WorldWideScience

Sample records for metal analong systems

  1. Direct measurement of anisotropy of interfacial free energy from grain boundary groove morphology in transparent organic metal analong systems

    Energy Technology Data Exchange (ETDEWEB)

    Rustwick, Bryce A. [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    Both academia and industry alike have paid close attention to the mechanisms of microstructural selection during the solidification process. The forces that give rise to and the principles which rule the natural selection of particular morphologies are important to understanding and controlling new microstructures. Interfacial properties play a very crucial role to the selection of such microstructure formation. In the solidification of a metallic alloy, the solid-liquid interface is highly mobile and responds to very minute changes in the local conditions. At this interface, the driving force must be large enough to drive solute diffusion, maintain local curvature, and overcome the kinetic barrier to move the interface. Therefore, the anisotropy of interfacial free energy with respect to crystallographic orientation is has a significant influence on the solidification of metallic systems. Although it is generally accepted that the solid-liquid interfacial free energy and its associated anisotropy are highly important to the overall selection of morphology, the confident measurement of these particular quantities remains a challenge, and reported values are scarce. Methods for measurement of the interfacial free energy include nucleation experiments and grain boundary groove experiments. The predominant method used to determine anisotropy of interfacial energy has been equilibrium shape measurement. There have been numerous investigations involving grain boundaries at a solid-liquid interface. These studies indicated the GBG could be used to describe various interfacial energy values, which affect solidification. Early studies allowed for an estimate of interfacial energy with respect to the GBG energy, and finally absolute interfacial energy in a constant thermal gradient. These studies however, did not account for the anisotropic nature of the material at the GBG. Since interfacial energy is normally dependent on orientation of the crystallographic plane of the

  2. Hydrogen-metal systems

    International Nuclear Information System (INIS)

    Wenzl, H.; Springer, T.

    1976-01-01

    A survey is given on the alloys of metal crystals with hydrogen. The system niobium-hydrogen and its properties are especially dealt with: diffusion and heat of solution of hydrogen in the host crystal, phase diagram, coherent and incoherent phase separation, application of metal-hydrogen systems in technology. Furthermore, examples from research work in IFF (Institut fuer Festkoerperforschung) of the Nuclear Research Plant, Juelich, in the field of metal-H systems are given in summary form. (GSC) [de

  3. Improvement on control of waste disposal system at Genkai Nuclear Power Station No.1 and No.2 unit

    International Nuclear Information System (INIS)

    Morooka, Masatoshi; Tsutsumi, Akria

    1989-01-01

    At Genkai Nuclear Power Station, the operational and control systems of the boric acid evaporator, waste liquid evaporator and gaseous waste disposal system were converted from general purpose analong systems to computer instrumentation and control systems in order to improve their operability and controllability. The equipments were operated by batch processing system, so plant operators were required to operate them manually. By introducing the computer instrumentation and control systems, the automatic operation of the equipments has become possible. Furthermore, it has become possible to monitor the relevant parameters intensively with a CRT in the operating room, and it contributes to the improvement of reliability and labor saving. The operation of No.1 plant was begun in October, 1975, and No.2 plant in March, 1981. Both are the PWR plants of 625 MVA capacity. The outline of the power station facilities, the background of the reconstruction, the problems and the plan of reconstruction for the boric acid recovery facility, waste liquid evaporator and gas compressor, the peculiarity of the reconstruction works, and the effect of introducing the new systems are reported. (Kako, I.)

  4. Advances in metal forming expert system for metal forming

    CERN Document Server

    Hingole, Rahulkumar Shivajirao

    2015-01-01

    This comprehensive book offers a clear account of the theory and applications of advanced metal forming. It provides a detailed discussion of specific forming processes, such as deep drawing, rolling, bending extrusion and stamping. The author highlights recent developments of metal forming technologies and explains sound, new and powerful expert system techniques for solving advanced engineering problems in metal forming. In addition, the basics of expert systems, their importance and applications to metal forming processes, computer-aided analysis of metalworking processes, formability analysis, mathematical modeling and case studies of individual processes are presented.

  5. Ion-beam-mixing in metal-metal systems and metal-silicon systems

    International Nuclear Information System (INIS)

    Hung, L.

    1984-01-01

    The influence of energetic ion bombardment on the composition and structure of thin film materials and utilization of ion-beam-mixing techniques to modify interfacial reactions are reported in this thesis. The phase formation in metals by using ion mixing techniques has been studied. Upon ion irradiation of Al/Pt, Al/Pd and Al/Ni thin films, only the simplest intermetallic compounds of PdAl and NiAl were formed in crystalline structure, while the amorphous phase has been observed over a large range of composition. Ion mixing of Au/Cu bilayers resulted in the formation of substitutional solid solutions with no trace of ordered compounds. The formation of the ordered compound CuAu was achieved either by irradiation of bilayers with Ar ions at elevated substrate temperature or by irradiation of the mixed layers with He ions at relatively low temperature. In the Au/Al system several crystal compounds existed in the as-deposited samples. These phases remained crystalline or transformed into other equilibrium compounds upon ion irradiation. The results suggest that the phase formation by ion mixing is dependent on the high quench rate in the collision cascade region and the atomic mobility at the irradiation temperature. The argument can be applied to silicide forming systems. With near-noble metals, the mixed atoms are mobile and form metallurgically distinct phases. With refractory metals, amorphous phases are formed due to lack of atomic mobility

  6. 29 CFR 1926.758 - Systems-engineered metal buildings.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Systems-engineered metal buildings. 1926.758 Section 1926... Systems-engineered metal buildings. (a) All of the requirements of this subpart apply to the erection of systems-engineered metal buildings except §§ 1926.755 (column anchorage) and 1926.757 (open web steel...

  7. Charge transfer in gold--alkali-metal systems

    International Nuclear Information System (INIS)

    Watson, R.E.; Weinert, M.

    1994-01-01

    Based on conventional electronegativity arguments, gold--alkali-metal compounds are expected to be among the most ''ionic'' of metallic compounds. The concepts of ionicity and charge transfer are difficult to quantify. However, the changes in bonding in the 50/50 Au--alkali-metal systems between the elemental metals and the compounds are so severe that observations can readily be made concerning their character. The results, as obtained from self-consistent electronic-structure calculations, lead to the apparently odd observation that the electron density at the alkali-metal sites in the compound increases significantly and this involves high l componennts in the charge density. This increase, however, can be attributed to Au-like orbitals spatially overlapping the alkali-metal sites. In a chemical sense, it is reasonable to consider the alkali-metal transferring charge to these Au orbitals. While normally the difference in heats of formation between muffin-tin and full-potential calculations for transition-metal--transition-metal and transition-metal--main-group (e.g., Al) compounds having high site symmetry are small, for the gold--alkali-metal systems, the changes in bonding in the compounds cause differences of ∼0.5 eV/atom between the two classes of potential. Any serious estimate of the electronic structure in these systems must account for these aspherical bonding charges. The origin of the semiconducting behavior of the heavy-alkali-metal Au compounds is shown to arise from a combination of the Au-Au separations and the ionic character of the compounds; the light-alkali-metal Au compounds, with their smaller Au-Au separations, do not have a semiconducting gap. Core-level shifts and isomer shifts are also briefly discussed

  8. Low-Cost Metal Hydride Thermal Energy Storage System for Concentrating Solar Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Zidan, Ragaiy [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hardy, B. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Corgnale, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Teprovich, J. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Ward, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Motyka, Ted [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-01-31

    The objective of this research was to evaluate and demonstrate a metal hydride-based TES system for use with a CSP system. A unique approach has been applied to this project that combines our modeling experience with the extensive material knowledge and expertise at both SRNL and Curtin University (CU). Because of their high energy capacity and reasonable kinetics many metal hydride systems can be charged rapidly. Metal hydrides for vehicle applications have demonstrated charging rates in minutes and tens of minutes as opposed to hours. This coupled with high heat of reaction allows metal hydride TES systems to produce very high thermal power rates (approx. 1kW per 6-8 kg of material). A major objective of this work is to evaluate some of the new metal hydride materials that have recently become available. A problem with metal hydride TES systems in the past has been selecting a suitable high capacity low temperature metal hydride material to pair with the high temperature material. A unique aspect of metal hydride TES systems is that many of these systems can be located on or near dish/engine collectors due to their high thermal capacity and small size. The primary objective of this work is to develop a high enthalpy metal hydride that is capable of reversibly storing hydrogen at high temperatures (> 650 °C) and that can be paired with a suitable low enthalpy metal hydride with low cost materials. Furthermore, a demonstration of hydrogen cycling between the two hydride beds is desired.

  9. Environmental tests of metallization systems for terrestrial photovoltaic cells

    Science.gov (United States)

    Alexander, P., Jr.

    1985-01-01

    Seven different solar cell metallization systems were subjected to temperature cycling tests and humidity tests. Temperature cycling excursions were -50 deg C to 150 deg C per cycle. Humidity conditions were 70 deg C at 98% relative humidity. The seven metallization systems were: Ti/Ag, Ti/Pd/Ag, Ti/Pd/Cu, Ni/Cu, Pd/Ni/Solder, Cr/Pd/Ag, and thick film Ag. All metallization systems showed a slight to moderate decrease in cell efficiencies after subjection to 1000 temperature cycles. Six of the seven metallization systems also evidenced slight increases in cell efficiencies after moderate numbers of cycles, generally less than 100 cycles. The copper based systems showed the largest decrease in cell efficiencies after temperature cycling. All metallization systems showed moderate to large decreases in cell efficiencies after 123 days of humidity exposure. The copper based systems again showed the largest decrease in cell efficiencies after humidity exposure. Graphs of the environmental exposures versus cell efficiencies are presented for each metallization system, as well as environmental exposures versus fill factors or series resistance.

  10. Metal Allergy and Systemic Contact Dermatitis: An Overview

    Directory of Open Access Journals (Sweden)

    Yoko Yoshihisa

    2012-01-01

    Full Text Available Contact dermatitis is produced by external skin exposure to an allergen, but sometimes a systemically administered allergen may reach the skin and remain concentrated there with the aid of the circulatory system, leading to the production of systemic contact dermatitis (SCD. Metals such as nickel, cobalt, chromium, and zinc are ubiquitous in our environment. Metal allergy may result in allergic contact dermatitis and also SCD. Systemic reactions, such as hand dermatitis or generalized eczematous reactions, can occur due to dietary nickel or cobalt ingestion. Zinc-containing dental fillings can induce oral lichen planus, palmoplantar pustulosis, and maculopapular rash. A diagnosis of sensitivity to metal is established by epicutaneous patch testing and oral metal challenge with metals such as nickel, cobalt, chromium, and zinc. In vitro tests, such as the lymphocyte stimulating test (LST, have some advantages over patch testing to diagnose allergic contact dermatitis. Additionally, the determination of the production of several cytokines by primary peripheral blood mononuclear cell cultures is a potentially promising in vitro method for the discrimination of metal allergies, including SCD, as compared with the LST.

  11. Metal hydride-based thermal energy storage systems

    Science.gov (United States)

    Vajo, John J.; Fang, Zhigang

    2017-10-03

    The invention provides a thermal energy storage system comprising a metal-containing first material with a thermal energy storage density of about 1300 kJ/kg to about 2200 kJ/kg based on hydrogenation; a metal-containing second material with a thermal energy storage density of about 200 kJ/kg to about 1000 kJ/kg based on hydrogenation; and a hydrogen conduit for reversibly transporting hydrogen between the first material and the second material. At a temperature of 20.degree. C. and in 1 hour, at least 90% of the metal is converted to the hydride. At a temperature of 0.degree. C. and in 1 hour, at least 90% of the metal hydride is converted to the metal and hydrogen. The disclosed metal hydride materials have a combination of thermodynamic energy storage densities and kinetic power capabilities that previously have not been demonstrated. This performance enables practical use of thermal energy storage systems for electric vehicle heating and cooling.

  12. Recent materials compatibility studies in refractory metal-alkali metal systems for space power applications.

    Science.gov (United States)

    Harrison, R. W.; Hoffman, E. E.; Davies, R. L.

    1972-01-01

    Advanced Rankine and other proposed space power systems utilize refractory metals in contact with both single-phase and two-phase alkali metals at elevated temperatures. A number of recent compatibility experiments are described which emphasize the excellent compatibility of refractory metals with the alkali metals, lithium, sodium, and potassium, under a variety of environmental conditions. The alkali metal compatibilities of tantalum-, columbium-, molybdenum-, and tungsten-base alloys are discussed.

  13. Ultra-low magnetic damping in metallic and half-metallic systems

    Science.gov (United States)

    Shaw, Justin

    The phenomenology of magnetic damping is of critical importance to devices which seek to exploit the electronic spin degree of freedom since damping strongly affects the energy required and speed at which a device can operate. However, theory has struggled to quantitatively predict the damping, even in common ferromagnetic materials. This presents a challenge for a broad range of applications in magnonics, spintronics and spin-orbitronics that depend on the ability to precisely control the damping of a material. I will discuss our recent work to precisely measure the intrinsic damping in several metallic and half-metallic material systems and compare experiment with several theoretical models. This investigation uncovered a metallic material composed of Co and Fe that exhibit ultra-low values of damping that approach values found in thin film YIG. Such ultra-low damping is unexpected in a metal since magnon-electron scattering dominates the damping in conductors. However, this system possesses a distinctive feature in the bandstructure that minimizes the density of states at the Fermi energy n(EF). These findings provide the theoretical framework by which such ultra-low damping can be achieved in metallic ferromagnets and may enable a new class of experiments where ultra-low damping can be combined with a charge current. Half-metallic Heusler compounds by definition have a bandgap in one of the spin channels at the Fermi energy. This feature can also lead to exceptionally low values of the damping parameter. Our results show a strong correlation of the damping with the order parameter in Co2MnGe. Finally, I will provide an overview of the recent advances in achieving low damping in thin film Heusler compounds.

  14. Reaction phases and diffusion paths in SiC/metal systems

    Energy Technology Data Exchange (ETDEWEB)

    Naka, M.; Fukai, T. [Osaka Univ., Osaka (Japan); Schuster, J.C. [Vienna Univ., Vienna (Austria)

    2004-07-01

    The interface structures between SiC and metal are reviewed at SiC/metal systems. Metal groups are divided to carbide forming metals and non-carbide forming metals. Carbide forming metals form metal carbide granular or zone at metal side, and metal silicide zone at SiC side. The further diffusion of Si and C from SiC causes the formation of T ternary phase depending metal. Non-carbide forming metals form silicide zone containing graphite or the layered structure of metal silicide and metal silicide containing graphite. The diffusion path between SiC and metal are formed along tie-lines connecting SiC and metal on the corresponding ternary Si-C-M system. The reactivity of metals is dominated by the forming ability of carbide or silicide. Te reactivity tendency of elements are discussed on the periodical table of elements, and Ti among elements shows the highest reactivity among carbide forming metals. For non-carbide forming metals the reactivity sequence of metals is Fe>Ni>Co. (orig.)

  15. Quantum-size colloid metal systems

    International Nuclear Information System (INIS)

    Roldugin, V.I.

    2000-01-01

    In the review dealing with quantum-dimensional metallic colloid systems the methods of preparation, electronic, optical and thermodynamic properties of metal nanoparticles and thin films are considered, the effect of ionizing radiation on stability of silver colloid sols and existence of a threshold radiation dose affecting loss of stability being discussed. It is shown that sol stability loss stems from particles charge neutralization due to reduction of sorbed silver ions induced by radiation, which results in destruction of double electric layer on colloid particles boundary [ru

  16. Effect of metal shielding on a wireless power transfer system

    Science.gov (United States)

    Li, Jiacheng; Huang, Xueliang; Chen, Chen; Tan, Linlin; Wang, Wei; Guo, Jinpeng

    2017-05-01

    In this paper, the effect of non-ferromagnetic metal shielding (NFMS) material on the resonator of wireless power transfer (WPT) is studied by modeling, simulation and experimental analysis. And, the effect of NFMS material on the power transfer efficiency (PTE) of WPT systems is investigated by circuit model. Meanwhile, the effect of ferromagnetic metal shielding material on the PTE of WPT systems is analyzed through simulation. A double layer metal shield structure is designed. Experimental results demonstrate that by applying the novel double layer metal shielding method, the system PTE increases significantly while the electromagnetic field of WPT systems declines dramatically.

  17. Effect of metal shielding on a wireless power transfer system

    Directory of Open Access Journals (Sweden)

    Jiacheng Li

    2017-05-01

    Full Text Available In this paper, the effect of non-ferromagnetic metal shielding (NFMS material on the resonator of wireless power transfer (WPT is studied by modeling, simulation and experimental analysis. And, the effect of NFMS material on the power transfer efficiency (PTE of WPT systems is investigated by circuit model. Meanwhile, the effect of ferromagnetic metal shielding material on the PTE of WPT systems is analyzed through simulation. A double layer metal shield structure is designed. Experimental results demonstrate that by applying the novel double layer metal shielding method, the system PTE increases significantly while the electromagnetic field of WPT systems declines dramatically.

  18. Unified computational model of transport in metal-insulating oxide-metal systems

    Science.gov (United States)

    Tierney, B. D.; Hjalmarson, H. P.; Jacobs-Gedrim, R. B.; Agarwal, Sapan; James, C. D.; Marinella, M. J.

    2018-04-01

    A unified physics-based model of electron transport in metal-insulator-metal (MIM) systems is presented. In this model, transport through metal-oxide interfaces occurs by electron tunneling between the metal electrodes and oxide defect states. Transport in the oxide bulk is dominated by hopping, modeled as a series of tunneling events that alter the electron occupancy of defect states. Electron transport in the oxide conduction band is treated by the drift-diffusion formalism and defect chemistry reactions link all the various transport mechanisms. It is shown that the current-limiting effect of the interface band offsets is a function of the defect vacancy concentration. These results provide insight into the underlying physical mechanisms of leakage currents in oxide-based capacitors and steady-state electron transport in resistive random access memory (ReRAM) MIM devices. Finally, an explanation of ReRAM bipolar switching behavior based on these results is proposed.

  19. On the metallic-like behaviour in dilute two dimensional systems

    International Nuclear Information System (INIS)

    Hamilton, A.R.; Simmons, M.Y.; University of Cambridge, Cambridge,; Pepper, M.; Ritchie, D.A.

    2000-01-01

    Full text: In the past five years numerous experimental studies of a wide variety of low disorder two dimensional (2D) semiconductor systems have revealed an unexpectedly large decrease in the resistance as the temperature is lowered from T ∼ 1 K, suggesting the existence of a 2D metal. Although numerous theories have been put forward to explain this metallic-like behaviour (which contradicts the expectations of one parameter scaling theory), its origins, and the question of whether it persists to T 0, are still subjects of great debate. Recent experiments have shown that despite the strong interactions (r s = 10) these systems still exhibit Fermi liquid behaviour, and that the drop in resistance with decreasing T is not quantum in origin. These results therefore argue against the existence of a true 2D metallic phase, and we now address the final remaining question - what then is the origin of the widely observed metallic-like drop in resistance in 2D systems? We present a study of the metallic behaviour in low density GaAs hole systems, and Si electron systems, close to the apparent 2D 'metal' -insulator transition. The strength of the metallic behaviour is shown to be almost independent of the symmetry of the confining potential, and is predominantly determined by the low temperature resistivity (i.e. by k F l). Furthermore in both material systems the fractional change in the conductivity depends only on T/T F , independent of the carrier density. Although the origins of the metallic behaviour remain unexplained, our results rule out interactions, the shape of the potential well and spin-orbit effects as possible causes

  20. Buckminsterfullerenes: a non-metal system for nitrogen fixation.

    Science.gov (United States)

    Nishibayashi, Yoshiaki; Saito, Makoto; Uemura, Sakae; Takekuma, Shin-Ichi; Takekuma, Hideko; Yoshida, Zen-Ichi

    2004-03-18

    In all nitrogen-fixation processes known so far--including the industrial Haber-Bosch process, biological fixation by nitrogenase enzymes and previously described homogeneous synthetic systems--the direct transformation of the stable, inert dinitrogen molecule (N2) into ammonia (NH3) relies on the powerful redox properties of metals. Here we show that nitrogen fixation can also be achieved by using a non-metallic buckminsterfullerene (C60) molecule, in the form of a water-soluble C60:gamma-cyclodextrin (1:2) complex, and light under nitrogen at atmospheric pressure. This metal-free system efficiently fixes nitrogen under mild conditions by making use of the redox properties of the fullerene derivative.

  1. Cleanable sintered metal filters in hot off-gas systems

    International Nuclear Information System (INIS)

    Schurr, G.A.

    1981-01-01

    Filters with sintered metal elements, arranged as tube bundles with backflush air cleaning, are the equivalent of bag filters for high-temperature, harsh environments. They are virtually the only alternative for high-temperature off-gas systems where a renewable, highly efficient particle trap is required. Tests were conducted which show that the sintered metal elements installed in a filter system provide effective powder collection in high-temperature atmospheres over thousands of cleaning cycles. Such a sintered metal filter system is now installed on the experimental defense waste calciner at the Savannah River Laboratory. The experimental results included in this paper were used as the basis for its design

  2. System and process for aluminization of metal-containing substrates

    Science.gov (United States)

    Chou, Yeong-Shyung; Stevenson, Jeffry W

    2015-11-03

    A system and method are detailed for aluminizing surfaces of metallic substrates, parts, and components with a protective alumina layer in-situ. Aluminum (Al) foil sandwiched between the metallic components and a refractory material when heated in an oxidizing gas under a compression load at a selected temperature forms the protective alumina coating on the surface of the metallic components. The alumina coating minimizes evaporation of volatile metals from the metallic substrates, parts, and components in assembled devices during operation at high temperature that can degrade performance.

  3. System and process for aluminization of metal-containing substrates

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Yeong-Shyung; Stevenson, Jeffry W.

    2017-12-12

    A system and method are detailed for aluminizing surfaces of metallic substrates, parts, and components with a protective alumina layer in-situ. Aluminum (Al) foil sandwiched between the metallic components and a refractory material when heated in an oxidizing gas under a compression load at a selected temperature forms the protective alumina coating on the surface of the metallic components. The alumina coating minimizes evaporation of volatile metals from the metallic substrates, parts, and components in assembled devices that can degrade performance during operation at high temperature.

  4. Impact of heavy metals on the female reproductive system

    Directory of Open Access Journals (Sweden)

    Piotr Rzymski

    2015-05-01

    Full Text Available Introduction. It has been recognized that environmental pollution can affect the quality of health of the human population. Heavy metals are among the group of highly emitted contaminants and their adverse effect of living organisms has been widely studied in recent decades. Lifestyle and quality of the ambient environment are among these factors which can mainly contribute to the heavy metals exposure in humans. Objective. A review of literature linking heavy metals and the female reproductive system and description of the possible associations with emission and exposure of heavy metals and impairments of female reproductive system according to current knowledge. Results. The potential health disorders caused by chronic or acute heavy metals toxicity include immunodeficiency, osteoporosis, neurodegeneration and organ failures. Potential linkages of heavy metals concentration found in different human organs and blood with oestrogen-dependent diseases such as breast cancer, endometrial cancer, endometriosis and spontaneous abortions, as well as pre-term deliveries, stillbirths and hypotrophy, have also been reported. Conclusions. Environmental deterioration can lead to the elevated risk of human exposure to heavy metals, and consequently, health implications including disturbances in reproduction. It is therefore important to continue the investigations on metal-induced mechanisms of fertility impairment on the genetic, epigenetic and biochemical level.

  5. High temperature microcalorimetry. Study of metal-oxygen systems

    International Nuclear Information System (INIS)

    Tetot, R.; Picard, C.; Boureau, G.; Gerdanian, P.

    1981-01-01

    Determination of partial molar enthalpy in metal-oxygen systems at 1050 0 C. Three representative systems are studied: the solution of oxygen in titanium, the titanium-oxygen system and the uranium-oxygen system from UOsub(2.00) to UOsub(2.60) [fr

  6. Nuclear processes in deuterium/natural hydrogen-metal systems

    International Nuclear Information System (INIS)

    Zelensky, V.F.

    2013-01-01

    The survey presents the analysis of the phenomena taking place in deuterium - metal and natural hydrogen - metal systems under cold fusion experimental conditions. The cold fusion experiments have shown that the generation of heat and helium in the deuterium-metal system without emission of energetic gamma-quanta is the result of occurrence of a chain of chemical, physical and nuclear processes observed in the system, culminating in both the fusion of deuterium nuclei and the formation of a virtual, electron-modified excited 4He nucleus. The excitation energy of the helium nucleus is transferred to the matrix through emission of conversion electrons, and that, under appropriate conditions, provides a persistent synthesis of deuterium. The processes occurring in the deuterium/natural hydrogen - metal systems have come to be known as chemonuclear DD- and HD-fusion. The mechanism of stimulation of weak interaction reactions under chemonuclear deuterium fusion conditions by means of strong interaction reactions has been proposed. The results of numerous experiments discussed in the survey bear witness to the validity of chemonuclear fusion. From the facts discussed it is concluded that the chemonuclear deuterium fusion scenario as presented in this paper may serve as a basis for expansion of deeper research and development of this ecologically clean energy source. It is shown that the natural hydrogen-based system, containing 0.015% of deuterium, also has good prospects as an energy source. The chemonuclear fusion processes do not require going beyond the scope of traditional physics for their explanation

  7. Molybdenum-tin as a solar cell metallization system

    Science.gov (United States)

    Boyd, D. W.; Radics, C.

    1981-01-01

    The operations of solar cell manufacture are briefly examined. The formation of reliable, ohmic, low-loss, and low-cost metal contacts on solar cells is a critical process step in cell manufacturing. In a commonly used process, low-cost metallization is achieved by screen printing a metal powder-glass frit ink on the surface of the Si surface and the conductive metal powder. A technique utilizing a molybdenum-tin alloy for the metal contacts appears to lower the cost of materials and to reduce process complexity. The ink used in this system is formulated from MoO3 with Sn powder and a trace amount of titanium resonate. Resistive losses of the resulting contacts are low because the ink contains no frit. The MoO3 is finally melted and reduced in forming gas (N2+H2) to Mo metal. The resulting Mo is highly reactive which facilitates the Mo-Si bonding.

  8. Characterization of metal/humic acid systems by Capillary Electrophoresis

    NARCIS (Netherlands)

    Staden JJ van; Hoop MAGT van den; Cleven R; LAC

    2000-01-01

    Metal-humic acid systems have been characterised applying Capillary Electrophoresis (CE). Appropriate experimental conditions with respect to carrier electrolyte, pH range, salt concentration, humic acid concentration and the applied potential, have been optimised. The influence of multivalent metal

  9. Electrochemical metal speciation in natural and model polyelectrolyte systems

    OpenAIRE

    Hoop, van den, M.A.G.T.

    1994-01-01

    The purpose of the research described in this thesis was to examine the applicability of electro-analytical techniques in obtaining information on the speciation of metals, i.e. their distribution over different physico-chemical forms, in aquatic systems containing charged macromolecules. In chapter 1 a general introduction is given to (i) metal speciation in aquatic systems, (ii) (bio)polyelectrolytes and their counterion distributions and (iii) electrochemical ...

  10. Optical performance and metallic absorption in nanoplasmonic systems.

    Science.gov (United States)

    Arnold, Matthew D; Blaber, Martin G

    2009-03-02

    Optical metrics relating to metallic absorption in representative plasmonic systems are surveyed, with a view to developing heuristics for optimizing performance over a range of applications. We use the real part of the permittivity as the independent variable; consider strengths of particle resonances, resolving power of planar lenses, and guiding lengths of planar waveguides; and compare nearly-free-electron metals including Al, Cu, Ag, Au, Li, Na, and K. Whilst the imaginary part of metal permittivity has a strong damping effect, field distribution is equally important and thus factors including geometry, real permittivity and frequency must be considered when selecting a metal. Al performs well at low permittivities (e.g. sphere resonances, superlenses) whereas Au & Ag only perform well at very negative permittivities (shell and rod resonances, LRSPP). The alkali metals perform well overall but present engineering challenges.

  11. Molten metal feed system controlled with a traveling magnetic field

    International Nuclear Information System (INIS)

    Praeg, W.F.

    1991-01-01

    This patent describes a continuous metal casting system in which the feed of molten metal controlled by means of a linear induction motor capable of producing a magnetic traveling wave in a duct that connects a reservoir of molten metal to a caster. The linear induction motor produces a traveling magnetic wave in the duct in opposition to the pressure exerted by the head of molten metal in the reservoir

  12. Design and Development of a Portable Metal Chip Baler using A System Design Approach

    Directory of Open Access Journals (Sweden)

    Hassan Mohd Fahrul

    2017-01-01

    Full Text Available A large amount of metal chips at workplace will result in untidy and unsafe condition thus measurements of safety are needed in some industries, where the metal chips will be collected and put into a container until the volume is sufficient to be recycled. Due to that reason, the metal chips require a lot of spaces for storage before going to recycle. In this study, a portable metal chip baler as a device for compacting those metal chips is presented based on a system approach of engineering design. Basically, the system design evolves through four phases of development that are started from conceptual design, preliminary system design, detail design and development to system test and evaluation. The portable metal chip baler uses current technology such as pneumatic cylinder to compress the metal chips so that the system capable to operate efficiently. The output from this system is the metal chips are compacted into a block shape and a working prototype was developed to prove the concept of the system. As a summary, the conceptual design of portable metal chip baler was proven and was presented using the philosophy of the systems design approach. This tool may assists workers especially in the Small-Medium Enterprise (SME manufacturing industries, school or universities’ workshops for managing metal chips easily and systematically.

  13. The metallicity distribution of H I systems in the EAGLE cosmological simulations

    Science.gov (United States)

    Rahmati, Alireza; Oppenheimer, Benjamin D.

    2018-06-01

    The metallicity of strong H I systems, spanning from damped Lyman α absorbers (DLAs) to Lyman-limit systems (LLSs), is explored between z = 5 → 0 using the EAGLE high-resolution cosmological hydrodynamic simulation of galaxy formation. The metallicities of LLSs and DLAs steadily increase with time in agreement with observations. DLAs are more metal rich than LLSs, although the metallicities in the LLS column density range (N_{H I }≈ 10^{17}-10^{20} cm^{-2}) are relatively flat, evolving from a median H I-weighted metallicity of {Z}≲ 10^{-2} Z_{⊙} at z = 3 to ≈10-0.5 Z⊙ by z = 0. The metal content of H I systems tracks the increasing stellar content of the Universe, holding ≈ 5 {per cent} of the integrated total metals released from stars at z = 0. We also consider partial LLS (pLLS, N_{H I}≈ 10^{16}-10^{17} cm^{-2}) metallicities, and find good agreement with Wotta et al. for the fraction of systems above (37 per cent) and below (63 per cent) 0.1 Z⊙. We also find a large dispersion of pLLS metallicities, although we do not reproduce the observed metallicity bimodality and instead we make the prediction that a larger sample will yield more pLLSs around 0.1 Z⊙. We underpredict the median metallicity of strong LLSs, and predict a population of Z 3 that are not observed, which may indicate more widespread early enrichment in the real Universe compared to EAGLE.

  14. Proceedings of the Flat-Plate Solar Array Project Research Forum on Photovoltaic Metallization Systems

    Science.gov (United States)

    1983-01-01

    A photovoltaic Metallization Research forum, under the sponsorship of the Flat-Plate Solar Array Project consisted of five sessions, covering: (1) the current status of metallization systems, (2) system design, (3) thick-film metallization, (4) advanced techniques, and (5) future metallization challenges.

  15. Electronic specific heats in metal--hydrogen systems

    International Nuclear Information System (INIS)

    Flotow, H.E.

    1979-01-01

    The electronic specific heats of metals and metal--hydrogen systems can in many cases be evaluated from the measured specific heats at constant pressure, C/sub p/, in the temperature range 1 to 10 K. For the simplest case, C/sub p/ = γT + βT 3 , where γT represents the specific heat contribution associated with the conduction electrons, and βT 3 represents lattice specific heat contribution. The electronic specific heat coefficient, γ, is important because it is proportional to electron density of states at the Fermi surface. A short description of a low temperature calorimetric cryostat employing a 3 He/ 4 He dilution refrigeration is given. Various considerations and complications encountered in the evaluation of γ from specific heat data are discussed. Finally, the experimental values of γ for the V--Cr--H system and for the Lu--H system are summarized and the variations of γ as function of alloy composition are discussed

  16. Displacements of Metallic Thermal Protection System Panels During Reentry

    Science.gov (United States)

    Daryabeigi, Kamran; Blosser, Max L.; Wurster, Kathryn E.

    2006-01-01

    Bowing of metallic thermal protection systems for reentry of a previously proposed single-stage-to-orbit reusable launch vehicle was studied. The outer layer of current metallic thermal protection system concepts typically consists of a honeycomb panel made of a high temperature nickel alloy. During portions of reentry when the thermal protection system is exposed to rapidly varying heating rates, a significant temperature gradient develops across the honeycomb panel thickness, resulting in bowing of the honeycomb panel. The deformations of the honeycomb panel increase the roughness of the outer mold line of the vehicle, which could possibly result in premature boundary layer transition, resulting in significantly higher downstream heating rates. The aerothermal loads and parameters for three locations on the centerline of the windward side of this vehicle were calculated using an engineering code. The transient temperature distributions through a metallic thermal protection system were obtained using 1-D finite volume thermal analysis, and the resulting displacements of the thermal protection system were calculated. The maximum deflection of the thermal protection system throughout the reentry trajectory was 6.4 mm. The maximum ratio of deflection to boundary layer thickness was 0.032. Based on previously developed distributed roughness correlations, it was concluded that these defections will not result in tripping the hypersonic boundary layer.

