there is a stringent requirement that the total organic carbon content (TOC) of high purity heavy water should be very low. This is because the presence of TOC can lead to adverse interactions in different applications. To minimize the TOC content in the final product there is a need to monitor and control the TOC content at each and every stage of heavy water production. Hence a simple, rapid and accurate method was developed for the determination of TOC content in process water samples. The paper summarizes the results obtained for the TOC content in the water samples collected from process streams of heavy water production plant. (author)

  17. In vitro characterization of high purity factor IX concentrates for the treatment of hemophilia B.

    Science.gov (United States)

    Limentani, S A; Gowell, K P; Deitcher, S R

    1995-04-01

    This study employed sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis and immunoblotting to assess the purity of seven high purity factor IX concentrates: Aimafix (Aima), AlphaNine-SD (Alpha Therapeutic), Factor IX VHP (Biotransfusion), Immunine (Immuno), Mononine (Armour Pharmaceutical), Nanotiv (Kabi Pharmacia), and 9MC (Blood Products Laboratory). The mean specific activity of these products ranged from 68 U factor IX/mg (Aimafix) to 246 U factor IX/mg (Mononine). SDS-PAGE analysis showed that the highest purity product, Mononine, had a single contaminating band under non-reducing conditions. Two additional bands were detected when this product was analyzed under reducing conditions. All other products had multiple contaminating bands that were more apparent under reducing than non-reducing conditions. The immunoblot for factor IX showed a dominant factor IX band for all products. In addition, visible light chain of factor IX was detected for AlphaNine-SD, Factor IX VHP, Immunine, Mononine, Nanotiv, and 9MC, suggesting that the factor IX in these products had undergone partial activation to factor IXa. Another contaminating band was visible at 49,500 for all of the products except 9MC. In addition to this band, high molecular weight contaminants were apparent for some products, most notably AlphaNine-SD. The identity of these bands is unknown. Immunoblotting failed to demonstrate factor VII as a contaminant of any of the high purity products, although factor VIIa could be detected in some lots of Immunine, Nanotiv, and 9MC by a clot-based assay. Factor X contaminated Aimafix, AlphaNine-SD, Factor IX VHP, Immunine, Nanotiv, and 9MC, but activation products of factor X were not detected.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. High-energy proton radiation damage of high-purity germanium detectors

    International Nuclear Information System (INIS)

    Pehl, R.H.; Varnell, L.S.; Metzger, A.E.

    1977-10-01

    Motivated by their applicability to gamma-ray spectroscopy experiments in space, quantitative studies of radiation damage effects in high-purity germanium detectors due to high-energy charged particles have been initiated with the irradiation by 6 GeV/c protons of two 1.0 cm thick planar detectors maintained at 88 0 K. The threshold for resolution degradation and the annealing characteristics differs markedly from those previously observed for detectors irradiated by fast neutrons. Under proton bombardment, degradation in the energy resolution was found to begin below 7 x 10 7 protons/cm 2 , and increased proportionately in both detectors until the experiment was terminated at a total flux of 5.7 x 10 8 protons/cm 2 , equivalent to about a six year exposure to cosmic-ray protons in space. At the end of the irradiation, the FWHM resolution measured at 1332 keV stood at 8.5 and 13.6 keV, with both detectors of only marginal utility as a spectrometer due to the severe tailing caused by charge trapping. The two detectors displayed a significant difference in proton damage sensitivity, which is consistent with fast neutron damage effects. To ensure that detector variability did not influence the comparison of proton- and neutron-induced damage effects, one of the detectors had been used previously in a neutron damage experiment. The threshold for high-energy proton damage was found to be markedly lower, roughly 5 x 10 7 protons/cm 2 , compared to 3 x 10 9 neutrons/cm 2 for fast neutrons. Annealing these detectors after proton damage was found to be much easier than after neutron damage. A satisfactory level of recovery after high-energy proton damage can be achieved with in-situ annealing in the range of 100 0 C

  19. Amorphous germanium as an electron or hole blocking contact on high-purity germanium detectors

    International Nuclear Information System (INIS)

    Hansen, W.L.; Haller, E.E.

    1976-10-01

    Experiments were performed in an attempt to make thin n + contacts on high-purity germanium by the solid phase/sup 1)/ epitaxial regrowth of arsenic doped amorphous germanium. After cleaning the crystal surface with argon sputtering and trying many combinations of layers, it was not found possible to induce recrystallization below 400 0 C. However, it was found that simple thermally evaporated amorphous Ge made fairly good electron or hole blocking contacts. Excellent spectrometers have been made with amorphous Ge replacing the n + contact. As presently produced, the amorphous Ge contact diodes show a large variation in high-voltage leakage current

  20. Synthesis and characterization of straight and stacked-sheet AlN nanowires with high purity

    International Nuclear Information System (INIS)

    Lei, M.; Yang, H.; Li, P.G.; Tang, W.H.

    2008-01-01

    Large-scale AlN nanowires with hexagonal crystal structure were synthesized by the direct nitridation method at high temperatures. The experimental results indicate that these single-crystalline AlN nanowires have high purity and consist of straight and stacked-sheet nanowires. It is found that straight AlN nanowire grows along [1, 1, -2, 0] direction, whereas the stacked-sheet nanowire with hexagonal cross section is along [0 0 0 1] direction. It is thought that vapor-solid (VS) mechanism should be responsible for the growth of AlN nanowires

  1. Development of low-loss cryo-accelerating structure with high-purity copper

    Science.gov (United States)

    Iino, Akihiro; Yamaguchi, Seiya; Shintomi, Takakazu; Higo, Toshiyasu; Funahashi, Yoshisato; Matsumoto, Shuji; Michizono, Shinichiro; Ueno, Kenji; Endo, Katsumi

    2017-09-01

    In this paper, the development of an accelerating structure with high-purity copper operated at approximately 20 K is described. The aim is to obtain a dramatic increase in the quality factor (Q factor), which is an important parameter as regards enhancement of the acceleration gradient in a normal-conducting accelerating structure that has been operated at room temperature in the past. First, the Q factors of pillbox cavities comprised of two types of copper with different purities (99.99% and 99.99998%) were measured, at room temperature (300 K) and at a relatively low temperature (20 K); the resultant ratios, Q0(20 K)/Q0(300 K), were then compared with calculated values. Hence, it was found that the experimental and calculated values agree to within several percent, and converge to a constant value (approximately 5.3) when the residual resistance ratio is above 500. Next, a C-band accelerating structure was fabricated using a copper material having a purity of 99.99998%, and high-power testing of the structure was conducted at 20 K. Hence, it was found that the accelerating gradient Eacc reaches 30.9 MV/m with a 1.0- μs pulse width and 50-Hz repetition rate. In the high-power test, it was revealed that the radiation dose rate for C-band structure (20 K) was about two orders of magnitude lower than that for S-band structure (303 K) under the same conditions. Further, the magnitude of the dark current generated in this structure was estimated to be several femtoamps, which was below the detection limit. This finding was based on the assumption that the dark current magnitude is proportional to the radiation dose; however, no dark current was observed.

  2. Gain limits of a Thick GEM in high-purity Ne, Ar and Xe

    CERN Document Server

    Miyamoto, J; Peskov, V

    2010-01-01

    The dependence of the avalanche charge gain in Thick Gas Electron Multipliers (THGEM) on the purity of Ne, Ar and Xe filling gases was investigated. The gain, measured with alpha-particles in standard conditions (atmospheric pressure, room temperature), was found to considerably drop in gases purified by non-evaporable getters. On the other hand, small N2 admixtures to noble gases resulted in high reachable gains. The results are of general relevance in the operation of gas-avalanche detectors in noble gases, particularly that of two-phase cryogenic detectors for rare events.

  3. Determination of lead in high-purity silver. Comparison between photon activation and atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Loos-Neskovic, C.; Fedoroff, M.; Revel, G.

    1978-01-01

    A chemical separation based on the fixation of silver on nickel ferrocyanide was studied. It was applied to the determination of lead in silver by photon-activation or atomic absorption spectrometry. The first method gave a detection limit of 0.1 μg. The second one could not be applied for concentration less than 50 μg/g, owing to loss by adsorption. Analytical results showed that lead is one of the major metallic impurity in high purity silver. (author)

  4. Damage process of high purity tungsten coatings by hydrogen beam heat loads

    International Nuclear Information System (INIS)

    Tamura, S.; Tokunaga, K.; Yoshida, N.; Taniguchi, M.; Ezato, K.; Sato, K.; Suzuki, S.; Akiba, M.; Tsunekawa, Y.; Okumiya, M.

    2005-01-01

    To investigate the synergistic effects of heat load and hydrogen irradiation, cyclic heat load tests with a hydrogen beam and a comparable electron beam were performed for high purity CVD-tungsten coatings. Surface modification was examined as a function of the peak temperature by changing the heat flux. Scanning Electron Microscopy analysis showed that the surface damage caused by the hydrogen beam was more severe than that by the electron beam. In the hydrogen beam case, cracking at the surface occurred at all peak temperatures examined from 300 deg. C to 1600 deg. C. These results indicate that the injected hydrogen induces embrittlement for the CVD-tungsten coating

  5. A fundamental self-generated quenching center for lanthanide-doped high-purity solids

    International Nuclear Information System (INIS)

    Auzel, F.

    2002-01-01

    An intrinsic self-generated quenching center for lanthanide-doped high-purity solids is presented for transitions, which cannot be quenched by cross-relaxation. This center, in fact a cluster-like pair of active centers, is shown to come from a particular multiphonon-assisted energy transfer between them. Being due to the vibronic properties of the host it cannot be suppressed. Its role in lanthanide first excited states self-quenching is analyzed and a simple mathematical expression is derived. This law is compared with experimental results for self-quenching in Er-doped fluorophosphate glasses

  6. Impurity removal process for high-purity silica production by acid leaching

    Directory of Open Access Journals (Sweden)

    Ezzaouia H.

    2012-06-01

    Full Text Available In our days obtaining silica sand with very high purity is a primordial stage in photovoltaic industry. The effects of acids on the removal of impurity from silica sand have been studied using leaching acids: mixture composed of HF/HCl/H2O with a volume composition of (1:7:24.The obtained material was characterized using Ultraviolet-Visible absorbance (UV-Vis and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES. Results of the application of this technique show a significant reduction of the amounts of undesirable impurities present in natural silica (such as Co, Fe, Ca, Al, Mg ….

  7. Influence of Carbon and Nitrogen on Corrosion Resistance of High Purity Fe-50mass % Cr Alloy

    OpenAIRE

    Kato, Y.; Ujiro, T.; Satoh, S.; Yamato, K.; Abiko, K.

    1995-01-01

    High purity Fe-50mass%Cr alloys containing (C+N) in the range of 30 to 500 mass ppm were prepared and their corrosion resistance was investigated. Pitting potential in a 3.5mass%NaCl solution at 343K rose with reducing (C+N) content. Alloys containing (C+N) at less than 100 mass ppm did not sustain pitting corrosion. However, alloys containing 500 mass ppm (C+N) corroded severely in 6%FeCl3+1/20N HCl solutions. Heat treatment at 923K was recognized as influencing corrosion resistance due to p...

  8. Selective dispersion of high-purity semiconducting carbon nanotubes using indacenodithiophene-based conjugated polymer

    Science.gov (United States)

    Ji, Dongseob; Lee, Seung-Hoon; Noh, Yong-Young

    2018-01-01

    The facile sorting of highly pure semiconducting single-walled carbon nanotubes (s-SWNTs) is still one of the challenging issues for the next-generation wearable electronic devices such as various opto-electric devices and field-effect transistors (FETs). Herein, we demonstrate the selective dispersion of high-purity s-SWNTs using indacenodithiophene-co-benzothiadiazole (IDT-BT), which is a state-of-the-art high-mobility conjugated polymer. By the selective wrapping of the IDT-BT copolymer, SWNTs of chiral indices (6, 5), (7, 5), (7, 6), (8, 4), (9, 4), (8, 6), (8, 7), (10, 5), (9, 7), (10, 6), (11, 1), and (13, 3) are sorted. Finally, the networked s-SWNT film formed by spin-coating is applied as an active layer of FETs that exhibited ambipolar characteristics with an average mobility of 2.28 cm2/V s in the p-channel and 2.10 cm2/V s in the n-channel. The ON/OFF ratios in both p- and n-channels are approximately 105, which supports the high purity separation of s-SWNTs wrapped by IDT-BT.

  9. High-Purity Nickel Prepared by Electron Beam Melting: Purification Mechanism

    Science.gov (United States)

    Zhang, Tao; Shang, Zaiyan; Chen, Ming; He, Jinjiang; Lv, Baoguo; Wang, Xingquan; Xiong, Xiaodong

    2013-12-01

    A bulk cylindrical high-purity nickel ingot, with purity of more than 99.999 pct (5N) in mass, was obtained from the raw nickel with 99.95 pct (3N5) initial purity by virtue of double electron beam melting (EBM). A chemical analysis was performed by using glow discharge mass spectrometry (GDMS) analysis for all elements in the periodic table except carbon, nitrogen, and oxygen, which were tested by the high-performance combustion and fusion method. The major impurities B, Na, Al, Si, P, S, Ca, Ti, Cr, Fe, Cu, Co, Zn, As, Ag, Sb, and Pb showed an excellent removal effect with removal efficiency of more than 85 pct following the double EBMs. Li, Mg, Cl, K, V, Mn, Ga, Ge, Cd, Se, In, Sn, Tl, Au, and Pt were below the detection limit. No significant change in concentration was found for the refractory elements W, Mo, Ta, Nb, and Ir. Be, F, Sc, Se, Br, Rb, Sr, Zr, Y, Ru, Rh, Pd, Te, I, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Re, Os, Hg, Bi, Th, and U were not detectable following the purification as compared to the raw nickel. Gaseous impurities, C, N, O, especially for N, was removed sufficiently. Theoretical calculations for removal efficiency of impurity Fe based on the calculated vapor pressure, activity coefficient, and melt temperature were in good agreement with measured results, and the purification mechanism was ascribed to the evaporation of major impurities and subsequently evacuation by repetitive EBM.

  10. SIMULTANEOUS PRODUCTION OF HIGH-PURITY HYDROGEN AND SEQUESTRATION-READY CO2 FROM SYNGAS

    Energy Technology Data Exchange (ETDEWEB)

    Linda Denton; Hana Lorethova; Tomasz Wiltowski; Court Moorefield; Parag Kulkarni; Vladimir Zamansky; Ravi Kumar

    2003-12-01

    This final report summarizes the progress made on the program ''Simultaneous Production of High-Purity Hydrogen and Sequestration-Ready CO{sub 2} from Syngas (contract number DE-FG26-99FT40682)'', during October 2000 through September of 2003. GE Energy and Environmental Research (GE-EER) and Southern Illinois University (SIU) at Carbondale conducted the research work for this program. This program addresses improved methods to efficiently produce simultaneous streams of high-purity hydrogen and separated carbon dioxide from synthesis gas (syngas). The syngas may be produced through either gasification of coal or reforming of natural gas. The process of production of H{sub 2} and separated CO{sub 2} utilizes a dual-bed reactor and regenerator system. The reactor produces hydrogen and the regenerator produces separated CO{sub 2}. The dual-bed system can be operated under either a circulating fluidized-bed configuration or a cyclic fixed-bed configuration. Both configurations were evaluated in this project. The experimental effort was divided into lab-scale work at SIU and bench-scale work at GE-EER. Tests in a lab-scale fluidized bed system demonstrated the process for the conversion of syngas to high purity H{sub 2} and separated CO{sub 2}. The lab-scale system generated up to 95% H{sub 2} (on a dry basis). Extensive thermodynamic analysis of chemical reactions between the syngas and the fluidized solids determined an optimum range of temperature and pressure operation, where the extent of the undesirable reactions is minimum. The cycling of the process between hydrogen generation and oxygen regeneration has been demonstrated. The fluidized solids did not regenerate completely and the hydrogen purity in the reuse cycle dropped to 70% from 95% (on a dry basis). Changes in morphology and particle size may be the most dominant factor affecting the efficiency of the repeated cycling between hydrogen production and oxygen regeneration. The concept of

  11. Change of sheet resistance of high purity alumina ceramics implanted by Cu and Ti ions

    International Nuclear Information System (INIS)

    Li Dexing; Zhang Jizhong; Yu Miao; Kang Jianchang; Li Wenzhi

    2005-01-01

    High purity alumina ceramics (99% Al 2 O 3 ) was implanted by copper ion and titanium ion in a metal vapour vacuum arc (MEVVA) implanter, respectively. The influence of implantation parameters was studied varying ion fluence. The samples were implanted by 68 keV Cu ion and 82 keV Ti ion with fluences from 1 x 10 15 to 1 x 10 18 ions/cm 2 , respectively. The as-implanted samples were investigated by scanning electron microscopy (SEM), glancing X-ray diffraction (GXRD), scanning Auger microscopy (SAM), and four-probe method. Different morphologies were observed on the surfaces of the as-implanted samples and clearly related to implantation parameters. For both ion implantations, the sheet resistances of the alumina samples implanted with Cu and Ti ion fluences of 1 x 10 18 ions/cm 2 , respectively, reached the corresponding minimum values because of the surface metallization. The experimental results indicate that the high-fluence ion implantation resulted in conductive layer on the surface of the as-implanted high purity alumina ceramics

  12. Preparation of High Purity CdTe for Nuclear Detector: Electrical and Nuclear Characterization

    Science.gov (United States)

    Zaiour, A.; Ayoub, M.; Hamié, A.; Fawaz, A.; Hage-ali, M.

    High purity crystal with controllable electrical properties, however, control of the electrical properties of CdTe has not yet been fully achieved. Using the refined Cd and Te as starting materials, extremely high-purity CdTe single crystals were prepared by the traditional vertical THM. The nature of the defects involved in the transitions was studied by analyzing the position of the energy levels by TSC method. The resolution of 4.2 keV (FWHM) confirms the high quality and stability of the detectors: TSC spectrum was in coherence with detectors spectrum with a horizontal plate between 0.2 and 0.6 eV. The enhancement in resolution of detectors with a full width at half- maximum (less than 0.31 meV), lead to confirm that the combination of vacuum distillation and zone refining was very effective to obtain more purified CdTe single crystals for photovoltaic or nuclear detectors with better physical properties.

  13. Obtention of high purity silica from the flotation waste of itabiritic ore

    International Nuclear Information System (INIS)

    Martins, Polyana Fabricia Fernandes

    2016-01-01

    Banded iron formations are exploited as iron mineral in 'Quadrilatero Ferrifero' of Minas Gerais (MG) State, Brazil. About half of the amount of extracted material becomes tailings, which are stored in tailing dams or used for filling mining pits. Tens of thousands of tons are generated daily in operating mines in this region, causing concern about the environmental liabilities, and costs to manage the tailing dams. Miners are committed to finding uses for these wastes in other productive chains. This thesis aimed to obtain high purity silica from the flotation tailings of banded iron formations using classical techniques for ore processing, such as particle size classification and magnetic separation, followed by hydrometallurgical leaching, also alkaline fusion and chemical precipitation. The tailings samples was collected in the tailings dam of Peak Mine operated by Vale A.S., in Itabirito – MG. This sample had initially 33.4% by weight SiO 2 , 57.4% wt Fe 2 O 3 and 8.31% wt Al 2 O 3 . After desliming for disposal of the fine particles (-37μm) the composition was 68.0% SiO 2 , 31.4% Fe 2 O 3 and 0.50% Al 2 O 3 . After magnetic separation, the composition was 93.8% SiO 2 , 1.16% Fe 2 O 3 and 3.80% Al 2 O 3 . After acid leaching l or digestion to remove impurities, it was possible to obtain silica with 98% purity. The fusion with sodium hydroxide, followed by alkaline leaching of sodium silicate and silica precipitation gave purities of about 99.5%. Values even higher may be possible with optimization of the parameters of alkaline fusion or by repeating the process from the product with purity of 99.5%. The iron oxide content and the aluminum main contaminants were 0.01% and 0.07%, respectively. Amorphous silica was obtained with high specific surface (322 m 2 /g) and particle size less than 200 nm. Depending on the application, a control should be made for the impurities, such as phosphorus, potassium and boron. (author)

  14. High resolution gamma-ray spectroscopy at high count rates with a prototype High Purity Germanium detector

    Science.gov (United States)

    Cooper, R. J.; Amman, M.; Vetter, K.

    2018-04-01

    High-resolution gamma-ray spectrometers are required for applications in nuclear safeguards, emergency response, and fundamental nuclear physics. To overcome one of the shortcomings of conventional High Purity Germanium (HPGe) detectors, we have developed a prototype device capable of achieving high event throughput and high energy resolution at very high count rates. This device, the design of which we have previously reported on, features a planar HPGe crystal with a reduced-capacitance strip electrode geometry. This design is intended to provide good energy resolution at the short shaping or digital filter times that are required for high rate operation and which are enabled by the fast charge collection afforded by the planar geometry crystal. In this work, we report on the initial performance of the system at count rates up to and including two million counts per second.

  15. Wet routes of high purity BaTiO3 nanopowders

    International Nuclear Information System (INIS)

    Wang Liqiu; Liu Liang; Xue Dongfeng; Kang Hongmin; Liu Changhou

    2007-01-01

    High purity BaTiO 3 nanopowders were prepared in wet routes through stearic acid gel (SAG) and acetic acid gel (AAG) techniques, respectively. BaTiO 3 samples were characterized by X-ray diffraction, transmission electron microscope, Fourier transform infrared spectrometry, X-ray fluorescence spectrometry, and thermal gravimetric analysis. The present results indicate that both methods have a similar reaction process during calcination, while BaTiO 3 crystallites were initially formed at 550 deg. C by SAG and 800 deg. C by AAG. Both methods could produce BaTiO 3 powders with a cubic perovskite structure, while they had different grain size distributions within 25-50 nm for SAG and 50-80 nm for AAG. BaTiO 3 samples prepared by SAG had a lower agglomeration than those by AAG. SAG has shown many distinctive advantages in the preparation of high purity BaTiO 3 nanopowders, without Ba and Ti losses and hazardous wastes

  16. High purity silver microcrystals recovered from silver wastes by eco-friendly process using hydrogen peroxide.

    Science.gov (United States)

    Gatemala, Harnchana; Ekgasit, Sanong; Wongravee, Kanet

    2017-07-01

    A simple, rapid, and environmentally friendly process using hydrogen peroxide, was developed for recovering high purity silver directly from industry and laboratory wastes. Silver ammine complex, [Ag(NH 3 ) 2 ] + Cl - , derived from AgCl were generated and then directly reduced using H 2 O 2 to reliably turn into high purity microcrystalline silver (99.99%) examined by EDS and XRD. Morphology of the recovered silver microcrystals could be selectively tuned by an addition of poly(vinyl pyrrolidone). The main parameters in the recovering process including pH, concentration of Ag + and the mole ratio of H 2 O 2 :Ag + were carefully optimized though the central composite design (CCD). The optimized condition was employed for a trial recovery of 50 L silver ammine complex prepared from a collection of silver-wastes during 3-year research on industrial nanoparticle production. The recovered silver microcrystals >700 g could be recovered with 91.27%. The remaining solution after filtering of the recovered silver microcrystals can be used repeatedly (at least 8 cycles) without losing recovery efficiency. Matrix interferences including Pb 2+ and Cl - play a minimal role in our silver recovery process. Furthermore, the direct usage of the recovered silver microcrystals was demonstrated by using as a raw material of silver clay for creating a set of wearable silver jewelries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Effect of initial grain size on dynamic recrystallization in high purity austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    El Wahabi, M. [Centre SMS, CNRS UMR 5146, Ecole Nationale Superieure des Mines de Saint-Etienne, 158, cours Fauriel-42023, Saint-Etienne Cedex 2 (France); Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, ETSEIB - Universidad Politecnica de Cataluna, Av. Diagonal 647, 08028-Barcelona (Spain); Gavard, L. [Centre SMS, CNRS UMR 5146, Ecole Nationale Superieure des Mines de Saint-Etienne, 158, cours Fauriel-42023, Saint-Etienne Cedex 2 (France); Montheillet, F. [Centre SMS, CNRS UMR 5146, Ecole Nationale Superieure des Mines de Saint-Etienne, 158, cours Fauriel-42023, Saint-Etienne Cedex 2 (France); Cabrera, J.M. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, ETSEIB - Universidad Politecnica de Cataluna, Av. Diagonal 647, 08028-Barcelona (Spain)]. E-mail: jose.maria.cabrera@upc.edu; Prado, J.M. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, ETSEIB - Universidad Politecnica de Cataluna, Av. Diagonal 647, 08028-Barcelona (Spain)

    2005-10-15

    The influence of initial microstructure on discontinuous dynamic recrystallization (DDRX) has been investigated by using high purity and ultra high purity austenitic stainless steels with various initial grain sizes. After uniaxial compression tests at constant strain rates and various temperatures, the steady state microstructure or the state corresponding to the maximum strain ({epsilon} = 1) attained in the test was analyzed by scanning electron microscopy aided with automated electron back scattering diffraction. Recrystallized grain size d {sub rec} and twin boundary fraction f {sub TB} measurements were carried out. The mechanical behavior was also investigated by comparing experimental stress-strain curves with various initial grain sizes. DDRX kinetics was described by the classical Avrami equation. It was concluded that larger initial grain sizes promoted a delay in the DDRX onset in the two alloys. It was also observed that the softening process progressed faster for smaller initial grain sizes. The effect of initial grain size is larger in the HP material and becomes more pronounced at low temperature.

  18. Recovery of high purity sulfuric acid from the waste acid in toluene nitration process by rectification.

    Science.gov (United States)

    Song, Kai; Meng, Qingqiang; Shu, Fan; Ye, Zhengfang

    2013-01-01

    Waste sulfuric acid is a byproduct generated from numerous industrial chemical processes. It is essential to remove the impurities and recover the sulfuric acid from the waste acid. In this study the rectification method was introduced to recover high purity sulfuric acid from the waste acid generated in toluene nitration process by using rectification column. The waste acid quality before and after rectification were evaluated using UV-Vis spectroscopy, GC/MS, HPLC and other physical and chemical analysis. It was shown that five nitro aromatic compounds in the waste acid were substantially removed and high purity sulfuric acid was also recovered in the rectification process at the same time. The COD was removed by 94% and the chrominance was reduced from 1000° to 1°. The recovered sulfuric acid with the concentration reaching 98.2 wt% had a comparable quality with commercial sulfuric acid and could be recycled back into the toluene nitration process, which could avoid waste of resources and reduce the environmental impact and pollution. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. High-Purity Semiconducting Single-Walled Carbon Nanotubes: A Key Enabling Material in Emerging Electronics.

    Science.gov (United States)

    Lefebvre, Jacques; Ding, Jianfu; Li, Zhao; Finnie, Paul; Lopinski, Gregory; Malenfant, Patrick R L

    2017-10-17

    Semiconducting single-walled carbon nanotubes (sc-SWCNTs) are emerging as a promising material for high-performance, high-density devices as well as low-cost, large-area macroelectronics produced via additive manufacturing methods such as roll-to-roll printing. Proof-of-concept demonstrations have indicated the potential of sc-SWCNTs for digital electronics, radiofrequency circuits, radiation hard memory, improved sensors, and flexible, stretchable, conformable electronics. Advances toward commercial applications bring numerous opportunities in SWCNT materials development and characterization as well as fabrication processes and printing technologies. Commercialization in electronics will require large quantities of sc-SWCNTs, and the challenge for materials science is the development of scalable synthesis, purification, and enrichment methods. While a few synthesis routes have shown promising results in making near-monochiral SWCNTs, gram quantities are available only for small-diameter sc-SWCNTs, which underperform in transistors. Most synthesis routes yield mixtures of SWCNTs, typically 30% metallic and 70% semiconducting, necessitating the extraction of sc-SWCNTs from their metallic counterparts in high purity using scalable postsynthetic methods. Numerous routes to obtain high-purity sc-SWCNTs from raw soot have been developed, including density-gradient ultracentrifugation, chromatography, aqueous two-phase extraction, and selective DNA or polymer wrapping. By these methods (termed sorting or enrichment), >99% sc-SWCNT content can be achieved. Currently, all of these approaches have drawbacks and limitations with respect to electronics applications, such as excessive dilution, expensive consumables, and high ionic impurity content. Excess amount of dispersant is a common challenge that hinders direct inclusion of sc-SWCNTs into electronic devices. At present, conjugated polymer extraction may represent the most practical route to sc-SWCNTs. By the use of

  20. Recovery of high purity proteins from polyacrylamide gels using ultraviolet scanning densitometry

    International Nuclear Information System (INIS)

    Bartolini, P.; Arkaten, R.; Ribela, M.T.C.P.

    1988-07-01

    We present here a technique for the purification of proteins carried out by a quantitative analytical method used in conjunction with a preparative gel electrophoresis. Both methods employ densitometric ultraviolet scanning of unstained protein bands, a procedure wich is particulary suitable for the purification and recovery of biologically active polypeptides. In short, the purified extracted protein, isolated in a segment cut out from a preparative gel, is recovered by a second (reversed) electrophoresis. We performed the extractions and recoveries of different amounts of two standard proteins (BSA and STI) and a polypeptide hormone (hGH). Our main interest, especially for the hormone is the complete protein recovery with retention of bio and immunoactivity and high purity. For the proteins tested, the mean recovery was of 93 + - 5% obtaining a mean purity of 95 + - 7%. We conclude that the proposed method should have interesting applications, particularly in the obtention of very pure hormones, as are needed for radioligand assays, for radiolabelling and specific antibody raising. We emphasize the simplicity and rapidity of the method (the entire preparative process: first electrophoresis, UV scanning and reversed electrophoresis can be performed in approximately six hours) and its efficiency in recovering pure proteins even on a milligram scale. We thank the support from the IAEA (4299/RB) and FINEP (43.86.0351.00) and CENE (Brazil). (author) [pt

  1. Radiochemical neutron activation analysis based multi-elemental analysis of high purity gallium

    International Nuclear Information System (INIS)

    Tashimova, F.A.; Sadikov, I.I; Salimov, M.I.; Zinov'ev, V.G.

    2006-01-01

    Full text: Gallium is one of the widely used materials in semiconductor and optoelectronics industry. Gallium is used to produce infrared detectors, piezoelectric sensors, high- and low-temperature transistors for space and defense technology. One of the most important requirements for semiconductor materials of gallium compounds is an excessive high purity for layers and films. Information on impurities (type of an impurity, concentration, character of distribution) is important as for better understanding of the physical and chemical processes taking place in formed semiconductor structures and for the 'know-how' of devices on their basis. The object of this work is to develop radiochemical neutron activation technique for analysis of high purity gallium. Irradiation of 0.1 g of gallium sample in neutron flux of 5·10 13 cm -2 s -1 for 5 hours will result in induced activity of more than 10 8 Bq, due to 72 Ga radionuclide, half-life of which is 14.1 hours. Therefore to perform instrumental NAA of gallium long period (10 day) cooling is required, and high sensitive determination of elements producing short- and long-lived radionuclides (T 1/2 72 Ga. We have studied the behavior of gallium in extraction-chromatographic system 'TBP-HCl'. The experiments have shown that higher factor of distribution (D) and capacity on gallium can be achieved when 'TBP-4M HCl' system is used. However more than 10 trace elements have high D and thus they cannot be separated from 72 Ga. To resolve the problem and increase the number of separated trace elements we have used preliminary satisfaction of chromatographic column with tellurium, which has D higher than the most of elements in 'TBP-4M HCl' system and thus suppresses extraction of elements. Distribution profile of gallium along the column and elution curve of 25 trace elements have been measured. Chemical yields of separated elements measured by using radiotracers are more than 93%. On the basis of the carried out researches

  2. Germanium field-effect transistor made from a high-purity substrate

    International Nuclear Information System (INIS)

    Hansen, W.L.; Goulding, F.S.; Haller, E.E.

    1978-11-01

    Field effect transistors have been fabricated on high-purity germanium substrates using low-temperature technology. The aim of this work is to preserve the low density of trapping centers in high-quality starting material by low-temperature ( 0 C) processing. The use of germanium promises to eliminate some of the traps which cause generation-recombination noise in silicon field-effect transistors (FET's) at low temperatures. Typically, the transconductance (g/sub m/) in the germanium FET's is 10 mA/V and the gate leakage can be less than 10 -12 A. Present devices exhibit a large 1/f noise component and most of this noise must be eliminated if they are to be competitive with silicon FET's commonly used in high-resolution nuclear spectrometers

  3. Facile synthesis of upconversion nanoparticles with high purity using lanthanide oleate compounds

    Science.gov (United States)

    Kang, Ning; Ai, Chao-Chao; Zhou, Ya-Ming; Wang, Zuo; Ren, Lei

    2018-02-01

    A novel strategy for preparing highly pure NaYF4-based upconversion nanoparticles (UCNPs) was developed using lanthanide oleate compounds [Ln(OA)3] as the precursor, denoted as the Ln–OA preparation method. Compared to the conventional solvothermal method for synthesizing UCNPs using lanthanide chloride compounds (LnCl3) as the precursor (denoted as the Ln–Cl method), the Ln–OA strategy exhibited the merits of high purity, reduced purification process and a uniform size in preparing core and core–shell UCNPs excited by a 980 or 808 nm near infrared (NIR) laser. This work sheds new insight on the preparation of UCNPs and promotes their application in biomedical fields.

  4. Catalytic enantioselective synthesis of chiral organic compounds of ultra-high purity of >99% ee.

    Science.gov (United States)

    Negishi, Ei-ichi; Xu, Shiqing

    2015-01-01

    Shortly after the discovery of Zr-catalyzed carboalumination of alkynes in 1978, we sought expansion of the scope of this reaction so as to develop its alkene version for catalytic asymmetric C-C bond formation, namely the ZACA (Zr-catalyzed asymmetric carboalumination of alkenes). However, this seemingly easy task proved to be quite challenging. The ZACA reaction was finally discovered in 1995 by suppressing three competitive side reactions, i.e., (i) cyclic carbometalation, (ii) β-H transfer hydrometalation, and (iii) alkene polymerization. The ZACA reaction has been used to significantly modernize and improve syntheses of various natural products including deoxypolypropionates and isoprenoids. This review focuses on our recent progress on the development of ZACA-lipase-catalyzed acetylation-transition metal-catalyzed cross-coupling processes for highly efficient and enantioselective syntheses of a wide range of chiral organic compounds with ultra-high enantiomeric purities.

  5. Preparative separation of high-purity cordycepin from Cordyceps militaris(L.) Link by high-speed countercurrent chromatography

    Science.gov (United States)

    Zhu, Licai; Liang, Yong; Lao, Deqiang; Zhang, Tianyou; Ito, Yoichiro

    2009-01-01

    A high-speed counter-current chromatography (HSCCC) technique in a preparative scale has been applied to separate and purify cordycepin from the extract of Cordyceps militaris(L.) Link by a one-step separation. A high efficiency of HSCCC separation was achieved on a two-phase solvent system of n-hexane–n-butanol–methanol–water (23:80:30:155, v/v/v/v) by eluting the lower mobile phase at a flow rate of 2 ml/min under a revolution speed of 850 rpm. HSCCC separation of 216.2 mg crude sample (contained cordycepin at 44.7% purity after 732 cation-exchange resin clean-up) yielded 64.8 mg cordycepin with purity of 98.9% and 91.7% recovery. Identification of the target compound was performed by UV, IR, MS, 1H NMR and 13C NMR. PMID:21643461

  6. Temperature dependence of luminescence for different surface flaws in high purity silica glass

    International Nuclear Information System (INIS)

    Fournier, J.; Grua, P.; Neauport, J.; Fargin, E.; Jubera, V.; Talaga, D.; Del Guerzo, A.; Raffy, G.; Jouannigot, S.

    2013-01-01

    In situ temperature dependence of the Photoluminescence under 325 nm irradiation is used to investigate defect populations existing in different surface flaws in high purity fused silica. Five photoluminescence bands peaking at 1.9, 2.1, 2.3, 2.63 and 3.11 eV have been detected in the spectral area ranging from 1.6 up to 3.6 eV. The Gaussian deconvolution of spectra allows dividing the five luminescence bands in two categories. The former corresponds to bands showing a significant intensity enhancement while temperature decreases; the latter corresponds to bands remaining insensitive to the temperature evolution. Such a behavior brings new information on defects involved in laser damage mechanism at 351 nm in nanosecond regime. (authors)

  7. A radioagent method for determination of traces of phosphorus in high-purity silicon

    International Nuclear Information System (INIS)

    Chen, P.Y.; Chen, J.S.; Sun, H.J.; Yang, M.H.

    1985-01-01

    The feasibility of the determination of phosphorus at the extreme trace levels in high-purity silicon by radioreagent method is explored. After silicon dissolution with hydrofluoric and nitric acids and matrix volatilization, 12-molybdophosphoric acid is formed by the addition of the reagent, sup(99)MoOsub(4)sup(2-), in nitric acid medium and then extracted into isobutyl acetate. By plotting the phosphorus content against the radioactivity of sup(99)Mo in the organic phase, a linear relationship persisting down to 5 ng is obtained. Special effort was made to eliminate the unreacted sup(99)MoOsub(4)sup(2-) reagent and the optimal control of phosphorus blank introduced through the multistage analytical procedure in order to ensure reliable determination of phosphorus at the ppb level. (author)

  8. Study of the intrisic mobility of dislocations in high purity niobium

    International Nuclear Information System (INIS)

    Lima, L.F.C.P. de

    1982-01-01

    The #betta# peak due to the double kink generation (DKG) along screw dislocations has been observed in high purity niobium. This peak appears at 270K (lHz) and is unstable. Some special thermomechanical treatments have been realized in order to develop and stabilize this peak. The evolution of the internal friction spectra has been studied as a function of these treatments. The screw dislocations network created by low temperature deformation is unstable and rearranges in two stages: a W stage (180K-240K) and a X stage (280K-350K). The transformation accomplished in the W stage and the effect of the #betta# peak stabilization treatment have been observed by transmission electron microscopy. (Author) [pt

  9. Influence of carbon and nitrogen on corrosion resistance of high purity Fe-50mass% Cr alloys

    International Nuclear Information System (INIS)

    Kato, Y.; Ujiro, T.; Satoh, S.; Yamato, K.; Abiko, K.

    1995-01-01

    High purity Fe-50mass%Cr alloys containing (C+N) in the range of 30 to 500 mass ppm were prepared and their corrosion resistance was investigated. Pitting potential in a 3.5mass%NaCl solution at 343K rose with reducing (C+N) content. Alloys containing (C+N) at less than 100 mass ppm did not sustain pitting corrosion. However, alloys containing 500 mass ppm (C+N) corroded severely in 6%FeCl 3 +1/20N HCl solutions. Heat treatment at 923K was recognized as influencing corrosion resistance due to precipitation of carbonitrides only in the case of the alloy containing 500 mass ppm (C+N). (orig.)

  10. High Purity Tungsten Spherical Particle Preparation From WC-Co Spent Hard Scrap

    Directory of Open Access Journals (Sweden)

    Han Chulwoong

    2015-06-01

    Full Text Available Tungsten carbide-cobalt hard metal scrap was recycled to obtain high purity spherical tungsten powder by a combined hydrometallurgy and physical metallurgy pathway. Selective leaching of tungsten element from hard metal scrap occurs at solid / liquid interface and therefore enlargement of effective surface area is advantageous. Linear oxidation behavior of Tungsten carbide-cobalt and the oxidized scrap is friable to be pulverized by milling process. In this regard, isothermally oxidized Tungsten carbide-cobalt hard metal scrap was mechanically broken into particles and then tungsten trioxide particle was recovered by hydrometallurgical method. Recovered tungsten trioxide was reduced to tungsten particle in a hydrogen environment. After that, tungsten particle was melted and solidified to make a spherical one by RF (Ratio Frequency thermal plasma process. Well spherical tungsten micro-particle was successfully obtained from spent scrap. In addition to the morphological change, thermal plasma process showed an advantage for the purification of feedstock particle.

  11. Some aspects of the metal purity in high strength Al-alloys

    International Nuclear Information System (INIS)

    Banizs, K.; Csernay-Balint, J.; Voeroes, G.

    1990-01-01

    The effect of Fe and Si on the properties of some high strength age-hardenable Al-alloys was investigated. It was found that a certain quantity (> 0.15 %) of Fe is advantageous to the formation of the cell-structure in the cast ingot both in the AlCuMg and AlZnMgCu alloys. An increased Fe-content causes a finer cell-structure. A higher Fe:Si ratio results in more homogeneous cell size distribution. Higher Si-content in the alloy decreases the favourable cast parameter range and increases the inclination to cracking of large diameter (> 270 mm) ingots. The reason of the correlation found between metal purity and mechanical properties is discussed

  12. Simulation for photon detection in spectrometric system of high purity (HPGe) using MCNPX code

    International Nuclear Information System (INIS)

    Correa, Guilherme Jorge de Souza

    2013-01-01

    The Brazilian National Commission of Nuclear Energy defines parameters for classification and management of radioactive waste in accordance with the activity of materials. The efficiency of a detection system is crucial to determine the real activity of a radioactive source. When it's possible, the system's calibration should be performed using a standard source. Unfortunately, there are only a few cases that it can be done this way, considering the difficulty of obtaining appropriate standard sources for each type of measurement. So, computer simulations can be performed to assist in calculating of the efficiency of the system and, consequently, also auxiliary the classification of radioactive waste. This study aims to model a high purity germanium (HPGe) detector with MCNPX code, approaching the spectral values computationally obtained of the values experimentally obtained for the photopeak of 137 Cs. The approach will be made through changes in outer dead layer of the germanium crystal modeled. (author)

  13. High-purity germanium detection system for the in vivo measurement of americium and plutonium

    International Nuclear Information System (INIS)

    Tyree, W.H.; Falk, R.B.; Wood, C.B.; Liskey, R.W.

    1976-01-01

    A high-purity germanium (HPGe) array, photon-counting system has been developed for the Rocky Flats Plant Body-Counter Medical Facility. The newly improved system provides exceptional resolutions of low-energy X-ray and gamma-ray spectra associated with the in vivo deposition of plutonium and americium. Described are the operational parameters of the system and some qualitative results illustrating detector performance for the photon emissions produced from the decay of plutonium and americium between energy ranges from 10 to 100 kiloelectron volts. Since large amounts of data are easily generated with the system, data storage, analysis, and computer software developments continue to be an essential ingredient for processing spectral data obtained from the detectors. Absence of quantitative data is intentional. The primary concern of the study was to evaluate the effects of the various physical and electronic operational parameters before adding those related entirely to a human subject

  14. Computers in the investigation of the impurity content of high-purity materials

    International Nuclear Information System (INIS)

    Makarov, Yu.B.; Yan'kov, S.V.

    1987-01-01

    The efficiency of the concept of data banks for the accumulation and processing of information is now generally acknowledged. In scientific investigations not only bibliographic but also factual data banks are becoming more and more prevalent. In this article, the authors consider the possibilities of providing a data bank on high-purity materials for the study of impurity contents. Also in this paper, the authors distinguish the following groups of problems that arise in the study of impurity composition and presents examples of their proposed solutions to these problems: the analysis of error and the determination of the most probably value of impurity concentration; the estimation of average properties of impurity composition with respect to groups of impurities and samples, and the forecast of the complete impurity composition

  15. Microtopography of bare peat: an objective classification from high-resolution topographic survey data

    Science.gov (United States)

    Smith, Mark; Warburton, Jeff

    2017-04-01

    Peatlands globally are at risk of degradation through increased susceptibility to erosion as a result of climate change. For peatland restoration practices to be designed efficiently and evaluated effectively, quantification of eroded peat volumes is required alongside an understanding of the processes responsible for their degradation. Owing to the unique material properties of peat, fine-scale microtopographic expressions of surface processes are especially pronounced and present a potentially rich source of geomorphological information; providing valuable insights into the stability and dominant surface process regimes. Bare peat is highly responsive to changing environmental forces acting at the near surface and characteristic microtopographies emerge in response to rainfall, surface wash, wind action and fluctuations in surface temperature (both drying and freezing). Spatial and temporal variations in surface roughness reflect contrasts in the physical properties of the peat and key erosion processes acting in combination. We present the first conceptual framework to rigorously describe bare peat microtopography and use Structure-from-Motion (SfM) surveys to quantify roughness for different peat surfaces. Through application of a survey-grade structured-light hand-held 3D imager (Mantis Vision F5-Short Range) which can represent sub-millimetre topographic variability in field conditions, we present the most reliable field validation of SfM at the plot scale (<1 m2). Peat microtopography is quantified using 26 roughness metrics that cover a range of surface features (including amplitude, spacing, hybrid, multi-scale and anisotropy parameters). SfM reconstructs peat microtopography effectively, although some smoothing is observed. Over 55 plots, the roughness of microtopographic types is quantified and an objective classification system derived from decision tree analysis. After training on 66% of the data, the decision tree correctly classified 85% of plots

  16. Quantification and modelling of 2,4-dinitrotoluene reduction with high-purity and cast iron.

    Science.gov (United States)

    Jafarpour, Behnam; Jafarpour, Benham; Imhoff, Paul T; Chiu, Pei C

    2005-01-01

    Cast iron has been used as a reactive material in permeable reactive barriers (PRBs) for site remediation. While reactions are generally believed to occur on the iron (oxide) surface, a recent study by [Oh, S.Y., Cha, D.K., Chiu, P.C., 2002a. Graphite-mediated reduction of 2,4-dinitrotoluene with elemental iron. Environ. Sci. Technol. 36 (10), 2178-2184] showed that graphite inclusions in cast iron can also serve as reaction sites for 2,4-dinitrotoluene (DNT). These authors also found that graphite-mediated reduction of DNT has a regioselectivity that is different from that for iron surface. In this study, we quantified the observations reported by Oh et al. and examined the role of graphite in cast iron through numerical modelling. Models containing one and two reaction sites were developed to evaluate the mass transfer, sorption and reaction rates for DNT reduction in batch systems containing high-purity and cast iron. Our simulations showed that the regioselectivity, defined as the ratio of the ortho- and para-nitro reduction rate constants, was 0.37+/-0.04 S.E. (S.E.=one estimated standard error) for iron surface and 3.59+/-0.76 S.E. for graphite surface. In the cast iron-water system, we estimated that at least 66+/-2% S.E. of the DNT was reduced on graphite surface, despite the low graphite content and the lower DNT reduction rate with graphite than with iron. Graphite played such an important role because of the rapid adsorption of DNT to graphite. In the batch experiments conducted by Oh et al., external mass transfer was not rate limiting. Surface reaction was the rate-limiting step for DNT reduction on the graphite surface in cast iron, whereas internal mass transfer and/or adsorption and surface reaction were important for high-purity iron.

  17. Assessment of radiochemical purity of [{sup 18}F]fludeoxyglucose by high pressure liquid chromatography (HPLC)

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Aline E.; Silva, Juliana B.; Silveira, Marina B.; Ferreira, Soraya Z., E-mail: radiofarmacoscdtn@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Unidade de Pesquisa e Producao de Radiofarmacos

    2011-07-01

    The quality control of [{sup 18}F]fludeoxyglucose ({sup 18}FDG) has received attention due to its increasing clinical use. Although the quality requirements of {sup 18}FDG are established in various pharmacopoeia, the suitability of all testing methods used should be verified under actual conditions of use and documented. The aim of this study was to develop a high pressure liquid chromatography (HPLC) method for radiochemical purity evaluation of {sup 18}FDG, based on pharmacopoeia references, and to verify its suitability for routine quality control in our centre. HPLC analysis was performed with an Agilent HPLC. {sup 18}FDG and impurities were separated on an anion-exchange column by isocratic elution with 0.1 M NaOH as the mobile phase. Detection was accomplished with refractive index and NaI (Tl) scintillation detectors. The flow rate of the mobile phase was set at 0.8 mL/min and the column temperature was kept at 35 deg C. Specificity, linearity, precision and robustness were assessed to verify if the method was adequate for its intended purpose. Retention time of {sup 18}FDG was not affected by the presence of other components of the formulation and a good peak resolution was achieved. The analytical curve of {sup 18}FDG was linear, with a correlation coefficient value of 0.9995. Intraday repeatable precision, reported as the relative standard deviation, was 0.11%. Analytical procedure remained unaffected by small variations in mobile phase flow rate. Results evidenced that HPLC is suitable for radiochemical purity evaluation of {sup 18}FDG, considering operational conditions of our laboratory. (author)

  18. Assessment of radiochemical purity of [18F]fludeoxyglucose by high pressure liquid chromatography (HPLC)

    International Nuclear Information System (INIS)

    Lacerda, Aline E.; Silva, Juliana B.; Silveira, Marina B.; Ferreira, Soraya Z.

    2011-01-01

    The quality control of [ 18 F]fludeoxyglucose ( 18 FDG) has received attention due to its increasing clinical use. Although the quality requirements of 18 FDG are established in various pharmacopoeia, the suitability of all testing methods used should be verified under actual conditions of use and documented. The aim of this study was to develop a high pressure liquid chromatography (HPLC) method for radiochemical purity evaluation of 18 FDG, based on pharmacopoeia references, and to verify its suitability for routine quality control in our centre. HPLC analysis was performed with an Agilent HPLC. 18 FDG and impurities were separated on an anion-exchange column by isocratic elution with 0.1 M NaOH as the mobile phase. Detection was accomplished with refractive index and NaI (Tl) scintillation detectors. The flow rate of the mobile phase was set at 0.8 mL/min and the column temperature was kept at 35 deg C. Specificity, linearity, precision and robustness were assessed to verify if the method was adequate for its intended purpose. Retention time of 18 FDG was not affected by the presence of other components of the formulation and a good peak resolution was achieved. The analytical curve of 18 FDG was linear, with a correlation coefficient value of 0.9995. Intraday repeatable precision, reported as the relative standard deviation, was 0.11%. Analytical procedure remained unaffected by small variations in mobile phase flow rate. Results evidenced that HPLC is suitable for radiochemical purity evaluation of 18 FDG, considering operational conditions of our laboratory. (author)

  19. The probability distribution of intergranular stress corrosion cracking life for sensitized 304 stainless steels in high temperature, high purity water

    International Nuclear Information System (INIS)

    Akashi, Masatsune; Kenjyo, Takao; Matsukura, Shinji; Kawamoto, Teruaki

    1984-01-01

    In order to discuss the probability distribution of intergranular stress corrsion carcking life for sensitized 304 stainless steels, a series of the creviced bent beem (CBB) and the uni-axial constant load tests were carried out in oxygenated high temperature, high purity water. The following concludions were resulted; (1) The initiation process of intergranular stress corrosion cracking has been assumed to be approximated by the Poisson stochastic process, based on the CBB test results. (2) The probability distribution of intergranular stress corrosion cracking life may consequently be approximated by the exponential probability distribution. (3) The experimental data could be fitted to the exponential probability distribution. (author)

  20. Characterization of high-purity niobium structures fabricated using the electron beam melting process

    Science.gov (United States)

    Terrazas Najera, Cesar Adrian

    Additive Manufacturing (AM) refers to the varied set of technologies utilized for the fabrication of complex 3D components from digital data in a layer-by-layer fashion. The use of these technologies promises to revolutionize the manufacturing industry. The electron beam melting (EBM) process has been utilized for the fabrication of fully dense near-net-shape components from various metallic materials. This process, catalogued as a powder bed fusion technology, consists of the deposition of thin layers (50 - 120microm) of metallic powder particles which are fused by the use of a high energy electron beam and has been commercialized by Swedish company Arcam AB. Superconducting radio frequency (SRF) cavities are key components that are used in linear accelerators and other light sources for studies of elemental physics. Currently, cavity fabrication is done by employing different forming processes including deep-drawing and spinning. In both of the latter techniques, a feedstock high-purity niobium sheet with a thickness ranging from 3-4 mm is mechanically deformed and shaped into the desired geometry. In this manner, half cavities are formed that are later joined by electron beam welding (EBW). The welding step causes variability in the shape of the cavity and can also introduce impurities at the surface of the weld interface. The processing route and the purity of niobium are also of utmost importance since the presence of impurities such as inclusions or defects can be detrimental for the SRF properties of cavities. The focus of this research was the use of the EBM process in the manufacture of high purity niobium parts with potential SRF applications. Reactor grade niobium was plasma atomized and used as the precursor material for fabrication using EBM. An Arcam A2 system was utilized for the fabrication. The system had all internal components of the fabrication chamber replaced and was cleaned to prevent contamination of niobium powder. A mini-vat, developed at

  1. Effect of temperature on corrosion of steels in high purity water

    International Nuclear Information System (INIS)

    Honda, Takashi; Kashimura, Eiji; Ohashi, Kenya; Furutani, Yasumasa; Ohsumi, Katsumi; Aizawa, Motohiro; Matsubayashi, Hideo.

    1987-01-01

    Effect of temperature on corrosion behavior of steels was evaluated in the range of 150 - 300 deg C in high purity water containing about 200 ppb oxygen. The exposure tests were carried out in actual and simulated reactor water of BWR plants. Through X-ray diffractometry, SIMS, XPS and chemical analyses, it was clarified that the chemical composition and morphology of oxide films formed on austenitic stainless steel changed above about 250 deg C. Chromium dissolved easily through corrosion above this temperature, and the oxide films primarily consisted of spinel type oxides containing high concentration of nickel. Further, as the protectivety of oxide films increased with temperature, the corrosion rate had a peak around 250 deg C after a long exposure period. A major phase of oxide films on carbon steel was magnetite in the whole temperature range. However, as the oxide films formed at high temperatures had very compact structures, the effect of temperature on the corrosion rate was similar to that observed on stainless steel. (author)

  2. Digitally synthesized high purity, high-voltage radio frequency drive electronics for mass spectrometry

    Science.gov (United States)

    Schaefer, R. T.; MacAskill, J. A.; Mojarradi, M.; Chutjian, A.; Darrach, M. R.; Madzunkov, S. M.; Shortt, B. J.

    2008-09-01

    Reported herein is development of a quadrupole mass spectrometer controller (MSC) with integrated radio frequency (rf) power supply and mass spectrometer drive electronics. Advances have been made in terms of the physical size and power consumption of the MSC, while simultaneously making improvements in frequency stability, total harmonic distortion, and spectral purity. The rf power supply portion of the MSC is based on a series-resonant LC tank, where the capacitive load is the mass spectrometer itself, and the inductor is a solenoid or toroid, with various core materials. The MSC drive electronics is based on a field programmable gate array (FPGA), with serial peripheral interface for analog-to-digital and digital-to-analog converter support, and RS232/RS422 communications interfaces. The MSC offers spectral quality comparable to, or exceeding, that of conventional rf power supplies used in commercially available mass spectrometers; and as well an inherent flexibility, via the FPGA implementation, for a variety of tasks that includes proportional-integral derivative closed-loop feedback and control of rf, rf amplitude, and mass spectrometer sensitivity. Also provided are dc offsets and resonant dipole excitation for mass selective accumulation in applications involving quadrupole ion traps; rf phase locking and phase shifting for external loading of a quadrupole ion trap; and multichannel scaling of acquired mass spectra. The functionality of the MSC is task specific, and is easily modified by simply loading FPGA registers or reprogramming FPGA firmware.

  3. Digitally synthesized high purity, high-voltage radio frequency drive electronics for mass spectrometry.

    Science.gov (United States)

    Schaefer, R T; MacAskill, J A; Mojarradi, M; Chutjian, A; Darrach, M R; Madzunkov, S M; Shortt, B J

    2008-09-01

    Reported herein is development of a quadrupole mass spectrometer controller (MSC) with integrated radio frequency (rf) power supply and mass spectrometer drive electronics. Advances have been made in terms of the physical size and power consumption of the MSC, while simultaneously making improvements in frequency stability, total harmonic distortion, and spectral purity. The rf power supply portion of the MSC is based on a series-resonant LC tank, where the capacitive load is the mass spectrometer itself, and the inductor is a solenoid or toroid, with various core materials. The MSC drive electronics is based on a field programmable gate array (FPGA), with serial peripheral interface for analog-to-digital and digital-to-analog converter support, and RS232/RS422 communications interfaces. The MSC offers spectral quality comparable to, or exceeding, that of conventional rf power supplies used in commercially available mass spectrometers; and as well an inherent flexibility, via the FPGA implementation, for a variety of tasks that includes proportional-integral derivative closed-loop feedback and control of rf, rf amplitude, and mass spectrometer sensitivity. Also provided are dc offsets and resonant dipole excitation for mass selective accumulation in applications involving quadrupole ion traps; rf phase locking and phase shifting for external loading of a quadrupole ion trap; and multichannel scaling of acquired mass spectra. The functionality of the MSC is task specific, and is easily modified by simply loading FPGA registers or reprogramming FPGA firmware.

  4. Characteristics of high-purity Teflon vial for 14C measurement in old tree rings

    International Nuclear Information System (INIS)

    Sakurai, H.; Saswaki, Y.; Matsumoto, T.; Aoki, T.; Kato, W.; Gandou, T.; Gunji, S.; Tokanai, F.

    2003-01-01

    14 C concentration in single-year tree rings of an old cedar of ca. 2500 years ago is measured to investigate the 11-yr periodicity of solar activity. Our highly accurate 14 C measuring system is composed of a benzene synthesizer capable of producing a large quantity (10 g) of benzene and a Quantulus 1220 TM liquid scintillation counting system. The accuracy is less than 0.2% for measurements of 14 C concentration. The benzene sample is contained in a high-purity Teflon/copper-counting vial (20 ml) manufactured by Wallac Oy Company. We found a vial with an irregular copper cap for the measurements of 11 tree rings. The behavior of the vial with the irregular cap was investigated. The Teflon sheet inside the cap plays an important role in achieving stable measurement. The rate of volatilization of the benzene was less than 0.35 mg/day for vials with ordinary caps. This results in the volatilization rate of 0.003% for 10.5 g of benzene and hence guarantees measurement at an accuracy of 0.2% for 70 days

  5. Production of Ultrafine, High-purity Ceramic Powders Using the US Bureau of Mines Developed Turbomill

    Science.gov (United States)

    Hoyer, Jesse L.

    1993-01-01

    Turbomilling, an innovative grinding technology developed by the U.S. Bureau of Mines in the early 1960's for delaminating filler-grade kaolinitic clays, has been expanded into the areas of particle size reduction, material mixing, and process reaction kinetics. The turbomill, originally called an attrition grinder, has been used for particle size reduction of many minerals, including natural and synthetic mica, pyrophyllite, talc, and marble. In recent years, an all-polymer version of the turbomill has been used to produce ultrafine, high-purity, advanced ceramic powders such as SiC, Si3N4, TiB2, and ZrO2. In addition to particle size reduction, the turbomill has been used to produce intimate mixtures of high surface area powders and whiskers. Raw materials, TiN, AlN, and Al2O3, used to produce a titanium nitride/aluminum oxynitride (TiN/AlON) composite, were mixed in the turbomill, resulting in strength increases over samples prepared by dry ball milling. Using the turbomill as a leach vessel, it was found that 90.4 pct of the copper was extracted from the chalcopyrite during a 4-hour leach test in ferric sulfate versus conventional processing which involves either roasting of the ore for Cu recovery or leaching of the ore for several days.