  17. Atomistic modeling of an impurity element and a metal-impurity system: pure P and Fe-P system

    International Nuclear Information System (INIS)

    Ko, Won-Seok; Lee, Byeong-Joo; Kim, Nack J

    2012-01-01

    An interatomic potential for pure phosphorus, an element that has van der Waals, covalent and metallic bonding character, simultaneously, has been developed for the purpose of application to metal-phosphorus systems. As a simplification, the van der Waals interaction, which is less important in metal-phosphorus systems, was omitted in the parameterization process and potential formulation. On the basis of the second-nearest-neighbor modified embedded-atom method (2NN MEAM) interatomic potential formalism applicable to both covalent and metallic materials, a potential that can describe various fundamental physical properties of a wide range of allotropic or transformed crystalline structures of pure phosphorus could be developed. The potential was then extended to the Fe-P binary system describing various physical properties of intermetallic compounds, bcc and liquid alloys, and also the segregation tendency of phosphorus on grain boundaries of bcc iron, in good agreement with experimental information. The suitability of the present potential and the parameterization process for atomic scale investigations about the effects of various non-metallic impurity elements on metal properties is demonstrated. (paper)

  18. System for Prevention, Detection and Response to Radioactive Materials in Scrap Metal in Ukraine

    Energy Technology Data Exchange (ETDEWEB)

    Makarovska, O., E-mail: makarovska@hq.snrc.gov.ua [State Nuclear Regulatory Committee of Ukraine, Kiev (Ukraine)

    2011-07-15

    The State control system to prevent, detect and respond to cases of radioactive material in scrap metal is functioning in Ukraine. The system includes regulations for the safe and secure management of metal scrap and administrative and technical measures to prevent, detect and respond to cases of radioactive material in scrap metal. The key elements of prevention are the system of licensing and supervision in the sphere of radioactive material use and the State system for inventory, registration and control of radiation sources. Metal scrap management is licensed by the Ministry of Industrial Policy and one of the licence conditions is radiation control of the scrap metal. State supervision of the operations with metal scrap is provided by Ministry of Health and Ministry of Environmental Protection according to the regulation 'State sanitary-ecological standard for metal scrap management'. Specific standards exist for the export of metal scrap. Export consignments are followed by a certificate that proves the radiological safety of the metal. Ukrainian metallurgical plants provide an input radiation control of metal scrap and an output control of the produced metal. Thus, there exists a five barrier system of metal scrap control: border control; exclusion zone perimeter control; metal scrap dealers control; metallurgical plants (input control and output control of produced metal); and export consignments radiological certification. To regain control over orphan sources (including occasional radioactive material in the scrap metal) the 'procedure for interaction of executive authorities and involved legal entities in case of revealing of radiation sources in no legal use' was approved by a Resolution of the Cabinet of Ministers of Ukraine. The investigation of each case with feedback, information of involved bodies, safe and secure storage of restored radioactive material are provided according to this procedure. (author)

  19. Metallization systems for stable ohmic contacts to GaAs

    International Nuclear Information System (INIS)

    Tandon, J.L.; Douglas, K.D.; Vendura, G.; Kolawa, E.; So, F.C.T.; Nicolet, M.A.

    1986-01-01

    A metallization scheme to form reproducible and stable ohmic contacts to GaAs is described. The approach is based on the configuration: GaAs/X/Y/Z; where X is a thin metal film (e.g. Pt, Ti, Pd, Ru), Y is an electrically conducting diffusion barrier layer (TiN, W or W/sub 0.7/N/sub 0.3/), and Z is a thick metal layer (e.g. Ag) typically required for bonding or soldering purposes. The value and reproducibility of the contact resistance in these metallization systems results from the uniform steady-state solid-phase reaction of the metal X with GaAs. The stability of the contacts is achieved by the diffusion barrier layer Y, which not only confines the reaction of X with GaAs, but also prevents the top metal layer Z from interfering with this reaction. Applications of such contacts in fabricating stable solar cells are also discussed

  20. Fluorescence from a quantum dot and metallic nanosphere hybrid system

    Energy Technology Data Exchange (ETDEWEB)

    Schindel, Daniel G. [Department of Mathematics and Statistics, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB, R3B 2E9 (Canada); Singh, Mahi R. [Department of Physics and Astronomy, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 3K7 (Canada)

    2014-03-31

    We present energy absorption and interference in a quantum dot-metallic nanosphere system embedded on a dielectric substrate. A control field is applied to induce dipole moments in the nanosphere and the quantum dot, and a probe field is applied to monitor absorption. Dipole moments in the quantum dot or the metal nanosphere are induced, both by the external fields and by each other's dipole fields. Thus, in addition to direct polarization, the metal nanosphere and the quantum dot will sense one another via the dipole-dipole interaction. The density matrix method was used to show that the absorption spectrum can be split from one peak to two peaks by the control field, and this can also be done by placing the metal sphere close to the quantum dot. When the two are extremely close together, a self-interaction in the quantum dot produces an asymmetry in the absorption peaks. In addition, the fluorescence efficiency can be quenched by the addition of a metal nanosphere. This hybrid system could be used to create ultra-fast switching and sensing nanodevices.

  1. Operational management system for warehouse logistics of metal trading companies

    Directory of Open Access Journals (Sweden)

    Khayrullin Rustam Zinnatullovich

    2014-07-01

    Full Text Available Logistics is an effective tool in business management. Metal trading business is a part of metal promotion chain from producer to consumer. It's designed to serve as a link connecting the interests of steel producers and end users. We should account for the specifics warehousing trading. The specificity of warehouse metal trading consists primarily in the fact that the purchase is made in large lots, and the sale - in medium and small parties. Loading and unloading of cars and trucks is produced by overhead cranes. Some part of the purchased goods are shipped in relatively large lots without presales preparation. Another part of the goods undergoes presale preparation. Indoor and outdoor warehouses are used with the address storage system. In the process of prolonged storage the metal rusts. Some part of the goods is subjected to final completion (cutting, welding, coloration in service centers and small factories, usually located at the warehouse. The quantity of simultaneously shipped cars, and the quantity of the loader workers brigade can reach few dozens. So it is necessary to control the loading workers, to coordinate and monitor the performance of loading and unloading operations, to make the daily analysis of their work, to evaluate the warehouse operations as a whole. There is a need to manage and control movement of cars and trucks on the warehouse territory to reduce storage and transport costs and improve customer service. ERP-systems and WMS-systems, which are widely used, do not cover fully the functions and processes of the warehouse trading, and do not effectively manage all logistics processes. In this paper the specialized software is proposed. The software is intended for operational logistics management in warehouse metal products trading. The basic functions and processes of metal warehouse trading are described. The effectiveness indices for logistics processes and key effective indicators of warehouse trading are proposed

  2. The theory of dissipative structures of the kinetic system for defects of nonlinear physical system 'metal+loading+irradiation'. Part 3

    International Nuclear Information System (INIS)

    Tarasov, V.A.; Borikov, T.L.; Kryzhanovskaya, T.V.; Chernezhenko, S.A.; Rusov, V.D.

    2007-01-01

    The kinetic system for defects of physical nonlinear system 'metal + load + irradiation' is specified [1, 2, 3]. Developing the approaches offered in [4], where distinctions of mechanisms of radiating creep and areas of their applicability are formalized (depending on external parameters) for fuel and constructional metals, division of kinetic systems for defects of constructional and fuel metals is carrying out. Thus the accent on the autocatalytic features of kinetic system for defects of reactor fuel metals, resulting from the exoenergic autocatalytic character of nuclear fission reactions being the main point defect source is done. In this part of the article the basic attention is given to the kinetic of sink drains for point defects. For kinetic systems of sinks-sources new approaches for the task of boundary conditions are offered. The possible structure of the computer program modelling kinetic system for defects of nonlinear physical system 'metal + load + irradiation' is considered

  3. Design of Heavy Metals Monitoring System in Water Based on WSN and GPRS

    Directory of Open Access Journals (Sweden)

    Ke Lin

    2014-04-01

    Full Text Available In order to realize the real-time monitoring of heavy metals in water environment, a new type of heavy metal monitoring system was developed. The system was composed of monitoring terminal, gateway, GPRS network and upper computer monitoring center. The system detected the heavy metal ion concentrations by ion-selective electrode array and came into the system error automatic compensation method in the detection process. The collecting data was transported to the monitoring center through the cooperation between the wireless sensor network constituted by CC2530 and General Packet Radio Service network. The test result shows that the system can increased precision dramatically and strengthens the real-time transmission capacity effectively. The system is reliable in transmission, high real-time performance, flexible in networking and can be applied to continuous remote monitoring of heavy metals pollution.

  4. Environmentally Benign Tribo-systems for Metal Forming

    DEFF Research Database (Denmark)

    Bay, Niels; Azushima, A.; Groche, P.

    2010-01-01

    The growing awareness of environmental issues and the requirements to establish solutions diminishing the impact on working environment as well as external environment has initiated ever increasing efforts to develop new, environmentally benign tribological systems for metal forming. The present ...

  5. Investigation of Ternary Transition-Metal Nitride Systems by Reactive Cosputtering

    NARCIS (Netherlands)

    Dover, R.B. Van; Hessen, B.; Werder, D.; Chen, C.-H.; Felder, R.J.

    1993-01-01

    A reactive dc cosputtering technique has been used to evaluate compound formation in bimetallic transition-metal nitride systems. A wide range in M-M’ composition can be studied in a single deposition run, and the method is applicable to nonalloying metal combinations. Using this technique, it was

  6. Microscopic Electron Dynamics in Metal Nanoparticles for Photovoltaic Systems

    Directory of Open Access Journals (Sweden)

    Katarzyna Kluczyk

    2018-06-01

    Full Text Available Nanoparticles—regularly patterned or randomly dispersed—are a key ingredient for emerging technologies in photonics. Of particular interest are scattering and field enhancement effects of metal nanoparticles for energy harvesting and converting systems. An often neglected aspect in the modeling of nanoparticles are light interaction effects at the ultimate nanoscale beyond classical electrodynamics. Those arise from microscopic electron dynamics in confined systems, the accelerated motion in the plasmon oscillation and the quantum nature of the free electron gas in metals, such as Coulomb repulsion and electron diffusion. We give a detailed account on free electron phenomena in metal nanoparticles and discuss analytic expressions stemming from microscopic (Random Phase Approximation—RPA and semi-classical (hydrodynamic theories. These can be incorporated into standard computational schemes to produce more reliable results on the optical properties of metal nanoparticles. We combine these solutions into a single framework and study systematically their joint impact on isolated Au, Ag, and Al nanoparticles as well as dimer structures. The spectral position of the plasmon resonance and its broadening as well as local field enhancement show an intriguing dependence on the particle size due to the relevance of additional damping channels.

  7. Borides of the group 1 metals of the periodic system

    International Nuclear Information System (INIS)

    Samsonov, G.V.; Serebryakova, T.I.; Neronov, V.A.

    1975-01-01

    The borides of alkali metals (lithium, sodium, potassium) and the metals of a copper subgroup (copper, silver, gold) are described. Consideration is given to the crystalline structure and state diagrams of the metal systems within the first group of the Periodic Table with boron. Existence, formation conditions and physico-chemical properties of binary boride phases are characterized. Conclusion is made as to the absence of interaction between boron and silver. Information on the interaction between gold and boron is scanty and conflicting. Methods are described suitable for the production of the borides of the metals within the first group of the Periodic Table [ru

  8. Proceedings of the flat-plate solar array project research forum on photovoltaic metallization systems

    Energy Technology Data Exchange (ETDEWEB)

    None

    1983-11-15

    A Photovoltaic Metallization Research Forum, under the sponsorship of the Jet Propulsion Laboratory's Flat-Plate Solar Array Project and the US Department of Energy, was held March 16-18, 1983 at Pine Mountain, Georgia. The Forum consisted of five sessions, covering (1) the current status of metallization systems, (2) system design, (3) thick-film metallization, (4) advanced techniques and (5) future metallization challenges. Twenty-three papers were presented.

  9. Fiber optic/cone penetrometer system for subsurface heavy metals detection

    International Nuclear Information System (INIS)

    Saggese, S.; Greenwell, R.

    1995-01-01

    The objective of this project is to develop an integrated fiber optic sensor/cone penetrometer system to analyze the heavy metals content of the subsurface. This site characterization tool will use an optical fiber cable assembly which delivers high power laser energy to vaporize and excite a sample in-situ and return the emission spectrum from the plasma produced for chemical analysis. The chemical analysis technique, often referred to as laser induced breakdown spectroscopy (LIBS), has recently shown to be an effective method for the quantitative analysis of contaminants soils. By integrating the fiber optic sensor with the cone penetrometer, we anticipate that the resultant system will enable in-situ, low cost, high resolution, real-time subsurface characterization of numerous heavy metal soil contaminants simultaneously. There are several challenges associated with the integration of the LIBS sensor and cone penetrometer. One challenge is to design an effective means of optically accessing the soil via the fiber probe in the penetrometer. A second challenge is to develop the fiber probe system such that the resultant emission signal is adequate for quantitative analysis. Laboratory techniques typically use free space delivery of the laser to the sample. The high laser powers used in the laboratory cannot be used with optical fibers, therefore, the effectiveness of the LIBS system at the laser powers acceptable to fiber delivery must be evaluated. The primary objectives for this project are: (1) Establish that a fiber optic LIBS technique can be used to detect heavy metals to the required concentration levels; (2) Design and fabricate a fiber optic probe for integration with the penetrometer system for the analysis of heavy metals in soil samples; (3) Design, fabricate, and test an integrated fiber/penetrometer system; (4) Fabricate a rugged, field deployable laser source and detection hardware system; and (6) Demonstrate the prototype in field deployments

  10. Molten metal feed system controlled with a traveling magnetic field

    Science.gov (United States)

    Praeg, Walter F.

    1991-01-01

    A continuous metal casting system in which the feed of molten metal is controlled by means of a linear induction motor capable of producing a magnetic traveling wave in a duct that connects a reservoir of molten metal to a caster. The linear induction motor produces a traveling magnetic wave in the duct in opposition to the pressure exerted by the head of molten metal in the reservoir so that p.sub.c =p.sub.g -p.sub.m where p.sub.c is the desired pressure in the caster, p.sub.g is the gravitational pressure in the duct exerted by the force of the head of molten metal in the reservoir, and p.sub.m is the electromagnetic pressure exerted by the force of the magnetic field traveling wave produced by the linear induction motor. The invention also includes feedback loops to the linear induction motor to control the casting pressure in response to measured characteristics of the metal being cast.

  11. Liquid metal MHD generator systems

    International Nuclear Information System (INIS)

    Satyamurthy, P.; Dixit, N.S.; Venkataramani, N.; Rohatgi, V.K.

    1985-01-01

    Liquid Metal MHD (LMMHD) Generator Systems are becoming increasingly important in space and terrestrial applications due to their compactness and versatility. This report gives the current status and economic viability of LMMHD generators coupled to solar collectors, fast breeder reactors, low grade heat sources and conventional high grade heat sources. The various thermodynamic cycles in the temperatures range of 100degC-2000degC have been examined. The report also discusses the present understanding of various loss mechanisms inherent in LMMHD systems and the techniques for overcoming these losses. A small mercury-air LMMHD experimental facility being set up in Plasma Physics Division along with proposals for future development of this new technology is also presented in this report. (author)

  12. Screening of metal hydride pairs for closed thermal energy storage systems

    International Nuclear Information System (INIS)

    Aswin, N.; Dutta, Pradip; Murthy, S. Srinivasa

    2016-01-01

    Thermal energy storage systems based on metal/hydrides usually are closed systems composed of two beds of metal/alloy – one meant for energy storage and the other for hydrogen storage. It can be shown that a feasible operating cycle for such a system using a pair of metals/alloys operating between specified temperature values can be ensured if the equilibrium hydrogen intake characteristics satisfy certain criteria. In addition, application of first law of thermodynamics to an idealized operating cycle can provide the upper bounds of selected performance indices, namely volumetric energy storage density, energy storage efficiency and peak discharge temperature. This is demonstrated for a representative system composed of LaNi 4.7 Al 0.3 –LaNi 5 operating between 353 K and 303 K which gave values of about 56 kW h m −3 for volumetric storage density, about 85% for energy storage efficiency and 343 K for peak discharge temperature. A system level heat and mass transfer study considering the reaction kinetics, hydrogen flow between the beds and heat exchanger models is presented which gave second level estimates of about 40 kW h m −3 for volumetric energy storage density, 73% for energy storage efficiency and 334 K for peak temperature for the representative system. The results from such studies lead to identifying metal/alloy pairs which can be shortlisted for detailed studies.

  13. Alkali Metal Coolants. Proceedings of the Symposium on Alkali Metal Coolants - Corrosion Studies and System Operating Experience

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1967-06-15

    Proceedings of a Symposium organized by the IAEA and held in Vienna, 28 November - 2 December 1966. The meeting was attended by 107 participants from 16 countries and two international organizations. Contents: Review papers (2 papers); Corrosion of steels and metal alloys (6 papers); Mass transfer in alkali metal systems, behaviour of carbon (5 papers); Effects of sodium environment on mechanical properties of materials (3 papers); Effect of water leakage into sodium systems (2 papers); Design-and operation of testing apparatus (6 papers); Control, measurements and removal of impurities (13 papers); Corrosion by other alkali metals: NaK, K, Li, Cs (6 papers); Behaviour of fission products (3 papers). Each paper is in its original language (32 English, 6 French and 8 Russian) and is preceded by an abstract in English and one in the original language if this is not English. Discussions are in English. (author)

  14. Alkali Metal Coolants. Proceedings of the Symposium on Alkali Metal Coolants - Corrosion Studies and System Operating Experience

    International Nuclear Information System (INIS)

    1967-01-01

    Proceedings of a Symposium organized by the IAEA and held in Vienna, 28 November - 2 December 1966. The meeting was attended by 107 participants from 16 countries and two international organizations. Contents: Review papers (2 papers); Corrosion of steels and metal alloys (6 papers); Mass transfer in alkali metal systems, behaviour of carbon (5 papers); Effects of sodium environment on mechanical properties of materials (3 papers); Effect of water leakage into sodium systems (2 papers); Design-and operation of testing apparatus (6 papers); Control, measurements and removal of impurities (13 papers); Corrosion by other alkali metals: NaK, K, Li, Cs (6 papers); Behaviour of fission products (3 papers). Each paper is in its original language (32 English, 6 French and 8 Russian) and is preceded by an abstract in English and one in the original language if this is not English. Discussions are in English. (author)

  15. The development of PC-based real time ultrasonic metal thickness inspection system

    International Nuclear Information System (INIS)

    Suhairy Sani; Mohd Hanif Md Saad; Mohamad Pauzi Ismail; Ab Razak Hamzah; Abd Nassir Ibrahim; Amri Amin Abas

    2006-01-01

    This paper discusses the development of a PC-Based Real Time Ultrasonic Thickness Measurement system (UTMS) for metallic components such as pipes, pressure vessels and metal slabs. Metal thickness measurement for these components is crucial in industrial plants with dangerous environment, such as in oil and gas industry. From the measured metal thickness, a number of deductions could be made, for example the state and the rate of corrosion propagation inside a pipe or pressure vessel, etc. One of the most widely used methods in assessing metal thickness in industry is through the use of Ultrasonic technology. The benefits of using UTMS lies in the flexibility of data analysis, which includes signal processing, feature extraction, visualization capability and intelligent diagnosis. Data can be acquired in real-time and stored for future usage and application. The system was developed as a standalone computer software using Microsoft Visual-BASIC 6. (Author)

  16. Analysis of polariton dispersion in metal nanocomposite based novel superlattice system

    Science.gov (United States)

    DoniPon, V.; Joseph Wilson, K. S.; Malarkodi, A.

    2018-06-01

    The influence of metal nanoparticles in tuning the polaritonic gap in a novel piezoelectric superlattice is studied. Dielectric function of the metal nanoparticles is analyzed using Kawabata-Kubo effect and Drude's theory. The effective dielectric function of the nanocomposite system is studied using Maxwell Garnett approximation. Nanocomposite based LiTaO3 novel superlattice is formed by arranging the nanocomposite systems in such a way that their orientations are in the opposite direction. Hence there are two additional modes of propagation. The top most modes reflect the metal behavior of the nanoparticles. It is found that these modes of propagation vary with the filling factor. These additional modes of propagations can be exploited in the field of communication.

  17. Hybrid microcircuit metallization system for the SLL micro actuator

    International Nuclear Information System (INIS)

    Hampy, R.E.; Knauss, G.L.; Komarek, E.E.; Kramer, D.K.; Villaueva, J.

    1976-03-01

    A thin film technique developed for the SLL Micro Actuator in which both gold and aluminum can be incorporated on sapphire or fine grained alumina substrates in a two-level metallization system is described. Tungsten is used as a lateral transition metal permitting electrical contact between the gold and aluminum without the two metals coming in physical contact. Silicon dioxide serves as an insulator between the tungsten and aluminum for crossover purposes, and vias through the silicon dioxide permit interconnections where desired. Tungsten-gold is the first level conductor except at crossovers where tungsten only is used and aluminum is the second level conductor. Sheet resistances of the two levels can be as low as 0.01 ohm/square. Line widths and spaces as small as 0.025 mm can be attained. A second layer of silicon dioxide is deposited over the metallization and opened for all gold and aluminum bonding areas. The metallization system permits effective interconnection of a mixture of devices having both gold and aluminum terminations without creating undesirable gold-aluminum interfaces. Processing temperatures up to 400 0 C can be tolerated for short times without effect on bondability, conductor, and insulator characteristics, thus permitting silicon-gold eutectic die attachment, component soldering, and higher temperatures during gold lead bonding. Tests conducted on special test pattern circuits indicate good stability over the temperature range -55 to +150 0 C. Aging studies indicate no degradation in characteristics in tests of 500 h duration at 150 0 C

  18. Oxygen partial pressure: a key to alloying and discovery in metal oxide--metal eutectic systems

    International Nuclear Information System (INIS)

    Holder, J.D.; Clark, G.W.; Oliver, B.F.

    1978-01-01

    Control of oxygen partial pressure is essential in the directional solidification of oxide--metal eutectic composites by techniques involving gas-solid and gas-liquid interactions. The existence of end components in the eutectic composite is Po 2 sensitive as are melt stoichiometry, solid phase compositions, and vapor losses due to oxidation-volatilization. Simple criteria are postulated which can aid the experimentalist in selecting the proper gas mixture for oxide--metal eutectic composite growth. The Cr 2 O 3 --Mo--Cr systems was used to verify certain aspects of the proposed criteria

  19. Role of contact bonding on electronic transport in metal-carbon nanotube-metal systems

    International Nuclear Information System (INIS)

    Deretzis, I; La Magna, A

    2006-01-01

    We have investigated the effects of the interfacial bond arrangement on the electronic transport features of metal-nanotube-metal systems. The transport properties of finite, defect-free armchair and zigzag single-walled carbon nanotubes attached to Au(111) metallic contacts have been calculated by means of the non-equilibrium Green functional formalism with the tight-binding and the extended Hueckel Hamiltonians. Our calculations show that the electrode material is not the only factor which rules contact transparency. Indeed, for the same electrode, but changing nanotube helicities, we have observed an overall complex behaviour of the transmission spectra due to band mixing and interference. A comparison of the two models shows that the tight-binding approach fails to give a satisfactory representation of the transmission function when a more accurate description of the C-C and Au-C chemical bonds has to be considered. We have furthermore examined the effect of interface geometry variance on conduction and found that the contact-nanotube distance has a significant impact, while the contact-nanotube symmetry plays a marginal, yet evident role

  20. Interfacial transport phenomena and stability in liquid-metal/water systems: scaling considerations

    International Nuclear Information System (INIS)

    Abdulla, S.; Liu, X.; Anderson, M.; Bonazza, R.; Corradini, M.; Cho, D.

    2001-01-01

    One concept being considered for steam generation in innovative nuclear reactor applications, involves water coming into direct contact with a circulating molten metal. The vigorous agitation of the two fluids, the direct liquid-liquid contact and the consequent large interfacial area give rise to very high heat transfer coefficients and rapid steam generation. For an optimum design of such direct contact heat exchange and vaporization systems, detailed knowledge is necessary of the various flow regimes, interfacial transport phenomena, heat transfer and operational stability. In this paper we describe current results from the first year of this research that studies the transport phenomena involved with the injection of water into molten metals (e.g., lead alloys). In particular, this work discusses scaling considerations related to direct contact heat exchange, our experimental plans for investigation and a test plan for the important experimental parameters; i.e., the water and liquid metal mass flow rates, the liquid metal pool temperature and the ambient pressure of the direct contact heat exchanger. Past experimental work and initial scaling results suggest that our experiments can directly represent the proper liquid metal pool temperature and the water subcooling. The experimental variation in water and liquid metal flow rates and system pressure (1-10 bar), although smaller than the current conceptual system designs, is sufficient to verify the expected scale effects to demonstrate the phenomena. (authors)

  1. Critical and subcritical parameters of the system simulating plutonium metal dissolution

    International Nuclear Information System (INIS)

    Vasilev, Yury Yu.; Ryazanov, Boris G.; Sviridov, Victor I.; Mozhayeva, Lubov I.

    2003-01-01

    Dissolution of plutonium metal was simulated using the Monte Carlo computer code to calculate criticality safety limits for the process. Calculations were made for the constant masses of plutonium charged to the dissolving vessel considering distribution of plutonium in metal and solution phases. Critical parameters and limits were calculated as a function of dissolving vessel volume and plutonium metal mass. 240 Pu content was assumed to be from 0% to 10% (mass). Critical parameters were evaluated for the system with a water reflector. Results of this paper may be used in the designing process equipment for plutonium metal dissolution. (author)

  2. Advanced liquid metal reactor plant control system

    International Nuclear Information System (INIS)

    Dayal, Y.; Wagner, W.; Zizzo, D.; Carroll, D.

    1993-01-01

    The modular Advanced Liquid Metal Reactor (ALMR) power plant is controlled by an advanced state-of-the-art control system designed to facilitate plant operation, optimize availability, and protect plant investment. The control system features a high degree of automatic control and extensive amount of on-line diagnostics and operator aids. It can be built with today's control technology, and has the flexibility of adding new features that benefit plant operation and reduce O ampersand M costs as the technology matures

  3. Review of thermodinamic and mechanical properties of hydrogen-transition metal systems

    International Nuclear Information System (INIS)

    Mathias, H.; Katz, Y.

    1978-04-01

    A large body of fundamental and empirical knowledge has been acquired during many years of research concerning the interactions between hydrogen and metals, the location of hydrogen in metal structures, its mobility in metals and its influence on mechanical properties of metals. Much progress has been made in the understanding of related phenomena, and various theories have been proposed, but considerable disagreement still exist about basic mechanisms involved. The growing interest in these subjects and their important role in science and technology are well documented by many reviews and symposia. A general survey of these topics with reference to experimental results and theories related to thermodynamic and mechanical properties of hydrogen-transition metal systems, such as H-Pd, H-Ti, H-Fe etc. is given in the present review. Special emphasis is given to hydrogen embrittlement of metals

  4. Theory of quantum metal to superconductor transitions in highly conducting systems

    Energy Technology Data Exchange (ETDEWEB)

    Spivak, B.

    2010-04-06

    We derive the theory of the quantum (zero temperature) superconductor to metal transition in disordered materials when the resistance of the normal metal near criticality is small compared to the quantum of resistivity. This can occur most readily in situations in which 'Anderson's theorem' does not apply. We explicitly study the transition in superconductor-metal composites, in an swave superconducting film in the presence of a magnetic field, and in a low temperature disordered d-wave superconductor. Near the point of the transition, the distribution of the superconducting order parameter is highly inhomogeneous. To describe this situation we employ a procedure which is similar to that introduced by Mott for description of the temperature dependence of the variable range hopping conduction. As the system approaches the point of the transition from the metal to the superconductor, the conductivity of the system diverges, and the Wiedemann-Franz law is violated. In the case of d-wave (or other exotic) superconductors we predict the existence of (at least) two sequential transitions as a function of increasing disorder: a d-wave to s-wave, and then an s-wave to metal transition.

  5. High resolution Moessbauer spectroscopy with 67Zn in metallic systems

    International Nuclear Information System (INIS)

    Potzel, W.

    1985-01-01

    Moessbauer experiments on metallic systems are described where the high resolution 93.3 keV resonance in 67 Zn is used. In the first part, the Cu-Zn alloy system is investigated and the high energy resolution of this Moessbauer transition is employed to determine small changes of the s-electron density at the 67 Zn nucleus when the Zn concentration is changed. In the second part, Zn metal is taken as an example to demonstrate that the 93.3 keV transition is also extremely sensitive to small changes of lattice dynamical effects. 7 refs., 18 figs. (author)

  6. Zero-Valent Metallic Treatment System and Its Application for Removal and Remediation of Polychlorinated Biphenyls (Pcbs)

    Science.gov (United States)

    Quinn, Jacqueline W. (Inventor); Clausen, Christian A. (Inventor); Geiger, Cherie L. (Inventor); Brooks, Kathleen B. (Inventor)

    2012-01-01

    PCBs are removed from contaminated media using a treatment system including zero-valent metal particles and an organic hydrogen donating solvent. The treatment system may include a weak acid in order to eliminate the need for a coating of catalytic noble metal on the zero-valent metal particles. If catalyzed zero-valent metal particles are used, the treatment system may include an organic hydrogen donating solvent that is a non-water solvent. The treatment system may be provided as a "paste-like" system that is preferably applied to natural media and ex-situ structures to eliminate PCBs.

  7. Metallization of some simple systems

    International Nuclear Information System (INIS)

    Ross, M.; McMahan, A.K.

    1981-01-01

    We discuss the metallization of Xe, Ar, He, I 2 , H 2 , and N 2 in terms of some recent theoretical work and shock-wave experiments. New shock-wave data on liquid hydrogen and deuterium leads to a predicted pressure above 3 Mbar for the appearance of a monatomic metal phase. We expect CsI to become metallic near 0.8 Mbar

  8. Flow analysis of metals in a municipal solid waste management system

    International Nuclear Information System (INIS)

    Jung, C.H.; Matsuto, T.; Tanaka, N.

    2006-01-01

    This study aimed to identify the metal flow in a municipal solid waste (MSW) management system. Outputs of a resource recovery facility, refuse derived fuel (RDF) production facility, carbonization facility, plastics liquefaction facility, composting facility, and bio-gasification facility were analyzed for metal content and leaching concentration. In terms of metal content, bulky and incombustible waste had the highest values. Char from a carbonization facility, which treats household waste, had a higher metal content than MSW incinerator bottom ash. A leaching test revealed that Cd and Pb in char and Pb in RDF production residue exceeded the Japanese regulatory criteria for landfilling, so special attention should be paid to final disposal of these substances. By multiplying metal content and the generation rate of outputs, the metal content of input waste to each facility was estimated. For most metals except Cr, the total contribution ratio of paper/textile/plastics, bulky waste, and incombustible waste was over 80%. Approximately 30% of Cr originated from plastic packaging. Finally, several MSW management scenarios showed that most metals are transferred to landfills and the leaching potential of metals to the environment is quite small

  9. On the theory system of hydrothermal uranium metallization in China

    International Nuclear Information System (INIS)

    Du Letian

    2011-01-01

    Based on summarizing the mass of research outcome of the predecessors, the author attempts to make a brief generalization on the theory system of hydrothermal uranium mineralization in China. The system of uranium metallization is founded in the basic way of uranium source-migration-transportation-richment-reservation. The system mainly consists of the following frames: (1) mineralization type of silification zone; (2) age gap of mineralization to host rock; (3) alkli metasomatism; (4) metallogenic layer of crust; (5)integratation of 4 types mineralization (granite, volcanics, carbonaceous-siliceous-argilaceous rock and sandstone) in tectonic-hydrothermal process; (6) pre-enrichment process of metallization; (7) decouplement of granite magma evolution; (8) types of rich ore by high tempreture sericitization; (9)basalt event;(10) rock and ore formation by HARCON. (authors)

  10. Localized surface plasmon modes in a system of two interacting metallic cylinders

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Vergeles, Sergey S.; Vorobev, Petr E.

    2012-01-01

    We study an optical response of a system of two parallel close metallic cylinders having nanoscale dimensions. Surface plasmon excitation in the gap between the cylinders are specifically analyzed. In particular, resonance frequencies and field enhancement were investigated as functions of geomet......We study an optical response of a system of two parallel close metallic cylinders having nanoscale dimensions. Surface plasmon excitation in the gap between the cylinders are specifically analyzed. In particular, resonance frequencies and field enhancement were investigated as functions...... of geometrical characteristics of the system and Ohmic losses in the metal. The results of numerical simulations were systematically compared with the analytical theory, obtained in the quasi-static limit. The analytical method was generalized in order to take into account the retardation effects. We also...

  11. Electromagnetically induced transparency in a plasmonic system comprising of three metal-dielectric-metal parallel slabs: Plasmon- Plasmon interaction

    Directory of Open Access Journals (Sweden)

    M Moradbeigi

    2018-02-01

    Full Text Available In this paper, electromagnetically induced transparency (EIT in a system consisting of associated arrays of parallel slabs (metal-dielectric-metal is studied. The transmission coefficient, the reflection coefficient and the absorption coefficient as function of the incident light frequency by using the transfer matrix method is calculated and numerically discussed. Influence of the thickness of slab and the type of plasmonic metal on the induced transparency has been investigated. It is shown with decreasing the thickness of intermediate slab of length  (dielectric slab, the induced transparency increases due to the strong plasmon–plasmon couplings.

  12. Contributions regarding calculus and design of an ultrasonic system used in plasma metallization

    Science.gov (United States)

    Amza, G.

    2015-11-01

    Paper presents the calculus elements and construction for the ultrasonic system used in reconditioning process by metallization. A series of necessary elements used in ultrasonic system dimensioning are given and an ultrasonic system used in reconditioning process by plasma and grain metallization are presented. Also, a calculated ultrasonic system is modelled to work in resonance regime at the frequency f = 22Khz. Stress map inside material, internal energy variation, lost energy variation on length and volume unit are presented.

  13. Application of a modified electrochemical system for surface decontamination of radioactive metal waste

    International Nuclear Information System (INIS)

    Lee, J.H.; Lim, Y.K.; Yang, H.Y.; Shin, S.W.; Song, M.J.

    2003-01-01

    Conventional and modified electrolytic decontamination experiments were performed in a solution of sodium sulfate for the decontamination of carbon steel as the simulated metal wastes which are generated in large amounts from nuclear power plants. The effect of reaction time, current density and concentration of electrolytes in the modified electrolytic decontamination system were examined to remove the surface contamination of the simulated radioactive metal wastes. As for the results of this research, the modified electrochemical decontamination process can decontaminate more effectively than the conventional decontamination process by applying different anode material which causes higher induced electro-motive forces. When 0.5 M sodium sulfate, 0.4 A/cm 2 current density and 30 minutes reaction time were applied in the modified process, a 16 μm thickness change that is expected to remove most surface contamination in radioactive metal wastes was achieved on carbon steel which is the main material of radioactive metal waste in nuclear power plants. The decontamination efficiency of metal waste showed similar results with the small and large lab-scale modified electrochemical system. The application of this modified electrolytic decontamination system is expected to play a considerable role for decontamination of radioactive metal waste in nuclear power plants in the near future. (author)

  14. Dynamic screening and electron dynamics in low-dimensional metal systems

    International Nuclear Information System (INIS)

    Silkin, V.M.; Quijada, M.; Vergniory, M.G.; Alducin, M.; Borisov, A.G.; Diez Muino, R.; Juaristi, J.I.; Sanchez-Portal, D.; Chulkov, E.V.; Echenique, P.M.

    2007-01-01

    Recent advances in the theoretical description of dynamic screening and electron dynamics in metallic media are reviewed. The time-dependent building-up of screening in different situations is addressed. Perturbative and non-perturbative theories are used to study electron dynamics in low-dimensional systems, such as metal clusters, image states, surface states and quantum wells. Modification of the electronic lifetimes due to confinement effects is analyzed as well

  15. Removal of heavy-metal ions from dilute waste streams using membrane-based hybrid systems

    International Nuclear Information System (INIS)

    Friesen, D.T.; Edlund, D.J.

    1993-01-01

    At Bend research, the authors have developed hybrid systems that couple a process that removes solvent (water) and a process that removes solute (metal ions) such that toxic heavy-metal ions can be efficiently and selectively removed to very low levels while simultaneously concentrating the heavy-metal ions in relatively pure form. Although this technology is broadly applicable, the authors are focusing on the development of a system to treat groundwater that is contaminated with heavy-metal ions. The process utilizes coupled transport and reverse osmosis to reduce chromium and uranium concentration down to parts-per-billion levels

  16. ACCEPTABILITY ENVELOPE FOR METAL HYDRIDE-BASED HYDROGEN STORAGE SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, B.; Corgnale, C.; Tamburello, D.; Garrison, S.; Anton, D.

    2011-07-18

    The design and evaluation of media based hydrogen storage systems requires the use of detailed numerical models and experimental studies, with significant amount of time and monetary investment. Thus a scoping tool, referred to as the Acceptability Envelope, was developed to screen preliminary candidate media and storage vessel designs, identifying the range of chemical, physical and geometrical parameters for the coupled media and storage vessel system that allow it to meet performance targets. The model which underpins the analysis allows simplifying the storage system, thus resulting in one input-one output scheme, by grouping of selected quantities. Two cases have been analyzed and results are presented here. In the first application the DOE technical targets (Year 2010, Year 2015 and Ultimate) are used to determine the range of parameters required for the metal hydride media and storage vessel. In the second case the most promising metal hydrides available are compared, highlighting the potential of storage systems, utilizing them, to achieve 40% of the 2010 DOE technical target. Results show that systems based on Li-Mg media have the best potential to attain these performance targets.

  17. Tribo-systems for Sheet Metal Forming

    DEFF Research Database (Denmark)

    Bay, Niels

    2009-01-01

    The present paper gives an overview of more than 10 years work by the author’s research group through participation in national as well as international framework programmes on developing and testing environmentally friendly lubricants and tool materials and coatings inhibiting galling. Partners ......’s research group has especially been involved in the development of a system of tribo-tests for sheet metal forming and in testing and modelling of friction and limits of lubrication of new, environmentally friendly lubricants and tool materials....

  18. The most metal-poor damped Lyα systems: insights into chemical evolution in the very metal-poor regime

    DEFF Research Database (Denmark)

    Cooke, Ryan; Pettini, Max; Steidel, Charles C.

    2011-01-01

    We present a high spectral resolution survey of the most metal-poor damped Lyα absorption systems (DLAs) aimed at probing the nature and nucleosynthesis of the earliest generations of stars. Our survey comprises 22 systems with iron abundance less than 1/100 solar; observations of seven...... agreement with the values measured in Galactic halo stars when the oxygen abundance is measured from the [O i] λ6300 line. We speculate that such good agreement in the observed abundance trends points to a universal origin for these metals. In view of this agreement, we construct the abundance pattern...... the near-solar values of C/O in DLAs at the lowest metallicities probed, and find that their distribution is in agreement with that seen in Galactic halo stars. We find that the O/Fe ratio in VMP DLAs is essentially constant, and shows very little dispersion, with a mean [〈O/Fe〉]=+0.39 ± 0.12, in good...

  19. Heavy metal dynamics in the soil-leaf-fruit system under intensive apple cultivation

    Directory of Open Access Journals (Sweden)

    Murtić Senad

    2014-01-01

    Full Text Available One of the major problems confronting agricultural production is heavy metal contamination of agricultural soils, which imposes considerable limitations on productivity and leads to great consumer health and safety concerns about the products obtained on these soils. The objective of this study was to evaluate heavy metal dynamics in the soil-leaf-fruit system in an intensive apple cv. 'Idared' planting located in the Municipality of Goražde. Heavy metal contents in the soil samples and plant material were determined by atomic absorption spectrophotometry using a Shimadzu 7000 AA device, according to the instructions specified in the ISO 11047 method. The dynamics of the heavy metals analyzed, excepting zinc, in the soil-leaf-fruit system was characterized by relatively high total levels of heavy metals in the soil and a very low degree of their accumulation in the leaves and in particular the fruits. No fruit sample was found to have toxic levels of any of the heavy metals analyzed. In terms of soil contamination, this suggests the suitability of the study location for safe apple fruit production.

  20. Optimal Magnetic Field Shielding Method by Metallic Sheets in Wireless Power Transfer System

    Directory of Open Access Journals (Sweden)

    Feng Wen

    2016-09-01

    Full Text Available To meet the regulations established to limit human exposure to time-varying electromagnetic fields (EMFs such as the International Committee on Non-Ionizing Radiation Protection (ICNIRP guidelines, thin metallic sheets are often used to shield magnetic field leakage in high power applications of wireless power transfer (WPT systems based on magnetic field coupling. However, the metals in the vicinity of the WPT coils cause the decrease of self and mutual inductances and increase of effective series resistance; as such, the electric performance including transmission power and the efficiency of the system is affected. With the research objective of further investigating excellent shielding effectiveness associated with system performance, the utilization of the optimal magnetic field shielding method by metallic sheets in magnetic field coupling WPT is carried out in this paper. The circuit and 3D Finite Element Analysis (FEA models are combined to predict the magnetic field distribution and electrical performance. Simulation and experiment results show that the method is very effective by obtaining the largest possible coupling coefficient of the WPT coils within the allowable range and then reducing the value nearest to and no smaller than the critical coupling coefficient via geometric unbroken metallic sheets. The optimal magnetic field shielding method which considers the system efficiency, transmission power, transmission distance, and system size is also achieved using the analytic hierarchy process (AHP. The results can benefit WPT by helping to achieve efficient energy transfer and safe use in metal shielded equipment.

  1. Heavy Metal Exposure and Metabolic Syndrome: Evidence from Human and Model System Studies.

    Science.gov (United States)

    Planchart, Antonio; Green, Adrian; Hoyo, Cathrine; Mattingly, Carolyn J

    2018-03-01

    Metabolic syndrome (MS) describes the co-occurrence of conditions that increase one's risk for heart disease and other disorders such as diabetes and stroke. The worldwide increase in the prevalence of MS cannot be fully explained by lifestyle factors such as sedentary behavior and caloric intake alone. Environmental exposures, such as heavy metals, have been implicated, but results are conflicting and possible mechanisms remain unclear. To assess recent progress in determining a possible role between heavy metal exposure and MS, we reviewed epidemiological and model system data for cadmium (Cd), lead (Pb), and mercury (Hg) from the last decade. Data from 36 epidemiological studies involving 17 unique countries/regions and 13 studies leveraging model systems are included in this review. Epidemiological and model system studies support a possible association between heavy metal exposure and MS or comorbid conditions; however, results remain conflicting. Epidemiological studies were predominantly cross-sectional and collectively, they highlight a global interest in this question and reveal evidence of differential susceptibility by sex and age to heavy metal exposures. In vivo studies in rats and mice and in vitro cell-based assays provide insights into potential mechanisms of action relevant to MS including altered regulation of lipid and glucose homeostasis, adipogenesis, and oxidative stress. Heavy metal exposure may contribute to MS or comorbid conditions; however, available data are conflicting. Causal inference remains challenging as epidemiological data are largely cross-sectional; and variation in study design, including samples used for heavy metal measurements, age of subjects at which MS outcomes are measured; the scope and treatment of confounding factors; and the population demographics vary widely. Prospective studies, standardization or increased consistency across study designs and reporting, and consideration of molecular mechanisms informed by model

  2. Theoretical study of a novel solar trigeneration system based on metal hydrides

    International Nuclear Information System (INIS)

    Meng, Xiangyu; Yang, Fusheng; Bao, Zewei; Deng, Jianqiang; Serge, Nyallang N.; Zhang, Zaoxiao

    2010-01-01

    In order to utilize the low grade heat energy efficiently, the preliminary scheme of a metal hydride based Combined Cooling, Heating and Power (CCHP) system driven by solar energy and industrial waste heat was proposed, in which both refrigeration and power generation are achieved. Following a step-by-step procedure recently developed by the authors, two pairs of metal hydrides were selected for the CCHP system. The working principle of the system was discussed in detail and further design of the configuration for CCHP was conducted. Based on the cycle mentioned above, the models of energy conversion and exergy analysis were set up. The multi-element valued method was used to assess the performance of the CCHP system in a whole sense, thus the analysis of influence factors on the system performance can be carried out. The typical climate conditions of Xi'an in 2005 were taken for discussion, and the results showed that the system performance is mainly affected by the quantity of solar radiation energy. The objective of the system's optimization is to increase the exergy efficiency of the metal hydride heat pump, based on the quantity of solar radiation energy. The comparison with two different traditional types of CCHP systems proved that the novel CCHP system is superior to the traditional CCHP systems concerning the integrated performance.

  3. Experimental study of liquid-metal target designs of accelerating-controlled systems

    International Nuclear Information System (INIS)

    Iarmonov, Mikhail; Makhov, Kirill; Novozhilova, Olga; Meluzov, A.G.; Beznosov, A.V.

    2011-01-01

    Models of a liquid-metal target of an accelerator-controlled system have been experimentally studied at the Nizhny Novgorod State Technical University to develop an optimal design of the flow part of the target. The main explored variants of liquid-metal targets are: Design with a diaphragm (firm-and-impervious plug) mounted on the pipe tap of particle transport from the accelerator cavity to the working cavity of the liquid-metal target. Design without a diaphragm on the pipe tab of particle transport from the accelerator. The study was carried out in a high-temperature liquid-metal test bench under the conditions close to full-scale ones: the temperature of the eutectic lead-bismuth alloy was 260degC - 400degC, the coolant mass flow was 5-80 t/h, and the rarefaction in the gas cavity was 10 5 Pa, the coefficient of geometric similarity equal to 1. The experimental studies of hydrodynamic characteristics of flow parts in the designs of targets under full-scale conditions indicated high efficiency of a target in triggering, operating, and deactivating modes. Research and technology instructions for designs of the flow part of the liquid-metal target, the target design as a whole, and the target circuit of accelerator-controlled systems were formulated as a result of the studies. (author)

  4. Metal-metal-hofteproteser

    DEFF Research Database (Denmark)

    Ulrich, Michael; Overgaard, Søren; Penny, Jeannette

    2014-01-01

    In Denmark 4,456 metal-on-metal (MoM) hip prostheses have been implanted. Evidence demonstrates that some patients develope adverse biological reactions causing failures of MoM hip arthroplasty. Some reactions might be systemic. Failure rates are associated with the type and the design of the Mo...

  5. Texture-geometric deformational effects in some metal-hydrogen systems

    International Nuclear Information System (INIS)

    Spivak, L.V.; Kats, M.Ya.

    1992-01-01

    Possible deformation effects were studied in vanadium, tantalum, niobium, palladium and iron which occurred during electrolytic hydrogenation of specimens preliminarily deformed by torsion and then annealed. Noticeable texture-geometric effects were observed and related to the system tendency to enhance the degree of specimen form symmetry during hydrogenation. The latter was an off-beat realization of Le-Chatelier principle. It was assumed that the nature of deformation effects was connected with one of minimization channels for overall elastic stress fields in metals being hydrogenated. Some distinction was revealed in behaviour of 5a group metal, palladium and iron

  6. Development of Hydrogen Storage Tank Systems Based on Complex Metal Hydrides

    Directory of Open Access Journals (Sweden)

    Morten B. Ley

    2015-09-01

    Full Text Available This review describes recent research in the development of tank systems based on complex metal hydrides for thermolysis and hydrolysis. Commercial applications using complex metal hydrides are limited, especially for thermolysis-based systems where so far only demonstration projects have been performed. Hydrolysis-based systems find their way in space, naval, military and defense applications due to their compatibility with proton exchange membrane (PEM fuel cells. Tank design, modeling, and development for thermolysis and hydrolysis systems as well as commercial applications of hydrolysis systems are described in more detail in this review. For thermolysis, mostly sodium aluminum hydride containing tanks were developed, and only a few examples with nitrides, ammonia borane and alane. For hydrolysis, sodium borohydride was the preferred material whereas ammonia borane found less popularity. Recycling of the sodium borohydride spent fuel remains an important part for their commercial viability.

  7. Development of Hydrogen Storage Tank Systems Based on Complex Metal Hydrides

    Science.gov (United States)

    Ley, Morten B.; Meggouh, Mariem; Moury, Romain; Peinecke, Kateryna; Felderhoff, Michael

    2015-01-01

    This review describes recent research in the development of tank systems based on complex metal hydrides for thermolysis and hydrolysis. Commercial applications using complex metal hydrides are limited, especially for thermolysis-based systems where so far only demonstration projects have been performed. Hydrolysis-based systems find their way in space, naval, military and defense applications due to their compatibility with proton exchange membrane (PEM) fuel cells. Tank design, modeling, and development for thermolysis and hydrolysis systems as well as commercial applications of hydrolysis systems are described in more detail in this review. For thermolysis, mostly sodium aluminum hydride containing tanks were developed, and only a few examples with nitrides, ammonia borane and alane. For hydrolysis, sodium borohydride was the preferred material whereas ammonia borane found less popularity. Recycling of the sodium borohydride spent fuel remains an important part for their commercial viability. PMID:28793541

  8. Electrochemical metal speciation in natural and model polyelectrolyte systems

    NARCIS (Netherlands)

    Hoop, van den M.A.G.T.

    1994-01-01

    The purpose of the research described in this thesis was to examine the applicability of electro-analytical techniques in obtaining information on the speciation of metals, i.e. their distribution over different physico-chemical forms, in aquatic systems containing charged macromolecules.

  9. Transport properties of metal-metal and metal-insulator heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Fadlallah Elabd, Mohamed Mostafa

    2010-06-09

    In this study we present results of electronic structure and transport calculations for metallic and metal-insulator interfaces, based on density functional theory and the non-equilibrium Green's function method. Starting from the electronic structure of bulk Al, Cu, Ag, and Au interfaces, we study the effects of different kinds of interface roughness on the transmission coefficient (T(E)) and the I-V characteristic. In particular, we compare prototypical interface distortions, including vacancies, metallic impurities, non-metallic impurities, interlayer, and interface alloy. We find that vacancy sites have a huge effect on transmission coefficient. The transmission coefficient of non-metallic impurity systems has the same behaviour as the transmission coefficient of vacancy system, since these systems do not contribute to the electronic states at the Fermi energy. We have also studied the transport properties of Au-MgO-Au tunnel junctions. In particular, we have investigated the influence of the thickness of the MgO interlayer, the interface termination, the interface spacing, and O vacancies. Additional interface states appear in the O-terminated configuration due to the formation of Au-O bonds. An increasing interface spacing suppresses the Au-O bonding. Enhancement of T(E) depends on the position and density of the vacancies (the number of vacancies per unit cell). (orig.)

  10. THE SLUGGS SURVEY: NGC 3115, A CRITICAL TEST CASE FOR METALLICITY BIMODALITY IN GLOBULAR CLUSTER SYSTEMS

    International Nuclear Information System (INIS)

    Brodie, Jean P.; Conroy, Charlie; Arnold, Jacob A.; Romanowsky, Aaron J.; Usher, Christopher; Forbes, Duncan A.; Strader, Jay

    2012-01-01

    Due to its proximity (9 Mpc) and the strongly bimodal color distribution of its spectroscopically well-sampled globular cluster (GC) system, the early-type galaxy NGC 3115 provides one of the best available tests of whether the color bimodality widely observed in GC systems generally reflects a true metallicity bimodality. Color bimodality has alternatively been attributed to a strongly nonlinear color-metallicity relation reflecting the influence of hot horizontal-branch stars. Here, we couple Subaru Suprime-Cam gi photometry with Keck/DEIMOS spectroscopy to accurately measure GC colors and a CaT index that measures the Ca II triplet. We find the NGC 3115 GC system to be unambiguously bimodal in both color and the CaT index. Using simple stellar population models, we show that the CaT index is essentially unaffected by variations in horizontal-branch morphology over the range of metallicities relevant to GC systems (and is thus a robust indicator of metallicity) and confirm bimodality in the metallicity distribution. We assess the existing evidence for and against multiple metallicity subpopulations in early- and late-type galaxies and conclude that metallicity bi/multimodality is common. We briefly discuss how this fundamental characteristic links directly to the star formation and assembly histories of galaxies.

  11. THE SLUGGS SURVEY: NGC 3115, A CRITICAL TEST CASE FOR METALLICITY BIMODALITY IN GLOBULAR CLUSTER SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Brodie, Jean P.; Conroy, Charlie; Arnold, Jacob A.; Romanowsky, Aaron J. [University of California Observatories and Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Usher, Christopher; Forbes, Duncan A. [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia); Strader, Jay, E-mail: brodie@ucolick.org [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2012-11-10

    Due to its proximity (9 Mpc) and the strongly bimodal color distribution of its spectroscopically well-sampled globular cluster (GC) system, the early-type galaxy NGC 3115 provides one of the best available tests of whether the color bimodality widely observed in GC systems generally reflects a true metallicity bimodality. Color bimodality has alternatively been attributed to a strongly nonlinear color-metallicity relation reflecting the influence of hot horizontal-branch stars. Here, we couple Subaru Suprime-Cam gi photometry with Keck/DEIMOS spectroscopy to accurately measure GC colors and a CaT index that measures the Ca II triplet. We find the NGC 3115 GC system to be unambiguously bimodal in both color and the CaT index. Using simple stellar population models, we show that the CaT index is essentially unaffected by variations in horizontal-branch morphology over the range of metallicities relevant to GC systems (and is thus a robust indicator of metallicity) and confirm bimodality in the metallicity distribution. We assess the existing evidence for and against multiple metallicity subpopulations in early- and late-type galaxies and conclude that metallicity bi/multimodality is common. We briefly discuss how this fundamental characteristic links directly to the star formation and assembly histories of galaxies.

  12. Slip systems, dislocation boundaries and lattice rotations in deformed metals

    DEFF Research Database (Denmark)

    Winther, Grethe

    2009-01-01

    Metals are polycrystals and consist of grains, which are subdivided on a finer scale upon plastic deformation due to formation of dislocation boundaries. The crystallographic alignment of planar dislocation boundaries in face centred cubic metals, like aluminium and copper, deformed to moderate...... of the mechanical anisotropy of rolled sheets. The rotation of the crystallographic lattice in each grain during deformation also exhibits grain orientation dependence, originating from the slip systems. A combined analysis of dislocation boundaries and lattice rotations concludes that the two phenomena are coupled...

  13. Separation of rare earth metal using micro solvent extraction system

    International Nuclear Information System (INIS)

    Nishihama, S.; Tajiri, Y.; Yoshizuka, K.

    2005-01-01

    A micro solvent extraction system for the separation of rare earth metals has been investigated. The micro flow channel was fabricated on a PMMA plate. Extraction equilibrium was quickly achieved, without any mechanical mixing. The solvent extraction results obtained for the Pr/Sm binary solutions revealed that both rare earth metals are firstly extracted together. Following, the Pr is extracted in the organic solution and Sm remains in the aqueous phase. The phase separation can be successively achieved by contriving the cross section of the flow channel

  14. Decontamination of U-metal surface by an oxidation etching system

    Energy Technology Data Exchange (ETDEWEB)

    Stout, R.B.; Kansa, E.J.; Shaffer, R.J.; Weed, H.C. [California Univ., Livermore, CA (United States). Lawrence Livermore National Lab

    2001-07-01

    A surface treatment to remove surface contamination from uranium (U) metal and/or hydrides of uranium and heavy metals (HM) from U-metal parts is described. In the case of heavy metal atomic contamination on a surface, and potentially several atomic layers beneath, the surface oxidation treatment combines both chemical and chemically driven mechanical processes. The chemical process is a controlled temperature-time oxidation process to create a thin film of uranium oxide (UO{sub 2} and higher oxides) on the U-metal surface. The chemically driven mechanical process is strain induced by the volume increase as the U-metal surface transforms to a UO{sub 2} surface film. These volume strains are significantly large to cause surface failure spalling/scale formation and thus, removal of a U-oxide film that contains the HM-contaminated surface. The case of a HM-hydride surface contamination layer can be treated similarly by using inert hot gas to decompose the U-hydrides and/or HM-hydrides that are contiguous with the surface. A preliminary analysis to design and to plan for a sequence of tests is developed. The tests will provide necessary and sufficient data to evaluate the effective implementation and operational characteristics of a safe and reliable system. The following description is limited to only a surface oxidation process for HM-decontamination. (authors)

  15. Conceptual assessment and thermal hydraulic analysis of MVDS system for the dry storage of reduced metal fuel

    International Nuclear Information System (INIS)

    Lee, J. C.; Bang, K. S.; Shin, H. S.; Joo, J. S.; Su, K. S.; Kim, H. D.

    2003-01-01

    Conceptual assessment and thermal hydraulic analysis of MVDS storage system have been carried out for application of reduced metal fuel. The storage concept was established considering the optimum weight, storage volume and thermal efficiency. The capacity of MVDS system for loading the reduced metal fuel has four times as compared with existing PWR fuel storage system. In the results of thermal analysis, the maximum temperature of metal fuel was estimated to be 110 .deg. C which is lower than the allowable value under normal operation condition. Therefore, it is shown that the MVDS system can feasibly accomodate the reduced metal fuel in aspect of thermal safety

  16. Study of the Fracture Mechanisms of Electroplated Metallization Systems Using In Situ Microtension Test

    Science.gov (United States)

    Msolli, Sabeur; Kim, Heung Soo

    2018-03-01

    This framework assesses the mechanical behavior of some potential thin/thick metallization systems in use as either ohmic contacts for diamond semi-conductors or for metallization on copper double bounded ceramic substrates present in the next-generation power electronics packaging. The interesting and unique characteristic of this packaging is the use of diamond as a semi-conductor material instead of silicon to increase the lifetime of embedded power converters for use in aeronautical applications. Theoretically, such packaging is able to withstand temperatures of up to 300 °C without breaking the semi-conductor, provided that the constitutive materials of the packaging are compatible. Metallization is very important to protect the chips and substrates. Therefore, we address this issue in the present work. The tested metallization systems are Ni/Au, Ni/Cr/Au and Ni/Cr. These specific systems were studied since they can be used in conjunction with existing bonding technologies, including AuGe soldering, Ag-In Transient liquid Phase Bonding and silver nanoparticle sintering. The metallization is achieved via electrodeposition, and a mechanical test, consisting of a microtension technique, is carried out at room temperature inside a scanning electron microscopy chamber. The technique permits observations the cracks initiation and growth in the metallization to locate the deformation zones and identify the fracture mechanisms. Different failure mechanisms were shown to occur depending on the metallic layers deposited on top of the copper substrate. The density of these cracks depends on the imposed load and the involved metallization. These observations will help choose the metallization that is compatible with the particular bonding material, and manage mechanical stress due to thermal cycling so that they can be used as a constitutive component for high-temperature power electronics packaging.

  17. Identification of passive shutdown system parameters in a metal fueled LMR

    International Nuclear Information System (INIS)

    Vilim, R.B.

    1992-01-01

    This document discusses periodic testing of the passive shutdown system in a metal fueled liquid metal reactor which has been proposed as a Technical Specification requirement. In the approach to testing considered in this paper, perturbation experiments performed at normal operation are used to predict an envelope that bounds reactor response to flowrate, inlet temperature and external reactivity forcing functions. When the envelope for specific upsets lies within safety limits, one concludes that the passive shutdown system is operation properly for those upsets. Simulation results for the EBR-II reactor show that the response envelope for loss of flow and rod reactivity insertion events does indeed bound these events

  18. Metallic particles into mechanical and hydraulic systems in agricultural and construction machines

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jair Rosas da; Silva, Deise Paula da [Instituto Agronomico de Campinas (IAC), Campinas, SP (Brazil). Centro de Engenharia Agricola; Bormio, Marcos Roberto [Universidade Estadual Paulista (UNESP), Bauru, SP (Brazil). Fac. de Engenharia

    2008-07-01

    The lubricant oil analysis are an indicator of the conditions how the lubricant is, may to allow the prevision of damages that occurred into machine due to the internal abrasion of hydraulic and mechanical components of the machines. The present study had the objective to determine the kind and quantity of the metallic particles that occurred into the lubricant oil of the mechanical and hydraulic compartments of the energy transmission systems of three kinds of machines: a tracked-tractor, a sugarcane harvester and a group of power-shovels. The metallic particles presents into these compartments were determined under laboratory tests and concerning to the following elements: iron, copper, chromium, lead, nickel, aluminum, silex, tin and molybdenum. About to the tracked-tractor, the metallic contaminators into to the oil charges surpasses the tolerate levels, considering the technical standards adopted in this evaluation. In the sugarcane harvester only a metallic element in excess was identified and, in a power-shovel group it was showed the need to correct air false entrances in the hydraulic or mechanical systems due the high presence of silex element. (author)

  19. A new non-metallic anchorage system for post-tensioning applications using CFRP tendons

    Science.gov (United States)

    Taha, Mahmoud Reda

    The objective of the work described in this thesis is to design, develop and test a new non-metallic anchorage system for post-tensioning applications using CFRP tendons. The use of a non-metallic anchorage system should eliminate corrosion and deterioration concerns in the anchorage zone. The development of a reliable non-metallic anchorage would provide an important contribution to this field of knowledge. The idea of the new anchorage is to hold the tendon through mechanical gripping. The anchorage consists of a barrel with a conical housing and four wedges. The anchorage components are made of ultra high performance concrete (UHPC) specially developed for the anchorage. Sixteen concrete mixtures with different casting and curing regimes were examined to develop four UHPC mixtures with compressive strengths in excess of 200 MPa. The UHPC mixtures showed very dense microstructures with some unique characteristics. To enhance the fracture toughness of the newly developed UHPC, analytical and experimental analyses were performed. Using 3 mm chopped carbon fibres, a significant increase in the fracture toughness of UHPC was achieved. The non-metallic anchorage was developed with the UHPC with enhanced fracture toughness. The barrel required careful wrapping with CFRP sheets to provide the confinement required to utilize the strength and toughness of the UHPC. Thirty-three anchorages were tested under both static and dynamic loading conditions. The non-metallic anchorage showed excellent mechanical performance and fulfilled the different requirements of a post-tensioning anchorage system. The development of the new non-metallic anchorage will widen the inclusion of CFRP tendons in post-tensioned concrete/masonry structures. The new system will offer the opportunity to exploit CFRP tendons effectively creating an innovative generation of corrosion-free, smart structures.

  20. Inorganic concepts relevant to metal binding, activity, and toxicity in a biological system

    Energy Technology Data Exchange (ETDEWEB)

    Hoeschele, J.D. (Warner-Lambert Co., Ann Arbor, MI (USA). Parke-Davis Pharmaceutical Research Div.); Turner, J.E.; England, M.W. (Oak Ridge National Lab., TN (USA))

    1990-01-01

    The purpose of this paper is to review selected physical and inorganic concepts and factors which might be important in assessing and/or understanding the fact and disposition of a metal system in a biological environment. Hopefully, such inquiries will ultimately permit us to understand, rationalize, and predict differences and trends in biological effects as a function of the basic nature of a metal system and, in optimal cases, serve as input to a system of guidelines for the notion of Chemical Dosimetry.'' The plan of this paper is to first review, in general terms, the basic principles of the Crystal Field Theory (CFT), a unifying theory of bonding in metal complexes. This will provide the necessary theoretical background for the subsequent discussion of selected concepts and factors. 21 refs., 7 figs., 6 tabs.

  1. Heavy metal anomalies in the Tinto and Odiel River and estuary system, Spain

    Science.gov (United States)

    Nelson, C.H.; Lamothe, P.J.

    1993-01-01

    The Tinto and Odiel rivers drain 100 km from the Rio Tinto sulphide mining district, and join at a 20-km long estuary entering the Atlantic Ocean. A reconnaissance study of heavy metal anomalies in channel sand and overbank mud of the river and estuary by semi-quantitative emission dc-arc spectrographic analysis shows the following upstream to downstream ranges in ppm (??g g-1): As 3,000 to TOC), sandysilty overbank clay has been analyzed to represent suspended load materials. The high content of heavy metals in the overbank clay throughout the river and estuary systems indicates the importance of suspended sediment transport for dispersing heavy metals from natural erosion and anthropogenic mining activities of the sulfide deposit. The organic-poor (0.21-0.37% TOC) river bed sand has been analyzed to represent bedload transport of naturally-occurring sulfide minerals. The sand has high concentrations of metals upstream but these decrease an order of magnitude in the lower estuary. Although heavy metal contamination of estuary mouth beach sand has been diluted to background levels estuary mud exhibits increased contamination apparently related to finer grain size, higher organic carbon content, precipitation of river-borne dissolved solids, and input of anthropogenic heavy metals from industrial sources. The contaminated estuary mud disperses to the inner shelf mud belt and offshore suspended sediment, which exhibit metal anomalies from natural erosion and mining of upstream Rio Tinto sulphide lode sources (Pb, Cu, Zn) and industrial activities within the estuary (Fe, Cr, Ti). Because heavy metal contamination of Tinto-Odiel river sediment reaches or exceeds the highest levels encountered in other river sediments of Spain and Europe, a detailed analysis of metals in water and suspended sediment throughout the system, and epidemiological analysis of heavy metal effects in humans is appropriate. ?? 1993 Estuarine Research Federation.

  2. Principles and practices of lean production applied in a metal structures production system

    OpenAIRE

    Carvalho, Rogério; Alves, Anabela Carvalho; Lopes, Isabel da Silva

    2011-01-01

    This paper presents a work undertaken in a metal structures production system in a company producing several assorted products for the civil construction. The work aim was to improve the production process, solving several productive problems encountered in the production system, such as: deliveries delays, long lead times, too many material handling, high stocks, errors and defects in metal structures assembly and production, and unnecessary motions. The identified problems were analyzed and...

  3. Silicone metalization

    Energy Technology Data Exchange (ETDEWEB)

    Maghribi, Mariam N. (Livermore, CA); Krulevitch, Peter (Pleasanton, CA); Hamilton, Julie (Tracy, CA)

    2008-12-09

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  4. Highly reproducible alkali metal doping system for organic crystals through enhanced diffusion of alkali metal by secondary thermal activation.

    Science.gov (United States)

    Lee, Jinho; Park, Chibeom; Song, Intek; Koo, Jin Young; Yoon, Taekyung; Kim, Jun Sung; Choi, Hee Cheul

    2018-05-16

    In this paper, we report an efficient alkali metal doping system for organic single crystals. Our system employs an enhanced diffusion method for the introduction of alkali metal into organic single crystals by controlling the sample temperature to induce secondary thermal activation. Using this system, we achieved intercalation of potassium into picene single crystals with closed packed crystal structures. Using optical microscopy and Raman spectroscopy, we confirmed that the resulting samples were uniformly doped and became K 2 picene single crystal, while only parts of the crystal are doped and transformed into K 2 picene without secondary thermal activation. Moreover, using a customized electrical measurement system, the insulator-to-semiconductor transition of picene single crystals upon doping was confirmed by in situ electrical conductivity and ex situ temperature-dependent resistivity measurements. X-ray diffraction studies showed that potassium atoms were intercalated between molecular layers of picene, and doped samples did not show any KH- nor KOH-related peaks, indicating that picene molecules are retained without structural decomposition. During recent decades, tremendous efforts have been exerted to develop high-performance organic semiconductors and superconductors, whereas as little attention has been devoted to doped organic crystals. Our method will enable efficient alkali metal doping of organic crystals and will be a resource for future systematic studies on the electrical property changes of these organic crystals upon doping.