  6. Hydrogen in-situ refining method for preparing high purity gadolinium

    International Nuclear Information System (INIS)

    Li, Guoling; Li, Li; Fu, Kai; Wang, Chongyun; Zheng, Jie; Xu, Li; Tian, Wenhuai; Li, Xingguo

    2015-01-01

    The removal of non-metallic impurities, especially oxygen and nitrogen, from the rare-earth metal gadolinium (Gd) is challenging, due to their strong affinity to Gd metal. Herein we present an effective approach to prepare high purity Gd via a novel hydrogen in-situ refining method. The final concentrations of oxygen and nitrogen could be reduced to 30 and 19 mass ppm, respectively. The changes of lattice parameters were derived from XRD; enthalpy values and gaseous speciation associated with the gas–solid physiochemical reactions were determined through a combination of DSC/MS measurements and thermodynamic calculations. The results show that oxygen and nitrogen can be efficiently removed by degassing Gd with dissolved hydrogen. The underlying mechanism for the refinement is discussed systematically in this paper. - Highlights: • Hydrogen can shuttle gadolinium freely at high temperature. • The concentration of O and N dropped to 30 ppm and 19 ppm, respectively. • The hydrogen content could finally decrease to 17 ppm. • Hydrogen, water and ammonia signals can be detected successfully. • This method is environment friendly and no other recontaminations

  7. Hydrogen in-situ refining method for preparing high purity gadolinium

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guoling [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Li, Li [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Fu, Kai [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Wang, Chongyun [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Zheng, Jie [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Xu, Li [State Grid Smart Grid Research Institute, Future Science& Technology Park, Changping, Beijing 102211 (China); Tian, Wenhuai [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Li, Xingguo, E-mail: xgli@pku.edu.cn [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)

    2015-11-05

    The removal of non-metallic impurities, especially oxygen and nitrogen, from the rare-earth metal gadolinium (Gd) is challenging, due to their strong affinity to Gd metal. Herein we present an effective approach to prepare high purity Gd via a novel hydrogen in-situ refining method. The final concentrations of oxygen and nitrogen could be reduced to 30 and 19 mass ppm, respectively. The changes of lattice parameters were derived from XRD; enthalpy values and gaseous speciation associated with the gas–solid physiochemical reactions were determined through a combination of DSC/MS measurements and thermodynamic calculations. The results show that oxygen and nitrogen can be efficiently removed by degassing Gd with dissolved hydrogen. The underlying mechanism for the refinement is discussed systematically in this paper. - Highlights: • Hydrogen can shuttle gadolinium freely at high temperature. • The concentration of O and N dropped to 30 ppm and 19 ppm, respectively. • The hydrogen content could finally decrease to 17 ppm. • Hydrogen, water and ammonia signals can be detected successfully. • This method is environment friendly and no other recontaminations.

  8. Electron microscopy and krypton adsorption characterization of high-purity MgO powder

    International Nuclear Information System (INIS)

    Bretz, M.; Shastri, A.G.; Schwank, J.

    1986-01-01

    A promising method for the preparation of sizeable quantities of structurally well-defined, high-purity MgO powder is reported. The morphology and surface uniformity of the powder is comparable to that of MgO smokes but with narrow size distribution of particles. Sample characterization of these oxide powders is accomplished by combining structural TEM/STEM examination with krypton gas adsorption isotherms. The latter technique is sensitive to the presence of surface hydroxyl groups and of surface roughness on an atomic scale. High-resolution TEM indicates a perfect cubic morphology, intra-crystallite orientation, and dendritic sintering of cubes. In the STEM mode sharp convergent beam electron diffraction patterns are obtained, and in thick specimen regions Kikuchi lines appear, indicating the absence of crystal defects. After prolonged outgassing to remove surface hydroxyl groups, a krypton adsorption isotherm contains a near vertical submonolayer riser and second layer step along with partial wetting features near saturation. These near-ideal dendritic ceramic powders, therefore, provide a research bridge between single crystal surface studies and large-scale powder technology

  9. Modelling of hydrogen permeability of membranes for high-purity hydrogen production

    Science.gov (United States)

    Zaika, Yury V.; Rodchenkova, Natalia I.

    2017-11-01

    High-purity hydrogen is required for clean energy and a variety of chemical technology processes. Different alloys, which may be well-suited for use in gas-separation plants, were investigated by measuring specific hydrogen permeability. One had to estimate the parameters of diffusion and sorption to numerically model the different scenarios and experimental conditions of the material usage (including extreme ones), and identify the limiting factors. This paper presents a nonlinear mathematical model taking into account the dynamics of sorption-desorption processes and reversible capture of diffusing hydrogen by inhomogeneity of the material’s structure, and also modification of the model when the transport rate is high. The results of numerical modelling allow to obtain information about output data sensitivity with respect to variations of the material’s hydrogen permeability parameters. Furthermore, it is possible to analyze the dynamics of concentrations and fluxes that cannot be measured directly. Experimental data for Ta77Nb23 and V85Ni15 alloys were used to test the model. This work is supported by the Russian Foundation for Basic Research (Project No. 15-01-00744).

  10. Electron spin resonance spectroscopy of high purity crystals at millikelvin temperatures

    Science.gov (United States)

    Farr, Warrick G.; Creedon, Daniel L.; Goryachev, Maxim; Benmessai, Karim; Tobar, Michael E.

    2013-12-01

    Progress in the emerging field of engineered quantum systems requires the development of devices that can act as quantum memories. The realisation of such devices by doping solid state cavities with paramagnetic ions imposes a trade-off between ion concentration and cavity coherence time. Here, we investigate an alternative approach involving interactions between photons and naturally occurring impurity ions in ultra-pure crystalline microwave cavities exhibiting exceptionally high quality factors. We implement a hybrid Whispering Gallery/Electron Spin Resonance method to perform rigorous spectroscopy of an undoped single-crystal sapphire resonator over the frequency range 8{19 GHz, and at external applied DC magnetic fields up to 0.9 T. Measurements of a high purity sapphire cooled close to 100 mK reveal the presence of Fe3+, Cr3+, and V2+ impurities. A host of electron transitions are measured and identified, including the two-photon classically forbidden quadrupole transition (Δms = 2) for Fe3+, as well as hyperfine transitions of V2+.

  11. Determination of cadmium oxide in and on the surface of high purity cadmium metal

    International Nuclear Information System (INIS)

    Kiba, Toshiyasu; Matsumoto, Ken; Shimizu, Genji

    1975-01-01

    In a 100 ml separating funnel were added 50 ml of 1 M ammonium chloride-aqueous ammonia buffer solution(pH 10) and 2.5 ml mercury; after passing nitrogen gas sufficiently to remove oxygen from the vessel and also from the aqueous solution, several pieces of cadmium metal of high purity were put into the vessel. The content was shaken vigorously; the metal went into mercury forming cadmium-amalgam, while the cadmium oxide dissolved itself in the aqueous solution to form cadmium tetrammine complex cations. After Removal of mercury from the funnel, the solution was submitted to the determination of cadmium dissolved in it by means of the atomic absorption spectrophotometry of the EDTA titration. By the above procedure a minute amount of cadmium oxide could be determined precisely with high reproducibility. The critical experiments were also done to clarify the behaviors of cadmium metal and cadmium oxide in this separation process for the purpose of establishing a suitable procedure. (auth.)

  12. A green preparation of Mn-based product with high purity from low-grade rhodochrosite

    Science.gov (United States)

    Lian, F.; Ma, L.; Chenli, Z.; Mao, L.

    2018-01-01

    The low-grade rhodochrosite, the main resources for exploitation and applications in China, contains multiple elements such as iron, silicon, calcium and magnesium. So the conventional preparation of manganese sulphate and manganese oxide with high purity from electrolytic product is characterized by long production-cycle, high-resource input and high-pollution discharge. In our work, a sustainable preparation approach of high pure MnSO4 solution and Mn3O4 was studied by employing low-grade rhodochrosite (13.86%) as raw material. The repeated leaching of rhodochrosite with sulphuric acid was proposed in view of the same ion effect, in order to improve the solubility of Mn2+ and inhibit the dissolution of the impurities Ca2+ and Mg2+. With the aid of theoretical calculation, BaF2 was chosen to remove Ca2+ and Mg2+ completely in the process of purifying. The results showed that the impurities such as Ca2+, Mg2+, Na+ were decreased to less than 20ppm, and the Ni- and Fe- impurities were decreased to less than 1ppm, which meets the standards of high pure reagent for energy and electronic materials. The extraction ratio and the recovery ratio of manganese reached 94.3% and 92.7%, respectively. Moreover, the high pure Mn3O4 was one-step synthesized via the oxidation of MnSO4 solution with the ratios of OH-/Mn2+=2 and Mn2+/H2O2=1.03, and the recovery rate of manganese reaches 99%.

  13. Leakage current in high-purity germanium detectors with amorphous semiconductor contacts

    Science.gov (United States)

    Looker, Q.; Amman, M.; Vetter, K.

    2015-03-01

    Amorphous semiconductor electrical contacts on high-purity Ge radiation detectors have become a valuable technology because they are simple to fabricate, result in thin dead layers, block both electron and hole injection, and can readily be finely segmented as needed for applications requiring imaging or particle tracking. Though significant numbers of detectors have been successfully produced for a variety of applications using the amorphous semiconductor contact technology, there remains a need to better understand the dependence of performance characteristics, particularly leakage current, on the fabrication process parameters so that the performance can be better optimized. To this end, we have performed a systematic study of leakage current on RF-sputter-deposited amorphous-Ge (a-Ge) and amorphous-Si (a-Si) contacts as a function of process and operational parameters including sputter gas pressure and composition, number of detector temperature cycles, and time spent at room temperature. The study focused primarily on the current resulting from electron injection at the contact. Significant findings from the study include that a-Si produces lower electron injection than a-Ge, the time the detector spends at room temperature rather than the number of temperature cycles experienced by the detector is the primary factor associated with leakage current change when the detector is warmed, and the time stability of the a-Ge contact depends on the sputter gas pressure with a higher pressure producing more stable characteristics.

  14. GELATIO: a general framework for modular digital analysis of high-purity Ge detector signals

    International Nuclear Information System (INIS)

    Agostini, M; Pandola, L; Zavarise, P; Volynets, O

    2011-01-01

    GELATIO is a new software framework for advanced data analysis and digital signal processing developed for the GERDA neutrinoless double beta decay experiment. The framework is tailored to handle the full analysis flow of signals recorded by high purity Ge detectors and photo-multipliers from the veto counters. It is designed to support a multi-channel modular and flexible analysis, widely customizable by the user either via human-readable initialization files or via a graphical interface. The framework organizes the data into a multi-level structure, from the raw data up to the condensed analysis parameters, and includes tools and utilities to handle the data stream between the different levels. GELATIO is implemented in C++. It relies upon ROOT and its extension TAM, which provides compatibility with PROOF, enabling the software to run in parallel on clusters of computers or many-core machines. It was tested on different platforms and benchmarked in several GERDA-related applications. A stable version is presently available for the GERDA Collaboration and it is used to provide the reference analysis of the experiment data.

  15. MIS High-Purity Plutonium Oxide Metal Oxidation Product TS707001 (SSR123): Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Veirs, Douglas Kirk [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stroud, Mary Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Berg, John M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Narlesky, Joshua Edward [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Worl, Laura Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Martinez, Max A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carillo, Alex [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-09

    A high-purity plutonium dioxide material from the Material Identification and Surveillance (MIS) Program inventory has been studied with regard to gas generation and corrosion in a storage environment. Sample TS707001 represents process plutonium oxides from several metal oxidation operations as well as impure and scrap plutonium from Hanford that are currently stored in 3013 containers. After calcination to 950°C, the material contained 86.98% plutonium with no major impurities. This study followed over time, the gas pressure of a sample with nominally 0.5 wt% water in a sealed container with an internal volume scaled to 1/500th of the volume of a 3013 container. Gas compositions were measured periodically over a six year period. The maximum observed gas pressure was 138 kPa. The increase over the initial pressure of 80 kPa was primarily due to generation of nitrogen and carbon dioxide gas in the first six months. Hydrogen and oxygen were minor components of the headspace gas. At the completion of the study, the internal components of the sealed container showed signs of corrosion, including pitting.

  16. Precise coulometric titration of uranium in a high-purity uranium metal and in uranium compounds

    International Nuclear Information System (INIS)

    Tanaka, Tatsuhiko; Yoshimori, Takayoshi

    1975-01-01

    Uranium in uranyl nitrate, uranium trioxide and a high-purity uranium metal was assayed by the coulometric titration with biamperometric end-point detection. Uranium (VI) was reduced to uranium (IV) by solid bismuth amalgam in 5M sulfuric acid solution. The reduced uranium was reoxidized to uranium (VI) with a large excess of ferric ion at a room temperature, and the ferrous ion produced was titrated with the electrogenerated manganese(III) fluoride. In the analyses of uranium nitrate and uranium trioxide, the results were precise enough when the error from uncertainty in water content in the samples was considered. The standard sample of pure uranium metal (JAERI-U4) was assayed by the proposed method. The sample was cut into small chips of about 0.2g. Oxides on the metal surface were removed by the procedure shown by National Bureau of Standards just before weighing. The mean assay value of eleven determinations corrected for 3ppm of iron was (99.998+-0.012) % (the 95% confidence interval for the mean), with a standard deviation of 0.018%. The proposed coulometric method is simple and permits accurate and precise determination of uranium which is matrix constituent in a sample. (auth.)

  17. Water containing deuterium electrolysis to obtain gaseous hydrogen isotope in a high state of purity

    International Nuclear Information System (INIS)

    Bellanger, Gilbert

    1992-01-01

    In this paper, the basic concept is to prepare hydrogen in a high state of purity by electrolysing water using a palladium cathode. During electrolysis, hydrogen is at first adsorbed at the palladium surface, and next it diffuses through it till opposite face of its entry where it is desorbed; thus permitting to regain it in a very pure state for storage. The method can be used from water containing deuterium. To improve hydrogen adsorption, surface effect of palladium must be studied. It was found that heat treatment of palladium improved the hydrogen permeation flux. The diffusivity of hydrogen is controlled by Fick and Sieverts equations in which temperature has a significant influence on permeation rates. Anyway, hydrogen desorption does not cause any difficulty. In a second part, we have studied the isotopic separation factor using water containing deuterium. We remarked in fact that it depends on current density, overpotential, diffusivity of hydrogen and deuterium and isotopic composition of electrolyte as expected. In the last part, we realized an original electrolysis model in a glove-box in which are taken into account the results given before and also the technology components employed in processes involving the use of tritium. (author) [fr

  18. Abridged acid-base wet-milling synthesis of high purity hydroyapatite

    Directory of Open Access Journals (Sweden)

    Sandi Carolina Ruiz-Mendoza

    2008-06-01

    Full Text Available There is a plethora of routes to produce hydroxyapatite(HA and in general calcium phosphates(CP but production usually leads to a mixture of several phases. Besides ionic contamination, most of these methods are cumbersome, restricted to small volumes of product and require a lot of thermal energy. The acid-base route eliminates foreign ions or additives and its only byproduct is water. Heterogeneous reaction drawback is that solid reactants do not easily come in contact with each other and therefore addition and stirring times become very lengthy and still the product is a mixture. The synthesis started from calcium hydroxide and phosphoric acid (PA. Ball milling was used to favor kinetics and stoichiometry. Six sets of PA addition, paddle stirring and ball milling times were used. Products were evaluated by X ray diffraction (XRD, Fourier Transform Infrared (FTIR, scanning electron microscopy (SEM, X ray fluorescence (XRF and Ca/P ratio. Chemical analysis for calcium proceeded through oxalate precipitate and phosphorus by the phosphomolibdate technique. A set of conditions yielding high purity HA was established.

  19. Numerical Simulation and Experimental Investigation on Multi-direction Forging Behaviors of High Purity Aluminum

    Directory of Open Access Journals (Sweden)

    ZHU Qing-feng

    2017-04-01

    Full Text Available The effect of forging pass on the deformation structure of high purity aluminum at room temperature during multi-direction forging process was investigated by experiment. The multi-direction forging process was analyzed by using software of DEFORM-3D. The results show that an X-shape fine grain zone (in the center of the sample and four coarse grain zones (near the end surface of the sample are initially formed on the cross section of the sample as forging passes increase to 3. With a further increasing the passes to 9, this X-shape zone tends to spread the whole sample. However, the grain difference between the coarse grain zone and fine grain zone still exists on the sample forged by 9 passes. Limitation in the structural refinement is observed in the center of the sample with the increment of equivalent strain. The grains size in the center is refined to a certain size (about 70μm as equivalent strain reaches 2.5, and no further grain refinement in the center with increasing the equivalent strain to 6.0. However, the grains size in the area near the surface is continuously refined with the increasing the equivalent strain to 4.0. This indicates that the local deformation state and the equivalent strain are two important factors that affect the grain size.

  20. Stress corrosion of very high purity stainless steels in alkaline media

    International Nuclear Information System (INIS)

    Hechmat-Dehcordi, Ebrahim

    1981-01-01

    This research thesis reports the study of stress corrosion resistance of stainless steels in caustic environments. It notably concerns the electronuclear industrial sector, the production of soda by electrolysis, and the preparation of hydrogen as energy vector. After a presentation of the experimental conditions, the author highlights the influence of purity on stress corrosion cracking of 20Cr-25Ni-type austenitic alloys. The specific action of a high number of addition metallic and non-metallic elements has been studied. Stress corrosion tests have been also performed in autoclave on austeno-ferritic (21 to 25 pc Cr - 6 to 10 pc Ni) as well as ferritic (26 pc Cr) grades. The author reports the study of electrochemical properties of stainless steel in soda by means of potentiostatic techniques with an application of Pourbaix thermodynamic equilibrium diagrams, and the study of the chemical composition of passivation thin layers by Auger spectroscopy. He more particularly studies the influence of electrode potential and of some addition elements on the chemical characteristics of oxides developed at the surface of austenite. Then, the author tries to establish correlations between strain hardening microstructure of the various steels and their sensitivity to stress corrosion [fr

  1. Synthesis of high purity monoglycerides from crude glycerol and palm stearin

    Directory of Open Access Journals (Sweden)

    Pakamas Chetpattananondh

    2008-07-01

    Full Text Available The optimum conditions for the glycerolysis of palm stearin and crude glycerol derived from biodiesel process werefound to be a reaction temperature of 200oC with a molar ratio of crude glycerol to palm stearin of 2.5:1, and a reaction timeof 20 minutes. The yield and purity of monoglycerides obtained under these conditions was satisfactory as compared withthe glycerolysis of pure glycerol. To increase the purity of monoglycerides a two-step process, removal of residual glyceroland crystallization, was proposed instead of either vacuum or molecular distillation. Residual glycerol was removed byadding hydrochloric acid followed by washing with hot water. Optimum conditions for crystallization were achieved byusing isooctane as a solvent and a turbine impeller speed of 200 rpm at a crystallization temperature of 35oC. A purity notexceeding 99 percent of monoglycerides was obtained with monopalmitin as the major product.

  2. Melt-drop technique for the production of high-purity metal powder

    International Nuclear Information System (INIS)

    Aldinger, F.; Linck, E.; Claussen, N.

    1977-01-01

    The production of high-purity powders of metals and alloys such as beryllium, titanium alloys, or superalloys is a problem. Oxidation of these materials cannot be avoided. Oxidation occurs in inert gases and even in reducing atmospheres when any gas impurities are present. Therefore, the powder production of these materials has to be performed either in high vacuum or at least in a static atmosphere of inert gas purified immediately before coming into contact with the disintegrating material. These requirements are very well met by the melt-drop technique presented in this paper, especially for coarse powders which must not necessarily be cold-workable. This is true, for example, for superalloys where high-temperature applications require large grain sizes; or in titanium alloys because the final microstructure will be achieved by a thermomechanical treatment. In the case of beryllium and beryllium alloys, where grain sizes <5 μm are desired, further milling is necessary. But the melt-drop technique offers a simple and clean method directly from the purifying process of vacuum melting. In melt-drop processes a liquid metal flows through a nozzle at the bottom of a crucible or the melt is just poured through a sieve. The theory of disintegration of a liquid jet into droplets, dates back to the 19th century. More recent investigations attempted to produce uniformly sized droplets by applying a capillary wave of given wave length to the jet. But this has been done only with non-metallic materials. Evidence is presented to prove the theory and show that this concept is applicable to the production of metal powders with controlled particle size

  3. Manufacture and study of very high purity P-type Silicium nuclear detectors

    International Nuclear Information System (INIS)

    Rahab, H.

    1986-04-01

    The purpose of this study is the realization of P-type silicon detectors of very high resistivity. The well-known process of Li ion drifting compensates for the acceptor impurities in the P-type Si of low resistivity used for the manufacturing of Si(Li) detector becomes useless. The last (Si(Li)) present a problem of utilization and storage at low temperature. The obtainment of silicon monocrystals having a resistivity reaching 130.000 Ω cm allows to use them directly in detection of nuclear radiations without compensating them with lithium. In order to familiarise with the techniques of detectors manufacturing in general, we have realized Si(Li) detectors. Afterwards we began the research itself by a study and realization of a great number and different types of detectors from P-type silicon having a resistivity varying from 40.000 to 100.000 Ω cm. The surface barrier detectors (SBD) elaborated after an investigation of different chemical treatments present electrical characteristics and dead layer better than Si(Li) detectors at time t=0. However they present a stability problem. A more profound investigation has to be undertaken in the future to improve the contacts and the surface treatment which are the principal causes of this instability. PIN type detectors made by implantation technique gave way to very promising results in nuclear detection. The resolutions which are obtained on the peaks of energy above 20 KeV, are much comparable to those obtained with the Si(Li) detectors. (For example, we have obtained a resolution of 540 eV on the peak of 59,6 KeV for 241 Am with a high purity Si(p) detector implanted B-AS). However to be used in the low energies field (20 KeV) it is necessary to diminish the dead layer. For this purpose, and implantation at lower energies than those used must be envisaged

  4. Metallic oxide nano-clusters synthesis by ion implantation in high purity Fe10Cr alloy

    International Nuclear Information System (INIS)

    Zheng, Ce

    2015-01-01

    ODS (Oxide Dispersed Strengthened) steels, which are reinforced with metal dispersions of nano-oxides (based on Y, Ti and O elements), are promising materials for future nuclear reactors. The detailed understanding of the mechanisms involved in the precipitation of these nano-oxides would improve manufacturing and mechanical properties of these ODS steels, with a strong economic impact for their industrialization. To experimentally study these mechanisms, an analytical approach by ion implantation is used, to control various parameters of synthesis of these precipitates as the temperature and concentration. This study demonstrated the feasibility of this method and concerned the behaviour of alloys models (based on aluminium oxide) under thermal annealing. High purity Fe-10Cr alloys were implanted with Al and O ions at room temperature. Transmission electron microscopy observations showed that the nano-oxides appear in the Fe-10Cr matrix upon ion implantation at room temperature without subsequent annealing. The mobility of implanted elements is caused by the defects created during ion implantation, allowing the nucleation of these nanoparticles, of a few nm in diameter. These nanoparticles are composed of aluminium and oxygen, and also chromium. The high-resolution experiments show that their crystallographic structure is that of a non-equilibrium compound of aluminium oxide (cubic γ-Al 2 O 3 type). The heat treatment performed after implantation induces the growth of the nano-sized oxides, and a phase change that tends to balance to the equilibrium structure (hexagonal α-Al 2 O 3 type). These results on model alloys are fully applicable to industrial materials: indeed ion implantation reproduces the conditions of milling and heat treatments are at equivalent temperatures to those of thermo-mechanical treatments. A mechanism involving the precipitation of nano-oxide dispersed in ODS alloys is proposed in this manuscript based on the obtained experimental results

  5. Dielectric Performance of a High Purity HTCC Alumina at High Temperatures - a Comparison Study with Other Polycrystalline Alumina

    Science.gov (United States)

    Chen, Liangyu

    2014-01-01

    A very high purity (99.99+%) high temperature co-fired ceramic (HTCC) alumina has recently become commercially available. The raw material of this HTCC alumina is very different from conventional HTCC alumina, and more importantly there is no glass additive in this alumina material for co-firing processing. Previously, selected HTCC and LTCC (low temperature co-fired ceramic) alumina materials were evaluated at high temperatures as dielectric and compared to a regularly sintered 96% polycrystalline alumina (96% Al2O3), where 96% alumina was used as the benchmark. A prototype packaging system based on regular 96% alumina with Au thickfilm metallization successfully facilitated long term testing of high temperature silicon carbide (SiC) electronic devices for over 10,000 hours at 500 C. In order to evaluate this new high purity HTCC alumina for possible high temperature packaging applications, the dielectric properties of this HTCC alumina substrate were measured and compared with those of 96% alumina and a previously tested LTCC alumina from room temperature to 550 C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. A parallel-plate capacitive device with dielectric of the HTCC alumina and precious metal electrodes were used for measurements of the dielectric constant and dielectric loss of the co-fired alumina material in the temperature and frequency ranges. The capacitance and AC parallel conductance of the capacitive device were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of the HTCC alumina substrate are presented and compared to those of 96% alumina and a selected LTCC alumina. Other technical advantages of this new co-fired material for possible high packaging applications are also discussed.

  6. Cross Purposes: Love and Purity at a Puerto Rican Protestant High School

    Science.gov (United States)

    Seale-Collazo, James

    2013-01-01

    A "native" Christian ethnographer finds religious education at this church-sponsored school to pursue two distinct, and occasionally conflicting, curricula: "love" and "purity." The curriculum of love draws on what Turner called liminality and communitas in an effort to promote spiritual "encounters with…

  7. Evaluation of Prebiotic Effects of High-Purity Galactooligosaccharides in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Ki Bae Hong

    2016-01-01

    Full Text Available Galactooligosaccharides (GOS are an important class of dietary prebiotics that exert beneficial effects on intestinal microbiota and gut barrier function. In this study, high-purity GOS (HP-GOS were investigated in vitro and in vivo and confirmed as prebiotic ingredients in rat diet. HP-GOS were successfully produced using a two-step process, enzymatic hydrolysis and fermentation by yeast. They were found to serve as a good substrate and carbon source for supporting the growth of probiotic bacteria more effectively than other commercial GOS. Following administration of 1 % (by mass of HP-GOS to rats, the growth of Bifidobacterium bifidum and B. longum in the gut increased most rapidly up to 12 h, and thereafter the increase was slow. Therefore, 1 % HP-GOS was found to be acceptable for the growth of probiotic bacteria. Groups of animals that were orally administered HP-GOS and bifidobacteria during the study, and the group administered HP-GOS during the 2nd (days 13–15 and 4th (days 28–30 period of the study had significantly (p<0.05 higher numbers of bifidobacteria in faeces than groups receiving a single dose of bifidobacteria. HP-GOS affected the expression of genes encoding glucagon-like peptide-1 (GLP-1 and peptide YY (PYY. There was a significant upregulation of GLP-1 and PYY mRNA with HP-GOS and bifidobacteria intake. We propose that the prebiotic properties of HP-GOS are potentially valuable for the production of functional foods for human consumption.

  8. Diffusion bonding and brazing of high purity copper for linear collider accelerator structures

    Directory of Open Access Journals (Sweden)

    J. W. Elmer

    2001-05-01

    Full Text Available Diffusion bonding and brazing of high purity copper were investigated to develop procedures for joining precision machined copper components for the Next Linear Collider (NLC. Diffusion bonds were made over a range of temperatures from 400 °C to 1000 °C, under two different loading conditions [3.45 kPa (0.5 psi and 3.45 MPa (500 psi], and on two different diamond machined surface finishes. Brazes were made using pure silver, pure gold, and gold-nickel alloys, and different heating rates produced by both radiation and induction heating. Braze materials were applied by both physical vapor deposition (PVD and conventional braze alloy shims. Results of the diffusion bonding experiments showed that bond strengths very near that of the copper base metal could be made at bonding temperatures of 700 °C or higher at 3.45 MPa bonding pressure. At lower temperatures, only partial strength diffusion bonds could be made. At low bonding pressures (3.45 kPa, full strength bonds were made at temperatures of 800 °C and higher, while no bonding (zero strength was observed at temperatures of 700 °C and lower. Observations of the fracture surfaces of the diffusion bonded samples showed the effects of surface finish on the bonding mechanism. These observations clearly indicate that bonding began by point asperity contact, and flatter surfaces resulted in a higher percentage of bonded area under similar bonding conditions. Results of the brazing experiments indicated that pure silver worked very well for brazing under both conventional and high heating rate scenarios. Similarly, pure silver brazed well for both the PVD layers and the braze alloy shims. The gold and gold-containing brazes had problems, mainly due to the high diffusivity of gold in copper. These problems led to the necessity of overdriving the temperature to ensure melting, the presence of porosity in the joint, and very wide braze joints. Based on the overall findings of this study, a two

  9. The method for production of high purity carrier free ortophosphoric acid labeled with isotopes Phosphorus-32 and Phosphorus-33

    International Nuclear Information System (INIS)

    Abdukayumov, M.N.; Abdusalyamov, A.N.; Chistyakov, P.G.; Yuldashev, B.S.

    2001-01-01

    Extensive application for various radioactive isotopes was found in an extremity of the 20-Th century in a science and production. Labeled compounds are used with growing effectiveness in a molecular biology, gene engineering, medicine and other areas. Phosphorus-32 and Phosphorus-33 isotopes as a different labeled compounds that are used mainly in molecular biology are produced at the Radiopreparat enterprise of the Institute of Nuclear Physics of Academy of Sciences of Uzbekistan Republic. The quality of labeled preparations is very high. The specifications for above mentioned preparations corresponds to demands most of customers in different countries. P-32 or P-33 labeled orthophosphoric acid has high radiochemical purity (more than 99 %) and specific radioactivity close to theoretical. Orthophosphoric acid prepared by the described above method has radiochemical purity about 95 % and output of the target product 99%

  10. Nonlinear dynamic behaviors and control based on simulation of high-purity heat integrated air separation column.

    Science.gov (United States)

    Fu, Yao; Liu, Xinggao

    2015-03-01

    In this paper, the dynamic behaviors on the basis of simulation for high-purity heat integrated air separation column (HIASC) are studied. A nonlinear generic model control (GMC) scheme is proposed based on the nonlinear behavior analyses of a HIASC process, and an adaptive generic model control (AGMC) scheme is further presented to correct the model parameters online. Related internal model control (IMC) scheme and multi-loop PID (M-PID) scheme are also developed as the comparative base. The comparative researches are carried out among these linear and nonlinear control schemes in detail. The simulation research results show that the proposed AGMC schemes present advantages in both servo control and regulatory control for the high-purity HIASC. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  11. Potential utility of eGFP-expressing NOG mice (NOG-EGFP as a high purity cancer sampling system

    Directory of Open Access Journals (Sweden)

    Shima Kentaro

    2012-06-01

    Full Text Available Abstract Purpose It is still technically difficult to collect high purity cancer cells from tumor tissues, which contain noncancerous cells. We hypothesized that xenograft models of NOG mice expressing enhanced green fluorescent protein (eGFP, referred to as NOG-EGFP mice, may be useful for obtaining such high purity cancer cells for detailed molecular and cellular analyses. Methods Pancreato-biliary cancer cell lines were implanted subcutaneously to compare the tumorigenicity between NOG-EGFP mice and nonobese diabetic/severe combined immunodeficiency (NOD/SCID mice. To obtain high purity cancer cells, the subcutaneous tumors were harvested from the mice and enzymatically dissociated into single-cell suspensions. Then, the cells were sorted by fluorescence-activated cell sorting (FACS for separation of the host cells and the cancer cells. Thereafter, the contamination rate of host cells in collected cancer cells was quantified by using FACS analysis. The viability of cancer cells after FACS sorting was evaluated by cell culture and subsequent subcutaneous reimplantation in NOG-EGFP mice. Results The tumorigenicity of NOG-EGFP mice was significantly better than that of NOD/SCID mice in all of the analyzed cell lines (p  Conclusions This method provides a novel cancer sampling system for molecular and cellular analysis with high accuracy and should contribute to the development of personalized medicine.

  12. Uranium recovery from phosphate fertilizer in the form of a high purity compound

    International Nuclear Information System (INIS)

    Bunus, F.; Coroianu, T.; Filip, G.; Filip, D.

    2001-01-01

    Uranium recovery from phosphate fertilizer industry is based on a one cycle extraction-stripping process. The process was experimented on both sulfuric and nitric acid attack of phosphate rock when uranium is dissolved in phosphoric acid (WPA) or phosphonitric (PN) solution respectively. The WPA and PN solution must be clarified. In the first alternative by ageing and settling and in the second by settling in the presence of flocculant. The organic components must be removed on active carbon for WPA only since in the case of nitric attack calcined phosphates are used. In both alternatives uranium is extracted from aqueous acidic solutions in the same time with the rare earths (REE), by di(2-ethylhexyl) phosphate (DEPA) as basic extractants, eventually in the presence of octylphosphine oxide (TOPO) as synergic agent. The stripping process is carried out in two stages: in the first stage REE are stripped and precipitated by HF or NH 4 F + H 2 S0 4 and in the second stage uranium as U(VI) is stripped by the same reagents but in the presence of Fe(II) as reductant for U(VI) to U(IV) inextractible species. Tetravalent uranium is also precipitated as green cake either UF 4 xH 2 0 or (NH 4 ) 7 U 6 F 31 as dependent on reagents HF or NH 4 F + H 2 S0 4 . Uranium stripping is possible for PN solution only if HNO 3 partially extracted is previously washed out by a urea solution. The green cake washed and filtered is dissolved in nitric acid in presence of Al(OH)3 as complexant for F. The filtered nitric solution is adjusted to 3-5 mol/L HNO 3 and extracted by 20% TBP when uranium is transferred to the organic phase which after scrubbing is stripped in the classic way with acidulated (HN0 3 ) demineralized water. Uranium is precipitated as diuranate of high purity. Rare earths left in the aqueous raffinate are extracted by pure TBP from 8-10 mol/L HNO 3 medium. The stripping process takes place with acidulated water. Rare earths are precipitated as hydroxides. (author)

  13. Methods to improve and understand the sensitivity of high purity germanium detectors for searches of rare events

    Energy Technology Data Exchange (ETDEWEB)

    Volynets, Oleksandr

    2012-07-27

    Observation of neutrinoless double beta-decay could answer fundamental questions on the nature of neutrinos. High purity germanium detectors are well suited to search for this rare process in germanium. Successful operation of such experiments requires a good understanding of the detectors and the sources of background. Possible background sources not considered before in the presently running GERDA high purity germanium detector experiment were studied. Pulse shape analysis using artificial neural networks was used to distinguish between signal-like and background-like events. Pulse shape simulation was used to investigate systematic effects influencing the efficiency of the method. Possibilities to localize the origin of unwanted radiation using Compton back-tracking in a granular detector system were examined. Systematic effects in high purity germanium detectors influencing their performance have been further investigated using segmented detectors. The behavior of the detector response at different operational temperatures was studied. The anisotropy effects due to the crystallographic structure of germanium were facilitated in a novel way to determine the orientation of the crystallographic axes.

  14. Isolation of High-Purity Extracellular Vesicles by Extracting Proteins Using Aqueous Two-Phase System.

    Directory of Open Access Journals (Sweden)

    Jongmin Kim

    Full Text Available We present a simple and rapid method to isolate extracellular vesicles (EVs by using a polyethylene glycol/dextran aqueous two-phase system (ATPS. This system isolated more than ~75% of melanoma-derived EVs from a mixture of EVs and serum proteins. To increase the purity of EVs, a batch procedure was combined as additional steps to remove protein contaminants, and removed more than ~95% of the protein contaminants. We also performed RT-PCR and western blotting to verify the diagnostic applicability of the isolated EVs, and detected mRNA derived from melanoma cells and CD81 in isolated EVs.

  15. Near-field beam focusing by a single bare subwavelength metal slit with the high-index transmission space.

    Science.gov (United States)

    Guo, Yan; Zhao, Bo; Yang, Jianjun

    2013-06-17

    We theoretically demonstrate that a single bare subwavelength metal slit without any surrounding corrugations can have a capability to steer the incident light into focusing patterns by introducing a high index in the transmission half-space. The focusing properties are identified to depend on both the slit width and the output permittivity. The underlying physics lies in the interference of quasi-cylindrical waves scattered from the slit, and our proposed model agrees well with the simulation results. This finding is believed to inspire some novel ideas for the nano-optics design.

  16. High Purity Hydrogen Production with In-Situ Carbon Dioxide and Sulfur Capture in a Single Stage Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Nihar Phalak; Shwetha Ramkumar; Daniel Connell; Zhenchao Sun; Fu-Chen Yu; Niranjani Deshpande; Robert Statnick; Liang-Shih Fan

    2011-07-31

    Enhancement in the production of high purity hydrogen (H{sub 2}) from fuel gas, obtained from coal gasification, is limited by thermodynamics of the water gas shift (WGS) reaction. However, this constraint can be overcome by conducting the WGS in the presence of a CO{sub 2}-acceptor. The continuous removal of CO{sub 2} from the reaction mixture helps to drive the equilibrium-limited WGS reaction forward. Since calcium oxide (CaO) exhibits high CO{sub 2} capture capacity as compared to other sorbents, it is an ideal candidate for such a technique. The Calcium Looping Process (CLP) developed at The Ohio State University (OSU) utilizes the above concept to enable high purity H{sub 2} production from synthesis gas (syngas) derived from coal gasification. The CLP integrates the WGS reaction with insitu CO{sub 2}, sulfur and halide removal at high temperatures while eliminating the need for a WGS catalyst, thus reducing the overall footprint of the hydrogen production process. The CLP comprises three reactors - the carbonator, where the thermodynamic constraint of the WGS reaction is overcome by the constant removal of CO{sub 2} product and high purity H{sub 2} is produced with contaminant removal; the calciner, where the calcium sorbent is regenerated and a sequestration-ready CO{sub 2} stream is produced; and the hydrator, where the calcined sorbent is reactivated to improve its recyclability. As a part of this project, the CLP was extensively investigated by performing experiments at lab-, bench- and subpilot-scale setups. A comprehensive techno-economic analysis was also conducted to determine the feasibility of the CLP at commercial scale. This report provides a detailed account of all the results obtained during the project period.

  17. Mechanical energy losses in plastically deformed and electron plus neutron irradiated high purity single crystalline molybdenum at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Zelada, Griselda I. [Laboratorio de Materiales, Escuela de Ingenieria Electrica, Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Avda. Pellegrini 250, 2000 Rosario (Argentina); Lambri, Osvaldo Agustin [Laboratorio de Materiales, Escuela de Ingenieria Electrica, Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Avda. Pellegrini 250, 2000 Rosario (Argentina); Instituto de Fisica Rosario - CONICET, Member of the CONICET& #x27; s Research Staff, Avda. Pellegrini 250, 2000 Rosario (Argentina); Bozzano, Patricia B. [Laboratorio de Microscopia Electronica, Unidad de Actividad Materiales, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Avda. Gral. Paz 1499, 1650 San Martin (Argentina); Garcia, Jose Angel [Departamento de Fisica Aplicada II, Facultad de Ciencias y Tecnologia, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao, Pais Vasco (Spain)

    2012-10-15

    Mechanical spectroscopy (MS) and transmission electron microscopy (TEM) studies have been performed in plastically deformed and electron plus neutron irradiated high purity single crystalline molybdenum, oriented for single slip, in order to study the dislocation dynamics in the temperature range within one third of the melting temperature. A damping peak related to the interaction of dislocation lines with both prismatic loops and tangles of dislocations was found. The peak temperature ranges between 900 and 1050 K, for an oscillating frequency of about 1 Hz. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Preparation of uniform nanoparticles of ultra-high purity metal oxides, mixed metal oxides, metals, and metal alloys

    Science.gov (United States)

    Woodfield, Brian F.; Liu, Shengfeng; Boerio-Goates, Juliana; Liu, Qingyuan; Smith, Stacey Janel

    2012-07-03

    In preferred embodiments, metal nanoparticles, mixed-metal (alloy) nanoparticles, metal oxide nanoparticles and mixed-metal oxide nanoparticles are provided. According to embodiments, the nanoparticles may possess narrow size distributions and high purities. In certain preferred embodiments, methods of preparing metal nanoparticles, mixed-metal nanoparticles, metal oxide nanoparticles and mixed-metal nanoparticles are provided. These methods may provide tight control of particle size, size distribution, and oxidation state. Other preferred embodiments relate to a precursor material that may be used to form nanoparticles. In addition, products prepared from such nanoparticles are disclosed.

  19. Preparation of High-purity Lactulose through Efficient Recycle of Catalyst Sodium Aluminate and Nanofiltration: A Pilot-scale Purification.

    Science.gov (United States)

    Wang, Mingming; Tessema, Habtamu Admassu; Gasmalla, Mohammed A A; Hua, Xiao; Yang, Ruijin

    2018-04-16

    Lactulose, a valuable lactose-originated "bifidus factor" product, is exclusively produced by chemical-based isomerization commercially. Complexing agent of sodium aluminate exhibited high conversion efficiency and strong recyclable stability is more practical for industrial applications. In this study, efficient purification of high-purity lactulose through recycling of sodium aluminate and further desalination by nanofiltration (NF) was implemented in a pilot scale. Over 99.5% of catalyst was prior recycled in the form of Al(OH) 3 precipitate by pH-induced precipitation and centrifugation, residual aluminum was further absorbed by ion exchange resin to an acceptable level (≤10 mg Kg -1 ). Subsequently, impurities (monosaccharides and NaCl) were ideally separated from lactulose syrup by NF process based on their significant retention differences (lactulose: 94.8-97.2%> lactose: 86.2-93.5%> monosaccharides: 36.3-48.7%> NaCl: 9.5-31.1%). High-purity (>95 %) lactulose was obtained with yield >90% in both constant and variable volume diafiltration modes (CVD/VVD) when volume dilution ratio (V c /V f ) was 4.0 and 2.5, respectively. Both experimental and predicted results showed that VVD mode was more water-saving in practical. This is the first trial purification of lactulose syrup from chemical isomerization of lactose catalyzed by sodium aluminate, and the applied methodology is a promising industrial scale purification strategy. This article is protected by copyright. All rights reserved.

  20. Stress relaxation in 'aged high-purity aluminium at room temperature

    International Nuclear Information System (INIS)

    Butt, M.Z.; Haq, I.U.

    1993-01-01

    Stress relaxation in 99.996% Al polycrystals of average grain diameter 0.30, 0.42 and 0.51 mm, annealed at 500 deg. C and 'aged' for six months at room temperature, have been studied as a function of initial stress level from which relaxation at constant strain was allowed to start. The results obtained were compared with those for 'un-aged' Al specimens of the same purity and grain size. The intrinsic height of the thermally activable energy barrier (1.6 eV) evaluated for 'aged' Al is comparable with that (1.9 eV) for 'un-aged' Al, and is of the order of magnitude for recovery processes. In 'aged' specimens, the relaxation rate at a given stress level is larger and associated activation volume is smaller than that in 'un-aged' specimens. This is probably due to the diffusion of vacancies and/or residual impurity atoms to the cores to edge dislocations in 'aged' specimens; the length of dislocation segment involved in unit activation process therefore gets shortened compared with that in 'un-aged' specimens. (author)

  1. High-Purity Composite Briquette for Direct UMG-Si Production in Arc Furnaces

    Science.gov (United States)

    Perruchoud, Raymond; Fischer, Jean-Claude

    2013-12-01

    In metallurgical grade Si (MG-Si), the coal (B) and charcoal (P) contents are on average above 30 ppm as the carbon reduction materials used in the arc furnace are either rich in B or in P. A decrease of both impurities by a factor of 3 using purer raw materials would allow for the direct production of the upgraded metallurgical grade (UMG).This would significantly improve the efficiency of the resulting photovoltaic (PV) cells made with the refined solar grade silicon (SoG-Si) or massively decrease the costs of Si purification by shortening the number of steps needed for reaching B and P contents below 1 ppm requested for the SoG-Si used for the PV cells. A composite C/SiO2 briquette fulfilling the purity targets for the direct production of UMG-Si in the arc furnace was developed. The composite contains several carbon materials with different levels of reactivities and quartz sand. The raw materials aspects, the paste and briquette preparation, as well as the final carbonization step are discussed. The finished briquettes are free of volatiles and are mechanically and thermally very stable, thus, ensuring stable arc furnace charges with minimum losses of dust and SiO gas. Semi-industrial trials including the downstream purification steps for the production of SoG-Si by a metallurgical low-cost route are contemplated.

  2. Structural and mechanical behaviour of severe plastically deformed high purity aluminium sheets processed by constrained groove pressing technique

    International Nuclear Information System (INIS)

    Satheesh Kumar, S.S.; Raghu, T.

    2014-01-01

    Highlights: • High purity aluminium sheets constrained groove pressed up to plastic strain of 5.8. • Microstructural evolution studied by TEM and X-ray diffraction profile analysis. • Ultrafine grained structure with grain size ∼900 nm achieved in sheets. • Yield strength increased by 5.3 times and tensile strength doubled after first pass. • Enhanced deformation homogeneity seen with increased accumulated plastic strain. - Abstract: High purity aluminium sheets (∼99.9%) are subjected to intense plastic straining by constrained groove pressing method successfully up to 5 passes thereby imparting an effective plastic strain of 5.8. Transmission electron microscopy studies of constrained groove pressed sheets divulged significant grain refinement and the average grain sizes obtained after five pass is estimated to be ∼0.9 μm. In addition to that, microstructural evolution of constrained groove pressed sheets is characterized by X-ray diffraction peak profile analysis employing Williamson–Hall method and the results obtained fairly concur with electron microscopy findings. The tensile behaviour evolution with increased straining indicates substantial improvement of yield strength by ∼5.3 times from 17 MPa to 90 MPa during first pass corroborated to grain refinement observed. Marginal increase in strengths is noticed during second pass followed by minor drop in strengths attributed to predominance of dislocation recovery is noticed in subsequent passes. Quantitative assessment of degree of deformation homogeneity using microhardness profiles reveal relatively better strain homogeneity at higher number of passes

  3. Synthesis of high purity tungsten nanoparticles from tungsten heavy alloy scrap by selective precipitation and reduction route

    Energy Technology Data Exchange (ETDEWEB)

    Kamal, S.S. Kalyan, E-mail: kalyanchem03@rediffmail.com; Sahoo, P.K.; Vimala, J.; Shanker, B.; Ghosal, P.; Durai, L.

    2016-09-05

    In this paper we report synthesis of tungsten nanoparticles of high purity >99.7 wt% from heavy alloy scrap using a novel chemical route of selective precipitation and reduction. The effect of Poly(vinylpyrrolidone) polymer on controlling the particle size is established through FTIR spectra and corroborated with TEM images, wherein the average size decreased form 210 to 45 nm with increasing PVP content from zero to 2 g under different experimental conditions. This process is economical as raw material is a scrap and the efficiency of the reaction is >95%. - Highlights: • Tungsten nanoparticles were synthesized from tungsten heavy alloy scrap. • A novel chemical route of precipitation and reduction with Poly(vinylpyrrolidone) polymer as stabilizer is reported. • The average size decreased form 210 to 45 nm with increasing PVP content from zero to 2 g. • High pure tungsten nanoparticles of >99.7% purity could be synthesized using this route. • Efficiency of the reaction is >95%.

  4. Thermal behavior of Ni (99.967% and 99.5% purity) deformed to an ultra-high strain by high pressure torsion

    DEFF Research Database (Denmark)

    Zhang, H.W.; Huang, Xiaoxu; Pippan, R.

    2010-01-01

    Polycrystalline Ni of two purities (99.967% (4N) and 99.5% (2N)) was deformed to an ultra-high strain of εvM = 100 (εvM, von Mises strain) by high pressure torsion at room temperature. The 4N and 2N samples at this strain are nanostructured with an average boundary spacing of 100 nm, a high density...

  5. Industrial-scale separation of high-purity single-chirality single-wall carbon nanotubes for biological imaging

    Science.gov (United States)

    Yomogida, Yohei; Tanaka, Takeshi; Zhang, Minfang; Yudasaka, Masako; Wei, Xiaojun; Kataura, Hiromichi

    2016-06-01

    Single-chirality, single-wall carbon nanotubes are desired due to their inherent physical properties and performance characteristics. Here, we demonstrate a chromatographic separation method based on a newly discovered chirality-selective affinity between carbon nanotubes and a gel containing a mixture of the surfactants. In this system, two different selectivities are found: chiral-angle selectivity and diameter selectivity. Since the chirality of nanotubes is determined by the chiral angle and diameter, combining these independent selectivities leads to high-resolution single-chirality separation with milligram-scale throughput and high purity. Furthermore, we present efficient vascular imaging of mice using separated single-chirality (9,4) nanotubes. Due to efficient absorption and emission, blood vessels can be recognized even with the use of ~100-fold lower injected dose than the reported value for pristine nanotubes. Thus, 1 day of separation provides material for up to 15,000 imaging experiments, which is acceptable for industrial use.

  6. Trace analysis measurements in high-purity aluminium by means of radiochemical neutron and proton activation analysis

    International Nuclear Information System (INIS)

    Egger, K.P.

    1987-01-01

    The aim of the study consisted in the development of efficient radiochemical composite processes and activation methods for the multi-element determination of traces within the lower ng range in high-purity aluminium. More than 50 elements were determined with the help of activation with reactor neutrons; the selective separation of matrix activity (adsorption with hydrated antimony pentoxide) led to a noticeable improvement of detectability, as compared with instrumental neutron activation analysis. Further improvements were achieved with the help of radiochemical group separations in ion exchangers or with the help of the selective separation of the pure beta-emitting elements. Over 20 elements up to high atomic numbers were determined by means of activating 13 MeV protons and 23 Me protons. In this connection, improvements of the detection limit by as a factor of 10 were achieved with radiochemical separation techniques, as compared with pure instrumental proton activation analysis. (RB) [de

  7. Application of a Barrier Filter at a High Purity Synthetic Graphite Plant, CRADA 99-F035, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    National Energy Technology Laboratory

    2000-08-31

    Superior Graphite Company and the US Department of Energy have entered into a Cooperative Research and Development Agreement (CRADA) to study the application of ceramic barrier filters at its Hopkinsville, Kentucky graphite plant. Superior Graphite Company is a worldwide leader in the application of advanced thermal processing technology to produce high purity graphite and carbons. The objective of the CRADA is to determine the technical and economic feasibility of incorporating the use of high-temperature filters to improve the performance of the offgas treatment system. A conceptual design was developed incorporating the ceramic filters into the offgas treatment system to be used for the development of a capital cost estimate and economic feasibility assessment of this technology for improving particulate removal. This CRADA is a joint effort of Superior Graphite Company, Parsons Infrastructure and Technology Group, and the National Energy Technology Laboratory (NETL) of the US Department of Energy (DOE).

  8. Procoagulant properties of bare and highly PEGylated vinyl-modified silica nanoparticles.

    Science.gov (United States)

    Tavano, Regina; Segat, Daniela; Reddi, Elena; Kos, Janko; Rojnik, Matija; Kocbek, Petra; Iratni, Selma; Scheglmann, Dietrich; Colucci, Mario; Echevarria, Iria Maria Rio; Selvestrel, Francesco; Mancin, Fabrizio; Papini, Emanuele

    2010-08-01

    Undesired alterations of the blood clotting balance may follow the intravascular injection of nanotherapeutics/diagnostics. Here, we tested the procoagulant activity of synthetic amorphous silica (SAS) and organically modified silica (ORMOSIL) nanoparticles (NPs) and whether a high-density polyethylene glycol coating minimizes these effects. Hageman factor- and tissue factor-dependent activation of human blood/plasma coagulation, and binding to human monocytes, endothelial cells and platelets were quantified in vitro using naked and PEGylated ORMOSIL-NPs. Their effects were compared with those of SAS-NPs, present in many industrial products, and of poly(lactic-co-glycolic acid)- and small unilamellar vesicles-NPs, already approved for use in humans. Both SAS-NPs and ORMOSIL-NPS presented a significant procoagulant activity. However, highly PEGylated ORMOSIL-NPs were particularly averse to the interaction with the soluble factors and cellular elements that may lead to intravascular blood coagulation. Stealth, highly PEGylated ORMOSIL-NPs with a poor procoagulant activity can be used as starting blocks to design hemocompatible nanomedical-devices.

  9. Recycling enhancement with n-bare and qeff in high density discharges on JT-60U

    International Nuclear Information System (INIS)

    Asakura, N.; Shimizu, K.; Hosogane, N.; Itami, K.; Tsuji, S.; Shimada, M.

    1995-01-01

    Quantitative studies of recycling, particle flux and divertor plasma parameters have been made in high density L mode discharges on the JT-60U tokamak, with the ion ∇B drift towards the divertor. The diagnostics used were H α /D α photon emission detectors and a Langmuir probe array. Deuterium particle influx Φ Dα and particle outflux Φ probe measurements were in fairly good agreement in both the inboard and the outboard divertors. The relationship between the particle recycling and the divertor plasma parameters was investigated to clarify the conditions under which a cold and dense divertor plasma was formed. Φ Dα was raised from 10 22 to 10 23 s -1 with increasing n-bar e and q eff . Recycling in the inboard divertor was amplified substantially owing to the appearance of a third peak in the local recycling profile, displace from the separatrix. Numerical results from an interpretative divertor code showed that the particle amplification factor G div in the inboard divertor was larger than that in the outboard divertor, and that both increased with increasing q eff and n-bar e . These results explain the observed dependence of the recycling on the parameters n-bar e and q eff discharges. The maximum electron density n e,div in the outboard divertor was (4-7) x 10 19 m -3 , exceeding n-bar e for high q eff discharges. In the same discharges, the divertor electron temperature T e,div was reduced to about 20 eV before MARFEs were observed. High n-bar e and q eff operation was favourable for obtaining a cold and dense divertor plasma. (author). 39 refs, 21 figs

  10. Converting biomass waste into microporous carbon with simultaneously high surface area and carbon purity as advanced electrochemical energy storage materials

    Science.gov (United States)

    Sun, Fei; Wang, Lijie; Peng, Yiting; Gao, Jihui; Pi, Xinxin; Qu, Zhibin; Zhao, Guangbo; Qin, Yukun

    2018-04-01

    Developing carbon materials featuring both high accessible surface area and high structure stability are desirable to boost the performance of constructed electrochemical electrodes and devices. Herein, we report a new type of microporous carbon (MPC) derived from biomass waste based on a simple high-temperature chemical activation procedure. The optimized MPC-900 possesses microporous structure, high surface area, partially graphitic structure, and particularly low impurity content, which are critical features for enhancing carbon-based electrochemical process. The constructed MPC-900 symmetric supercapacitor exhibits high performances in commercial organic electrolyte such as widened voltage window up to 3 V and thereby high energy/power densities (50.95 Wh kg-1 at 0.44 kW kg-1; 25.3 Wh kg-1 at 21.5 kW kg-1). Furthermore, a simple melt infiltration method has been employed to enclose SnO2 nanocrystals onto the carbon matrix of MPC-900 as a high-performance lithium storage material. The obtained SnO2-MPC composite with ultrafine SnO2 nanocrystals delivers high capacities (1115 mAh g-1 at 0.2 A g-1; 402 mAh g-1 at 10 A g-1) and high-rate cycling lifespan of over 2000 cycles. This work not only develops a microporous carbon with high carbon purity and high surface area, but also provides a general platform for combining electrochemically active materials.

  11. Influence of sulphur and phosphorus on the hot deformation of Fe-Cr 13% high purity steel

    International Nuclear Information System (INIS)

    Lahreche, M.; Bouzabata, B.; Kobylanski, A.

    1995-01-01

    A series of Fe-Cr13%-C high purity steels containing increasing volume fractions of Sulphur (30, 60 and 100ppm) and Phosphorus (30, 60 and 100ppm) were prepared in order to study their hot deformation properties by tensile tests at various strain rates (10 -1 s -1 to 10 -4 s -1 ) and at temperatures from 700 C to 1100 C. It is observed that the hot ductility is lowered at 1000 C with the addition of sulphur. However, this decrease is relatively small (about 30% for 100ppm of sulphur) and quite similar for all additions of sulphur. When phosphorus is added, the embrittlement is along the whole deformed specimen. The usual criteria of ductility by parameter Z do not seem to be sufficient to describe this embrittlement. (orig.)

  12. Experimental and finite-element analysis of the anisotropic response of high-purity α-titanium in bending

    International Nuclear Information System (INIS)

    Nixon, Michael E.; Lebensohn, Ricardo A.; Cazacu, Oana; Liu Cheng

    2010-01-01

    In this paper, we present results of four-point bending tests performed on beams of high-purity α-titanium material. These tests have been performed at room temperature for different beam configurations and loading orientations with respect to the orthotropy axes of the material. Digital image correlation was used to determine local strains in the deformed beams. Experimental results compare very well with the predictions of finite-element simulations obtained using the elastic/plastic model developed by Nixon et al. (2010) . Specifically, we compare local deformations and the cross-sections of each beam for all loading configurations. We show that the model predicts with great accuracy the tension-compression asymmetry and the evolving anisotropy of the material. The experimentally observed upward shift of the neutral axis, as well as the rigidity of the response along the hard to deform c-axes are very well described by the proposed model.

  13. Phase transformations of high-purity PbI{sub 2} nanoparticles synthesized from lead-acid accumulator anodes

    Energy Technology Data Exchange (ETDEWEB)

    Malevu, T.D., E-mail: malevutd@ufs.ac.za; Ocaya, R.O.; Tshabalala, K.G.

    2016-09-01

    High-purity hexagonal lead iodide nanoparticles have been synthesized from a depleted sealed lead acid battery anode. The synthesized product was found to consist of the rare 6R polytype form of PbI{sub 2} that is thought to have good potential in photovoltaic applications. We investigate the effects of annealing time and post-melting temperature on the structure and optical properties using 1.5418 Å CuKα radiation. Photoluminescence measurements were done under 150 W/221 nm wavelength xenon excitation. Phase transformation was observed through XRD peaks when annealing time increased from 0.5–5 h. The nanoparticle grain size and inter-planar distance appeared to be independent of annealing time. PL measurements show three broad peaks in a range of 400 nm to 700 nm that are attributed to excitonic, donor–acceptor pair and luminescence bands from the deep levels.

  14. Preparation and photoluminescence characterization of high-purity CdTe single crystals: purification effect of normal freezing on tellurium and cadmium telluride

    Science.gov (United States)

    Song, S. H.; Wang, J.; Isshiki, M.

    2002-03-01

    Extremely high-purity CdTe single crystals have been obtained by the traditional vertical Bridgman technique, beginning with the refining of tellurium material by the normal freezing method. The purification effect of normal freezing on tellurium has been confirmed to be very effective. This effect was also used to prepare extremely high-purity CdTe single crystals. The crystals were characterized by low temperature high-resolution photoluminescence (PL) spectroscopy. Only a sharp peak at 1.5896 eV was detected in the PL spectrum. The full-width at half-maximum is prepared by the Bridgman method.

  15. Z, velocity, and charge dependence of zero-degree electron ''cusps'' from charge transfer to continuum states of bare and highly ionized projectiles

    International Nuclear Information System (INIS)

    Vane, C.R.; Sellin, I.A.; Suter, M.; Alton, G.D.; Elston, S.B.; Griffin, P.M.; Thoe, R.S.

    1978-01-01

    Data on continuum electron capture and loss for bare and highly ionizated C/sup q/+, O/sup q/+ ions traversing Ar at energies 1.6--2.8 MeV/A reveal striking disagreements with corresponding theories. We demonstrate a velocity-independent (approx. Z/sup 2.2tsplus-or-minusts0.2/) scaling for continuum capture by bare ions, a Z-independent velocity scaling, and an approximately q-independent (q = 6,7,8) equality of continuum electron-capture and -loss cross sections at velocities corresponding to approx. 2 MeV/A

  16. Acetic acid and pepsin result in high yield, high purity and low macrophage response collagen for biomedical applications.

    Science.gov (United States)

    Delgado, Luis M; Shologu, Naledi; Fuller, Kieran; Zeugolis, Dimitrios I

    2017-10-25

    Collagen based devices are frequently associated with foreign body response. Although several pre- (e.g. species, state of animal, tissue) and post- (e.g. cross-linking, scaffold architecture) extraction method factors have a profound effect on foreign body response, little is known about which and how during the extraction process factors mediate foreign body response. In this study, we assessed the influence of acetic acid and hydrochloric acid and the utilisation or not of pepsin or salt precipitation during collagen extraction on the yield, purity, free amines, denaturation temperature, resistance to collagenase degradation and macrophage response. Acetic acid/pepsin extracted collagen exhibited the highest yield, purity and free amine content and the lowest denaturation temperature. No differences in resistance to collagenase digestion were detected between the groups. Although all treatments exhibited similar macrophage morphology comprised of round cells (M1 phenotype), elongated cells (M2 phenotype) and cell aggregates (foreign body response), significantly more elongated cells were observed on HC films. Although no differences in metabolic activity were observed between the groups, the DNA concentration was significantly lower for the hydrochloric acid treatments. Further, cytokine analysis revealed that hydrochloric acid treatments induced significantly higher IL-1β and TNF-α release with respect to acetic acid treatments. Salt precipitation did not influence the parameters assessed. Collectively, these data suggest that during the collagen extraction process variables should also be monitored as, evidently, they affect the physicochemical and biological properties of collagen preparations.

  17. Synthesis and characterization of high-purity gold nanoparticles by laser ablation method using low-energy Nd:YAG laser 1064 nm

    Science.gov (United States)

    Khumaeni, Ali; Setia Budi, Wahyu; Sutanto, Heri

    2017-11-01

    High-purity gold nanoparticles (GNPs) has been successfully synthesized by using laser ablation method utilizing low-power neodymium yttrium aluminum garnet (Nd:YAG) laser at the fundamental wavelength. Experimentally, pulse laser beam (Nd:YAG laser, 1064 nm, 7 ns, 30 mJ) was directed and focused onto a high-purity gold sheet (99.95%), which was placed into a pure liquid of deionized water, to produce GNPs colloid. Dark-red color colloid of high-purity GNPs was successfully synthesized. The GNPs had a spherical shape with an average diameter of 23.5 nm and standard deviation of 6.4 nm. The surface plasma resonance was centered at wavelength maximum at 520 nm.

  18. Influence of dissolved oxygen, dissolved hydrogen and surface film on the corrosion products release from stainless steel in high purity water at room temperature

    International Nuclear Information System (INIS)

    Iwahori, Toru; Kato, Shunji; Wada, Kunihisa; Kanbe, Hiromi; Mizuno, Takayuki

    1983-01-01

    The influence of dissolved oxygen, dissolved hydrogen and surface film on corrosion products release from SUS 304 stainless steel was studied in high purity water at room temperature. The determination of corrosion products released was performed by using millipore filter (0.45μm), cation-exchange resins and anion-exchange resins. The selective release of Fe component from stainless steel occurred in deoxygenated water containing saturated hydrogen or below 120 ppb oxygen, while the selective release of Co and Ni occurred in oxygenated water containing above 8 ppm oxygen. In the case of preautoclaved stainless steel coated with R 3 O 4 (spinel type oxides) film, the selective release of Co and Ni occurred in any high purity water, regardless of dissolved oxygen or dissolved hydrogen. Similar selective dissolution of Co from cobalt ferrite occurred in any high purity water, regardless of dissolved oxygen or dissolved hydrogen. Relation between corrosion potential and release was discussed. (author)

  19. Highly purified water production technology. The influence of water purity on steam quality

    International Nuclear Information System (INIS)

    Ganter, J.

    1975-01-01

    The fundamental question related to high-pressure steam generation, intended for powering steam turbines, concerns steam production conditions based on constant quality standards. The characteristics of water (salinity, silica concentration) are indicated for a given steam quality as a function of the pressure. Two processes for the purification of feedwater for high pressure boilers are described: a treatment using precoated cellulose or resin filters and a treatment using mixed-bed ion exchangers. When ultrapure water is required, the demineralized water is filtred using microfiltration and ultrafiltration processes [fr

  20. High purity of human oligodendrocyte progenitor cells obtained from neural stem cells: suitable for clinical application.

    Science.gov (United States)

    Wang, Caiying; Luan, Zuo; Yang, Yinxiang; Wang, Zhaoyan; Wang, Qian; Lu, Yabin; Du, Qingan

    2015-01-30

    Recent studies have suggested that the transplantation of oligodendrocyte progenitor cells (OPCs) may be a promising potential therapeutic strategy for a broad range of diseases affecting myelin, such as multiple sclerosis, periventricular leukomalacia, and spinal cord injury. Clinical interest arose from the potential of human stem cells to be directed to OPCs for the clinical application of treating these diseases since large quantities of high quality OPCs are needed. However, to date, there have been precious few studies about OPC induction from human neural stem cells (NSCs). Here we successfully directed human fetal NSCs into highly pure OPCs using a cocktail of basic fibroblast growth factor, platelet-derived growth factor, and neurotrophic factor-3. These cells had typical morphology of OPCs, and 80-90% of them expressed specific OPC markers such as A2B5, O4, Sox10 and PDGF-αR. When exposed to differentiation medium, 90% of the cells differentiated into oligodendrocytes. The OPCs could be amplified in our culture medium and passaged at least 10 times. Compared to a recent published method, this protocol had much higher stability and repeatability, and OPCs could be obtained from NSCs from passage 5 to 38. It also obtained more highly pure OPCs (80-90%) via simpler and more convenient manipulation. This study provided an easy and efficient method to obtain large quantities of high-quality human OPCs to meet clinical demand. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. On the radiochemical purity of elementary 35S with high specific activity

    International Nuclear Information System (INIS)

    Todorovsky, D.S.; Kostadinov, K.N.; Efremova, Yu.N.

    1979-01-01

    Radiochemical composition and chemical changes with increasing storage time of benzene solutions and of solid species of elementary 35 S with high specific activity are studied. The dependence of the stability on the specific activity and the radioactive concentration is shown and some tentative limits are given for permissible storage periods. (author)

  2. The flow stress of high-purity refractory body-centred cubic metals and its modification by atomic defects

    International Nuclear Information System (INIS)

    Seeger, A.

    1995-01-01

    The strong temperature and strain-rate dependence of the flow stress of high-purity refractory body-centred cubic metals has been shown to be an intrinsic property and is usually ascribed to a high Peierls barrier of a o left angle 111 right angle /2 screw dislocations. These barriers are overcome by the formation of kink pairs on the screw dislocations. The paper reports on recent, very complete flow-stress data on ultra-high purity Mo crystals obtained by two different experimental techniques and covering the temperature range 4 K to 460 K. The results are in accord with earlier work of Brunner and Diehl on α-Fe, who showed that below the so-called knee temperature, T K , three regimes in the temperature variation of the flow-stress should be distinguished. Two of them are fully accounted for by the same glide mechanism, namely elementary glide steps on {211} planes. The so-called upper bend separating these two regimes in an inherent feature of the theory of kink-pair formation and does not indicate a change in the glide mechanism. There is, however, strong evidence that the so-called lower bend, separating the range of {211} elementary glide steps from the low-temperature flow-stress regime, is due to a change in the glide mechanism. It is argued that at the lower bend the screw-dislocation cores undergo a ''first-order phase transition'' from a low-temperature configuration that allows glide of a given screw dislocation on any of its three {110} glide planes to a high-temperature configuration that can glide only on one definite {211} plane. Between T K and the lower-bend temperature, T, bcc metals may show the unique phenomena of alloy and irradiation softening. With regard to the latter phenomenon, Brunner and Diehl distinguish between ''primary'' and ''secondary'' softening. It is shown that alloy softening and the ''secondary irradiation softening'' of bcc metals may be explained by an ''overheating'' of the phase transition in the dislocation core. (orig./WL)

  3. High-Purity Hybrid Organolead Halide Perovskite Nanoparticles Obtained by Pulsed-Laser Irradiation in Liquid

    KAUST Repository

    Amendola, Vincenzo

    2016-11-17

    Nanoparticles of hybrid organic-inorganic perovskites have attracted a great deal of attention due to their variety of optoelectronic properties, their low cost, and their easier integration into devices with complex geometry, compared with microcrystalline, thin-film, or bulk metal halides. Here we present a novel one-step synthesis of organolead bromide perovskite nanocrystals based on pulsed-laser irradiation in a liquid environment (PLIL). Starting from a bulk CHNHPbBr crystal, our PLIL procedure does not involve the use of high-boiling-point polar solvents or templating agents, and runs at room temperature. The resulting nanoparticles are characterized by high crystallinity and are completely free of any microscopic product or organic coating layer. We also demonstrate the straightforward inclusion of laser-generated perovskite nanocrystals in a polymeric matrix to form a nanocomposite with single- and two-photon luminescence properties.

  4. Preparation of high purity plutonium oxide for radiochemistry instrument calibration standards and working standards

    International Nuclear Information System (INIS)

    Wong, A.S.; Stalnaker, N.D.

    1997-04-01

    Due to the lack of suitable high level National Institute of Standards and Technology (NIST) traceable plutonium solution standards from the NIST or commercial vendors, the CST-8 Radiochemistry team at Los Alamos National Laboratory (LANL) has prepared instrument calibration standards and working standards from a well-characterized plutonium oxide. All the aliquoting steps were performed gravimetrically. When a 241 Am standardized solution obtained from a commercial vendor was compared to these calibration solutions, the results agreed to within 0.04% for the total alpha activity. The aliquots of the plutonium standard solutions and dilutions were sealed in glass ampules for long term storage

  5. thesis of high-purity carbon nanotubes over alumina and silica supported bimetallic catalysts

    Directory of Open Access Journals (Sweden)

    Sanja Ratković

    2009-10-01

    Full Text Available Carbon nanotubes (CNTs were synthesized by a catalytic chemical vapor deposition method (CCVD of ethylene over alumina and silica supported bimetallic catalysts based on Fe, Co and Ni. The catalysts were prepared by a precipitation method, calcined at 600 °C and in situ reduced in hydrogen flow at 700 °C. The CNTs growth was carried out by a flow the mixture of C2H4 and nitrogen over the catalyst powder in a horizontal oven. The structure and morphology of as-synthesized CNTs were characterized using SEM. The as-synthesized nanotubes were purified by acid and basic treatments in order to remove impurities such as amorphous carbon, graphite nanoparticles and metal catalysts. XRD and DTA/TG analyses showed that the amounts of by-products in the purified CNTs samples were reduced significantly. According to the observed results, ethylene is an active carbon source for growing high-density CNTs with high yield but more on alumina-supported catalysts than on their silica- supported counterparts. The last might be explained by SMSI formed in the case of alumina-supported catalysts, resulting in higher active phase dispersion.

  6. A simplified method for obtaining high-purity perchlorate from groundwater for isotope analyses.

    Energy Technology Data Exchange (ETDEWEB)

    vonKiparski, G; Hillegonds, D

    2011-04-04

    Investigations into the occurrence and origin of perchlorate (ClO{sub 4}{sup -}) found in groundwater from across North America have been sparse until recent years, and there is mounting evidence that natural formation mechanisms are important. New opportunities for identifying groundwater perchlorate and its origin have arisen with the utilization of improved detection methods and sampling techniques. Additionally, application of the forensic potential of isotopic measurements has begun to elucidate sources, potential formation mechanisms and natural attenuation processes. Procedures developed appear to be amenable to enable high precision stable isotopic analyses, as well as lower precision AMS analyses of {sup 36}Cl. Immediate work is in analyzing perchlorate isotope standards and developing full analytical accuracy and uncertainty expectations. Field samples have also been collected, and will be analyzed when final qa/qc samples are deemed acceptable.

  7. Preparation, purification and characterization of high purity multi-wall carbon nanotube

    Science.gov (United States)

    Morsy, Mohamed; Helal, Magdy; El-Okr, Mohamed; Ibrahim, Medhat

    2014-11-01

    Chemical vapor deposition (CVD) was optimized in order to prepare multi-wall carbon nanotubes (MWCNTs). Preparation of MWCNTs was achieved by the help of ferrocene as a catalyst with continuous flow of xylene. Morphology and structure of as grown and purified MWCNTs were characterized by Scanning Electron Microscope (SEM) and High-Resolution Transmission Electron Microscope (HRTEM). Energy Dispersive X-ray (EDX) spectra for the as grown MWCNTs confirm that the deposits are carbonaceous materials. XRD pattern of purified sample indicates that the Fe peaks at 44.6 and 50.9 have been decreased. This confirms that purification process is effectively reducing Fe component. Further qualitative information on the purification process are indicated and confirmed by the thermal analysis measurements. Finally, FTIR studies have been performed for the identification of the functional group attached on the surface of the MWCNTs. Collecting these results revealed that the optimized CVD is suitable for the production of MWCNTs.

  8. Chiral trialkylborane reducing agents. Preparation of 1-deuterio primary alcohols of high enantiomeric purity

    International Nuclear Information System (INIS)

    Midland, M.M.; Greer, S.; Tramontano, A.; Zderic, S.A.

    1979-01-01

    B-3-Pinanyl-9-borabicyclo[3.3.1]nonane (3-pinanyl-9-BBN, prepared from (+)-α-pinene and 9-BBN) is an effective chemical reagent for the asymmetric reduction of 1-deuterio aldehydes to chiral 1-deuterio primary alcohols. For example, benzaldehyde-1-d is reduced to pure (S)-(+)-benzyl-l-d alcohol. A deuterated reagent prepared from α-pinene and 9-BBN-9-d was found to reduce a variety of aromatic, aliphatic, and α,β-unsaturated aldehydes to the corresponding chiral primary 1-deuterio alcohols. In each case a large excess of the R enantiomer is formed. Steric factors seem to have little effect on the extent of asymmetric induction, but electron-donating para substituents on benzaldehyde slightly decrease the enantioselectivity of the reduction. A number of other chiral-9-BBN derivatives were investigated. A model is proposed to account for the high asymmetric inductions. 2 tables

  9. Mechanism of benzene hydroxylation by high-valent bare Fe(IV)=O2+: explicit electronic structure analysis.

    Science.gov (United States)

    Li, Ji-Lai; Zhang, Xiang; Huang, Xu-Ri

    2012-01-07

    The conversion of benzene to phenol by high-valent bare FeO(2+) was comprehensively explored using a density functional theory method. The conductor-like screen model (COSMO) was used to mimic the role of solvent effect with acetonitrile chosen as the solvent. Two radical mechanisms and one oxygen insertion mechanism were tested for this conversion. The first radical mechanism can also be named as the concerted mechanism in which the hydrogen-atom abstraction process is accomplished via a four-centered transition state. The second radical mechanism is initiated by a direct hydrogen-atom abstraction with a collinear C-H-O transition structure. It is actually the same as the well-accepted rebound mechanism for the C-H bond activation by heme and nonheme iron-oxo catalysts. The third is an oxygen insertion mechanism which is essentially an aromatic electrophilic attack leading to an arenium σ-complex intermediate. The formation of a precomplex with an η(4) coordinate environment in the first radical mechanism is energetically more favorable. However, the relatively lower activation energy barrier of the oxygen insertion mechanism compared to the radical ones makes it highly competitive if the Fe=O(2+) collides with benzene in the proper orientation. The detailed potential energy surfaces also indicate that the second radical mechanism, i.e., the benzene C-H bond activation through the rebound mechanism, is less favorable. This thorough theoretical study, especially the electronic structure analysis, may offer very important clues for understanding and studying C-H bond activation by iron-based catalysts and enzymatic reactions in protein active pockets.

  10. Some examples of industrial applications of ultra-high purity steels

    International Nuclear Information System (INIS)

    Bocquet, P.; Cheviet, A.; Varcin, E.

    1995-01-01

    In the last decade, the evolution and control of steelmaking practice have enabled drastic reductions to be made in the impurity content of low alloy steels (mainly S, P, O, N and H) and the resulting superclean steel products have seen their in-service behaviour greatly improved. The following examples concerning CLI products are presented : 1 - The reduction of S content by a factor of more than ten and the control of O content have considerably reduced the Hydrogen Induced Cracking (HIC) sensitivity of the C-Mn steel grades for the storage of oil and gas in sour environments. 2 - Superclean Ni Cr Mo V steel grades for turbine rotors shafts have a very low sensitivity to lower nose temper embrittlement. 3 - Thick (> 100 mm) plates or forgings in Mn Ni Mo steel grade used for nuclear pressure vessels welded by the electron beam process offer high toughness in fused areas when S + P are reduced to less than 30 ppm. 4 - Steel grades very close to pure iron have been developed to improve the performance of magnetic circuits in large accelerators. (orig.)

  11. 18F half-life measurement using a high-purity germanium detector

    International Nuclear Information System (INIS)

    Han, Jubong; Lee, K.B.; Park, T.S.; Lee, J.M.; Oh, P.J.; Lee, S.H.; Kang, Y.S.; Ahn, J.K.

    2012-01-01

    The half-life of 18 F has been measured using HPGe detectors with a 137 Cs reference source. The counting ratio of 511 keV γ-rays from 18 F to 622 keV γ-rays from 137 Cs was fitted for the half-life with a weighted least-square method. Uncertainties due to the systematic effects arising from the measurement of a high activity 18 F source were studied in detail. The half-life of 18 F was found to be (109.72±0.19) min. The result is in a good agreement with the recommended value of (109.728±0.019) min evaluated at the Laborotaire National Henri Becquerel (LNHB). - Highlights: ► The 18 F half-life was measured with a reference source and without it using HPGe detectors. ► We found the systematic effect ‘activity dynamic range effect’ by monitoring the counts of the reference source. ► This activity dynamic range effect was corrected by using the reference source method. ► The 18 F half-life using the reference source method was in a good agreement with the recommended value of LNHB.

  12. Corrosion of high purity copper as engineering barrier in deep geological repositories

    International Nuclear Information System (INIS)

    Ochoa, Maité; Rodríguez Martín, A.; Farina Silvia, B.

    2013-01-01

    Pure copper with oxygen content below 5 ppm (to minimize segregation at grain boundaries) and doped with phosphorus (to increase creep resistance) is the chosen material for the corrosion-resistant barrier of the High Level Radioactive 2 Wastecontainers in the Swedish and Finnish repository models. These models include the construction of the repository below the water table, which is a reducing environment in which copper has excellent resistance to general and localized corrosion in aqueous electrolytes. The aim of this work is contribute to determine the durability of the material, given that deep geological repositories of HLW are designed to ensure the protection of the environment for periods of hundreds of thousands years. As a first step in a more general analysis the effects of chloride, one of the main aggressive species of corrosion, are evaluated. To this purpose corrosion potential was determined and anodic polarization curves were performed in deaerated solutions varying the chloride concentration between 0.01 and 1M and the temperature between 30 and 90°C. Several electrochemical techniques were used: the evolution of corrosion potential was measured, anodic polarization curves were obtained and electrochemical impedance tests were performed. The analysis was complemented with microscopic observations of the type of corrosive attack, as well as determinations of the eventual corrosion products formed using Energy-Dispersive X-ray Analysis (EDS). Results show that the corrosion potential decreases with the increase of temperature and with the increase of chloride concentration. A correlation of the corrosion potential as a function of temperature and chloride concentration was obtained, with the purpose of making predictions in variable conditions.The current density increases both with temperature and with chloride concentration. A pitting potential is observed in certain conditions. (author)

  13. Microwave-Hydrothermal Synthesis and Characterization of High-Purity Nb Doped BaTiO3 Nanocrystals

    Directory of Open Access Journals (Sweden)

    A. Khanfekr

    2014-01-01

    Full Text Available The synthesis of Nb doped BaTiO3 has been investigated under Microwave-Hydrothermal (MH conditions in the temperature of 150°C for only 2 h using C16H36O4Ti, BaH2O2.8H2O and NbCl5 as Ba, Ti and  Nb sources, respectively.  Typical experiments performed on MH processing have not yet reported for Nb doped BaTiO3.  In the MH process, the formation of high purity nano tetragonal Nb-BaTiO3 was strongly enhanced. New hydrothermal method was used instead of the previous solid state reaction for the BaTiO3±Nb2O3 system. The new method uses high pressure to create nano dimension particles in a lower time and temperature. In case of the phase evolution studies, the XRD pattern measurements and Raman spectroscopy were performed. TEM and FE-SEM images were taken for the detailed analysis of the particle size, surface and morphology.  Synthesis of Nb doped BaTiO3 with the Microwave-hydrothermal provides an advantage of fast crystallization and reduced crystal size when compared to existing methods.

  14. Thermal conductivity, electrical resistivity, and Seebeck coefficient of high-purity chromium from 280 to 1000 K

    International Nuclear Information System (INIS)

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

    1977-01-01

    The thermal conductivity lambda, electrical resistivity rho, and Seebeck coefficient S of a high-purity Cr specimen (rho 273 /rho/sub 4.2/ = 380) were measured from 285 to 1000 K. The rho and S of two other Cr specimens (rho 273 /rho/sub 4.1/ = 380 and 58) were determined from 300 to 1300 K. The rho and S results from the three specimens are in excellent agreement, and all three properties agree to within experimental uncertainty with previous low-temperature results on the same specimens over the temperature range of overlap. Near T'/sub N/ (300--320 K), the present lambda results are within 0.7% of the previous data and indicate that lambdarho/T should be smooth to within 1%. At high temperature, the present lambda data are about 8% above those of Powell and Tye, but the ratios of lambdarho/T agree to within 2% up to 1000 K. These new data on pure Cr are compared to calculations from standard transport theory and to previous results from W and Mo

  15. Potential of hot water extraction of birch wood to produce high-purity dissolving pulp after alkaline pulping.

    Science.gov (United States)

    Borrega, Marc; Tolonen, Lasse K; Bardot, Fanny; Testova, Lidia; Sixta, Herbert

    2013-05-01

    The potential of hot water extraction of birch wood to produce highly purified dissolving pulp in a subsequent soda-anthraquinone pulping process was evaluated. After intermediate extraction intensities, pulps with low xylan content (3-5%) and high cellulose yield were successfully produced. Increasing extraction intensity further decreased the xylan content in pulp. However, below a xylan content of 3%, the cellulose yield dramatically decreased. This is believed to be due to cleavage of glycosidic bonds in cellulose during severe hot water extractions, followed by peeling reactions during alkaline pulping. Addition of sodium borohydride as well as increased anthraquinone concentration in the pulping liquor increased the cellulose yield, but had no clear effects on pulp purity and viscosity. The low intrinsic viscosity of pulps produced after severe extraction intensities and soda-anthraquinone pulping corresponded to the viscosity at the leveling-off degree of polymerization, suggesting that nearly all amorphous cellulose had been degraded. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Cyclotron production of high-purity 123I for medical applications via the 127I(p,5n)123Xe → 123I nuclear reaction

    International Nuclear Information System (INIS)

    Lagunas-Solar, M.C.

    1985-01-01

    The use of iodine-123 in nuclear medicine procedures is well documented in the scientific literature. Also, several methods for its production based on accelerator techniques have been described. Indirectly made 123 I via the 127 I(p,5n) 123 Xe → 123 I reaction produces 123 I of > 99.9% radionuclidic purity, with only 125 I ( 123 I production were developed at the University of California at Davis, where since 1974 the 76-in. isochronous cyclotron of the Crocker Nuclear Laboratory has been used for routine biweekly production of high-purity no-carrier-added 123 I

  17. Direct Production of (R)-3-Hydroxybutyric Acid of High Optical Purity by Halomonas sp. OITC1261 Under Aerobic conditions.

    Science.gov (United States)

    Yokaryo, Hiroto; Teruya, Morimi; Hanashiro, Ryuji; Goda, Masahiro; Tokiwa, Yutaka

    2018-02-01

    The chiral compound (R)-3-hydroxybutyric acid (R-3HB) has some important physiological functions in the human body and can also be applied as a functional material for industrial products. A novel Halomonas sp. OITC1261 isolated from a coastal sediment is selected for efficient production of R-3HB. This strain secreted R-3HB of high optical purity into the extracellular medium while maintaining poly(3-hydroxybutyric acid) (PHB) inside the microbial cell under aerobic conditions. There is a possibility that R-3HB is generated independently of PHB. Under aerobic cultivation, 58 g L -1 (0.65 g L -1  h -1 ) of R-3HB was produced simultaneously with 27 g L -1 (0.30 g L -1  h -1 ) of PHB. This direct production method of R-3HB contributes to the improvement of mass production technology. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Control of the Gas Flow in an Industrial Directional Solidification Furnace for Production of High Purity Multicrystalline Silicon Ingots

    Directory of Open Access Journals (Sweden)

    Lijun Liu

    2015-01-01

    Full Text Available A crucible cover was designed as gas guidance to control the gas flow in an industrial directional solidification furnace for producing high purity multicrystalline silicon. Three cover designs were compared to investigate their effect on impurity transport in the furnace and contamination of the silicon melt. Global simulations of coupled oxygen (O and carbon (C transport were carried out to predict the SiO and CO gases in the furnace as well as the O and C distributions in the silicon melt. Cases with and without chemical reaction on the cover surfaces were investigated. It was found that the cover design has little effect on the O concentration in the silicon melt; however, it significantly influences CO gas transport in the furnace chamber and C contamination in the melt. For covers made of metal or with a coating on their surfaces, an optimal cover design can produce a silicon melt free of C contamination. Even for a graphite cover without a coating, the carbon concentration in the silicon melt can be reduced by one order of magnitude. The simulation results demonstrate a method to control the contamination of C impurities in an industrial directional solidification furnace by crucible cover design.

  19. Development of the dislocation arrangement in high-purity Nb-34 at% Ta alloy single crystals deformed in tension

    International Nuclear Information System (INIS)

    Wasserbaech, W.

    1995-01-01

    The deformation behaviour and the dislocation arrangement of high-purity Nb-34 at% Ta alloy single crystals after tensile deformation at 330 K into different stages are studied by slip-line observations, Laue X-ray back-reflection, X-ray topography, and transmission electron microscopy (TEM). In stage I of the work-hardening curve, the dislocation arrangement consists predominantly of primary dislocations, which are clustered into bundles in the form of braids. Fine slip traces on the surface of the specimens show that the slip proceeds homogeneously in the whole volume of the crystal. Stage II, which is a characteristic property of f.c.c. metals, is missing. Instead, the experimental findings suggest that a gradual transition occurs from stage I into stage III. The transition region is characterized by a pronounced formation of dislocation sheets approximately parallel to the primary slip plane. The dislocation sheets are crossed grids of primary and secondary dislocations and occur in pairs. The secondary slip necessary for the formation of the dislocation sheets is found to occur in the direction favoured by the applied shear stress. In spite of the different dislocation arrangements, the slip processes in stage I and stage III seem to be essentially the same. In both cases the macroscopic slip proceeds by glide of primary dislocations over large slip distances, whereby the plane that carries the maximum resolved shear stress (MRSS) is the active macroscopic slip plane. (orig.)

  20. High phase-purity 1T'-MoS2- and 1T'-MoSe2-layered crystals.

    Science.gov (United States)

    Yu, Yifu; Nam, Gwang-Hyeon; He, Qiyuan; Wu, Xue-Jun; Zhang, Kang; Yang, Zhenzhong; Chen, Junze; Ma, Qinglang; Zhao, Meiting; Liu, Zhengqing; Ran, Fei-Rong; Wang, Xingzhi; Li, Hai; Huang, Xiao; Li, Bing; Xiong, Qihua; Zhang, Qing; Liu, Zheng; Gu, Lin; Du, Yonghua; Huang, Wei; Zhang, Hua

    2018-04-02

    Phase control plays an important role in the precise synthesis of inorganic materials, as the phase structure has a profound influence on properties such as conductivity and chemical stability. Phase-controlled preparation has been challenging for the metallic-phase group-VI transition metal dichalcogenides (the transition metals are Mo and W, and the chalcogens are S, Se and Te), which show better performance in electrocatalysis than their semiconducting counterparts. Here, we report the large-scale preparation of micrometre-sized metallic-phase 1T'-MoX 2 (X = S, Se)-layered bulk crystals in high purity. We reveal that 1T'-MoS 2 crystals feature a distorted octahedral coordination structure and are convertible to 2H-MoS 2 following thermal annealing or laser irradiation. Electrochemical measurements show that the basal plane of 1T'-MoS 2 is much more active than that of 2H-MoS 2 for the electrocatalytic hydrogen evolution reaction in an acidic medium.

  1. Design, construction, and operation of a laboratory scale reactorfor the production of high-purity, isotopically enriched bulksilicon

    Energy Technology Data Exchange (ETDEWEB)

    Ager III, J.W.; Beeman, J.W.; Hansen, W.L.; Haller, E.E.

    2004-12-20

    The design and operation of a recirculating flow reactor designed to convert isotopically enriched silane to polycrystalline Si with high efficiency and chemical purity is described. The starting material is SiF{sub 4}, which is enriched in the desired isotope by a centrifuge method and subsequently converted to silane. In the reactor, the silane is decomposed to silicon on the surface of a graphite starter rod (3 mm diameter) heated to 700-750 C. Flow and gas composition (0.3-0.5% silane in hydrogen) are chosen to minimize the generation of particles by homogeneous nucleation of silane and to attain uniform deposition along the length of the rod. Growth rates are 5 {micro}m/min, and the conversion efficiency is greater than 95%. A typical run produces 35 gm of polycrystalline Si deposited along a 150 mm length of the rod. After removal of the starter rod, dislocation-free single crystals are formed by the floating zone method. Crystals enriched in all 3 stable isotopes of Si have been made: {sup 28}Si (99.92%), {sup 29}Si (91.37%), and {sup 30}Si (88.25%). Concentrations of electrically active impurities (P and B) are as low as mid-10{sup 13} cm{sup -3}. Concentrations of C and O lie below 10{sup 16} and 10{sup 15} cm{sup -3}, respectively.

  2. Study of corrosion processes on Al-AA 6061 crevices immersed in high purity water and sodium citrate solution

    International Nuclear Information System (INIS)

    Rodriguez, Sebastian A.; Haddad, Roberto; Lanzani, Liliana A.

    2004-01-01

    An experimental approach has been developed to study the corrosion behavior of artificial crevices manufactured with high purity aluminum and AA 6061 alloy, immersed in dematerialised water and sodium citrate solution (96,5 μS/cm). Alkaline attack was found on the surrounding of iron rich particles in the external zone of the crevice, as a result of localized oxygen reduction reaction on these sites. This attack was not observed in the zone inside the crevice. Study of the phase Mg 2 Si by EDS allowed establishing that there is not preferential dissolution inside the crevice. The formation of a stable and non-soluble complex between Al and citrate anion inhibited the production of Al(OH) 3 precipitate, which was observed on the surface of specimens immersed in pure water. Investigations of the aluminum oxide evolution on AA 6061 surfaces in water showed that it was composed by two layers: an internal one made of Bohemite and an external one in direct contact with the water, with a Bayerite structure. The surface analysis was accomplished using XR, OM and SEM techniques. (author) [es

  3. Production of High-Purity Anhydrous Nickel(II Perrhenate for Tungsten-Based Sintered Heavy Alloys

    Directory of Open Access Journals (Sweden)

    Katarzyna Leszczyńska-Sejda

    2017-04-01

    Full Text Available This paper presents a method for the production of high-purity anhydrous nickel(II perrhenate. The method comprises sorption of nickel(II ions from aqueous nickel(II nitrate solutions, using strongly acidic C160 cation exchange resin, and subsequent elution of sorbed nickel(II ions using concentrated perrhenic acid solutions. After the neutralization of the resulting rhenium-nickel solutions, hydrated nickel(II perrhenate is then separated and then dried at 160 °C to obtain the anhydrous form. The resulting compound is reduced in an atmosphere of dissociated ammonia in order to produce a Re-Ni alloy powder. This study provides information on the selected properties of the resulting Re-Ni powder. This powder was used as a starting material for the production of 77W-20Re-3Ni heavy alloys. Microstructure examination results and selected properties of the produced sintered heavy alloys were compared to sintered alloys produced using elemental W, Re, and Ni powders. This study showed that the application of anhydrous nickel(II perrhenate in the production of 77W-20Re-3Ni results in better properties of the sintered alloys compared to those made from elemental powders.

  4. Effects of thermal history and irradiation on the dc conductivity of high purity GeO2 glasses

    International Nuclear Information System (INIS)

    Magruder, R.H.

    1985-01-01

    The dc electrical properties of a series of high purity GeO 2 glasses fused and equilibrated at various temperatures (T phi) in air were measured. T phi ranged from 1350 0 C to 1690 0 C. The charge carriers are shown to be the Na ions. The mobility is found to obey an Arrhenius function with enthalpy of activation of approximately 1.01 eV in the as-quenched state for all T phi's. The changes observed in the mobilities of the Na ions for the various T phi's are suggested to be caused by changes in the configurational coordinates of the average interstitial sites through which the Na ion moves with changes in T phi. These changes are manifested in the entropy of activation. Subsequent annealing treatments at 420 0 C (15 0 below the Littleton softening point) for the times observed in these experiments do not change the general behavior of the mobility with T phi even though they do change the observed values of mobilities. These changes are suggested to result from thermal compaction changing the average well structure through which the Na ion moves. The γ irradiation of these glasses causes a decrease in the mobility of the Na ion for all T phi samples. The mobilities decreases with increasing dose. These decreases in mobilities are suggested to be caused by radiation induced compaction and by change of defect concentrations. These two processes result through relaxation processes and coulombic forces in changes in the average well structure

  5. Genome sequence of the thermophilic strain Bacillus coagulans 2-6, an efficient producer of high-optical-purity L-lactic acid.

    Science.gov (United States)

    Su, Fei; Yu, Bo; Sun, Jibin; Ou, Hong-Yu; Zhao, Bo; Wang, Limin; Qin, Jiayang; Tang, Hongzhi; Tao, Fei; Jarek, Michael; Scharfe, Maren; Ma, Cuiqing; Ma, Yanhe; Xu, Ping

    2011-09-01

    Bacillus coagulans 2-6 is an efficient producer of lactic acid. The genome of B. coagulans 2-6 has the smallest genome among the members of the genus Bacillus known to date. The frameshift mutation at the start of the d-lactate dehydrogenase sequence might be responsible for the production of high-optical-purity l-lactic acid.

  6. The Production of High Purity Phycocyanin by Spirulina platensis Using Light-Emitting Diodes Based Two-Stage Cultivation.

    Science.gov (United States)

    Lee, Sang-Hyo; Lee, Ju Eun; Kim, Yoori; Lee, Seung-Yop

    2016-01-01

    Phycocyanin is a photosynthetic pigment found in photosynthetic cyanobacteria, cryptophytes, and red algae. In general, production of phycocyanin depends mainly on the light conditions during the cultivation period, and purification of phycocyanin requires expensive and complex procedures. In this study, we propose a new two-stage cultivation method to maximize the quantitative content and purity of phycocyanin obtained from Spirulina platensis using red and blue light-emitting diodes (LEDs) under different light intensities. In the first stage, Spirulina was cultured under a combination of red and blue LEDs to obtain the fast growth rate until reaching an absorbance of 1.4-1.6 at 680 nm. Next, blue LEDs were used to enhance the concentration and purity of the phycocyanin in Spirulina. Two weeks of the two-stage cultivation of Spirulina yielded 1.28 mg mL(-1) phycocyanin with the purity of 2.7 (OD620/OD280).

  7. Mapping bare soil in South West Wales, UK, using high resolution colour infra-red aerial photography for water quality and flood risk management applications

    Science.gov (United States)

    Sykes, Helena; Neale, Simon; Coe, Sarah

    2016-04-01

    Natural Resources Wales is a UK government body responsible for environmental regulation, among other areas. River walks in Water Framework Directive (WFD) priority catchments in South West Wales, UK, identified soil entering water courses due to poaching and bank erosion, leading to deterioration in the water quality and jeopardising the water quality meeting legal minimum standards. Bare soil has also been shown to cause quicker and higher hydrograph peaks in rural catchments than if those areas were vegetated, which can lead to flooding of domestic properties during peak storm flows. The aim was to target farm visits by operational staff to advise on practices likely to improve water quality and to identify areas where soft engineering solutions such as revegetation could alleviate flood risk in rural areas. High resolution colour-infrared aerial photography, 25cm in the three colour bands and 50cm in the near infrared band, was used to map bare soil in seven catchments using supervised classification of a five band stack including the Normalised Difference Vegetation Index (NDVI). Mapping was combined with agricultural land use and field boundary data to filter out arable fields, which are supposed to bare soil for part of their cycle, and was very successful when compared to ground truthing, with the exception of silage fields which contained sparse, no or unproductive vegetation at the time the imagery was acquired leading to spectral similarity to bare soil. A raindrop trace model was used to show the path sediment from bare soil areas would take when moving through the catchment to a watercourse, with hedgerows inserted as barriers following our observations from ground truthing. The findings have been used to help farmers gain funding for improvements such as fencing to keep animals away from vulnerable river banks. These efficient and automated methods can be rolled out to more catchments in Wales and updated using aerial imagery acquired more recently to

  8. Unique low-molecular-weight lignin with high purity extracted from wood by deep eutectic solvents (DES): a source of lignin for valorization

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Vasco, Carlos; Ma, Ruoshui; Quintero, Melissa; Guo, Mond; Geleynse, Scott; Ramasamy, Karthikeyan K.; Wolcott, Michael; Zhang, Xiao

    2016-01-01

    This paper reports a new method of applying Deep Eutectic Solvents (DES) for extracting lignin from woody biomass with high yield and high purity. DES mixtures prepared from Choline Chloride (ChCl) and four hydrogen-bond donors–acetic acid, lactic acid, levulinic acid and glycerol–were evaluated for treatment of hardwood (poplar) and softwood (D. fir). It was found that these DES treatments can selectively extract a significant amount of lignin from wood with high yields: 78% from poplar and 58% from D. fir. The extracted lignin has high purity (95%) with unique structural properties. We discover that DES can selectively cleave ether linkages in wood lignin and facilitate lignin removal from wood. The mechanism of DES cleavage of ether bonds between phenylpropane units was investigated. The results from this study demonstrate that DES is a promising solvent for wood delignification and the production of a new source of lignin with promising potential applications.

  9. Preparation of high purity nickel film from industrial effluent by the distribution of charge over microelectrodes using newly designed free electrolytic diffusion approach

    International Nuclear Information System (INIS)

    Ahmed, Sheikh Asrar; Qadir, Muhammad Abdul; Zafar, Muhammad Nadeem; Hussain, Ishtiaq; Tufail, Shahid; Rashid, Saima; Shah, Hamid Ali

    2008-01-01

    The present work deals with the development of a newly designed free electrolytic diffusion approach (the distribution of charge over microelectrodes) for the purification of metals and was successfully applied for the purification of nickel from the industrial effluent containing high proportion of nickel. Atomic absorption spectrophotometer (AAS) analyzed the purified nickel deposited on working microelectrodes. The results obtained show that the purity of nickel was enhanced from 95% to 99.9% with traces of copper etc. It was concluded that distribution of charge over the microcathodes at a rate of 50 cycles per second (cps) shows better results for the production of high purity (HP) nickel as compared to 25 cycles per second (cps)

  10. Preparation of high purity nickel film from industrial effluent by the distribution of charge over microelectrodes using newly designed free electrolytic diffusion approach

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Sheikh Asrar; Qadir, Muhammad Abdul [Institute of Chemistry, University of the Punjab, Lahore, 54590 (Pakistan); Zafar, Muhammad Nadeem [Institute of Chemistry, University of the Punjab, Lahore, 54590 (Pakistan)], E-mail: znadeempk@yahoo.com; Hussain, Ishtiaq [Institute of Chemistry, University of the Punjab, Lahore, 54590 (Pakistan); Tufail, Shahid [PCSIR Laboratories Complex, Feroz pur Road, Lahore (Pakistan); Rashid, Saima; Shah, Hamid Ali [Institute of Chemistry, University of the Punjab, Lahore, 54590 (Pakistan)

    2008-09-15

    The present work deals with the development of a newly designed free electrolytic diffusion approach (the distribution of charge over microelectrodes) for the purification of metals and was successfully applied for the purification of nickel from the industrial effluent containing high proportion of nickel. Atomic absorption spectrophotometer (AAS) analyzed the purified nickel deposited on working microelectrodes. The results obtained show that the purity of nickel was enhanced from 95% to 99.9% with traces of copper etc. It was concluded that distribution of charge over the microcathodes at a rate of 50 cycles per second (cps) shows better results for the production of high purity (HP) nickel as compared to 25 cycles per second (cps)

  11. High Cubic-Phase Purity InN on MgO (001) Using Cubic-Phase GaN as a Buffer Layer

    International Nuclear Information System (INIS)

    Sanorpim, S.; Kuntharin, S.; Parinyataramas, J.; Yaguchi, H.; Iwahashi, Y.; Orihara, M.; Hijikata, Y.; Yoshida, S.

    2011-01-01

    High cubic-phase purity InN films were grown on MgO (001) substrates by molecular beam epitaxy with a cubic-phase GaN buffer layer. The cubic phase purity of the InN grown layers has been analyzed by high resolution X-ray diffraction, μ-Raman scattering and transmission electron microscopy. It is evidenced that the hexagonal-phase content in the InN overlayer much depends on hexagonal-phase content in the cubic-phase GaN buffer layer and increases with increasing the hexagonal-phase GaN content. From Raman scattering measurements, in addition, the InN layer with lowest hexagonal component (6%), only Raman characteristics of cubic TO InN and LO InN modes were observed, indicating a formation of a small amount of stacking faults, which does not affect on vibrational property.

  12. An indirect sequential determination of phosphorus and arsenic in high-purity tungsten and its compounds by atomic-absorption spectrophotometry

    International Nuclear Information System (INIS)

    Tekula-Buxbaum, P.

    1981-01-01

    An indirect atomic-absorption spectrophotometric method based on selective extraction of heteropolymolybdic acids has been developed for determination of small quantities of P and As in high-purity tungsten metal and tungsten compounds. The method is suitable for determination of 5-100 ppm of phosphorus and arsenic. The relative standard deviation is 38-5% for P and 31-3% for As, depending on the concentrations. (auth.)

  13. Effects of 600 MeV proton irradiation on nucleation and growth of precipitates and helium bubbles in a high-purity Al-Mg-Si alloy

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Leffers, Torben; Victoria, M.

    1986-01-01

    Solution treated specimens of a high-purity Al-0.75%Mg-0.42%Si alloy were irradiated with 600 MeV protons at 150 and 240°C to a dose level of 0.47 and 0.55 dpa, respectively. Mg2Si-type precipitates formed during irradiation at 150 and 240°C; at 240°C, however, a large number of precipitates seem...

  14. Super high-rate fabrication of high-purity carbon nanotube aerogels from floating catalyst method for oil spill cleaning

    Science.gov (United States)

    Khoshnevis, Hamed; Mint, Sandar Myo; Yedinak, Emily; Tran, Thang Q.; Zadhoush, Ali; Youssefi, Mostafa; Pasquali, Matteo; Duong, Hai M.

    2018-02-01

    In this study, we apply an advanced floating catalyst method to fabricate carbon nanotube (CNT) aerogels at super high deposition rate for oil spill cleaning. The aerogels consist of 3D porous network of stacking double-walled CNT bundles with low catalyst impurity (9%) and high thermal stability (650 °C). With high porosity, surface areas, and water contact angles, the CNT aerogels exhibit a high oil adsorption of up to 107 g/g and good reusability of up to four adsorption-burning cycles. This work suggests that the lightweight, porous, and super hydrophobic CNT aerogels can be promising sorbent materials for environmental applications.

  15. Synthesis of high-purity Li{sub 8}ZrO{sub 6} powder by solid state reaction under hydrogen atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Shin-mura, Kiyoto; Otani, Yu; Ogawa, Seiya [Course of Mechanical Engineering, Graduate School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Niwa, Eiki; Hashimoto, Takuya [Department of Physics, College of Humanities and Sciences, Nihon University, 3-8-1 Sakurajousui, Setagaya-ku, Tokyo 156-8550 (Japan); Hoshino, Tsuyoshi [Breeding Functional Materials Development Group, Department of Blanket Systems Research, Rokkasho Fusion Institute, Sector of Fusion Research and Development, Japan Atomic Energy Agency, 2-166 Obuchi, Omotedate, Rokkasho-mura, Kamikita-gun, Aomori 039-3212 (Japan); Sasaki, Kazuya, E-mail: k_sasaki@tokai-u.ac.jp [Course of Mechanical Engineering, Graduate School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Department of Prime Mover Engineering, School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan)

    2016-11-01

    Highlights: • A fine pure Li{sub 8}ZrO{sub 6} powder was synthesized by using Li{sub 2}CO{sub 3} and ZrO{sub 2} via a solid state reaction. • Influences on the purity of product powder, lattice defect, and crystal orientation were revealed. • The suitable synthesis conditions of the fine and high purity Li{sub 8}ZrO{sub 6} powder were found. • The reaction process of the synthesis of Li{sub 8}ZrO{sub 6} was estimated. - Abstract: Li{sub 8}ZrO{sub 6} contains a large amount of Li and has a significant potential as a tritium breeder. However, few syntheses of fine-grain, high-purity Li{sub 8}ZrO{sub 6} powder have been reported. In this study, a high-purity powder of Li{sub 8}ZrO{sub 6} was synthesized by solid state reaction under hydrogen atmosphere combined with an effective lithium source and a suitable initial Li:Zr molar ratio. Mixed powders of Li{sub 2}CO{sub 3} and ZrO{sub 2} were fired at around 630 °C in H{sub 2} for several hours and several firing cycles. The low firing temperature inhibited the vaporization of Li during the heating, so that excessive amounts of Li were not needed for the synthesis, and the Li:Zr ratio in the starting material was 10:1 (mol:mol). In this synthesis, Li{sub 2}O was generated via the decomposition of Li{sub 2}CO{sub 3} during firing in H{sub 2}, and reacted with ZrO{sub 2} to form Li{sub 6}Zr{sub 2}O{sub 7}, which reacted with itself to form Li{sub 8}ZrO{sub 6}.

  16. Certification of caffeine reference material purity by ultraviolet/visible spectrophotometry and high-performance liquid chromatography with diode-array detection as two independent analytical methods.

    Science.gov (United States)

    Shehata, A B; Rizk, M S; Rend, E A

    2016-10-01

    Caffeine reference material certified for purity is produced worldwide, but no research work on the details of the certification process has been published in the literature. In this paper, we report the scientific details of the preparation and certification of pure caffeine reference materials. Caffeine was prepared by extraction from roasted and ground coffee by dichloromethane after heating in deionized water mixed with magnesium oxide. The extract was purified, dried, and bottled in dark glass vials. Stratified random selection was applied to select a number of vials for homogeneity and stability studies, which revealed that the prepared reference material is homogeneous and sufficiently stable. Quantification of caffeine purity % was carried out using a calibrated UV/visible spectrophotometer and a calibrated high-performance liquid chromatography with diode-array detection method. The results obtained from both methods were combined to drive the certified value and its associated uncertainty. The certified value of the reference material purity was found to be 99.86% and its associated uncertainty was ±0.65%, which makes the candidate reference material a very useful calibrant in food and drug chemical analysis. Copyright © 2016. Published by Elsevier B.V.

  17. Application of high-speed counter-current chromatography coupled with high-performance liquid chromatography-diode array detection for the preparative isolation and purification of hyperoside from Hypericum perforatum with online purity monitoring.

    Science.gov (United States)

    Zhou, Tingting; Chen, Bin; Fan, Guorong; Chai, Yifeng; Wu, Yutian

    2006-05-26

    Following preparative isolation and purification by high-speed counter-current chromatography (HSCCC), the collected fractions were generally analyzed by high-performance liquid chromatography (HPLC) to determine the relative purities of each fraction. Our paper reports for the first time a preparative isolation-purity detection hyphenated system: online coupling of HSCCC with high-performance liquid chromatography-diode array detection (HSCCC-HPLC-DAD). The introduction of online purity analysis in HSCCC has dramatically improved the efficiency of this technique by overcoming the drawbacks of post analysis in HSCCC isolation. The effluent from the outlet of HSCCC was splitted into two parts: one was collected, while the other was introduced directly into an HPLC-DAD system for purity analysis through a switch valve. Therefore, the purities of the obtained fractions from HSCCC were monitored, and fractions with high purities were collected. This strategy has been successfully demonstrated with the preparative isolation and purification of hyperoside from Hypericum perforatum (St. Jone's Wort); a model of TBE-300A HSCCC was used to isolate and separate hyperoside from H. perforatum with a two-phase solvent system composed of ethyl acetate-ethanol-water at the volume ratio of 5:1:5 (v/v) using online detection technique. The isolation was done in less than 3.5 h, and a total of 83.0-mg hyperoside at over 99.0% purity was yielded from 300 mg of the partially purified extract. This new strategy possesses general utility in the preparation of bioactive compounds from traditional Chinese medicine (TCM).

  18. Measurement of the high-field Q-drop in a high-purity large-grain niobium cavity for different oxidation processes

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi; Kneisel, Peter; gurevich, alex

    2007-06-01

    The most challenging issue for understanding the performance of superconducting radio-frequency (rf) cavities made of high-purity (residual resistivity ratio > 200) niobium is due to a sharp degradation (“Q-drop”) of the cavity quality factor Q0(Bp) as the peak surface magnetic field (Bp) exceeds about 90 mT, in the absence of field emission. In addition, a low-temperature (100 – 140 C) “in-situ” baking of the cavity was found to be beneficial in reducing the Q-drop. In this contribution, we present the results from a series of rf tests at 1.7 K and 2.0 K on a single-cell cavity made of high-purity large (with area of the order of few cm2) grain niobium which underwent various oxidation processes, after initial buffered chemical polishing, such as anodization, baking in pure oxygen atmosphere and baking in air up to 180 °C, with the objective of clearly identifying the role of oxygen and the oxide layer on the Q-drop. During each rf test a temperature mapping system allows measuring the local temperature rise of the cavity outer surface due to rf losses, which gives information about the losses location, their field dependence and space distribution. The results confirmed that the depth affected by baking is about 20 – 30 nm from the surface and showed that the Q-drop did not re-appear in a previously baked cavity by further baking at 120 °C in pure oxygen atmosphere or in air up to 180 °C. These treatments increased the oxide thickness and oxygen concentration, measured on niobium samples which were processed with the cavity and were analyzed with Transmission Electron Microscope (TEM) and Secondary Ion Mass Spectroscopy (SIMS). Nevertheless, the performance of the cavity after air baking at 180 °C degraded significantly and the temperature maps showed high losses, uniformly distributed on the surface, which could be completely recovered only by a post-purification treatment at 1250 °C. A statistic of the position of the “hot-spots” on the

  19. A study on the influence of trace elements (C, S, B, Al, N) on the hot ductility of the high purity austenitic alloy Fe-Ni 36% (INVAR)

    Energy Technology Data Exchange (ETDEWEB)

    Simonetta-Perrot, M.T.

    1994-11-01

    In order to study the damage mechanisms leading to the ductility decrease of the Invar alloy at 600 C, a high-purity Fe-Ni 36% sample has been doped with trace elements with the purpose of identifying the role of sulfur, sulfur with Al N or B N precipitates and sulfur with boron, on the ductility, the failure modes, the intergranular damage and the plastic deformation mechanisms prior to failure. A new AES segregation quantification method has been used to study the kinetics and thermodynamics of intergranular and surface segregations and determine the relation between sulfur segregation and grain joint fragility. refs., figs., tabs.

  20. Preparation of High Purity, High Molecular-Weight Chitin from Ionic Liquids for Use as an Adsorbate for the Extraction of Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Robin [Univ. of Alabama, Tuscaloosa, AL (United States)

    2013-12-21

    Ensuring a domestic supply of uranium is a key issue facing the wider implementation of nuclear power. Uranium is mostly mined in Kazakhstan, Australia, and Canada, and there are few high-grade uranium reserves left worldwide. Therefore, one of the most appealing potential sources of uranium is the vast quantity dissolved in the oceans (estimated to be 4.4 billion tons worldwide). There have been research efforts centered on finding a means to extract uranium from seawater for decades, but so far none have resulted in an economically viable product, due in part to the fact that the materials that have been successfully demonstrated to date are too costly (in terms of money and energy) to produce on the necessary scale. Ionic Liquids (salts which melt below 100{degrees}C) can completely dissolve raw crustacean shells, leading to recovery of a high purity, high molecular weight chitin powder and to fibers and films which can be spun directly from the extract solution suggesting that continuous processing might be feasible. The work proposed here will utilize the unprecedented control this makes possible over the chitin fiber a) to prepare electrospun nanofibers of very high surface area and in specific architectures, b) to modify the fiber surfaces chemically with selective extractant capacity, and c) to demonstrate their utility in the direct extraction and recovery of uranium from seawater. This approach will 1) provide direct extraction of chitin from shellfish waste thus saving energy over the current industrial process for obtaining chitin; 2) allow continuous processing of nanofibers for very high surface area fibers in an economical operation; 3) provide a unique high molecular weight chitin not available from the current industrial process, leading to stronger, more durable fibers; and 4) allow easy chemical modification of the large surface areas of the fibers for appending uranyl selective functionality providing selectivity and ease of stripping. The

  1. Preparation of High Purity, High Molecular-Weight Chitin from Ionic Liquids for Use as an Adsorbate for the Extraction of Uranium from Seawater

    International Nuclear Information System (INIS)

    Rogers, Robin

    2013-01-01

    Ensuring a domestic supply of uranium is a key issue facing the wider implementation of nuclear power. Uranium is mostly mined in Kazakhstan, Australia, and Canada, and there are few high-grade uranium reserves left worldwide. Therefore, one of the most appealing potential sources of uranium is the vast quantity dissolved in the oceans (estimated to be 4.4 billion tons worldwide). There have been research efforts centered on finding a means to extract uranium from seawater for decades, but so far none have resulted in an economically viable product, due in part to the fact that the materials that have been successfully demonstrated to date are too costly (in terms of money and energy) to produce on the necessary scale. Ionic Liquids (salts which melt below 100 deg C) can completely dissolve raw crustacean shells, leading to recovery of a high purity, high molecular weight chitin powder and to fibers and films which can be spun directly from the extract solution suggesting that continuous processing might be feasible. The work proposed here will utilize the unprecedented control this makes possible over the chitin fiber a) to prepare electrospun nanofibers of very high surface area and in specific architectures, b) to modify the fiber surfaces chemically with selective extractant capacity, and c) to demonstrate their utility in the direct extraction and recovery of uranium from seawater. This approach will 1) provide direct extraction of chitin from shellfish waste thus saving energy over the current industrial process for obtaining chitin; 2) allow continuous processing of nanofibers for very high surface area fibers in an economical operation; 3) provide a unique high molecular weight chitin not available from the current industrial process, leading to stronger, more durable fibers; and 4) allow easy chemical modification of the large surface areas of the fibers for appending uranyl selective functionality providing selectivity and ease of stripping. The resulting

  2. The Globe laid bare

    CERN Multimedia

    Fortunati, Lucien

    2015-01-01

    If you’re at CERN at the moment, you will certainly have noticed the work under way on the Globe. The structure, which has been in pride of place opposite the Laboratory for over ten years, has never been so completely laid bare. But, as we explained in a previous article (see here), it is all for a good cause. The Globe is built entirely from wood and certain parts of it need to be replaced.

  3. Development of Ultra-high Purity (UHP) Fe-Based Alloys with High Creep and Oxidation Resistance for A-USC Technology

    Science.gov (United States)

    Hamdani, Fethi; Das, Nishith K.; Shoji, Tetsuo

    2018-03-01

    The design of ultra-high purity (UHP) Fe-based model alloys for advanced ultra-supercritical (A-USC) technology is attempted in this work. Creep testing has been performed in air at 700 °C and a stress level of 150 MPa. Analysis of the fracture surface and cross section of the crept specimen was performed. To evaluate the oxidation resistance in A-USC conditions, oxidation testing was performed in supercritical water (SCW) at 700 °C and 25 MPa. Weight gain (WG) measurements and meticulous characterization of the oxide scale were carried out. Based on thermodynamics and density functional theory calculations, some reactive elements in the Fe-Cr-Ni system were designated to promote precipitation strengthening and to improve the hydrogen-accelerated oxidation resistance. The addition of a 2 wt pct Mo into Fe-22Cr-22Ni-0.6Nb wt pct-based matrix did not significantly improve the creep resistance. The addition of 0.26 wt pct Zr coupled with cold working was effective for improving creep properties. The Mo-modified model alloy showed almost the same WG value as SUS310, while the Zr-modified alloy showed a higher WG value. Meanwhile, a Cr-enriched continuous oxide layer was formed at the oxidation front of the Zr-modified alloy and SUS310S after exposure to SCW conditions.

  4. Obtention of high purity silica from the flotation waste of itabiritic ore; Obtencao de silica de elevada pureza a partir do rejeito de flotacao de um minerio itabiritico

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Polyana Fabricia Fernandes

    2016-10-01

    Banded iron formations are exploited as iron mineral in 'Quadrilatero Ferrifero' of Minas Gerais (MG) State, Brazil. About half of the amount of extracted material becomes tailings, which are stored in tailing dams or used for filling mining pits. Tens of thousands of tons are generated daily in operating mines in this region, causing concern about the environmental liabilities, and costs to manage the tailing dams. Miners are committed to finding uses for these wastes in other productive chains. This thesis aimed to obtain high purity silica from the flotation tailings of banded iron formations using classical techniques for ore processing, such as particle size classification and magnetic separation, followed by hydrometallurgical leaching, also alkaline fusion and chemical precipitation. The tailings samples was collected in the tailings dam of Peak Mine operated by Vale A.S., in Itabirito – MG. This sample had initially 33.4% by weight SiO{sub 2}, 57.4% wt Fe{sub 2}O{sub 3} and 8.31% wt Al{sub 2}O{sub 3}. After desliming for disposal of the fine particles (-37μm) the composition was 68.0% SiO{sub 2}, 31.4% Fe{sub 2}O{sub 3} and 0.50% Al{sub 2}O{sub 3}. After magnetic separation, the composition was 93.8% SiO{sub 2}, 1.16% Fe{sub 2}O{sub 3} and 3.80% Al{sub 2}O{sub 3}. After acid leaching l or digestion to remove impurities, it was possible to obtain silica with 98% purity. The fusion with sodium hydroxide, followed by alkaline leaching of sodium silicate and silica precipitation gave purities of about 99.5%. Values even higher may be possible with optimization of the parameters of alkaline fusion or by repeating the process from the product with purity of 99.5%. The iron oxide content and the aluminum main contaminants were 0.01% and 0.07%, respectively. Amorphous silica was obtained with high specific surface (322 m{sup 2}/g) and particle size less than 200 nm. Depending on the application, a control should be made for the impurities, such as

  5. An efficient method for high-purity anthocyanin isomers isolation from wild blueberries and their radical scavenging activity.