  5. Nuclear alkali metal Rankine power systems for space applications

    International Nuclear Information System (INIS)

    Moyers, J.C.; Holcomb, R.S.

    1986-08-01

    Nucler power systems utilizing alkali metal Rankine power conversion cycles offer the potential for high efficiency, lightweight space power plants. Conceptual design studies are being carried out for both direct and indirect cycle systems for steady state space power applications. A computational model has been developed for calculating the performance, size, and weight of these systems over a wide range of design parameters. The model is described briefly and results from parametric design studies, with descriptions of typical point designs, are presented in this paper

  6. Nuclear alkali metal Rankine power systems for space applications

    International Nuclear Information System (INIS)

    Moyers, J.C.; Holcomb, R.S.

    1986-01-01

    Nuclear power systems utilizing alkali metal Rankine power conversion cycles offer the potential for high efficiency, lightweight space power plants. Conceptual design studies are being carried out for both direct and indirect cycle systems for steady state space power applications. A computational model has been developed for calculating the performance, size, and weight of these systems over a wide range of design parameters. The model is described briefly and results from parametric design studies, with descriptions of typical point designs, are presented in this paper

  7. New solution of driving systems with the torsionally flexible metal coupling

    Directory of Open Access Journals (Sweden)

    Krzysztof FILIPOWICZ

    2008-01-01

    Full Text Available At work a conception was presented of structure of the new type of driving systems with the metal flexible torsional coupling. Depending on needs, from the type it coupled machines, applied in driving arrangements, it can have a different structural form. the advantages of the new coupling among others is the great permanence of a lack of non-metallic susceptible elements, possibility of moving great torques and considerable relieving momentary overload.

  8. Regularities in electroconductivity and thermo-emf in systems of binary continuous solid solutions of metals

    International Nuclear Information System (INIS)

    Vedernikov, M.V.; Dvunitkin, V.G.; Zhumagulov, A.

    1978-01-01

    Given are new experimental data about specific electric resistance of 10 systems of binary continuous solid metal solutions at the temperatures of 293 and 4.2 K: Cr-V, Mo-Nb, Mo-V, Cr-Mo, Nb-V, Ti-Zr, Hf-Zr, Hf-Ti, Sc-Zr, Sc-Hf. For the first time a comparative analysis of all available data on the resistance dependence on the composition of systems of continuous solid solutions, which covers 21 systems, is carried out. The ''resistance-composition'' dependence for such alloy systems is found to be of two types. The dependence of the first type is characteristic of the systems, formed by two isoelectronic metals, the dependence of the second type - for the systems, formed by non-isoelectronic metals. Thermo-emf of each type of solid solutions differently depends on their compositions

  9. Insulator–metal transition in a conservative system: An evidence for ...

    Indian Academy of Sciences (India)

    substrate, suggest that the mobility coalescence is responsible for the aging in island metal films. ... esting transition observed in a conservative system – after the stoppage of ... Oxidation of islands model and mobility coalescence model.

  10. Effects of metals on Legionella pneumophila growth in drinking water plumbing systems.

    Science.gov (United States)

    States, S J; Conley, L F; Ceraso, M; Stephenson, T E; Wolford, R S; Wadowsky, R M; McNamara, A M; Yee, R B

    1985-11-01

    An investigation of the chemical environment and growth of Legionella pneumophila in plumbing systems was conducted to gain a better understanding of its ecology in this habitat. Water samples were collected from hospital and institutional hot-water tanks known to have supported L. pneumophila and were analyzed for 23 chemical parameters. The chemical environment of these tanks was found to vary extensively, with the concentrations of certain metals reaching relatively high levels due to corrosion. The effect of various chemical conditions on L. pneumophila growth was then examined by observing its multiplication in the chemically analyzed hot-water tank samples after sterilization and reinoculation with L. pneumophila. L. pneumophila and associated microbiota used in these experiments were obtained from a hot-water tank. These stains were maintained in tap water and had never been passaged on agar. The results of the growth studies indicate that although elevated concentrations of a number of metals are toxic, lower levels of certain metals such as iron, zinc, and potassium enhance growth of naturally occurring L. pneumophila. Parallel observations on accompanying non-Legionellaceae bacteria failed to show the same relationship. These findings suggest that metal plumbing components and associated corrosion products are important factors in the survival and growth of L. pneumophila in plumbing systems and may also be important in related habitats such as cooling towers and air-conditioning systems.

  11. Development of an expert system for the simulation model for casting metal substructure of a metal-ceramic crown design.

    Science.gov (United States)

    Matin, Ivan; Hadzistevic, Miodrag; Vukelic, Djordje; Potran, Michal; Brajlih, Tomaz

    2017-07-01

    Nowadays, the integrated CAD/CAE systems are favored solutions for the design of simulation models for casting metal substructures of metal-ceramic crowns. The worldwide authors have used different approaches to solve the problems using an expert system. Despite substantial research progress in the design of experts systems for the simulation model design and manufacturing have insufficiently considered the specifics of casting in dentistry, especially the need for further CAD, RE, CAE for the estimation of casting parameters and the control of the casting machine. The novel expert system performs the following: CAD modeling of the simulation model for casting, fast modeling of gate design, CAD eligibility and cast ability check of the model, estimation and running of the program code for the casting machine, as well as manufacturing time reduction of the metal substructure. The authors propose an integration method using common data model approach, blackboard architecture, rule-based reasoning and iterative redesign method. Arithmetic mean roughness values was determinated with constant Gauss low-pass filter (cut-off length of 2.5mm) according to ISO 4287 using Mahr MARSURF PS1. Dimensional deviation between the designed model and manufactured cast was determined using the coordinate measuring machine Zeiss Contura G2 and GOM Inspect software. The ES allows for obtaining the castings derived roughness grade number N7. The dimensional deviation between the simulation model of the metal substructure and the manufactured cast is 0.018mm. The arithmetic mean roughness values measured on the casting substructure are from 1.935µm to 2.778µm. The realized developed expert system with the integrated database is fully applicable for the observed hardware and software. Values of the arithmetic mean roughness and dimensional deviation indicate that casting substructures are surface quality, which is more than enough and useful for direct porcelain veneering. The

  12. Mathematical modeling of the nickel/metal hydride battery system

    Energy Technology Data Exchange (ETDEWEB)

    Paxton, Blaine Kermit [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering

    1995-09-01

    A group of compounds referred to as metal hydrides, when used as electrode materials, is a less toxic alternative to the cadmium hydroxide electrode found in nickel/cadmium secondary battery systems. For this and other reasons, the nickel/metal hydride battery system is becoming a popular rechargeable battery for electric vehicle and consumer electronics applications. A model of this battery system is presented. Specifically the metal hydride material, LaNi{sub 5}H{sub 6}, is chosen for investigation due to the wealth of information available in the literature on this compound. The model results are compared to experiments found in the literature. Fundamental analyses as well as engineering optimizations are performed from the results of the battery model. In order to examine diffusion limitations in the nickel oxide electrode, a ``pseudo 2-D model`` is developed. This model allows for the theoretical examination of the effects of a diffusion coefficient that is a function of the state of charge of the active material. It is found using present data from the literature that diffusion in the solid phase is usually not an important limitation in the nickel oxide electrode. This finding is contrary to the conclusions reached by other authors. Although diffusion in the nickel oxide active material is treated rigorously with the pseudo 2-D model, a general methodology is presented for determining the best constant diffusion coefficient to use in a standard one-dimensional battery model. The diffusion coefficients determined by this method are shown to be able to partially capture the behavior that results from a diffusion coefficient that varies with the state of charge of the active material.

  13. An alternative approach to the management of reactive metals: tolerant cementitious systems

    International Nuclear Information System (INIS)

    Swift, P.; Cox, J.; Wise, M.; McKinney, J.; Rhodes, C.

    2015-01-01

    In recent years research has focused on preventing or minimising corrosion of reactive metals to ensure long-term waste package integrity. An alternative approach to the encapsulation of reactive metals is being explored. The approach will identify a cementitious-based encapsulating material that will allow corrosion of reactive metals to occur in a controlled and predictable manner, rather than seeking to limit or prevent the corrosion, whilst retaining waste package integrity. A low strength grout will be developed that will be 'tolerant' to the expansive forces generated by the corrosion products of reactive metals. Novel cementitious systems (e.g. foamed cements, rubber composite cements, cenosphere composite cements, lime mortars, bentonite cements etc.) that may be tolerant to potentially expansive waste products, such as reactive metals will be considered and assessed in a series of small-scale preliminary trials (compressive strength, porosity, permeability, pore solution pH, etc.)

  14. The behavior and effects of the noble metals in the DWPF melter system

    International Nuclear Information System (INIS)

    Hutson, N.D.; Smith, M.E.

    1992-01-01

    Fission-product noble metals have caused severe operating problems in numerous worldwide waste vitrification facilities. These dense, highly conductive noble metals have tended to accumulate on the floor of joule-heated glass melters causing electrical distortions which have, in some occurrences, rendered the melter inoperable. A pilot scale vitrification research facility at the U.S. Department of Energy's Savannah River Laboratory has been operated for more than a year with simulated feed streams containing noble metals. In this paper the behavior of these noble metals in the melter system and final glass product and their effects on the scaled DWPF-type melter are discussed

  15. Applications of some microscopic, diffraction and absorption techniques to the study of metal--hydrogen systems

    International Nuclear Information System (INIS)

    Pick, M.A.

    1979-01-01

    Several experimental techniques were reviewed which are used to investigate metal hydrogen systems. The first technique is metallography and optical microscopy. This is a very old technique which was found to be very powerful in the case of metal hydrogen systems. A few examples of such work are shown and the results are discussed

  16. Integrated DWPF Melter System (IDMS) campaign report: The first two noble metals operations

    International Nuclear Information System (INIS)

    Hutson, N.D.; Zamecnik, J.R.; Smith, M.E.; Miller, D.H.; Ritter, J.A.

    1991-01-01

    The Integrated DWPF Melter System (IDMS) is designed and constructed to provide an engineering-scale representation of the DWPF melter and its associated feed preparation and off-gas systems. The facility is the first pilot-scale melter system capable of processing mercury, and flowsheet levels of halides and noble metals. In order to characterize the processing of noble metals (Pd, Rh, Ru, and Ag) on a large scale, the IDMS will be operated batchstyle for at least nine feed preparation cycles. The first two of these operations are complete. The major observation to date occurred during the second run when significant amounts of hydrogen were evolved during the feed preparation cycle. The runs were conducted between June 7, 1990 and March 8, 1991. This time period included nearly six months of ''fix-up'' time when forced air purges were installed on the SRAT MFT and other feed preparation vessels to allow continued noble metals experimentation

  17. STM and synchrotron radiation studies of prototypical metal/semiconductor systems

    DEFF Research Database (Denmark)

    Lay, G. le; Aristov, V.Y.; Seehofer, L.

    1994-01-01

    Since the origin of surface science noble metal/elemental semiconductor couples have been considered as ''prototypical'' systems. After three decades of research their structural and electronic properties remain an intriguing maze despite recent advances made, especially thanks to the development...

  18. Thermodynamic properties of some metal oxide-zirconia systems

    Science.gov (United States)

    Jacobson, Nathan S.

    1989-01-01

    Metal oxide-zirconia systems are a potential class of materials for use as structural materials at temperatures above 1900 K. These materials must have no destructive phase changes and low vapor pressures. Both alkaline earth oxide (MgO, CaO, SrO, and BaO)-zirconia and some rare earth oxide (Y2O3, Sc2O3, La2O3, CeO2, Sm2O3, Gd2O3, Yb2O3, Dy2O3, Ho2O3, and Er2O3)-zirconia system are examined. For each system, the phase diagram is discussed and the vapor pressure for each vapor species is calculated via a free energy minimization procedure. The available thermodynamic literature on each system is also surveyed. Some of the systems look promising for high temperature structural materials.

  19. Application of a mixed metal oxide catalyst to a metallic substrate

    Science.gov (United States)

    Sevener, Kathleen M. (Inventor); Lohner, Kevin A. (Inventor); Mays, Jeffrey A. (Inventor); Wisner, Daniel L. (Inventor)

    2009-01-01

    A method for applying a mixed metal oxide catalyst to a metallic substrate for the creation of a robust, high temperature catalyst system for use in decomposing propellants, particularly hydrogen peroxide propellants, for use in propulsion systems. The method begins by forming a prepared substrate material consisting of a metallic inner substrate and a bound layer of a noble metal intermediate. Alternatively, a bound ceramic coating, or frit, may be introduced between the metallic inner substrate and noble metal intermediate when the metallic substrate is oxidation resistant. A high-activity catalyst slurry is applied to the surface of the prepared substrate and dried to remove the organic solvent. The catalyst layer is then heat treated to bind the catalyst layer to the surface. The bound catalyst layer is then activated using an activation treatment and calcinations to form the high-activity catalyst system.

  20. Recyclable hydrogen storage system composed of ammonia and alkali metal hydride

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Hikaru [Department of Quantum Matter, AdSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530 (Japan); Miyaoka, Hiroki; Hino, Satoshi [Institute for Advanced Materials Research, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530 (Japan); Nakanishi, Haruyuki [Higashi-Fuji Technical Center, Toyota Motor Corporation, 1200 Misyuku, Susono, Shizuoka 410-1193 (Japan); Ichikawa, Takayuki; Kojima, Yoshitsugu [Department of Quantum Matter, AdSM, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530 (Japan); Institute for Advanced Materials Research, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530 (Japan)

    2009-12-15

    Ammonia (NH{sub 3}) reacts with alkali metal hydrides MH (M = Li, Na, and K) in an exothermic reaction to release hydrogen (H{sub 2}) at room temperature, resulting that alkali metal amides (MNH{sub 2}) which are formed as by-products. In this work, hydrogen desorption properties of these systems and the condition for the recycle from MNH{sub 2} back to MH were investigated systematically. For the hydrogen desorption reaction, the reactivities of MH with NH{sub 3} were better following the atomic number of M on the periodic table, Li < Na < K. It was confirmed that the hydrogen absorption reaction of all the systems proceeded under 0.5 MPa of H{sub 2} flow condition below 300 C. (author)

  1. Grading the severity of soft tissue changes associated with metal-on-metal hip replacements: reliability of an MR grading system

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Helen; Cahir, John G.; Goodwin, Richard W. [Norfolk and Norwich University Hospital, Department of Radiology, Norwich, Norfolk (United Kingdom); Toms, Andoni Paul [Norfolk and Norwich University Hospital, Department of Radiology, Norwich, Norfolk (United Kingdom); Norwich Radiology Academy, Norwich (United Kingdom); Wimhurst, James; Nolan, John F. [Norfolk and Norwich University Hospital, Department of Orthopaedics, Norwich, Norfolk (United Kingdom)

    2011-03-15

    Metal-on-metal (MoM) soft tissue reactions or aseptic lymphocytic vasculitis-associated lesions (ALVAL) are being recognised using metal artefact reduction (MAR) MR with increasing frequency following the advent of second generation metal-on-metal bearings, but there is no standardised technique for reporting of MR appearances in this disease. The aim of this study was to measure the reliability of a grading system designed for scoring the severity of MoM disease on MRI. MRI examinations of 73 hips in 59 patients were retrospectively selected and then anonymised, randomised and reviewed by three independent observers (musculoskeletal radiologists). Each MR examination was scored as either A: normal, B: infection, C1: mild MoM disease, C2: moderate MoM disease or C3: severe MoM disease according to pre-defined criteria. Kappa correlation statistics were used to compare the observations. There was substantial agreement among all three observers; the correlation coefficient between the two most experienced observers was {kappa} = 0.78 [95% confidence intervals (CI): 0.68-0.88] and when compared with the least experienced observer coefficients were {kappa} = 0.69 (95% CI: 0.57-0.80) and {kappa} = 0.66 (95% CI: 0.54-0.78). The strongest correlation occurred for grades A, C2 and C3. The weakest correlations occurred for grades B and C1. The grading system described in this study is reliable for evaluating ALVAL in MoM prostheses using MR but is limited in differentiating mild disease from infection. (orig.)

  2. Effects of metals on Legionella pneumophila growth in drinking water plumbing systems

    Energy Technology Data Exchange (ETDEWEB)

    States, S.J.; Conley, L.F.; Ceraso, M.; Stephenson, T.E.; Wolford, R.S.; Wadowsky, R.M.; McNamara, A.M.; Yee, R.B.

    1985-11-01

    Water samples were collected from hospital and institutional hot-water tanks known to have supported L. pneumophila and were analyzed for 23 chemical parameters. The chemical environment of these tanks was found to vary extensively, with the concentrations of certain metals reaching relatively high levels due to corrosion. The effect of various chemical conditions on L. pneumophila growth was then examined by observing its multiplication in a series of tap water samples artificially supplemented with various concentrations of metals. Additionally, growth of L. pneumophila was examined in a more natural setting by monitoring its multiplication in the chemically analyzed hot-water tank samples after sterilization and reinoculation with L. pneumophila. L. Pneumophila and associated microbiota used in these experiments were obtained from a hot-water tank. These strains were maintained in tap water and had never been passaged on agar. The results of the growth studies indicate that although elevated concentrations of a number of metals are toxic, lower levels of certain metals such as iron, zinc, and potassium enhance growth of naturally occurring L. pneumophila. Parallel observations on accompanying non-Legionellaceae bacteria failed to show the same relationship. These findings suggest that metal plumbing components and associated corrosion products are important factors in the survival and growth of L. pneumophila in plumbing systems and may also be important in related habitats such as cooling towers and air-conditioning systems. 1 figure, 2 tables.

  3. Thermographic measurements of the spin Peltier effect in metal/yttrium-iron-garnet junction systems

    Science.gov (United States)

    Daimon, Shunsuke; Uchida, Ken-ichi; Iguchi, Ryo; Hioki, Tomosato; Saitoh, Eiji

    2017-07-01

    The spin Peltier effect (SPE), heat-current generation due to spin-current injection, in various metal (Pt, W, and Au single layers and Pt/Cu bilayer)/ferrimagnetic insulator [yttrium-iron-garnet (YIG)] junction systems has been investigated by means of a lock-in thermography (LIT) method. The SPE is excited by a spin current across the metal/YIG interface, which is generated by applying a charge current to the metallic layer via the spin Hall effect. The LIT method enables the thermal imaging of the SPE free from the Joule-heating contribution. Importantly, we observed spin-current-induced temperature modulation not only in the Pt/YIG and W/YIG systems, but also in the Au/YIG and Pt/Cu/YIG systems, excluding the possible contamination by anomalous Ettingshausen effects due to proximity-induced ferromagnetism near the metal/YIG interface. As demonstrated in our previous study, the SPE signals are confined only in the vicinity of the metal/YIG interface; we buttress this conclusion by reducing a spatial blur due to thermal diffusion in an infrared-emission layer on the sample surface used for the LIT measurements. We also found that the YIG-thickness dependence of the SPE is similar to that of the spin Seebeck effect measured in the same Pt/YIG sample, implying the reciprocal relation between them.

  4. The metal-carbon-fluorine system for improving hydrogen storage by using metal and fluorine with different levels of electronegativity

    Energy Technology Data Exchange (ETDEWEB)

    Im, Ji Sun; Lee, Young-Seak [Department of Fine Chemical Engineering and Applied Chemistry, BK21-E2M, Chungnam National University, Daejeon 305-764 (Korea); Park, Soo-Jin [Department of Chemistry, Inha University, Incheon 402-751 (Korea)

    2009-02-15

    In order to improve the capacity of hydrogen storage using activated carbon nanofibers, metal and fluorine were introduced into the activated carbon nanofibers by electrospinning, heat treatment, and direct fluorination. The pore structure of the samples was developed by the KOH activation process and investigated using nitrogen isotherms and micropore size distribution. The specific surface area and total pore volume approached 2800 m{sup 2}/g and 2.7 cc/g, respectively. Because of the electronegativity gap between the two elements (metal and fluorine), the electron of a hydrogen molecule can be attracted to one side. This reaction effectively guides the hydrogen molecule into the carbon nanofibers. The amount of hydrogen storage was dramatically increased in this metal-carbon-fluorine system; hydrogen content was as high as 3.2 wt%. (author)

  5. Sythesis of rare earth metal - GIC graphite intercalation compound in molten chloride system

    International Nuclear Information System (INIS)

    Ito, Masafumi; Hagiwara, Rika; Ito, Yasuhiko

    1994-01-01

    Graphite intercalation compounds of ytterbium and neodymium have been prepared by interacting graphite and metals in molten chlorides. These rare earth metals can be suspended in molten chlorides in the presence of trichlorides via disproportionation reaction RE(0) + RE(III) = 2RE(II) at lower than 300 degC. Carbides-free compounds are obtained in these systems. (author)

  6. Liquid Metals as Plasma-facing Materials for Fusion Energy Systems: From Atoms to Tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Stone, Howard A. [Princeton Univ., NJ (United States); Koel, Bruce E. [Princeton Univ., NJ (United States); Bernasek, Steven L. [Princeton Univ., NJ (United States); Carter, Emily A. [Princeton Univ., NJ (United States); Debenedetti, Pablo G. [Princeton Univ., NJ (United States); Panagiotopoulos, Athanassios Z. [Princeton Univ., NJ (United States)

    2017-06-23

    The objective of our studies was to advance our fundamental understanding of liquid metals as plasma-facing materials for fusion energy systems, with a broad scope: from atoms to tokamaks. The flow of liquid metals offers solutions to significant problems of the plasma-facing materials for fusion energy systems. Candidate metals include lithium, tin, gallium, and their eutectic combinations. However, such liquid metal solutions can only be designed efficiently if a range of scientific and engineering issues are resolved that require advances in fundamental fluid dynamics, materials science and surface science. In our research we investigated a range of significant and timely problems relevant to current and proposed engineering designs for fusion reactors, including high-heat flux configurations that are being considered by leading fusion energy groups world-wide. Using experimental and theoretical tools spanning atomistic to continuum descriptions of liquid metals, and bridging surface chemistry, wetting/dewetting and flow, our research has advanced the science and engineering of fusion energy materials and systems. Specifically, we developed a combined experimental and theoretical program to investigate flows of liquid metals in fusion-relevant geometries, including equilibrium and stability of thin-film flows, e.g. wetting and dewetting, effects of electromagnetic and thermocapillary fields on liquid metal thin-film flows, and how chemical interactions and the properties of the surface are influenced by impurities and in turn affect the surface wetting characteristics, the surface tension, and its gradients. Because high-heat flux configurations produce evaporation and sputtering, which forces rearrangement of the liquid, and any dewetting exposes the substrate to damage from the plasma, our studies addressed such evaporatively driven liquid flows and measured and simulated properties of the different bulk phases and material interfaces. The range of our studies

  7. Heavy Metal Pollution in a Soil-Rice System in the Yangtze River Region of China.

    Science.gov (United States)

    Liu, Zhouping; Zhang, Qiaofen; Han, Tiqian; Ding, Yanfei; Sun, Junwei; Wang, Feijuan; Zhu, Cheng

    2015-12-22

    Heavy metals are regarded as toxic trace elements in the environment. Heavy metal pollution in soil or rice grains is of increasing concern. In this study, 101 pairs of soil and rice samples were collected from the major rice-producing areas along the Yangtze River in China. The soil properties and heavy metal (i.e., Cd, Hg, Pb and Cr) concentrations in the soil and rice grains were analyzed to evaluate the heavy metal accumulation characteristics of the soil-rice systems. The results showed that the Cd, Hg, Pb and Cr concentrations in the soil ranged from 0.10 to 4.64, 0.01 to 1.46, 7.64 to 127.56, and 13.52 to 231.02 mg·kg(-)¹, respectively. Approximately 37%, 16%, 60% and 70% of the rice grain samples were polluted by Cd, Hg, Pb, and Cr, respectively. The degree of heavy metal contamination in the soil-rice systems exhibited a regional variation. The interactions among the heavy metal elements may also influence the migration and accumulation of heavy metals in soil or paddy rice. The accumulation of heavy metals in soil and rice grains is related to a certain extent to the pH and soil organic matter (SOM). This study provides useful information regarding heavy metal accumulation in soil to support the safe production of rice in China. The findings from this study also provide a robust scientific basis for risk assessments regarding ecological protection and food safety.

  8. Heavy Metal Pollution in a Soil-Rice System in the Yangtze River Region of China

    Science.gov (United States)

    Liu, Zhouping; Zhang, Qiaofen; Han, Tiqian; Ding, Yanfei; Sun, Junwei; Wang, Feijuan; Zhu, Cheng

    2015-01-01

    Heavy metals are regarded as toxic trace elements in the environment. Heavy metal pollution in soil or rice grains is of increasing concern. In this study, 101 pairs of soil and rice samples were collected from the major rice-producing areas along the Yangtze River in China. The soil properties and heavy metal (i.e., Cd, Hg, Pb and Cr) concentrations in the soil and rice grains were analyzed to evaluate the heavy metal accumulation characteristics of the soil-rice systems. The results showed that the Cd, Hg, Pb and Cr concentrations in the soil ranged from 0.10 to 4.64, 0.01 to 1.46, 7.64 to 127.56, and 13.52 to 231.02 mg·kg−1, respectively. Approximately 37%, 16%, 60% and 70% of the rice grain samples were polluted by Cd, Hg, Pb, and Cr, respectively. The degree of heavy metal contamination in the soil-rice systems exhibited a regional variation. The interactions among the heavy metal elements may also influence the migration and accumulation of heavy metals in soil or paddy rice. The accumulation of heavy metals in soil and rice grains is related to a certain extent to the pH and soil organic matter (SOM). This study provides useful information regarding heavy metal accumulation in soil to support the safe production of rice in China. The findings from this study also provide a robust scientific basis for risk assessments regarding ecological protection and food safety. PMID:26703698

  9. Heavy metals in intensive greenhouse vegetable production systems along Yellow Sea of China

    DEFF Research Database (Denmark)

    Hu, Wenyou; Huang, Biao; Tian, Kang

    2017-01-01

    Recently, greenhouse vegetable production (GVP) has grown rapidly and counts a large proportion of vegetable production in China. In this study, the accumulation, health risk and threshold values of selected heavy metals were evaluated systematically. A total of 120 paired soil and vegetable...... relatively high concentrations and transfer factors of heavy metals. The accumulation of heavy metals in soils was affected by soil pH and soil organic matter. The calculated hazard quotients (HQ) of the heavy metals by vegetable consumption decreased in the order of leafy > rootstalk > fruit vegetables...... with hazard index (HI) values of 0.61, 0.33 and 0.26, respectively. The HI values were all below 1, which indicates that there is a low risk of greenhouse vegetable consumption. Soil threshold values (STVs) of heavy metals in GVP system were established according to the health risk assessment. The relatively...

  10. An environment-dependent semi-empirical tight binding model suitable for electron transport in bulk metals, metal alloys, metallic interfaces, and metallic nanostructures. I. Model and validation

    Energy Technology Data Exchange (ETDEWEB)

    Hegde, Ganesh, E-mail: ghegde@purdue.edu; Povolotskyi, Michael; Kubis, Tillmann; Klimeck, Gerhard, E-mail: gekco@purdue.edu [Network for Computational Nanotechnology (NCN), Department of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Boykin, Timothy [Department of Electrical and Computer Engineering, University of Alabama, Huntsville, Alabama (United States)

    2014-03-28

    Semi-empirical Tight Binding (TB) is known to be a scalable and accurate atomistic representation for electron transport for realistically extended nano-scaled semiconductor devices that might contain millions of atoms. In this paper, an environment-aware and transferable TB model suitable for electronic structure and transport simulations in technologically relevant metals, metallic alloys, metal nanostructures, and metallic interface systems are described. Part I of this paper describes the development and validation of the new TB model. The new model incorporates intra-atomic diagonal and off-diagonal elements for implicit self-consistency and greater transferability across bonding environments. The dependence of the on-site energies on strain has been obtained by appealing to the Moments Theorem that links closed electron paths in the system to energy moments of angular momentum resolved local density of states obtained ab initio. The model matches self-consistent density functional theory electronic structure results for bulk face centered cubic metals with and without strain, metallic alloys, metallic interfaces, and metallic nanostructures with high accuracy and can be used in predictive electronic structure and transport problems in metallic systems at realistically extended length scales.

  11. An environment-dependent semi-empirical tight binding model suitable for electron transport in bulk metals, metal alloys, metallic interfaces, and metallic nanostructures. I. Model and validation

    International Nuclear Information System (INIS)

    Hegde, Ganesh; Povolotskyi, Michael; Kubis, Tillmann; Klimeck, Gerhard; Boykin, Timothy

    2014-01-01

    Semi-empirical Tight Binding (TB) is known to be a scalable and accurate atomistic representation for electron transport for realistically extended nano-scaled semiconductor devices that might contain millions of atoms. In this paper, an environment-aware and transferable TB model suitable for electronic structure and transport simulations in technologically relevant metals, metallic alloys, metal nanostructures, and metallic interface systems are described. Part I of this paper describes the development and validation of the new TB model. The new model incorporates intra-atomic diagonal and off-diagonal elements for implicit self-consistency and greater transferability across bonding environments. The dependence of the on-site energies on strain has been obtained by appealing to the Moments Theorem that links closed electron paths in the system to energy moments of angular momentum resolved local density of states obtained ab initio. The model matches self-consistent density functional theory electronic structure results for bulk face centered cubic metals with and without strain, metallic alloys, metallic interfaces, and metallic nanostructures with high accuracy and can be used in predictive electronic structure and transport problems in metallic systems at realistically extended length scales

  12. An environment-dependent semi-empirical tight binding model suitable for electron transport in bulk metals, metal alloys, metallic interfaces, and metallic nanostructures. I. Model and validation

    Science.gov (United States)

    Hegde, Ganesh; Povolotskyi, Michael; Kubis, Tillmann; Boykin, Timothy; Klimeck, Gerhard

    2014-03-01

    Semi-empirical Tight Binding (TB) is known to be a scalable and accurate atomistic representation for electron transport for realistically extended nano-scaled semiconductor devices that might contain millions of atoms. In this paper, an environment-aware and transferable TB model suitable for electronic structure and transport simulations in technologically relevant metals, metallic alloys, metal nanostructures, and metallic interface systems are described. Part I of this paper describes the development and validation of the new TB model. The new model incorporates intra-atomic diagonal and off-diagonal elements for implicit self-consistency and greater transferability across bonding environments. The dependence of the on-site energies on strain has been obtained by appealing to the Moments Theorem that links closed electron paths in the system to energy moments of angular momentum resolved local density of states obtained ab initio. The model matches self-consistent density functional theory electronic structure results for bulk face centered cubic metals with and without strain, metallic alloys, metallic interfaces, and metallic nanostructures with high accuracy and can be used in predictive electronic structure and transport problems in metallic systems at realistically extended length scales.

  13. NONLINEAR COLOR-METALLICITY RELATIONS OF GLOBULAR CLUSTERS. III. ON THE DISCREPANCY IN METALLICITY BETWEEN GLOBULAR CLUSTER SYSTEMS AND THEIR PARENT ELLIPTICAL GALAXIES

    International Nuclear Information System (INIS)

    Yoon, Suk-Jin; Lee, Sang-Yoon; Cho, Jaeil; Kim, Hak-Sub; Chung, Chul; Kim, Sooyoung; Lee, Young-Wook; Blakeslee, John P.; Peng, Eric W.; Sohn, Sangmo T.