    Science.gov (United States)

    Chorfa, Nasima; Savard, Sylvain; Belkacemi, Khaled

    2016-04-15

    An efficient process for the purification of anthocyanin monomeric isomers from wild blueberries of Lake Saint-Jean region (Quebec, Canada) was developed and easy scalable at industrial purpose. The blueberries were soaked in acidified ethanol, filtered, and the filtrate was cleaned by solid phase extraction using silica gel C-18 and DSC-SCX cation-exchange resin. Anthocyanin-enriched elutes (87 wt.%) were successfully fractionated by preparative liquid chromatography. The major anthocyanins mono-galactoside, -glucoside and -arabinoside isomers of delphinidin, cyanidin, petunidin, peonidin and malvidin were isolated with a purity up to 100% according to their LC-MS and (1)H NMR spectra. The oxygen radical absorbance capacity (ORAC) of the obtained pure anthocyanins was evaluated. Delphinidin-3-galactoside has the highest capacity (13.062 ± 2.729 μmol TE/μmol), and malvidin-3-glucoside the lowest (0.851 ± 0.032 μmol TE/μmol). A mechanistic pathway preview is suggested for the anthocyanins scavenging free radical activity by hydrogen transfer. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Jerusalem artichoke powder: a useful material in producing high-optical-purity l-lactate using an efficient sugar-utilizing thermophilic Bacillus coagulans strain.

    Science.gov (United States)

    Wang, Limin; Xue, Zhangwei; Zhao, Bo; Yu, Bo; Xu, Ping; Ma, Yanhe

    2013-02-01

    Jerusalem artichoke is a low-requirement crop, which does not interfere with food chain, and is a promising carbon source for industrial fermentation. Microbial conversion of such a renewable raw material to useful products, such as lactic acid, is an important objective in industrial biotechnology. In this study, high-optical-purity l-lactate was efficiently produced from the hydrolysates of Jerusalem artichoke powder by a thermophilic bacterium, Bacillus coagulans XZL4. High l-lactate production (134gl(-1)) was obtained using 267gl(-1) Jerusalem artichoke powder (total reducing sugars of 140gl(-1)) and 10gl(-1) of corn steep powder in fed-batch fermentation, with an average productivity of 2.5gl(-1)h(-1) and a yield of 0.96gg(-1) reducing sugars. The final product optical purity is 99%, which meets the requirement of lactic acid polymerization. Our study represents a cost-effective and promising method for polymer-grade l-lactate production using a cheap raw bio-resource. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. A novel high color purity blue-emitting phosphor: CaBi{sub 2}B{sub 2}O{sub 7}:Tm{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jiangong, E-mail: lijiangong01@gmail.com [Department of Electronic Science and Engineering, Huanghuai University, Zhumadian 463000 (China); Yan, Huifang [Department of Foreign Languages and Literature, Huanghuai University, Zhumadian 463000 (China); Yan, Fengmei [Department of Chemistry and Chemical Engineering, Huanghuai University, Zhumadian 463000 (China)

    2016-07-15

    Graphical abstract: - Highlights: • A series of Tm{sup 3+}-doped CaBi{sub 2}B{sub 2}O{sub 7} blue-emitting phosphors were prepared. • The optimum doping content of Tm{sup 3+} ions was found. • The critical distance and concentration quenching mechanism was discussed. • The color purity of as prepared sample was analyzed and compared. - Abstract: A series of Tm{sup 3+}-doped CaBi{sub 2−x}B{sub 2}O{sub 7}:xTm{sup 3+} (0.02 ≤ x ≤ 0.12) blue-emitting phosphors with high color purity were prepared by solid-state reaction method. The crystal structure and luminescence properties of the as-prepared phosphors were studied. This phosphor shows a satisfactory blue performance (peak at 453 nm) due to the {sup 1}D{sub 2} → {sup 3}F{sub 4} transition of Tm{sup 3+} excited by 357 nm light. Investigation of Tm{sup 3+} content dependent emission spectra indicates that x = 0.04 is the optimum doping content of Tm{sup 3+} ions in the CaBi{sub 2}B{sub 2}O{sub 7} host. The critical distance and the concentration quenching mechanism were also investigated. In particular, the color purity of as prepared sample was analyzed and the result shows that the color purity of CaBi{sub 2}B{sub 2}O{sub 7}:Tm{sup 3+} is higher than the commercial blue phosphor BaMgAl{sub 10}O{sub 17}:Eu{sup 2+} (BAM:Eu{sup 2+}) and the latest reported Tm{sup 3+} doped blue phosphors. The present work suggests that the CaBi{sub 2}B{sub 2}O{sub 7}:Tm{sup 3+} phosphor is a potential blue-emitting candidate for the application in the near-UV WLEDs.

  8. High performance liquid chromatography with photo diode array for separation and analysis of naproxen and esomeprazole in presence of their chiral impurities: Enantiomeric purity determination in tablets.

    Science.gov (United States)

    Ragab, Marwa A A; El-Kimary, Eman I

    2017-05-12

    A stereoselective high performance liquid chromatographic method with diode array detection (HPLC-DAD) was introduced for S-naproxen and esomeprazole determination in tablets. The separation was achieved on a Kromasil Cellucoat chiral column using a mobile phase consisting of hexane: isopropanol: trifluoroacetic acid (TFA) (90:9.9:0.1 v/v/v). The proposed system was found to be suitable for the enantioseparation of naproxen and omeprazole biologically active isomers. After optimization of the chromatographic conditions, resolution values of 3.84 and 2.17 could be obtained for naproxen and omeprazole isomers, respectively. The method was fully validated for the determination of S-isomers of each drug in their dosage form. Also, the enentiomeric purity was determined in commercial tablet containing S-naproxen and esomeprazole. The enantiomeric purity was calculated for each drug and the chiral impurities (R-isomers) could be determined at 1% level. The method was validated and good results with respect to linearity, precision, accuracy, selectivity and robustness were obtained. The limits of detection (LOD) and quantification (LOQ) were 2.00, 6.50 and 0.10, 0.35μgmL -1 for S-naproxen and esomeprazole, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Production of R,R-2,3-butanediol of ultra-high optical purity from Paenibacillus polymyxa ZJ-9 using homologous recombination.

    Science.gov (United States)

    Zhang, Li; Cao, Can; Jiang, Ruifan; Xu, Hong; Xue, Feng; Huang, Weiwei; Ni, Hao; Gao, Jian

    2018-04-11

    The present study describes the use of metabolic engineering to achieve the production of R,R-2,3-butanediol (R,R-2,3-BD) of ultra-high optical purity (>99.99%). To this end, the diacetyl reductase (DAR) gene (dud A) of Paenibacillus polymyxa ZJ-9 was knocked out via homologous recombination between the genome and the previously constructed targeting vector pRN5101-L'C in a process based on homologous single-crossover. PCR verification confirmed the successful isolation of the dud A gene disruption mutant P. polymyxa ZJ-9-△dud A. Moreover, fermentation results indicated that the optical purity of R,R-2,3-BD increased from about 98% to over 99.99%, with a titer of 21.62 g/L in Erlenmeyer flasks. The latter was further increased to 25.88 g/L by fed-batch fermentation in a 5-L bioreactor. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. On-line purity monitoring in high-speed counter-current chromatography: application of HSCCC-HPLC-DAD for the preparation of 5-HMF, neomangiferin and mangiferin from Anemarrhena asphodeloides Bunge.

    Science.gov (United States)

    Zhou, Tingting; Zhu, Zhenyu; Wang, Chen; Fan, Guorong; Peng, Jinyong; Chai, Yifeng; Wu, Yutian

    2007-05-09

    An efficient on-line purity monitoring strategy based on on-line coupling of high-speed counter-current chromatography (HSCCC) with high-performance liquid chromatography-diode array detection (HPLC-DAD) was successfully applied for the first time to the isolation and purification of 5-hydroxymethyl-furancarboxaldehyde (5-HMF), mangiferin and neomangiferin from the Chinese medicinal plant Anemarrhena asphodeloides Bunge, a plant used in the traditional Chinese medicine. The introduction of on-line purity monitoring in HSCCC has greatly improved the efficiency of this technique by overcoming the drawbacks of post-purification sample handling in HSCCC isolation. The effluent from the outlet of HSCCC was split into two parts, and one was collected, while the other was introduced directly through a switch valve into a HPLC-DAD system for purity monitoring. Using this method the desired fractions with high purities could be collected. From 600 mg partially purified extract, 165.6 mg neomangiferin and 292.8 mg mangiferin with purities of 98.9 and 99.5%, respectively, were obtained with a two-phase solvent system composed of n-butanol-water (1:1, v/v) by increasing the flow-rate of the mobile phase stepwise from 1.0 to 2.2 ml min(-1) after 210 min. A 17.1mg 5-HMF with purity of 96.6% was also isolated for the first time.

  11. Characterization of high-purity 82Se-enriched ZnSe for double-beta decay bolometer/scintillation detectors

    Science.gov (United States)

    Silva, B. C.; de Oliveira, R.; Ribeiro, G. M.; Cury, L. A.; Leal, A. S.; Nagorny, S.; Krambrock, K.

    2018-02-01

    Zinc selenide (ZnSe), when enriched with 82Se isotope, is one of the most promising materials for the construction of a bolometer/scintillation detector to study neutrinoless double beta decay (0νDBD). Because the 0νDBD is a very rare event, a high quantity of high-purity monocrystalline ZnSe is needed, which means high costs. Therefore, the knowledge of the best material parameters, especially the presence of point defects, is essential to make feasible the construction of such a detector. In this work, both the as-grown and thermally annealed ZnSe enriched to 95% with the 82Se isotope grown by the Bridgman technique from high-purity starting materials were characterized by electron paramagnetic resonance (EPR), photo-EPR, neutron activation, photoluminescence, and electrical measurements. It is shown that although thermal annealing increases crystal homogeneity and reduces microcracks, the scintillation efficiency is much better for the as-grown material. The higher scintillation efficiency is due to the presence of donor acceptor pairs in the as-grown material, which are responsible for strong luminescence/scintillation in the red spectral region. By photo-EPR, the donor acceptor pairs are identified as closed VZn - AlZn pairs which are lost during the annealing procedure. Electrical characterization shows that the as-grown material is of good quality as it has high electron mobility at low temperatures. Excellent material parameters for the construction of the bolometer/scintillation detector based on enriched Zn82Se are discussed.

  12. An improved back-flush-to-vent gas chromatographic method for determination of trace permanent gases and carbon dioxide in ultra-high purity ammonia.

    Science.gov (United States)

    Trubyanov, Maxim M; Mochalov, Georgy M; Vorotyntsev, Ilya V; Vorotyntsev, Andrey V; Suvorov, Sergey S; Smirnov, Konstantin Y; Vorotyntsev, Vladimir M

    2016-05-20

    A novel method for rapid, quantitative determination of trace permanent gases and carbon dioxide in ultra-high purity ammonia by dual-channel two-dimensional GC-PDHID is presented. An improved matrix back-flush-to-vent approach combining back-flush column switching technique with auxiliary NaHSO4 ammonia trap is described. The NaHSO4 trap prevents traces of ammonia from entering the analytical column and is shown not to affect the impurity content of the sample. The approach allows shortening the analysis time and increasing the amount of measurements without extensive maintenance of the GC-system. The performance of the configuration has been evaluated utilizing ammonia- and helium-based calibration standards. The method has been applied for the analysis of 99.9999+% ammonia purified by high-pressure distillation at the production site. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Internal friction of very high purity lead (99,9999%) at medium temperatures; Friccion interna en plomo de muy alta pureza (99,9999%) a temperaturas medias

    Energy Technology Data Exchange (ETDEWEB)

    Gallego, I.; Gutierrez-Urrutia, I.; San Juan, J. M.; No, M. L.

    2001-07-01

    Internal friction spectra of high purity lead (99,9999%) at medium temperatures exhibit a main relaxation peak at 230 K (P{sub 1}) which depends strongly on the dislocation arrangement. The mechanisms associated to P{sub 1} relaxation has an activation area between 500b2 and 2000b 2 and its activation energy is 0.65{+-}0.05 eV 863{+-}5KJ/mol, which is only 0.6 times the auto diffusion energy of lead. The behaviour of P{sub 1} peak and its dependence on thermomechanical treatments has allowed us to conclude that it is associated to the sliding of dislocations controlled by the climbing of jogs by diffusion of vacancies along the dislocation lines. At a slightly higher temperature, another relaxation (P{sub 1}) turns up in the spectra, which can be associated to different mechanisms. (Author) 12 refs.

  14. Recovery behavior of high purity cubic SiC polycrystals by post-irradiation annealing up to 1673 K after low temperature neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Idris, Mohd Idzat, E-mail: idzat.i.aa@m.titech.ac.jp [Department of Nuclear Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550 Japan (Japan); The National University of Malaysia, School of Applied Physics, Faculty of Science and Technology, 43600 Bangi Selangor (Malaysia); Yamazaki, Saishun; Yoshida, Katsumi; Yano, Toyohiko [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550 Japan (Japan)

    2015-10-15

    Two kinds of high purity cubic (β) SiC polycrystals, PureBeta-SiC and CVD-SiC, were irradiated in the BR2 reactor (Belgium) up to a fluence of 2.0–2.5 × 10{sup 24} (E > 0.1 MeV) at 333–363 K. Changes in macroscopic lengths were examined by post-irradiation thermal annealing using a precision dilatometer up to 1673 K with a step-heating method. The specimen was held at each temperature step for 6 h and the change in length of the specimen was recorded during each isothermal annealing step from 373 K to 1673 K with 50 K increments. The recovery curves were analyzed with the first order model, and rate constants at each annealing step were obtained. Recovery of defects, induced by neutron irradiation in high purity β-SiC, has four stages of different activation energies. At 373–573 K, the activation energy of PureBeta-SiC and CVD-SiC was in the range of 0.17–0.24 eV and 0.12–0.14 eV; 0.002–0.04 eV and 0.006–0.04 eV at 723–923 K; 0.20–0.27 eV and 0.26–0.31 eV at 923–1223 K; and 1.37–1.38 eV and 1.26–1.29 eV at 1323–1523 K, respectively. Below ∼1223 K the recombination occurred possibly for closely positioned C and Si Frenkel pairs, and no long range migration is deemed essential. Nearly three-fourths of recovery, induced by neutron irradiation, occur by this mechanism. In addition, at 1323–1523 K, recombination of slightly separated C Frenkel pairs and more long-range migration of Si interstitials may have occurred for PureBeta-SiC and CVD-SiC specimens. Migration of both vacancies may be restricted up to ∼1523 K. Comparing to hexagonal α-SiC, high purity β-SiC recovered more quickly in the lower annealing temperature range of less than 873 K, in particular less than 573 K. - Highlights: • Two kinds of high purity cubic (β) SiC polycrystals were irradiated. • Macroscopic lengths were examined by post-irradiation thermal annealing. • The recovery curves were analyzed with first order model.

  15. Analysis of thermal detrapping of holes created by electron irradiation in high purity amorphous SiO{sub 2} using the induced and secondary current measurements

    Energy Technology Data Exchange (ETDEWEB)

    Said, K., E-mail: kamel.said@fss.rnu.tn [LaMaCoP, Université de Sfax, BP 1171, 3000 Sfax (Tunisia); Moya, G.; Si Ahmed, A. [Im2np, UMR 7334 CNRS, Aix-Marseille Université, 13397 Marseille Cedex 20 (France); Damamme, G. [CEA, DAM, GRAMAT, 46500 Gramat (France); Kallel, A. [LaMaCoP, Université de Sfax, BP 1171, 3000 Sfax (Tunisia)

    2016-01-15

    Graphical abstract: - Highlights: • Positive charging of high purity amorphous SiO{sub 2} achieved by electron irradiation in a specially equipped scanning electron microscope. • Quantity of detrapped holes evaluated via measurements of induced and secondary electron currents. • Study of isothermal detrapping for different temperatures (300–663 K). • Analysis of the hole detrapping via a first order kinetics. • Evaluation of the hole detrapping parameters (activation energy and frequency factor). - Abstract: Isothermal detrapping of holes after electron irradiation (using a SEM) in high purity amorphous SiO{sub 2} is evaluated at different temperatures (in the range 300–663 K) by means of the induced and secondary current measurements. In order to single out the hole detrapping, the specific charging conditions (1 keV defocused electron beam of low density) leading to positive charging are adopted. The thermal detrapping, which stems from a single trap, begins at 523 K and is completed at 663 K. After annealing in air at 973 K during 48 h, two detrapping stages are revealed: the former is connected with an additional shallow trap, while the latter requires temperatures above 663 K for a complete detrapping. The first order kinetics describes reasonably well the detrapping process. The frequency factors (near 10{sup 10} s{sup −1}) and the activation energies (about 1.6 eV) deduced from this analysis could be assigned, respectively, to the relaxation connected to detrapping and to the trap energy level of the charged oxygen vacancy.

  16. Large-scale purification of high purity α1-antitrypsin from Cohn Fraction IV with virus inactivation by solvent/detergent and dry-heat treatment.

    Science.gov (United States)

    Huangfu, Chaoji; Zhang, Jinchao; Ma, Yuyuan; Jia, Junting; Li, Jingxuan; Lv, Maomin; Ma, Xiaowei; Zhao, Xiong; Zhang, Jingang

    2017-10-26

    α1-Antitrypsin (AAT) is widely used to treat patients with congenital AAT deficiency. Cohn Fraction IV (Cohn F IV) is normally discarded during the manufacturing process of albumin but contains approximately 33% of plasma AAT. We established a new process for large-scale purification of AAT from it. liquid chromatography-electrospray ionization-tandem mass spectrometry and high-performance liquid chromatography were applied for qualitative identification and composition analysis, respectively. Stabilizers were optimized for AAT activity protection during lyophilization and dry-heat. Virus inactivation by dry-heat and solvent/detergent (S/D) was validated on a range of viruses. AAT with purity of 95.54%, specific activity of 3,938.5 IU/mg, and yield of 26.79%, was achieved. More than 95% activity was reserved after S/D. More than 96% activity was obtained after lyophilization or dry-heat. After S/D, pseudorabies virus (PRV) and vesicular stomatitis virus (VSV) were inactivated below detectable level within 1 H. Virus titer reductions of more than 5.50 log 10 and 5.38 log 10 were achieved for PRV and VSV, respectively. Porcine parvovirus and encephalomyocarditis virus were inactivated by 3.17 log 10 and 5.88 log 10 reduction after dry-heat. The advantages of this process, including suitability for large-scale production, high purity, better utilization of human plasma, viral safety, commercial and inexpensive chromatography medium, may facilitate its further application. © 2017 International Union of Biochemistry and Molecular Biology, Inc.

  17. Enhanced Crystalline Phase Purity of CH3NH3PbI3-xClx Film for High-Efficiency Hysteresis-Free Perovskite Solar Cells.

    Science.gov (United States)

    Yang, Yingguo; Feng, Shanglei; Xu, Weidong; Li, Meng; Li, Li; Zhang, Xingmin; Ji, Gengwu; Zhang, Xiaonan; Wang, Zhaokui; Xiong, Yimin; Cao, Liang; Sun, Baoquan; Gao, Xingyu

    2017-07-12

    Despite rapid successful developments toward promising perovskite solar cells (PSCs) efficiency, they often suffer significant hysteresis effects. Using synchrotron-based grazing incidence X-ray diffraction (GIXRD) with different probing depths by varying the incident angle, we found that the perovskite films consist of dual phases with a parent phase dominant in the interior and a child phase with a smaller (110) interplanar space (d (110) ) after rapid thermal annealing (RTA), which is a widely used post treatment to improve the crystallization of solution-processed perovskite films for high-performance planar PSCs. In particular, the child phase composition gradually increases with decreasing depth till it becomes the majority on the surface, which might be one of the key factors related to hysteresis in fabricated PSCs. We further improve the crystalline phase purity of the solution-processed CH 3 NH 3 PbI 3-x Cl x perovskite film (referred as g-perovskite) by using a facile gradient thermal annealing (GTA), which shows a uniformly distributed phase structure in pinhole-free morphology with less undercoordinated Pb and I ions determined by synchrotron-based GIXRD, grazing incidence small-angle X-ray scattering, scanning electron microscopy, and X-ray photoelectron spectroscopy. Regardless of device structures (conventional and inverted types), the planar heterojunction PSCs employing CH 3 NH 3 PbI 3-x Cl x g-perovskite films exhibit negligible hysteresis with a champion power conversion efficiency of 17.04% for TiO 2 -based conventional planar PSCs and 14.83% for poly(3,4-ethylenedioxythiophene:poly(styrenesulfonate) (PEDOT:PSS)-based inverted planar PSCs. Our results indicate that the crystalline phase purity in CH 3 NH 3 PbI 3-x Cl x perovskite film, especially in the surface region, plays a crucial role in determining the hysteresis effect and device performance.

  18. Application of INAA for chemical quality control analysis of C-C composite and high purity graphite by determining trace elemental concentrations

    International Nuclear Information System (INIS)

    Shinde, Amol D.; Reddy, A.V.R.; Acharya, R.; Venugopalan, Ramani

    2015-01-01

    Carbon based materials like graphite and C-C composites are used for various scientific and technological applications. Owing to its low neutron capture cross section and good moderating properties, graphite is used as a moderator or reflector in nuclear reactors. For high temperature reactors like CHTR, graphite and C-C composites are proposed as structural materials. Studies are in progress to use C-C composites as prospective candidate instead of graphite due to their excellent mechanical and thermal properties. The advantage of carbon-carbon composite is that the microstructure and the properties can be tailor made. Impurities like rare earth elements and neutron poisons which have high neutron absorption cross section and elements whose activation products of have longer half-lives like 60 Co (5.27 y), 65 Zn (244.3 d) and 59 Fe (44.5 d) are not desired in structural materials. For chemical quality control (CQC) it is necessary to evaluate accurately the impurity concentrations using a suitable non-destructive analytical technique. In the present work, two carbon/carbon composite samples and two high purity graphite samples were analyzed by Instrumental Neutron Activation Analysis (INAA) using high-flux reactor neutrons. Samples, sealed in Al foil, were irradiated in tray-rod position of Dhruva reactor, BARC at a neutron flux of ∼ 5 x 10 13 cm -2 s -1 . Radioactive assay was carried out using high resolution gamma ray spectrometry using 40% HPGe detector

  19. The Globe laid bare

    CERN Multimedia

    Anaïs Schaeffer

    2015-01-01

    If you’re at CERN at the moment, you will certainly have noticed the work under way on the Globe. The structure, which has been in pride of place opposite the Laboratory for over ten years, has never been so completely laid bare. But, as we explained in a previous article (see here), it is all for a good cause. The Globe is built entirely from wood and certain parts of it need to be replaced.   The Globe after the removal of all the sun baffles. Image: Lucien Fortunati. Picture the general structure of the Globe. In simple terms, the building consists of two spheres, one inside the other. The inner sphere houses the Universe of Particles exhibition and the conference room and is connected to the outer sphere by two access ramps. “Each of these two spheres is made up of eighteen large supporting arcs,” explains Amaya Martínez García of the GS department, who is supervising the Globe renovation project. “These eighteen arcs are ...

  20. Trace amounts of rare earth elements in high purity samarium oxide by sector field inductively coupled plasma mass spectrometry after separation by HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Pedreira, W.R. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil) and Fundacao Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho (FUNDACENTRO), 05409-002 Sao Paulo, SP (Brazil)]. E-mail: walter.pedreira@fundacentro.gov.br; Queiroz, C.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Abrao, A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Rocha, S.M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Vasconcellos, M.E. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Boaventura, G.R. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil); Pimentel, M.M. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil)

    2006-07-20

    Today there is an increasing need for high purity rare earth compounds in various fields, the optical, the electronics, the ceramic, the nuclear and geochemistry. Samarium oxide has special uses in glass, phosphors, lasers and thermoelectric devices. Calcium chloride crystals treated with samarium have been employed in lasers, which produce light beams intense enough to burn metal. In general, the inductively coupled plasma mass spectrometry (ICP-MS) presents some advantages for trace element analysis, due to high sensitivity and resolution, when compared with other analytical techniques such as ICP optical emission spectrometry (ICP-OES). In this work, sector field inductively coupled plasma mass spectrometry was used. Sixteen elements (Sc, Y and 14 lanthanides) were determined selectively with the ICP-MS system using a concentration gradient method. The detection limits with the ICP-MS system were about 0.2 (La) pg mL{sup -1} to 8 (Gd) pg mL{sup -1}. The %R.S.D. of the methods varying between 0.9 and 1.5% for a set of five (n = 5) replicates was found for the IPEN's material and for the certificate reference sample. Determination of trace REEs in two high pure samarium oxides samples (IPEN and JMC) was performed. IPEN's material is highly pure (>99.99%) and was successfully analyzed without spectral interference (MO{sup +} and MOH{sup +})

  1. Major Role of NAD-Dependent Lactate Dehydrogenases in the Production of l-Lactic Acid with High Optical Purity by the Thermophile Bacillus coagulans.

    Science.gov (United States)

    Wang, Limin; Cai, Yumeng; Zhu, Lingfeng; Guo, Honglian; Yu, Bo

    2014-12-01

    Bacillus coagulans 2-6 is an excellent producer of optically pure l-lactic acid. However, little is known about the mechanism of synthesis of the highly optically pure l-lactic acid produced by this strain. Three enzymes responsible for lactic acid production-NAD-dependent l-lactate dehydrogenase (l-nLDH; encoded by ldhL), NAD-dependent d-lactate dehydrogenase (d-nLDH; encoded by ldhD), and glycolate oxidase (GOX)-were systematically investigated in order to study the relationship between these enzymes and the optical purity of lactic acid. Lactobacillus delbrueckii subsp. bulgaricus DSM 20081 (a d-lactic acid producer) and Lactobacillus plantarum subsp. plantarum DSM 20174 (a dl-lactic acid producer) were also examined in this study as comparative strains, in addition to B. coagulans. The specific activities of key enzymes for lactic acid production in the three strains were characterized in vivo and in vitro, and the levels of transcription of the ldhL, ldhD, and GOX genes during fermentation were also analyzed. The catalytic activities of l-nLDH and d-nLDH were different in l-, d-, and dl-lactic acid producers. Only l-nLDH activity was detected in B. coagulans 2-6 under native conditions, and the level of transcription of ldhL in B. coagulans 2-6 was much higher than that of ldhD or the GOX gene at all growth phases. However, for the two Lactobacillus strains used in this study, ldhD transcription levels were higher than those of ldhL. The high catalytic efficiency of l-nLDH toward pyruvate and the high transcription ratios of ldhL to ldhD and ldhL to the GOX gene provide the key explanations for the high optical purity of l-lactic acid produced by B. coagulans 2-6. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  2. Millimeter wave complex refractive index, complex dielectric permittivity and loss tangent of extra high purity and compensated silicon

    Energy Technology Data Exchange (ETDEWEB)

    Afsar, M.N.; Chi, H. [Tufts Univ., Medford, MA (United States)

    1994-07-01

    Single crystal high resistivity (11,000 ohm-cm) boron doped silicon was found to exhibit lowest absorption loss at room temperature (25 C) in the entire millimeter wave region. At 140 GHz it`s loss tangent value is as low as 40 microradians. The study of dielectric properties of silicon as a function of resistivity reveals that the low frequency free carrier absorption present in all silicon (and other semiconductors) vanishes with increasing resistivity. It is then possible to use such a silicon in substrate applications in microwave integrated circuitry. The unique broadband dispersive Fourier transform spectroscopic technique was utilized for these measurement.

  3. Synthesis of high-purity precipitated calcium carbonate during the process of recovery of elemental sulphur from gypsum waste.

    Science.gov (United States)

    de Beer, M; Doucet, F J; Maree, J P; Liebenberg, L

    2015-12-01

    We recently showed that the production of elemental sulphur and calcium carbonate (CaCO3) from gypsum waste by thermally reducing the waste into calcium sulphide (CaS) followed by its direct aqueous carbonation yielded low-grade carbonate products (i.e. production of high-grade CaCO3 (i.e. >99 mass% as CaCO3) or precipitated calcium carbonate (PCC). The process used an acid gas (H2S) to improve the aqueous dissolution of CaS, which is otherwise poorly soluble. The carbonate product was primarily calcite (99.5%) with traces of quartz (0.5%). Calcite was the only CaCO3 polymorph obtained; no vaterite or aragonite was detected. The product was made up of micron-size particles, which were further characterised by XRD, TGA, SEM, BET and true density. Results showed that about 0.37 ton of high-grade PCC can be produced from 1.0 ton of gypsum waste, and generates about 0.19 ton of residue, a reduction of 80% from original waste gypsum mass to mass of residue that needs to be discarded off. The use of gypsum waste as primary material in replacement of mined limestone for the production of PPC could alleviate waste disposal problems, along with converting significant volumes of waste materials into marketable commodities. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Trace Element Compositions and Defect Structures of High-Purity Quartz from the Southern Ural Region, Russia

    Directory of Open Access Journals (Sweden)

    Jens Götze

    2017-10-01

    Full Text Available Quartz samples of different origin from 10 localities in the Southern Ural region, Russia have been investigated to characterize their trace element compositions and defect structures. The analytical combination of cathodoluminescence (CL microscopy and spectroscopy, electron paramagnetic resonance (EPR spectroscopy, and trace-element analysis by inductively coupled plasma mass spectrometry (ICP-MS revealed that almost all investigated quartz samples showed very low concentrations of trace elements (cumulative concentrations of <50 ppm with <30 ppm Al and <10 ppm Ti and low abundances of paramagnetic defects, defining them economically as “high-purity” quartz (HPQ suitable for high-tech applications. EPR and CL data confirmed the low abundances of substitutional Ti and Fe, and showed Al to be the only significant trace element structurally bound in the investigated quartz samples. CL microscopy revealed a heterogeneous distribution of luminescence centres (i.e., luminescence active trace elements such as Al as well as features of deformation and recrystallization. It is suggested that healing of defects due to deformation-related recrystallization and reorganization processes of the quartz lattice during retrograde metamorphism resulted in low concentrations of CL activator and other trace elements or vacancies, and thus are the main driving processes for the formation of HPQ deposits in the investigated area.

  5. High-purity preparation of HSV-2 vaccine candidate ACAM529 is immunogenic and efficacious in vivo.

    Directory of Open Access Journals (Sweden)

    Sophia T Mundle

    Full Text Available Genital herpes is a sexually transmitted infection (STI caused by herpes simplex virus 2 (HSV-2 and to a lesser extent herpes simplex virus 1 (HSV-1. Infection by HSV-2 is life-long and is associated with significant cost to healthcare systems and social stigma despite the highly prevalent nature of the disease. For instance, the proportion of HSV-2 seropositive to seronegative adults is approximately 1 in 5 in the US and greater than 4 in 5 in some areas of sub-Saharan Africa. The replication-defective vaccine strain virus dl5-29 was re-derived using cells appropriate for GMP manufacturing and renamed ACAM529. Immunization with dl5-29 was previously reported to be protective both in mice and in guinea pigs, however these studies were performed with vaccine that was purified using methods that cannot be scaled for manufacturing of clinical material. Here we describe methods which serve as a major step towards preparation of ACAM529 which may be suitable for testing in humans. ACAM529 can be harvested from infected cell culture of the trans-complementing cell line AV529 clone 19 (AV529-19 without mechanical cell disruption. ACAM529 may then be purified with respect to host cell DNA and proteins by a novel purification scheme, which includes a combination of endonuclease treatment, depth filtration, anion-exchange chromatography and ultrafiltration/diafiltration (UF/DF. The resultant virus retains infectivity and is ∼ 200-fold more pure with respect to host cell DNA and proteins than is ACAM529 purified by ultracentrifugation. Additionally, we describe a side-by-side comparison of chromatography-purified ACAM529 with sucrose cushion-purified ACAM529, which shows that both preparations are equally immunogenic and protective when tested in vivo.

  6. A solid-sampling system for a transversely heated graphite furnace and its application to trace element analysis of high-purity tantalum powders by atomic absorption spectrometry

    Science.gov (United States)

    Friese, Klaus-Christian; Krivan, Viliam

    1998-08-01

    An electrothermal atomic absorption spectrometer with transversely heated graphite tube and a solid-sampling system was applied to the direct analysis of high-purity tantalum powders. Sample introduction was based on the `boat' technique. The optimized sample platform was short enough to fit completely into the tube and its semicylindrical cross-section allowed the introduction of sample volumes up to 30 μl. The platform manipulator constructed for the handling of these boats provided high mechanical precision, low risk of contamination and rapid operation. The maximum applicable tantalum sample amount was 60 mg per atomization. For the analyte elements Cu, Fe, K, Mg, Mn, Na and Zn, the method provided limits of detection of 0.15, 4.0, 0.1, 1.3, 0.12, 0.16 and 0.02 ng g -1, respectively. Calibration was performed using aqueous standard solutions, and the results agreed satisfactorily with those obtained by ETAAS involving sample digestion.

  7. Catalyst evaluation for high-purity H2 production by sorption-enhanced steam-methane reforming coupled to a Ca/Cu process

    Science.gov (United States)

    Navarro, M. V.; López, J. M.; García, T.; Grasa, G.; Murillo, R.

    2017-09-01

    The operational limits of a commercial nickel-based catalyst under the conditions of a sorption-enhanced steam-methane reforming process coupled to a Ca/Cu chemical loop are investigated for high-purity H2 production in a cyclic operation. The performance of the reforming catalyst is tested by means of a high number of oxidation-reduction-reforming cycles. After 100 oxidation-reduction cycles, this catalyst retains its exceptional reforming activity. The methane conversion values are close to the thermodynamic equilibrium under very demanding conditions: temperature between 500 °C - 700 °C and mass hourly space velocity of 8.8 kgCH4 h-1 kgcat-1. After 200 cycles, the sample shows reduction in its reforming activity in line with a lower dispersion of the Ni species. Sintering of Ni nanocrystals is evidenced during the oxidation-reduction multi-cycles. The performance of the catalyst after 200 oxidation-reduction cycles mixed with a CaO-based CO2 sorbent is studied under optimal conditions calculated for the sorption-enhanced reforming process coupled to a Ca/Cu cycle (temperature of 650 °C, steam/methane ratio of 4, sorbent/catalyst ratio of 4 and space velocity of 0.75 kgCH4 h-1 kgcat-1). Remarkably, an equilibrium value over 92 vol.% H2 concentration is achieved, highlighting this catalyst as a promising candidate for the next steps of the process development.

  8. Technology development for recovery of individual rare earth elements at high purity from Dong-Pao rare earth concentrated ore of Vietnam

    International Nuclear Information System (INIS)

    Hoang Nhuan; Le Ba Thuan; Luu Xuan Dinh; Tran Hoang Mai; Tran Thi Hong Thai; Yoshiuyki Aiba; Hiroaki Nishimura

    2015-01-01

    In this work, the research results on RE processing process at laboratory scale and pilot scale was reported and discussed. Experimental research on thermal decomposition and sulfate process of bastnaesite ore with sulfuric acid in electric furnace was carried out, the different roasting conditions, mass transfer rate, reactions and RE and/or non-RE behaviors during roasting and leaching were investigated. The roasting temperatures were 450 o C and 550 o C. With higher roasting temperature and longer roasting time, the RE recovery yield reduced. The RE recovery yield reached the highest (over 94%) at roasting temperature of 550 o C for 2 hrs. The different extracting conditions for separation of REEs were investigated in laboratory scale as well as pilot scale. At pilot scale, the separation of REEs was performed on 120-stage extraction system produced by Japan, using PC88A solvent dissolved in IP2028. The volume of each stage was 20 L. The results showed that REEs were separated from RE resource of Vietnam and individual RE elements such as La, Ce, Pr, and Nd were obtained at high purity. The parameters for each extraction stage were reported in this work. The results indicated that in order to obtain highly purified Nd (>99%), it needs to use an extraction system with higher stage number, about 200 stages. The extraction data at pilot scale of this investigation was used as basic data for calculating parameters for extraction system in industrial scale. (author)

  9. Incidence of factor IX inhibitor development in severe haemophilia B patients treated with only one brand of high purity plasma derived factor IX concentrate.

    Science.gov (United States)

    Parquet, A; Laurian, Y; Rothschild, C; Navarro, R; Guérois, C; Gay, V; Durin, A; Peynet, J; Sultan, Y

    1999-10-01

    Fifteen previously untreated patients (Pups) with severe haemophilia B (factor IX activity brand of plasma-derived high purity factor IX concentrate (FIX LFB) were studied. Age at first injection varied from 1 to 137 months and follow-up since this first injection from 21 to 86 months (median: 35). Cumulative exposure days (CED) were from 4 to over 100 (median: 26). Among these 15 Pups only one developed an inhibitor. Mutation analysis performed in all patients showed total gene deletion in the patient with inhibitor, partial gene deletion in another one, and missense mutations in 9 families. Mutation was not found in one patient. Actually, according to the data already published, only two patients were at high risk for inhibitor development in our population. Our study, although rather small, confirms the previously reported low incidence of inhibitors in haemophilia B. Large studies on incidence of FIX inhibitors are indeed difficult to perform, due to both the overall small number of severe haemophilia B patients and the low incidence of FIX inhibitors. Consequently, the impact of bias, such as prevalence of different types of gene defects in a given population, is major. Therefore, any study, dealing with incidence of FIX inhibitors in severe haemophilia B should report, for each patient, the type of gene defect.

  10. Use of alkali metal salts to prepare high purity single-walled carbon nanotube solutions and thin films

    Science.gov (United States)

    Ashour, Rakan F.

    Single-walled carbon nanotubes (SWCNTs) display interesting electronic and optical properties desired for many advanced thin film applications, such as transparent conductive electrodes or thin-film transistors. Large-scale production of SWCNTs generally results in polydispersed mixtures of nanotube structures. Since SWCNT electronic character (conducting or semiconducting nature) depends on the nanotube structure, application performance is being held back by this inability to discretely control SWCNT synthesis. Although a number of post-production techniques are able to separate SWCNTs based on electronic character, diameter, or chirality, most still suffer from the disadvantage of high costs of materials, equipment, or labor intensity to be relevant for large-scale production. On the other hand, chromatographic separation has emerged as a method that is compatible with large scale separation of metallic and semiconducting SWCNTs. In this work, SWCNTs, in an aqueous surfactant suspension of sodium dodecyl sulfate (SDS), are separated by their electronic character using a gel chromatography process. Metallic SWCNTs (m-SWCNTs) are collected as initial fractions since they show minimum interaction with the gel medium, whereas, semiconducting SWCNTs (sc- SWCNTs) remain adsorbed to the gel. The process of sc-SWCNT retention in the gel is found to be driven by the packing density of SDS around the SWCNTs. Through a series of separation experiments, it is shown that sc-SWCNTs can be eluted from the gel simply by disturbing the configuration of the SDS/SWCNT micellar structure. This is achieved by either introducing a solution containing a co-surfactant, such as sodium cholate (SC), or solutions of alkali metal ionic salts. Analysis of SWCNT suspensions by optical absorption provides insights into the effect of changing the metal ion (M+ = Li+, Na+, and K+) in the eluting solution. Salts with smaller metal ions (e.g. Li+) require higher concentrations to achieve

  11. Preparation and quality assessment of high-purity ginseng total saponins by ion exchange resin combined with macroporous adsorption resin separation.

    Science.gov (United States)

    Zhao, Yu-Nan; Wang, Zhong-Li; Dai, Jian-Guo; Chen, Lin; Huang, Yu-Fang

    2014-05-01

    To prepare high-purity ginseng total saponins from a water decoction of Chinese ginseng root. Total saponins were efficiently purified by dynamic anion-cation exchange following the removal of hydrophilic impurities by macroporous resin D101. For quality control, ultrahigh-performance liquid chromatography with a charged aerosol detector (CAD) was applied to quantify marker components. The total saponin content was estimated by a colorimetric method using a vanillin-vitriol system and CAD response. D201, which consisted of a cross-linked polystyrene matrix and -N(+)(CH3)3 functional groups, was the best of the four anion exchange resins tested. However, no significant difference in cation exchange ability was observed between D001 (strong acid) and D113 (weak acid), although they have different functional groups and matrices. After purification in combination with D101, D201, and D113, the estimated contents of total saponins were 107% and 90% according to the colorimetric method and CAD response, respectively. The total amount of representative ginsenosides Re, Rd, Rg1, and compound K was approximately 22% based on ultrahigh-performance liquid chromatography-CAD quantitative analysis. These findings suggest that an ion exchange resin, combined with macroporous adsorption resin separation, is a promising and feasible purification procedure for neutral natural polar components. Copyright © 2014 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

  12. Genotypic and phenotypic diversity of Ralstonia pickettii and Ralstonia insidiosa isolates from clinical and environmental sources including High-purity Water.

    LENUS (Irish Health Repository)

    Ryan, Michael P

    2011-08-30

    Abstract Background Ralstonia pickettii is a nosocomial infectious agent and a significant industrial contaminant. It has been found in many different environments including clinical situations, soil and industrial High Purity Water. This study compares the phenotypic and genotypic diversity of a selection of strains of Ralstonia collected from a variety of sources. Results Ralstonia isolates (fifty-nine) from clinical, industrial and environmental origins were compared genotypically using i) Species-specific-PCR, ii) PCR and sequencing of the 16S-23S rRNA Interspatial region (ISR) iii) the fliC gene genes, iv) RAPD and BOX-PCR and v) phenotypically using biochemical testing. The species specific-PCR identified fifteen out of fifty-nine designated R. pickettii isolates as actually being the closely related species R. insidiosa. PCR-ribotyping of the 16S-23S rRNA ISR indicated few major differences between the isolates. Analysis of all isolates demonstrated different banding patterns for both the RAPD and BOX primers however these were found not to vary significantly. Conclusions R. pickettii species isolated from wide geographic and environmental sources appear to be reasonably homogenous based on genotypic and phenotypic characteristics. R. insidiosa can at present only be distinguished from R. pickettii using species specific PCR. R. pickettii and R. insidiosa isolates do not differ significantly phenotypically or genotypically based on environmental or geographical origin.

  13. Open fermentative production of L-lactic acid with high optical purity by thermophilic Bacillus coagulans using excess sludge as nutrient.

    Science.gov (United States)

    Ma, Kedong; Maeda, Toshinari; You, Huiyan; Shirai, Yoshihito

    2014-01-01

    The development of a low-cost polymer-grade L-lactic acid production process was achieved in this study. Excess sludge hydrolyzate (ESH) was chosen as nutrient source for the objective of reducing nutrient cost in lactic acid production. 1% of ESH had high performance in lactic acid production relative to 2g/l yeast extract (YE) while the production cost of ESH was much lower than that of YE, indicating ESH was a promising substitute of YE. By employing a thermophilic strain of Bacillus coagulans (NBRC 12583), non-sterilized batch and repeated batch L-lactic acid fermentation was successfully performed, and the optical purity of L-lactic acid accumulated was more than 99%. Moreover, the factors associated with cell growth and lactic acid fermentation was investigated through a two-stage lactic acid production strategy. Oxygen played an important role in cell growth, and the optimal condition for cell growth and fermentation was pH 7.0 and 50°C. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. A method for high purity intestinal epithelial cell culture from adult human and murine tissues for the investigation of innate immune function.

    Science.gov (United States)

    Graves, Christina L; Harden, Scott W; LaPato, Melissa; Nelson, Michael; Amador, Byron; Sorenson, Heather; Frazier, Charles J; Wallet, Shannon M

    2014-12-01

    Intestinal epithelial cells (IECs) serve as an important physiologic barrier between environmental antigens and the host intestinal immune system. Thus, IECs serve as a first line of defense and may act as sentinel cells during inflammatory insults. Despite recent renewed interest in IEC contributions to host immune function, the study of primary IEC has been hindered by lack of a robust culture technique, particularly for small intestinal and adult tissues. Here, a novel adaptation for culture of primary IEC is described for human duodenal organ donor tissue as well as duodenum and colon of adult mice. These epithelial cell cultures display characteristic phenotypes and are of high purity. In addition, the innate immune function of human primary IEC, specifically with regard to Toll-like receptor (TLR) expression and microbial ligand responsiveness, is contrasted with a commonly used intestinal epithelial cell line (HT-29). Specifically, TLR expression at the mRNA level and production of cytokine (IFNγ and TNFα) in response to TLR agonist stimulation is assessed. Differential expression of TLRs as well as innate immune responses to ligand stimulation is observed in human-derived cultures compared to that of HT-29. Thus, use of this adapted method to culture primary epithelial cells from adult human donors and from adult mice will allow for more appropriate studies of IECs as innate immune effectors. Published by Elsevier B.V.

  15. 1-GWh diurnal load-leveling superconducting magnetic energy storage system reference design. Appendix B: cost study, high-purity aluminum production

    International Nuclear Information System (INIS)

    Cochran, C.N.; Dawless, R.K.; Whitchurch, J.B.

    1979-09-01

    Cost information is supplied for aluminum with purities of 200, 2000, and 5000 residual resistivity ratio. Two production situations were used for each purity: (1) 1 x 10 6 kg/yr production rate with a 30-yr sustaining market and (2) 1 x 10 6 kg/yr production rate for 2 yrs only. These productions and purities are of interest for manufacturing devices for Superconducting Magnetic Energy Storage. The cost study results are presented as a range and include (1) the selling price of the aluminum for each case, (2) the cost of facilities including construction, engineering, and related costs, (3) the cost of money and depreciation (interest/amortization), and (4) the energy costs - the total of power and fuel. The range is affected by possible production variations and other uncertainties. Information is also given on plant location options and the preferred feed to the purification facility

  16. A radio-high-performance liquid chromatography dual-flow cell gamma-detection system for on-line radiochemical purity and labeling efficiency determination

    DEFF Research Database (Denmark)

    Lindegren, S; Jensen, H; Jacobsson, L

    2014-01-01

    In this study, a method of determining radiochemical yield and radiochemical purity using radio-HPLC detection employing a dual-flow-cell system is evaluated. The dual-flow cell, consisting of a reference cell and an analytical cell, was constructed from two PEEK capillary coils to fit into the w......In this study, a method of determining radiochemical yield and radiochemical purity using radio-HPLC detection employing a dual-flow-cell system is evaluated. The dual-flow cell, consisting of a reference cell and an analytical cell, was constructed from two PEEK capillary coils to fit...

  17. Improved target system for production of high purity [18F]fluorine via the 18O(p,n)18F reaction.

    Science.gov (United States)

    Hess, E; Blessing, G; Coenen, H H; Qaim, S M

    2000-06-01

    An improved aluminium target system for production of elemental fluorine via the 18O(p,n)18F reaction using a two-step irradiation protocol is described. In the first step highly enriched gaseous oxygen-18 is irradiated with protons to form fluorine-18 which gets deposited on the inner target surface. In the second step, after cryogenic recovery of oxygen-18 target gas, a mixture of elemental 'cold' fluorine and krypton is introduced and a short proton irradiation is done, whereby an isotopic exchange between the gaseous fluorine and the deposited radiofluorine occurs. The second step leads to the recovery of the radiofluorine as [18F]fluorine. Optimisation studies were performed regarding the yield and specific radioactivity of [18F]fluorine. Furthermore, some irradiation parameters relevant to the recovery step were investigated. It was found that a 15 to 20 min irradiation with a beam current of 20 microA is sufficient for the isotopic exchange between the fluorine-carrier and the 18F-radioactivity deposited on the inner wall of the target. The distribution of the 18F-radioactivity deposited on the inner target surface is inhomogeneous, probably due to convection effects. Extensive radioanalytical techniques were applied to characterise the reactivity of [18F]fluorine and to identify undesired nonreactive 18F-compounds, mainly [18F]tetrafluoromethane and [18F]nitrogentrifluoride. The [18F]fluorine produced in the system used has the distinction of having a negligible contamination from those inert 18F-compounds. This is a combined effect of the use of highest purity gases and a welded target construction, which avoids any contact of the gases with organic material during irradiations. The target has proved to be very reliable for production of [18F]fluorine in high yields of up to 34 GBq and specific activities of 350-600 GBq/mmol, both at 30 min after end of activation bombardment.

  18. Peculiarities of high-amplitude dislocation internal friction in molybdenum single crystals of high purity in the temperature range 5.9 to 300 K

    International Nuclear Information System (INIS)

    Kaufmann, H.J.; Pal-Val, P.P.

    1982-01-01

    Amplitude dependences of internal friction in molybdenum single crystals of the orientations , , , are studied. The residual resistance ratio of the samples is (1 to 2) x 10 5 . The measurements are carried out at the frequency of 88 kHz in the temperature range 5.9 to 300 K. At low temperatures (<= 90 K) a maximum is found in the decrement amplitude dependences the height of which decreases rapidly with decreasing temperature. In this case the maximum position in the amplitude deformation axis does not change. In the same amplitude range a saturation region appears in the modulus defect amplitude dependences the magnitude of which also decreases rapidly with decreasing temperature. The observed behaviour of amplitude-dependent internal friction testifies to the fact that while decreasing temperature the losses connected with dislocation unpinning from the pinning centres decrease sharply. In molybdenum single crystals of lower purity or deformed at room temperature a maximum in the decrement amplitude dependences measured in the same amplitude range is absent. The peculiarities described cannot be explained in the framework of the theories presented. (author)

  19. Effect of collective response on the X-ray emission due to electron capture in high energy bare ion collisions with fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Kadhane, Umesh; Singh, Y.P.; Misra, D.; Tribedi, Lokesh C. E-mail: lokesh@tifr.res.in

    2003-05-01

    Electron capture by bare S ions was studied in collision with C{sub 60} and gas targets. The Lyman X-rays from the projectile were detected. It is observed that the intensity ratios of different Lyman X-ray lines in collisions with C{sub 60} are substantially lower than that for the gas targets. An attempt is made to explain this observation as a 'solid-like' effect, namely, wake field induced stark mixing of the excited states populated via electron capture.

  20. Improved target system for production of high purity [{sup 18}F]fluorine via the {sup 18}O(p,n){sup 18}F reaction

    Energy Technology Data Exchange (ETDEWEB)

    Hess, E.; Blessing, G.; Coenen, H.H.; Qaim, S.M. E-mail: s.m.qaim@fz-juelich.de

    2000-06-01

    An improved aluminium target system for production of elemental fluorine via the {sup 18}O(p,n){sup 18}F reaction using a two-step irradiation protocol is described. In the first step highly enriched gaseous oxygen-18 is irradiated with protons to form fluorine-18 which gets deposited on the inner target surface. In the second step, after cryogenic recovery of oxygen-18 target gas, a mixture of elemental 'cold' fluorine and krypton is introduced and a short proton irradiation is done, whereby an isotopic exchange between the gaseous fluorine and the deposited radiofluorine occurs. The second step leads to the recovery of the radiofluorine as [{sup 18}F]fluorine. Optimisation studies were performed regarding the yield and specific radioactivity of [{sup 18}F]fluorine. Furthermore, some irradiation parameters relevant to the recovery step were investigated. It was found that a 15 to 20 min irradiation with a beam current of 20 {mu}A is sufficient for the isotopic exchange between the fluorine-carrier and the {sup 18}F-radioactivity deposited on the inner wall of the target. The distribution of the {sup 18}F-radioactivity deposited on the inner target surface is inhomogeneous, probably due to convection effects. Extensive radioanalytical techniques were applied to characterise the reactivity of [{sup 18}F]fluorine and to identify undesired nonreactive {sup 18}F-compounds, mainly [{sup 18}F]tetrafluoromethane and [{sup 18}F]nitrogentrifluoride. The [{sup 18}F]fluorine produced in the system used has the distinction of having a negligible contamination from those inert {sup 18}F-compounds. This is a combined effect of the use of highest purity gases and a welded target construction, which avoids any contact of the gases with organic material during irradiations. The target has proved to be very reliable for production of [{sup 18}F]fluorine in high yields of up to 34 GBq and specific activities of 350-600 GBq/mmol, both at 30 min after end of activation

  1. Couples Magnetic and Structural Transitions in High-Purity Dy and Gd5SbxGe4-x

    Energy Technology Data Exchange (ETDEWEB)

    Chernyshov, Alexander S. [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    Magnetic materials exhibiting magnetic phase transitions simultaneously with structural rearrangements of their crystal lattices hold a promise for numerous applications including magnetic refrigeration, magnetomechanical devices and sensors. We undertook a detailed study of a single crystal of dysprosium metal, which is a classical example of a system where magnetic and crystallographic sublattices can be either coupled or decoupled from one another. Magnetocaloric effect, magnetization, ac magnetic susceptibility, and heat capacity of high purity single crystals of dysprosium have been investigated over broad temperature and magnetic field intervals with the magnetic field vector parallel to either the a- or c-axes of the crystal. Notable differences in the behavior of the physical properties when compared to Dy samples studied in the past have been observed between 110 K and 125 K, and between 178 K and ~210 K. A plausible mechanism based on the formation of antiferromagnetic clusters in the impure Dy has been suggested in order to explain the reduction of the magnetocaloric effect in the vicinity of the Neel point. Experimental and theoretical investigations of the influence of commensurability effects on the magnetic phase diagram and the value of the magnetocaloric effect have been conducted. The presence of newly found anomalies in the physical properties has been considered as evidence of previously unreported states of Dy. The refined magnetic phase diagram of dysprosium with the magnetic field vector parallel to the a-axis of a crystal has been constructed and discussed. The magnetic and crystallographic properties of Gd5SbxGe4-x pseudo-binary system were studied by x-ray diffraction (at room temperature), heat capacity, ac-magnetic susceptibility, and magnetization in the temperature interval 5-320 K in magnetic fields up to 100 kOe. The magnetic properties of three composition (x = 0.5, 1,2) were examined in detail. The

  2. Creating high-resolution bare-earth digital elevation models (DEMs) from stereo imagery in an area of densely vegetated deciduous forest using combinations of procedures designed for lidar point cloud filtering

    Science.gov (United States)

    DeWitt, Jessica D.; Warner, Timothy A.; Chirico, Peter G.; Bergstresser, Sarah E.

    2017-01-01

    For areas of the world that do not have access to lidar, fine-scale digital elevation models (DEMs) can be photogrammetrically created using globally available high-spatial resolution stereo satellite imagery. The resultant DEM is best termed a digital surface model (DSM) because it includes heights of surface features. In densely vegetated conditions, this inclusion can limit its usefulness in applications requiring a bare-earth DEM. This study explores the use of techniques designed for filtering lidar point clouds to mitigate the elevation artifacts caused by above ground features, within the context of a case study of Prince William Forest Park, Virginia, USA. The influences of land cover and leaf-on vs. leaf-off conditions are investigated, and the accuracy of the raw photogrammetric DSM extracted from leaf-on imagery was between that of a lidar bare-earth DEM and the Shuttle Radar Topography Mission DEM. Although the filtered leaf-on photogrammetric DEM retains some artifacts of the vegetation canopy and may not be useful for some applications, filtering procedures significantly improved the accuracy of the modeled terrain. The accuracy of the DSM extracted in leaf-off conditions was comparable in most areas to the lidar bare-earth DEM and filtering procedures resulted in accuracy comparable of that to the lidar DEM.

  3. Self-assembled SnO2 micro- and nanosphere-based gas sensor thick films from an alkoxide-derived high purity aqueous colloid precursor

    Science.gov (United States)

    Kelp, G.; Tätte, T.; Pikker, S.; Mändar, H.; Rozhin, A. G.; Rauwel, P.; Vanetsev, A. S.; Gerst, A.; Merisalu, M.; Mäeorg, U.; Natali, M.; Persson, I.; Kessler, V. G.

    2016-03-01

    Tin oxide is considered to be one of the most promising semiconductor oxide materials for use as a gas sensor. However, a simple route for the controllable build-up of nanostructured, sufficiently pure and hierarchical SnO2 structures for gas sensor applications is still a challenge. In the current work, an aqueous SnO2 nanoparticulate precursor sol, which is free of organic contaminants and sorbed ions and is fully stable over time, was prepared in a highly reproducible manner from an alkoxide Sn(OR)4 just by mixing it with a large excess of pure neutral water. The precursor is formed as a separate liquid phase. The structure and purity of the precursor is revealed using XRD, SAXS, EXAFS, HRTEM imaging, FTIR, and XRF analysis. An unconventional approach for the estimation of the particle size based on the quantification of the Sn-Sn contacts in the structure was developed using EXAFS spectroscopy and verified using HRTEM. To construct sensors with a hierarchical 3D structure, we employed an unusual emulsification technique not involving any additives or surfactants, using simply the extraction of the liquid phase, water, with the help of dry butanol under ambient conditions. The originally generated crystalline but yet highly reactive nanoparticles form relatively uniform spheres through self-assembly and solidify instantly. The spheres floating in butanol were left to deposit on the surface of quartz plates bearing sputtered gold electrodes, producing ready-for-use gas sensors in the form of ca. 50 μm thick sphere-based-films. The films were dried for 24 h and calcined at 300 °C in air before use. The gas sensitivity of the structures was tested in the temperature range of 150-400 °C. The materials showed a very quickly emerging and reversible (20-30 times) increase in electrical conductivity as a response to exposure to air containing 100 ppm of H2 or CO and short (10 s) recovery times when the gas flow was stopped.Tin oxide is considered to be one of the

  4. Bare coordination: the semantic shift

    NARCIS (Netherlands)

    de Swart, Henriette|info:eu-repo/dai/nl/074764187; Le Bruyn, Bert|info:eu-repo/dai/nl/30484912X

    2014-01-01

    This paper develops an analysis of the syntax-semantics interface of two types of split coordination structures. In the first type, two bare singular count nouns appear as arguments in a coordinated structure, as in bride and groom were happy. We call this the N&N construction. In the second type,

  5. Analysis of the Purity of Cetrimide by Titrations

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Rasmussen, Claus/Dallerup; Nielsen, Hans/Boye

    2006-01-01

    The purity of cetrimide, trimethyl tetradecyl ammonium bromide (TTAB), that is an important preservative of many cosmetic and pharmaceutical products, was determined by three independent methods of titration. Traditionally, cetrimide was analysed by an assay method of the European Pharmacopoeia (Ph....... Eur.), which showed consistently a low purity of cetrimide with large standard deviations associated, however. A systematic 3% bias of the Ph. Eur. assay method was identified by comparing the result with results of two alternative methods of titration that exhibited high precision and high accuracy....... Titration by perchloric acid showed a 99.69 ± 0.05 % purity of cetrimide and titration by silver nitrate showed a 99.85% ± 0.05 % purity while the traditional assay method predicted a purity of only 97.1 ± 0.4. It was found that the discrepancy could be identified as differences in selectivity during...

  6. Role of water in the tribochemical removal of bare silicon

    International Nuclear Information System (INIS)

    Chen, Cheng; Xiao, Chen; Wang, Xiaodong; Zhang, Peng; Chen, Lei; Qi, Yaqiong; Qian, Linmao

    2016-01-01

    Highlights: • The wear of bare silicon against SiO 2 micro-spherical tip is a tribochemical process with participation of water. • The water amount at Si/SiO 2 interface plays a significant role on the wear of bare silicon. • The role of water relies on the hydroxylation by auto-ionized OH − , the hydrolysis of H 2 O molecules, and the dissolution of SiO m H n in water. - Abstract: Nanowear tests of bare silicon against a SiO 2 microsphere were conducted in air (relative humidity [RH] = 0%–89%) and water using an atomic force microscope. Experimental results revealed that the water played an important role in the tribochemical wear of the bare silicon. A hillock-like wear trace with a height of 0.7 nm was generated on the bare silicon surface in dry air. As the RH increased, the wear depth increased and reached the maximum level in water. Analysis of frictional dissipated energy suggested that the wear of the bare silicon was not dominated by mechanical interactions. High-resolution transmission electron microscopy detection demonstrated that the silicon atoms and crystal lattice underneath the worn area maintained integral perfectly and thus further confirmed the tribochemical wear mechanism of the bare silicon. Finally, the role of water in the tribochemical wear of the bare silicon may be explained by the following three aspects: the hydroxylation by hydroxyl ions auto-ionized in water, the hydrolytic reaction of water molecules, and the dissolution of the tribochemical product SiO m H n in liquid water. With increasing RH, a greater water amount would adsorb to the Si/SiO 2 interface and induce a more serious tribochemical wear on the bare silicon surface. The results of this paper may provide further insight into the tribochemical removal mechanism of bare monocrystalline silicon and furnish the wider reaction cognition for chemical mechanical polishing.

  7. Efeito da porosidade nas propriedades mecânicas de uma alumina de elevada pureza Effect of porosity on mechanical properties of a high purity alumina

    Directory of Open Access Journals (Sweden)

    H. N. Yoshimura

    2005-09-01

    Full Text Available Uma alumina de elevada pureza dopada com MgO foi sinterizada entre 1300 e 1700 °C para preparação de corpos com diferentes porosidades. Foram determinadas a resistência à flexão em quatro pontos, a tenacidade à fratura pelo método SEVNB, a dureza Vickers, as velocidades sônicas (longitudinal e transversal e as constantes elásticas (ni, E, G e K pelo método do pulso-eco ultrassônico. Os resultados foram comparados com os modelos baseados em concentração de tensão (CT e modelos baseados na área sólida mínima (ASM. A porosidade das amostras variou entre 0,8% e 35%. Em geral, as propriedades diminuíram com o aumento da porosidade, sendo que a diminuição foi menos acentuada nas velocidades sônicas e mais acentuada na dureza. O coeficiente de Poisson só diminuiu em porosidade acima de 19%. O modelo analítico (CT que melhor se ajustou aos resultados dos módulos E e G foi o de Hashin-Rosen para configuração de poros cilíndricos alinhados transversalmente à tensão aplicada. A análise pelos modelos de ASM indicou que, até 19% de porosidade, o modelo de poros esféricos em arranjo cúbico foi predominante e, acima desta porosidade, atuou também o modelo de partículas esféricas em arranjo cúbico.A high purity alumina doped with MgO was sintered between 1300 and 1700 °C in order to prepare samples with different porosities. The following properties were determined: four-point flexural strength, fracture toughness, by SEVNB method, Vickers hardness, (transversal and longitudinal sonic velocities, and elastic constant (nu, E, G e K, by ultrasonic pulse-echo method. The results were compared with models based on stress concentration (SC and models based on minimum solid area (MSA. The porosity of the samples varied between 0.8% and 35%. Generally, the properties lowered with increasing porosity. This lowering was weaker in sonic velocities and stronger in hardness. The Poisson's ratio lowered only above 19% porosity. The

  8. Water Accommodation on Bare and Coated Ice

    Science.gov (United States)

    Kong, Xiangrui

    2015-04-01

    A good understanding of water accommodation on ice surfaces is essential for quantitatively predicting the evolution of clouds, and therefore influences the effectiveness of climate models. However, the accommodation coefficient is poorly constrained within the literature where reported values vary by up to three orders of magnitude. In addition, the complexity of the chemical composition of the atmosphere plays an important role in ice phase behavior and dynamics. We employ an environmental molecular beam (EMB) technique to investigate molecular water interactions with bare and impurity coated ice at temperatures from 170 K to 200 K. In this work, we summarize results of water accommodation experiments on bare ice (Kong et al., 2014) and on ice coated by methanol (Thomson et al., 2013), butanol (Thomson et al., 2013) and acetic acid (Papagiannakopoulos et al., 2014), and compare those results with analogous experiments using hexanol and nitric acid coatings. Hexanol is chosen as a complementary chain alcohol to methanol and butanol, while nitric acid is a common inorganic compound in the atmosphere. The results show a strong negative temperature dependence of water accommodation on bare ice, which can be quantitatively described by a precursor model. Acidic adlayers tend to enhance water uptake indicating that the system kinetics are thoroughly changed compared to bare ice. Adsorbed alcohols influence the temperature dependence of the accommodation coefficient and water molecules generally spend less time on the surfaces before desorbing, although the measured accommodation coefficients remain high and comparable to bare ice for the investigated systems. We conclude that impurities can either enhance or restrict water uptake in ways that are influenced by several factors including temperature and type of adsorbant, with potential implications for the description of ice particle growth in the atmosphere. This work was supported by the Swedish Research Council and

  9. The Liquid Argon Purity Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Adamowski, M.; Carls, B.; Dvorak, E.; Hahn, A.; Jaskierny, W.; Johnson, C.; Jostlein, H.; Kendziora, C.; Lockwitz, S.; Pahlka, B.; Plunkett, R.; Pordes, S.; Rebel, B.; Schmitt, R.; Stancari, M.; Tope, T.; Voirin, E.; Yang, T.

    2014-07-01

    The Liquid Argon Purity Demonstrator was an R&D test stand designed to determine if electron drift lifetimes adequate for large neutrino detectors could be achieved without first evacuating the cryostat. We describe here the cryogenic system, its operations, and the apparatus used to determine the contaminant levels in the argon and to measure the electron drift lifetime. The liquid purity obtained by this system was facilitated by a gaseous argon purge. Additionally, gaseous impurities from the ullage were prevented from entering the liquid at the gas-liquid interface by condensing the gas and filtering the resulting liquid before returning to the cryostat. The measured electron drift lifetime in this test was greater than 6 ms, sustained over several periods of many weeks. Measurements of the temperature profile in the argon, to assess convective flow and boiling, were also made and are compared to simulation.

  10. Síntese e caracterização de precursores de cério de alta pureza Synthesis and characterization of high purity cerium precursors

    Directory of Open Access Journals (Sweden)

    C. A. S. Queiroz

    2001-03-01

    Full Text Available Neste trabalho são destacadas as técnicas de separação e de purificação de terras raras por precipitação fracionada e troca iônica, além das técnicas usualmente utilizadas no controle analítico destes materiais. A aplicação destas técnicas é mostrada neste trabalho para a obtenção de óxido ou nitrato de cério com pureza > 99%. O principal objetivo é a obtenção de precursores à base de cério para o processamento de cerâmicas de zircônia-céria ou céria contendo terras raras. A disponibilidade de cloretos mistos, matéria-prima para a preparação de terras raras individuais, e o conhecimento das técnicas de separação, purificação e controle analítico de terras raras no IPEN, permite sua obtenção local para uso em pesquisa e desenvolvimento.In this work techniques of fractioned precipitation and ion exchange for separating and purifying rare earth elements are outlined. Other techniques usually utilized in the analytical control of these elements are also briefly discussed. The application of these techniques for the preparation of cerium nitrate or cerium oxide of > 99% purity are demonstrated. The main purpose is to obtain cerium precursors for the processing of zirconia-ceria or ceria-rare earth ceramic materials. The raw material availability in the form of mixed chlorides, and the knowledge of these techniques at IPEN allows for obtaining these precursors in the local market for research and development purposes.

  11. Role of water in the tribochemical removal of bare silicon

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Cheng; Xiao, Chen [Tribology Research Institute, National Traction Power Laboratory, Southwest Jiaotong University, Chengdu 610031 (China); Wang, Xiaodong [Center of Micro/Nano Science and Technology, Jiangsu University, Zhenjiang 212013 (China); Zhang, Peng; Chen, Lei; Qi, Yaqiong [Tribology Research Institute, National Traction Power Laboratory, Southwest Jiaotong University, Chengdu 610031 (China); Qian, Linmao, E-mail: linmao@swjtu.edu.cn [Tribology Research Institute, National Traction Power Laboratory, Southwest Jiaotong University, Chengdu 610031 (China)

    2016-12-30

    Highlights: • The wear of bare silicon against SiO{sub 2} micro-spherical tip is a tribochemical process with participation of water. • The water amount at Si/SiO{sub 2} interface plays a significant role on the wear of bare silicon. • The role of water relies on the hydroxylation by auto-ionized OH{sup −}, the hydrolysis of H{sub 2}O molecules, and the dissolution of SiO{sub m}H{sub n} in water. - Abstract: Nanowear tests of bare silicon against a SiO{sub 2} microsphere were conducted in air (relative humidity [RH] = 0%–89%) and water using an atomic force microscope. Experimental results revealed that the water played an important role in the tribochemical wear of the bare silicon. A hillock-like wear trace with a height of 0.7 nm was generated on the bare silicon surface in dry air. As the RH increased, the wear depth increased and reached the maximum level in water. Analysis of frictional dissipated energy suggested that the wear of the bare silicon was not dominated by mechanical interactions. High-resolution transmission electron microscopy detection demonstrated that the silicon atoms and crystal lattice underneath the worn area maintained integral perfectly and thus further confirmed the tribochemical wear mechanism of the bare silicon. Finally, the role of water in the tribochemical wear of the bare silicon may be explained by the following three aspects: the hydroxylation by hydroxyl ions auto-ionized in water, the hydrolytic reaction of water molecules, and the dissolution of the tribochemical product SiO{sub m}H{sub n} in liquid water. With increasing RH, a greater water amount would adsorb to the Si/SiO{sub 2} interface and induce a more serious tribochemical wear on the bare silicon surface. The results of this paper may provide further insight into the tribochemical removal mechanism of bare monocrystalline silicon and furnish the wider reaction cognition for chemical mechanical polishing.

  12. Ways for accurate analysis of high purity materials using the glow discharge mass spectrometry (GD-MS); Wege zur genauen Charakterisierung hochreiner Materialien mit der Glimmentladungs-Massenspektrometrie (GD-MS)

    Energy Technology Data Exchange (ETDEWEB)

    Gusarova, Tamara

    2010-04-14

    The main aim of this work consists in the investigation, development and application of improved possibilities of accurate analysis of high purity materials using the solid sample technique of Glow Discharge Mass Spectrometry (GD-MS), as well as in the sensitivity enhancement of GD Optical Emission Spectrometry (GD-OES) by implicating the hollow cathode effect. The emphasis of the PhD thesis consists in the accurate quantification for GD-MS. As appropriate certified reference materials (CRMs) for calibration are lacking in most cases an accurate quantification especially for trace elements mass fractions at {mu}g kg{sup -1} level can often not be achieved. To overcome this problem and to expand the possibilities of modern GD-MS hereby, synthetic standards were applied for calibration of both high resolution GD-MS instruments ''VG 9000'' and ''Element GD''. The standards were prepared by doping of matrix powder with trace element standard solutions followed by drying and pressing the doped powder to compact pellets. With the quantification approach worked out and described here accurate analysis results with small uncertainties can be achieved for most elements of periodic table in almost every matrix composition. Furthermore direct traceability of the analytical results to the International System of Units (SI) is provided ensuring their higher metrological quality. Numerous additional systematic investigations concerning the preparation of the synthetic standards and their properties were carried out. The results of calibration of GD-MS instruments with synthetic standards for Co (Co-C), Cu, In, Fe and Zn matrices were checked by measuring CRMs. These results were also contrasted with those of other quantification approaches, as usually used in GD-MS routine. The results achieved with synthetic standards had the highest accuracy. The successful participation in the round robin test CCQM-P107 between international

  13. Iodine Absorption Cells Purity Testing

    Directory of Open Access Journals (Sweden)

    Jan Hrabina

    2017-01-01

    Full Text Available This article deals with the evaluation of the chemical purity of iodine-filled absorption cells and the optical frequency references used for the frequency locking of laser standards. We summarize the recent trends and progress in absorption cell technology and we focus on methods for iodine cell purity testing. We compare two independent experimental systems based on the laser-induced fluorescence method, showing an improvement of measurement uncertainty by introducing a compensation system reducing unwanted influences. We show the advantages of this technique, which is relatively simple and does not require extensive hardware equipment. As an alternative to the traditionally used methods we propose an approach of hyperfine transitions’ spectral linewidth measurement. The key characteristic of this method is demonstrated on a set of testing iodine cells. The relationship between laser-induced fluorescence and transition linewidth methods will be presented as well as a summary of the advantages and disadvantages of the proposed technique (in comparison with traditional measurement approaches.

  14. Study of the recrystallization mechanisms of ultra-high purity iron doped with carbon, manganese and phosphorus; Etude des mecanismes de recristallisation dans le fer de ultra-haute purete dope en carbone, manganese et phosphore

    Energy Technology Data Exchange (ETDEWEB)

    Lesne, L.

    2000-07-04

    High purity steels have the potential to improve deep drawing properties for automotive applications. Understanding the influence of the chemical composition on the recrystallization mechanisms and on texture development should help to improve their properties. We have studied the influence of 10 ppm of carbon, 1000 ppm of manganese and 120 ppm of phosphorus on the recrystallization mechanisms of ultra-high purity iron (UHP iron > 99.997%). For this purpose we used 4 materials: one undoped (UHP), one doped with C, one doped with C, Mn and one doped With C, Mn, P. In order to restrict grain coarsening in the hot strips, hot rolling was performed in the ferritic region, in one pass of 80% thickness reduction. The hot bands were then fully recrystallized but exhibited non-isotropic textures, with in particular an intense Goss [110]<001> component for the doped materials. The hot-bands were subsequently cold rolled down to a thickness of 0.8 mm corresponding to a thickness reduction of 80%, and then continuously annealed at 10 deg. C/s. The recrystallization kinetics are delayed with the addition of doping elements. In particular, the incubation time for nucleation is shifted towards higher temperatures while the recrystallization velocity increases. The textures of the fully recrystallized materials exhibit a strong Goss component prejudicial for deep drawing properties. We have established that this component can only appear if coarse grains and carbon in solid solution were simultaneously present in the material before deformation. Characterisation of the cold deformed state enabled us to evaluate the energy stored during deformation as a function of the material composition and the grain orientation: - the overall stored energy increases with the doping elements content. - the stored energy in the {gamma} fibre grains is greater than in the {alpha} fibre grains: 30 J/mol for the {gamma} fibre instead of 5 J/mol for the {alpha} fibre, in the undoped UHP iron. In the

  15. Realization of the low background neutrino detector Double Chooz. From the development of a high-purity liquid and gas handling concept to first neutrino data

    International Nuclear Information System (INIS)

    Pfahler, Patrick

    2012-01-01

    Neutrino physics is one of the most vivid fields in particle physics. Within this field, neutrino oscillations are of special interest as they allow to determine driving oscillation parameters, which are collected as mixing angles in the leptonic mixing matrix. The exact knowledge of these parameters is the main key for the investigation of new physics beyond the currently known Standard Model of particle physics. The Double Chooz experiment is one of three reactor disappearance experiments currently taking data, which recently succeeded to discover a non-zero value for the last neutrino mixing angle Θ 13 . As successor of the CHOOZ experiment, Double Chooz will use two detectors with improved design, each of them now composed of four concentrically nested detector vessels each filled with different detector liquid. The integrity of this multi-layered structure and the quality of the used detector liquids are essential for the success of the experiment. Within this frame, the here presented work describes the production of two detector liquids, the filling and handling of the Double Chooz far detector and the installation of all necessary hardware components therefore. In order to meet the strict requirements existing for the detector liquids, all components were individually selected in an extensive material selection process at TUM, which compared samples from different companies for their key properties: density, transparency, light yield and radio purity. Based on these measurements, the composition of muon veto scintillator and buffer liquid were determined. For the production of the detector liquids, a simple surface building close to the far detector site was upgraded into a large-scale storage and mixing facility, which allowed to separately, mix, handle and store 90 m 3 of muon veto scintillator and 110 m 3 of buffer liquid. For the muon veto scintillator, a master-solution composed of 4800 l LAB, 180 kg PPO and 1.8 kg of bis/MSB was produced and

  16. Realization of the low background neutrino detector Double Chooz. From the development of a high-purity liquid and gas handling concept to first neutrino data

    Energy Technology Data Exchange (ETDEWEB)

    Pfahler, Patrick

    2012-12-17

    Neutrino physics is one of the most vivid fields in particle physics. Within this field, neutrino oscillations are of special interest as they allow to determine driving oscillation parameters, which are collected as mixing angles in the leptonic mixing matrix. The exact knowledge of these parameters is the main key for the investigation of new physics beyond the currently known Standard Model of particle physics. The Double Chooz experiment is one of three reactor disappearance experiments currently taking data, which recently succeeded to discover a non-zero value for the last neutrino mixing angle {Theta}{sub 13}. As successor of the CHOOZ experiment, Double Chooz will use two detectors with improved design, each of them now composed of four concentrically nested detector vessels each filled with different detector liquid. The integrity of this multi-layered structure and the quality of the used detector liquids are essential for the success of the experiment. Within this frame, the here presented work describes the production of two detector liquids, the filling and handling of the Double Chooz far detector and the installation of all necessary hardware components therefore. In order to meet the strict requirements existing for the detector liquids, all components were individually selected in an extensive material selection process at TUM, which compared samples from different companies for their key properties: density, transparency, light yield and radio purity. Based on these measurements, the composition of muon veto scintillator and buffer liquid were determined. For the production of the detector liquids, a simple surface building close to the far detector site was upgraded into a large-scale storage and mixing facility, which allowed to separately, mix, handle and store 90 m{sup 3} of muon veto scintillator and 110 m{sup 3} of buffer liquid. For the muon veto scintillator, a master-solution composed of 4800 l LAB, 180 kg PPO and 1.8 kg of bis/MSB was

  17. On line chemical analyzers for high purity steam and water, applied to steam power plants; Analizadores quimicos en linea para agua y vapor de alta pureza, aplicados a centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Perez, Ruth [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1989-12-31

    This article presents a general overview of the advances in the subject of on line analyzers of chemical parameters for high purity water and steam and specifies which ones are commercially available. Also are mentioned besides, the criteria nowadays applied for the selection of the sites for sample grabbing and the analysis that is necessary to perform in each point, depending on the power plant type and the treatment administered (phosphates-Ph coordinated or AVT treatment). [Espanol] El articulo presenta un panorama general de los avances que en materia de analizadores de parametros quimicos en linea para agua y vapor de alta pureza, y especifica cuales estan disponibles en forma comercial. Se citan, ademas los criterios que se aplican actualmente para seleccionar los puntos de toma de muestra y los analisis que es necesario efectuar en cada punto, dependiendo del tipo de central y del tratamiento que se le administre (fosfatos-pH coordinado o tratamiento AVT).

  18. Construction, assembling and operation of an equipment for sodium purity

    International Nuclear Information System (INIS)

    Becquart, E.T.; Botbol, J.; Echenique, P.N.; Fruchtenicht, F.W.; Gil, D.A.; Perillo, P.; Vardich, R.N.; Vigo, D.E.

    1993-01-01

    The purpose of this work is the production of high purity metallic sodium for bench-scale, research studies. A stainless steel equipment was built and assembled, including high vacuum, heating and cooling systems. It was satisfactorily operated in two successive steps, filtration and vacuum distillation, with a good yield. (Author). 5 refs., 5 figs

  19. A Process Concept for High-Purity Production of Amines by Transaminase-Catalyzed Asymmetric Synthesis: Combining Enzyme Cascade and Membrane-Assisted ISPR

    DEFF Research Database (Denmark)

    Börner, Tim; Rehn, Gustav; Grey, Carl

    2015-01-01

    For the amine transaminase (ATA)-catalyzed synthesis of chiral amines, the choice of donor substrate is of high importance for reaction and process design. Alanine was investigated as an amine donor for the reductive amination of a poorly water-soluble ketone (4-phenyl-2-butanone) in a combined...

  20. A summary of volatile impurity measurements and gas generation studies on MISSTD-1, a high-purity plutonium oxide produced by low-temperature calcination of plutonium oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Berg, John M. [Los Alamos National Laboratory; Narlesky, Joshua E. [Los Alamos National Laboratory; Veirs, Douglas K. [Los Alamos National Laboratory

    2012-06-08

    Plutonium dioxide of high specific surface area was subjected to long-term tests of gas generation in sealed containers. The material preparation and the storage conditions were outside the bounds of acceptable parameters defined by DOE-STD-3013-2012 in that the material was stabilized to a lower temperature than required and had higher moisture content than allowed. The data provide useful information for better defining the bounding conditions for safe storage. Net increases in internal pressure and transient increases in H{sub 2} and O{sub 2} were observed, but were well within the bounds of gas compositions previously shown to not threaten integrity of 3013 containers.

  1. Strengthening Purity: Moral Purity as a Mediator of Direct and Extended Cross-Group Friendships on Sexual Prejudice.

    Science.gov (United States)

    Vezzali, Loris; Brambilla, Marco; Giovannini, Dino; Paolo Colucci, Francesco

    2017-01-01

    The present research investigated whether enhanced perceptions of moral purity drive the effects of intergroup cross-group friendships on the intentions to interact with homosexuals. High-school students (N = 639) reported their direct and extended cross-group friendships with homosexuals as well as their beliefs regarding the moral character of the sexual minority. Participants further reported their desire to interact with homosexuals in the future. Results showed that both face-to-face encounters and extended contact with homosexuals increased their perceived moral purity, which in turn fostered more positive behavioral intentions. Results further revealed the specific role of moral purity in this sense, as differential perceptions along other moral domains (autonomy and community) had no mediation effects on behavioral tendencies toward homosexuals. The importance of these findings for improving intergroup relations is discussed, together with the importance of integrating research on intergroup contact and morality.

  2. CVD synthesis of high-purity multiwalled carbon nanotubes using CaCO 3 catalyst support for large-scale production

    Science.gov (United States)

    Couteau, E.; Hernadi, K.; Seo, J. W.; Thiên-Nga, L.; Mikó, Cs.; Gaál, R.; Forró, L.

    2003-08-01

    Multiwalled carbon nanotubes (MWCNTs) were synthesized in a catalytic reaction using CaCO 3 as catalyst support. Impregnated with conventional catalysts CaCO 3 enabled the production of MWCNTs in a fixed-bed flow reactor at relatively low reaction temperature. The purification was performed in one step: both metallic particles and catalyst support were dissolved in a diluted acid. Hence, disadvantages, namely multi-step processes and hazardous chemicals, were avoided. A further advantage of CaCO 3 support is efficient and stable growth of MWCNTs. First results obtained in our new rotary-tube oven indicated high quality and pure MWCNTs with a yield of 100 g/day by this method.

  3. Surpassing the current limitations of high purity H2production in microbial electrolysis cell (MECs): Strategies for inhibiting growth of methanogens.

    Science.gov (United States)

    Kadier, Abudukeremu; Kalil, Mohd Sahaid; Chandrasekhar, Kuppam; Mohanakrishna, Gunda; Saratale, Ganesh Dattatraya; Saratale, Rijuta Ganesh; Kumar, Gopalakrishnan; Pugazhendhi, Arivalagan; Sivagurunathan, Periyasamy

    2018-02-01

    Microbial electrolysis cells (MECs) are perceived as a potential and promising innovative biotechnological tool that can convert carbon-rich waste biomass or wastewater into hydrogen (H 2 ) or other value-added chemicals. Undesired methane (CH 4 ) producing H 2 sinks, including methanogens, is a serious challenge faced by MECs to achieve high-rate H 2 production. Methanogens can consume H 2 to produce CH 4 in MECs, which has led to a drop of H 2 production efficiency, H 2 production rate (HPR) and also a low percentage of H 2 in the produced biogas. Organized inference related to the interactions of microbes and potential processes has assisted in understanding approaches and concepts for inhibiting the growth of methanogens and profitable scale up design. Thus, here in we review the current developments and also the improvements constituted for the reduction of microbial H 2 losses to methanogens. Firstly, the greatest challenge in achieving practical applications of MECs; undesirable microorganisms (methanogens) growth and various studied techniques for eliminating and reducing methanogens activities in MECs were discussed. Additionally, this extensive review also considers prospects for stimulating future research that could help to achieve more information and would provide the focus and path towards MECs as well as their possibilities for simultaneously generating H 2 and waste remediation. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Bremsstrahlung from relativistic bare heavy ions: Nuclear and electronic contributions in amorphous and crystalline materials

    DEFF Research Database (Denmark)

    Jensen, Tue Vissing; Sørensen, Allan Hvidkjær

    2013-01-01

    A charged particle emits bremsstrahlung while traversing matter. We calculate the radiation cross section for bare heavy ions penetrating amorphous materials and single crystals at highly relativistic energies. The main component originates in scattering of the virtual photons of screened target...... in a pronounced directional dependence of the energy loss of bare heavy ions at extreme relativistic energies....

  5. Production d'isobutène de haute pureté par décomposition du MTBE High-Purity Isobutene Production from Mtbe

    Directory of Open Access Journals (Sweden)

    Meunier P. B.

    2006-11-01

    decomposition is catalyzed by solids with an acid nature. It has mainly been examined on catalysts of the sulfonic-resin type, but solid acid catalysts have recently appeared (zeolites, silica-alumina, supported phosphoric acid, etc. . The different types of catalysts used are examined for the principal reaction and secondary reactions. The formulation of the catalyst and the nature of the active acid sites (Brönsted or Lewis have great influence on the reaction. Data from the literature mainly concern catalysts of the resin type with Brönsted acidity. Concerning catalysts of the oxide type, mention is made of Lewis acid sites catalyzing the principal reaction. The species adsorbed, the mechanisms and kinetic investigations of MTBE decomposition have mainly been examined for sulfonic resins. The most probable mechanisms (mechanism B, page 371 is the following one :(a Ether adsorption on a double center without dissociation. (b Surface reaction between adsorbed ether and a free active center, to give rise to isobutene adsorbed on a double center without dissociation and methanol adsorbed on a single center. This stage is the one that limits the process from the kinetic standpoint. (c Desorption of isobutene and methanol. The corresponding rate equation is given in Table III, and the adsorbed species are given on page . For solid acid catalysts, few data concerning the kinetics are available in the literature. A single equation (Eq. 4, page 371, which was determined experimentally on a gamma-AI2O3 catalyst modified on the surface by silica, is proposed. On a gamma-AI2O3 catalyst, the inhibiting influence of water has been shown for high contents. Secondary reactions are mainly due to the presence of Brönsted acidity. Indeed, the dimerization and trimerization of isobutene involve mechanisms that necessitate going via a carbonium-ion intermediary on Brönsted acid sites (mechanisms on pages 372 and 377. Likewise, the dehydration of methanol is enhanced by the presence of

  6. Chemical analysis of high purity graphite

    International Nuclear Information System (INIS)

    1993-03-01

    The Sub-Committee on Chemical Analysis of Graphite was organized in April 1989, under the Committee on Chemical Analysis of Nuclear Fuels and Reactor Materials, JAERI. The Sub-Committee carried out collaborative analyses among eleven participating laboratories for the certification of the Certified Reference Materials (CRMs), JAERI-G5 and G6, after developing and evaluating analytical methods during the period of September 1989 to March 1992. The certified values were given for ash, boron and silicon in the CRM based on the collaborative analysis. The values for ten elements (Al, Ca, Cr, Fe, Mg, Mo, Ni, Sr, Ti, V) were not certified, but given for information. Preparation, homogeneity testing and chemical analyses for certification of reference materials were described in this paper. (author) 52 refs

  7. Ultra high purity, dimensionally stable INVAR 36

    Science.gov (United States)

    Sokolowski, Witold M. (Inventor); Lane, Marc S. (Inventor); Hsieh, Cheng H. (Inventor); Odonnell, Timothy P. (Inventor)

    1995-01-01

    An INVAR 36 material having long-term dimensional stability is produced by sintering a blend of powders of nickel and iron under pressure in an inert atmosphere to form an alloy containing less than 0.01 parts of carbon and less than 0.1 part aggregate and preferably 0.01 part individually of Mn, Si, P, S and Al impurities. The sintered alloy is heat treated and slowly and uniformly cooled to form a material having a coefficient of thermal expansion of less than 1 ppm/C and a temporal stability of less than 1 ppm/year.

  8. Study of important parameters on the irradiation of 124Xe, to improve the production of 123I with high purity using the Cyclone-30 cyclotron at IPEN-CNEN/SP

    International Nuclear Information System (INIS)

    Sumiya, Luiz Carlos do Amaral

    2006-01-01

    The development of diagnosis equipment and therapy procedures in nuclear medicine depends on the availability of commercial radioisotopes. IPEN is the most important institution that provides radioisotopes for national market. In order to achieve this function, IPEN had invested in the acquisition of a 30 MeV Cyclone-30 cyclotron to produce mainly 18 F, 67 Ga, 201 Tl and 123 I. The 123 I production is the aim of the present work. With the 123 I routine production data obtained by proton irradiation of Xe targets with an enrichment greater than 99.8%, it was possible to identify the important parameters that have direct influence on the production yield of high purity degree 123 I. Even though the methodology for the commercial production of 123 I, there are an scarcity of operational parameters data for this task. In this work the evaluated parameters were: 124 Xe pressure, proton beam quality, irradiation time, operational temperature of the irradiation system under irradiation, waiting time to obtain 123 I, temperature of washing solution and the impact of the internal Ni coating in the target. With the obtained results it was possible to modify the operational conditions for routine production and increasing the efficiency in about 30%. (author)

  9. The effect of incremental gamma-ray doses and incremental neutron fluences upon the performance of self-biased sup 1 sup 0 B-coated high-purity epitaxial GaAs thermal neutron detectors

    CERN Document Server

    Gersch, H K; Simpson, P A

    2002-01-01

    High-purity epitaxial GaAs sup 1 sup 0 B-coated thermal neutron detectors advantageously operate at room temperature without externally applied voltage. Sample detectors were systematically irradiated at fixed grid locations near the core of a 2 MW research reactor to determine their operational neutron dose threshold. Reactor pool locations were assigned so that fast and thermal neutron fluxes to the devices were similar. Neutron fluences ranged between 10 sup 1 sup 1 and 10 sup 1 sup 4 n/cm sup 2. GaAs detectors were exposed to exponential fluences of base ten. Ten detector designs were irradiated and studied, differentiated between p-i-n diodes and Schottky barrier diodes. The irradiated sup 1 sup 0 B-coated detectors were tested for neutron detection sensitivity in a thermalized neutron beam. Little damage was observed for detectors irradiated at neutron fluences of 10 sup 1 sup 2 n/cm sup 2 and below, but signals noticeably degraded at fluences of 10 sup 1 sup 3 n/cm sup 2. Catastrophic damage was appare...

  10. Contribution of the low cycle fatigue on ultra high purity Ni-Cr-Fe alloys and on Ni monocrystals to the understanding of the hydrogen role in stress corrosion cracking for the alloys 600 and 690

    International Nuclear Information System (INIS)

    Renaudot, N.

    1999-06-01

    We discuss the role of hydrogen in cracking of Ni base alloys used for pressurised water reactor (PWR) primary tubes (alloy 600 and 690). Cracking can be explained by a Stress Corrosion Cracking (SCC) phenomenon. For this purpose, Low cycle fatigue (R = - 1) under cathodic charging at room temperature is conducted to study hydrogen effects on propagation of cracks mechanically initiated by the formation of Persistent Slip Bands (PSB). Low cycle fatigue on Ultra High Purity specimens (Ni, alloy 600 and 690) reveals the very important hydrogen effect on crack propagation rate, whatever the Cr content in the Ni base alloy. If Cr seems to have an effect over-hydrogen penetration in specimens (by a protective film formation), it have no beneficial effect when hydrogen have diffused ahead of a crack tip. Propagation rates (transgranular or intergranular) are highly increased, no matter of the absence of impurities like sulphur. Then, in PWR, the difference in the behaviour of alloy 600 and 690 could be due to a slower microcrack propagation rate for alloy 690. Protective films could play an important role in this difference, which is to study. Low cycle fatigue on Ni single crystals oriented for single slip shows, for the first time on bulk specimen, a macroscopic softening which can be explained. by hydrogen-dislocation interactions. Moreover, a simple quantitative model based on these interactions results in the same softening as the one observed experimentally. These results allow to validate experimentally one of the most important steps in the 'Corrosion Enhanced Plasticity (CEP) model', i.e. the softening ahead of a stress corrosion crack tip by hydrogen dislocation interactions. This is of importance because this model can explain cracking in numerous FCC materials-environment couple. (author)

  11. Prognostic Relevance of Tumor Purity and Interaction with MGMT Methylation in Glioblastoma.

    Science.gov (United States)

    Schulze Heuling, Eva; Knab, Felix; Radke, Josefine; Eskilsson, Eskil; Martinez-Ledesma, Emmanuel; Koch, Arend; Czabanka, Marcus; Dieterich, Christoph; Verhaak, Roel G; Harms, Christoph; Euskirchen, Philipp

    2017-05-01

    Promoter methylation status of O-6-methylguanine-DNA methyltransferase (MGMT), a DNA repair enzyme, is a critical biomarker in glioblastoma (GBM), as treatment decisions and clinical trial inclusion rely on its accurate assessment. However, interpretation of results is complicated by poor interassay reproducibility as well as a weak correlation between methylation status and expression levels of MGMT. This study systematically investigates the influence of tumor purity on tissue subjected to MGMT analysis. A quantitative, allele-specific real-time PCR (qAS-PCR) assay was developed to determine genotype and mutant allele frequency of telomerase promoter (pTERT) mutations as a direct measure of tumor purity. We studied tumor purity, pTERT mutation by Sanger sequencing, MGMT methylation by pyrosequencing, IDH1 mutation status, and clinical parameters in a cohort of high-grade gliomas ( n = 97). The qAS-PCR reliably predicted pTERT genotype and tumor purity compared with independent methods. Tumor purity positively and significantly correlated with the extent of methylation in MGMT methylated GBMs. Extent of MGMT methylation differed significantly with respect to pTERT mutation hotspot (C228T vs. C250T). Interestingly, frontal lobe tumors showed greater tumor purity than those in other locations. Above all, tumor purity was identified as an independent prognostic factor in GBM. In conclusion, we determined mutual associations of tumor purity with MGMT methylation and pTERT mutations and found that the extent of MGMT methylation reflects tumor purity. In turn, tumor purity is prognostic in IDH1 wild-type GBM. Implications: Tumor purity is an independent prognostic marker in glioblastoma and is associated with the extent of MGMT methylation. Mol Cancer Res; 15(5); 532-40. ©2017 AACR . ©2017 American Association for Cancer Research.

  12. Hydrodynamic behavior of a bare rod bundle

    International Nuclear Information System (INIS)

    Bartzis, J.G.; Todreas, N.E.

    1977-06-01

    The temperature distribution within the rod bundle of a nuclear reactor is of major importance in nuclear reactor design. However temperature information presupposes knowledge of the hydrodynamic behavior of the coolant which is the most difficult part of the problem due to complexity of the turbulence phenomena. In the present work a 2-equation turbulence model--a strong candidate for analyzing actual three dimensional turbulent flows--has been used to predict fully developed flow of infinite bare rod bundle of various aspect ratios (P/D). The model has been modified to take into account anisotropic effects of eddy viscosity. Secondary flow calculations have been also performed although the model seems to be too rough to predict the secondary flow correctly. Heat transfer calculations have been performed to confirm the importance of anisotropic viscosity in temperature predictions. All numerical calculations for flow and heat have been performed by two computer codes based on the TEACH code. Experimental measurements of the distribution of axial velocity, turbulent axial velocity, turbulent kinetic energy and radial Reynolds stresses were performed in the developing and fully developed regions. A 2-channel Laser Doppler Anemometer working on the Reference mode with forward scattering was used to perform the measurements in a simulated interior subchannel of a triangular rod array with P/D = 1.124. Comparisons between the analytical results and the results of this experiment as well as other experimental data in rod bundle array available in literature are presented. The predictions are in good agreement with the results for the high Reynolds numbers

  13. Improvement in fuel utilization in pressurized heavy water reactors due to increased heavy water purity

    International Nuclear Information System (INIS)

    Balakrishnan, M.R.

    1991-01-01

    This paper reports that in a pressurized heavy water reactor (PHWR), the reactivity of the reactor and, consequently, the discharge burnup of the fuel depend on the isotopic purity of the heavy water used in the reactor. The optimal purity of heavy water used in PHWRs, in turn, depends on the cost of fabricated uranium fuel and on the incremental cost incurred in improving the heavy water purity. The physics and economics aspects of the desirability of increasing the heavy water purity in PHWRs in India were first examined in 1978. With the cost data available at that time, it was found that improving the heavy water purity from 99.80% to 99.95% was economically attractive. The same problem is reinvestigated with current cost data. Even now, there is sufficient incentive to improve the isotopic purity of heavy water used in PHWRs. Admittedly, the economic advantage that can be derived depends on the cost of the fabricated fuel. Nevertheless, irrespective of the economics, there is also a fairly substantial saving in natural uranium. That the increase in the heavy water purity is to be maintained only in the low-pressure moderator system, and not in the high-pressure coolant system, makes the option of achieving higher fuel burnup with higher heavy water purity feasible

  14. Policosanol extraction from beeswax and improvement of the purity

    Directory of Open Access Journals (Sweden)

    Srisaipet Anakhaorn

    2017-01-01

    Full Text Available Policosanol is a mixture of high molecular weight aliphatic long chain alcohols (20-36 carbon atoms. It has been use in pharmaceutical composition and food supplements. This research aimed to isolate and improve the purity of policosanol extracted from beeswax. Triglycerides and other impurities were eliminated from beeswax by refluxing with hexane followed by isopropanol. The purified beeswax was hydrolyzed by refluxing with 1 M ethanolic NaOH for 2 hours. Purification of policosanol was performed by extracting the hydrolyzed product with acetone at 50-60 °C for 3 hours and it was stored at 4 °C for precipitation. The precipitate was refluxed with heptanes followed by washing with hot water. The heptanes layer was kept for policosanol precipitation at 4 °C. The purity of policosanol was confirmed by TLC and high performance liquid chromatography (HPLC. The yield of purified policosanol was 13.23-13.89 %.

  15. Electron beam control for barely separated beams

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, David R.; Ament, Lucas J. P.

    2017-04-18

    A method for achieving independent control of multiple beams in close proximity to one another, such as in a multi-pass accelerator where coaxial beams are at different energies, but moving on a common axis, and need to be split into spatially separated beams for efficient recirculation transport. The method for independent control includes placing a magnet arrangement in the path of the barely separated beams with the magnet arrangement including at least two multipole magnets spaced closely together and having a multipole distribution including at least one odd multipole and one even multipole. The magnetic fields are then tuned to cancel out for a first of the barely separated beams to allow independent control of the second beam with common magnets. The magnetic fields may be tuned to cancel out either the dipole component or tuned to cancel out the quadrupole component in order to independently control the separate beams.

  16. Hvorfor siger vi ikke bare ugh?!

    DEFF Research Database (Denmark)

    Pálfi, Loránd-Levente

    2009-01-01

    Det danske sprog er ramt af en flerdobbelt katastrofe: De unge i folkeskolerne og gymnasierne taler og skriver et stadigt dårligere dansk, og forskningen i dansk sprog går i stå. Og Dansk Sprognævn, som burde stå vagt om sproget, lader ikke bare stå til, men ophæver forfaldet til lov. Er en "B...

  17. Civilian peacekeeping: a barely tapped ressource

    OpenAIRE

    2010-01-01

    Christine Schweitzer: Introduction - Civilian peacekeeping. A barely tapped ressource (7-16); Rolf Carrière: The world needs 'another peacekeeping' (17-24); Tim Wallis: Best practices for unarmed civilian peacekeeping (25-34); Rachel Julians: Peacekeeping with nonviolence: protection strategies for sustainable peace (35-42); Christine Schweitzer: Humanitarian protection as an additional function of humanitarian, development and peace projects - or rather a task requiring experts? (43-52); Chr...

  18. Tumor targeting efficiency of bare nanoparticles does not mean the efficacy of loaded anticancer drugs: importance of radionuclide imaging for optimization of highly selective tumor targeting polymeric nanoparticles with or without drug.

    Science.gov (United States)

    Lee, Beom Suk; Park, Kyeongsoon; Park, Sangjin; Kim, Gui Chul; Kim, Hyo Jung; Lee, Sangjoo; Kil, Heeseup; Oh, Seung Jun; Chi, Daeyoon; Kim, Kwangmeyung; Choi, Kuiwon; Kwon, Ick Chan; Kim, Sang Yoon

    2010-10-15

    The better understanding of polymeric nanoparticles as a drug delivery carrier is a decisive factor to get more efficient therapeutic response in vivo. Here, we report the non-invasive imaging of bare polymeric nanoparticles and drug-loaded polymeric nanoparticles to evaluate biodistribution in tumor bearing mice. To make nano-sized drug delivery carrier, glycol chitosan was modified with different degrees of hydrophobic N-acetyl histidine (NAcHis-GC-1, -2, and -3). The biodistribution of polymeric nanoparticles and drug was confirmed by using gamma camera with (131)I-labeled NAcHis-GC and (131)I-labeled doxorubicin (DOX) and by using in vivo live animal imaging with near-infrared fluorescence Cy5.5-labeled NAcHis-GC. Among bare nanoparticles, NAcHis-GC3 (7.8% NAcHis content) showed much higher tumor targeting efficiency than NAcHis-GC1 (3.3% NAcHis content) and NAcHis-GC2 (6.8% NAcHis content). In contrast, for drug-loaded nanoparticles, DOX-NAcHis-GC1 displayed two-fold higher tumor targeting property than DOX-NAcHis-GC3. These data imply that the biodistribution and tumor targeting efficiency between bare and drug-loaded nanoparticles may be greatly different. Therapeutic responses for NAcHis-GC nanoparticles after drug loading were also evaluated. In xenograft animal model, we could find out that DOX-NAcHis-GC1 with higher tumor targeting of DOX has more excellent therapeutic effect than DOX-NAcHis-GC3 and free DOX. These results mean that the hydrophobic core stability might be a critical factor for tumor targeting efficiency of nanoparticles. The present study indicates that by using molecular imaging, we can select more appropriate nanoparticles with the highest tumor targeting properties, leading to exerting more excellent therapeutic results in cancer therapy. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. Efficacy of a high-purity factor IX concentrate in hemophilia B patients undergoing surgery Eficácia do concentrado de alta pureza do fator IX em pacientes cirúrgicos portadores de hemofilia B

    Directory of Open Access Journals (Sweden)

    Vesa Rasi

    2002-04-01

    Full Text Available A plasma derived, high purity, solvent-detergent treated and subsequently nanofiltered factor IX concentrate (BEMOFIL was evaluated in 19 hemophilia B patients, including four with severe, thirteen with mild or moderate type of disease and two hemophilia B carriers undergoing 31 surgical procedures. The mean in vivo recovery was 52 %, range 36 - 76 %. The mean preoperative plasma factor IX activity after the initial loading dose was 0.86 IU mL-1, range 0.59 - 1.32 IU mL-1. In eight major orthopedic procedures, the mean usage of factor IX was 44600 IU or 574 IU kg-1 during the hospital stay, mean 11.6 days. Thromboprophylaxis was not used. The hemostatic efficacy was evaluated good in all cases and there were no thromboembolic complications. In conclusion, BEMOFIL used as bolus dosing was found to be safe and effective in achieving hemostasis in subjects with hereditary F IX deficiency undergoing surgery.O concentrado de fator IX ( Bemofil , um derivado plasmático de alta pureza tratado com solventes- detergente e nano-filtrado , foi avaliado em 19 pacientes portadores de Hemofilia B .Quatro pacientes apresentavam a forma grave da moléstia, 13 a forma leve e moderada e dois portadores em um total de 31 atos cirúrgicos.A recuperação média "in vivo" foi de 52% (36-76%. A atividade plasmática média pré-operatória do fator IX após a dose inicial foi de 0,86 UI ml -1 , média de 0,59 - 1,32 UI ml-1. Em oito procedimentos ortopédicos extensos , a média de utilização do fator IX foi de 44.600 UI ou 574 UI kg -1 durante a hospitalização que teve a média de 11,6 dias. A tromboprofilaxia não foi utilizada. A eficácia hemostática avaliada em todos os casos foi boa ,e não ocorreu nenhum tipo de complicação tromboembólica. Concluímos que o Bemofil em bolus foi considerado seguro e eficaz para a hemostasia em pacientes portadores de hemofilia B que necessitam de um procedimento cirúrgico.

  20. Purity assessment of condensed tannin fractions by nuclear magnetic resonance (NMR) spectroscopy

    Science.gov (United States)

    Unambiguous investigation of condensed tannin (CT) structure-activity relationships in biological systems requires the use of highly enriched CT fractions of defined chemical purity. Purification of CTs from Sorghum bicolor, Trifolium repens, Theobroma cacao, Lespedeza cuneata, Lotus pedunculatus, a...

  1. Bare Beach Logistics Over-the-Shore: An Outdated Concept?

    National Research Council Canada - National Science Library

    Pehrson, Christopher J

    2000-01-01

    This paper is a critical review of bare beach logistics over-the-shore (LOTS) operations. It examines the utility of the bare beach and asks if this method of LOTS is still viable for today's military...

  2. Evaluation of measurement uncertainty for purity of a monoterpenic acid by small-scale coulometry

    Science.gov (United States)

    Norte, L. C.; de Carvalho, E. M.; Tappin, M. R. R.; Borges, P. P.

    2018-03-01

    Purity of the perylic acid (HPe) which is a monoterpenic acid from natural product (NP) with anti-inflammatory and anticancer properties was analyzed by small-scale coulometry (SSC), due to the low availability of HPe on the pharmaceutic market and its high cost. This work aims to present the evaluation of the measurements uncertainty from the purity of HPe by using SSC. Coulometric mean of purity obtained from 5 replicates resulted in 94.23% ± 0.88% (k = 2.06, for an approximately 95% confidence level). These studies aim in the future to develop the production of certified reference materials from NPs.

  3. Algebraic approach to bare nucleon matrix elements of quark operators

    International Nuclear Information System (INIS)

    Zschocke, Sven; Kaempfer, Burkhard; Plunien, Guenter

    2005-01-01

    An algebraic method for evaluating bare nucleon matrix elements of quark operators is proposed. Thereby, bare nucleon matrix elements are traced back to vacuum matrix elements. The method is similar to the soft pion theorem. Matrix elements of two-quark, four-quark and six-quark operators inside the bare nucleon are considered

  4. Ikke bare porno på mobilen

    DEFF Research Database (Denmark)

    Andersen, Tem Frank

    2013-01-01

    Den britiske børne- og ungdomsforsker professor Sonia Livingstone ved London School of Economics viser gennem en række interviews, at billeder af eksplicitte sexhandlinger er en velkendt del af den ungdommelige cirkulation af ’hverdagspornografisk’ materiale (Ringrose et al. 2012). ’Sexting’ er a...... altså ikke bare porno på en mobilplatform. Det er handlinger og værgestrategier, som unge piger er nødt til at forholde sig til i hverdagen, mens drengene umiddelbart ser ud til at slippe relativt let udenom den chikane, der kan ligge i ’sexting’....

  5. Almost purity for overconvergent Witt vectors

    DEFF Research Database (Denmark)

    Davis, Christopher James; Kedlaya, Kiran

    2015-01-01

    In a previous paper, we stated a general almost purity theorem in the style of Faltings: if R is a ring for which the Frobenius maps on finite p-typical Witt vectors over R are surjective, then the integral closure of R   in a finite étale extension of R[p−1]R[p−1] is “almost” finite étale over R......  . Here, we use almost purity to lift the finite étale extension of R[p−1]R[p−1] to a finite étale extension of rings of overconvergent Witt vectors. The point is that no hypothesis of p-adic completeness is needed; this result thus points towards potential global analogues of p  -adic Hodge theory...

  6. Imaging Scanner Usage in Radiochemical Purity Test

    International Nuclear Information System (INIS)

    Norhafizah Othman; Yahaya Talib; Wan Hamirul Bahrin Wan Kamal

    2011-01-01

    Imaging Scanner model BIOSCAN AR-2000 has been used in the radiochemical purity test for the product of Mo-99/ Tc-99m generator. Result from this test was produced directly where the percentage of pertechnetate was calculated based on width peak area by thin layer chromatography. This paperwork will explain the function, procedure, calibration of the instrument and discussed the advantages compared to the previous method. (author)

  7. Initial Stages of Recrystallization in Aluminum of Commercial Purity

    DEFF Research Database (Denmark)

    Hansen, Niels; Bay, Bent

    1979-01-01

    In commercial aluminum with a purity of 99.4 pct, the formation and growth of recrystallization nuclei were studied by techniques such asin-situ annealing in a high voltage electron microscope, transmission electron microscopy and light microscopy. Sample parameters were the initial grain size (370...... by the FeAl3 particles present in the commercial aluminum as impurities. The nucleation temperatures determined by high voltage electron microscopy and transmission electron microscopy decrease markedly when the initial grain size is decreased both after 50 and 90 pct cold rolling; a less pronounced...

  8. Adherence of Staphylococcus aureus to Dyneema Purity® Patches and to Clinically Used Cardiovascular Prostheses.

    Directory of Open Access Journals (Sweden)

    Amir Basir

    Full Text Available Various materials that are used for vascular and heart valve prostheses carry drawbacks: some require anticoagulant drugs or have moderate durability; others are not suitable for endovascular treatment. These prostheses are associated with bacterial infections. A material potentially suitable for prostheses is Dyneema Purity®, made of ultra-high-molecular-weight polyethylene. Dyneema Purity® fibers are very thin, flexible, resistant to fatigue and abrasion, and have high strength. S. aureus adherence to Dyneema Purity® was tested and compared with currently used cardiovascular prostheses. We compared adhesion of S. aureus to Dyneema Purity® (1 membrane-based and 1 yarn-composed patch with 5 clinically used yarn-composed polyester and membrane-based expanded polytetrafluoroethylene patches. Patches were contaminated with S. aureus bacteria and bacterial adherence was quantified. S. aureus adherence was also visualized in flow conditions. Overall, bacterial adherence was higher on yarn-composed prosthesis materials, with a rough surface, than on the membrane-based materials, with a smooth surface. Adherence to Dyneema Purity® materials was non-inferior to the currently used materials. Therefore, patches of Dyneema Purity® might be attractive for use in cardiovascular applications such as catheter-based heart valves and endovascular prostheses by their good mechanical properties combined with their noninferiority regarding bacterial adhesion.

  9. Do Bare Rocks Exist on the Moon?

    Science.gov (United States)

    Allen, Carlton; Bandfield, Joshua; Greenhagen, Benjamin; Hayne, Paul; Leader, Frank; Paige, David

    2017-01-01

    Astronaut surface observations and close-up images at the Apollo and Chang'e 1 landing sites confirm that at least some lunar rocks have no discernable dust cover. However, ALSEP (Apollo Lunar Surface Experiments Package) measurements as well as astronaut and LADEE (Lunar Atmosphere and Dust Environment Explorer) orbital observations and laboratory experiments possibly suggest that a fine fraction of dust is levitated and moves across and above the lunar surface. Over millions of years such dust might be expected to coat all exposed rock surfaces. This study uses thermal modeling, combined with Diviner (a Lunar Reconnaissance Orbiter experiment) orbital lunar eclipse temperature data, to further document the existence of bare rocks on the lunar surface.

  10. High-performance enantiomer separation of nonsteroidal anti-inflammatory drugs (NSAIDs) by 3 μm reversed-phase chiral columns and application to the optical purity testing of naproxen drug substances and its formulations.

    Science.gov (United States)

    Tanaka, Moe; Nagamatsu, Kumi; Nishi, Hiroyuki

    2014-01-01

    The enantiomer separation of five nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, ketoprofen (KP) and naproxen (NX), which are included in The Japanese Pharmacopoeia 16th edition (JP16), was investigated by employing four kinds of 3 μm reversed-phase chiral columns (AD-3R, AS-3R, OD-3R and OJ-3R). Except for KP, the enantiomers of four NSAIDs were successfully separated by one of the four columns. Among five NSAIDs, only NX has been used as a single enantiomer (S-form, active form) in the clinical field (JP16); therefore, optical purity testing method of NX is required for its quality evaluation. Among four CSPs, the method was developed by using an AS-3R column, which showed good enantioselectivity for NX enantiomers. By optimizing the conditions, the resolution (Rs) of 2.55 was obtained for NX enantiomers within approximately 6 min. The minor enantiomer R-form eluted before the main active enantiomer S-form. Finally, the developed method was applied to the optical purity testing of NX active pharmaceutical ingredients (APIs), and its formulations (tablet and capsule). Other than the minor enantiomer (R-form, inactive form, 0.21 - 0.78%), normal (not chiral) impurities at levels of 0.01-0.3% were simultaneously separated and determined by the method, showing an excellent separation capability of the method for those impurities including the minor enantiomer. The content uniformity test of the NX tablet according to JP16 was also successfully performed by the method with the AS-3R column. Normal phase separation with two chiral columns (AD-H and OD-H) and capillary electrophoretic (CE) separation were also investigated for five NSAIDs enantiomers to discuss the enantioselectivity.

  11. An Improved Shock Model for Bare and Covered Explosives

    Science.gov (United States)

    Scholtes, Gert; Bouma, Richard

    2017-06-01

    TNO developed a toolbox to estimate the probability of a violent event on a ship or other platform, when the munition bunker is hit by e.g. a bullet or fragment from a missile attack. To obtain the proper statistical output, several millions of calculations are needed to obtain a reliable estimate. Because millions of different scenarios have to be calculated, hydrocode calculations cannot be used for this type of application, but a fast and good engineering solutions is needed. At this moment the Haskins and Cook-model is used for this purpose. To obtain a better estimate for covered explosives and munitions, TNO has developed a new model which is a combination of the shock wave model at high pressure, as described by Haskins and Cook, in combination with the expanding shock wave model of Green. This combined model gives a better fit with the experimental values for explosives response calculations, using the same critical energy fluence values for covered as well as for bare explosives. In this paper the theory is explained and results of the calculations for several bare and covered explosives will be presented. To show this, the results will be compared with the experimental values from literature for composition B, Composition B-3 and PBX-9404.

  12. The bare parameters of Gribov's Langrangian are understood and determined

    International Nuclear Information System (INIS)

    Bishari, M.

    1977-01-01

    In the context of the ''1/N Dual Unitarization'' scheme, an explicit dynamical study of the triple bare pomeron mechanism which governs the interaction term in Gribov's Lagrangian is presented. Together with the previously established bare pomeron slope and intercept, controlling respectively, the kinetic and mass terms in Gribov's Lagrangian, this work demonstrates the viability of the ''1/N Dual Unitarization'' approach for a field theory of interaction bare pomerons. (author)

  13. Purity and Enrichment of Laser-Microdissected Midbrain Dopamine Neurons

    Directory of Open Access Journals (Sweden)

    Amanda L. Brown

    2013-01-01

    Full Text Available The ability to microdissect individual cells from the nervous system has enormous potential, as it can allow for the study of gene expression in phenotypically identified cells. However, if the resultant gene expression profiles are to be accurately ascribed, it is necessary to determine the extent of contamination by nontarget cells in the microdissected sample. Here, we show that midbrain dopamine neurons can be laser-microdissected to a high degree of enrichment and purity. The average enrichment for tyrosine hydroxylase (TH gene expression in the microdissected sample relative to midbrain sections was approximately 200-fold. For the dopamine transporter (DAT and the vesicular monoamine transporter type 2 (Vmat2, average enrichments were approximately 100- and 60-fold, respectively. Glutamic acid decarboxylase (Gad65 expression, a marker for GABAergic neurons, was several hundredfold lower than dopamine neuron-specific genes. Glial cell and glutamatergic neuron gene expression were not detected in microdissected samples. Additionally, SN and VTA dopamine neurons had significantly different expression levels of dopamine neuron-specific genes, which likely reflects functional differences between the two cell groups. This study demonstrates that it is possible to laser-microdissect dopamine neurons to a high degree of cell purity. Therefore gene expression profiles can be precisely attributed to the targeted microdissected cells.

  14. Evaluation of C18 monolithic columns for radiochemical purity measurement.

    Science.gov (United States)

    Schenk, David J; Welch, Christopher J; Antonucci, Vincent

    2016-08-01

    Speeding the analysis of reaction aliquots, high-performance liquid chromatography (HPLC) fractions and final products continue to be an area of great interest in the study of radiopharmaceuticals. Translating recently developed rapid HPLC and ultra high-performance liquid chromatography analysis approaches to radio-HPLC can sometimes be fraught with peril, owing to specific peculiarities of online radiochemical chromatographic detection (notably, a proportionally large system volume for the radio-HPLC detector). In this study, we investigate an alternate approach for rapid radio-HPLC analysis where a 150-cm C18 monolithic column is used with a 15-min run time. To ascertain this method's ability to distinguish between radiolabeled compounds with acceptable (≥97%) and unacceptable purity, the results were compared with results from a conventional HPLC 45-min method using a 25-cm C18 column, where a large radiodetector cell volume is of lower impact. Overall, for the 54 radiolabeled compounds assayed by the two methods, there were similar measured radiochemical purities, but cases were also found where there were significantly large differences between the results (>1%). A calculated confidence of ~85% was found for the 15-min monolithic method's ability to accurately reproduce the corresponding result from the 25-cm column method. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Switching from EPA + DHA (Omega-3-acid Ethyl Esters) to High-Purity EPA (Icosapent Ethyl) in a Statin-Treated Patient with Persistent Dyslipidemia and High Cardiovascular Risk: A Case Study

    OpenAIRE

    James R. Crandell

    2016-01-01

    Cardiovascular (CV) risk may remain despite statin treatment, and there is a need to address this risk with add-on therapy. The lipid effects of two different prescription omega-3 fatty acid therapies are described in a 55-year-old statin- and niacin-treated female with severe dyslipidemia and high CV risk. The patient was initially treated with omega-3-acid ethyl esters (eicosapentaenoic acid [EPA] and docosahexaenoic acid) 4 g/day. Due to persistently elevated low-density lipoprotein choles...