    2011-01-01

    One of the conundrums in extragalactic astronomy is the discrepancy in observed metallicity distribution functions (MDFs) between the two prime stellar components of early-type galaxies—globular clusters (GCs) and halo field stars. This is generally taken as evidence of highly decoupled evolutionary histories between GC systems and their parent galaxies. Here we show, however, that new developments in linking the observed GC colors to their intrinsic metallicities suggest nonlinear color-to-metallicity conversions, which translate observed color distributions into strongly peaked, unimodal MDFs with broad metal-poor tails. Remarkably, the inferred GC MDFs are similar to the MDFs of resolved field stars in nearby elliptical galaxies and those produced by chemical evolution models of galaxies. The GC MDF shape, characterized by a sharp peak with a metal-poor tail, indicates a virtually continuous chemical enrichment with a relatively short timescale. The characteristic shape emerges across three orders of magnitude in the host galaxy mass, suggesting a universal process of chemical enrichment among various GC systems. Given that GCs are bluer than field stars within the same galaxy, it is plausible that the chemical enrichment processes of GCs ceased somewhat earlier than that of the field stellar population, and if so, GCs preferentially trace the major, vigorous mode of star formation events in galactic formation. We further suggest a possible systematic age difference among GC systems, in that the GC systems in more luminous galaxies are older. This is consistent with the downsizing paradigm whereby stars of brighter galaxies, on average, formed earlier than those of dimmer galaxies; this additionally supports the similar nature shared by GCs and field stars. Although the sample used in this study (the Hubble Space Telescope Advanced Camera for Surveys/Wide Field Channel, WFPC2, and WFC3 photometry for the GC systems in the Virgo galaxy cluster) confines our

  14. Effects of metal ions on growth, β-oxidation system, and thioesterase activity of Lactococcus lactis.

    Science.gov (United States)

    Li, Liang; Ma, Ying

    2014-10-01

    The effects of divalent metal ions (Ca(2+), Mg(2+), Fe(2+), and Cu(2+)) on the growth, β-oxidation system, and thioesterase activity of Lactococcus lactis were investigated. Different metal ions significantly influenced the growth of L. lactis: Ca(2+) and Fe(2+) accelerated growth, whereas Cu(2+) inhibited growth. Furthermore, Mg(2+) inhibited growth of L. lactis at a low concentration but stimulated growth of L. lactis at a high concentration. The divalent metal ions had significant effects on activity of the 4 key enzymes of the β-oxidation system (acyl-CoA dehydrogenase, enoyl-CoA hydratase, L-3-hydroxyacyl-CoA dehydrogenase, and thiolase) and thioesterase of L. lactis. The activity of acyl-CoA dehydrogenases increased markedly in the presence of Ca(2+) and Mg(2+), whereas it decreased with 1 mmol/L Fe(2+) or 12 mmol/L Mg(2+). All the metal ions could induce activity of enoyl-CoA hydratase. In addition, 12 mmol/L Mg(2+) significantly stimulated activity of L-3-hydroxyacyl-CoA dehydrogenase, and all metal ions could induce activity of thiolase, although thiolase activity decreased significantly when 0.05 mmol/L Cu(2+) was added into M17 broth. Inhibition of thioesterase activity by all 4 metal ions could be reversed by 2 mmol/L Ca(2+). These results help us understand the effect of metal ions on the β-oxidation system and thioesterase activity of Lactococcus lactis. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  15. Analysis of the application of decontamination technologies to radioactive metal waste minimization using expert systems

    Energy Technology Data Exchange (ETDEWEB)

    Bayrakal, Suna [Iowa State Univ., Ames, IA (United States)

    1993-09-30

    Radioactive metal waste makes up a significant portion of the waste currently being sent for disposal. Recovery of this metal as a valuable resource is possible through the use of decontamination technologies. Through the development and use of expert systems a comparison can be made of laser decontamination, a technology currently under development at Ames Laboratory, with currently available decontamination technologies for applicability to the types of metal waste being generated and the effectiveness of these versus simply disposing of the waste. These technologies can be technically and economically evaluated by the use of expert systems techniques to provide a waste management decision making tool that generates, given an identified metal waste, waste management recommendations. The user enters waste characteristic information as input and the system then recommends decontamination technologies, determines residual contamination levels and possible waste management strategies, carries out a cost analysis and then ranks, according to cost, the possibilities for management of the waste. The expert system was developed using information from literature and personnel experienced in the use of decontamination technologies and requires validation by human experts and assignment of confidence factors to the knowledge represented within.

  16. Analysis of the application of decontamination technologies to radioactive metal waste minimization using expert systems

    International Nuclear Information System (INIS)

    Bayrakal, S.

    1993-01-01

    Radioactive metal waste makes up a significant portion of the waste currently being sent for disposal. Recovery of this metal as a valuable resource is possible through the use of decontamination technologies. Through the development and use of expert systems a comparison can be made of laser decontamination, a technology currently under development at Ames Laboratory, with currently available decontamination technologies for applicability to the types of metal waste being generated and the effectiveness of these versus simply disposing of the waste. These technologies can be technically and economically evaluated by the use of expert systems techniques to provide a waste management decision making tool that generates, given an identified metal waste, waste management recommendations. The user enters waste characteristic information as input and the system then recommends decontamination technologies, determines residual contamination levels and possible waste management strategies, carries out a cost analysis and then ranks, according to cost, the possibilities for management of the waste. The expert system was developed using information from literature and personnel experienced in the use of decontamination technologies and requires validation by human experts and assignment of confidence factors to the knowledge represented within

  17. Reversible photochromic system based on rhodamine B salicylaldehyde hydrazone metal complex.

    Science.gov (United States)

    Li, Kai; Xiang, Yu; Wang, Xiaoyan; Li, Ji; Hu, Rongrong; Tong, Aijun; Tang, Ben Zhong

    2014-01-29

    Photochromic molecules are widely applied in chemistry, physics, biology, and materials science. Although a few photochromic systems have been developed before, their applications are still limited by complicated synthesis, low fatigue resistance, or incomplete light conversion. Rhodamine is a class of dyes with excellent optical properties including long-wavelength absorption, large absorption coefficient, and high photostability in its ring-open form. It is an ideal chromophore for the development of new photochromic systems. However, known photochromic rhodamine derivatives, such as amides, exhibit only millisecond lifetimes in their colored ring-open forms, making their application very limited and difficult. In this work, rhodamine B salicylaldehyde hydrazone metal complex was found to undergo intramolecular ring-open reactions upon UV irradiation, which led to a distinct color and fluorescence change both in solution and in solid matrix. The complex showed good fatigue resistance for the reversible photochromism and long lifetime for the ring-open state. Interestingly, the thermal bleaching rate was tunable by using different metal ions, temperatures, solvents, and chemical substitutions. It was proposed that UV light promoted isomerization of the rhodamine B derivative from enol-form to keto-form, which induced ring-opening of the rhodamine spirolactam in the complex to generate color. The photochromic system was successfully applied for photoprinting and UV strength measurement in the solid state. As compared to other reported photochromic molecules, the system in this study has its advantages of facile synthesis and tunable thermal bleaching rate, and also provides new insights into the development of photochromic materials based on metal complex and spirolactam-containing dyes.

  18. Heavy metals in system «Delta of Volga - Northern Caspian Sea

    Directory of Open Access Journals (Sweden)

    E. V. Ostrovscaya

    2008-01-01

    Full Text Available It is displayed that the composition of heavy metals compounds in water and suspensions in the area of marine and riverine waters mixing undergo natural changes due to sedimentation and transformation. The system “Volga Delta – North Caspian” as a geochemical barrier hampers the transfer of toxic heavy metals forms from the sea to the river, although the content of toxic iron and manganese forms at the marine border of coastal waters can reach up to 30% of total concentration.

  19. Optimization of film synthesized rare earth transition metal permanent magnet systems

    International Nuclear Information System (INIS)

    Cadieu, F.J.

    1990-01-01

    This report reviews work on the optimization of film synthesized rare earth transition metal permanent magnet systems. Topics include: high coercivity in Sm-Fe-Ti-V, Sm-Fe-V, and two element systems; ThMn 12 type pseudobinary SmFe 12 - X T X ; and sputter process control for the synthesis of precisely textured RE-TM magnetic films. (JL)

  20. MICROFABRICATED ELECTROCHEMICAL ANALYSIS SYSTEM FOR HEAVY METAL DETECTION. (R825511C047)

    Science.gov (United States)

    A low power, hand-held system has been developed for the measurement of heavy metal ions in aqueous solutions. The system consists of an electrode array sensor, a high performance single chip potentiostat and a microcontroller circuit. The sensor is a microfabricated array of ...

  1. Viscoelastic analysis of a dental metal-ceramic system

    Science.gov (United States)

    Özüpek, Şebnem; Ünlü, Utku Cemal

    2012-11-01

    Porcelain-fused-to-metal (PFM) restorations used in prosthetic dentistry contain thermal stresses which develop during the cooling phase after firing. These thermal stresses coupled with the stresses produced by mechanical loads may be the dominant reasons for failures in clinical situations. For an accurate calculation of these stresses, viscoelastic behavior of ceramics at high temperatures should not be ignored. In this study, the finite element technique is used to evaluate the effect of viscoelasticity on stress distributions of a three-point flexure test specimen, which is the current international standard, ISO 9693, to characterize the interfacial bond strength of metal-ceramic restorative systems. Results indicate that the probability of interfacial debonding due to normal tensile stress is higher than that due to shear stress. This conclusion suggests modification of ISO 9693 bond strength definition from one in terms of the shear stress only to that accounting for both normal and shear stresses.

  2. Electrical Control of Metallic Heavy-Metal-Ferromagnet Interfacial States

    Science.gov (United States)

    Bi, Chong; Sun, Congli; Xu, Meng; Newhouse-Illige, Ty; Voyles, Paul M.; Wang, Weigang

    2017-09-01

    Voltage-control effects provide an energy-efficient means of tailoring material properties, especially in highly integrated nanoscale devices. However, only insulating and semiconducting systems can be controlled so far. In metallic systems, there is no electric field due to electron screening effects and thus no such control effect exists. Here, we demonstrate that metallic systems can also be controlled electrically through ionic rather than electronic effects. In a Pt /Co structure, the control of the metallic Pt /Co interface can lead to unprecedented control effects on the magnetic properties of the entire structure. Consequently, the magnetization and perpendicular magnetic anisotropy of the Co layer can be independently manipulated to any desired state, the efficient spin toques can be enhanced about 3.5 times, and the switching current can be reduced about one order of magnitude. This ability to control a metallic system may be extended to control other physical phenomena.

  3. Development of engineering parameters for the design of metal biosorption waste treatment systems

    Energy Technology Data Exchange (ETDEWEB)

    Graham, W.S.

    1991-12-03

    Untreated landfill leachates and wastes from metal plating and mining operations are sources of environmental contamination by heavy metals. Because of their toxicity and potential for accumulation, the discharge of heavy metals must be controlled. Standard physical and chemical treatments used to remove metals from wastes such as concentration by electro-precipitation, ion exchange, solvent extraction, evaporative recovery, and conventional precipitation, are usually expensive and produce high quantities of sludge. Biosorption is the removal of metals from aqueous solutions by microorganisms. It is called biosorption rather than bioadsorption or bioaccumulation because the mechanisms of removal are not restricted to adsorption or metabolic uptake and so the more general term is preferable and has come to be accepted. In this thesis the focus is one two microorganisms and two metals. However, the possible combinations of conditions such as pH, relative metal molarities, time of contact, and organism are numerous. These experiments are designed to provide optimized parameters to facilitate the design of a functioning biosorption system. The two metals chosen for study are copper and lead in aqueous solution. The two types of microorganisms chosen for testing include an actinomycete and a fungus. The purpose of this research is to identify the significant engineering parameters to be evaluated include reaction rates, equilibrium partitioning of metal ions between those in solution and those removed to the cells, optimum pH for achieving the removal or recovery goal, and biosorption selectivity for one metal over another.

  4. Recent Advances in Antimicrobial Hydrogels Containing Metal Ions and Metals/Metal Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Fazli Wahid

    2017-11-01

    Full Text Available Recently, the rapid emergence of antibiotic-resistant pathogens has caused a serious health problem. Scientists respond to the threat by developing new antimicrobial materials to prevent or control infections caused by these pathogens. Polymer-based nanocomposite hydrogels are versatile materials as an alternative to conventional antimicrobial agents. Cross-linking of polymeric materials by metal ions or the combination of polymeric hydrogels with nanoparticles (metals and metal oxide is a simple and effective approach for obtaining a multicomponent system with diverse functionalities. Several metals and metal oxides such as silver (Ag, gold (Au, zinc oxide (ZnO, copper oxide (CuO, titanium dioxide (TiO2 and magnesium oxide (MgO have been loaded into hydrogels for antimicrobial applications. The incorporation of metals and metal oxide nanoparticles into hydrogels not only enhances the antimicrobial activity of hydrogels, but also improve their mechanical characteristics. Herein, we summarize recent advances in hydrogels containing metal ions, metals and metal oxide nanoparticles with potential antimicrobial properties.

  5. Accumulation of heavy metals in soil-crop systems: a review for wheat and corn.

    Science.gov (United States)

    Wang, Shiyu; Wu, Wenyong; Liu, Fei; Liao, Renkuan; Hu, Yaqi

    2017-06-01

    The health risks arising from heavy metal pollution (HMP) in agricultural soils have attracted global attention, and research on the accumulation of heavy metals in soil-plant systems is the basis for human health risk assessments. This review studied the accumulation of seven typical heavy metals-Cd, Cr, As, Pb, Hg, Cu, and Zn-in soil-corn and soil-wheat systems. The findings indicated that, in general, wheat was more likely to accumulate heavy metals than corn. Bioconcentration factor (BCF) of the seven heavy metals in wheat and corn grains decreased exponentially with their average concentrations in soil. The seven heavy metals were ranked as follows, in ascending order of accumulation in corn grains: Pb < Cr < Zn < As < Cu < Cd

  6. Surface analysis of model systems: From a metal-graphite interface to an intermetallic catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kwolek, Emma J. [Iowa State Univ., Ames, IA (United States)

    2016-10-25

    This thesis summarizes research completed on two different model systems. In the first system, we investigate the deposition of the elemental metal dysprosium on highly-oriented pyrolytic graphite (HOPG) and its resulting nucleation and growth. The goal of this research is to better understand the metal-carbon interactions that occur on HOPG and to apply those to an array of other carbon surfaces. This insight may prove beneficial to developing and using new materials for electronic applications, magnetic applications and catalysis.

  7. Heavy Metal Pollution in a Soil-Rice System in the Yangtze River Region of China

    Directory of Open Access Journals (Sweden)

    Zhouping Liu

    2015-12-01

    Full Text Available Heavy metals are regarded as toxic trace elements in the environment. Heavy metal pollution in soil or rice grains is of increasing concern. In this study, 101 pairs of soil and rice samples were collected from the major rice-producing areas along the Yangtze River in China. The soil properties and heavy metal (i.e., Cd, Hg, Pb and Cr concentrations in the soil and rice grains were analyzed to evaluate the heavy metal accumulation characteristics of the soil-rice systems. The results showed that the Cd, Hg, Pb and Cr concentrations in the soil ranged from 0.10 to 4.64, 0.01 to 1.46, 7.64 to 127.56, and 13.52 to 231.02 mg·kg−1, respectively. Approximately 37%, 16%, 60% and 70% of the rice grain samples were polluted by Cd, Hg, Pb, and Cr, respectively. The degree of heavy metal contamination in the soil-rice systems exhibited a regional variation. The interactions among the heavy metal elements may also influence the migration and accumulation of heavy metals in soil or paddy rice. The accumulation of heavy metals in soil and rice grains is related to a certain extent to the pH and soil organic matter (SOM. This study provides useful information regarding heavy metal accumulation in soil to support the safe production of rice in China. The findings from this study also provide a robust scientific basis for risk assessments regarding ecological protection and food safety.

  8. Ab initio study of the atomic motion in liquid metal surfaces: comparison with Lennard-Jones systems

    International Nuclear Information System (INIS)

    Gonzalez, Luis E; Gonzalez, David J

    2006-01-01

    It is established that liquid metals exhibit surface layering at the liquid-vapour interface, while dielectric simple systems, like those interacting through Lennard-Jones potentials, show a monotonic decay from the liquid density to that of the vapour. First principles molecular dynamics simulations of the free liquid surface of several liquid metals (Li, Na, K, Rb, Cs, Mg, Ba, Al, Tl and Si), and the Na 3 K 7 alloy near their triple points have been performed in order to study the atomic motion at the interface, mainly at the outer layer. Comparison with the results of classical molecular dynamics simulations of a Lennard-Jones system shows interesting differences and similarities. The probability distribution function of the time of residence in a layer shows a peak at very short times and a long-lasting tail. The mean residence time in a layer increases when approaching the interfacial region, slightly in the Lennard-Jones system but strongly in the metallic systems. The motion within the layers, parallel to the interface, can be described as diffusion enhanced (strongly in the case of the outermost layer) with respect to the bulk, for both types of systems, despite its reduced dimensionality in metals

  9. The Behavior and Effects of the Noble Metals in the DWPF Melter System

    International Nuclear Information System (INIS)

    Smith, M.E.; Bickford, D.F.

    1997-01-01

    Governments worldwide have committed to stabilization of high-level nuclear waste (HLW) by vitrification to a durable glass form for permanent disposal. All of these nuclear wastes contain the fission-product noble metals: ruthenium, rhodium, and palladium. SRS wastes also contain natural silver from iodine scrubbers. Closely associated with the noble metals are the fission products selenium and tellurium which are chemical analogs of sulfur and which combine with noble metals to influence their behavior and properties. Experience has shown that these melt insoluble metals and their compounds tend to settle to the floor of Joule-heated ceramic melters. In fact, almost all of the major research and production facilities have experienced some operational problem which can be associated with the presence of dense accumulations of these relatively conductive metals and/or their compounds. In most cases, these deposits have led to a loss of production capability, in some cases, to the point that melter operation could not continue. HLW nuclear waste vitrification facilities in the United States are the Department of Energy's Defense Waste Processing Facility (DWPF) at the Savannah River Site, the planned Hanford Waste Vitrification Plant (HWVP) at the Hanford Site and the operating West Valley Demonstration Project (WVDP) at West Valley, NY. The Integrated DWPF Melter System (IDMS) is a vitrification test facility at the Savannah River Technology Center (SRTC). It was designed and constructed to provide an engineering-scale representation of the DWPF melter and its associated feed preparation and off-gas treatment systems. An extensive noble metals testing program was begun in 1990. The objectives of this task were to explore the effects of the noble metals on the DWPF melter feed preparation and waste vitrification processes. This report focuses on the vitrification portion of the test program

  10. Electronic annealing Fermi operator expansion for DFT calculations on metallic systems

    Science.gov (United States)

    Aarons, Jolyon; Skylaris, Chris-Kriton

    2018-02-01

    Density Functional Theory (DFT) calculations with computational effort which increases linearly with the number of atoms (linear-scaling DFT) have been successfully developed for insulators, taking advantage of the exponential decay of the one-particle density matrix. For metallic systems, the density matrix is also expected to decay exponentially at finite electronic temperature and linear-scaling DFT methods should be possible by taking advantage of this decay. Here we present a method for DFT calculations at finite electronic temperature for metallic systems which is effectively linear-scaling (O(N)). Our method generates the elements of the one-particle density matrix and also finds the required chemical potential and electronic entropy using polynomial expansions. A fixed expansion length is always employed to generate the density matrix, without any loss in accuracy by the application of a high electronic temperature followed by successive steps of temperature reduction until the desired (low) temperature density matrix is obtained. We have implemented this method in the ONETEP linear-scaling (for insulators) DFT code which employs local orbitals that are optimised in situ. By making use of the sparse matrix machinery of ONETEP, our method exploits the sparsity of Hamiltonian and density matrices to perform calculations on metallic systems with computational cost that increases asymptotically linearly with the number of atoms. We demonstrate the linear-scaling computational cost of our method with calculation times on palladium nanoparticles with up to ˜13 000 atoms.

  11. Conceptual study of a complementary scram system for liquid metal cooled nuclear reactors

    International Nuclear Information System (INIS)

    Vanmaercke, S.; Van den Eynde, G.; Tijskens, E.; Bartosiewicz, Y.

    2009-01-01

    GEN-IV reactors promise higher safety and reliability as one of the major improvements over previous generations of reactors. To achieve that, all GEN-IV reactor concepts require two completely independent shutdown systems that rely on different operating principles. For liquid metal cooled reactors the first system is an absorber-rod based solution. The second system that by requirement should rely on another principle, is however quite a challenge to design. The second system used in current PWR reactors is to dissolve a neutron absorber, boric acid, into the primary coolant. This method cannot be used in liquid metal cooled reactors because of the high cost of cleaning the coolant. In this paper an overview of the existing literature on scram systems is given, each with their advantages and limitations. A promising new concept is also presented. This concept leads to a totally passive self activating device using small absorbing particles that flow into a dedicated channel to shutdown the reactor. The system consists of tubes filled with particles of an absorber material. During normal operation, these particles are kept above the active core by means of a metallic seal. In case of an accident, the system is activated by the temperature increase in the coolant. This leads to melting of the metal seal. The ongoing work conducted at SCK·CEN and UCL/TERM aims at assessing the reliability of this new concept both experimentally and numerically. This study is multidisciplinary as neutronic and thermal hydraulics issues are tackled. Most challenging is however the thermal hydraulics related to understanding and predicting the liberation and flow of the absorber particles during a shutdown. Simple experiments are envisaged to compare to numerical simulations using the Discrete Element Method for simulating the particles. In a later stage this will be coupled with Smoothed Particles Hydrodynamics for simulating the melting of the seal. Some preliminary experimental and

  12. Investigation of two-phase liquid-metal magnetohydrodynamic power systems

    International Nuclear Information System (INIS)

    Amend, W.E.; Fabris, G.; Cutting, J.

    1975-01-01

    A two-phase Liquid-Metal MHD (LMMHD) system is under development at the Argonne National Laboratory, and results are presented for detailed cycle analysis and systems studies, the experimental facility, and the thermal and magneto fluid mechanics problems encountered. The studies indicate that the LMMHD cycle will operate efficiently in the temperature range of 1000-1600 0 F (50 percent efficiency with a maximum cycle temperature of 1600 0 F) and is therefore potentially compatible with many advanced heat sources under development such as the LMFBR, fluidized-bed coal combustor, HTGCR and the fusion reactor. Of special interest is the coupling to the LMFBR thereby eliminating the costly, potentially hazardous liquid-metal/water interface. The results of detailed parametric studies of the heat transfer interfaces between an LMMHD power cycle and an LMFBR and a steam bottoming plant are described. Experimental evaluation of the two-phase LMMHD generator was performed in an ambient temperature NaK--N 2 facility at ANL. Results of these experiments, performed to determine the operating characteristics of the device as a function of the various independent parameters and to investigate two-phase flow, are given. (U.S.)

  13. High-Pressure Thermodynamic Properties of f-electron Metals, Transition Metal Oxides, and Half-Metallic Magnets

    International Nuclear Information System (INIS)

    Richard T. Scalettar; Warren E. Pickett

    2005-01-01

    This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (1) Mott transitions in transition metal oxides, (2) magnetism in half-metallic compounds, and (3) large volume-collapse transitions in f-band metals

  14. High-Pressure Thermodynamic Properties of f-electron Metals, Transition Metal Oxides, and Half-Metallic Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Scalettar, Richard T.; Pickett, Warren E.

    2004-07-01

    This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (1) Mott transitions in transition metal oxides, (2) magnetism in half-metallic compounds, and (3) large volume-collapse transitions in f-band metals.

  15. High-Pressure Thermodynamic Properties of f-electron Metals, Transition Metal Oxides, and Half-Metallic Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Richard T. Scalettar; Warren E. Pickett

    2005-08-02

    This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (i) Mott transitions in transition metal oxides, (ii) magnetism in half-metallic compounds, and (iii) large volume-collapse transitions in f-band metals.

  16. Assessment of heavy metals in loose deposits in drinking water distribution system.

    Science.gov (United States)

    Liu, Quanli; Han, Weiqiang; Han, Bingjun; Shu, Min; Shi, Baoyou

    2018-06-09

    Heavy metal accumulation and potential releases from loose deposits in drinking water distribution system (DWDS) can have critical impacts on drinking water safety, but the associated risks have not been sufficiently evaluated. In this work, the potential biological toxicity of heavy metals in loose deposits was calculated based on consensus-based sediment quality guidelines, and the effects of some of the main water quality parameters, such as the pH and bicarbonate and phosphate content, on the release behaviors of pre-accumulated heavy metals were investigated. The results showed that heavy metals (Cu, As, Cr, Pb, and Cd) significantly accumulated in all the samples, but the contents of the heavy metals were multiple magnitudes lower than the Fe and Mn contents. The potential biotoxicity of As and Cu was relatively high, but the biotoxicity of Cd was negligible. The water quality can significantly influence the release of heavy metals from loose deposits. As the pH increased from 7.0 to 9.0, the release of As and Cr obviously increased. The release of As, Cu, Pb, and Cr also accelerated with the addition of phosphate (from 1 to 5 mg/L). In contrast to the trends for the pH and phosphate, variations in the bicarbonate content did not have a significant influence on the release of As and Cr. The release ratios of heavy metals in the samples were very low, and there was not a correlation between the release rate of the heavy metals in the loose deposits and their potential biotoxicity.

  17. Classification of Metal-Deficient Dwarfs in the Vilnius Photometric System

    Directory of Open Access Journals (Sweden)

    Lazauskaitė R.

    2003-12-01

    Full Text Available Methods used for the quantitative classification of metal-deficient stars in the Vilnius photometric system are reviewed. We present a new calibration of absolute magnitudes for dwarfs and subdwarfs, based on Hipparcos parallaxes. The new classification scheme is applied to a sample of Population II visual binaries.

  18. Fatal Cobalt Toxicity after a Non-Metal-on-Metal Total Hip Arthroplasty

    Directory of Open Access Journals (Sweden)

    Rinne M. Peters

    2017-01-01

    Full Text Available This case illustrates the potential for systemic cobalt toxicity in non-metal-on-metal bearings and its potentially devastating consequences. We present a 71-year-old male with grinding sensations in his right hip following ceramic-on-ceramic total hip arthroplasty (THA. After diagnosing a fractured ceramic liner, the hip prosthesis was revised into a metal-on-polyethylene bearing. At one year postoperatively, X-rays and MARS-MRI showed a fixed reversed hybrid THA, with periarticular densities, flattening of the femoral head component, and a pattern of periarticular metal wear debris and pseudotumor formation. Before revision could take place, the patient was admitted with the clinical picture of systemic cobalt toxicity, supported by excessively high serum cobalt and chromium levels, and ultimately died. At autopsy dilated cardiomyopathy as cause of death was hypothesized. A third body wear reaction between ceramic remnants and the metal femoral head very likely led to excessive metal wear, which contributed systemic cobalt toxicity leading to neurotoxicity and heart failure. This case emphasizes that fractured ceramic-on-ceramic bearings should be revised to ceramic-on-ceramic or ceramic-on-polyethylene bearings, but not to metal-on-polyethylene bearings. We aim to increase awareness among orthopedic surgeons for clinical clues for systemic cobalt intoxication, even when there is no metal-on-metal bearing surface.

  19. PARTITIONING OF THE REFRACTORY METALS, NICKEL AND CHROMIUM, IN COMBUSTION SYSTEMS

    Science.gov (United States)

    The partitioning of nickel (Ni) and Chromium (Cr) in combustion systems was investigated theoretically and experimentally. In comparison to other volatile and semi-volatile metals, both Ni and Cr are usually considered to be refractory (non-volatile). Theoretical predictions ba...

  20. Thin films of metal-organic compounds and metal nanoparticle

    Indian Academy of Sciences (India)

    Thin films of metal-organic compounds and metal nanoparticle-embedded polymers for nonlinear optical applications. S Philip Anthony Shatabdi Porel D ... Thin films based on two very different metal-organic systems are developed and some nonlinear optical applications are explored. A family of zinc complexes which ...

  1. Multi-Scale Modeling of Microstructural Evolution in Structural Metallic Systems

    Science.gov (United States)

    Zhao, Lei

    Metallic alloys are a widely used class of structural materials, and the mechanical properties of these alloys are strongly dependent on the microstructure. Therefore, the scientific design of metallic materials with superior mechanical properties requires the understanding of the microstructural evolution. Computational models and simulations offer a number of advantages over experimental techniques in the prediction of microstructural evolution, because they can allow studies of microstructural evolution in situ, i.e., while the material is mechanically loaded (meso-scale simulations), and bring atomic-level insights into the microstructure (atomistic simulations). In this thesis, we applied a multi-scale modeling approach to study the microstructural evolution in several metallic systems, including polycrystalline materials and metallic glasses (MGs). Specifically, for polycrystalline materials, we developed a coupled finite element model that combines phase field method and crystal plasticity theory to study the plasticity effect on grain boundary (GB) migration. Our model is not only coupled strongly (i.e., we include plastic driving force on GB migration directly) and concurrently (i.e., coupled equations are solved simultaneously), but also it qualitatively captures such phenomena as the dislocation absorption by mobile GBs. The developed model provides a tool to study the microstructural evolution in plastically deformed metals and alloys. For MGs, we used molecular dynamics (MD) simulations to investigate the nucleation kinetics in the primary crystallization in Al-Sm system. We calculated the time-temperature-transformation curves for low Sm concentrations, from which the strong suppressing effect of Sm solute on Al nucleation and its influencing mechanism are revealed. Also, through the comparative analysis of both Al attachment and Al diffusion in MGs, it has been found that the nucleation kinetics is controlled by interfacial attachment of Al, and that

  2. Remediation Performance and Mechanism of Heavy Metals by a Bottom Up Activation and Extraction System Using Multiple Biochemical Materials.

    Science.gov (United States)

    Xiao, Kemeng; Li, Yunzhen; Sun, Yang; Liu, Ruyue; Li, Junjie; Zhao, Yun; Xu, Heng

    2017-09-13

    Soil contamination with heavy metals has caused serious environmental problems and increased the risks to humans and biota. Herein, we developed an effective bottom up metals removal system based on the synergy between the activation of immobilization metal-resistant bacteria and the extraction of bioaccumulator material (Stropharia rugosoannulata). In this system, the advantages of biochar produced at 400 °C and sodium alginate were integrated to immobilize bacteria. Optimized by response surface methodology, the biochar and bacterial suspension were mixed at a ratio of 1:20 (w:v) for 12 h when 2.5% sodium alginate was added to the mixture. Results demonstrated that the system significantly increased the proportion of acid soluble Cd and Cu and improved the soil microecology (microbial counts, soil respiration, and enzyme activities). The maximum extractions of Cd and Cu were 8.79 and 77.92 mg kg -1 , respectively. Moreover, details of the possible mechanistic insight into the metal removal are discussed, which indicate positive correlation with the acetic acid extractable metals and soil microecology. Meanwhile, the "dilution effect" in S. rugosoannulata probably plays an important role in the metal removal process. Furthermore, the metal-resistant bacteria in this system were successfully colonized, and the soil bacteria community were evaluated to understand the microbial diversity in metal-contaminated soil after remediation.

  3. Microbial biofilms control economic metal mobility in an acid-sulfate hydrothermal system

    Science.gov (United States)

    Phillips-Lander, C. M.; Roberts, J. A.; Hernandez, W.; Mora, M.; Fowle, D. A.

    2012-12-01

    Trace metal cycling in hydrothermal systems has been the subject of a variety of geochemical and economical geology studies. Typically in these settings these elements are sequestered in sulfide and oxide mineral fractions, however in near-surface low-temperature environments organic matter and microorganisms (typically in mats) have been implicated in their mobility through sorption. Here we specifically examine the role of microbial biofilms on metal partitioning in an acid-sulfate hydrothermal system. We studied the influence of microorganisms and microbial biofilms on trace metal adsorption in Pailas de Aguas I, an acid-sulfate hot spring on the southwest flank of Rincon de la Vieja, a composite stratovolcano in the Guanacaste Province, Costa Rica. Spring waters contain high suspended loads, and are characterized by high T (79.6-89.3oC), low pH (2.6-4), and high ionic strengths (I= 0.5-0.8). Waters contain high concentrations of the biogeochemically active elements Fe (4-6 mmol/l) and SO42- (38 mmol/l), but PO43- are below detection limits (bdl). Silver, Ni, and Mo concentrations are bdl; however other trace metals are present in solution in concentrations of 0.1-0.2 mg/l Cd, 0.2-0.4 mg/l Cr and V, 0.04-1 mg/l Cu,. Preliminary 16S rRNA analyses of microorganisms in sediments reveal several species of algae, including Galderia sp., Cyanidium sp, γ-proteobacteria, Acidithiobacillus caldus, Euryarcheota, and methanogens. To evaluate microbial biofilms' impact on trace metal mobility we analyzed a combination of suspended, bulk and biofilm associated sediment samples via X-ray diffraction (XRD) and trace element sequential extractions (SE). XRD analysis indicated all samples were primarily composed of Fe/Al clay minerals (nontronite, kaolinite), 2- and 6-line ferrihydrite, goethite, and hematite, quartz, and opal-α. SE showed the highest concentrations of Cu, Mo, and V were found in the suspended load. Molybdenum was found primarily in the residual and organic

  4. Theoretical bases on thermal stability of layered metallic systems

    International Nuclear Information System (INIS)

    Kadyrzhanov, K.K.; Rusakov, V.S.; Turkebaev, T.Eh.; Zhankadamova, A.M.; Ensebaeva, M.Z.

    2003-01-01

    The paper is dedicated to implementation of the theoretical bases for layered metallic systems thermal stabilization. The theory is based on the stabilization mechanism expense of the intermediate two-phase field formation. As parameters of calculated model are coefficients of mutual diffusion and inclusions sizes of generated phases in two-phase fields. The stabilization time dependence for beryllium-iron (Be (1.1 μm)-Fe(5.5 μm)) layered system from iron and beryllium diffusion coefficients, and inclusions sizes is shown as an example. Conclusion about possible mechanisms change at transition from microscopic consideration to the nano-crystal physics level is given

  5. How much metal can you get? Quantified mass balancing of base metal release during epidosite zone alteration in ophiolite-hosted VMS systems

    OpenAIRE

    Jowitt, Simon M.; Jenkin, Gawen R.T.; Coogan, Laurence A.; Naden, Jon

    2009-01-01

    Understanding source-deposit relationships in VMS systems is important for mineral exploration and to increase knowledge of seafloor hydrothermal processes and ocean–crust fluxes. Although it is known that metals are stripped from oceanic crust by hydrothermal fluids and are partly redeposited in orebodies, some aspects are poorly understood. It has been proposed that metal-depleted epidosites (epidote–quartz–chlorite–Fe-oxide–titanite units within sheeted dyke complexes) were the source rock...

  6. Metal-hydrogen systems with an exceptionally large and tunable thermodynamic destabilization

    NARCIS (Netherlands)

    Ngene, Peter; Longo, Alessandro; Mooij, L.P.A.; Bras, Wim; Dam, B.

    2017-01-01

    Hydrogen is a key element in the energy transition. Hydrogen-metal systems have been studied for various energy-related applications, e.g., for their use in reversible hydrogen storage, catalysis, hydrogen sensing, and rechargeable batteries. These applications depend strongly on the

  7. Study on liquid-metal MHD power generation system with two-phase natural circulation. Applicability to fast reactor conditions

    International Nuclear Information System (INIS)

    Saito, Masaki

    2000-03-01

    Feasibility study of the liquid-metal MHD power generation system combined with the high-density two-phase natural circulation has been performed for the applicability to the simple, autonomic energy conversion system of the liquid-metal cooled fast reactor. The present system has many promising aspects not only in the energy conversion process, but also in safety and economical improvements of the liquid-metal cooled fast reactor. For example, the high cycle efficiency can be expected because of the similarity of the present cycle to the Ericsson cycle. Sodium-Water Interaction problem can be excluded by proper combination of the working fluids. As the economical feature, the present system is so simple that the liquid-metal main circular pump, the steam turbine generator, and even the steam generator can be excluded if the thermodynamic working fluid is injected directly into the high temperature liquid metal MHD working fluid. In addition, the present system has the potential to be applied to various heat sources including solar energy because of the high flexibility of the operation temperature. In the present paper, as the first step of the feasibility study, the cycle analyses were performed to examine the effects of the main system parameters on the fundamental characteristics of the system. It is found that the cycle efficiency of the present system is enough competitive with that of the conventional steam turbine system. It is, however, found that the cycle efficiency depends strongly on the gas-liquid slip ratio in the two-phase flow channel. As the conclusions, it is recommended to perform experimental study to obtain the fundamental data, such as the gas-liquid slip ratio in the high-density liquid-metal two-phase natural circulation. (author)

  8. Electrical Investigation of Metal-Olivine Systems and Application to the Deep Interior of Mercury

    Science.gov (United States)

    Zhang, Zhou; Pommier, Anne

    2017-12-01

    We report electrical conductivity measurements on metal-olivine systems at about 5 and 6 GPa and up to 1,675°C in order to investigate the electrical properties of core-mantle boundary (CMB) systems. Electrical experiments were conducted in the multianvil apparatus using the impedance spectroscopy technique. The samples are composed of one metal layer (Fe, FeS, FeSi2, or Fe-Ni-S-Si) and one polycrystalline olivine layer, with the metal:olivine ratio ranging from 1:0.7 to 1:9.2. For all samples, we observe that the bulk electrical conductivity increases with temperature from 10-2.5 to 101.8 S/m, which is higher than the conductivity of polycrystalline olivine but lower than the conductivity of the pure metal phase at similar conditions. In some experiments, a conductivity jump is observed at the temperature corresponding to the melting temperature of the metallic phase. Both the metal:olivine ratio and the metal phase geometry control the electrical conductivity of the two-layer samples. By combining electrical results, textural analyses of the samples, and previous studies of the structure and composition of Mercury's interior, we propose an electrical profile of the deep interior of the planet that accounts for a layered CMB-outer core structure. The electrical model agrees with existing conductivity estimates of Mercury's lower mantle and CMB using magnetic observations and thermodynamic calculations, and thus, supports the hypothesis of a layered CMB-outermost core structure in the present-day interior of Mercury. We propose that the layered CMB-outer core structure is possibly electrically insulating, which may influence the planet's structure and cooling history.

  9. System and process for production of magnesium metal and magnesium hydride from magnesium-containing salts and brines

    Science.gov (United States)

    McGrail, Peter B.; Nune, Satish K.; Motkuri, Radha K.; Glezakou, Vassiliki-Alexandra; Koech, Phillip K.; Adint, Tyler T.; Fifield, Leonard S.; Fernandez, Carlos A.; Liu, Jian

    2016-11-22

    A system and process are disclosed for production of consolidated magnesium metal products and alloys with selected densities from magnesium-containing salts and feedstocks. The system and process employ a dialkyl magnesium compound that decomposes to produce the Mg metal product. Energy requirements and production costs are lower than for conventional processing.

  10. First row transition metal atoms embedded in multivacancies in a rippled graphene system

    Science.gov (United States)

    Mombrú, Dominique; Faccio, Ricardo; Mombrú, Alvaro W.

    2018-03-01

    Ab-initio calculations based on density functional theory (DFT) have been performed to study systems where a first row transition metal atom is embedded in a rippled graphene due to the existence of an 8-order multivacancy. In addition to these cases, also the inclusion of a zinc atom, with a 3d10 electron configuration, was also studied. Structural distortions and magnetic response for each system were studied. A correlation was found for the magnitude of the rippling and the distortion in the vacancy. Variation in the trends was found for Cu and Zn cases, which were explained on the basis of the filling of the 3dx2-y2 orbital. All the systems exhibit lower magnetic moment in comparison to the metal-less system. The quenching of the magnetic moment due to the carbon atoms in the vacancy is observed for Sc and Cu.

  11. Environmental dynamics of metal oxide nanoparticles in heterogeneous systems: A review

    International Nuclear Information System (INIS)

    Joo, Sung Hee; Zhao, Dongye

    2017-01-01

    Highlights: • Influence of contaminants on the mobility of metal oxide nanoparticles (MNPs). • Synergistic effects of MNPs in the presence of contaminants. • Effect of environmental factors on the transformed MNPs. • Research direction on the toxicity modeling assessment of heterogeneous systems. - Abstract: Metal oxide nanoparticles (MNPs) have been used for many purposes including water treatment, health, cosmetics, electronics, food packaging, and even food products. As their applications continue to expand, concerns have been mounting about the environmental fate and potential health risks of the nanoparticles in the environment. Based on the latest information, this review provides an overview of the factors that affect the fate, transformation and toxicity of MNPs. Emphasis is placed on the effects of various aquatic contaminants under various environmental conditions on the transformation of metal oxides and their transport kinetics – both in homogeneous and heterogeneous systems – and the effects of contaminants on the toxicity of MNPs. The presence of existing contaminants decreases bioavailability through hetero-aggregation, sorption, and/or complexation upon an interaction with MNPs. Contaminants also influence the fate and transport of MNPs and exhibit their synergistic toxic effects that contribute to the extent of the toxicity. This review will help regulators, engineers, and scientists in this field to understand the latest development on MNPs, their interactions with aquatic contaminants as well as the environmental dynamics of their fate and transformation. The knowledge gap and future research needs are also identified, and the challenges in assessing the environmental fate and transport of nanoparticles in heterogeneous systems are discussed.

  12. Environmental dynamics of metal oxide nanoparticles in heterogeneous systems: A review

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Sung Hee, E-mail: s.joo1@miami.edu [Department of Civil, Architectural, and Environmental Engineering, University of Miami, 1251 Memorial Dr. McArthur Engineering Building, Coral Gables, FL 33146-0630 (United States); Zhao, Dongye [Department of Civil and Environmental Engineering, 238 Harbert Engineering Center, Auburn University, Auburn, AL 36849 (United States)

    2017-01-15

    Highlights: • Influence of contaminants on the mobility of metal oxide nanoparticles (MNPs). • Synergistic effects of MNPs in the presence of contaminants. • Effect of environmental factors on the transformed MNPs. • Research direction on the toxicity modeling assessment of heterogeneous systems. - Abstract: Metal oxide nanoparticles (MNPs) have been used for many purposes including water treatment, health, cosmetics, electronics, food packaging, and even food products. As their applications continue to expand, concerns have been mounting about the environmental fate and potential health risks of the nanoparticles in the environment. Based on the latest information, this review provides an overview of the factors that affect the fate, transformation and toxicity of MNPs. Emphasis is placed on the effects of various aquatic contaminants under various environmental conditions on the transformation of metal oxides and their transport kinetics – both in homogeneous and heterogeneous systems – and the effects of contaminants on the toxicity of MNPs. The presence of existing contaminants decreases bioavailability through hetero-aggregation, sorption, and/or complexation upon an interaction with MNPs. Contaminants also influence the fate and transport of MNPs and exhibit their synergistic toxic effects that contribute to the extent of the toxicity. This review will help regulators, engineers, and scientists in this field to understand the latest development on MNPs, their interactions with aquatic contaminants as well as the environmental dynamics of their fate and transformation. The knowledge gap and future research needs are also identified, and the challenges in assessing the environmental fate and transport of nanoparticles in heterogeneous systems are discussed.

  13. Experience on the removal of impurities from liquid metal systems by cold-trapping

    Energy Technology Data Exchange (ETDEWEB)

    Bray, J. A.

    1963-10-15

    Experience in impurity removal by cold-trapping, which was obtained on DFR and its associated liquid metal rigs, is reviewed. The development of the present DFR cold-trapping system is outlined, and the operation of the additional pumped loops, which were required in order to control the reactor impurity levels, are described. Operation of the liquid metal rigs ancillary to the reactor project is discussed with particular reference to the control of impurity levels. (auth)

  14. Metal Matrix Composite Solar Cell Metallization

    Directory of Open Access Journals (Sweden)

    Wilt David M.

    2017-01-01

    Full Text Available Advanced solar cells are moving to ever thinner formats in order to save mass and in some cases improve performance. As cells are thinned, the possibility that they may fracture or cleave due to mechanical stresses is increased. Fractures of the cell can degrade the overall device performance if the fracture propagates through the contact metallization, which frequently occurs. To address this problem, a novel semiconductor metallization system based on multi-walled carbon nanotube (CNT reinforcement, termed metal matrix composite (MMC metallization is under investigation. Electro-mechanical characterization of MMC films demonstrate their ability to provide electrical conductivity over >40 micron wide cracks in the underlying semiconductor, with the carbon nanotubes bridging the gap. In addition, these materials show a “self-healing” behaviour, electrically reconnecting at ~30 microns when strained past failure. Triple junction (TJ space cells with MMC metallization demonstrated no loss in Jsc after intentional fracture, whereas TJ cells with conventional metallization suffer up to 50% Jsc loss.

  15. On the systems of automatic non-destructive control of NPP metallic structures

    International Nuclear Information System (INIS)

    Grebennik, V.S.; Lantukh, V.M.

    1980-01-01

    The main stages of developing automatic systems of non- destructive control (NC) of NPP metallic structures are pointed out. The main requirements for automatic NC systems are formulated. Recommendations on the use of the developed experimental automatic facilities for control of certain NPP components are given. It is noted that the present facilities may be used in the future in development of modular sets of non-destructive control systems [ru

  16. METALert - an emergency response system for China for heavy metals in the environment

    Science.gov (United States)

    Joris, Ingeborg; Seuntjens, Piet; Dams, Jef; Desmet, Nele; Van Looy, Stijn; Raymaekers, Jens; Decorte, Lieve; Raben, Ingrid; Thijssen, Chris; Zhang, Hongzhen; Dong, Jingqi; Zhang, Qianwen

    2016-04-01

    The rapid industrialisation and economic growth of China has resulted in a mirrored increase of environmental issues and threats, which make the updating of the current environmental emergency response protocols very important. Heavy metal pollution accidents with high environmental risks are happening more frequently than ever in recent years. Despite efforts made by the authorites in respect to the formulation of sound policy, efficient technical methods and regulations for dealing with appropriate responses to emergency environmental incidents related to heavy metal pollution are still lacking. METALert is a generic Emergency Response System (ERS) for accidental pollution incidents caused by key heavy metal related industries in China and developed to support China in achieving its environmental targets. The METALert tool is based on environmental models for forecasting, simulation and visualisation of dispersion of heavy metal pollution in water, air and soil. The tool contains a generic database with scenarios for accidental release of metals in typical accidents related to the five key heavy metal industries in China. The tool can calculate the impact of an accident in water, air and soil and is evaluated and demonstrated for a river basin in the Chenzhou area, an important heavy metal mining area in China. The setup of the tool, the background models and the application in Chenzhou will be presented.

  17. PREDOMINANTLY LOW METALLICITIES MEASURED IN A STRATIFIED SAMPLE OF LYMAN LIMIT SYSTEMS AT Z  = 3.7

    Energy Technology Data Exchange (ETDEWEB)

    Glidden, Ana; Cooper, Thomas J.; Simcoe, Robert A. [Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139 (United States); Cooksey, Kathy L. [Department of Physics and Astronomy, University of Hawai‘i at Hilo, 200 West Kāwili Street, Hilo, HI 96720 (United States); O’Meara, John M., E-mail: aglidden@mit.edu, E-mail: tjcooper@mit.edu, E-mail: simcoe@space.mit.edu, E-mail: kcooksey@hawaii.edu, E-mail: jomeara@smcvt.edu [Department of Physics, Saint Michael’s College, One Winooski Park, Colchester, VT 05439 (United States)

    2016-12-20

    We measured metallicities for 33 z = 3.4–4.2 absorption line systems drawn from a sample of H i-selected-Lyman limit systems (LLSs) identified in Sloan Digital Sky Survey (SDSS) quasar spectra and stratified based on metal line features. We obtained higher-resolution spectra with the Keck Echellette Spectrograph and Imager, selecting targets according to our stratification scheme in an effort to fully sample the LLS population metallicity distribution. We established a plausible range of H i column densities and measured column densities (or limits) for ions of carbon, silicon, and aluminum, finding ionization-corrected metallicities or upper limits. Interestingly, our ionization models were better constrained with enhanced α -to-aluminum abundances, with a median abundance ratio of [ α /Al] = 0.3. Measured metallicities were generally low, ranging from [M/H] = −3 to −1.68, with even lower metallicities likely for some systems with upper limits. Using survival statistics to incorporate limits, we constructed the cumulative distribution function (CDF) for LLS metallicities. Recent models of galaxy evolution propose that galaxies replenish their gas from the low-metallicity intergalactic medium (IGM) via high-density H i “flows” and eject enriched interstellar gas via outflows. Thus, there has been some expectation that LLSs at the peak of cosmic star formation ( z  ≈ 3) might have a bimodal metallicity distribution. We modeled our CDF as a mix of two Gaussian distributions, one reflecting the metallicity of the IGM and the other representative of the interstellar medium of star-forming galaxies. This bimodal distribution yielded a poor fit. A single Gaussian distribution better represented the sample with a low mean metallicity of [M/H] ≈ −2.5.

  18. Gases and carbon in metals

    International Nuclear Information System (INIS)

    Jehn, H.; Fromm, E.; Hoerz, G.

    1978-01-01

    This issue is part of a series of data on 'gases and carbon in metals'. The present survey includes results from papers dealing with gases and carbon in actinides and recommends critically selected data for each element. Firstly data od binary systems are presented, starting with hydrogen and followed by carbon, nitrogen, oxygen, and rare gases. Within one metal-metalloid system the data are listed under topics such as solubility limit, dissociation pressure of compunds, vapour pressure of volatile oxides, thermodynamic data, diffusion, transport parameters (effective valence, heat of transport), permeation of gases through metals, gas adsorption and gas desorption kinetics, compound formation, precipitation kinetics, and property changes. Following the data on binary systems, the data of ternary systems are presented, beginning with systems which contain one metal and two gases or one gas and carbon and continuing with systems with two metals and one gas or carbon. Within a ternary system the topics are arranged in the same way as in binary systems. (HB) [de

  19. Metal-based nanoparticle interactions with the nervous system: The challenge of brain entry and the risk of retention in the organism

    Science.gov (United States)

    This review of metal and metal-oxide based nanoparticles focuses on factors that influence their distribution into the nervous system, evidence that they enter brain parenchyma, and nervous system responses. Emphasis is placed on gold as a model metal-based nanoparticle and for r...

  20. Implication of heavy metals distribution for a municipal solid waste management system - a case study in Shanghai

    International Nuclear Information System (INIS)

    Zhang Hua; He Pinjing; Shao Liming

    2008-01-01

    Heavy metal contamination in municipal solid waste (MSW) is of increasing concern. The occurrence and distribution of heavy metals in MSW and their implications for the integrated MSW management system in mega-cities have been investigated by means of material flow analysis based on a case study of Shanghai in China. A good statistical basis was provided through a one-year monitoring program on the mass and metals composition of the waste from three MSW treatment facilities. The results showed that the main heavy metals in the MSW were Zn, Cr, Cu, and Pb (on average > 100 mg kg -1 ), followed by Ni, Cd, and Hg. The MSW contained higher levels of Cu and Ni in metals, Cr and Pb in plastics, and Pb and Zn in the inorganic fractions. Regardless of the sources, the statistically similar heavy metal contents in the organic fractions indicated that effective blending and diffusion of heavy metals had taken place throughout the MSW collection, transfer, transportation, and storage, leading to cross-contamination of the waste fractions. PU (composed of putrescible waste and miscellaneous indistinguishable particles) contributed the majority of the heavy metals to the MSW, followed by plastics, as a result of the predominance in the overall composition of PU and plastics rather than from differences in their heavy metal contents. Therefore, manual or mechanical separation of some significantly heavy metal-rich fractions alone is not sufficient to reduce the heavy metal contents in the MSW. Source separation of organic waste and the diversion of tailored inorganic waste such as hazardous components, construction and demolition waste, etc., are proposed to control the heavy metal contamination in MSW. For the mixed MSW management system, physicochemical fractionation to exclude particles containing high levels of heavy metals can be conducted

  1. Implication of heavy metals distribution for a municipal solid waste management system - a case study in Shanghai

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Hua [State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); He Pinjing [State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China)], E-mail: solidwaste@mail.tongji.edu.cn; Shao Liming [State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China)

    2008-09-01

    Heavy metal contamination in municipal solid waste (MSW) is of increasing concern. The occurrence and distribution of heavy metals in MSW and their implications for the integrated MSW management system in mega-cities have been investigated by means of material flow analysis based on a case study of Shanghai in China. A good statistical basis was provided through a one-year monitoring program on the mass and metals composition of the waste from three MSW treatment facilities. The results showed that the main heavy metals in the MSW were Zn, Cr, Cu, and Pb (on average > 100 mg kg{sup -1}), followed by Ni, Cd, and Hg. The MSW contained higher levels of Cu and Ni in metals, Cr and Pb in plastics, and Pb and Zn in the inorganic fractions. Regardless of the sources, the statistically similar heavy metal contents in the organic fractions indicated that effective blending and diffusion of heavy metals had taken place throughout the MSW collection, transfer, transportation, and storage, leading to cross-contamination of the waste fractions. PU (composed of putrescible waste and miscellaneous indistinguishable particles) contributed the majority of the heavy metals to the MSW, followed by plastics, as a result of the predominance in the overall composition of PU and plastics rather than from differences in their heavy metal contents. Therefore, manual or mechanical separation of some significantly heavy metal-rich fractions alone is not sufficient to reduce the heavy metal contents in the MSW. Source separation of organic waste and the diversion of tailored inorganic waste such as hazardous components, construction and demolition waste, etc., are proposed to control the heavy metal contamination in MSW. For the mixed MSW management system, physicochemical fractionation to exclude particles containing high levels of heavy metals can be conducted.

  2. Electrostatic analysis of n-doped SrTiO3 metal-insulator-semiconductor systems

    International Nuclear Information System (INIS)

    Kamerbeek, A. M.; Banerjee, T.; Hueting, R. J. E.

    2015-01-01

    Electron doped SrTiO 3 , a complex-oxide semiconductor, possesses novel electronic properties due to its strong temperature and electric-field dependent permittivity. Due to the high permittivity, metal/n-SrTiO 3 systems show reasonably strong rectification even when SrTiO 3 is degenerately doped. Our experiments show that the insertion of a sub nanometer layer of AlO x in between the metal and n-SrTiO 3 interface leads to a dramatic reduction of the Schottky barrier height (from around 0.90 V to 0.25 V). This reduces the interface resistivity by 4 orders of magnitude. The derived electrostatic analysis of the metal-insulator-semiconductor (n-SrTiO 3 ) system is consistent with this trend. When compared with a Si based MIS system, the change is much larger and mainly governed by the high permittivity of SrTiO 3 . The non-linear permittivity of n-SrTiO 3 leads to unconventional properties such as a temperature dependent surface potential non-existent for semiconductors with linear permittivity such as Si. This allows tuning of the interfacial band alignment, and consequently the Schottky barrier height, in a much more drastic way than in conventional semiconductors

  3. MetalS(3), a database-mining tool for the identification of structurally similar metal sites.

    Science.gov (United States)

    Valasatava, Yana; Rosato, Antonio; Cavallaro, Gabriele; Andreini, Claudia

    2014-08-01

    We have developed a database search tool to identify metal sites having structural similarity to a query metal site structure within the MetalPDB database of minimal functional sites (MFSs) contained in metal-binding biological macromolecules. MFSs describe the local environment around the metal(s) independently of the larger context of the macromolecular structure. Such a local environment has a determinant role in tuning the chemical reactivity of the metal, ultimately contributing to the functional properties of the whole system. The database search tool, which we called MetalS(3) (Metal Sites Similarity Search), can be accessed through a Web interface at http://metalweb.cerm.unifi.it/tools/metals3/ . MetalS(3) uses a suitably adapted version of an algorithm that we previously developed to systematically compare the structure of the query metal site with each MFS in MetalPDB. For each MFS, the best superposition is kept. All these superpositions are then ranked according to the MetalS(3) scoring function and are presented to the user in tabular form. The user can interact with the output Web page to visualize the structural alignment or the sequence alignment derived from it. Options to filter the results are available. Test calculations show that the MetalS(3) output correlates well with expectations from protein homology considerations. Furthermore, we describe some usage scenarios that highlight the usefulness of MetalS(3) to obtain mechanistic and functional hints regardless of homology.

  4. Colonization by Cladosporium spp. of painted metal surfaces associated with heating and air conditioning systems

    Science.gov (United States)

    Ahearn, D. G.; Simmons, R. B.; Switzer, K. F.; Ajello, L.; Pierson, D. L.

    1991-01-01

    Cladosporium cladosporioides and C. hebarum colonized painted metal surfaces of covering panels and register vents of heating, air conditioning and ventilation systems. Hyphae penetrated the paint film and developed characteristic conidiophores and conidia. The colonies were tightly appressed to the metal surface and conidia were not readily detectable via standard air sampling procedures.

  5. Stormwater Effects on Heavy Metal Sequestration in a Bioretention System in Culver City, California

    Science.gov (United States)

    Yousavich, D. J.; Ellis, A. S.; Dorsey, J.; Johnston, K.

    2017-12-01

    Rain Gardens, also referred to as bioretention or biofilters, are often used to capture or filter urban runoff before it drains into surface or groundwater systems. The Culver City Rain Garden (CCRG) is one such system that is designed to capture and filter runoff from approximately 11 acres of mixed-use commercial and industrial land before it enters Ballona Creek. The EPA has designated Ballona Creek as an impaired waterway and established Total Maximum Daily Loads for heavy metals. Previous research has utilized sequential extractions to establish trends in heavy metal sequestration for Cu, Pb, and Zn in bioretention media. The aim of this project is to evaluate if there is a difference in heavy metal sequestration between dry and wetted bioretention media. To characterize the stormwater at the site, influent and surface water were collected and analyzed for sulfate and heavy metals 3 times during the 2016-2017 storm season. Two soil cores from the CCRG were acquired in the summer of 2017 to analyze soil metal sequestration trends. They will be subjected to different wetting conditions, sectioned into discrete depths, and digested with an established sequential extraction technique. Surface water in the CCRG shows average Dissolved Oxygen during wet conditions of 2.92 mg/L and average pH of 6.1 indicating reducing conditions near the surface and the possible protonation of adsorption sites during wet weather conditions. Influent metal data indicate average dissolved iron levels near 1 ppm and influent Cu, Pb, and Zn levels near 0.05, 0.01, and 0.5 ppm respectively. This coupled with average surface water sulfate levels near 3 ppm indicates the potential for iron oxide and sulfide mineral formation depending on redox conditions. The sequential extraction results will elucidate whether heavy metals are adsorbed or are being sequestered in mineral formation. These results will allow for the inclusion of heavy metal sequestration trends in the design of further

  6. Performance analysis of a mixed nitride fuel system for an advanced liquid metal reactor

    International Nuclear Information System (INIS)

    Lyon, W.F.; Baker, R.B.; Leggett, R.D.

    1991-01-01

    In this paper, the conceptual development and analysis of a proposed mixed nitride driver and blanket fuel system for a prototypic advanced liquid metal reactor design is performed. As a first step, an intensive literature survey is completed on the development and testing of nitride fuel systems. Based on the results of this survey, prototypic mixed nitride fuel and blanket pins is designed and analyzed using the SIEX computer code. The analysis predicts that the nitride fuel consistently operated at peak temperatures and cladding strain levels that compared quite favorably with competing fuel designs. These results, along with data available in the literature on nitride fuel performance, indicate that a nitride fuel system should offer enhanced capabilities for advanced liquid metal reactors

  7. Performance analysis of a mixed nitride fuel system for an advanced liquid metal reactor

    International Nuclear Information System (INIS)

    Lyon, W.F.; Baker, R.B.; Leggett, R.D.

    1990-11-01

    The conceptual development and analysis of a proposed mixed nitride driver and blanket fuel system for a prototypic advanced liquid metal reactor design has been performed. As a first step, an intensive literature survey was completed on the development and testing of nitride fuel systems. Based on the results of this survey, prototypic mixed nitride fuel and blanket pins were designed and analyzed using the SIEX computer code. The analysis predicted that the nitride fuel consistently operated at peak temperatures and cladding strain levels that compared quite favorably with competing fuel designs. These results, along with data available in the literature on nitride fuel performance, indicate that a nitride fuel system should offer enhanced capabilities for advanced liquid metal reactors. 13 refs., 10 figs., 2 tabs

  8. by Phanerochaete chrysosporium from a binary metal system

    African Journals Online (AJOL)

    drinie

    2001-01-01

    Jan 1, 2001 ... metal concentrations (Ci) increased, independent of initial pH (pHi) and generally the metal with ... The results also show that some portion of the metal ions sorbed by P. ... mechanisms, mainly ion exchange, chelation, adsorption, and ..... YU Q and KAEWSARN P (1999) Binary adsorption of copper(II) and.

  9. HOT CELL SYSTEM FOR DETERMINING FISSION GAS RETENTION IN METALLIC FUELS

    Energy Technology Data Exchange (ETDEWEB)

    Sell, D. A.; Baily, C. E.; Malewitz, T. J.; Medvedev, P. G.; Porter, D. L.; Hilton, B. A.

    2016-09-01

    A system has been developed to perform measurements on irradiated, sodium bonded-metallic fuel elements to determine the amount of fission gas retained in the fuel material after release of the gas to the element plenum. During irradiation of metallic fuel elements, most of the fission gas developed is released from the fuel and captured in the gas plenums of the fuel elements. A significant amount of fission gas, however, remains captured in closed porosities which develop in the fuel during irradiation. Additionally, some gas is trapped in open porosity but sealed off from the plenum by frozen bond sodium after the element has cooled in the hot cell. The Retained fission Gas (RFG) system has been designed, tested and implemented to capture and measure the quantity of retained fission gas in characterized cut pieces of sodium bonded metallic fuel. Fuel pieces are loaded into the apparatus along with a prescribed amount of iron powder, which is used to create a relatively low melting, eutectic composition as the iron diffuses into the fuel. The apparatus is sealed, evacuated, and then heated to temperatures in excess of the eutectic melting point. Retained fission gas release is monitored by pressure transducers during the heating phase, thus monitoring for release of fission gas as first the bond sodium melts and then the fuel. A separate hot cell system is used to sample the gas in the apparatus and also characterize the volume of the apparatus thus permitting the calculation of the total fission gas release from the fuel element samples along with analysis of the gas composition.

  10. Off-Line Testing of Tribo-Systems for Sheet Metal Forming Production

    DEFF Research Database (Denmark)

    Bay, Niels; Ceron, Ermanno

    2014-01-01

    Off-line testing of new tribo-systems for sheet metal forming production is an important issue, when new, environmentally benign lubricants are to be introduced. To obtain useful results it is, however, vital to ensure similar conditions as in the production process regarding the main tribo...... leading to very high tool/workpiece interface pressure and temperature in the second re-draw. Under such conditions only the best lubricant systems work satisfactory, and the paper shows how the performance of different tribo-systems in production may be predicted by off-line testing combined...

  11. Treatment of heavy metals by iron oxide coated and natural gravel media in Sustainable urban Drainage Systems.

    Science.gov (United States)

    Norris, M J; Pulford, I D; Haynes, H; Dorea, C C; Phoenix, V R

    2013-01-01

    Sustainable urban Drainage Systems (SuDS) filter drains are simple, low-cost systems utilized as a first defence to treat road runoff by employing biogeochemical processes to reduce pollutants. However, the mechanisms involved in pollution attenuation are poorly understood. This work aims to develop a better understanding of these mechanisms to facilitate improved SuDS design. Since heavy metals are a large fraction of pollution in road runoff, this study aimed to enhance heavy metal removal of filter drain gravel with an iron oxide mineral amendment to increase surface area for heavy metal scavenging. Experiments showed that amendment-coated and uncoated (control) gravel removed similar quantities of heavy metals. Moreover, when normalized to surface area, iron oxide coated gravels (IOCGs) showed poorer metal removal capacities than uncoated gravel. Inspection of the uncoated microgabbro gravel indicated that clay particulates on the surface (a natural product of weathering of this material) augmented heavy metal removal, generating metal sequestration capacities that were competitive compared with IOCGs. Furthermore, when the weathered surface was scrubbed and removed, metal removal capacities were reduced by 20%. When compared with other lithologies, adsorption of heavy metals by microgabbro was 10-70% higher, indicating that both the lithology of the gravel, and the presence of a weathered surface, considerably influence its ability to immobilize heavy metals. These results contradict previous assumptions which suggest that gravel lithology is not a significant factor in SuDS design. Based upon these results, weathered microgabbro is suggested to be an ideal lithology for use in SuDS.

  12. Modelling metal-humic substances-surface systems: reasons for success, failure and possible routes for peace of mind

    International Nuclear Information System (INIS)

    Reiller, P.E.

    2012-01-01

    Iron oxides and oxy-hydroxides are commonly of considerable importance in the sorption of ions onto rocks, soils and sediments. They can be the controlling sorptive phases even if they are present in relatively small quantities. In common with other oxides and clay minerals, the sorption pH-edge of metals is directly linked to their hydrolysis: the higher the residual charge on the metal ion, the lower the pH-edge. Modelling of this process has been successfully carried out using different microscopic or macroscopic definitions of the interface (e.g. surface complexation or ion exchange models that may or may not include mineralogical descriptions). The influence of organic material on the sorption of many metals is of significant. This organic material includes simple organic molecules and more complex exo-polymeric substances (e.g. humic substances) produced by the decay of natural organic matter. Sorption of this organic material to mineral surfaces has been the subject of a large body of work. The various types of organic substances do not share the same affinities for mineral surfaces in general, and for iron oxides and oxy-hydroxides in particular. In those cases in which successful models of the component binary systems (i.e. metal-surface, metal-organic, organic-surface) have been developed, the formation of mixed surface complexes, the evolution of the surface itself, the addition order in laboratory systems, and the evolution of natural organic matter fractions during sorption, have often precluded a satisfactory description of metal-surface-organic ternary systems over a sufficiently wide range of parameter values (i.e. pH, ionic strength, concentration of humic substances). This manuscript describes the reasons for some successes and failures in the modelling of the ternary systems. Promising recent advances and possible methods of providing more complete descriptions of these intricate systems are also discussed. (author)

  13. Plasma coatings of nitrogen polymers on metal prostheses of the circulatory system

    International Nuclear Information System (INIS)

    Gomez J, L. M.

    2016-01-01

    This work has a study about the synthesis of poly aniline, poly allylamine and poly pyrrole doped with iodine onto metallic surfaces similar to stents for the circulatory system. Ar, water and hydrogen peroxide plasmas were used for eroding, conditioning and synthesizing polymers that potentially reduce some rejection reactions when stents are implanted in the human body. Stents are small metallic meshes that applied inside collapsed arteries or veins enlarge the diameter and restore the blood flow, however the metallic surfaces usually cause rejection reactions that obstruct the veins again. To give solutions to this problem, in this work is studied the synthesis of biocompatible polymer coatings on the stents that resist the blood flow forming a biocompatible interface between metal and blood. The metallic substrates were eroded and chemically prepared with Ar, H_2O and/or H_2O_2 glow discharges on which the polymers were synthesized by plasma. The coatings were morphologically characterized by optical, scanning electron and atomic force microscopy, the chemical structure was studied by infrared and photoelectron X-ray spectroscopy. The hydrophilicity was studied measuring the advance static contact angle and the adhesion was evaluated indirectly with scanning electron microscopy after two months submerged in buffered phosphate solutions. The results indicate that the polymers grew following the superficial morphology; that the conditioning with Ar ions erode the substrates and that the conditioning with H_2O or H_2O_2 erodes and activates the surface generating oxygen bridges which help in the polymer-metal adhesion. The chemical structure of the polymeric coatings contain crosslinked structures that correspond to links between monomers with the participation of all atoms, states that suggest monomer fragmentation and oxidation and states that indicate oxygen bridges in the polymers. The coatings had contact angles close to 90 degrees where is located the line

  14. Large resistivity modulation in mixed-phase metallic systems.

    Science.gov (United States)

    Lee, Yeonbae; Liu, Z Q; Heron, J T; Clarkson, J D; Hong, J; Ko, C; Biegalski, M D; Aschauer, U; Hsu, S L; Nowakowski, M E; Wu, J; Christen, H M; Salahuddin, S; Bokor, J B; Spaldin, N A; Schlom, D G; Ramesh, R

    2015-01-07

    In numerous systems, giant physical responses have been discovered when two phases coexist; for example, near a phase transition. An intermetallic FeRh system undergoes a first-order antiferromagnetic to ferromagnetic transition above room temperature and shows two-phase coexistence near the transition. Here we have investigated the effect of an electric field to FeRh/PMN-PT heterostructures and report 8% change in the electrical resistivity of FeRh films. Such a 'giant' electroresistance (GER) response is striking in metallic systems, in which external electric fields are screened, and thus only weakly influence the carrier concentrations and mobilities. We show that our FeRh films comprise coexisting ferromagnetic and antiferromagnetic phases with different resistivities and the origin of the GER effect is the strain-mediated change in their relative proportions. The observed behaviour is reminiscent of colossal magnetoresistance in perovskite manganites and illustrates the role of mixed-phase coexistence in achieving large changes in physical properties with low-energy external perturbation.