  16. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Ridge, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} x 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover, the valves failed and UF{sub 6} was released. The remaining 6 cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  17. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Rige, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover the valves failed and UF{sub 6} was released. The remaining cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  18. Adjunction, Labeling, and Bare Phrase Structure

    Directory of Open Access Journals (Sweden)

    Norbert Hornstein

    2008-03-01

    Full Text Available The primary aim in this paper is to propose a phrase structure for adjunction that is compatible with the precepts of Bare Phrase Structure (BPS. Current accounts are at odds with the central vision of BPS and current practice leans more to descriptive eclecticism than to theoretical insight. A diagnosis for this conceptual disarray is suggested here: It stems from a deeply held though seldom formulated intuition; the tacit view that adjuncts are the abnormal case while arguments describe the grammatical norm. In actuality, it is argued, adjuncts are so well behaved that they require virtually no grammatical support to function properly. Arguments, in contrast, are refractory and require grammatical aid to allow them to make any propositional contribution. This last remark should come as no surprise to those with neo-Davidsonian semantic sympathies. Connoisseurs of this art form are well versed in the important role that grammatical (aka, thematic roles play in turning arguments into modifiers of events. Such fulcra are not required for meaningfully integrating adjuncts. into sentences. In what follows, we take this difference to be of the greatest significance and we ask ourselves what this might imply for the phrase structure of adjunction.

  19. Room temperature synthesis of ultra-small, near-unity single-sized lead halide perovskite quantum dots with wide color emission tunability, high color purity and high brightness

    Science.gov (United States)

    Peng, Lucheng; Geng, Jing; Ai, Lisha; Zhang, Ying; Xie, Renguo; Yang, Wensheng

    2016-08-01

    Phosphor with extremely narrow emission line widths, high brightness, and wide color emission tunability in visible regions is required for display and lighting applications, yet none has been reported in the literature so far. In the present study, single-sized lead halide perovskite (APbX 3; A = CH3NH3 and Cs; X = Cl, Br, and I) nanocrystalline (NC) phosphors were achieved for the first time in a one-pot reaction at room temperature (25 °C). The size-dependent samples, which included four families of CsPbBr3 NCs and exhibited sharp excitonic absorption peaks and pure band gap emission, were directly obtained by simply varying the concentration of ligands. The continuity of the optical spectrum can be successively tuned over the entire UV-visible spectral region (360-610 nm) by preparing CsPbCl3, CsPbI3, and CsPb(Y/Br)3 (Y = Cl and I) NCs with the use of CsPbBr3 NCs as templates by anion exchange while maintaining the size of NCs and high quantum yields of up to 80%. Notably, an emission line width of 10-24 nm, which is completely consistent with that of their single particles, indicates the formation of single-sized NCs. The versatility of the synthetic strategy was validated by extending it to the synthesis of single-sized CH3NH3PbX 3 NCs by simply replacing the cesium precursor by the CH3NH3 X precursor.

  20. Elastic and inclusive proton--proton scattering with bare-Pomeron intercept above 1

    International Nuclear Information System (INIS)

    Chu, S.; Desai, B.R.; Shen, B.C.; Field, R.D.

    1976-01-01

    An analysis of high-energy proton--proton scattering with bare-Pomeron intercept above 1 is presented. By use of a value α/sub P/(0) = 1.06, determined by the energy dependence of the pp total cross section, a triple-Regge analysis of the inclusive process pp → pX is carried out and compared with the results of a more conventional analysis with α/sub P/(0) = 1. The resulting triple-Regge couplings are used in calculating the second-order corrections to the bare Pomeron in the bare perturbation expansion of Reggeon field theory. We find that such an approach can correctly describe the existing high-energy pp total cross-section, elastic-, and inclusive-scattering data

  1. v-bare and the Sudbury Neutrino Observatory

    International Nuclear Information System (INIS)

    Orrell, J.L.

    2004-01-01

    Neutrino oscillation results from KamLAND, the Sudbury Neutrino Observatory (SNO), and Super-Kamiokande provide evidence for neutrino mass. Determination of the Dirac or Majorana nature of neutrinos is an important next step in neutrino physics. An electron antineutrino, v-bare, component of the solar neutrino flux would provide a telltale sign neutrinos are Majorana particles. The SNO Collaboration is currently searching for an v-bare signal, intending to measure or limit the flux of v-bare in the solar neutrino energy range. A method for increasing the fiducial volume and lowering the analysis energy threshold using the time coincidence signature of the product particles of the charged current weak interaction of a v-bare with a deuterium nucleus, v-bare + d → e+ + n + n, is presented

  2. Bare Fiber Bragg Gratings embedded into concrete buffer Supercontainer concept for nuclear waste storage

    International Nuclear Information System (INIS)

    Kinet, Damien; Chah, Karima; Megret, Patrice; Caucheteur, Christophe; Gusarov, Andrei; Faustov, Alexey; Areias, Lou

    2015-01-01

    We present the preliminary results obtained with bare fiber Bragg grating-based sensors embedded into half-scale Belgian Supercontainer concept. Being temperature and strain sensitive, some sensors were placed into aluminum tubes to monitor only temperature and results were compared with thermocouples data. The utility of using bare fiber Bragg gratings, knowing that these ones are very fragile, is to have a direct contact between the high alkaline environment of the concrete and silica fibers and to determine its impact over a very long time. (authors)

  3. Bare Fiber Bragg Gratings embedded into concrete buffer Supercontainer concept for nuclear waste storage

    Energy Technology Data Exchange (ETDEWEB)

    Kinet, Damien; Chah, Karima; Megret, Patrice; Caucheteur, Christophe [Electromagnetism and Telecommunications Department of the University of Mons, 31 Boulevard Dolez, 7000 Mons, (Belgium); Gusarov, Andrei [Belgian Nuclear Research Center, Boeretang 200, 2400 Mol, (Belgium); Faustov, Alexey [Belgian Nuclear Research Center, Boeretang 200, 2400 Mol, (Belgium); Electromagnetisme and Telecommunication Department of the University of Mons, 31 Boulevard Dolez, 7000 Mons, (Belgium); Areias, Lou [Mechanics of Materials and Constructions Department of the Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, (Belgium); European Underground Research Infrastructure for Disposal of nuclear waste In Clay Environment, Boeretang 200, 2400 Mol, (Belgium)

    2015-07-01

    We present the preliminary results obtained with bare fiber Bragg grating-based sensors embedded into half-scale Belgian Supercontainer concept. Being temperature and strain sensitive, some sensors were placed into aluminum tubes to monitor only temperature and results were compared with thermocouples data. The utility of using bare fiber Bragg gratings, knowing that these ones are very fragile, is to have a direct contact between the high alkaline environment of the concrete and silica fibers and to determine its impact over a very long time. (authors)

  4. Corrosion of bare and galvanized steel in gypsum

    Directory of Open Access Journals (Sweden)

    Gómez, Mercedes

    1988-12-01

    Full Text Available Gypsum is a relatively low-cost building material much abounding in our country. When it is put in contact with steel, it may produce high corrosion rates due to its pH value (close to 7. This work reports the results obtained in studying the corrosion rates of bare and galvanized steel in contact with gypsum and plaster, as well as the influence curing thermal treatment applied to gypsum, enviromental relative humidity and addition of compounds with different natures and purposes may have in such process. In-situ observations, as well as the measurement of the Polarization Resistance and the weight loss have been used as measurement technics. From the results obtained it has been possible to deduce that galvanized steel has better behaviour in dry enviroments than bare steel in the same conditions and moist atmosphere induces proportionally more corrosion in galvanized steel than in bare one. Additions to gypsum do not modified these conclusions, though it may be pointed out that addition of nitrites or lime improves the behaviour of bare steel, while galvanized behaviour is not modified. The addition of lime is not recommended because phenomena of dilated along time expansion may take place.

    El yeso es un material de construcción de relativo bajo coste y que, además, es muy abundante en nuestro país. Debido a su pH cercano a la neutralidad, cuando entra en contacto con el acero, este puede corroerse a elevadas velocidades. En esta comunicación se presentan los resultados de un estudio sobre la velocidad de corrosión del acero desnudo y galvanizado en contacto con yeso y escayola y la influencia que tienen: el tratamiento térmico del curado del yeso, la humedad relativa ambiental y la adición de aditivos de diversa naturaleza y finalidad. Como técnicas de medida se han utilizado la medida de la Resistencia de Polarización y de la pérdida de peso, así como observaciones visuales. De los resultados se puede deducir que en

  5. Fashion Brand Purity and Firm Performance

    Directory of Open Access Journals (Sweden)

    Jin-hui Zheng

    2013-01-01

    Full Text Available A large number of prior empirical research and case studies used qualitative methodology to discuss the fashion brand dilution resulting from consumer base extension from the target group(s to the nontarget groups and its impacts. From a different perspective, this paper establishes a dynamic brand dilution and performance model, demonstrating how dynamic changes of sales volumes involving the two consumer groups affect the degree of brand dilution and the performance of the brand. We incorporate the factor “brand purity” to the model as a quantitative measure of brand dilution level that affects firm annual revenue and profit change comprehensively in iteration. Our model suggests that fashion brands, especially luxury brands, can be easily diluted under the pressure of firm growth, and the brands suffer the significant negative impact on their revenues and profit. While increasing sales volume can aggravate the negative consequences, brand purity can be increased through limiting the consumer base to the target group only.

  6. Actinium radioisotope products of enhanced purity

    Science.gov (United States)

    Meikrantz, David Herbert; Todd, Terry Allen; Tranter, Troy Joseph; Horwitz, E. Philip

    2010-06-15

    A product includes actinium-225 (.sup.225Ac) and less than about 1 microgram (.mu.g) of iron (Fe) per millicurie (mCi) of actinium-225. The product may have a radioisotopic purity of greater than about 99.99 atomic percent (at %) actinium-225 and daughter isotopes of actinium-225, and may be formed by a method that includes providing a radioisotope mixture solution comprising at least one of uranium-233 (.sup.233U) and thorium-229 (.sup.229Th), extracting the at least one of uranium-233 and thorium-229 into an organic phase, substantially continuously contacting the organic phase with an aqueous phase, substantially continuously extracting actinium-225 into the aqueous phase, and purifying the actinium-225 from the aqueous phase. In some embodiments, the product may include less than about 1 nanogram (ng) of iron per millicurie (mCi) of actinium-225, and may include less than about 1 microgram (.mu.g) each of magnesium (Mg), Chromium (Cr), and manganese (Mn) per millicurie (mCi) of actinium-225.

  7. Bare coupling constants and asymptotic behaviour in reggeon field theory

    International Nuclear Information System (INIS)

    Baig, M.

    1983-01-01

    A relation between the values of bare coupling constants and the asymptotic behaviour of the reggeon field theory (RFT) is discussed. It is shown how the numerical values of bare coupling constants fix the starting point of renormalization group trajectories which, in turn, determine the asymptotic behaviour of the RFT. Applications to a pure pomeron theory and a pomeron plus f-pole model are discussed. Some nontrivial phenomenological information concerning the values of bare triple-Regge pomeron-f-pole coupling constants is obtained

  8. Resolving the anomaly of bare habitable ground in Daisyworld

    Science.gov (United States)

    Hankin, Robin K. S.; Mitchell, Neil

    2011-02-01

    The parable of Daisyworld places biological homeostasis on a non-teleological basis. However, one feature of Daisyworld is that, at equilibrium, the system appears to require habitable but bare ground. The presence of bare ground is an unavoidable consequence of the death rate parameter γ. Here, we simplify Watson and Lovelock's original formulation by removing γ and allowing instead the black and white daisies to infiltrate each others' territory. This device furnishes a model in which the area of bare ground asymptotically approaches zero. The infiltration process is modelled in terms of a parameter that is ecologically interpretable as a quantification of the incumbent advantage enjoyed by the dominant species.

  9. Isolation and Purity Assessment of Membranes from Norway Spruce.

    Science.gov (United States)

    Väisänen, Enni; Takahashi, Junko; Jiménez Barboza, Luis A; Deng, Xianbao; Teeri, Teemu H; Fagerstedt, Kurt V; Lüthje, Sabine; Kärkönen, Anna

    2018-01-01

    Gaining membrane vesicles from different plant species and tissue types is crucial for membrane studies. Membrane vesicles can be used for further purification of individual membrane types, and, for example, in studies of membrane enzyme activities, transport assays, and in proteomic analysis. Membrane isolation from some species, such as conifers, has proved to be more difficult than that of angiosperm species. In this paper, we describe steps for isolating cellular membranes from developing xylem, phloem, and lignin-forming tissue-cultured cells of Norway spruce, followed by partial enrichment of plasma membranes by aqueous polymer two-phase partitioning and purity analyses. The methods used are partially similar to the ones used for mono- and dicotyledonous plants, but some steps require discreet optimization, probably due to a high content of phenolic compounds present in the tissues and cultured cells of Norway spruce.

  10. Survey of the preparation, purity, and availability of silanes

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, J.H.

    1983-12-01

    Silane and disilane are currently available as prepared for the semiconductor market. Published or public information on preparative methods for monosilane and higher silanes are discussed. Purification techniques are reviewed. Data from current silane suppliers are tabulated. A short review of the silanes in Japan is given. Analytical procedures are not now perfected to determine group 3 or 5 elements in silane. All commercial silanes contain certain impurities. There is no simple one step purification technique for silane which a user could easily operate. Typical and actual analyses of commercial silane are given. Disilane is still in the development stage with only small quantities available at very high prices. The silane process developed in part under the DOE/JPL Flat Plate Solar Array project by Union Carbide is summarized. Higher purity silanes are now appearing on the market. These should be useful in the photovoltaic area.

  11. 10 CFR 36.63 - Pool water purity.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Pool water purity. 36.63 Section 36.63 Energy NUCLEAR... § 36.63 Pool water purity. (a) Pool water purification system must be run sufficiently to maintain the conductivity of the pool water below 20 microsiemens per centimeter under normal circumstances. If pool water...

  12. Household and meals versus the Temple purity system: Patterns of ...

    African Journals Online (AJOL)

    In this study the thesis is advanced that in contrast to the Temple and the exclusivist purity and legal system it represents, Luke has used occasions of domestic dining and hospitality to depict an inclusive form of social relations which transcends previous Jewish purity regulations and which gives concrete social expression ...

  13. Testing culture purity in prokaryotes: criteria and challenges.

    Science.gov (United States)

    Pinevich, Alexander V; Andronov, Eugeny E; Pershina, Elizaveta V; Pinevich, Agnia A; Dmitrieva, Helena Y

    2018-02-27

    Reliance on pure cultures was introduced at the beginning of microbiology as a discipline and has remained significant although their adaptive properties are essentially dissimilar from those of mixed cultures and environmental populations. They are needed for (i) taxonomic identification; (ii) diagnostics of pathogens; (iii) virulence and pathogenicity studies; (iv) elucidation of metabolic properties; (v) testing sensitivity to antibiotics; (vi) full-length genome assembly; (vii) strain deposition in microbial collections; and (viii) description of new species with name validation. Depending on the specific task there are alternative claims for culture purity, i.e., when conventional criteria are satisfied or when looking deeper is necessary. Conventional proof (microscopic and plating controls) has a low resolution and depends on the observer's personal judgement. Phenotypic criteria alone cannot prove culture purity and should be complemented with genomic criteria. We consider the possible use of DNA high-throughput culture sequencing data to define criteria for only one genospecies, axenic state detection panel and only one genome. The second and third of these are preferable, although their resolving capacity (depth) is limited. Because minor contaminants may go undetected, even with deep sequencing, the reliably pure culture would be a clonal culture launched from a single cell or trichome (multicellular bacterium). Although this type of culture is associated with technical difficulties and cannot be employed on a large scale (the corresponding inoculums may have low chances of growth when transferred to solid media), it is hoped that the high-throughput culturing methods introduced by 'culturomics' will overcome this obstacle.

  14. Purity and crystallinity of microwave synthesized antimony sulfide microrods

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Alonso, Claudia, E-mail: claudiamartinezalonso30@gmail.com [Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, Querétaro, 76010 (Mexico); Olivos-Peralta, Eliot U. [Instituto de Energías Renovables, Universidad NacionalAutónoma de México, Temixco, Morelos, 62580 (Mexico); Sotelo-Lerma, Mérida [Universidad de Sonora, Hermosillo, Sonora, 83000 (Mexico); Sato-Berrú, Roberto Y. [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, MéxicoD.F., 04510 (Mexico); Mayén-Hernández, S.A. [Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, Querétaro, 76010 (Mexico); Hu, Hailin, E-mail: hzh@ier.unam.mx [Instituto de Energías Renovables, Universidad NacionalAutónoma de México, Temixco, Morelos, 62580 (Mexico)

    2017-01-15

    Antimony sulfide (Sb{sub 2}S{sub 3}) is a promising semiconductor material for solar cell applications. In this work, microrods of Sb{sub 2}S{sub 3} were synthesized by microwave heating with different sulfur sources, solvents, temperature, heating rate, power, and solution concentration. It was found that 90% of stoichiometric Sb{sub 2}S{sub 3} can be obtained with thiourea (TU) or thioacetamide (TA) as sulfur sources and that their optical band gap values were within the range of 1.59–1.60 eV. The most crystalline Sb{sub 2}S{sub 3} were obtained by using TU. The morphology of the Sb{sub 2}S{sub 3} with TU the individual rods were exhibited, whereas rods bundles appeared in TA-based products. The solvents were ethylene glycol (EG) and dimethylformamide (DMF). EG generates more heat than DMF during the microwave synthesis. As a result, the Sb{sub 2}S{sub 3} obtained with EG contained a larger percentage of oxygen and smaller crystal sizes compared to those from DMF. On the other hand, the length and diameter of Sb{sub 2}S{sub 3} microrods can be increased by applying higher heating power although the crystal size did not change at all. In summary, pure and highly crystalline Sb{sub 2}S{sub 3} microrods of 6–10 μm long and 330–850 nm in diameter can be obtained by the microwave method with a careful selection of chemical and thermodynamic parameters of the synthesis. - Highlights: • Purity up to 90% of crystalline Sb{sub 2}S{sub 3} nanorods can be obtained by microwave heating. • The combination of solvent and sulfide type affects crystallinity & purity of Sb2S3. • The high pressure generated in microwave heating helps to form Sb{sub 2}S{sub 3} nanorods.

  15. Genetics Home Reference: bare lymphocyte syndrome type II

    Science.gov (United States)

    ... Immunodeficiency Disorders Health Topic: Immune System and Disorders Genetic and Rare Diseases Information Center (1 link) Bare lymphocyte syndrome 2 Additional NIH Resources (1 link) National Institute of Allergy and Infectious Diseases: Primary Immune Deficiency Diseases Educational Resources (6 ...

  16. Bare and effective fluid description in brane world cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Norman [Universidad de Santiago, Departamento de Fisica, Facultad de Ciencia, Casilla 307, Santiago (Chile); Lepe, Samuel; Saavedra, Joel [Pontificia Universidad Catolica de Valparaiso, Instituto de Fisica, Casilla 4950, Valparaiso (Chile); Pena, Francisco [Universidad de La Frontera, Departamento de Ciencias Fisicas, Facultad de Ingenieria, Ciencias y Administracion, Avda. Francisco Salazar 01145, Casilla 54-D, Temuco (Chile)

    2010-03-15

    An effective fluid description, for a brane world model in five dimensions, is discussed for both signs of the brane tension. We found several cosmological scenarios where the effective equation differs widely from the bare equation of state. For universes with negative brane tension, with a bare fluid satisfying the strong energy condition, the effective fluid can cross the barrier {omega} {sub eff}=-1. (orig.)

  17. Native bare zone assemblage nucleates myosin filament assembly.

    Science.gov (United States)

    Niederman, R; Peters, L K

    1982-11-15

    Native myosin filaments from rabbit psoas muscle are always 1.5 micrometer long. The regulated assembly of these filaments is generally considered to occur by an initial antiparallel and subsequent parallel aggregation of identical myosin subunits. In this schema myosin filament length is controlled by either a self-assembly or a Vernier process. We present evidence which refines these ideas. Namely, that the intact myosin bare zone assemblage nucleates myosin filament assembly. This suggestion is based on the following experimental evidence. (1) A native bare zone assemblage about 0.3 micrometer long can be formed by dialysis of native myosin filaments to either a pH 8 or a 0.2 M-KCl solution. (2) Upon dialysis back to 0.1 M-KCl, bare zone assemblages and distal myosin molecules recombine to form 1.5 micrometer long bipolar filaments. (3) The bare zone assemblage can be separated from the distal myosin molecules by column chromatography in 0.2 M-KCl. Upon dialysis of the fractionated subsets back to 0.1 M-KCl, the bare zone assemblage retains its length of about 0.3 micrometer. However, the distal molecules reassemble to form filaments about 5 micrometers long. (4) Filaments are formed from mixes of the isolated subsets. The lengths of these filaments vary with the amount of distal myosin present. (5) When native filaments, isolated bare zone assemblages or distal myosin molecules are moved sequentially to 0.6 M-KCl and then to 0.1 M-KCl, the final filament lengths are all about 5 micrometers. The capacity of the bare zone assemblage to nucleate filament assembly may be due to the bare zone myosin molecules, the associated M band components or both.

  18. Simplified method for determining radiochemical purity of 99mTc-TRODAT-1

    International Nuclear Information System (INIS)

    Chen, Z.P.; Wang, S.P.; Tang, J.; Li, X.M.; Liu, C.Y.; Xu, X.J.; Cao, G.X.

    2008-01-01

    To provide a convenient and facile method to evaluate the radiochemical purity (RCP) of 99m Tc-TRODAT-1 in quality control of routine clinical application, a simplified method of single-strip thin layer chromatography (TLC) was developed and validated by high performance liquid chromatography (HPLC). The RCP data of TLC correlated well with HPLC. (author)

  19. EAARL Coastal Topography-Chandeleur Islands, Louisiana, 2010: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Bonisteel-Cormier, Jamie M.; Brock, John C.; Sallenger, A.H.; Wright, C. Wayne; Nagle, David B.; Vivekanandan, Saisudha; Yates, Xan; Klipp, Emily S.

    2010-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived bare-earth (BE) and submerged topography datasets were produced collaboratively by the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Chandeleur Islands, acquired March 3, 2010. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color-infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom

  20. EAARL Coastal Topography - Northern Gulf of Mexico, 2007: Bare Earth

    Science.gov (United States)

    Smith, Kathryn E.L.; Nayegandhi, Amar; Wright, C. Wayne; Bonisteel, Jamie M.; Brock, John C.

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. The purpose of this project is to provide highly detailed and accurate datasets of select barrier islands and peninsular regions of Louisiana, Mississippi, Alabama, and Florida, acquired on June 27-30, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using

  1. EAARL Coastal Topography-Pearl River Delta 2008: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Miner, Michael D.; Yates, Xan; Bonisteel, Jamie M.

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the University of New Orleans (UNO), Pontchartrain Institute for Environmental Sciences (PIES), New Orleans, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Pearl River Delta in Louisiana and Mississippi, acquired March 9-11, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the

  2. ORSPHERE: CRITICAL, BARE, HEU(93.2)-METAL SPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Margaret A. Marshall

    2013-09-01

    In the early 1970’s Dr. John T. Mihalczo (team leader), J.J. Lynn, and J.R. Taylor performed experiments at the Oak Ridge Critical Experiments Facility (ORCEF) with highly enriched uranium (HEU) metal (called Oak Ridge Alloy or ORALLOY) in an attempt to recreate GODIVA I results with greater accuracy than those performed at Los Alamos National Laboratory in the 1950’s (HEU-MET-FAST-001). The purpose of the Oak Ridge ORALLOY Sphere (ORSphere) experiments was to estimate the unreflected and unmoderated critical mass of an idealized sphere of uranium metal corrected to a density, purity, and enrichment such that it could be compared with the GODIVA I experiments. “The very accurate description of this sphere, as assembled, establishes it as an ideal benchmark for calculational methods and cross-section data files.” (Reference 1) While performing the ORSphere experiments care was taken to accurately document component dimensions (±0. 0001 in. for non-spherical parts), masses (±0.01 g), and material data The experiment was also set up to minimize the amount of structural material in the sphere proximity. A three part sphere was initially assembled with an average radius of 3.4665 in. and was then machined down to an average radius of 3.4420 in. (3.4425 in. nominal). These two spherical configurations were evaluated and judged to be acceptable benchmark experiments; however, the two experiments are highly correlated.

  3. Computational approach to quantum encoder design for purity optimization

    International Nuclear Information System (INIS)

    Yamamoto, Naoki; Fazel, Maryam

    2007-01-01

    In this paper, we address the problem of designing a quantum encoder that maximizes the minimum output purity of a given decohering channel, where the minimum is taken over all possible pure inputs. This problem is cast as a max-min optimization problem with a rank constraint on an appropriately defined matrix variable. The problem is computationally very hard because it is nonconvex with respect to both the objective function (output purity) and the rank constraint. Despite this difficulty, we provide a tractable computational algorithm that produces the exact optimal solution for codespace of dimension 2. Moreover, this algorithm is easily extended to cover the general class of codespaces, in which case the solution is suboptimal in the sense that the suboptimized output purity serves as a lower bound of the exact optimal purity. The algorithm consists of a sequence of semidefinite programmings and can be performed easily. Two typical quantum error channels are investigated to illustrate the effectiveness of our method

  4. Ionization of atoms by bare ion projectiles

    Energy Technology Data Exchange (ETDEWEB)

    Tribedi, L.C. [J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506-2604 (United States)

    1997-02-01

    The double differential cross sections (DDCS) for low energy electron emission can provide stringent tests to the theoretical models for ionization in ion-atom collision. The two-center effects and the post collision interactions play a major role in ionization by highly charged, high Z projectiles. We{close_quote}ll review the recent developments in this field and describe our efforts to study the energy and angular distributions of the low energy electrons emitted in ion-atom ionization. {copyright} {ital 1997 American Institute of Physics.}

  5. Effect of bare mass on the Hosotani mechanism

    International Nuclear Information System (INIS)

    Takenaga, Kazunori

    2003-01-01

    It is pointed out that the existence of bare mass terms for matter fields changes gauge symmetry patterns through the Hosotani mechanism. As a demonstration, we study an SU(2) gauge model with massive adjoint fermions defined on M 4 x S 1 . It turns out that the vacuum structure changes at certain critical values of mL, where m (L) stands for the bare mass (the circumference of S 1 ). The gauge symmetry breaking patterns are different from models with massless adjoint fermions. We also consider a supersymmmetric SU(2) gauge model with adjoint hypermultiplets, in which the supersymmetry is broken by bare mass terms for the gaugino and squark fields instead of the Scherk-Schwarz mechanism

  6. The effective delayed neutron fraction for bare-metal criticals

    International Nuclear Information System (INIS)

    Pearlstein, S.

    1999-01-01

    Given sufficient material, a large number of actinides could be used to form bare-metal criticals. The effective delayed neutron fraction for a bare critical comprised of a fissile material is comparable with the absolute delayed neutron fraction. The effective delayed neutron fraction for a bare critical composed of a fissionable material is reduced by factors of 2 to 10 when compared with the absolute delayed neutron fraction. When the effective delayed neutron fraction is small, the difference between delayed and prompt criticality is small, and extreme caution must be used in critical assemblies of these materials. This study uses an approximate but realistic model to survey the actinide region to compare effective delayed neutron fractions with absolute delayed neutron fractions

  7. Semantic coherence in English accusative-with-bare-infinitive constructions

    DEFF Research Database (Denmark)

    Jensen, Kim Ebensgaard

    2013-01-01

    Drawing on usage-based cognitively oriented construction grammar, this paper investigates the patterns of coattraction of items that appear in the two VP positions (the VP in the matrix clause, and the VP in the infinitive subordinate clause) in the English accusative-with-bare-infinitive constru......Drawing on usage-based cognitively oriented construction grammar, this paper investigates the patterns of coattraction of items that appear in the two VP positions (the VP in the matrix clause, and the VP in the infinitive subordinate clause) in the English accusative...... relations of English accusatives-with-bare-infinitives through the relations of semantic coherence between the two VPs....

  8. Model-based characterisation of growth performance and l-lactic acid production with high optical purity by thermophilic Bacillus coagulans in a lignin-supplemented mixed substrate medium.

    Science.gov (United States)

    Glaser, Robert; Venus, Joachim

    2017-07-25

    Three Bacillus coagulans strains were characterised in terms of their ability to grow in lignin-containing fermentation media and to consume the lignocellulose-related sugars glucose, xylose, and arabinose. An optical-density high-throughput screening was used for precharacterisation by means of different mathematical models for comparison (Logistic, Gompertz, Baranyi, Richards & Stannard, and Schnute). The growth response was characterised by the maximum growth rate and lag time. For a comparison of the screening and fermentation results, an unstructured mathematical model was proposed to characterise the lactate production, bacterial growth and substrate consumption. The growth model was then applied to fermentation procedures using wheat straw hydrolysates. The results indicated that the unstructured growth model can be used to evaluate lactate producing fermentation. Under the experimental fermentation conditions, one strain showed the ability to tolerate a high lignin concentration (2.5g/L) but lacked the capacity for sufficient pentose uptake. The lactate yield of the strains that were able to consume all sugar fractions of glucose, xylose and arabinose was ∼83.4%. A photometric measurement at 280nm revealed a dynamic change in alkali-lignin concentrations during lactate producing fermentation. A test of decolourisation of vanillin, ferulic acid, and alkali-lignin samples also showed the decolourisation performance of the B. coagulans strains under study. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  9. Eu2+-doped Ba2GaB4O9Cl blue-emitting phosphor with high color purity for near-UV-pumped white light-emitting diodes

    Science.gov (United States)

    Gao, Zhiwen; Deng, Huajuan; Xue, Na; Jeong, Jung Hyun; Yu, Ruijin

    2018-01-01

    Eu2+-doped borate fluoride Ba2GaB4O9Cl was synthesized by the conventional high-temperature solid-state reaction. The crystal structure and luminescence properties of the phosphors, as well as their thermal luminescence quenching capabilities and CIE chromaticity coordinates were systematically investigated. Under the excitation at 340 nm, the phosphor exhibited an asymmetric broad-band blue emission with a peak at 445 nm, which is ascribed to the 4f-5d transition of Eu2+. It was further proved that energy transfer among the nearest neighbor ions is the major mechanism for concentration quenching of Eu2+ in Ba2-xGaB4O9Cl:xEu2+ phosphors. The luminescence quenching temperature is 432 K. The CIE color coordinates are very close to those of BaMgAl10O17:Eu2+ (BAM). All the properties indicated that the blue-emitting Ba2GaB4O9Cl:Eu2+ phosphor has potential application in white LEDs.

  10. BARE retrotransposons are translated and replicated via distinct RNA pools.

    Directory of Open Access Journals (Sweden)

    Wei Chang

    Full Text Available The replication of Long Terminal Repeat (LTR retrotransposons, which can constitute over 80% of higher plant genomes, resembles that of retroviruses. A major question for retrotransposons and retroviruses is how the two conflicting roles of their transcripts, in translation and reverse transcription, are balanced. Here, we show that the BARE retrotransposon, despite its organization into just one open reading frame, produces three distinct classes of transcripts. One is capped, polyadenylated, and translated, but cannot be copied into cDNA. The second is not capped or polyadenylated, but is destined for packaging and ultimate reverse transcription. The third class is capped, polyadenylated, and spliced to favor production of a subgenomic RNA encoding only Gag, the protein forming virus-like particles. Moreover, the BARE2 subfamily, which cannot synthesize Gag and is parasitic on BARE1, does not produce the spliced sub-genomic RNA for translation but does make the replication competent transcripts, which are packaged into BARE1 particles. To our knowledge, this is first demonstration of distinct RNA pools for translation and transcription for any retrotransposon.

  11. Basic science of nuclear medicine the bare bone essentials

    CERN Document Server

    Lee, Kai H

    2015-01-01

    Through concise, straightforward explanations and supporting graphics that bring abstract concepts to life, the new Basic Science of Nuclear Medicine—the Bare Bone Essentials is an ideal tool for nuclear medicine technologist students and nuclear cardiology fellows looking for an introduction to the fundamentals of the physics and technologies of modern day nuclear medicine.

  12. Eelgrass beds and bare substrata – sparid and mugilid composition ...

    African Journals Online (AJOL)

    The results indicate that the family Mugilidae is better represented at unvegetated sites when compared to members of the family Sparidae, with the exception of Lithognathus lithognathus, but that the dominant three sparids and dominant two mugilids were most abundant in sparse eelgrass beds that included both bare ...

  13. Hydrodynamic behavior of a bare rod bundle. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Bartzis, J.G.; Todreas, N.E.

    1977-06-01

    The temperature distribution within the rod bundle of a nuclear reactor is of major importance in nuclear reactor design. However temperature information presupposes knowledge of the hydrodynamic behavior of the coolant which is the most difficult part of the problem due to complexity of the turbulence phenomena. In the present work a 2-equation turbulence model--a strong candidate for analyzing actual three dimensional turbulent flows--has been used to predict fully developed flow of infinite bare rod bundle of various aspect ratios (P/D). The model has been modified to take into account anisotropic effects of eddy viscosity. Secondary flow calculations have been also performed although the model seems to be too rough to predict the secondary flow correctly. Heat transfer calculations have been performed to confirm the importance of anisotropic viscosity in temperature predictions. All numerical calculations for flow and heat have been performed by two computer codes based on the TEACH code. Experimental measurements of the distribution of axial velocity, turbulent axial velocity, turbulent kinetic energy and radial Reynolds stresses were performed in the developing and fully developed regions. A 2-channel Laser Doppler Anemometer working on the Reference mode with forward scattering was used to perform the measurements in a simulated interior subchannel of a triangular rod array with P/D = 1.124. Comparisons between the analytical results and the results of this experiment as well as other experimental data in rod bundle array available in literature are presented. The predictions are in good agreement with the results for the high Reynolds numbers.

  14. Thermal strain measurement of EAST tungsten divertor component with bare fiber Bragg grating sensors

    Science.gov (United States)

    Wang, Xingli; Wang, Wanjing; Wang, Jichao; Wei, Ran; Sun, Zhaoxuan; Li, Qiang; Xie, Chunyi; Luo, Guang-Nan

    2017-12-01

    Fiber Bragg Gratings (FBGs) have been widely used in the sensor field to monitor temperature and strain. However, the weak mechanical property of optical fibers and insufficient heat-resistant property of general optic-fiber sensors have prevented it from being widely used, such as in some extreme engineering situations. In this work, a bare FBG sensor system had been introduced to measure thermal strain of an Experimental Advanced Superconducting Tokamak tungsten divertor component under baking condition. This strain measurement system had withstood as high temperature as 210 °C and finished the measurement experiment successfully. Meaningful measurement results had been obtained and analyzed, which showed the applicability of such a bare fiber grating sensor system and as well contributed to studying on tungsten divertor's thermal strain conditions.

  15. Ionization of excited hydrogen and excited hydrogen-like ions in collisions with bare ions

    International Nuclear Information System (INIS)

    Igarashi, Akinori; Shirai, Toshizo

    1995-01-01

    Accompanying the heightening of the density of nuclear fusion plasma and the heightening of the energy of incident atoms, attention has been paid to multi-stage collision excitation process. This collision process possesses a large cross section, and the evaluation of the cross section is an urgent task to analyze the efficiency of plasma heating. In this study, by using CDW-EIS approximation, of which the calculation is relatively easy, the ionization cross section in the collision of bare ions with excited state hydrogen and hydrogen-like ions was calculated. The CDW-EIS approximation was introduced by Crothers and McCann, and it is the high energy approximation that reproduces best the experimental data on the ionization cross section of ground state hydrogen by bare ions. It was confirmed by the result of make-up calculation that if energy becomes high to some extent, the CDW-EIS approximation and Born approximation approach and agree for the ionization from ground state and also from excited state. The results of the ionization collision of bare ions with excited hydrogen atoms and excited hydrogen-like ions are reported. (K.I.)

  16. CHELATING LIGANDS: ENHANCERS OF QUALITY AND PURITY ...

    African Journals Online (AJOL)

    Nwokem et al.

    ABSTRACT. The quality of biogas depends largely on the percentage of methane and hydrogen sulphide gas present. High concentration of hydrogen sulphide results in low quality biogas. This work employed the use of chelating ligands in scrubbing hydrogen sulphide gas while improving the yield of methane gas.

  17. Growth of high purity semiconductor epitaxial layers by liquid phase ...

    Indian Academy of Sciences (India)

    Unknown

    The gas lines are normally made of 316 stainless steel. Before installation, the inside of the tubes and valves are cleaned and passivated and (v) Pyrex or corning glass containers are used for cleaning the source materials and the substrate. These containers are, from time to time, treated with hot aqua regia and washed in.

  18. Analytical challenges in characterization of high purity materials

    Indian Academy of Sciences (India)

    Unknown

    analysis offers an impressive number of tools to simulta- neously determine a large number of elements and com- ..... introduction equipment. Magnetic sector multicollection detection systems with as many ..... able to fit around the curved focal region of other mass- spectrometer designs. Further, because each detector chip.

  19. Preparation of high-purity tellurium by the combination method

    International Nuclear Information System (INIS)

    Kogtev, P.M.; Khachishvili, V.I.; Mozdokeli, T.G.

    1978-01-01

    Vacuum distillation followed by condensation in hydrogen flow has been studied as a means of T-1 brand Te purification (particularly from Se). The distillation lasted for 4-5 hours at 530-550 deg C under residual pressure of 10 -3 Torr. A schematic of the apparatus for the purification is given. Condensation under hydrogen flow decreases the amount of impurities in Te; double condensation reduces the Se content by 2 orders of magnitude. The product obtained after vacuum distillation and double condensation under pure H sub(2) is 99.999 % Te

  20. Magnetophotoluminescence in high purity MOVPE GaAs

    Science.gov (United States)

    Zemon, S. A.; Norris, P. E.; Lambert, G.

    1986-09-01

    Magnetophotoluminescence (MPL) is shown to be useful for the identification of trace acceptor impurities in MOVPE GaAs. Using MPL a trace concentration of zinc acceptors was detected in a sample where the zinc transitions were obscured in zero magnetic field. Acceptor MPL was observed to be insensitive to V/III ratio for values between 17.3 and 54.4. Conduction-band-to-acceptor MPL spectral widths as small as 0.3 meV were found. Resolved Landau level transitions and the magnetic splitting of conduction-band-to-acceptor transitions were observed.

  1. Extractive process for preparing high purity magnesium chloride hexahydrate

    Directory of Open Access Journals (Sweden)

    Fezei Radouanne

    2012-01-01

    Full Text Available This paper refers a method for the preparation of magnesium chloride hexahydrate (bischofite from Sebkha el Melah of Zarzis Tunisian natural brine. It is a five-stage process essentially based on crystallization by isothermal evaporation and chemical precipitation. The two first steps were dedicated to the crystallization of sodium chloride and potassiummagnesium double salts, respectively. Then, the resulting liquor was desulfated using calcium chloride solution. After that another isothermal evaporation stage was implemented in order to eliminate potassium ions in the form of carnallite, KCl.MgCl2.6H2O. At the end of this step, the recovered solution primarily composed of magnesium and chloride ions was treated by dioxan in order to precipitate magnesium chloride as MgCl2.6H2O.C4H8O2. This compound dried at constant temperature of 100°C gave good quality magnesium chloride hexahydrate. Besides this salt, the various by-products obtained from the different treatment stages are also useful.

  2. High purity materials as targets for radioisotope production: Needs ...

    Indian Academy of Sciences (India)

    Unknown

    emission tomography (PET) using positron emitting radionuclides. In industry, radionuclides due to their greater detection sensitivity and the fact that they ... controlled by Food & Drug Controller of the state, De- partment of Health and Nuclear Regulatory Agencies of. Figure 1. Radioisotope uses in medicine. Figure 2.

  3. Analytical challenges in characterization of high purity materials

    Indian Academy of Sciences (India)

    Unknown

    K L RAMAKUMAR. Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India ... 2. Analytical challenges in spark source mass spectrometry (SSMS). 2.1 Determination of hydrogen. Despite some of its limitations, SSMS with conventional .... Inductively coupled plasma mass spectrometry. (ICPMS).

  4. Determination of the vacancy formation enthalpy for high purity Ni

    International Nuclear Information System (INIS)

    Lynn, K.G.; Snead, C.L. Jr.; Hurst, J.J.; Farrell, K.

    1979-01-01

    Positron-annihilation lifetime measurements have been made on Ni over a temperature range of 4.2 to 1700 K. We find a small change in the lifetime from 4.2 - 900 K indicating a very small thermal-expansion effect. A small precursor effect is observed before the onset of significant vacancy trapping. A monovacancy formation enthalpy of 1.54sub(+0.2)sup(-0.1) eV is extracted without taking divacancies into consideration in the analysis. No detrapping from mono-vacancies is observed even at the higher temperatures. The vacancy formation enthalpy extracted from the lifetime data is compared to values obtained by Doppler-broadening and angular-correlation techniques. (author)

  5. Determination of the vacancy formation enthalpy for high purity Ni

    International Nuclear Information System (INIS)

    Lynn, K.G.; Snead, C.L. Jr.; Hurst, J.J.; Farrell, K.

    1979-01-01

    Positron-annihilation lifetime measurements have been made on Ni over a temperature range of 4.2 to 1700 K. We find a small change in the lifetime from 4.2 to 900 K indicating a very small thermal-expansion effect. A small precursor effect is observed before the onset of significant vacancy trapping. A monovacancy formation enthalpy of 1.54/sub +0.2//sup -0.1/ eV is extracted without taking divacancies into consideration in the analysis. No detrapping from mono-vacancies is observed even at the higher temperatures. The vacancy formation enthalpy extracted from the lifetime data is compared to values obtained by Doppler-broadening and angular-correlation techniques

  6. Determination of contaminators in high purity lead oxide

    International Nuclear Information System (INIS)

    Bellavigna, H.J.; Farias de Funes, S.; Garavaglia, R.N.

    1990-01-01

    Litharge (PbO) is one of the raw materials used in glass fabrication for shielding and cathodic ray tubes employed in measurement instruments; some elements such as silver, chromium, arsenic, bismuth, etc. may confer to the mentioned glasses different unwanted tones which cause image distortion. Emission spectroscopy with photographic detection gives a quick, effective and economical alternative to determine these impurities. (Author) [es

  7. High purity materials as targets for radioisotope production: Needs ...

    Indian Academy of Sciences (India)

    Unknown

    radionuclides in suitable radiochemical form, its facile detection and elegant tracer concepts are responsible for their unprecedented use. Application of radioisotopes in medicine has given birth to a new branch, viz. nuclear medicine, wherein radioisotopes are used extensively in the diagnosis and treatment of variety of dis ...

  8. Surface Characterization for High Purity Fe-Cr Alloys

    OpenAIRE

    Iwai, H.; Oiwa, R.; Takaki, S.; Abiko, K.

    1995-01-01

    Fe-50mass%Cr was prepared in a cold crucible furnace with induction heating, then refined by floating-zone melting (FZM). The chemistries on the surface before and after FZM were compared by XPS measurement. C and O were observed on top surfaces both before and after as a hydrocarbon, carbonyl group and carboxyl group which are adsorbed chemical components. The other impurities were observed on the surface in both cases ; however, the number and level of impurities on the surface after FZM we...

  9. A Purity Monitoring System for the H1 Liquid Argon Calorimeter

    CERN Document Server

    Barrelet, E

    2002-01-01

    The ionization probes used for monitoring the liquid argon purity in the H1 calorimeter are described and results of their operation in tests at CERN and during the period 1992 to the end of 1998 at HERA are given. The high sensitivity of the charge measurements leads to refined charge collection models, and to the observation of a variation of the ionization yield of our electron sources with temperature.

  10. Study of important parameters on the irradiation of {sup 124}Xe, to improve the production of {sup 123}I with high purity using the Cyclone-30 cyclotron at IPEN-CNEN/SP; Estudo de parametros relevantes na irradiacao de {sup 124}Xe, visando a otimizacao na obtencao de {sup 123}I ultra puro no ciclotron Cyclone-30 do IPEN-CNEN/SP

    Energy Technology Data Exchange (ETDEWEB)

    Sumiya, Luiz Carlos do Amaral

    2006-07-01

    The development of diagnosis equipment and therapy procedures in nuclear medicine depends on the availability of commercial radioisotopes. IPEN is the most important institution that provides radioisotopes for national market. In order to achieve this function, IPEN had invested in the acquisition of a 30 MeV Cyclone-30 cyclotron to produce mainly {sup 18}F, {sup 67}Ga, {sup 201}Tl and {sup 123}I. The {sup 123}I production is the aim of the present work. With the {sup 123}I routine production data obtained by proton irradiation of Xe targets with an enrichment greater than 99.8%, it was possible to identify the important parameters that have direct influence on the production yield of high purity degree {sup 123}I. Even though the methodology for the commercial production of {sup 123}I, there are an scarcity of operational parameters data for this task. In this work the evaluated parameters were: {sup 124}Xe pressure, proton beam quality, irradiation time, operational temperature of the irradiation system under irradiation, waiting time to obtain {sup 123}I, temperature of washing solution and the impact of the internal Ni coating in the target. With the obtained results it was possible to modify the operational conditions for routine production and increasing the efficiency in about 30%. (author)

  11. Thermally treated bare gold nanoparticles for colorimetric sensing of copper ions

    International Nuclear Information System (INIS)

    Deng, Hao-Hua; Liu, Ai-Lin; Chen, Wei; Lin, Xin-Hua; Li, Guang-Wen; Xia, Xing-Hua

    2014-01-01

    We demonstrate a sensitive and rapid colorimetric assay for selective detection of copper ions based on the strong coordination between Cu(II) ions and the tetrahydroxyaurate anions [Au(OH)4]− on the surface of thermally treated bare gold nanoparticles (GNPs). The method for making the unmodified GNPs is simple and results in a nanomaterial with a highly specific response to Cu(II). The thermal treatment of the bare GNPs and the recognition of Cu(II) ions is accomplished in a single step within 5 min. The presence of Cu(II) causes the color to change from red to purple-blue. The limit of detection (LOD) is 0.04 μM of Cu(II) when using UV–vis spectrometry and rotating the absorbances at 650 and 515 nm, respectively. The method also is amenable to bare eye (visual) inspection and in this case has an LOD of 2.0 μM of Cu(II). (author)

  12. Assembling Bare Au Nanoparticles at Positively Charged Templates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenjie; Zhang, Honghu; Kuzmenko, Ivan; Mallapragada, Surya; Vaknin, David

    2016-05-26

    In-situ X-ray reflectivity (XRR) and grazing incidence X-ray small-angle scattering (GISAXS) reveal that unfunctionalized (bare) gold nanoparticles (AuNP) spontaneously adsorb to a cationic lipid template formed by a Langmuir monolayer of DPTAP (1,2-dihexadecanoyl-3-trimethylammonium-propane) at vapor/aqueous interfaces. Analysis of the XRR yields the electron density profile across the chargedinterfaces along the surface normal showing the AuNPs assemble with vertical thickness comparable to the particle size. The GISAXS analysis indicates that the adsorbed mono-particle layer exhibits shortrange in-plane correlations. By contrast, single-stranded DNA-functionalized AuNPs, while attracted to the positively charged surface (more efficiently with the addition of salt to the solution), display less in-plane regular packing compared to bare AuNPs.

  13. Current Collection Experiment of Bare Electrodynamic Tether Using Sounding Rocket

    Science.gov (United States)

    Yamagiwa, Yoshiki; Kanbe, Atsushi; Wakatsuki, Masaru; Tanaka, Kouji; Sumino, Makoto; Watanabe, Takeo; Sahara, Hironori; Fujii, Hironori A.

    Three innovative tether technologies, tape tether deployment, attitude control by tether robot, and current collection by bare tether, will be verified in the Tether Experiment (T-REx) by using JAXA's sounding rocket S-520 in 2010. In the experiments, the current collection experiment by bare tether is the first experiment in space in the world, and it is expected that this experiment not only will give the new knowledge in plasma physics but also will be very important for the understanding of the charging phenomenon of spaceship and the design of the electrodynamic tether system in the future. The detail and the state of preparation of the experiment are shown in this paper.

  14. Low cost bare-plate solar air collector

    Science.gov (United States)

    Maag, W. L.; Wenzler, C. J.; Rom, F. E.; Vanarsdale, D. R.

    1980-09-01

    A low cost, bare plate solar collector for preheating ambient air was developed. This type of solar heating system would be applicable for preheating ventilation air for public buildings or other commercial and industrial ventilation requirements. Two prototype collectors were designed, fabricated and installed into an instrumented test system. Tests were conducted for a period of five months. Results of the tests showed consistent operating efficiencies of 60 percent or greater with air preheat temperature uses up to 20 degrees for one of the prototypes. The economic analyses indicated that this type of solar system was economically viable. For the materials of construction and the type of fabrication and installation perceived, costs for the bare plate solar collector are attainable. Applications for preheating ventilation air for schools were evaluated and judged to be economically viable.

  15. Aluminum anode for aluminum-air battery - Part I: Influence of aluminum purity

    Science.gov (United States)

    Cho, Young-Joo; Park, In-Jun; Lee, Hyeok-Jae; Kim, Jung-Gu

    2015-03-01

    2N5 commercial grade aluminum (99.5% purity) leads to the lower aluminum-air battery performances than 4N high pure grade aluminum (99.99% purity) due to impurities itself and formed impurity complex layer which contained Fe, Si, Cu and others. The impurity complex layer of 2N5 grade Al declines the battery voltage on standby status. It also depletes discharge current and battery efficiency at 1.0 V which is general operating voltage of aluminum-air battery. However, the impurity complex layer of 2N5 grade Al is dissolved with decreasing discharge voltage to 0.8 V. This phenomenon leads to improvement of discharge current density and battery efficiency by reducing self-corrosion reaction. This study demonstrates the possibility of use of 2N5 grade Al which is cheaper than 4N grade Al as the anode for aluminum-air battery.

  16. Isotopic Abundance and Chemical Purity Analysis of Stable Isotope Deuterium Labeled Sudan I

    Directory of Open Access Journals (Sweden)

    CAI Yin-ping;LEI Wen;ZHENG Bo;DU Xiao-ning

    2014-02-01

    Full Text Available It is important that to analysis of the isotopic abundance and chemical purity of Sudan I-D5, which is the internal standard of isotope dilution mass spectrometry. The isotopic abundance of Sudan I-D5 is detected by “mass cluster” classification method and LC-MS. The repeatability and reproducibility experiments were carried out by using different mass spectrometers and different operators. The RSD was less than 0.1%, so the repeatability and reproducibility were satisfactory. The accuracy and precision of the isotopic abundance analysis method was good with the results of F test and t test. The high performance liquid chromatography (HPLC had been used for detecting the chemical purity of Sudan I-D5 as external standard method.

  17. Bare lymphocyte syndrome: imaging findings in an adult

    Energy Technology Data Exchange (ETDEWEB)

    Bernaerts, A.; Vandevenne, J.E.; De Schepper, A.M. [Dept. of Radiology, Universitair Ziekenhuis Antwerpen, Edegem (Belgium); Lambert, J. [Dept. of Dermatology, Universitair Ziekenhuis Antwerpen, Edegem (Belgium); De Clerck, L.S. [Dept. of Immunology, Universitair Ziekenhuis Antwerpen, Edegem (Belgium)

    2001-05-01

    Bare lymphocyte syndrome (BLS) is a rare primary immune disorder characterized by defective expression of human leukocyte antigen (HLA) on lymphocytes, often resulting in extensive and recurrent multi-organ infections. We describe a previously undiagnosed case of an adult woman who presented with radiological findings of severe bronchiectases, near-total granulomatous destruction of facial bones, and osteomyelitis. Diagnosis of BLS should be considered when evaluating children with unexplained bronchiectases or adults with long history of chronic multi-organ infections. (orig.)

  18. Determination of the radiochemical purity of 51Cr-EDTA

    International Nuclear Information System (INIS)

    Toledo e Souza, I.T. de; Pereira, N.P.S. de.

    1987-08-01

    The miniature chromatography systems were elaborated to determine the radiochemical purity chromium 51 Cr-EDTA. Chromatography results using four different solvents were obtained and studied. 33% W/V aqueous solution of ammonium sulfate pH 7.5 gives the best chemical separation was concluded. (Author) [pt

  19. Capillary electrophoresis-based assessment of nanobody affinity and purity

    NARCIS (Netherlands)

    Haselberg, Rob; Oliveira, Sabrina; van der Meel, Roy; Somsen, Govert W; de Jong, Gerhardus J

    2014-01-01

    Drug purity and affinity are essential attributes during development and production of therapeutic proteins. In this work, capillary electrophoresis (CE) was used to determine both the affinity and composition of the biotechnologically produced "nanobody" EGa1, the binding fragment of a

  20. Bare-Hand Volume Cracker for Raw Volume Data Analysis

    Directory of Open Access Journals (Sweden)

    Bireswar Laha

    2016-09-01

    Full Text Available Analysis of raw volume data generated from different scanning technologies faces a variety of challenges, related to search, pattern recognition, spatial understanding, quantitative estimation, and shape description. In a previous study, we found that the Volume Cracker (VC 3D interaction (3DI technique mitigated some of these problems, but this result was from a tethered glove-based system with users analyzing simulated data. Here, we redesigned the VC by using untethered bare-hand interaction with real volume datasets, with a broader aim of adoption of this technique in research labs. We developed symmetric and asymmetric interfaces for the Bare-Hand Volume Cracker (BHVC through design iterations with a biomechanics scientist. We evaluated our asymmetric BHVC technique against standard 2D and widely used 3D interaction techniques with experts analyzing scanned beetle datasets. We found that our BHVC design significantly outperformed the other two techniques. This study contributes a practical 3DI design for scientists, documents lessons learned while redesigning for bare-hand trackers, and provides evidence suggesting that 3D interaction could improve volume data analysis for a variety of visual analysis tasks. Our contribution is in the realm of 3D user interfaces tightly integrated with visualization, for improving the effectiveness of visual analysis of volume datasets. Based on our experience, we also provide some insights into hardware-agnostic principles for design of effective interaction techniques.

  1. Group-based discrimination in judgments of moral purity-related behaviors: experimental and archival evidence.

    Science.gov (United States)

    Masicampo, E J; Barth, Maria; Ambady, Nalini

    2014-12-01

    Knowledge of individuals' group membership can alter moral judgments of their behavior. We found that such moral judgments were amplified when judgers learned that a person belonged to a group shown to elicit disgust in others. When a person was labeled as obese, a hippie, or "trailer trash," people judged that person's behavior differently than when such descriptors were omitted: Virtuous behaviors were more highly praised, and moral violations were more severely criticized. Such group-based discrimination in moral judgment was specific to the domain of moral purity. Members of disgust-eliciting groups but not members of other minorities were the target of harsh judgments for purity violations (e.g., lewd behavior) but not for other violations (e.g., refusing to help others). The same pattern held true for virtuous behaviors, so that members of disgust-eliciting groups were more highly praised than others but only in the purity domain. Furthermore, group-based discrimination was mediated by feelings of disgust toward the target group but not by other emotions. Last, analysis of New York Police Department officers' encounters with suspected criminals revealed a similar pattern to that found in laboratory experiments. Police officers were increasingly likely to make an arrest or issue a summons as body mass index increased (i.e., as obesity rose) among people suspected of purity crimes (e.g., prostitution) but not of other crimes (e.g., burglary). Thus, moral judgments in the lab and in the real world exhibit patterns of discrimination that are both group and behavior specific. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  2. Capillary gel electrophoresis for the quantification and purity determination of recombinant proteins in inclusion bodies.

    Science.gov (United States)

    Espinosa-de la Garza, Carlos E; Perdomo-Abúndez, Francisco C; Campos-García, Víctor R; Pérez, Néstor O; Flores-Ortiz, Luis F; Medina-Rivero, Emilio

    2013-09-01

    In this work, a high-resolution CGE method for quantification and purity determination of recombinant proteins was developed, involving a single-component inclusion bodies (IBs) solubilization solution. Different recombinant proteins expressed as IBs were used to show method capabilities, using recombinant interferon-β 1b as the model protein for method validation. Method linearity was verified in the range from 0.05 to 0.40 mg/mL and a determination coefficient (r(2) ) of 0.99 was obtained. The LOQs and LODs were 0.018 and 0.006 mg/mL, respectively. RSD for protein content repeatability test was 2.29%. In addition, RSD for protein purity repeatability test was 4.24%. Method accuracy was higher than 90%. Specificity was confirmed, as the method was able to separate recombinant interferon-β 1b monomer from other aggregates and impurities. Sample content and purity was demonstrated to be stable for up to 48 h. Overall, this method is suitable for the analysis of recombinant proteins in IBs according to the attributes established on the International Conference for Harmonization guidelines. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Increased recovery and improved purity of PHA from recombinant Cupriavidus necator.

    Science.gov (United States)

    Anis, Siti Nor Syairah; Iqbal, Nurhezreen Md; Kumar, Sudesh; Al-Ashraf, Amirul

    2013-01-01

    A simple procedure for recovering biodegradable polymer from bacterial cells has been developed using economical and environmentally friendly solvent or chemicals. Recombinant bacterium, Cupriavidus necator harboring pBBR1MCS-C2 plasmid polyhydroxyalkanoate (PHA) synthase gene was used for the production of copolymer P(3HB-co-3HHx) from crude palm kernel oil (CPKO). NaOH was chosen in this study as it could give high purity and recovery yield. Increase of NaOH concentration had resulted in an increase of the PHA purity, but the recovery yield had decreased. The greater improvement of PHA purity and recovery were achieved by incubating the freeze-dried cells (10-30 g/L) in NaOH (0.1 M) for 1-3 h at 30°C and polishing using 20% (v/v) of ethanol. The treatment caused negligible degradation of the molecular weight of PHA recovered from the bacterial cells. The present review also highlights other extraction methods to provide greater insights into economical and sustainable recovery of PHA from bacterial cells.

  4. [Maize Hybrid Seed Purity Identification Based on Near Infrared Reflectance (NIR) and Transmittance (NIT) Spectra].

    Science.gov (United States)

    Li, Tian-xin; Jia, Shi-qiang; Liu, Xu; Zhao, Sheng-yi; Ran, Hang; Yan, Yan-lu; An, Dong

    2015-12-01

    This article explore the feasibility of using Near Infrared Reflectance (NIR) and Transmittance (NIT) Spectroscopy (908.1-1677.2 nm wavelength range) to identify maize hybrid purity, and compare the performance of NIR and NIT spectroscopy. Principle Component Analysis (PCA) and Orthogonal Linear Discriminant Analysis (OLDA) were used to reduce the dimension of spectra which have been pretreated by first derivative and vector normalization. The hybrid purity identification model of Nonghua101 and Jingyu16 were built by SVM. Models based on NIR spectra obtained correct identification rate as 100% and 90% for Nonghua101 and Jingyu16 respectively. But NIR spectra were greatly influenced by the placement of seeds, and there existed significant difference between NIR spectra of embryo and non-embryo side. Models based on NIT spectroscopy yielded correct identification rate as 98% both for Nonghua101 and Jingyu16. NIT spectra of embryo and non-embryo side were highly similar. The results indicate that it is feasible to identify maize hybrid purity based on NIR and NIT spectroscopy, and NIT spectroscopy is more suitable to analyze single seed kernel than NIR spectroscopy.