  15. An expert system for process planning of sheet metal parts produced

    Indian Academy of Sciences (India)

    Process planning of sheet metal part is an important activity in the design of compound die. Traditional methods of carrying out this task are manual, tedious, time-consuming, error-prone and experiencebased. This paper describes the research work involved in the development of an expert system for process planning of ...

  16. Vapor trap for liquid metal

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, T

    1968-05-22

    In a pipe system which transfers liquid metal, inert gas (cover gas) is packed above the surface of the liquid metal to prevent oxidization of the liquid. If the metal vapor is contained in such cover gas, the circulating system of the cover gas is blocked due to condensation of liquid metal inside the system. The present invention relates to an improvement in vapor trap to remove the metal vapor from the cover gas. The trap consists of a cylindrical outer body, an inlet nozzle which is deeply inserted inside the outer body and has a number of holes to inject the cove gas into the body, metal mesh or steel wool which covers the exterior of the nozzle and on which the condensation of the metal gas takes place, and a heater wire hich is wound around the nozzle to prevent condensation of the metal vapor at the inner peripheral side of the mesh.

  17. A systems approach to the management of a contaminated metal recycle project

    International Nuclear Information System (INIS)

    Pincock, L.; Wahnachaffe, S.

    1994-01-01

    Westinghouse Idaho Nuclear Company (WINCO) is working with private industry to recycle contaminated metal from the dismantling and decommissioning of Department of Energy sites and commercial reactors. The recycled metal could be used in many applications such as fabrication of canisters and waste boxes for the storage of spent nuclear fuel and radioactive waste. Management of technical projects similar to this is difficult because these projects consist of a myriad of complex and interrelated issues ranging from technical feasibility to stakeholder acceptance. Systems Analysis provides a way to deal with many complex issues and supports effective decision making

  18. Manipulating Light with Transition Metal Clusters, Organic Dyes, and Metal Organic Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Ogut, Serdar [Univ. of Illinois, Chicago, IL (United States)

    2017-09-11

    The primary goals of our research program is to develop and apply state-of-the-art first-principles methods to predict electronic and optical properties of three systems of significant scientific and technological interest: transition metal clusters, organic dyes, and metal-organic frameworks. These systems offer great opportunities to manipulate light for a wide ranging list of energy-related scientific problems and applications. During this grant period, we focused our investigations on the development, implementation, and benchmarking of many-body Green’s function methods (GW approximation and the Bethe-Salpeter equation) to examine excited-state properties of transition metal/transition-metal-oxide clusters and organic molecules that comprise the building blocks of dyes and metal-organic frameworks.

  19. Systems and Methods for Fabricating Structures Including Metallic Glass-Based Materials Using Low Pressure Casting

    Science.gov (United States)

    Hofmann, Douglas C. (Inventor); Kennett, Andrew (Inventor)

    2018-01-01

    Systems and methods to fabricate objects including metallic glass-based materials using low-pressure casting techniques are described. In one embodiment, a method of fabricating an object that includes a metallic glass-based material includes: introducing molten alloy into a mold cavity defined by a mold using a low enough pressure such that the molten alloy does not conform to features of the mold cavity that are smaller than 100 microns; and cooling the molten alloy such that it solidifies, the solid including a metallic glass-based material.

  20. The Responses of Antioxidant System against the Heavy Metal-Induced Stress in Tomato

    Directory of Open Access Journals (Sweden)

    Dursun KISA

    2017-12-01

    Full Text Available Plants maintain their life cycles under the various environmental conditions such as oxidative stress induced by heavy metals. Accumulation of metal ions in plants causes the formation of free radicals and stimulates the antioxidative defense systems. In this study, the activities of APX, POD, and SOD are investigated in the leaves and roots of tomato cultivated under the heavy metal-induced stress. The activities of APX, POD, and SOD exhibited remarkable induction with the treatment of Cd, Cu and Pb (10, 20 and 50 ppm in the leaves of tomato compared to control plants except for 50 ppm Pb. In roots, APX activity changed depending on the heavy metal types and concentrations, while Cd clearly increased it with stress conditions, but Cu decreased in tomato compared to control. The activity of POD clearly exhibited that the all doses of heavy metals reduced the enzyme activity in roots polluted with heavy metals. The treatment of Cd (10, 20 and 50 ppm significantly increased the activity of SOD, however, Cu showed the opposite effect which significantly decreased with increasing doses in roots compared to uncontaminated plants. Also, roots from plants grown on the high concentration of Pb (20 and 50 ppm induced the activity of SOD. Briefly, it is clear responses which Cd significantly raised the activities of APX and SOD in leaves and roots of tomato. The decreases caused by these metals in the activity of POD and Cu in the activities of APX and SOD in roots of tomato can be clarified by the result of heavy metal-induced the over production of free radical.

  1. Liquid metal purification device

    International Nuclear Information System (INIS)

    Sakai, Takao; Shimoyashiki, Shigehiro.

    1992-01-01

    The device of the present invention concerns a liquid metal purification device for removing and purifying impuries in liquid metal sodium used as coolants of an FBR type reactor. A vessel having a group of pipes made of hydrogen permeable metal at the inside thereof is disposed to the inlet pipeline of a cold trap. The group of hydrogen permeable metal pipes is connected to an exhaust pipe and a vacuum pump, so that the inside of the pipes is exhausted. Liquid metal sodium branched from the main pipeline of a coolant system passes through the outer side of the group of the hydrogen permeable metal pipes. In this cae, hydrogen contained as impurities in the liquid metal sodium diffuses and permeates the hydrogen permeation metal pipes and enters into the pipe group and is discharged out of the system by the vacuum pump. This can mitigate the hydrogen removing burden of the cold trap, to extend the device life time. (I.N.)

  2. Potential of multi-purpose liquid metallic fuelled fast reactor (MPFR) as a hydrogen production system

    International Nuclear Information System (INIS)

    Endo, H.; Ninokata, H.; Netchaev, A.; Sawada, T.

    2001-01-01

    Nuclear energy is the only effective alternative energy source to fossil fuels in the next century. Therefore future nuclear power plants should satisfy the following three requirements: i) multiple energy conversion capability with high temperature not only for electricity generation but also for hydrogen production, ii) extended siting capability so as to eliminate on-site refuelling, and iii) passive safety features. An aim of this paper is to describe the basic concept of the multi-purpose liquid metallic fuelled fast reactor system (MPFR). The MPFR introduces the U-Pu-X (X: Mn, Fe, Co) liquid metallic alloy with Ta and Ta/TaC structural materials, and satisfies all of the conditions listed above based on the following characteristics of the liquid metallic fuel: high temperature operation between 650 deg C (sodium-cooled system) and 1 200 deg C (lead-cooled system), a core lifetime of 15-30 years without radiation damage of fuel materials, and enhanced passive safety by the thermal expansion of liquid fuel and the avoidance of re-criticality due to local core fuel dispersion at fuel failure events. (authors)

  3. Molten salt oxidation of ion-exchange resins doped with toxic metals and radioactive metal surrogates

    International Nuclear Information System (INIS)

    Yang, Hee-Chul; Cho, Yong-Jun; Yoo, Jae-Hyung; Kim, Joon-Hyung; Eun, Hee-Chul

    2005-01-01

    Ion-exchange resins doped with toxic metals and radioactive metal surrogates were test-burned in a bench-scale molten salt oxidation (MSO) reactor system. The purposes of this study are to confirm the destruction performance of the two-stage MSO reactor system for the organic ion-exchange resin and to obtain an understanding of the behavior of the fixed toxic metals and the sulfur in the cationic exchange resins. The destruction of the organics is very efficient in the primary reactor. The primarily destroyed products such as carbon monoxide are completely oxidized in the secondary MSO reactor. The overall collection of the sulfur and metals in the two-stage MSO reactor system appeared to be very efficient. Over 99.5% of all the fixed toxic metals (lead and cadmium) and radioactive metal surrogates (cesium, cobalt, strontium) remained in the MSO reactor bottom. Thermodynamic equilibrium calculations and the XRD patterns of the spent salt samples revealed that the collected metals existed in the form of each of their carbonates or oxides, which are non-volatile species at the MSO system operating conditions. (author)

  4. The Distribution of Heavy Metal Pollutants in Suez Bay Using Geographic Information System (GIS)

    International Nuclear Information System (INIS)

    Hassan, H.B.; Mohamed, W.M.

    2017-01-01

    Suez city represents the southern entrance of the Suez Canal. As a result of the rapid development of industrialization and anthropogenic activities of Suez city may be entered containments such as heavy metals through Suez bay boundaries. The geographical information system (Arc GIS 9.1) is used to study the spatial distribution of heavy metals concentrations (Cd, Mn, Fe, Ni, Pb, Cu and Zn) of water samples which were collected in four different sampling sites (I, II, III and IV) from Suez bay. In this study, tabular data representation of the spatial distribution was developed using the inverse distance weighted (IDW) interpolation method. The GIS technique was applied to transfer the information into a final map illustrating the spatial distribution of heavy metals within the studied area. GIS models showed the high concentrations of heavy metals in some sites in the Suez city affecting by their activities. An overall distribution map of heavy metals is observed from GIS special analysis. Site (IV) in Suez City demonstrated the highest polluted are a in the overall distribution map

  5. Study of metal removal by square Wetland System with Eleocharis SP. using SR-XRF

    International Nuclear Information System (INIS)

    Avelino Neto, Sebastiao; Moreira, Silvana

    2007-01-01

    The pollution of the water resources for metals, results of different economic activities. The objective of the present study was to use the SR-TXRF technique to evaluate the performance of Wetland system cultivated with Eleocharis sp. installed at FEAGRI-UNICAMP, in the metal removal. The metals analyzed were Cr, Mn, Fe, Zn and Pb. Samples of the wastewater in the exit, Eleocharis sp. leaf and medium boulder were collected during 20 weeks consecutively. The system was operated with different outflows and hydraulic detention times (HDT) as: 600 L.day -1 (HDT 2 days), 400 L.day-1 (HDT 3 days), 300 L.day -1 (HDT 4 days) and 200 L.day -1 (HDT 6 days). The main source of metal removal was medium boulder with efficiency varying 30.1% for Cr and 98.9% for Pb, independent of the hydraulic detention time (HDT) used. The efficiency of the wetland in the Cr removal varied between 39.6 and 98.7%, and for Mn was higher than 81.6%. For Fe the performance was higher than 70.6% and for Cu the efficiency varied between 88.4 and 99.7 %, while for Pb the variation was 67.5 to 98.4 %. The wetland system with Eleocharis sp were in agreement with CONAMA legislation concern to Fe, Cu and Zn removal and for HDT of 2, 3, 4 and 6 days (HDT), moreover for Mn was necessary 4 and 6 days (HDT) and for Cr and Pb 6 days (HDT). (author)

  6. Study of metal removal by square Wetland System with Eleocharis SP. using SR-XRF

    Energy Technology Data Exchange (ETDEWEB)

    Avelino Neto, Sebastiao; Moreira, Silvana [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo]. E-mails: savneto@bol.com.br; silvana@fec.unicamp.br

    2007-07-01

    The pollution of the water resources for metals, results of different economic activities. The objective of the present study was to use the SR-TXRF technique to evaluate the performance of Wetland system cultivated with Eleocharis sp. installed at FEAGRI-UNICAMP, in the metal removal. The metals analyzed were Cr, Mn, Fe, Zn and Pb. Samples of the wastewater in the exit, Eleocharis sp. leaf and medium boulder were collected during 20 weeks consecutively. The system was operated with different outflows and hydraulic detention times (HDT) as: 600 L.day{sup -1} (HDT 2 days), 400 L.day-1 (HDT 3 days), 300 L.day{sup -1} (HDT 4 days) and 200 L.day{sup -1} (HDT 6 days). The main source of metal removal was medium boulder with efficiency varying 30.1% for Cr and 98.9% for Pb, independent of the hydraulic detention time (HDT) used. The efficiency of the wetland in the Cr removal varied between 39.6 and 98.7%, and for Mn was higher than 81.6%. For Fe the performance was higher than 70.6% and for Cu the efficiency varied between 88.4 and 99.7 %, while for Pb the variation was 67.5 to 98.4 %. The wetland system with Eleocharis sp were in agreement with CONAMA legislation concern to Fe, Cu and Zn removal and for HDT of 2, 3, 4 and 6 days (HDT), moreover for Mn was necessary 4 and 6 days (HDT) and for Cr and Pb 6 days (HDT). (author)

  7. Workshop Report on Additive Manufacturing for Large-Scale Metal Components - Development and Deployment of Metal Big-Area-Additive-Manufacturing (Large-Scale Metals AM) System

    Energy Technology Data Exchange (ETDEWEB)

    Babu, Sudarsanam Suresh [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Manufacturing Demonstration Facility; Love, Lonnie J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Manufacturing Demonstration Facility; Peter, William H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Manufacturing Demonstration Facility; Dehoff, Ryan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Manufacturing Demonstration Facility

    2016-05-01

    ) systems development, (iv) material feedstock, (v) process planning, (vi) residual stress & distortion, (vii) post-processing, (viii) qualification of parts, (ix) supply chain and (x) business case. Furthermore, an open innovation network methodology was proposed to accelerate the development and deployment of new large-scale metal additive manufacturing technology with the goal of creating a new generation of high deposition rate equipment, affordable feed stocks, and large metallic components to enhance America’s economic competitiveness.

  8. [Investigation and analysis of heavy metal pollution related to soil-Panax notoginseng system].

    Science.gov (United States)

    Chen, Lu; Mi, Yan-Hua; Lin, Xin; Liu, Da-Hui; Zeng, Min; Chen, Xiao-Yan

    2014-07-01

    In this study, five heavy metals contamination of soil and different parts of Panax notoginseng in the plantation area was investigated. Analysis of heavy metals correlation between the planting soil and P. notoginseng; and the absorption and accumulation characteristics and translocation of soil heavy metals by P. notoginseng plants was revealed. Through field investigation and laboratory analytical methods, analysis of China's 30 different soil P. notoginseng origin and content of heavy metals in five different parts of the P. notoginseng plant content of heavy metals. The results revealed that the soil heavy metals should not be neglected in the plantation area Referring to the national soil quality standards (GB15608-1995), the excessive degree of soil heavy metals pollution showed Hg > As > Cd > Cr in the plantation area, and Pb content of soil was in the scope of the standard. Refer to 'Green Industry Standards for Import and Export of Medical Plants and Preparations', the excessive degree of heavy metals content of P. notoginseng plants showed As > Pb > Cr > Cd, and Hg content of plants was in the scope of the standard. Concentrations of five heavy metals of underground parts of P. notoginseng plants are higher than aboveground, and heavy metals elements are more concentrated in the root, followed by the rhizome of P. notoginseng plants. Heavy metal accumulation characteristics of the different parts of the P. notoginseng of the overall performance is the root > the rhizome > the root tuber > leaves > stems. From the point of view BCF value analysis of various parts of the P. notoginseng plants to absorb heavy metals in soil, BCF values of all samples were less than 1, description P. notoginseng not belong Hyperaccumulator. From the view of transportation and related analysis of the soil-P. notoginseng systems, the rhizome of P. notoginseng and the content of As and Cr in soil was significantly correlated, the root of P. notoginseng and the content of Cd in

  9. Study of thermosiphon and radiant panel passive heating systems for metal buildings

    Energy Technology Data Exchange (ETDEWEB)

    Biehl, F.A.; Schnurr, N.M.; Wray, W.O.

    1983-01-01

    A study of passive-heating systems appropriate for use on metal buildings is being conducted at Los Alamos National Laboratory for the Naval Civil Engineering Laboratory, Port Hueneme, California. The systems selected for study were chosen on the basis of their appropriateness for retrofit applications, although they are also suitable for new construction: simple radiant panels that communicate directly with the building interior and a backflow thermosiphon that provides heat indirectly.

  10. Superconductivity suppression near metal-dielectric in transition highly disordered systems

    International Nuclear Information System (INIS)

    Kuchinskij, Eh.Z.; Sadovskij, M.V.; Ehrkabaev, M.A.

    1997-01-01

    The effects of temperature suppression of superconducting transition T c within wide limits of disorders values from low-disordered to highly-disordered ones caused by formation of the Coulomb gap in the states density are studied on the bases of the earlier proposed self consistent theory on the metal-dielectric. It is shown that the proposed theory gives satisfactory description of experimental data for a number of the systems under study

  11. Failure of metals III: Fracture and fatigue of nanostructured metallic materials

    International Nuclear Information System (INIS)

    Pineau, André; Amine Benzerga, A.; Pardoen, Thomas

    2016-01-01

    Pushing the internal or external dimensions of metallic alloys down to the nanometer scale gives rise to strong materials, though most often at the expense of a low ductility and a low resistance to cracking, with negative impact on the transfer to engineering applications. These characteristics are observed, with some exceptions, in bulk ultra-fine grained and nanocrystalline metals, nano-twinned metals, thin metallic coatings on substrates and freestanding thin metallic films and nanowires. This overview encompasses all these systems to reveal commonalities in the origins of the lack of ductility and fracture resistance, in factors governing fatigue resistance, and in ways to improve properties. After surveying the various processing methods and key deformation mechanisms, we systematically address the current state of the art in terms of plastic localization, damage, static and fatigue cracking, for three classes of systems: (1) bulk ultra-fine grained and nanocrystalline metals, (2) thin metallic films on substrates, and (3) 1D and 2D freestanding micro and nanoscale systems. In doing so, we aim to favour cross-fertilization between progress made in the fields of mechanics of thin films, nanomechanics, fundamental researches in bulk nanocrystalline metals and metallurgy to impart enhanced resistance to fracture and fatigue in high-strength nanostructured systems. This involves exploiting intrinsic mechanisms, e.g. to enhance hardening and rate-sensitivity so as to delay necking, or improve grain-boundary cohesion to resist intergranular cracks or voids. Extrinsic methods can also be utilized such as by hybridizing the metal with another material to delocalize the deformation - as practiced in stretchable electronics. Fatigue crack initiation is in principle improved by a fine structure, but at the expense of larger fatigue crack growth rates. Extrinsic toughening through hybridization allows arresting or bridging cracks. The content and discussions are based on

  12. Standard Practice for Laboratory Screening of Metallic Containment Materials for Use With Liquids in Solar Heating and Cooling Systems

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1980-01-01

    1.1 This practice covers several laboratory test procedures for evaluating corrosion performance of metallic containment materials under conditions similar to those that may occur in solar heating and cooling systems. All test results relate to the performance of the metallic containment material only as a part of a metal/fluid pair. Performance in these laboratory test procedures, taken by itself, does not necessarily constitute an adequate basis for acceptance or rejection of a particular metal/fluid pair in solar heating and cooling systems, either in general or in a particular design. This practice is not intended to preclude the use of other screening tests, particularly when those tests are designed to more closely simulate field service conditions. 1.2 This practice describes apparatus and procedures for several tests, any one or more of which may be used to evaluate the deterioration of the metallic containment material in a metal/fluid pair. The procedures are designed to permit simulation, heating...

  13. The Alchemist’s Approach to Metal Poisoning: Transforming the Metal Burden

    Directory of Open Access Journals (Sweden)

    Wayne Briner

    2014-06-01

    Full Text Available Metal poisoning is a global problem with humans being exposed to a wide range of metals in varying doses and varying time frames. Traditionally, treatment involves removal of the toxic source or chelation therapy. An intermediate approach is needed. This review outlines the argument for the use of essential metal supplementation as a strategy to induce metallothionein expression and displace the toxic metal from important biological systems, improving the metal burden of the patient. Specific recommendations are given for supplementation with calcium, zinc and vitamin E as a broad strategy to improve the status of those exposed to toxic metals.

  14. Metal-rich, Metal-poor: Updated Stellar Population Models for Old Stellar Systems

    Science.gov (United States)

    Conroy, Charlie; Villaume, Alexa; van Dokkum, Pieter G.; Lind, Karin

    2018-02-01

    We present updated stellar population models appropriate for old ages (>1 Gyr) and covering a wide range in metallicities (‑1.5 ≲ [Fe/H] ≲ 0.3). These models predict the full spectral variation associated with individual element abundance variation as a function of metallicity and age. The models span the optical–NIR wavelength range (0.37–2.4 μm), include a range of initial mass functions, and contain the flexibility to vary 18 individual elements including C, N, O, Mg, Si, Ca, Ti, and Fe. To test the fidelity of the models, we fit them to integrated light optical spectra of 41 Galactic globular clusters (GCs). The value of testing models against GCs is that their ages, metallicities, and detailed abundance patterns have been derived from the Hertzsprung–Russell diagram in combination with high-resolution spectroscopy of individual stars. We determine stellar population parameters from fits to all wavelengths simultaneously (“full spectrum fitting”), and demonstrate explicitly with mock tests that this approach produces smaller uncertainties at fixed signal-to-noise ratio than fitting a standard set of 14 line indices. Comparison of our integrated-light results to literature values reveals good agreement in metallicity, [Fe/H]. When restricting to GCs without prominent blue horizontal branch populations, we also find good agreement with literature values for ages, [Mg/Fe], [Si/Fe], and [Ti/Fe].

  15. MetalS2: a tool for the structural alignment of minimal functional sites in metal-binding proteins and nucleic acids.

    Science.gov (United States)

    Andreini, Claudia; Cavallaro, Gabriele; Rosato, Antonio; Valasatava, Yana

    2013-11-25

    We developed a new software tool, MetalS(2), for the structural alignment of Minimal Functional Sites (MFSs) in metal-binding biological macromolecules. MFSs are 3D templates that describe the local environment around the metal(s) independently of the larger context of the macromolecular structure. Such local environment has a determinant role in tuning the chemical reactivity of the metal, ultimately contributing to the functional properties of the whole system. On our example data sets, MetalS(2) unveiled structural similarities that other programs for protein structure comparison do not consistently point out and overall identified a larger number of structurally similar MFSs. MetalS(2) supports the comparison of MFSs harboring different metals and/or with different nuclearity and is available both as a stand-alone program and a Web tool ( http://metalweb.cerm.unifi.it/tools/metals2/).

  16. CALIBRATION OF THE MEARTH PHOTOMETRIC SYSTEM: OPTICAL MAGNITUDES AND PHOTOMETRIC METALLICITY ESTIMATES FOR 1802 NEARBY M-DWARFS

    International Nuclear Information System (INIS)

    Dittmann, Jason A.; Irwin, Jonathan M.; Charbonneau, David; Newton, Elisabeth R.

    2016-01-01

    The MEarth Project is a photometric survey systematically searching the smallest stars near the Sun for transiting rocky planets. Since 2008, MEarth has taken approximately two million images of 1844 stars suspected to be mid-to-late M dwarfs. We have augmented this survey by taking nightly exposures of photometric standard stars and have utilized this data to photometrically calibrate the MEarth system, identify photometric nights, and obtain an optical magnitude with 1.5% precision for each M dwarf system. Each optical magnitude is an average over many years of data, and therefore should be largely immune to stellar variability and flaring. We combine this with trigonometric distance measurements, spectroscopic metallicity measurements, and 2MASS infrared magnitude measurements in order to derive a color–magnitude–metallicity relation across the mid-to-late M dwarf spectral sequence that can reproduce spectroscopic metallicity determinations to a precision of 0.1 dex. We release optical magnitudes and metallicity estimates for 1567 M dwarfs, many of which did not have an accurate determination of either prior to this work. For an additional 277 stars without a trigonometric parallax, we provide an estimate of the distance, assuming solar neighborhood metallicity. We find that the median metallicity for a volume-limited sample of stars within 20 pc of the Sun is [Fe/H] = −0.03 ± 0.008, and that 29/565 of these stars have a metallicity of [Fe/H] = −0.5 or lower, similar to the low-metallicity distribution of nearby G dwarfs. When combined with the results of ongoing and future planet surveys targeting these objects, the metallicity estimates presented here will be important for assessing the significance of any putative planet–metallicity correlation

  17. CALIBRATION OF THE MEARTH PHOTOMETRIC SYSTEM: OPTICAL MAGNITUDES AND PHOTOMETRIC METALLICITY ESTIMATES FOR 1802 NEARBY M-DWARFS

    Energy Technology Data Exchange (ETDEWEB)

    Dittmann, Jason A.; Irwin, Jonathan M.; Charbonneau, David; Newton, Elisabeth R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)

    2016-02-20

    The MEarth Project is a photometric survey systematically searching the smallest stars near the Sun for transiting rocky planets. Since 2008, MEarth has taken approximately two million images of 1844 stars suspected to be mid-to-late M dwarfs. We have augmented this survey by taking nightly exposures of photometric standard stars and have utilized this data to photometrically calibrate the MEarth system, identify photometric nights, and obtain an optical magnitude with 1.5% precision for each M dwarf system. Each optical magnitude is an average over many years of data, and therefore should be largely immune to stellar variability and flaring. We combine this with trigonometric distance measurements, spectroscopic metallicity measurements, and 2MASS infrared magnitude measurements in order to derive a color–magnitude–metallicity relation across the mid-to-late M dwarf spectral sequence that can reproduce spectroscopic metallicity determinations to a precision of 0.1 dex. We release optical magnitudes and metallicity estimates for 1567 M dwarfs, many of which did not have an accurate determination of either prior to this work. For an additional 277 stars without a trigonometric parallax, we provide an estimate of the distance, assuming solar neighborhood metallicity. We find that the median metallicity for a volume-limited sample of stars within 20 pc of the Sun is [Fe/H] = −0.03 ± 0.008, and that 29/565 of these stars have a metallicity of [Fe/H] = −0.5 or lower, similar to the low-metallicity distribution of nearby G dwarfs. When combined with the results of ongoing and future planet surveys targeting these objects, the metallicity estimates presented here will be important for assessing the significance of any putative planet–metallicity correlation.

  18. Marginal Accuracy of Castings Fabricated with Ringless Casting Investment System and Metal Ring Casting Investment System: A Comparative Study.

    Science.gov (United States)

    Kalavathi, M; Sachin, Bhuvana; Prasanna, B G; Shreeharsha, T V; Praveen, B; Ragher, Mallikarjuna

    2016-02-01

    The thermal expansion of the investment can be restricted by the metal casting ring because the thermal expansion of the ring is less than that of the investment. The ringless casting procedure is in use in clinical dentistry, though there is little scientific data to support its use in fixed partial dentures. In this study, marginal discrepancy of castings produced with the ringless casting technique and the conventional technique using the metal rings were compared. A total of 30 wax patterns were fabricated directly on a metal die. Optical stereomicroscope was used to measure the marginal discrepancy between the metal die and wax patterns. A total of 15 castings were invested using Bellavest T phosphate-bonded investment with the ringless technique and 15 were invested with the same investment with a metal ring; 30 castings were produced using a nickel-chromium ceramo-metal alloy. The internal surface of the castings was not modified and seated with finger pressure. The vertical marginal discrepancy was measured using an optical stereomicroscope at a magnification of 100x. The data obtained were statistically analyzed using students t-test (paired t-test and unpaired t-test). The castings of the ringless technique provided less vertical marginal discrepancy (240.56 ± 45.81 μ) than the castings produced with the conventional metal ring technique (281.98± 53.05 μ). The difference was statistically significant. The ringless casting technique had produced better marginal accuracy compared with conventional casting technique. Ringless casting system can be used routinely for clinical purpose.

  19. Highly sensitive colour change system within slight differences in metal ion concentrations based on homo-binuclear complex formation equilibrium for visual threshold detection of trace metal ions

    International Nuclear Information System (INIS)

    Mizuguchi, Hitoshi; Atsumi, Hiroshi; Hashimoto, Keigo; Shimada, Yasuhiro; Kudo, Yuki; Endo, Masatoshi; Yokota, Fumihiko; Shida, Junichi; Yotsuyanagi, Takao

    2004-01-01

    A new technique of expressing slight differences in metal ion concentrations by clear difference in colour was established for visual threshold detection of trace metal ions. The proposed method is based on rapid change of the mole fraction of the homo-binuclear complex (M 2 L) about a ligand in a narrow range of the total metal ion concentration (M T ) in a small excess, in case the second metal ion is bound to the reagent molecule which can bind two metal ions. Theoretical simulations showed that the highly sensitive colour change within slight differences in metal ion concentrations would be realized under the following conditions: (i) both of the stepwise formation constants of complex species are sufficiently large; (ii) the stepwise formation constant of the 1:1 complex (ML) is larger than that of M 2 L; and (iii) the absorption spectrum of M 2 L is far apart from the other species in the visible region. Furthermore, the boundary of the colour region in M T would be readily controlled by the total ligand concentration (L T ). Based on this theory, the proposed model was verified with the 3,3'-bis[bis(carboxymethyl)amino]methyl derivatives of sulphonephthalein dyes such as xylenol orange (XO), methylthymol blue (MTB), and methylxylenol blue (MXB), which can bind two metal ions at both ends of a π-electron conjugated system. The above-mentioned model was proved with the iron(III)-XO system at pH 2. In addition, MTB and MXB were suitable reagents for the visual threshold detection of trivalent metal ions such as iron(III), aluminium(III), gallium(III) and indium(III) ion in slightly acidic media. The proposed method has been applied successfully as a screening test for aluminium(III) ion in river water sampled at the downstream area of an old mine

  20. Metal Detector By Using PIC Microcontroller Interfacing With PC

    OpenAIRE

    Yin Min Theint; Myo Maung Maung; Hla Myo Tun

    2015-01-01

    Abstract This system proposes metal detector by using PIC microcontroller interfacing with PC. The system uses PIC microcontroller as the main controller whether the detected metal is ferrous metal or non-ferrous metal. Among various types of metal sensors and various types of metal detecting technologies concentric type induction coil sensor and VLF very low frequency metal detecting technology are used in this system. This system consists of two configurations Hardware configuration and Sof...

  1. Cutaneous and systemic hypersensitivity reactions to metallic implants

    DEFF Research Database (Denmark)

    Basko-Plluska, Juliana L; Thyssen, Jacob P; Schalock, Peter C

    2011-01-01

    Cutaneous reactions to metal implants, orthopedic or otherwise, are well documented in the literature. The first case of a dermatitis reaction over a stainless steel fracture plate was described in 1966. Most skin reactions are eczematous and allergic in nature, although urticarial, bullous....... However, other metal ions as well as bone cement components can cause such hypersensitivity reactions. To complicate things, patients may also develop delayed-type hypersensitivity reactions to metals (ie, in-stent restenosis, prosthesis loosening, inflammation, pain, or allergic contact dermatitis...

  2. Application of metal foam heat exchangers for a high-performance liquefied natural gas regasification system

    International Nuclear Information System (INIS)

    Kim, Dae Yeon; Sung, Tae Hong; Kim, Kyung Chun

    2016-01-01

    The intermediate fluid vaporizer has wide applications in the regasification of LNG (liquefied natural gas). The heat exchanger performance is one of the main contributors to the thermodynamic and cost effectiveness of the entire LNG regasification system. Within the paper, the authors discuss a new concept for a compact heat exchanger with a micro-cellular structure medium to minimize volume and mass and to increase thermal efficiency. Numerical calculations have been conducted to design a metal-foam filled plate heat exchanger and a shell-and-tube heat exchanger using published experimental correlations. The geometry of both heat exchangers was optimized using the conditions of thermolators in LNG regasification systems. The heat transfer and pressure drop performance was predicted to compare the heat exchangers. The results show that the metal-foam plate heat exchanger has the best performance at different channel heights and mass flow rates of fluid. In the optimized configurations, the metal-foam plate heat exchanger has a higher heat transfer rate and lower pressure drop than the shell-and-tube heat exchanger as the mass flow rate of natural gas is increased. - Highlights: • A metal foam heat exchanger is proposed for LNG regasification system. • Comparison was made with a shell and tube heat exchanger. • Heat transfer and pressure drop characteristics were estimated. • The geometry of both heat exchangers is optimized for thermolators. • It can be used as a compact and high performance thermolators.

  3. Refractory metal alloys and composites for space power systems

    International Nuclear Information System (INIS)

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

    1994-01-01

    Space power requirements for future NASA and other United States missions will range from a few kilowatts to megawatts of electricity. Maximum efficiency is a key goal of any power system in order to minimize weight and size so that the space shuttle may be used a minimum number of times to put the power supply into orbit. Nuclear power has been identified as the primary power source to meet these high levels of electrical demand. One method to achieve maximum efficiency is to operate the power supply, energy conversion system, and related components at relatively high temperatures. NASA Lewis Research Center has undertaken a research program on advanced technology of refractory metal alloys and composites that will provide base line information for space power systems in the 1900's and the 21st century. Basic research on the tensile and creep properties of fibers, matrices, and composites will be discussed

  4. Monitoring of heavy metals in selected Water Supply Systems in Poland, in relation to current regulations

    Science.gov (United States)

    Szuster-Janiaczyk, Agnieszka; Zeuschner, Piotr; Noga, Paweł; Skrzypczak, Marta

    2018-02-01

    The study presents an analysis of water quality monitoring in terms of the content of heavy metals, which is conducted in three independent water supply systems in Poland. The analysis showed that the monitoring of heavy metals isn't reliable - both the quantity of tested water samples and the location of the monitoring points are the problem. The analysis of changes in water quality from raw water to tap water was possible only for one of the analysed systems and indicate a gradual deterioration of water quality, although still within acceptable limits of legal regulations.

  5. COMPARISON OF APATITE II™ TREATMENT SYSTEM AT TWO MINES FOR METALS REMOVAL

    Science.gov (United States)

    Two abandoned lead-zinc mine sites, the Nevada Stewart Mine (NSM) and Success Mine, are located within the Coeur d'Alene Mining District, in northern Idaho. An Apatite II™ Treatment System (ATS) was implemented at each site to treat metal-laden water, mainly zinc. In the ATS, f...