  5. Purity determination and uncertainty evaluation of folic acid by mass balance method.

    Science.gov (United States)

    Gong, Hui; Huang, Ting; Yang, Yi; Wang, Haifeng

    2012-11-15

    Folic acid is one of the most important nutrient substances for human beings, especially for the pregnant women and infants. Therefore the purity determination of folic acid is particularly important. The mass balance method was employed to determine the purity of folic acid, by using the measures of high performance liquid chromatography (HPLC), Karl Fischer titration and other conventional approach. The moisture quantification of folic acid was a major problem since it is a thermally unstable substance and it is apt to contain crystal water. Therefore, a novel improved Karl Fischer method was established for accurate determination of the water content in folic acid, whose repeatability (RSD=2.9%) was significantly better than that of the original direct injection method (RSD=12%). The purity of folic acid certified reference material (CRM) determined by mass balance method was 90.9% with an expanded uncertainty of 0.35%, and the content of water (the major impurity) was 8.5%, with an expanded uncertainty of 0.32%. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Supersonic Bare Metal Cluster Beams. Technical Progress Report, March 16, 1984 - April 1, 1985

    Science.gov (United States)

    Smalley, R. E.

    1985-01-01

    There have been four major areas of concentration for the study of bare metal cluster beams: neutral cluster, chemical reactivity, cold cluster ion source development (both positive and negative), bare cluster ion ICR (ion cyclotron resonance) development, and photofragmentation studies of bare metal cluster ions.

  7. Performance Evaluation of a Multipurpose Bare PC Gateway

    DEFF Research Database (Denmark)

    Tsetse, Anthony; Appiah-Kubi, Patrick; Loukili, Alae

    2015-01-01

    Internet usage keeps growing daily with global internet traffic expected to quadruple by the end of 2015. This is as mainly due to increasing number of devices connecting to the internet and making data exchange much easier. This growth has impacted the current Internet Protocol version 4 being u...... results indicate a relatively better performance (18%-45%) of the Bare PC gateway compared to a Linux gateway (running the functionalities as standalone systems). We believe the proposed solution could easily scale to wide area networks and also provide a cost efficient solution...

  8. Rethinking biopower: posthumanism, bare life, and emancipatory work.

    Science.gov (United States)

    Cloyes, Kristin G

    2010-01-01

    This article answers a call, recently published in Advances in Nursing Science, to more fully explore the use of Italian political philosopher Giorgio Agamben's theory of biopower in nursing research and scholarship. Giorgio Agamben argues that biopower is not a modern phenomenon, and critical analysis of the historical origins of Western political practice shows how humanist discourse has been complicit in a long tradition of marginalization and violence, accomplished in each era by designating certain classes of human beings as "bare life." I discuss how I have used Agamben's theory to frame my own research, and the challenges of applying this theory in emancipatory work.

  9. Analysis of the Purity of Cetrimide by Titrations

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Rasmussen, Claus/Dallerup; Nielsen, Hans/Boye

    2006-01-01

    The purity of cetrimide, trimethyl tetradecyl ammonium bromide (TTAB), that is an important preservative of many cosmetic and pharmaceutical products, was determined by three independent methods of titration. Traditionally, cetrimide was analysed by an assay method of the European Pharmacopoeia (Ph...... the extraction step of the Ph. Eur.-assay method. The distribution coefficients between chloroform and water of cetrimide and the corresponding iodide species (TTAI) were thus determined as 2150 ± 50 M-1 and 68000 ± 4000 M-1, respectively....

  10. METHOD OF TESTING THERMAL NEUTRON FISSIONABLE MATERIAL FOR PURITY

    Science.gov (United States)

    Fermi, E.; Anderson, H.L.

    1961-01-24

    A process is given for determining the neutronic purity of fissionable material by the so-called shotgun test. The effect of a standard neutron absorber of known characteristics and amounts on a neutronic field also of known characteristics is measured and compared with the effect which the impurities derived from a known quantity of fissionable material has on the same neutronic field. The two readings are then made the basis of calculation from which the amount of impurities can be computed.

  11. Low-energy rate enhancement in recombination processes of electrons into bare uranium ions

    International Nuclear Information System (INIS)

    Wu Yong; Zeng Siliang; Duan Bin; Yan Jun; Wang Jianguo; Chinese Academy of Sciences, Lanzhou; Dong Chenzhong; Ma Xinwen

    2007-01-01

    Based on the Dirac-Fork-Slater method combined with the multichannel quantum defect theory, the recombination processes of electrons into bare uranium ions (U 92+ ) are investigated in the relative energy range close to zero, and the x-ray spectrum emitted in the direct radiative recombination and cascades processes are simulated. Compared with the recent measurement, it is found that the rate enhancement comes from the additional populations on high Rydberg states. These additional populations may be produced by other recombination mechanisms, such as the external electric-magnetic effects and the many-body correlation effects, which still remains an open problem. (authors)

  12. Various analytical techniques used for the measurement of isotopic purity of heavy water at Madras Atomic Power Station

    International Nuclear Information System (INIS)

    Satyanarayanan, V.; Umapathy, P.; Bhaskaran, R.; Nagarajan, J.; Pradeep, Jeena; Ayyar, S.R.

    2008-01-01

    The paper deals with the various techniques used for the measurement of isotopic purity of heavy water samples received from different sources viz. reactor systems, heavy water upgrading plant and fresh consignment from heavy water production plants. Heavy water is used in PHWRs as moderator and primary coolant. Isotopic Purity is an important parameter to be monitored/analysed regularly for both the systems. There is a minimum isotopic purity level to be maintained in the moderator system due to neutron economy/fuel burnup and in the case of coolant system the measurement is of paramount importance due to its safety considerations. The selection of the method of analysis depends on the isotopic range. The techniques used to measure the isotopic purity of heavy water are a) Infrared Spectrophotometry b) Refractometry c) Densitometry. Infrared spectrometer uses the property of molecular absorption of IR radiation by HOD species and the absorbance is the measure of isotopic purity. This technique is generally used for measuring high isotopic (80-99.98%) and low isotopic samples. Refractometer uses the property of refractive index of heavy water. The difference in refractive indices of light water and heavy water is 0.0048. A 1 % change in D 2 O concentration would thus equal to 0.000048 refractive index units. This method is used for determining the approximate isotopic value of a sample. Density meter uses the property of difference in densities of light and heavy water. The difference in density of 99.999% D 2 O and light water is 0.107540 which covers the whole range of interest. The experience gained with these techniques in the measurements of isotopic purity of various samples are presented in this paper. (author)

  13. On the purity assessment of solid sodium borohydride

    Science.gov (United States)

    Botasini, Santiago; Méndez, Eduardo

    2012-01-01

    Since sodium borohydride has become extensively used as chemical hydrogen storage material in fuel cells, many techniques have been proposed to assess the purity of this substance. However, all of them are developed in aqueous media, where the reagent is unstable. In addition, its hygroscopic nature was difficults in any attempt to make precise quantifications. The present work compares three different methods, namely, voltammetric, titrimetric, and Fourier transformed infrared spectroscopy (FTIR) in order to assess the purity of sodium borohydride, using an expired and a new sodium borohydride samples as references. Our results show that only the FTIR measurements provide a simple and semi-quantitative means to assess the purity of sodium borohydride due to the fact that it is the only one that measures the sample in the solid state. A comparison between the experimental data and theoretical calculation reveals the identification of the absorption bands at 1437 cm-1 of sodium metaborate and 2291 cm-1 of sodium borohydride which represent a good fingerprint for the qualitative assessment of the sample quality.

  14. 7 CFR 201.51b - Purity procedures for coated seed.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Purity procedures for coated seed. 201.51b Section 201... SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Purity Analysis in the Administration of the Act § 201.51b Purity...

  15. Quantum thermalization of two coupled two-level systems in eigenstate and bare-state representations

    International Nuclear Information System (INIS)

    Liao Jieqiao; Huang Jinfeng; Kuang Leman

    2011-01-01

    We study analytically the quantum thermalization of two coupled two-level systems (TLSs), which are connected with either two independent heat baths (IHBs) or a common heat bath (CHB). We understand the quantum thermalization in eigenstate and bare-state representations when the coupling between the two TLSs is stronger and weaker than the TLS-bath couplings, respectively. In the IHB case, we find that, when the two IHBs have the same temperatures, the two coupled TLSs in eigenstate representation can be thermalized with the same temperature as those of the IHBs. However, in the case of two IHBs at different temperatures, just when the energy detuning between the two TLSs satisfies a special condition, the two coupled TLSs in eigenstate representation can be thermalized with an immediate temperature between those of the two IHBs. In bare-state representation, we find a counterintuitive phenomenon that, under some conditions, the temperature of the TLS connected with the high-temperature bath is lower than that of the other TLS, which is connected with the low-temperature bath. In the CHB case, the coupled TLSs in eigenstate representation can be thermalized with the same temperature as that of the CHB in nonresonant cases. In bare-state representation, the TLS with a larger energy separation can be thermalized to a thermal equilibrium with a lower temperature. In the resonant case, we find a phenomenon of antithermalization. We also study the steady-state entanglement between the two TLSs in both the IHB and CHB cases.

  16. Benthic metabolism and denitrification in a river reach: a comparison between vegetated and bare sediments

    Directory of Open Access Journals (Sweden)

    Pierluigi VIAROLI

    2009-02-01

    Full Text Available This study aims at comparing biogeochemical processes in a Vallisneria spiralis meadow and in unvegetated sediments in the upper reach of the Mincio River (Northern Italy. The main hypothesis of this work is that meadows of rooted macrophytes affect benthic metabolism, enhancing capacity to retain nutrients (assimilation and dissipate (denitrification nitrogen loadings. In order to highlight how plants affect benthic processes in the riverbed, oxygen, dissolved inorganic carbon (DIC, soluble reactive phosphorus (SRP and inorganic nitrogen fluxes, together with denitrification rates, were measured from February to November 2007 in intact cores collected from stands of V. spiralis and bare sediments. V. spiralis biomass, elemental composition and growth rates were concurrently measured. Macrophyte biomass ranged from 60 to 120 g m-2 (as dry matter; growth rates followed a seasonal pattern from 0.001 in winter up to 0.080 d-1 in summer. On an annual basis, the macrophyte meadow was autotrophic with net O2 production and dissolved inorganic carbon uptake, while the bare sediment was net heterotrophic. The concurrent N assimilation by macrophytes and losses through denitrification led to similar N uptake/dissipation rates, up to 2500 mmol m-2 y-1. Under the very high NO3 - concentrations of the Mincio River, the competition between primary production and denitrification processes was also avoided. A significant ammonium regeneration from sediments to the water column occurred in the V. spiralis meadow, where plant debris and particulate matter accumulated. Here, SRP was also released into the water column, whilst in the bare sediment SRP fluxes were close to zero. Overall, V. spiralis affected the benthic metabolism enhancing the ecosystem capacity to control nitrogen contamination. However, the actual N removal rates were not sufficient to mitigate the pollution discharge.

  17. Comparison of different methods of image analysis for quantifying bare soil in rangelands

    Science.gov (United States)

    Pulido Fernández, M.; Lavado Contador, J. F.; Schnabel, S.; Gómez Gutiérrez, Á.

    2009-04-01

    Many authors emphasize the importance of vegetation in maintaining low levels of soil loss by means of its positive influence in reducing erosion. In some low-vegetated Mediterranean rangelands, especially those with high livestock densities, water erosion can ultimately lead to a partial or total loss of soils, particularly at the beginning of the rainy season, when the surface cover is reduced after the dry summer period. In relation with this, it is essential to develop accurate methods allowing the quantification of bare soil which, in turn, can inform about the influence of different livestock management alternatives over the land system. The main goal of this work is the comparison of the ability of various pixel-based as well as object-oriented methods of image classification for the quantification of bare soil at a fine spatial resolution. The study area is a farm located in a woody rangeland (dehesa) in SW Spain covering a surface area of 1,024 hectare. A three bands (RGB) orthophoto image with a pixel size of 0,4 metres was used, together with its brightness component, to compare the classification of bare soil vs covered soil by means of the following methods: unsupervised classification (k-means algorithm), supervised classification (maximum likelihood classification, minimum distance or nearest neighbour and Mahalanobis distance) and object oriented classification through a multiresolution segmentation. The results of classification were tested using 700 to 1000 points of field validation. Different combinations of image layers as well as validation algorithms were applied to assess for the better classification results. The best unsupervised classification was obtained from a combination of the RGB layers with the brightness component of the image. A total of 93.1 % of the field data were correctly classified and the Area Under the Curve (AUC) obtained with the ROC (Receiving Operating Characteristic) validation technique amounted to 0.91. With this

  18. Effect of argon purity on mechanical properties, microstructure and fracture mode of commercially pure (cp) Ti and Ti-6Al-4V alloys for ceramometal dental prostheses

    International Nuclear Information System (INIS)

    Bauer, Jose; Cella, Suelen; Pinto, Marcelo M; Filho, Leonardo E Rodrigues; Reis, Alessandra; Loguercio, Alessandro D

    2009-01-01

    Provision of an inert gas atmosphere with high-purity argon gas is recommended for preventing titanium castings from contamination although the effects of the level of argon purity on the mechanical properties and the clinical performance of Ti castings have not yet been investigated. The purpose of this study was to evaluate the effect of argon purity on the mechanical properties and microstructure of commercially pure (cp) Ti and Ti-6Al-4V alloys. The castings were made using either high-purity and/or industrial argon gas. The ultimate tensile strength (UTS), proportional limit (PL), elongation (EL) and microhardness (VHN) at different depths were evaluated. The microstructure of the alloys was also revealed and the fracture mode was analyzed by scanning electron microscopy. The data from the mechanical tests and hardness were subjected to a two-and three-way ANOVA and Tukey's test (α = 0.05). The mean values of mechanical properties were not affected by the argon gas purity. Higher UTS, PL and VHN, and lower EL were observed for Ti-6Al-4V. The microhardness was not influenced by the argon gas purity. The industrial argon gas can be used to cast cp Ti and Ti-6Al-4V.

  19. Effect of argon purity on mechanical properties, microstructure and fracture mode of commercially pure (cp) Ti and Ti-6Al-4V alloys for ceramometal dental prostheses

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Jose [Department of Dentistry I, School of Dentistry, University Federal of Maranhao, Campus Universitario do Bacanga, Av. dos Portugueses, s/n, 65085680, Sao Luis/MA (Brazil); Cella, Suelen; Pinto, Marcelo M; Filho, Leonardo E Rodrigues [Department of Dental Materials, School of Dentistry, University of Sao Paulo, Av. Prof. Lineu Prestes, 2227, 05508-900, Sao Paulo/SP (Brazil); Reis, Alessandra; Loguercio, Alessandro D, E-mail: jrob@usp.b [Department of Restorative Dentistry, Universidade Estadual de Ponta Grossa Av. General Carlos Cavalcanti, 4748, Bloco M, Sala 64 A, 84030-900, Ponta Grossa/PR (Brazil)

    2009-12-15

    Provision of an inert gas atmosphere with high-purity argon gas is recommended for preventing titanium castings from contamination although the effects of the level of argon purity on the mechanical properties and the clinical performance of Ti castings have not yet been investigated. The purpose of this study was to evaluate the effect of argon purity on the mechanical properties and microstructure of commercially pure (cp) Ti and Ti-6Al-4V alloys. The castings were made using either high-purity and/or industrial argon gas. The ultimate tensile strength (UTS), proportional limit (PL), elongation (EL) and microhardness (VHN) at different depths were evaluated. The microstructure of the alloys was also revealed and the fracture mode was analyzed by scanning electron microscopy. The data from the mechanical tests and hardness were subjected to a two-and three-way ANOVA and Tukey's test (alpha = 0.05). The mean values of mechanical properties were not affected by the argon gas purity. Higher UTS, PL and VHN, and lower EL were observed for Ti-6Al-4V. The microhardness was not influenced by the argon gas purity. The industrial argon gas can be used to cast cp Ti and Ti-6Al-4V.

  20. Polarimetric purity and the concept of degree of polarization

    Science.gov (United States)

    Gil, José J.; Norrman, Andreas; Friberg, Ari T.; Setälä, Tero

    2018-02-01

    The concept of degree of polarization for electromagnetic waves, in its general three-dimensional version, is revisited in the light of the implications of the recent findings on the structure of polarimetric purity and of the existence of nonregular states of polarization [J. J. Gil et al., Phys Rev. A 95, 053856 (2017), 10.1103/PhysRevA.95.053856]. From the analysis of the characteristic decomposition of a polarization matrix R into an incoherent convex combination of (1) a pure state Rp, (2) a middle state Rm given by an equiprobable mixture of two eigenstates of R, and (3) a fully unpolarized state Ru -3 D, it is found that, in general, Rm exhibits nonzero circular and linear degrees of polarization. Therefore, the degrees of linear and circular polarization of R cannot always be assigned to the single totally polarized component Rp. It is shown that the parameter P3 D proposed formerly by Samson [J. C. Samson, Geophys. J. R. Astron. Soc. 34, 403 (1973), 10.1111/j.1365-246X.1973.tb02404.x] takes into account, in a proper and objective form, all the contributions to polarimetric purity, namely, the contributions to the linear and circular degrees of polarization of R as well as to the stability of the plane containing its polarization ellipse. Consequently, P3 D constitutes a natural representative of the degree of polarimetric purity. Some implications for the common convention for the concept of two-dimensional degree of polarization are also analyzed and discussed.

  1. Chemical and radiochemical evaluation of the purity of sup(99m)Tc extracted by MEK

    International Nuclear Information System (INIS)

    Narasimhan, D.V.S.; Mani, R.S.

    1976-01-01

    Solvent extraction separation of sup(99m)Tc from 99 Mo using methyl ethyl ketone (MEK) has been found to be an effective method of obtaining sup(99m)Tc of medicinal purity from low specific activity 99 Mo. The authors have investigated the effect of alkali and molybdenum concentration on the extraction of 99 Mo and sup(99m)Tc into methyl ethyl ketone. The possibility of methyl ethyl ketone forming enol and condensation products and its effect on the final extraction efficiency and purity of sup(99m)Tc has been studied. Sodium molibdate has been found to have a good salting out effect on sup(99m)Tc pertechnetate and hence sup(99m)Tc extraction can be better accomplished from low specific activity 99 Mo solutions. The ketone seems to form traces of condensation products in the extraction procedure. These have been found to be coextracted with sup(99m)Tc into MEK but did not affect the extractability of sup(99m)Tc. It was observed that natural alumina column removes these condensation products from MEK containing sup(99m)Tc. Alternately these could be filtered off by acidification of the final aqueous sup(99m)Tc solution. The studies indicate that under optimum experimental conditions methyl ethyl ketone separates sup(99m)Tc from 99 Mo with high efficiency and yields sup(99m)Tc of high purity suitable for use in nuclear medicine in the form of various labelled compounds. (T.G.)

  2. Development of one-dimensional atmosphere-bare soil model

    Energy Technology Data Exchange (ETDEWEB)

    Yamazawa, Hiromi; Nagai, Haruyasu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-10-01

    As the first step of modeling of dynamical behaviors of air and water as media of radionuclide migration in the atmosphere-vegetation-soil system, a one-dimensional numerical model of atmosphere-bare soil system was developed. The atmospheric part, which is based on the existing one-dimensional meteorological model PHYD1V3, consists of prognostic equations for horizontal wind components, potential temperature, specific humidity, fog water, turbulence kinetic energy and turbulence length scale. This part also consists of a second-order turbulence closure model and solar-atmospheric radiation model. The soil part consists of prognostic equations for soil temperature, volumetric water content and specific humidity in soil air. Both parts are interfaced to each other with the ground surface water and heat budget equations. This model employs a finite difference scheme with multi-layer description for the both part. (author)

  3. Ionization of uracil in collisions with fast bare ions

    Science.gov (United States)

    Tribedi, L. C.; Agnihotri, A. N.; Galassi, M. E.; Rivarola, R. D.; Champion, C.

    2012-11-01

    We study the atomic collisions with large molecules and simple atoms. The ionization and fragmentation spectra are investigated for uracil, a RNA base molecule, under the impact of fast bare C, O and F-ions. The experiments are conducted using a recoil-ion time-of-flight spectrometer. The energy dependence of the total ionization cross sections (TCS) and fragmentation yields are measured for MeV/u energies. In addition, the angular distribution of the electron double differential cross sections (DDCS) are also shown in some cases. The total cross sections of ionization and also the DDCS data are compared with the CDW-EIS calculations. The qualitative agreement is good but, in general, the theory tends to overestimate the data by a factor of 2.2. The angular distribution of electrons clearly indicates a good qualitative agreement except for the lowest energy electrons.

  4. Bumblebees (Bombus terrestris) and honeybees (Apis mellifera) prefer similar colours of higher spectral purity over trained colours.

    Science.gov (United States)

    Rohde, Katja; Papiorek, Sarah; Lunau, Klaus

    2013-03-01

    Differences in the concentration of pigments as well as their composition and spatial arrangement cause intraspecific variation in the spectral signature of flowers. Known colour preferences and requirements for flower-constant foraging bees predict different responses to colour variability. In experimental settings, we simulated small variations of unicoloured petals and variations in the spatial arrangement of colours within tricoloured petals using artificial flowers and studied their impact on the colour choices of bumblebees and honeybees. Workers were trained to artificial flowers of a given colour and then given the simultaneous choice between three test colours: either the training colour, one colour of lower and one of higher spectral purity, or the training colour, one colour of lower and one of higher dominant wavelength; in all cases the perceptual contrast between the training colour and the additional test colours was similarly small. Bees preferred artificial test flowers which resembled the training colour with the exception that they preferred test colours with higher spectral purity over trained colours. Testing the behaviour of bees at artificial flowers displaying a centripetal or centrifugal arrangement of three equally sized colours with small differences in spectral purity, bees did not prefer any type of artificial flowers, but preferentially choose the most spectrally pure area for the first antenna contact at both types of artificial flowers. Our results indicate that innate preferences for flower colours of high spectral purity in pollinators might exert selective pressure on the evolution of flower colours.

  5. A universal quantitative ¹H nuclear magnetic resonance (qNMR) method for assessing the purity of dammarane-type ginsenosides.

    Science.gov (United States)

    Li, Ze Yun; Welbeck, Edward; Wang, Ru Feng; Liu, Qing; Yang, Ying Bo; Chou, Gui Xin; Bi, Kai Shun; Wang, Zheng Tao

    2015-01-01

    Quantitative (1)H-NMR (qNMR) is a well-established method for quantitative analysis and purity tests. Applications have been reported in many areas, such as natural products, foods and beverages, metabolites, pharmaceuticals and agriculture. The characteristics of quantitative estimation without relying on special target reference substances make qNMR especially suitable for purity tests of chemical compounds and natural products. Ginsenosides are a special group of natural products drawing broad attention, and are considered to be the main bioactive principles behind the claims of ginsengs efficacy. The purity of ginsenosides is usually determined by conventional chromatographic methods, although these may not be ideal due to the response of detectors to discriminate between analytes and impurities and the long run times involved. To establish a qNMR method for purity tests of six dammarane-type ginsenoside standards. Several experimental parameters were optimised for the quantification, including relaxation delay (D1), the transmitter frequency offset (O1P) and power level for pre-saturation (PL9). The method was validated and the purity of the six ginsenoside standards was tested. Also, the results of the qNMR method were further validated by comparison with those of high performance liquid chromatography. The qNMR method was rapid, specific and accurate, thus providing a practical and reliable protocol for the purity analysis of ginsenoside standards. Copyright © 2014 John Wiley & Sons, Ltd.

  6. Laser damage of HR, AR-coatings, monolayers and bare surfaces at 1064 nm

    Science.gov (United States)

    Garnov, S. V.; Klimentov, S. M.; Said, A. A.; Soileau, M. J.

    1993-01-01

    Laser induced damage thresholds and morphologies were investigated in a variety of uncoated and coated surfaces, including monolayers and multi-layers of different chemical compositions. Both antireflective (AR) and highly reflective (HR) were tested. Testing was done at 1064 nm with 25 picosecond and 8 nanosecond YAG/Nd laser single pulses. Spot diameter in the experiments varied from 0.09 to 0.22 mm. The laser damage measurement procedure consisted of 1-on-1 (single laser pulse in the selected site) and N-on-1 experiments including repeated irradiation by pulses of the same fluence and subsequently raised from pulse to pulse fluence until damage occurred. The highest picosecond damage thresholds of commercially available coatings averaged 12 - 14 J/sq cm, 50 percent less than thresholds obtained in bare fused silica. Some coatings and bare surfaces revealed a palpable preconditioning effect (an increase in threshold of 1.2 to 1.8 times). Picosecond and nanosecond data were compared to draw conclusions about pulse width dependence. An attempt was made to classify damage morphologies according to the type of coating, class of irradiating, and damage level.

  7. Oralloy (93.2 235U) Bare Metal Annuli And Disks

    Energy Technology Data Exchange (ETDEWEB)

    Hummel, Andrew John [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    A multitude of critical experiments with highly enriched uranium metal were conducted in the 1960s and 1970s at the Oak Ridge Critical Experiments Facility (ORCEF) in support of criticality safety operations at the Y-12 Plant. These experiments served to evaluate the storage, casting, and handling limits for the Y-12 Plant while also providing data for verification of different calculation methods and associated cross-sections for nuclear criticality safety applications. These included both solid cylinders and annuli of various diameters, interacting cylinders of various diameters, parallelepipeds, and reflected cylinders and annuli. The experiments described here involve a series of delayed critical stacks of bare oralloy HEU annuli and disks. Three of these experiments consist of stacking bare HEU annuli of varying diameters to obtain critical configurations. These annuli have nominal inner and outer diameters (ID/OD) including: 7 inches (") ID – 9" OD, 9" ID – 11" OD, 11" ID – 13" OD, and 13? ID – 15" OD. The nominal heights range from 0.125" to 1.5". The three experiments themselves range from 7" – 13", 7" – 15", and 9" – 15" in diameter, respectively. The fourth experiment ranges from 7" – 11", and along with different annuli, it also includes an 11" disk and several 7" diameter disks. All four delayed critical experiments were configured and evaluated by J. T. Mihalczo, J. J. Lynn, and D. E. McCarty from December of 1962 to February 1963 with additional information in their corresponding logbook.

  8. A 99 percent purity molecular sieve oxygen generator

    Science.gov (United States)

    Miller, G. W.

    1991-01-01

    Molecular sieve oxygen generating systems (MSOGS) have become the accepted method for the production of breathable oxygen on military aircraft. These systems separate oxygen for aircraft engine bleed air by application of pressure swing adsorption (PSA) technology. Oxygen is concentrated by preferential adsorption in nitrogen in a zeolite molecular sieve. However, the inability of current zeolite molecular sieves to discriminate between oxygen and argon results in an oxygen purity limitations of 93-95 percent (both oxygen and argon concentrate). The goal was to develop a new PSA process capable of exceeding the present oxygen purity limitations. A novel molecular sieve oxygen concentrator was developed which is capable of generating oxygen concentrations of up to 99.7 percent directly from air. The process is comprised of four absorbent beds, two containing a zeolite molecular sieve and two containing a carbon molecular sieve. This new process may find use in aircraft and medical breathing systems, and industrial air separation systems. The commercial potential of the process is currently being evaluated.

  9. Chernozem aggregate waterstability loss investigation in a long-term bare fallow experiment

    Science.gov (United States)

    Vasilyeva, N. A.; Milanovskiy, E. Y.

    2009-04-01

    -year bare fallow show that overall decrease in Corg under bare fallow is about 50% due to loss of light fractions, 30% due to loss in clay fraction and 15% due to loss in coarse silt medium fraction. Light fraction has predominant particle sizes of D10-D90=(2-20) mkm in fine silt and (7-70 mkm) in coarse silt. Light fraction particles are mostly hydrophobic in nature and may function as high contact seals between soil particles, enhancing hydrophobic interactions within aggregate in the presence of water, and preventing its rapid entrance into the aggregate. Reduction of light fractions fivefold and the increase in SSA (opening of clogged pores) due to overall loss in Corg content allow more rapid water move into the aggregate. Moreover, stable residual of light fraction under bare fallow becomes extremely water-repellent which should make the aggregate system unstable upon water percolation. We observe mineralization and washing out of low-molecular hydrophilic HS from bare fallow soil components. Hydrophilic HS may function as bonding mediators between mineral particles and high-molecular hydrophobic HS. Therefore we propose that disruption of aggregate waterstability results from SOM hydrophilic-hydrophobic disbalance. Molecular parameters of HS hydrophobic and hydrophilic components are substantially different. The enhancement in hydrophobic interaction ability of HS components is accompanied by increase in molecular weight and Corg content, and decrease in nitrogen content. Waterstable aggregates are shown to contain HS with stronger hydrophobic properties than that of dry-sieving ones and it results in a more pronounced reduction of SSA upon waterstable aggregation. The experimental results give evidence and characteristics of at least four SOM pools in a typical chernozem soil: degradable sorbed SOM (accounts for 0.9% of Corg content), which probably includes dissolvable SOM, degradable particulate organic matter (POM) (1.1%), stable sorbed SOM (2%) and stable

  10. A fast method for the determination of the efficiency coefficient of bare CR-39 detector

    International Nuclear Information System (INIS)

    Dwaikat, Nidal; El-hasan, Mousa; Sueyasu, Masto; Kada, Wataru; Sato, Fuminobu; Kato, Yushi; Saffarini, G.; Iida, Toshiyuki

    2010-01-01

    A fast and simple method for the determination of the efficiency coefficient (η) of bare CR-39 detector is presented and discussed. The efficiency coefficient of bare CR-39 detector is then calculated by different ways and the obtained values are found to be comparable to each other. The average value of η of bare CR-39 is found to be 0.20 ± 0.01 tracks cm -2 day -1 per Bq m -3 .

  11. A fast method for the determination of the efficiency coefficient of bare CR-39 detector

    Energy Technology Data Exchange (ETDEWEB)

    Dwaikat, Nidal, E-mail: nidaldwaiakt@yahoo.co [Department of Electronics, Information Systems and Energy Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka (Japan); Department of Physics, An-Najah National University, Nablus, Palestine (Country Unknown); El-hasan, Mousa [Department of Physics, An-Najah National University, Nablus, Palestine (Country Unknown); Sueyasu, Masto; Kada, Wataru; Sato, Fuminobu; Kato, Yushi [Department of Electronics, Information Systems and Energy Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka (Japan); Saffarini, G. [Department of Physics, An-Najah National University, Nablus, Palestine (Country Unknown); Iida, Toshiyuki [Department of Electronics, Information Systems and Energy Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka (Japan)

    2010-10-15

    A fast and simple method for the determination of the efficiency coefficient ({eta}) of bare CR-39 detector is presented and discussed. The efficiency coefficient of bare CR-39 detector is then calculated by different ways and the obtained values are found to be comparable to each other. The average value of {eta} of bare CR-39 is found to be 0.20 {+-} 0.01 tracks cm{sup -2} day{sup -1} per Bq m{sup -3}.

  12. Sensitivity of mountain glacier mass balance to changes in bare-ice albedo

    OpenAIRE

    Naegeli, Kathrin; Huss, Matthias

    2017-01-01

    Albedo is an important parameter in the energy balance of bare-ice surfaces and modulates glacier melt rates. The prolongation of the ablation period enforces the albedo feedback and highlights the need for profound knowledge on impacts of bare-ice albedo on glacier mass balance. In this study, we assess the mass balance sensitivity of 12 Swiss glaciers with abundant long-term in-situ data on changes in bare-ice albedo. We use pixel-based bare-ice albedo derived from Landsat 8. A distributed ...

  13. Water evaporation from bare soil at Paraiba, Brazil

    International Nuclear Information System (INIS)

    Lima, Jose Romualdo de Sousa; Antonino, Antonio Celso D.; Lira, Carlos A. Brayner de O.; Maciel Netto, Andre; Silva, Ivandro de Franca da; Souza, Jeffson Cavalcante de

    2002-01-01

    Measurements were accomplished in a 4,0 ha area in Centro de Ciencias Agrarias, UFPB, Areia City, Paraiba State, Brazil (6 deg C 58'S, 35 deg C 41'W and 645 m), aiming to determine water evaporation from bare soil, by energy and water balance approaches. Rain gauge, net radiometer, pyranometer and sensor for measuring the temperature and the relative humidity of the air and the speed of the wind, in two levels above the soil surface, were used to solve the energy balance equations. In the soil, two places were fitted with instruments, each one with two thermal probes, installed horizontally in the depths z1 = 2,0 cm and z2 = 8,0 cm, and a heat flux plate, for the measurement of the heat flux in the soil, the z1 = 5,0 cm. The measured data were stored every 30 minutes in a data logger. For the calculation of the water balance, three tensio-neutronics sites were installed, containing: an access tube for neutrons probe and eight tensiometers. The values of soil evaporation obtained by water balance were lower than obtained by energy balance because of the variability of the water balance terms. (author)

  14. Measurement of optical purity of p-BPA-Tyrosine dipeptide

    Energy Technology Data Exchange (ETDEWEB)

    Yoshino, K.; Sato, N.; Kitta, K.; Saitake, Y. [Shinshu Univ., Faculty of Science, Matsumoto, Nagano (Japan); Hiratsuka, J. [Kawasaki Medical School, Dept. of Radiation Oncology, Kurashiki, Okayama (Japan); Ichihashi, M. [Kobe Univ. (Japan). School of Medicine

    2000-10-01

    Melanin biosynthesis is very active in melanoma cells, and tyrosine is one of the substrates of the melanin biosynthesis. Tyrosine is oxidized to dopa by tyrosinase at the beginning of melanin biosynthesis process. Therefore, p-boronophenylalanine (BPA)-tyrosine dipeptide is expected to be a substrate of melanin biosynthesis process, and the peptide will be incorporated in melanoma cells, and then tumor boron concentration lasts in their cells for long time. Since p-BPA tyrosine are amino acids, they have D, L isomers. Therefore, we have tried to synthesize four isomers (L-L, L-D, D-L, D-D) of p-BPA-Tyrosine dipeptide, and have measured their optical purity with HPLC. (author)

  15. Lost Purity. Social in Nineteenth and Twentieth-century Feminisms

    Directory of Open Access Journals (Sweden)

    Paola Persano

    2016-07-01

    Full Text Available ‘Social Purity’ appears in a part of the French and Anglo-Saxon (Britain and the United States nineteenth-twentieth century’s feminisms, as a mean for many claims: from the full recognition of sexual difference in Hubertine Auclert’s social and ‘differentialist’ republicanism in France to Josephine Butler’s refusal of any purity imposed from above in England, until the absolute turn of the idea of women’s moral superiority and the equal and opposite force to the final exit from ‘the social’ by the American ‘New Womanism’, individualizing and de-feminizing the act of sexual liberation. All this in a continuous play of actions and reactions, sometimes paradoxical, weaving together suffragism and anti-suffragism, contestation of the conjugal complementarity and the never overcome temptations of hetero or self-control.

  16. Supply-side response to declining heroin purity: fentanyl overdose episode in New Jersey.

    Science.gov (United States)

    Hempstead, Katherine; Yildirim, Emel O

    2014-06-01

    The inelastic price demand observations characteristic of illegal drug markets have led to the conclusion that the burden of a negative supply shock would be completely reflected to consumers. This paper argues that the increasing availability of prescription opioids may threaten heroin sellers' profit margin and force them to find alternative methods to compensate buyers in the event of a supply shock. We investigate the 2006 fentanyl overdose episode in New Jersey and argue that the introduction of non-pharmaceutical fentanyl, its spatial distribution, and the timing of overdose deaths may have been related to trends in heroin purity. Using medical examiner data, as well as data from the Drug Enforcement Administration, Office of Diversion Control on retail sales of prescription opioids in a negative binomial specification, we show that month-to-month fluctuations in heroin purity have a significant effect on fentanyl-related overdoses, particularly in those areas where prescription opioids are highly available. Copyright © 2013 John Wiley & Sons, Ltd.

  17. A simple two-strip method to determine the radiochemical purity of technetium-99m mercaptoacetyltriglycine

    International Nuclear Information System (INIS)

    Chen Fang; Decristoforo, C.; Rohrbacher, B.; Riccabona, G.

    1993-01-01

    Technetium-99m mercaptoacetyltriglycine (MAG3) has been used extensively as a renal function agent for several years. Radioimpurities in the MAG3 kit preparation are not only concentrated and excreted in the kidneys. Therefore proper quality control for renal studies is even more important to make possible a rapid and adequate interpretation of diagnostic studies. The standard method to determine the radiochemical purity is high-performance liquid chromatography (HPLC), which is time consuming and expensive. We set up a new simple thin-layer chromatography (TLC) method based on instant thin-layer silica gel strips as statitionary phase for ching the main impurities, free pertechnetate and reduced hydrolysed 99m Tc-colloid. Comparison of TLC and HPLC results showed no significant differences (t-test, P 99m Tc-colloid. The main impurity found in 37 routine preparations was free pertechnetate; the mean radiochemical purity was 97.95%. The time required to perform the analysis was less than 20 min. The new TLC system is a cheap, simple, fast, reliable and accurate method for the quality control of the MAG3 kit preparation, and is especially suitable for routine use. (orig.)

  18. Low purity glycerin supplementation in grazing cattle: bioeconomic analysis

    Directory of Open Access Journals (Sweden)

    Evani Souza de Oliveira Strada

    2015-07-01

    Full Text Available This study aimed to evaluate the dry matter intake, digestibility of diet components, performance, feed conversion, carcass characteristics and economics aspects of inclusion with low purity glycerin supplementation on cattle finished on pasture with Brachiaria decumbens. We used 35 male cattle bulls, predominantly Nellore, with initial body weight of 428.0 ± 32.11 kg, distributed in a completely randomized design with five treatments and seven replications. Treatments consisted of glycerin inclusion levels (0, 3, 6, 9 and 12% in the dry matter (DM. The animals were weighed every 28 days to assess the weight gain (ADG and adjust the diet. At the end of the experiment the animals were weighed to obtain the average final body weight (BWF and slaughtered to evaluate the carcass yield (HCY and carcass traits. The economic analysis was conducted in relation to weight gain in kilos, in order to verify the feasibility of the use of diets with five levels of glycerin, without considering other fixed and operational costs. Increased linearly (P <0.05 levels of glycerin on the intake and digestibility of ether extract and ADG. Linear effect (P <0.05 on the digestibility of neutral detergent fiber (CDFDN, crude protein (CDCP and feed conversion (FC. No effects were observed (P <0.05 the inclusion of glycerin on carcass traits evaluated. The inclusion of glycerin reduced the cost of production of meat at sign when the price of this ingredient represented up to 70% of the price of corn. Glycerin low purity can be included in the diet of cattle uncastrated finishing the pasture with improved performance and ncreased economic benefits.

  19. Liquid argon as active shielding and coolant for bare germanium detectors. A novel background suppression method for the GERDA 0{nu}{beta}{beta} experiment

    Energy Technology Data Exchange (ETDEWEB)

    Peiffer, J.P.

    2007-07-25

    Two of the most important open questions in particle physics are whether neutrinos are their own anti-particles (Majorana particles) as required by most extensions of the StandardModel and the absolute values of the neutrino masses. The neutrinoless double beta (0{nu}{beta}{beta}) decay, which can be investigated using {sup 76}Ge (a double beta isotope), is the most sensitive probe for these properties. There is a claim for an evidence for the 0{nu}{beta}{beta} decay in the Heidelberg-Moscow (HdM) {sup 76}Ge experiment by a part of the HdM collaboration. The new {sup 76}Ge experiment Gerda aims to check this claim within one year with 15 kg.y of statistics in Phase I at a background level of {<=}10{sup -2} events/(kg.keV.y) and to go to higher sensitivity with 100 kg.y of statistics in Phase II at a background level of {<=}10{sup -3} events/(kg.keV.y). In Gerda bare germanium semiconductor detectors (enriched in {sup 76}Ge) will be operated in liquid argon (LAr). LAr serves as cryogenic coolant and as high purity shielding against external background. To reach the background level for Phase II, new methods are required to suppress the cosmogenic background of the diodes. The background from cosmogenically produced {sup 60}Co is expected to be {proportional_to}2.5.10{sup -3} events/(kg.keV.y). LAr scintillates in UV ({lambda}=128 nm) and a novel concept is to use this scintillation light as anti-coincidence signal for background suppression. In this work the efficiency of such a LAr scintillation veto was investigated for the first time. In a setup with 19 kg active LAr mass a suppression of a factor 3 has been achieved for {sup 60}Co and a factor 17 for {sup 232}Th around Q{sub {beta}}{sub {beta}} = 2039 keV. This suppression will further increase for a one ton active volume (factor O(100) for {sup 232}Th and {sup 60}Co). LAr scintillation can also be used as a powerful tool for background diagnostics. For this purpose a new, very stable and robust wavelength

  20. Half-bare positron in the inner gap of a pulsar

    Science.gov (United States)

    Trofymenko, S. V.; Kontorovich, V. M.

    2017-12-01

    The pulsed radiation from the Crab Pulsar consists of the main pulse (MP) and inter pulse (IP), as well as of the extra pulse components appearing at certain frequencies. One of the mysteries of these data, found by Moffett and Hankins twenty years ago, is the shift of the IP at high radio frequencies compared to lower ones and return to its previous position in the higher-frequency optical and X-ray range. In previous paper we proposed the explanation of these mysterious changes with the frequency, applying the idea of the reflection of curvature radiation by relativistic positrons from the stellar surface. Presently we focus on the additional contribution of transition radiation, emitted when positron hits the surface, to the total pulse produced by the particle. It is shown that due to the 'half-bare' state of positron in the polar gap the considered contribution is significantly suppressed comparing to the one of reflected curvature radiation.

  1. Correlated radiative double electron capture (RDEC) in collisions of bare oxygen ions with carbon targets

    Science.gov (United States)

    Simon, A.; Tanis, J. A.; ElKafrawy, T.; Warczak, A.

    2009-11-01

    Multielectron capture processes observed in low energy collisions of bare ions give insight into electron-electron correlations in strong fields. The main intention of this experiment is to observe radiative double electron capture (RDEC) in collisions of bare oxygen ions at energies of a few MeV/u with carbon targets. Measured results are to be compared with recent theoretical calculations.

  2. Biolimus-eluting stents with biodegradable polymer versus bare-metal stents in acute myocardial infarction

    DEFF Research Database (Denmark)

    Räber, Lorenz; Kelbæk, Henning; Taniwaki, Masanori

    2014-01-01

    BACKGROUND: This study sought to determine whether the 1-year differences in major adverse cardiac event between a stent eluting biolimus from a biodegradable polymer and bare-metal stents (BMSs) in the COMFORTABLE trial (Comparison of Biolimus Eluted From an Erodible Stent Coating With Bare Metal...

  3. Limits on the heralding efficiencies and spectral purities of spectrally filtered single photons from photon-pair sources

    Science.gov (United States)

    Meyer-Scott, Evan; Montaut, Nicola; Tiedau, Johannes; Sansoni, Linda; Herrmann, Harald; Bartley, Tim J.; Silberhorn, Christine

    2017-06-01

    Photon pairs produced by parametric down-conversion or four-wave mixing can interfere with each other in multiport interferometers or carry entanglement between distant nodes for use in entanglement swapping. This requires the photons to be spectrally pure to ensure good interference and have high heralding efficiency to know accurately the number of photons involved and to maintain high rates as the number of photons grows. Spectral filtering is often used to remove noise and define spectral properties. For heralded single photons high purity and heralding efficiency are possible by filtering the heralding arm, but when both photons in typical pair sources are filtered, we show that the heralding efficiency of one or both of the photons is strongly reduced even by ideal spectral filters with 100% transmission in the passband: any improvement in reduced-state spectral purity from filtering comes at the cost of lowered heralding efficiency. We consider the fidelity to a pure, lossless single photon, symmetrize it to include both photons of the pair, and show this quantity is intrinsically limited for sources with spectral correlation. We then provide a framework for this effect for benchmarking common photon-pair sources and present an experiment where we vary the photon filter bandwidths and measure the increase in purity and corresponding reduction in heralding efficiency.

  4. Analysis of the Temporal Response of Coupled Asymmetrical Zero-Power Subcritical Bare Metal Reactor Systems

    Energy Technology Data Exchange (ETDEWEB)

    Klain, Kimberly L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-21

    The behavior of symmetrical coupled-core systems has been extensively studied, yet there is a dearth of research on asymmetrical systems due to the increased complexity of the analysis of such systems. In this research, the multipoint kinetics method is applied to asymmetrical zeropower, subcritical, bare metal reactor systems. Existing research on asymmetrical reactor systems assumes symmetry in the neutronic coupling; however, it will be shown that this cannot always be assumed. Deep subcriticality adds another layer of complexity and requires modification of the multipoint kinetics equations to account for the effect of the external neutron source. A modified set of multipoint kinetics equations is derived with this in mind. Subsequently, the Rossi-alpha equations are derived for a two-region asymmetrical reactor system. The predictive capabilities of the radiation transport code MCNP6 for neutron noise experiments are shown in a comparison to the results of a series of Rossi-alpha measurements performed by J. Mihalczo utilizing a coupled set of symmetrical bare highly-enriched uranium (HEU) cylinders. The ptrac option within MCNP6 can generate time-tagged counts in a cell (list-mode data). The list-mode data can then be processed similarly to measured data to obtain values for system parameters such as the dual prompt neutron decay constants observable in a coupled system. The results from the ptrac simulations agree well with the historical measured values. A series of case studies are conducted to study the effects of geometrical asymmetry in the coupling between two bare metal HEU cylinders. While the coupling behavior of symmetrical systems has been reported on extensively, that of asymmetrical systems remains sparse. In particular, it appears that there has been no previous research in obtaining the coupling time constants for asymmetrically-coupled systems. The difficulty in observing such systems is due in part to the inability to determine the

  5. Corrosion in Supercritical carbon Dioxide: Materials, Environmental Purity, Surface Treatments, and Flow Issues

    Energy Technology Data Exchange (ETDEWEB)

    Sridharan, Kumar; Anderson, Mark

    2013-12-10

    The supercritical CO{sub 2} Brayton cycle is gaining importance for power conversion in the Generation IV fast reactor system because of its high conversion efficiencies. When used in conjunction with a sodium fast reactor, the supercritical CO{sub 2} cycle offers additional safety advantages by eliminating potential sodium-water interactions that may occur in a steam cycle. In power conversion systems for Generation IV fast reactors, supercritical CO{sub 2} temperatures could be in the range of 30°C to 650°C, depending on the specific component in the system. Materials corrosion primarily at high temperatures will be an important issue. Therefore, the corrosion performance limits for materials at various temperatures must be established. The proposed research will have four objectives centered on addressing corrosion issues in a high-temperature supercritical CO{sub 2} environment: Task 1: Evaluation of corrosion performance of candidate alloys in high-purity supercritical CO{sub 2}: The following alloys will be tested: Ferritic-martensitic Steels NF616 and HCM12A, austenitic alloys Incoloy 800H and 347 stainless steel, and two advanced concept alloys, AFA (alumina forming austenitic) steel and MA754. Supercritical CO{sub 2} testing will be performed at 450°C, 550°C, and 650°C at a pressure of 20 MPa, in a test facility that is already in place at the proposing university. High purity CO{sub 2} (99.9998%) will be used for these tests. Task 2: Investigation of the effects of CO, H{sub 2}O, and O{sub 2} impurities in supercritical CO{sub 2} on corrosion: Impurities that will inevitably present in the CO{sub 2} will play a critical role in dictating the extent of corrosion and corrosion mechanisms. These effects must be understood to identify the level of CO{sub 2} chemistry control needed to maintain sufficient levels of purity to manage corrosion. The individual effects of important impurities CO, H{sub 2}O, and O{sub 2} will be investigated by adding them

  6. Purity, adulteration and price of drugs bought on-line versus off-line in the Netherlands.

    Science.gov (United States)

    van der Gouwe, Daan; Brunt, Tibor M; van Laar, Margriet; van der Pol, Peggy

    2017-04-01

    On-line drug markets flourish and consumers have high expectations of on-line quality and drug value. The aim of this study was to (i) describe on-line drug purchases and (ii) compare on-line with off-line purchased drugs regarding purity, adulteration and price. Comparison of laboratory analyses of 32 663 drug consumer samples (stimulants and hallucinogens) purchased between January 2013 and January 2016, 928 of which were bought on-line. The Netherlands. Primary outcome measures were (i) the percentage of samples purchased on-line and (ii) the chemical purity of powders (or dosage per tablet); adulteration; and the price per gram, blotter or tablet of drugs bought on-line compared with drugs bought off-line. The proportion of drug samples purchased on-line increased from 1.4% in 2013 to 4.1% in 2015. The frequency varied widely, from a maximum of 6% for controlled, traditional substances [ecstasy tablets, 3,4-methylenedioxy-methamphetamine (MDMA) powder, amphetamine powder, cocaine powder, 4-bromo-2,5-dimethoxyphenethylamine (2C-B) and lysergic acid diethylamide (LSD)] to more than a third for new psychoactive substances (NPS) [4-fluoroamphetamine (4-FA), 5/6-(2-aminopropyl)benzofuran (5/6-APB) and methoxetamine (MXE)]. There were no large differences in drug purity, yet small but statistically significant differences were found for 4-FA (on-line 59% versus off-line 52% purity for 4-FA on average, P = 0.001), MDMA powders (45 versus 61% purity for MDMA, P = 0.02), 2C-B tablets (21 versus 10 mg 2C-B/tablet dosage, P = 0.49) and ecstasy tablets (131 versus 121 mg MDMA/tablet dosage, P = 0.05). The proportion of adulterated samples purchased on-line and off-line did not differ, except for 4-FA powder, being less adulterated on-line (χ 2  = 8.3; P < 0.02). Drug prices were mainly higher on-line, ranging for various drugs from 10 to 23% higher than that of drugs purchased off-line (six of 10 substances: P < 0.05). Dutch drug users increasingly

  7. Soft landing of bare nanoparticles with controlled size, composition, and morphology

    Science.gov (United States)

    Johnson, Grant E.; Colby, Robert; Laskin, Julia

    2015-02-01

    Physical synthesis employing magnetron sputtering and gas aggregation in a modified commercial source has been coupled with size-selection and ion soft landing to prepare bare nanoparticles on surfaces with controlled coverage, size, composition, and morphology. Employing atomic force microscopy (AFM) and scanning electron microscopy (SEM), it is demonstrated that the size and coverage of nanoparticles on flat and stepped surfaces may be controlled using a quadrupole mass filter and the length of deposition, respectively. AFM shows that nanoparticles bind randomly to flat surfaces when soft landed at relatively low coverage (4 × 104 ions μm-2). On stepped surfaces at intermediate coverage (4 × 105 ions μm-2) nanoparticles bind along step edges forming extended linear chains. At the highest coverage (2 × 106 ions μm-2) nanoparticles form a continuous film on flat surfaces. On one surface with sizable defects, the presence of localized imperfections results in agglomeration of nanoparticles onto these features and formation of neighboring zones devoid of particles. Employing high resolution scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) the customized magnetron sputtering/gas aggregation source is demonstrated to produce bare single metal particles with controlled morphology as well as bimetallic alloy nanoparticles with defined core-shell structures of that are of interest to catalysis.Physical synthesis employing magnetron sputtering and gas aggregation in a modified commercial source has been coupled with size-selection and ion soft landing to prepare bare nanoparticles on surfaces with controlled coverage, size, composition, and morphology. Employing atomic force microscopy (AFM) and scanning electron microscopy (SEM), it is demonstrated that the size and coverage of nanoparticles on flat and stepped surfaces may be controlled using a quadrupole mass filter and the length of deposition, respectively. AFM shows

  8. Numerical Modeling of Water Flow and Salt Transport in Bare Saline Soil Subjected to Transient Evaporation

    Science.gov (United States)

    Geng, X.; Boufadel, M.; Saleh, F. S.

    2014-12-01

    It has been found that evaporation over bare soil plays an important role in subsurface solute transport processes. A numerical study, based on a density-dependent variably saturated groundwater flow model MARUN, was conducted to investigate subsurface flow and salt transport in bare saline aquifers subjected to transient evaporation. The bulk aerodynamic formulation was adopted to simulate transient evaporation rate at ground surface. Subsurface flow pattern, moisture distribution, and salt migration were quantified. Key factors likely affecting this process, including saturated hydraulic conductivity, capillary drive, air humidity, and surrounding water supply, were examined. The results showed that evaporation induced an upward flow pattern, which led to a high saline plume formed beneath the evaporation zone. In absence of surrounding water supply, as the humidity between the ground surface and air tended to equilibrium, evaporation-induced density gradient generated pore water circulations around the plume edge and caused the salt to migrate downwards with "finger" shapes. It was found that capillary properties and atmospheric condition had significant impacts on subsurface moisture distribution and salt migration in response to the evaporation. Larger capillary fringe and/or lower air humidity would allow evaporation to extract more water from the ground. It would induce a larger and denser saline plume formed beneath the evaporation zone. The results also suggested that the presence of the surrounding water supply (represented as a constant water table herein) could provide a steady evaporation rate at the ground surface; meanwhile, in response to the evaporation, a hydraulic gradient was formed from the water supply boundary, which induced an inclined upper saline plume with greater density far from the supply boundary.

  9. Spectral Analysis Related to Bare-Metal and Drug-Eluting Coronary Stent Implantation

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Rose Mary Ferreira Lisboa da, E-mail: roselisboa@cardiol.br [Faculdade de Medicina da UFMG, Divinópolis, MG (Brazil); Silva, Carlos Augusto Bueno [Faculdade de Medicina da UFMG, Divinópolis, MG (Brazil); Belo Horizonte, Hospital São João de Deus, Divinópolis, MG (Brazil); Greco, Otaviano José [Belo Horizonte, Hospital São João de Deus, Divinópolis, MG (Brazil); Moreira, Maria da Consolação Vieira [Faculdade de Medicina da UFMG, Divinópolis, MG (Brazil)

    2014-08-15

    The autonomic nervous system plays a central role in cardiovascular regulation; sympathetic activation occurs during myocardial ischemia. To assess the spectral analysis of heart rate variability during stent implantation, comparing the types of stent. This study assessed 61 patients (mean age, 64.0 years; 35 men) with ischemic heart disease and indication for stenting. Stent implantation was performed under Holter monitoring to record the spectral analysis of heart rate variability (Fourier transform), measuring the low-frequency (LF) and high-frequency (HF) components, and the LF/HF ratio before and during the procedure. Bare-metal stent was implanted in 34 patients, while the others received drug-eluting stents. The right coronary artery was approached in 21 patients, the left anterior descending, in 28, and the circumflex, in 9. As compared with the pre-stenting period, all patients showed an increase in LF and HF during stent implantation (658 versus 185 ms2, p = 0.00; 322 versus 121, p = 0.00, respectively), with no change in LF/HF. During stent implantation, LF was 864 ms2 in patients with bare-metal stents, and 398 ms2 in those with drug-eluting stents (p = 0.00). The spectral analysis of heart rate variability showed no association with diabetes mellitus, family history, clinical presentation, beta-blockers, age, and vessel or its segment. Stent implantation resulted in concomitant sympathetic and vagal activations. Diabetes mellitus, use of beta-blockers, and the vessel approached showed no influence on the spectral analysis of heart rate variability. Sympathetic activation was lower during the implantation of drug-eluting stents.

  10. Impact of precursor purity on optical properties and radiation detection of CsI:Tl scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Saengkaew, Phannee; Cheewajaroen, Kulthawat; Yenchai, Chadet; Thong-aram, Decho [Chulalongkorn University, Department of Nuclear Engineering, Faculty of Engineering, Bangkok (Thailand); Sanorpim, Sakuntam [Chulalongkorn University, Department of Physics, Faculty of Science, Bangkok (Thailand); Jitpukdee, Manit [Kasetsart University, Department of Applied Radiation and Isotope, Faculty of Science, Bangkok (Thailand); Yordsri, Visittapong; Thanachayanont, Chanchana [Ministry of Science and Technology, National Metal and Materials Technology Center, National Science and Technology Development Agency, Pathumthani (Thailand); Nuntawong, Noppadon [Ministry of Science and Technology, National Electronic and Computer Technology Center, National Science and Technology Development Agency, Pathumthani (Thailand)

    2016-08-15

    Cesium iodide doped with thallium (CsI:Tl) crystals was grown to develop the gamma-ray detectors by using low-cost raw materials. Effect of impurities on optical properties and radiation detection performance was investigated. By a modified homemade Bridgman-Stockbarger technique, CsI:Tl samples were grown in two levels of CsI and TlI reactant materials, i.e., having as a very high purity of 99.999 % and a high purity of 99.9 %. XRD measurements indicate CsI:Tl crystals having a good quality with a dominant (110) plane. Having a cubic structure, a lattice constant of CsI crystals of 0.4574 nm and a crystallite size of 43.539 nm were obtained. From the lower-purity raw materials, calcite was found in an orange crystal with a lattice constant of 0.4560 nm and a crystallite size of 43.089 nm. By PL measurements, the optical properties of the CsI:Tl crystals were analyzed. ∝540-nm-wavelength PL peak was observed from the colorless high-purity crystal, and ∝600-nm-wavelength PL peak was observed from the orange crystal. The brighter PL emission was obtained from the orange crystals suggesting impurities. CsI:Tl surface morphology by SEM exhibited a smooth surface with some parallel crystal facets. For electrical properties of high-quality CsI:Tl crystals, the electrical resistances were 230 ± 16 MΩ in cross-sectional direction and 714 ± 136 MΩ in vertical direction with respect to more homogeneous crystal quality in cross-sectional direction than that in vertical direction. TEM measurement was applied to evaluate the microstructure of colorless CsI:Tl crystal with different patterns of a cubic structure. Both CsI:Tl crystals show good efficiencies and good resolutions. Maintaining the same electronic conditions and amplifications, the colorless CsI:Tl scintillators represented a higher detection efficiency at 122 keV of Co-57 of 78.4 % and the energy resolution of 23.3 % compared to the detection efficiency of 75.9 % and the energy resolution of 34.6 % of the

  11. Static strain-aging in commercial purity alpha titanium

    International Nuclear Information System (INIS)

    Donoso, J.R.; Reed-Hill, R.E.

    1977-01-01

    Static strain-aging was investigated in commercial purity α-Ti, containing 0.41 at. percent of oxygen as the principal interstitial impurity. 17 μM grain size specimens, prestrained to 0.02 strain at a nominal strain-rate of 3.3 x 10 -4 s -1 , were aged in situ between 555 and 630 0 K for lengths of time between 150 and 2.55 x 10 5 seconds. Both the upper and lower yield point increments were employed as measures of the aging progress. Under the stated conditions, the static strain-aging response of the titanium appeared to consist of four stages, of which only Stages 1 and 2 were considered in this work. Stage 1 corresponded to a Haasen and Kelly type of yield point, while Stage 2, after correcting for the time-independent yield point increment of Stage 1, conformed to Cottrell aging, i.e., the increase in flow stress after aging followed a t/sup 2 / 3 / behavior. The activation energy deduced for the process is in good agreement with that for the diffusion of oxygen in titanium

  12. Structural biomechanics determine spectral purity of bush-cricket calls.

    Science.gov (United States)

    Chivers, Benedict D; Jonsson, Thorin; Soulsbury, Carl D; Montealegre-Z, Fernando

    2017-11-01

    Bush-crickets (Orthoptera: Tettigoniidae) generate sound using tegminal stridulation. Signalling effectiveness is affected by the widely varying acoustic parameters of temporal pattern, frequency and spectral purity (tonality). During stridulation, frequency multiplication occurs as a scraper on one wing scrapes across a file of sclerotized teeth on the other. The frequency with which these tooth-scraper interactions occur, along with radiating wing cell resonant properties, dictates both frequency and tonality in the call. Bush-cricket species produce calls ranging from resonant, tonal calls through to non-resonant, broadband signals. The differences are believed to result from differences in file tooth arrangement and wing radiators, but a systematic test of the structural causes of broadband or tonal calls is lacking. Using phylogenetically controlled structural equation models, we show that parameters of file tooth density and file length are the best-fitting predictors of tonality across 40 bush-cricket species. Features of file morphology constrain the production of spectrally pure signals, but systematic distribution of teeth alone does not explain pure-tone sound production in this family. © 2017 The Authors.

  13. Power and Purity: Nature as Resource in a Troubled Society

    Directory of Open Access Journals (Sweden)

    Gremaud, Ann-Sofie

    2014-11-01

    Full Text Available This article analyses representations of nature as brand and resource in current Icelandic society. This is done through an interdisciplinary approach consisting of concepts from the discipline of cultural geography and the analytical methodologies of visual cultural, imagology, discourse and brand analysis used to highlight key narratives in images and written sources. The article discusses how ideas of purity are used in branding strategies and what they mean in Iceland today e.g. as a part of the emerging regional consciousness of ‘Arctic Iceland.’ The current overlapping crises of the economy, the environment and the collective self-image in Iceland have fostered critical representations of the past, present and future of the relationship between humans and the environment. Thus utilitarian environmental policies and shallow ecology is treated critically in contemporary Icelandic art, as is the question of what constitutes pollution. Such internal conflicts of interest are analysed to show critical perspectives on the dominant narratives about Icelandic nature and society that are communicated to the outside world through nation branding.

  14. Inclusion of Solar Elevation Angle in Land Surface Albedo Parameterization Over Bare Soil Surface.

    Science.gov (United States)

    Zheng, Zhiyuan; Wei, Zhigang; Wen, Zhiping; Dong, Wenjie; Li, Zhenchao; Wen, Xiaohang; Zhu, Xian; Ji, Dong; Chen, Chen; Yan, Dongdong

    2017-12-01

    Land surface albedo is a significant parameter for maintaining a balance in surface energy. It is also an important parameter of bare soil surface albedo for developing land surface process models that accurately reflect diurnal variation characteristics and the mechanism behind the solar spectral radiation albedo on bare soil surfaces and for understanding the relationships between climate factors and spectral radiation albedo. Using a data set of field observations, we conducted experiments to analyze the variation characteristics of land surface solar spectral radiation and the corresponding albedo over a typical Gobi bare soil underlying surface and to investigate the relationships between the land surface solar spectral radiation albedo, solar elevation angle, and soil moisture. Based on both solar elevation angle and soil moisture measurements simultaneously, we propose a new two-factor parameterization scheme for spectral radiation albedo over bare soil underlying surfaces. The results of numerical simulation experiments show that the new parameterization scheme can more accurately depict the diurnal variation characteristics of bare soil surface albedo than the previous schemes. Solar elevation angle is one of the most important factors for parameterizing bare soil surface albedo and must be considered in the parameterization scheme, especially in arid and semiarid areas with low soil moisture content. This study reveals the characteristics and mechanism of the diurnal variation of bare soil surface solar spectral radiation albedo and is helpful in developing land surface process models, weather models, and climate models.

  15. Use of Aquaporins to Achieve Needed Water Purity On ISS for the EMU Space Suit System

    Science.gov (United States)

    Hill, Terry; Taylor ,Brandon W.

    2012-01-01

    Use of Aquaporins to Achieve Needed Water Purity On ISS for the EMU Space Suit System. With the U.S. Space Shuttle fleet retired, the supply of extremely high-quality water "super-Q" - required for the EMU Space suit cooling on this ISS - will become a significant operational hardware challenge in the very near future. A proposed potential solution is the use of a filtration system consisting of a semi-permeable membrane embedded with aquaporin proteins. Aquaporins are a special class of trans-membrane proteins that facilitate passive transport of water and other substances across a membrane. The specificity of these proteins is such that only water is allowed through the protein structure, and this novel property invites their adaptation for use in water filtration systems, specifically usage on the ISS for the EMU space suit system. These proteins are found in many living systems and have been developed for commercial use today.

  16. 7 CFR 201.51a - Special procedures for purity analysis.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Special procedures for purity analysis. 201.51a Section 201.51a Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Purity...

  17. Animal Sex: Purity Education and the Naturalization of the Abstinence Agenda

    Science.gov (United States)

    Sethna, Christabelle

    2010-01-01

    An early-twentieth-century movement for social purity in England, Canada and the United States aimed to eradicate prostitution, the double standard of sexual morals and their dreaded corollary, the venereal diseases. Social purists suggested that "purity education" for children was the best pedagogical prophylaxis against such…

  18. The effect of the purity and of the materials used for adapters on the purification of yttrium by solid state electrotransport

    International Nuclear Information System (INIS)

    Nikoforova, T.V.; Volkov, V.T.

    1986-01-01

    The influence of tantalum, molybdenum and zirconium adapters on the efficiency of the solid state electrotransport process is investigated with a view to increasing the quality and purity of yttrium. The degree and direction of metallic impurity electromigration in the given metals were studied. The impurities in question were shown to move in different directions depending on the type of adapter. Recommendations for the application of adapters according to their purity are given. The application of high purity tantalum as anode and cathode adapters in three-stage solid state electrotransport enabled us to obtain yttrium single crystals with a ratio of resistance at room temperature to that at helium temperatures of 1200. (orig.)

  19. The Debye light scattering equation’s scaling relation reveals the purity of synthetic dendrimers

    International Nuclear Information System (INIS)

    Tseng, Hui-Yu; Chen, Hsiao-Ping; Tang, Yi-Hsuan; Chen, Hui-Ting; Kao, Chai-Lin; Wang, Shau-Chun

    2016-01-01

    Spherical dendrimer structures cannot be structurally modeled using conventional polymer models of random coil or rod-like configurations during the calibration of the static light scattering (LS) detectors used to determine the molecular weight (M.W.) of a dendrimer or directly assess the purity of a synthetic compound. In this paper, we used the Debye equation-based scaling relation, which predicts that the static LS intensity per unit concentration is linearly proportional to the M.W. of a synthetic dendrimer in a dilute solution, as a tool to examine the purity of high-generational compounds and to monitor the progress of dendrimer preparations. Without using expensive equipment, such as nuclear magnetic resonance or mass spectrometry, this method only required an affordable flow injection set-up with an LS detector. Solutions of the purified dendrimers, including the poly(amidoamine) (PAMAM) dendrimer and its fourth to seventh generation pyridine derivatives with size range of 5–9 nm, were used to establish the scaling relation with high linearity. The use of artificially impure mixtures of six or seven generations revealed significant deviations from linearity. The raw synthesized products of the pyridine-modified PAMAM dendrimer, which included incompletely reacted dendrimers, were also examined to gauge the reaction progress. As a reaction toward a particular generational derivative of the PAMAM dendrimers proceeded over time, deviations from the linear scaling relation decreased. The difference between the polydispersity index of the incompletely converted products and that of the pure compounds was only about 0.01. The use of the Debye equation-based scaling relation, therefore, is much more useful than the polydispersity index for monitoring conversion processes toward an indicated functionality number in a given preparation.Graphical abstract

  20. The Debye light scattering equation’s scaling relation reveals the purity of synthetic dendrimers

    Energy Technology Data Exchange (ETDEWEB)

    Tseng, Hui-Yu; Chen, Hsiao-Ping [National Chung Cheng University, Department of Chemistry and Biochemistry (China); Tang, Yi-Hsuan [Kaohsiung Medical University, Department of Medicinal and Applied Chemistry (China); Chen, Hui-Ting [Kaohsiung Medical University, Department of Fragrance and Cosmetic Science (China); Kao, Chai-Lin, E-mail: clkao@kmu.edu.tw [Kaohsiung Medical University, Department of Medicinal and Applied Chemistry (China); Wang, Shau-Chun, E-mail: chescw@ccu.edu.tw [National Chung Cheng University, Department of Chemistry and Biochemistry (China)

    2016-03-15

    Spherical dendrimer structures cannot be structurally modeled using conventional polymer models of random coil or rod-like configurations during the calibration of the static light scattering (LS) detectors used to determine the molecular weight (M.W.) of a dendrimer or directly assess the purity of a synthetic compound. In this paper, we used the Debye equation-based scaling relation, which predicts that the static LS intensity per unit concentration is linearly proportional to the M.W. of a synthetic dendrimer in a dilute solution, as a tool to examine the purity of high-generational compounds and to monitor the progress of dendrimer preparations. Without using expensive equipment, such as nuclear magnetic resonance or mass spectrometry, this method only required an affordable flow injection set-up with an LS detector. Solutions of the purified dendrimers, including the poly(amidoamine) (PAMAM) dendrimer and its fourth to seventh generation pyridine derivatives with size range of 5–9 nm, were used to establish the scaling relation with high linearity. The use of artificially impure mixtures of six or seven generations revealed significant deviations from linearity. The raw synthesized products of the pyridine-modified PAMAM dendrimer, which included incompletely reacted dendrimers, were also examined to gauge the reaction progress. As a reaction toward a particular generational derivative of the PAMAM dendrimers proceeded over time, deviations from the linear scaling relation decreased. The difference between the polydispersity index of the incompletely converted products and that of the pure compounds was only about 0.01. The use of the Debye equation-based scaling relation, therefore, is much more useful than the polydispersity index for monitoring conversion processes toward an indicated functionality number in a given preparation.Graphical abstract.

  1. Isoelectric focusing purity criteria and 1H NMR detectable spectroscopic heterogeneity in the major isolated monomer hemoglobins from Glycera dibranchiata

    International Nuclear Information System (INIS)

    Constantinidis, I.; Satterlee, J.D.

    1987-01-01

    Three major monomeric hemoglobins have been isolated from the erythrocytes of Glycera dibranchiata. Their importance to structure-function studies of heme proteins lies in the fact that they have been shown to possess an exceptional amino acid substitution. In these proteins, the E-7 position is occupied by leucine rather than the more common distal histidine. This substitution alters the polarity of the heme ligand binding environment compared to myoglobin. Due to this, the G. dibranchiata monomer hemoglobins are attracting much attention. However, until now no purity criterion has been developed. Here the authors demonstrate that, for all of the Glycera momomer hemoglobins, multiple line patterns are shown on high-voltage isoelectric focusing (IEF) gels. Most of these lines are shown to be a consequence of heme-related phenomena and can be understood on the basis of changes in oxidation and ligation state of the heme iron. The multiple line pattern does not indicate significant impurities in the monomer hemoglobin preparation. The multiple line patterns on IEF gels disappear when gels of the apoproteins alone are focused. Single bands occur in this case for all of the monomer hemoglobins except component II, which displays two bands, one major and one minor. The minor band is found to be a modified apoprotein form. It is sensitive to apoprotein handling prior to focusing and depends upon whether the IEF gel is prefocused or not. From this analysis, IEF is shown to be a valuable purity criterion, and the purity of our monomer hemoglobin component II preparation is 97% one globin. The NMR results show that two types of spectroscopic heterogeneity are also present in component II, and these are unrelated to the protein purity

  2. Delayed colon perforation after palliative treatment for rectal carcinoma with bare rectal stent: a case report

    International Nuclear Information System (INIS)

    Han, Young Min; Lee, Jeong Min; Lee, Tae Hoon

    2000-01-01

    In order to relieve mechanical obstruction caused by rectal carcinoma, a bare rectal stent was inserted in the sigmoid colon of a 70-year-old female. The procedure was successful, and for one month the patient made good progress. She then complained of abdominal pain, however, and plain radiographs of the chest and abdomen revealed the presence of free gas in the subdiaphragmatic area. Surgical findings showed that a spur at the proximal end of the bare rectal stent had penetrated the rectal mucosal wall. After placing a bare rectal stent for the palliative treatment of colorectal carcinoma, close follow-up to detect possible perforation of the bowel wall is necessary

  3. Bare pomeron in perturbative QCD and small x behavior of gluon distributions

    International Nuclear Information System (INIS)

    Collins, J.C.

    1989-01-01

    The solution of the integral equation describing the bare pomeron in perturbative QCD with asymptotic freedom corrections taken into account is studied. Upper and lower bounds for the bare pomeron intercept are obtained in terms of the QCD coupling constant at some large scale. The intercept is substantially above unity. After the connection with the operator product expansion is discussed, it is shown that the behavior of parton distribution functions at small x is governed by the intercept of the bare pomeron. Thus they are steeper than 1/x by a power of x. (orig.)

  4. Radiolabeling, quality control and radiochemical purity assessment of {sup 99m}Tc-HYNIC-TOC

    Energy Technology Data Exchange (ETDEWEB)

    Melero, Laura T.U.H.; Araujo, Elaine B.; Mengatti, Jair [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    Somatostatine receptors are widely expressed by several tumors, especially of the neuroendocrine origin. In vivo images of these tumors using radiolabeled somatostatine analogues became a useful clinical tool in oncology. The aim of this work was the radiolabeling of the somatostatine analogue HYNIC-TOC with 99mTc as well as the evaluation of the radiochemical stability and quality control of labeled complex. 99mTc-HYNIC-TOC was produced by labeling conditions using 20 {mu}g of peptide, 20 mg of tricine and 10 mg of EDDA as coligands, 1110 MBq of 99mTc (99Mo-99mTc IPEN-TEC generator) and 15 {mu}g of SnCl{sub 2}.2H{sub 2}O. The reaction proceeds for 10 minutes at boiling water bath. Radiochemical purity of labeled preparation was evaluated by different chromatographic systems: ITLC-SG in methanol:ammonium acetate (1:1); TLC-SG in sodium citrate buffer 0.1 N pH 5.0 and methylethylketone, and HPLC employing column C-18, 5 {mu}m, 4.6 mm x 250 mm, UV (220 nm), radioactivity detectors, 1 mL/minute flow of acetonitrile and trifluoroacetic acid solution 0.1 %. Labeled compound has been found radiochemically stable for 5 hours and radiochemical purity was higher than 90 %. The thin layer chromatographic systems enabled the separation of radiochemical species presented in the labeled mixture as well as HPLC system. The labeling procedure studied resulted in high radiochemical yield and easy preparation. Future works include the preparation of a lyophilized reagent to make feasible the preparation of 99mTc-HYNIC-TOC at nuclear medicine services in order to study the clinical potential of the radiopharmaceutical in diagnostic and staging of neuroendocrine tumors. (author)

  5. Development of anabolic-androgenic steroids purity certified reference materials for anti-doping.

    Science.gov (United States)

    Quan, Can; Su, Fuhai; Wang, Haifeng; Li, Hongmei

    2011-12-20

    The need for certified reference materials (CRM) of anabolic-androgenic steroids reference materials was emphasized by the Beijing 2008 Olympic game as a tool to improve comparability, ensuring accuracy and traceability of analytical results for competing athletes. The China National Institute of Metrology (NIM) responded to the state request by providing seven anabolic-androgenic steroids (AAS) reference materials for Beijing Olympic anti-doping, GBW (E) 100086-GBW (E) 100092. This work describes the production of the series of AAS CRMs, according to ISO Guides 34 and 35 [1,2], which comprises the material processing, homogeneity and stability assessment, CRMs' characterization including moisture content, trace metal content. The AASs' purity values were assigned with collaborative study involved eight laboratories applying high resolution liquid chromatography-diode array detector (HPLC-DAD). Homogeneity of the AAS CRMs were determined by an in-house validated liquid chromatographic methodology. Potential degradation during storage was also investigated and a shelf-life based on this value was established. The certified values of CRMs were 99.76±0.079%, 99.76±0.25%, 99.63±0.09%, 99.67±0.11%, 98.82±0.56%, 96.30±0.39% and 99.71±0.49% (purity±expanded uncertainty with confidence level of 95%) for methyltestosterone, testosterone propionate, nandrolone, nandrolone 17-propionate, boldenone, trenbolone acetate and testosterone respectively. The certified values for all the studied AAS reference materials are traceable to the international system of units (SI). The CRMs developed were applied by 32 laboratory including sports organizations and analytical laboratories during the 2008 Olympic game for anti-doping control. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Isolation and enrichment of Cryptosporidium DNA and verification of DNA purity for whole-genome sequencing.

    Science.gov (United States)

    Guo, Yaqiong; Li, Na; Lysén, Colleen; Frace, Michael; Tang, Kevin; Sammons, Scott; Roellig, Dawn M; Feng, Yaoyu; Xiao, Lihua

    2015-02-01

    Whole-genome sequencing of Cryptosporidium spp. is hampered by difficulties in obtaining sufficient, highly pure genomic DNA from clinical specimens. In this study, we developed procedures for the isolation and enrichment of Cryptosporidium genomic DNA from fecal specimens and verification of DNA purity for whole-genome sequencing. The isolation and enrichment of genomic DNA were achieved by a combination of three oocyst purification steps and whole-genome amplification (WGA) of DNA from purified oocysts. Quantitative PCR (qPCR) analysis of WGA products was used as an initial quality assessment of amplified genomic DNA. The purity of WGA products was assessed by Sanger sequencing of cloned products. Next-generation sequencing tools were used in final evaluations of genome coverage and of the extent of contamination. Altogether, 24 fecal specimens of Cryptosporidium parvum, C. hominis, C. andersoni, C. ubiquitum, C. tyzzeri, and Cryptosporidium chipmunk genotype I were processed with the procedures. As expected, WGA products with low (sequences in Sanger sequencing. The cloning-sequencing analysis, however, showed significant contamination in 5 WGA products (proportion of positive colonies derived from Cryptosporidium genomic DNA, ≤25%). Following this strategy, 20 WGA products from six Cryptosporidium species or genotypes with low (mostly sequencing, generating sequence data covering 94.5% to 99.7% of Cryptosporidium genomes, with mostly minor contamination from bacterial, fungal, and host DNA. These results suggest that the described strategy can be used effectively for the isolation and enrichment of Cryptosporidium DNA from fecal specimens for whole-genome sequencing. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  7. Radiolabeling, quality control and radiochemical purity assessment of 99mTc-HYNIC-TOC

    International Nuclear Information System (INIS)

    Melero, Laura T.U.H.; Araujo, Elaine B.; Mengatti, Jair

    2009-01-01

    Somatostatine receptors are widely expressed by several tumors, especially of the neuroendocrine origin. In vivo images of these tumors using radiolabeled somatostatine analogues became a useful clinical tool in oncology. The aim of this work was the radiolabeling of the somatostatine analogue HYNIC-TOC with 99mTc as well as the evaluation of the radiochemical stability and quality control of labeled complex. 99mTc-HYNIC-TOC was produced by labeling conditions using 20 μg of peptide, 20 mg of tricine and 10 mg of EDDA as coligands, 1110 MBq of 99mTc (99Mo-99mTc IPEN-TEC generator) and 15 μg of SnCl 2 .2H 2 O. The reaction proceeds for 10 minutes at boiling water bath. Radiochemical purity of labeled preparation was evaluated by different chromatographic systems: ITLC-SG in methanol:ammonium acetate (1:1); TLC-SG in sodium citrate buffer 0.1 N pH 5.0 and methylethylketone, and HPLC employing column C-18, 5 μm, 4.6 mm x 250 mm, UV (220 nm), radioactivity detectors, 1 mL/minute flow of acetonitrile and trifluoroacetic acid solution 0.1 %. Labeled compound has been found radiochemically stable for 5 hours and radiochemical purity was higher than 90 %. The thin layer chromatographic systems enabled the separation of radiochemical species presented in the labeled mixture as well as HPLC system. The labeling procedure studied resulted in high radiochemical yield and easy preparation. Future works include the preparation of a lyophilized reagent to make feasible the preparation of 99mTc-HYNIC-TOC at nuclear medicine services in order to study the clinical potential of the radiopharmaceutical in diagnostic and staging of neuroendocrine tumors. (author)

  8. Assessing the adequacy of the bare optical potential in near-barrier fusion calculation

    International Nuclear Information System (INIS)

    Canto, L.F.; Gomes, P.R.S.; Lubian, J.; Hussein, M.S.; Lotti, P.

    2014-01-01

    We critically examine the differences among the different bare nuclear interactions used in near-barrier heavy-ion fusion analysis and coupled-channels calculations, and discuss the possibility of extracting the barrier parameters of the bare potential from above-barrier data. We show that the choice of the bare potential may be critical for the analysis of the fusion cross sections. Although this may seem trivial, several recent papers use different bare potentials and reach different conclusions, especially when weakly bound systems are considered and possible relatively small fusion cross section enhancements or suppressions are found. We show also that the barrier parameters taken from above-barrier data may be very wrong. (orig.)

  9. Exit-channel distorting potentials in heavy-ion inelastic scattering and equivalent bare optical potential

    International Nuclear Information System (INIS)

    Kubo, K.-I.; Hodgson, P.E.

    1981-01-01

    The effect of distorting potentials on transitions in the heavy-ion inelastic 16 O on 40 Ca reaction at 60 MeV has been investigated using the DWBA approximation. The polarization potential due to the nuclear and Coulomb excitations was calculated based on the plane wave assumption and the bare imaginary potential calculated by subtracting the polarization potential from the elastic optical potential. The bare potential was found to compare well with a phenomenological channel-coupling calculation. This bare potential was used for the DWBA calculation and the result found to be quite consistent with those obtained by the exact channel-coupling calculation. The shape of the bare potential compared with the elastic optical imaginary potential is discussed with reference to those of the nuclear plus Coulomb excitation contributions and the nuclear-Coulomb cross term, which interfere destructively. (U.K.)

  10. Potentiality, Sovereignty and Bare Life A Critical Reading of Giorgio Agamben

    Directory of Open Access Journals (Sweden)

    German Eduardo Primera Villamizar

    2014-12-01

    Full Text Available This article presents a critical account of Agamben’s understanding of the logic of sovereignty and of the notion bare life, particularly Agamben’s approach to the paradox of sovereignty and its relation to Aristotle’s metaphysical category of potentiality. With regards to bare life, it brings together an analysis of the figure of the homo sacer with an account of Agamben’s use of paradigms as methodological tools. The first part of the paper argues that Agamben ontologises sovereignty by dramatising the paradox of its structure as im-potentiality. The second part claims that even though an account of Agamben’s methodology serves to respond to the different critiques that his notion of bare life has raised, Agamben’s notions of sovereignty and of bare life ultimately rely on Schmitt’s decisionism.

  11. Assessing the adequacy of the bare optical potential in near-barrier fusion calculation

    Energy Technology Data Exchange (ETDEWEB)

    Canto, L.F. [Universidade Federal do Rio de Janeiro, Instituto de Fisica, CP 68528, Rio de Janeiro (Brazil); Gomes, P.R.S.; Lubian, J. [Universidade Federal Fluminense, Instituto de Fisica, Niteroi, R.J. (Brazil); Hussein, M.S. [Universidade de Sao Paulo, Instituto de Estudos Avancados, C. P. 72012, Sao Paulo-SP (Brazil); Universidade de Sao Paulo, Instituto de Fisica, C. P. 66318, Sao Paulo (Brazil); Lotti, P. [INFN, Padova (Italy)

    2014-05-15

    We critically examine the differences among the different bare nuclear interactions used in near-barrier heavy-ion fusion analysis and coupled-channels calculations, and discuss the possibility of extracting the barrier parameters of the bare potential from above-barrier data. We show that the choice of the bare potential may be critical for the analysis of the fusion cross sections. Although this may seem trivial, several recent papers use different bare potentials and reach different conclusions, especially when weakly bound systems are considered and possible relatively small fusion cross section enhancements or suppressions are found. We show also that the barrier parameters taken from above-barrier data may be very wrong. (orig.)

  12. J-plane structure of the 'cylinder'; slope and intercept of the bare pomeron

    International Nuclear Information System (INIS)

    Bishari, M.

    1975-01-01

    An integral equation is derived and investigated for the 'cylinder' with full t-dependence. In contrast to the pure pole planar model, the 'cylinder' contains, in addition to the bare pomeron pole, also a Reggeon-Reggeon cut. The strongly correlated slope and intercept of the bare pomeron have the correct observed values. Brief comments are made on the concept of 'asymptotic planarity'. (Auth.)

  13. Contribution of the low cycle fatigue on ultra high purity Ni-Cr-Fe alloys and on Ni monocrystals to the understanding of the hydrogen role in stress corrosion cracking for the alloys 600 and 690; Apport de la fatigue oligocyclique sur alliages Ni-Cr-Fe d'ultra haute purete et sur monocristaux de Ni a la comprehension sous contrainte des alliages 600 et 69O

    Energy Technology Data Exchange (ETDEWEB)

    Renaudot, N

    1999-06-01

    We discuss the role of hydrogen in cracking of Ni base alloys used for pressurised water reactor (PWR) primary tubes (alloy 600 and 690). Cracking can be explained by a Stress Corrosion Cracking (SCC) phenomenon. For this purpose, Low cycle fatigue (R = - 1) under cathodic charging at room temperature is conducted to study hydrogen effects on propagation of cracks mechanically initiated by the formation of Persistent Slip Bands (PSB). Low cycle fatigue on Ultra High Purity specimens (Ni, alloy 600 and 690) reveals the very important hydrogen effect on crack propagation rate, whatever the Cr content in the Ni base alloy. If Cr seems to have an effect over-hydrogen penetration in specimens (by a protective film formation), it have no beneficial effect when hydrogen have diffused ahead of a crack tip. Propagation rates (transgranular or intergranular) are highly increased, no matter of the absence of impurities like sulphur. Then, in PWR, the difference in the behaviour of alloy 600 and 690 could be due to a slower microcrack propagation rate for alloy 690. Protective films could play an important role in this difference, which is to study. Low cycle fatigue on Ni single crystals oriented for single slip shows, for the first time on bulk specimen, a macroscopic softening which can be explained. by hydrogen-dislocation interactions. Moreover, a simple quantitative model based on these interactions results in the same softening as the one observed experimentally. These results allow to validate experimentally one of the most important steps in the 'Corrosion Enhanced Plasticity (CEP) model', i.e. the softening ahead of a stress corrosion crack tip by hydrogen dislocation interactions. This is of importance because this model can explain cracking in numerous FCC materials-environment couple. (author)

  14. EAARL Coastal Topography-Assateague Island National Seashore, 2008: Bare Earth

    Science.gov (United States)

    Bonisteel, Jamie M.; Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Stevens, Sara; Yates, Xan; Klipp, Emily S.

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived bare-earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Northeast Coastal and Barrier Network, Kingston, RI; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Assateague Island National Seashore in Maryland and Virginia, acquired March 24-25, 2008. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL) was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the

  15. Radioactive preparations. Determination of radiochemical purity by thin-layer chromatography

    International Nuclear Information System (INIS)

    1986-01-01

    The standard sets the data which must be attached to every sample, and the equipment, chemicals and auxiliary substances used in the determination of radiochemical purity of substances by chromatography. Described are preparation of the sample, the procedure of sample deposition, the development, drying and detection of the radioactive preparation. The qualitative and quantitative assessment of the radiochromatogram is described as are the calculation of radiochemical purity and the determination of the reproducibility of measurement of radiochemical purity of radioactive preparations. (E.S.)

  16. A Point Kinetics Model for Estimating Neutron Multiplication of Bare Uranium Metal in Tagged Neutron Measurements

    Science.gov (United States)

    Tweardy, Matthew C.; McConchie, Seth; Hayward, Jason P.

    2017-07-01

    An extension of the point kinetics model is developed to describe the neutron multiplicity response of a bare uranium object under interrogation by an associated particle imaging deuterium-tritium (D-T) measurement system. This extended model is used to estimate the total neutron multiplication of the uranium. Both MCNPX-PoliMi simulations and data from active interrogation measurements of highly enriched and depleted uranium geometries are used to evaluate the potential of this method and to identify the sources of systematic error. The detection efficiency correction for measured coincidence response is identified as a large source of systematic error. If the detection process is not considered, results suggest that the method can estimate total multiplication to within 13% of the simulated value. Values for multiplicity constants in the point kinetics equations are sensitive to enrichment due to (n, xn) interactions by D-T neutrons and can introduce another significant source of systematic bias. This can theoretically be corrected if isotopic composition is known a priori. The spatial dependence of multiplication is also suspected of introducing further systematic bias for high multiplication uranium objects.

  17. Purity and Defect Characterization of Single-Wall Carbon Nanotubes Using Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    Yasumitsu Miyata

    2011-01-01

    Full Text Available We investigated the purity and defects of single-wall carbon nanotubes (SWCNTs produced by various synthetic methods including chemical vapor deposition, arc discharge, and laser ablation. The SWCNT samples were characterized using scanning electron microscopy (SEM, thermogravimetric analysis (TGA, and Raman spectroscopy. Quantitative analysis of SEM images suggested that the G-band Raman intensity serves as an index for the purity. By contrast, the intensity ratio of G-band to D-band (G/D ratio reflects both the purity and the defect density of SWCNTs. The combination of G-band intensity and G/D ratio is useful for a quick, nondestructive evaluation of the purity and defect density of a SWCNT sample.

  18. [Research on determination of chemical purity of andrographolide by coulometric titration method].

    Science.gov (United States)

    Yang, Ning; Yang, Dezhi; Xu, Lishen; Lv, Yang

    2010-04-01

    The determination of chemical purity of andrographolide by coulometric titration method is studied in this paper. The coulometric titration was carried out in a mixture composed of 4 mol x L(-1) hydrochloric acid and 1 mol x L(-1) potassium bromide solution and 1 mol x L(-1) potassium nitrate solution (1:1). Bromine is electrogenerated at the anode and reacts with the andrographolide. The number of electrons involved in the eleatrode reaction is 2. Purity of andrographolide is 99.76% compared with 99.77% utilizing area normalization method by HPLC. The RSD are 0.33% and 0.02% respectively. The results from two methods are consistent, so the determination of chemical purity of andrographolide by coulometric titration method is scientific and feasible. The method is rapid, simple, convenient, sensitive and accurate. The reference material is not essential in the method. The method is suitable for determination of chemical purity of andrographolide.

  19. Directly Grafting Alkanethiol on Bare Si (111) by UV-assisted Photochemical Reaction

    Science.gov (United States)

    Chang, Lo-Yueh; Shiu, Hung-Wei; Gwo, Shangjr; Chen, Chia-Hao

    2014-03-01

    Self-assembled monolayers (SAMs) are organic molecules that self-assembled and closely packed on substrate surface. The surface physic and chemical properties are dependent on the controllable tail of SAMs. Therefore, SAMs is attracting a lot of attention in bio-sensing, nano-manipulating, and microfluidic field. The alkanethiol on noble metal surface, such as gold and silver, is a well-known SAM system to understand the fundamental properties. However, alkanethiols grown on semiconductor surfaces was less systematically studied, especially on bare silicon surface, despite their prospective applications. To have in-depth understanding of such system, we tried to grow alkanethiol SAMs on hydrogen-terminated Si surface by UV-assisted photochemical reaction. The resulting monolayer was studied by means of water contact angle measurement, synchrotron radiation based X-ray photoemission spectroscopy, and polarization dependent near-edge X-ray absorption fine structure. The combined characterization probes revealed a hydrophobic ambient surface, and the n-alkanethiols were directly attached on Si through Si-S bond that formed a highly order monolayer to prevent the air oxidation and contamination.

  20. MCP detector read out with a bare quad Timepix at kilohertz frame rates

    International Nuclear Information System (INIS)

    Vallerga, J; Tremsin, A; McPhate, J; Siegmund, O; Raffanti, R

    2011-01-01

    The existing Berkeley neutron sensitive MCP/Timepix hybrid detector has been very successful at demonstrating energy resolved spatial imaging with a single Timepix ASIC read out at a ∼ 30 Hz frame rate where each neutron's position and time (energy) is determined (X,Y,E). By increasing the detector format using a quad arrangement of Timepix readouts and increasing the frame rate to 1 kHz, we can increase our total event throughput by a factor of 120, thereby taking full advantage of the high fluxes of modern pulsed neutron sources (10 6 n cm -2 s -1 ). The key to this conversion is a new design for the ASIC readout, called the Berkeley Quad Timepix detector, consisting of 3 major subsystems. The first is a quad (2 x 2) bare Timepix ASIC board mounted directly behind the neutron sensitive MCPs in a hermetic vacuum enclosure with a sapphire window. The data from the Timepix ASICs flow to the second subsystem called the Interface board whose field programmable gate array (FPGA) rearranges and converts the digital bit stream to LVDS logic levels before sending downstream to the third subsystem, the Roach board. The Roach board is also FPGA based, and takes the data from all the ASICs and analyses the frames to extract information on the input events to pass on to the host PC. This paper describes in detail the hardware and firmware designs to accomplish this task.

  1. Voltammetric determination of caffeine in beverage samples on bare boron-doped diamond electrode.

    Science.gov (United States)

    Svorc, L'ubomír; Tomčík, Peter; Svítková, Jana; Rievaj, Miroslav; Bustin, Dušan

    2012-12-01

    A sensitive and selective electrochemical method for the caffeine determination using bare boron-doped diamond electrode was developed. It was found that caffeine provided highly reproducible and well-defined irreversible oxidation peak at very positive potential. The effects of supporting electrolyte, pH and scan rate on the voltammetric response of caffeine oxidation were studied to select the optimum experimental conditions. Linear response of peak current on the concentration in the range from 4×10(-7) to 2.5×10(-5)M, good repeatability (RSD of 2.1%) and detection limit of 1.5×10(-7)M without any chemical modifications and electrochemical surface pretreatment were evaluated. The effect of possible interferents appeared to be negligible which evidently proved very good selectivity. The proposed method was successfully applied for the caffeine determination in commercially available beverage samples, with results in a close statistical agreement to those declared by manufacturer and HPLC used as independent method. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Antibiotic purification from fermentation broths by counter-current chromatography: analysis of product purity and yield trade-offs.

    Science.gov (United States)

    Booth, A J; Ngiam, S H; Lye, G J

    2004-12-01

    Counter-current chromatography (CCC) is a low pressure, liquid-liquid chromatographic technique which has proven to be a powerful purification tool for the high-resolution fractionation of a variety of active pharmaceutical compounds. The successful integration of CCC into either existing or new manufacturing processes requires the predictable purification of target compounds from crude, fermentation-derived, feed streams. This work examines the feasibility of CCC for the purification of fermentation-derived erythromycin A (EA) from its structurally and chemically similar analogues. At the laboratory scale, the effect of feed pre-treatment using either clarified, forward extracted (butyl acetate) or back extracted broth on EA separation was investigated. This defined the degree of impurity removal required, i.e. back extracted broth, to ensure a reproducible elution profile of EA during CCC. Optimisation and scale-up of the separation studied the effects of mobile phase flow (2-40 ml.min(-1)) and solute loading (0.1-10 g) on the attainable EA purity and yield. The results in all cases demonstrated a high attainable EA purity (>97% w/w) with throughputs up to 0.33 kg.day(-1). Secondly, a predictive scale-up model was applied demonstrating, that from knowledge of the solute distribution ratio of EA (K(EA)) at the laboratory scale, the EA elution time at the pilot scale could be predicted to within 3-10%, depending upon the solute injection volume. In addition, this study has evaluated a "fractionation diagram" approach to visually determine the effects of key operational variables on separation performance. This resulted in accurate fraction cut-point determination for a required degree of product purity and yield. Overall, the results show CCC to be a predictable and scaleable separation technique capable of handling real feed streams.

  3. Location of Bare Soil Surface and Soil Line on the RED-NIR Spectral Plane

    Science.gov (United States)

    Koroleva, P. V.; Rukhovich, D. I.; Rukhovich, A. D.; Rukhovich, D. D.; Kulyanitsa, A. L.; Trubnikov, A. V.; Kalinina, N. V.; Simakova, M. S.

    2017-12-01

    Soil as a separate natural body occupies certain area with its own set of spectral characteristics within the RED-NIR spectral space. This is an ellipse-shaped area, and its semi-major axis is the soil line for a satellite image. The spectral area for a bare soil surface is neighboring to the areas of black carbon, straw, vegetating plants, and missing RED-NIR values. A reliable separation of the bare soil surface within the spectral space is possible with the technology of spectral neighborhood of soil line. The accuracy of this method is 90%. The determination of the bare soil surface using vegetation indices, both relative (NDVI), and perpendicular (PVI), is incorrect; the accuracy of these methods does not exceed 65%, and for most of the survey seasons it may be lower than 50%. The flat part of the "tasseled cap" described as the soil line, is not a synonym for the area of the bare soil surface. The bare soil surface on the RED-NIR plots occupies significantly smaller areas than the area of soil line according to Kauth and Thomas.

  4. Highly Accurate Sensor for High-Purity Oxygen Determination, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In this STTR Phase I effort, Los Gatos Research (LGR) and Professor Scott Sanders (Mechanical Engineering Department, University of Wisconsin -- Madison) propose to...

  5. Hot Ductility and High Temperature Microstructure of High Purity Iron Alloys

    OpenAIRE

    Abiko, K.

    1995-01-01

    The inherent properties of metals are affected by impurity elements, sometimes strongly. There are many brittle phenomena in iron and its alloys due to the harmful effect of trace impurities such as sulphur, phosphorus, hydrogen and so on. On the other hand, a large number of alloying elements also embrittle iron due to the transformation and precipitation of secondary phase. For example, the ductility of Fe-Cr alloy decreases with the increase in chromium content, although the strength and t...

  6. Low energy consumption method for separating gaseous mixtures and in particular for medium purity oxygen production

    Science.gov (United States)

    Jujasz, Albert J.; Burkhart, James A.; Greenberg, Ralph

    1988-01-01

    A method for the separation of gaseous mixtures such as air and for producing medium purity oxygen, comprising compressing the gaseous mixture in a first compressor to about 3.9-4.1 atmospheres pressure, passing said compressed gaseous mixture in heat exchange relationship with sub-ambient temperature gaseous nitrogen, dividing the cooled, pressurized gaseous mixture into first and second streams, introducing the first stream into the high pressure chamber of a double rectification column, separating the gaseous mixture in the rectification column into a liquid oxygen-enriched stream and a gaseous nitrogen stream and supplying the gaseous nitrogen stream for cooling the compressed gaseous mixture, removing the liquid oxygen-enriched stream from the low pressure chamber of the rectification column and pumping the liquid, oxygen-enriched steam to a predetermined pressure, cooling the second stream, condensing the cooled second stream and evaporating the oxygen-enriched stream in an evaporator-condenser, delivering the condensed second stream to the high pressure chamber of the rectification column, and heating the oxygen-enriched stream and blending the oxygen-enriched stream with a compressed blend-air stream to the desired oxygen concentration.

  7. EBSD study of purity effects during hot working in austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    El Wahabi, M. [Centre SMS, CNRS UMR 5146, Ecole Nationale Superieure des Mines de Saint-Etienne, 158, cours Fauriel-42023, Saint-Etienne Cedex 2 (France) and Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, ETSEIB, Universidad Politecnica de Cataluna, Av. Diagonal 647, Barcelona 08028 (Spain)]. E-mail: elwahabi@emse.fr; Gavard, L. [Centre SMS, CNRS UMR 5146, Ecole Nationale Superieure des Mines de Saint-Etienne, 158, cours Fauriel-42023, Saint-Etienne Cedex 2 (France); Cabrera, J.M. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, ETSEIB, Universidad Politecnica de Cataluna, Av. Diagonal 647, Barcelona 08028 (Spain); Prado, J.M. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, ETSEIB, Universidad Politecnica de Cataluna, Av. Diagonal 647, Barcelona 08028 (Spain); Montheillet, F. [Centre SMS, CNRS UMR 5146, Ecole Nationale Superieure des Mines de Saint-Etienne, 158, cours Fauriel-42023, Saint-Etienne Cedex 2 (France)

    2005-02-25

    The technique of electron back scattering diffraction (EBSD) is considered as a powerful instrument for the study of the microstructural changes during hot forming processes and gives the possibility to present the information in different ways (OIM, misorientation diagram and pole figures). The present work is focused on the observation by EBSD of the microstructure evolution during deformation at high temperature of three austenitic stainless steels: AISI-304H, AISI-304L and a high purity steel HP. The difference between the three steels is the content carbon and the presence of residual elements. To this aim compression tests were carried out at a constant strain rate of 0.001 s{sup -1} and different temperatures. The study showed an increase of twin boundary fractions and a diminution of substructure (low angle densities boundaries) at increasing temperatures. On the other hand, increasing carbon content promotes lower twin boundary fractions and larger amounts of low angle boundaries. This effect can be explained by the reduction of grain boundary mobility caused by increasing carbon contents, which in turn reduces the migration rate and consequently the probability of twin boundary generation. Moreover, the increment of low angle boundaries with carbon content accelerates the twin character loss. It was also found that the dynamically recrystallized grain size decreased at increasing carbon content due to a typical drag effect. No important features on textures were found during DDRX.

  8. A possible step to surfaces at vanishing bare coupling in quantumchromodynamics

    International Nuclear Information System (INIS)

    Schlereth, H.

    1984-01-01

    Starting from a kind of half-dualized nonabelian action it is shown that for gsub(bare) → 0 it reduces to QCD. Integrating out the variables in the reversed order leads to a dual form of QCD. This form contains a constraint which can be solved in terms of surfaces with quark boundaries. Due to the nonabelian structure these surfaces cannot be moved in space-time by singular gauge transformations as the Dirac surface. It is conjectured that they become fully dynamical by quantum effects. The nontrivial structure of the dual theory at gsub(bare) → 0 is entirely due to it being nonabelian. The presence of the surfaces breaks self-duality at gsub(bare) → 0. A lattice version of the half-dualized action is briefly discussed. (Auth.)

  9. Study on the relationship between turbulent normal stresses in the fully developed bare rod bundle flow

    International Nuclear Information System (INIS)

    Lee, Kye Bock; Lee, Byung Jin

    1995-01-01

    The turbulence structure for fully developed flow through the subchannels formed by the bare rod array depends on the pitch to rod diameter ratio. For fairly open spaced bare rod arrays, the distributions of the three components of the turbulent normal stresses are similar to those measured in circular pipe. However, for more closely spaced arrays, the turbulence structure, especially in the gap region, departs markedly from the pipe flow distribution. A linear relationship between turbulent normal stresses and turbulent kinetic energy for fully developed turbulent flow through regularly spaced bare rod arrays has been developed. This correlation can be used in connection with various theoretical analyses applied in turbulence research. 9 figs., 10 refs. (Author)

  10. Complications of transradial coronary angiography: a comparative study between using trocar needle and using bare needle

    International Nuclear Information System (INIS)

    Huang Chunyan; Wang Zhongjie; Chen Liyuan

    2010-01-01

    Objective: To analyze the advantages and disadvantages of trocar needle puncturing and bare needle puncturing in performing transradial coronary angiography through comparing the surgical successful rate and the occurrence of complications between two techniques. Methods: A total of 450 patients, who were scheduled to receive transradial coronary angiography, were enrolled in this study. The patients were randomly and equally divided into trocar needle group (n=225) and bare needle group (n=225). Transradial coronary angiography was performed in all patients, the technical success and the puncture-related complications were observed. The differences between two groups were compared and the results were statistically analyzed. Results: The successful rate of placing sheath pipe in trocar needle group and bare needle group was 98.22% (221/225) and 90.22% (203/225) respectively, the difference between two groups was statistically significant (P < 0.01). The mean time spent in puncturing in trocar needle group and bare needle group was (3.98 ± 0.54) min. and (6.13 ± 0.61) min. respectively (P < 0.01). In bare needle group the complications included radial artery spasm (4.89%, n=11), subcutaneous ecchymosis (6.67%, n=15) and local hematoma (3.56%, n=8), while in trocar group the complications included radial artery spasm (1.33%, n=3), subcutaneous ecchymosis (2.67%, n=6) and local hematoma (0.44%, n=1). Conclusion: In performing percutaneous coronary arteriography via radial arterial access the use of trocar needle is superior to the use of bare needle. Using trocar needle can reduce the operative time,increase the technical successful rate and lower the occurrence of complications. Therefore, using trocar needle to perform puncturing should be the technique of first choice. (authors)

  11. Continual erosion of bare rocks after the Wenchuan earthquake and control strategies

    Science.gov (United States)

    Wang, Zhaoyin; Shi, Wenjing; Liu, Dandan

    2011-03-01

    The newly bared rocks created by the Wenchuan earthquake are undergoing continual intensive erosion in the form of detachment and movement of individual grains. Grain erosion is defined as the phenomenon of breaking down bare rocks under the action of insolation and temperature change, detachment of grains from the rockwalls by wind, flow down of grains on the slope under the action of gravity, and accumulation of grains at the toe of the mountain, forming a deposit fan. The Wenchuan earthquake, which occurred in Sichuan on May 12, 2008, caused thousands of avalanches and landslides and left scars on slopes and a huge area of bare rocks. Grain erosion causes flying stones, injured humans and resulted in numerous slope debris flows. The process of grain erosion and strategies to limit the erosion were studied by field investigations and field experiments. According to these field investigations and field studies, the most serious grain erosion occurs in spring and early summer when it is very dry. Rocks are broken down to grains under the action of insolation and temperature change. Then, wind blows the grains from the bare rock down slope. Experimental results showed that the amount of grains blown down by wind per area of rock surface per unit time is proportional to the fourth power of the wind speed. However, the size of the grains blown down by wind increases linearly with the wind speed. An experiment proved that grain erosion can be controlled with two moss species. Moss spores were mixed with clay suspension and splashed on bare rocks. The moss species germinated on the rock surface in one month and greened the bare rocks in two months. The moss layer protected the rocks from insolation and mitigated the effects of temperature change, thus effectively mitigated grain erosion.

  12. Photoelectrochemical properties of bare fluorine doped tin oxide and its electrocatalysis and photoelectrocatalysis toward cysteine oxidation

    International Nuclear Information System (INIS)

    Mu, Shaolin; Shi, Qiaofang

    2016-01-01

    Graphical abstract: CVs of 0.30 M Na 2 SO 4 solution containing 2.0 mM cysteine, curves: (1) glassy carbon electrode, (2) FTO electrode in the dark, (3) FTO electrode in the light illumination, and (4) Pt electrode; pH 10.0, at a scan rate of 60 mV s −1 . - Highlights: • First revelation of photoelectrochemical properties of bare fluorine doped tin oxide. • Determination of band gap of energy of FTO in the solution without a redox couple. • Electrochemical and photoelectrochemical catalysis of bare FTO toward cysteine oxidation. • Determination and recognition of cysteine with electrocatalytic and photocatalytic methods. • Rate-determining step of cysteine oxidation at the FTO electrode. - Abstract: We first revealed that the bare fluorine doped tin oxide (FTO) under the cathodic polarization over −0.7 V (vs.SCE) shows very sensitive to the irradiating light in a wide wavelength region 850–400 nm in the aqueous solution free of a redox couple, and its band gap of energy E g is determined to be 1.38 eV via the photoelectrochemical method. The bare FTO can effectively catalyze electrochemically L-cysteine (CySH) oxidation and especially shows the photocatalytic ability toward CySH oxidation. Thus the bare FTO electrode can be directly used for determination of CySH concentration using cyclic voltammetry in both the dark and light illumination and it can be used to recognize CySH among 20 α-amino acids found in proteins, based on the low oxidation peak potential and unique photoelectric response. The rate-determining step for the photocatalytic oxidation of CySH on the bare FTO electrode is controlled by supply of charge inside the FTO film to the electrode surface, which exhibits the typical characteristics of semiconductors.

  13. The impact of membrane permeability and dialysate purity on cardiovascular outcomes.

    Science.gov (United States)

    Asci, Gulay; Tz, Huseyin; Ozkahya, Mehmet; Duman, Soner; Demirci, Meltem Sezis; Cirit, Mustafa; Sipahi, Savas; Dheir, Hamad; Bozkurt, Devrim; Kircelli, Fatih; Ok, Ebru Sevinc; Erten, Sinan; Ertilav, Muhittin; Kose, Timur; Basci, Ali; Raimann, Jochen G; Levin, Nathan W; Ok, Ercan

    2013-05-01

    The effects of high-flux dialysis and ultrapure dialysate on survival of hemodialysis patients are incompletely understood. We conducted a randomized controlled trial to investigate the effects of both membrane permeability and dialysate purity on cardiovascular outcomes. We randomly assigned 704 patients on three times per week hemodialysis to either high- or low-flux dialyzers and either ultrapure or standard dialysate using a two-by-two factorial design. The primary outcome was a composite of fatal and nonfatal cardiovascular events during a minimum 3 years follow-up. We did not detect statistically significant differences in the primary outcome between high- and low-flux (HR=0.73, 95% CI=0.49 to 1.08, P=0.12) and between ultrapure and standard dialysate (HR=0.90, 95% CI=0.61 to 1.32, P=0.60). Posthoc analyses suggested that cardiovascular event-free survival was significantly better in the high-flux group compared with the low-flux group for the subgroup with arteriovenous fistulas, which constituted 82% of the study population (adjusted HR=0.61, 95% CI=0.38 to 0.97, P=0.03). Furthermore, high-flux dialysis associated with a lower risk for cardiovascular events among diabetic subjects (adjusted HR=0.49, 95% CI=0.25 to 0.94, P=0.03), and ultrapure dialysate associated with a lower risk for cardiovascular events among subjects with more than 3 years of dialysis (adjusted HR=0.55, 95% CI=0.31 to 0.97, P=0.04). In conclusion, this trial did not detect a difference in cardiovascular event-free survival between flux and dialysate groups. Posthoc analyses suggest that high-flux hemodialysis may benefit patients with an arteriovenous fistula and patients with diabetes and that ultrapure dialysate may benefit patients with longer dialysis vintage.

  14. Bare Nouns in Danish with Special Reference to the Object Position

    DEFF Research Database (Denmark)

    Müller, Henrik Hoeg

    2017-01-01

    Based on a discussion of correlations between syntactic position, prosodic cues, aspect and generic vs. non-generic interpretations, this paper substantiates that Danish Bare Plural count nouns (BPs) have a wider distribution than Bare Singular count nouns (BSS). BPs, unlike BSS, can occur...... in subject position, function as both generic and existential arguments, and appear with all aspectual verb classes. However, BPs and BSS expressing a non-generic, modificational meaning concur in object position of activity verbs and stative verbs with a possession relation implicature. These V+BP and V...

  15. Determination of kinetic isotopic fractionation of water during bare soil evaporation

    Science.gov (United States)

    Quade, Maria; Brüggemann, Nicolas; Graf, Alexander; Rothfuss, Youri

    2017-04-01

    A process-based understanding of the water cycle in the atmosphere is important for improving meteorological and hydrological forecasting models. Usually only net fluxes of evapotranspiration - ET are measured, while land-surface models compute their raw components evaporation -E and transpiration -T. Isotopologues can be used as tracers to partition ET, but this requires knowledge of the isotopic kinetic fractionation factor (αK) which impacts the stable isotopic composition of water pools (e.g., soil and plant waters) during phase change and vapor transport by soil evaporation and plant transpiration. It is defined as a function of the ratio of the transport resistances in air of the less to the most abundant isotopologue. Previous studies determined αK for free evaporating water (Merlivat, 1978) or bare soil evaporation (Braud et al. 2009) at only low temporal resolution. The goal of this study is to provide estimates at higher temporal resolution. We performed a soil evaporation laboratory experiment to determine the αK by applying the Craig and Gordon (1965) model. A 0.7 m high column (0.48 m i.d.) was filled with silt loam (20.1 % sand, 14.9 % loam, 65 % silt) and saturated with water of known isotopic composition. Soil volumetric water content, temperature and the isotopic composition (δ) of the soil water vapor were measured at six different depths. At each depth microporous polypropylene tubing allowed the sampling of soil water vapor and the measurement of its δ in a non-destructive manner with high precision and accuracy as detailed in Rothfuss et al. (2013). In addition, atmospheric water vapor was sampled at seven different heights up to one meter above the surface for isotopic analysis. Results showed that soil and atmospheric δ profiles could be monitored at high temporal and vertical resolutions during the course of the experiment. αK could be calculated by using an inverse modeling approach and the Keeling (1958) plot method at high temporal

  16. Stent selection in patients with myocardial infarction: drug eluting, biodegradable polymers or bare metal stents?

    Science.gov (United States)

    Mieres, Juan; Rodríguez, Alfredo E

    2012-08-01

    Percutaneous coronary intervention (PCI) has been increasingly used in the last years during interventional procedures in patients with acute coronary syndromes (ACS) including ST elevation myocardial infarction (STEMI) and non-ST elevation myocardial infarction (NSTEMI). In patients with either STEMI, NSTEMI, high risk ACS with EKG changes or cardiac enzymes rises; PCI with bare metal stent (BMS) implantation has been associated with a significant improvement in clinical outcome. Therefore, BMS implantation during primary PCI in STEMI has become a standard of practice. With the introduction of drug eluting stents (DESs) in this decade, the use of these new devices instead of BMSs in patients with STEMI has emerged as a rational PCI alternative in this particular subgroup of patients. In spite of the unquestionable benefits of DESs in terms of reduction of restenosis and TVR, specific concerns have arisen with regard to their long-term safety. High incidence of very late stent thrombosis has been described with these devices, and special attention should be paid in patients with unstable coronary lesions, in which plaque composition and remodeling may play a main role in their safety and long-term outcome. Intraluminal thrombus caused by plaque rupture is the most frequent mechanism of STEMI, in which the necrotic core and thin fibrous cap play a major role. In this context, the use of first DESs designs may be futile or even unsafe because delayed healing may further contribute to plaque instability. Adjunctive invasive imaging tools can improve stent deployment and safety outcome in these lesions with intravascular findings of plaque instability. Recently, other players such as new dedicated antithrombotic BMS designs, including selfexpanding stents or drug-eluting coated balloons, are exploring their potential indications in patients with ACS and myocardial infarction. This paper reports and discusses new stent devices and adjunctive pharmacologic agents. It

  17. Selective Surface Charge Sign Reversal on Metallic Carbon Nanotubes for Facile Ultrahigh Purity Nanotube Sorting.

    Science.gov (United States)

    Wang, Jing; Nguyen, Tuan Dat; Cao, Qing; Wang, Yilei; Tan, Marcus Y C; Chan-Park, Mary B

    2016-03-22

    Semiconducting (semi-) single-walled carbon nanotubes (SWNTs) must be purified of their metallic (met-) counterparts for most applications including nanoelectronics, solar cells, chemical sensors, and artificial skins. Previous bulk sorting techniques are based on subtle contrasts between properties of different nanotube/dispersing agent complexes. We report here a method which directly exploits the nanotube band structure differences. For the heterogeneous redox reaction of SWNTs with oxygen/water couple, the aqueous pH can be tuned so that the redox kinetics is determined by the availability of nanotube electrons only at/near the Fermi level, as predicted quantitatively by the Marcus-Gerischer (MG) theory. Consequently, met-SWNTs oxidize much faster than semi-SWNTs and only met-SWNTs selectively reverse the sign of their measured surface zeta potential from negative to positive at the optimized acidic pH when suspended with nonionic surfactants. By passing the redox-reacted nanotubes through anionic hydrogel beads, we isolate semi-SWNTs to record high electrically verified purity above 99.94% ± 0.04%. This facile charge sign reversal (CSR)-based sorting technique is robust and can sort SWNTs with a broad diameter range.

  18. Purity, Victimhood and Agency: Fifteen years of the UN Trafficking Protocol

    Directory of Open Access Journals (Sweden)

    Marjan Wijers

    2015-04-01

    Full Text Available When the women’s movement reverted back to the nineteenth-century Victorian concept of ‘trafficking in women’ to address abuses of migrant women in the sex industry, it unwittingly adopted not only a highly morally biased concept—dividing women into innocent victims in need of rescue and guilty ones who can be abused with impunity—but also one with racist and nationalistic overtones. Despite efforts to counter these flaws, this inheritance continues to define the debate on trafficking today, exemplified by the distinction made by the United Nations Trafficking Protocol between so-called ‘sexual exploitation’ and ‘labour exploitation’ and its focus on the aspects of recruitment and movement. As a result, its implementation in the last fifteen years has led to a range of oppressive measures against sex workers and migrants in the name of combating trafficking. The focus on the purity and victimhood of women, coupled with the protection of national borders, not only impedes any serious effort to address the exploitation of human beings under forced labour and slavery-like conditions, but actually causes harm. The call of the anti-trafficking movement for a human rights-based approach does not necessarily solve these fundamental problems, as it tends to restrict itself to protecting the rights of trafficked persons, while neglecting or even denying the human rights of sex workers and migrants.

  19. Purity and stability of online-prepared hemodiafiltration fluid after storage.

    Science.gov (United States)

    Corradi, V; Cruz, D; Vázquez-Rangel, A; Furlan, F; Grillone, R; Bonaccorsi, A; Cazzavillan, S; de Cal, M; Frisone, P; Morea, A; Brendolan, A; Rassu, M; Ronco, C

    2013-01-01

    Previous studies have suggested that online hemodiafiltration (OL-HDF) fluid can be used as dialysate for continuous renal replacement therapies, and thus HDF costs can be reduced. The aims of this study were to determine the purity of OL-HDF fluid and to verify the stability of the electrolyte composition and acid-base balance during its storage. OL-HDF fluid was collected in 70 individual bags and stored for up to 7 days. The following tests were performed daily in 10 bags: natural visible precipitation (macrocrystallization), sample collection for chemical analysis and fluid culture, limulus amebocyte lysate endotoxin test, standard culture of NALGENE® filters after passing of the fluid, and molecular analysis of bacterial DNA. The values of pH and pCO(2) showed a significant change starting at 24 h (p values were beyond the measurable range. Coefficient of variation for pCO(2) was as high as 25.7%. Electrolyte composition (Na(+), K(+), Cl(-), Ca(2+) and glucose) showed a statistically significant difference over time (p bags in future studies. Copyright © 2013 S. Karger AG, Basel.

  20. EAARL coastal topography-western Florida, post-Hurricane Charley, 2004: seamless (bare earth and submerged.

    Science.gov (United States)

    Nayegandhi, Amar; Bonisteel, Jamie M.; Wright, C. Wayne; Sallenger, A.H.; Brock, John C.; Yates, Xan

    2010-01-01

    Project Description These remotely sensed, geographically referenced elevation measurements of lidar-derived seamless (bare-earth and submerged) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Coastal and Marine Geology Program (CMGP), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the western Florida coastline beachface, acquired post-Hurricane Charley on August 17 and 18, 2004. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then