  6. Metal is not inert: role of metal ions released by biocorrosion in aseptic loosening--current concepts.

    Science.gov (United States)

    Cadosch, Dieter; Chan, Erwin; Gautschi, Oliver P; Filgueira, Luis

    2009-12-15

    Metal implants are essential therapeutic tools for the treatment of bone fractures and joint replacements. The metals and metal alloys used in contemporary orthopedic and trauma surgery are well tolerated by the majority of patients. However, complications resulting from inflammatory and immune reactions to metal implants have been well documented. This review briefly discusses the different mechanisms of metal implant corrosion in the human body, which lead to the release of significant levels of metal ions into the peri-implant tissues and the systemic blood circulation. Additionally, this article reviews the effects of the released ions on bone metabolism and the immune system and discusses their involvement in the pathophysiological mechanisms of aseptic loosening and metal hypersensitivity in patients with metal implants.

  7. Accumulation status, sources and phytoavailability of metals in greenhouse vegetable production systems in Beijing, China.

    Science.gov (United States)

    Xu, Li; Lu, Anxiang; Wang, Jihua; Ma, Zhihong; Pan, Ligang; Feng, Xiaoyuan; Luan, Yunxia

    2015-12-01

    The accumulation status, sources and phytoavailability of selected metals in greenhouse vegetable production systems in peri-urban areas of Beijing were investigated. The mean concentrations of As, Cd, Cr, Hg and Pb in greenhouse soils were 8.44, 0.25, 69.0, 0.09 and 22.0 mg kg(-1), dw, respectively. According to principal component analysis, As, Cd, Cr and Hg are mainly from anthropogenic source, but Pb is likely from natural source. Metal concentrations in all vegetable samples were decreased in the order of Cr>As>Pb>Cd>Hg. Compared with root and fruit vegetables, leaf vegetables had relatively high concentrations and transfer factors of heavy metals, except for Cd. By including soil pH, OM and greenhouse soil metals, 10 empirical models were derived using stepwise multiple linear regression analysis to predict heavy metal concentrations in the edible parts of different vegetables. Among the different vegetable groups, the highest intakes of metals occurred through consumption of leaf vegetables for the two age groups, except for Cd. The HI value of the studied metals were all below 1, indicating that consumption of vegetables grown in greenhouse soils was of low risk to consumers in our study area. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Self-assembled systems of water soluble metal 8-hydroxyquinolates with surfactants and conjugated polyelectrolytes

    DEFF Research Database (Denmark)

    Burrows, Hugh D.; Costa, Telma; Luisa Ramos, M.

    2016-01-01

    We have studied the interaction of 8-hydroxyquinoline-5-sulfonate (8-HQS) with the metal ions Al(III) and Zn(II) in aqueous solution in the presence of tetraalkylammonium surfactants using UV/vis absorption, fluorescence, NMR spectroscopy and electrical conductivity measurements, complemented by ...... assembly between the conjugated polyelectrolyte and the metal/8-HQS complex, as demonstrated by electronic energy transfer. The potential of these systems in sensing, light harvesting, and electron injection/transport layers in organic semiconductor devices is discussed....

  9. Development of Geometry Normalized Electromagnetic System (GNES) instrument for metal defect detection

    Science.gov (United States)

    Zakaria, Zakaria; Surbakti, Muhammad Syukri; Syahreza, Saumi; Mat Jafri, Mohd. Zubir; Tan, Kok Chooi

    2017-10-01

    It has been already made, calibrated and tested a geometry normalized electromagnetic system (GNES) for metal defect examination. The GNES has an automatic data acquisition system which supporting the efficiency and accuracy of the measurement. The data will be displayed on the computer monitor as a graphic display then saved automatically in the Microsoft Excel format. The transmitter will transmit the frequency pair (FP) signals i.e. 112.5 Hz and 337.5 Hz; 112.5 Hz and 1012.5 Hz; 112.5 Hz and 3037.5 Hz; 337.5 Hz and 1012.5 Hz; 337.5 Hz and 3037.5 Hz. Simultaneous transmissions of two electromagnetic waves without distortions by the transmitter will induce an eddy current in the metal. This current, in turn, will produce secondary electromagnetic fields which are measured by the receiver together with the primary fields. Measurement of percent change of a vertical component of the fields will give the percent response caused by the metal or the defect. The response examinations were performed by the models with various type of defect for the master curves. The materials of samples as a plate were using Aluminum, Brass, and Copper. The more of the defects is the more reduction of the eddy current response. The defect contrasts were tended to decrease when the more depth of the defect position. The magnitude and phase of the eddy currents will affect the loading on the coil thus its impedance. The defect must interrupt the surface eddy current flow to be detected. Defect lying parallel to the current path will not cause any significant interruption and may not be detected. The main factors which affect the eddy current response are metal conductivity, permeability, frequency, and geometry.

  10. AN EXTREMELY CARBON-RICH, EXTREMELY METAL-POOR STAR IN THE SEGUE 1 SYSTEM

    International Nuclear Information System (INIS)

    Norris, John E.; Yong, David; Gilmore, Gerard; Wyse, Rosemary F. G.; Frebel, Anna

    2010-01-01

    We report the analysis of high-resolution, high signal-to-noise ratio, spectra of an extremely metal-poor, extremely C-rich red giant, Seg 1-7, in Segue 1-described in the literature alternatively as an unusually extended globular cluster or an ultra-faint dwarf galaxy. The radial velocity of Seg 1-7 coincides precisely with the systemic velocity of Segue 1, and its chemical abundance signature of [Fe/H] = -3.52, [C/Fe] = +2.3, [N/Fe] = +0.8, [Na/Fe] = +0.53, [Mg/Fe] = +0.94, [Al/Fe] = +0.23, and [Ba/Fe] < -1.0 is similar to that of the rare and enigmatic class of Galactic halo objects designated CEMP-no (carbon-rich, extremely metal-poor with no enhancement (over solar ratios) of heavy neutron-capture elements). This is the first star in a Milky Way 'satellite' that unambiguously lies on the metal-poor, C-rich branch of the Aoki et al. bimodal distribution of field halo stars in the ([C/Fe], [Fe/H])-plane. Available data permit us only to identify Seg 1-7 as a member of an ultra-faint dwarf galaxy or as debris from the Sgr dwarf spheroidal galaxy. In either case, this demonstrates that at extremely low abundance, [Fe/H ] <-3.0, star formation and associated chemical evolution proceeded similarly in the progenitors of both the field halo and satellite systems. By extension, this is consistent with other recent suggestions that the most metal-poor dwarf spheroidal and ultra-faint dwarf satellites were the building blocks of the Galaxy's outer halo.

  11. Role of neutron activation analysis in the study of heavy metal pollution of a lake-river system

    International Nuclear Information System (INIS)

    Filby, R.H.; Shah, K.R.; Funk, W.H.

    1974-01-01

    Details of a study of combined organic and metallic pollution of the Coeur d'Alene Lake-River and Spokane River system and the role played by nuclear techniques in the investigation are presented. The Coeur d'Alene River drains through the N. Idaho Pb--Zn mining region of Kellogg and the mining industry is the major source of metallic pollution of the lake and river system. The first part of the study has involved the determination of Pb, Zn, Ag, Cd, As, Cu, Sb, Co, Cr, Cs, Rb, Sc, Ba, Eu, La, Tb, Y, Zr, Fe, Mn, Mo, by INAA in waters, sediments and organisms throughout the region. Extremely high values for Pb, Zn, Sb, Fe and other metals were found in the Coeur d'Alene River delta sediments and in the lake sediments. Results from the study of metals in an aquatic ecosystem show the value of combining nuclear techniques with other methods of trace analysis in practical pollution problems

  12. Metal sponge for cryosorption pumping applications

    International Nuclear Information System (INIS)

    Myneni, G.R.; Kneisel, P.

    1995-01-01

    A system has been developed for adsorbing gases at high vacuum in a closed area. The system utilizes large surface clean anodized metal surfaces at low temperatures to adsorb the gases. The large surface clean anodized metal is referred to as a metal sponge. The metal sponge generates or maintains the high vacuum by increasing the available active cryosorbing surface area. 4 figs

  13. Effects of sulfate on heavy metal release from iron corrosion scales in drinking water distribution system.

    Science.gov (United States)

    Sun, Huifang; Shi, Baoyou; Yang, Fan; Wang, Dongsheng

    2017-05-01

    Trace heavy metals accumulated in iron corrosion scales within a drinking water distribution system (DWDS) could potentially be released to bulk water and consequently deteriorate the tap water quality. The objective of this study was to identify and evaluate the release of trace heavy metals in DWDS under changing source water conditions. Experimental pipe loops with different iron corrosion scales were set up to simulate the actual DWDS. The effects of sulfate levels on heavy metal release were systemically investigated. Heavy metal releases of Mn, Ni, Cu, Pb, Cr and As could be rapidly triggered by sulfate addition but the releases slowly decreased over time. Heavy metal release was more severe in pipes transporting groundwater (GW) than in pipes transporting surface water (SW). There were strong positive correlations (R 2  > 0.8) between the releases of Fe and Mn, Fe and Ni, Fe and Cu, and Fe and Pb. When switching to higher sulfate water, iron corrosion scales in all pipe loops tended to be more stable (especially in pipes transporting GW), with a larger proportion of stable constituents (mainly Fe 3 O 4 ) and fewer unstable compounds (β-FeOOH, γ-FeOOH, FeCO 3 and amorphous iron oxides). The main functional iron reducing bacteria (IRB) communities were favorable for the formation of Fe 3 O 4 . The transformation of corrosion scales and the growth of sulfate reducing bacteria (SRB) accounted for the gradually reduced heavy metal release with time. The higher metal release in pipes transporting GW could be due to increased Fe 6 (OH) 12 CO 3 content under higher sulfate concentrations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Liquid metal heat transfer issues

    International Nuclear Information System (INIS)

    Hoffman, H.W.; Yoder, G.L.

    1984-01-01

    An alkali liquid metal cooled nuclear reactor coupled with an alkali metal Rankine cycle provides a practicable option for space systems/missions requiring power in the 1 to 100 MW(e) range. Thermal issues relative to the use of alkali liquid metals for this purpose are identified as these result from the nature of the alkali metal fluid itself, from uncertainties in the available heat transfer correlations, and from design and performance requirements for system components operating in the earth orbital microgravity environment. It is noted that, while these issues require further attention to achieve optimum system performance, none are of such magnitude as to invalidate this particular space power concept

  15. Cutaneous and systemic hypersensitivity reactions to metallic implants.

    Science.gov (United States)

    Basko-Plluska, Juliana L; Thyssen, Jacob P; Schalock, Peter C

    2011-01-01

    Cutaneous reactions to metal implants, orthopedic or otherwise, are well documented in the literature. The first case of a dermatitis reaction over a stainless steel fracture plate was described in 1966. Most skin reactions are eczematous and allergic in nature, although urticarial, bullous, and vasculitic eruptions may occur. Also, more complex immune reactions may develop around the implants, resulting in pain, inflammation, and loosening. Nickel, cobalt, and chromium are the three most common metals that elicit both cutaneous and extracutaneous allergic reactions from chronic internal exposure. However, other metal ions as well as bone cement components can cause such hypersensitivity reactions. To complicate things, patients may also develop delayed-type hypersensitivity reactions to metals (ie, in-stent restenosis, prosthesis loosening, inflammation, pain, or allergic contact dermatitis) following the insertion of intravascular stents, dental implants, cardiac pacemakers, or implanted gynecologic devices. Despite repeated attempts by researchers and clinicians to further understand this difficult area of medicine, the association between metal sensitivity and cutaneous allergic reactions remains to be fully understood. This review provides an update of the current knowledge in this field and should be valuable to health care providers who manage patients with conditions related to this field.

  16. The nonmetal-metal transition in solutions of metals in molten salts

    International Nuclear Information System (INIS)

    Tosi, M.P.

    1997-04-01

    Solutions of metals in molten salts present a rich phenomenology: localization of electrons in disordered ionic media, activated electron transport increasing with metal concentration towards a nonmetal-metal (NM-M) transition, and liquid-liquid phase separation. A brief review of progress in the study of these systems is given in this article, with main focus on the NM-M transition. After recalling the known NM-M behaviour of the component elements in the case of expanded fluid alkali metals and mercury and of solid halogens under pressure, the article focuses on liquid metal - molten salt solutions and traces the different NM-M behaviours of the alkalis in their halides and of metals added to polyvalent metal halides. (author). 51 refs, 2 figs

  17. Heavy metal adsorptivity of calcium-alginate-modified diethylenetriamine-silica gel and its application to a flow analytical system using flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Mori, Masanobu; Suzuki, Toshinobu; Sugita, Tsuyoshi; Nagai, Daisuke; Hirayama, Kazuo; Onozato, Makoto; Itabashi, Hideyuki

    2014-01-01

    Highlights: • Calcium-alginate-modified dien-silica gel adsorbed multivalent metal ions. • Metal ions adsorbed on CaAD were eluted using low acidic concentrations. • Flow system with CaAD-packed column enriched metal concentrations up to 50-fold. - Abstract: This study aimed to evaluate the heavy metal adsorptivity of calcium-alginate-modified diethylenetriamine-silica gel (CaAD) and incorporate this biosorbent into a flow analytical system for heavy metal ions using flame atomic absorption spectrometry (FAAS). The biosorbent was synthesized by electrostatically coating calcium alginate onto diethylenetriamine (dien)-silica gel. Copper ion adsorption tests by a batch method showed that CaAD exhibited a higher adsorption rate compared with other biosorbents despite its low maximum adsorption capacity. Next, CaAD was packed into a 1 mL microcolumn, which was connected to a flow analytical system equipped with an FAAS instrument. The flow system quantitatively adsorbed heavy metals and enriched their concentrations. This quantitative adsorption was achieved for pH 3–4 solutions containing 1.0 × 10 −6 M of heavy metal ions at a flow rate of 5.0 mL min −1 . Furthermore, the metal ions were successfully desorbed from CaAD at low nitric acid concentrations (0.05–0.15 M) than from the polyaminecarboxylic acid chelating resin (Chelex 100). Therefore, CaAD may be considered as a biosorbent that quickly adsorbs and easily desorbs analyte metal ions. In addition, the flow system enhanced the concentrations of heavy metals such as Cu 2+ , Zn 2+ , and Pb 2+ by 50-fold. This new enrichment system successfully performed the separation and determination of Cu 2+ (5.0 × 10 −8 M) and Zn 2+ (5.7 × 10 −8 M) in a river water sample and Pb 2+ (3.8 × 10 −9 M) in a ground water sample

  18. Light metal production

    Science.gov (United States)

    Fan, Qinbai

    2016-04-19

    An electrochemical process for the production of light metals, particularly aluminum. Such a process involves contacting a light metal source material with an inorganic acid to form a solution containing the light metal ions in high concentration. The solution is fed to an electrochemical reactor assembly having an anode side containing an anode and a cathode side containing a cathode, with anode side and the cathode side separated by a bipolar membrane, with the solution being fed to the anode side. Light metal ions are electrochemically transferred through the bipolar membrane to the cathode side. The process further involves reducing the light metal ions to light metal powder. An associated processing system is also provided.

  19. Resonant Auger studies of metallic systems

    International Nuclear Information System (INIS)

    Coulthard, I.; Antel, W. J. Jr.; Frigo, S. P.; Freeland, J. W.; Moore, J.; Calaway, W. S.; Pellin, M. J.; Mendelsohn, M.; Sham, T. K.; Naftel, S. J.

    2000-01-01

    Results of resonant Auger spectroscopy experimental are presented for Cu, Co, and oxidized Al. Sublifetime narrowing of Auger spectra and generation of sublifetime narrowed absorption spectra constructed from Auger yield measurements were observed. Resonant Auger yields are used to identify three chemical states of oxidized Al. Partial absorption yield spectra were derived giving detailed electronic information and thickness information for the various chemical states of the bulk metal, the passivating aluminum oxide layer, and the metal-oxide interface region. In addition, the total absorption yield spectrum for the oxidized Al sample was constructed from the partial yield data, supporting the consistency of our method. (c) 2000 American Vacuum Society

  20. Phase 1 study of metallic cask systems for spent fuel management from reactor to repository. Volume I. Phase 1 study summary

    International Nuclear Information System (INIS)

    1986-02-01

    It was proposed to perform a systems evaluation of metallic cask systems in order to define and examine the use of various metallic cask concepts or combination of concepts for the overall inventory management of spent fuel starting with its discharge from reactors to its emplacement in geologic repositories. This systems evaluation occurs in three phases. This three phase systems evaluation leads to a definition and recommendation of a sound and practical metallic cask system to accomplish efficient and effective management of spent fuel in the back end of the nuclear fuel cycle. Phase 1 Study objectives: establish system-wide functional criteria and assumptions; perform the systems engineering needed to define the metallic cask concepts and their feasibility; perform a screening evaluation of the technical and economic merits of the concepts; and recommend those to be included for a more detailed systems evaluation in Phase 2. Phase 2 Study objectives: refine the system-wide functional criteria and assumptions; perform the design engineering needed to enhance the validity and workability of those concepts recommended in Phase 1; and perform a more detailed systems evaluation. Phase 3 Study objectives: conclude the systems evaluation and develop an implementation plan. Volume I presents an overview of the detailed systems evaluation presented in Volume II

  1. Peroxotitanates for Biodelivery of Metals

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, David; Elvington, M.

    2009-02-11

    Metal-based drugs are largely undeveloped in pharmacology. One limiting factor is the systemic toxicity of metal-based compounds. A solid-phase, sequestratable delivery agent for local delivery of metals could reduce systemic toxicity, facilitating new drug development in this nascent area. Amorphous peroxotitanates (APT) are ion exchange materials with high affinity for several heavy metal ions, and have been proposed to deliver or sequester metal ions in biological contexts. In the current study, we tested a hypothesis that APT are able to deliver metals or metal compounds to cells. We exposed fibroblasts (L929) or monocytes (THP1) to metal-APT materials for 72 h in vitro, then measured cellular mitochondrial activity (SDH-MTT method) to assess the biological impact of the metal-APT materials vs. metals or APT alone. APT alone did not significantly affect cellular mitochondrial activity, but all metal-APT materials suppressed the mitochondrial activity of fibroblasts (by 30-65% of controls). The concentration of metal-APT materials required to suppress cellular mitochondrial activity was below that required for metals alone, suggesting that simple extracellular release of the metals from the metal-APT materials was not the primary mechanism of mitochondrial suppression. In contrast to fibroblasts, no metal-APT material had a measurable effect on THP1 monocyte mitochondrial activity, despite potent suppression by metals alone. This latter result suggested that 'biodelivery' by metal-APT materials may be cell type-specific. Therefore, it appears that APT are plausible solid phase delivery agents of metals or metal compounds to some types of cells for potential therapeutic effect.

  2. The one-particle scenario for the metal-insulator transition in two-dimensional systems at T = 0

    CERN Document Server

    Tarasov, Y V

    2003-01-01

    The conductance of bounded disordered electron systems is calculated by reducing the original dynamic problem of arbitrary dimensionality to a set of strictly one-dimensional problems for one-particle mode propagators. The metallic ground state of a two-dimensional conductor, which is considered as a limiting case of three-dimensional quantum waveguide, is shown to result from its multi-modeness. As the waveguide thickness is reduced, e.g., by applying a 'pressing' potential, the electron system undergoes a set of continuous phase transitions related to discrete variations of the number of extended modes. The closing of the last current carrying mode is regarded as a phase transition of the electron system from metallic to dielectric state. The obtained results agree qualitatively with the observed 'anomalies' of resistivity of different two-dimensional electron and hole systems.

  3. Heavy Metals Levels in Soil and Vegetables in Different Growing Systems

    Directory of Open Access Journals (Sweden)

    Hura C.

    2013-04-01

    Full Text Available The current project deals with an issue of actuality and scientific/technical necessity and aims to assess the factors contributing to the vulnerability of ecological systems and therefore endangering/compromising food safety. The goals of this ongoing study are to address the main risk factors on ecological system with particular regards to fresh growing vegetables and to establish technical monitoring system(s with a view to increase food safety. Herein, the authors present the research results obtained in 2011 in SIECOLEG Project regarding the assessment of some heavy metals (mainly lead, cadmium, cooper, and manganese of 80 samples soils and 25 samples vegetables from some ecological system. The concentrations of heavy metals were measured by Atomic absorption spectrometer (AAS Schimadzu 6300 - with graphite furnace atomizer and autosampler. In soil: lead and cadmium concentrations ranged from 4.51 to 6.58 mg/kg and from 0.14 to 0.4 mg/kg, respectively. Cooper and manganese concentrations ranged from 20.73 to 6.58 mg/kg and from 218.1 to 298.3 mg/kg, respectively. In vegetables (tomatoes, cucumber, peppers, eggplant, cabbage: lead concentrations ranged from 0.0 (tomatoes to 4.35 mg/kg (cabbage; cooper concentrations ranged from 0.2 mg/kg (cucumber to 0.80 mg/kg (eggplant; manganese concentrations ranged from 0.0 mg/kg (tomatoes to 0.60 mg/kg (eggplant. Cadmium was not detected in any of analysed vegetable samples. Under these circumstances, the project intends to demonstrate the extent of this vulnerability and to elaborate measures for controlling and diminishing the effects of the involved factors in order to increase food safety and security for ecological fresh vegetables

  4. Motion Planning for a Direct Metal Deposition Rapid Prototyping System

    Energy Technology Data Exchange (ETDEWEB)

    AMES,ARLO L.; HENSINGER,DAVID M.; KUHLMANN,JOEL L.

    1999-10-18

    A motion planning strategy was developed and implemented to generate motion control instructions from solid model data for controlling a robotically driven solid free-form fabrication process. The planning strategy was tested using a PUMA type robot arm integrated into a LENS{trademark} (Laser Engineered Net Shape) system. Previous systems relied on a series of x, y, and z stages, to provide a minimal coordinated motion control capability. This limited the complexity of geometries that could be constructed. With the coordinated motion provided by a robotic arm, the system can produce three dimensional parts by ''writing'' material onto any face of existing material. The motion planning strategy relied on solid model geometry evaluation and exploited robotic positioning flexibility to allow the construction of geometrically complex parts. The integration of the robotic manipulator into the LENS{trademark} system was tested by producing metal parts directly from CAD models.

  5. Natural microbial system for heavy metals cleanup application

    African Journals Online (AJOL)

    compq

    2012-05-24

    May 24, 2012 ... metallurgy and other chemical industries lead to the discharge of ... the direct metal-microbe interaction become less effective .... bio-essential micronutrients as zinc, manganese, iron, cobalt ... 0.9 to 1.1), variable capabilities of cadmium precipitation .... Metals, minerals and microbes: Geomicrobiology and.

  6. Metals extraction from sea water

    International Nuclear Information System (INIS)

    Chryssostomidis, C.; Larue, G.J.; Morgan, D.T.

    1981-01-01

    A method and system for continuously extracting metals from sea water by deploying adsorber sheets in a suitable current of sea water, recovering the adsorber sheets after they become loaded with metal and eluting the metal from the recovered sheets. The system involves the use of hollow, perforated bobbins on which the sheets are rolled as they are recovered and through which elutant is introduced

  7. Metal ion concentrations in body fluids after implantation of hip replacements with metal-on-metal bearing--systematic review of clinical and epidemiological studies.

    Directory of Open Access Journals (Sweden)

    Albrecht Hartmann

    Full Text Available INTRODUCTION: The use of metal-on-metal (MoM total hip arthroplasty (THA increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. OBJECTIVE: To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. METHODS: Systematic review of clinical trials (RCTs and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor, patient characteristics as well as study quality characteristics (secondary explanatory factors. RESULTS: Overall, 104 studies (11 RCTs, 93 epidemiological studies totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L. Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. DISCUSSION: Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed "time out" for stemmed large-head MoM-THA and recommend a restricted

  8. Metallosis: A diagnosis not only in patients with metal-on-metal prostheses

    International Nuclear Information System (INIS)

    Oliveira, Catarina A.; Candelária, Isabel S.; Oliveira, Pedro B.; Figueiredo, Antonio; Caseiro-Alves, Filipe

    2014-01-01

    Although the real actual incidence of metallosis is unknown, it is described as a rare diagnosis with a 5% estimated incidence in the hip prosthetic replacements. The adoption of non-metallic articular prosthetic devices, made of polyethylene and ceramic, is the main reason to the diminishing number of reported cases. We present a case of metallosis with a clinical systemic presentation in a patient with a non-metallic hip prosthesis, which occurred due to a fracture of the acetabular liner component, leading to abnormal metal–metal contact. The metallic debris leads to a massive local and systemic release of cytokines. Revision is necessary whenever osteolysis and loosening of the prosthesis occur. Imaging evaluation, especially CT, has a central role in diagnosis and planning the surgical treatment

  9. PHYSICAL BASES OF SYSTEMS CREATION FOR MAGNETIC-IMPULSIVE ATTRACTION OF THIN-WALLED SHEET METALS

    Directory of Open Access Journals (Sweden)

    Y. Batygin

    2009-01-01

    Full Text Available The work is dedicated to the physical base of systems creating for the thin-walled sheet metals magnetic pulse attraction. Some practical realization models of the author’s suggestions are represented.

  10. Metal-based nanoparticle interactions with the nervous system: the challenge of brain entry and the risk of retention in the organism.

    Science.gov (United States)

    Yokel, Robert; Grulke, Eric; MacPhail, Robert

    2013-01-01

    This review of metal-based nanoparticles focuses on factors influencing their distribution into the nervous system, evidence they enter brain parenchyma, and nervous system responses. Gold is emphasized as a model metal-based nanoparticle and for risk assessment in the companion review. The anatomy and physiology of the nervous system, basics of colloid chemistry, and environmental factors that influence what cells see are reviewed to provide background on the biological, physical-chemical, and internal milieu factors that influence nervous system nanoparticle uptake. The results of literature searches reveal little nanoparticle research included the nervous system, which about equally involved in vitro and in vivo methods, and very few human studies. The routes of uptake into the nervous system and mechanisms of nanoparticle uptake by cells are presented with examples. Brain nanoparticle uptake inversely correlates with size. The influence of shape has not been reported. Surface charge has not been clearly shown to affect flux across the blood-brain barrier. There is very little evidence for metal-based nanoparticle distribution into brain parenchyma. Metal-based nanoparticle disruption of the blood-brain barrier and adverse brain changes have been shown, and are more pronounced for spheres than rods. Study concentrations need to be put in exposure contexts. Work with dorsal root ganglion cells and brain cells in vitro show the potential for metal-based nanoparticles to produce toxicity. Interpretation of these results must consider the ability of nanoparticles to distribute across the barriers protecting the nervous system. Effects of the persistence of poorly soluble metal-based nanoparticles are of particular concern. Copyright © 2013 Wiley Periodicals, Inc.

  11. [Continuous remediation of heavy metal contaminated soil by co-cropping system enhanced with chelator].

    Science.gov (United States)

    Wei, Ze-Bin; Guo, Xiao-Fang; Wu, Qi-Tang; Long, Xin-Xian

    2014-11-01

    In order to elucidate the continuous effectiveness of co-cropping system coupling with chelator enhancement in remediating heavy metal contaminated soils and its environmental risk towards underground water, soil lysimeter (0.9 m x 0.9 m x 0.9 m) experiments were conducted using a paddy soil affected by Pb and Zn mining in Lechang district of Guangdong Province, 7 successive crops were conducted for about 2.5 years. The treatments included mono-crop of Sedum alfredii Hance (Zn and Cd hyperaccumulator), mono-crop of corn (Zea mays, cv. Yunshi-5, a low-accumulating cultivar), co-crop of S. alfredii and corn, and co-crop + MC (Mixture of Chelators, comprised of citric acid, monosodium glutamate waste liquid, EDTA and KCI with molar ratio of 10: 1:2:3 at the concentration of 5 mmol x kg(-1) soil). The changes of heavy metal concentrations in plants, soil and underground water were monitored. Results showed that the co-cropping system was suitable only in spring-summer seasons and significantly increased Zn and Cd phytoextraction. In autumn-winter seasons, the growth of S. alfredii and its phytoextraction of Zn and Cd were reduced by co-cropping and MC application. In total, the mono-crops of S. alfredii recorded a highest phytoextraction of Zn and Cd. However, the greatest reduction of soil Zn, Cd and Pb was observed with the co-crop + MC treatment, the reduction rates were 28%, 50%, and 22%, respectively, relative to the initial soil metal content. The reduction of this treatment was mainly attributed to the downwards leaching of metals to the subsoil caused by MC application. The continuous monitoring of leachates during 2. 5 year's experiment also revealed that the addition of MC increased heavy metal concentrations in the leaching water, but they did not significantly exceed the III grade limits of the underground water standard of China.

  12. Design of Embedded Metal Catalysts via Reverser Micro-Emulsion System: a Way to Suppress Catalyst Deactivation by Metal Sintering

    KAUST Repository

    AlMana, Noor

    2016-06-19

    The development of highly selective and active, long-lasting, robust, low-cost and environmentally benign catalytic materials is the greatest challenge in the area of catalysis study. In this context, core-shell structures where the active sites are embedded inside the protecting shell have attracted a lot of researchers working in the field of catalysis owing to their enhanced physical and chemical properties suppress catalyst deactivation. Also, a new active site generated at the interface between the core and shell may increases the activity and efficiency of the catalyst in catalytic reactions especially for oxide shells that exhibit redox properties such as TiO2 and CeO2. Moreover, coating oxide layer over metal nanoparticles (NPs) can be designed to provide porosity (micropore/mesopore) that gives selectivity of the various reactants by the different gas diffusion rates. In this thesis, we will discuss the concept of catalyst stabilization against metal sintering by a core-shell system. In particular we will study the mechanistic of forming core-shell particles and the key parameters that can influence the properties and morphology of the Pt metal particle core and SiO2 shell (Pt@SiO2) using the reverse micro-emulsion method. The Pt@SiO2 core-shell catalysts were investigated for low-temperature CO oxidation reaction. The study was further extended to other catalytic applications by varying the composition of the core as well as the chemical nature of the shell material. The Pt NPs were embedded within another oxide matrix such as ZrO2 and TiO2 for CO oxidation reaction. These materials were studied in details to identify the factors governing the coating of the oxide around the metal NPs. Next, a more challenging system, namely, bimetallic Ni9Pt NPs embedded in TiO2 and ZrO2 matrix were investigated for dry reforming of methane reaction at high temperatures. The challenges of designing Ni9Pt@oxide core-shell structure with TiO2 and ZrO2 and their tolerance

  13. Optical transmission theory for metal-insulator-metal periodic nanostructures

    Directory of Open Access Journals (Sweden)

    Blanchard-Dionne Andre-Pierre

    2016-11-01

    Full Text Available A semi-analytical formalism for the optical properties of a metal-insulator-metal periodic nanostructure using coupled-mode theory is presented. This structure consists in a dielectric layer in between two metallic layers with periodic one-dimensional nanoslit corrugation. The model is developed using multiple-scattering formalism, which defines transmission and reflection coefficients for each of the interface as a semi-infinite medium. Total transmission is then calculated using a summation of the multiple paths of light inside the structure. This method allows finding an exact solution for the transmission problem in every dimension regime, as long as a sufficient number of diffraction orders and guided modes are considered for the structure. The resonant modes of the structure are found to be related to the metallic slab only and to a combination of both the metallic slab and dielectric layer. This model also allows describing the resonant behavior of the system in the limit of a small dielectric layer, for which discontinuities in the dispersion curves are found. These discontinuities result from the out-of-phase interference of the different diffraction orders of the system, which account for field interaction for both inner interfaces of the structure.

  14. Exploring multi-metal biosorption by indigenous metal-hyperresistant Enterobacter sp. J1 using experimental design methodologies

    International Nuclear Information System (INIS)

    Lu, W.-B.; Kao, W.-C.; Shi, J.-J.; Chang, J.-S.

    2008-01-01

    A novel experimental design, combining mixture design and response surface methodology (RSM), was developed to investigate the competitive adsorption behavior of lead, copper and cadmium by an indigenous isolate Enterobacter sp. J1 able to tolerate high concentrations of a variety of heavy metals. Using the proposed combinative experimental design, two different experiment designs in a ternary metal biosorption system can be integrated to a succinct experiment and the number of experimental trials was markedly reduced from 38 to 26 by reusing the mutual experimental data. Triangular contour diagrams and triangular three-dimensional surface plots were generated to describe the ternary metal biosorption equilibrium data in mixture design systems. The results show that the preference of metal sorption of Enterobacter sp. J1 decreased in the order of Pb 2+ > Cu 2+ > Cd 2+ . The presence of other metals resulted in a competitive effect. The influence of the other two metals in ternary metal biosorption system can be easily determined by comparing the stray distance from the single metal biosorption. The behavior of competitive biosorption was successfully described and predicted using a combined Langmuir-Freundlich model along with new three-dimensional contour-surface plots

  15. Exploring multi-metal biosorption by indigenous metal-hyperresistant Enterobacter sp. J1 using experimental design methodologies

    Energy Technology Data Exchange (ETDEWEB)

    Lu, W.-B. [Department of Cosmetic Science, Chung Hwa University of Medical Technology, Tainan, Taiwan (China); Kao, W.-C.; Shi, J.-J. [Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan (China); Chang, J.-S. [Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan (China)], E-mail: changjs@mail.ncku.edu.tw

    2008-05-01

    A novel experimental design, combining mixture design and response surface methodology (RSM), was developed to investigate the competitive adsorption behavior of lead, copper and cadmium by an indigenous isolate Enterobacter sp. J1 able to tolerate high concentrations of a variety of heavy metals. Using the proposed combinative experimental design, two different experiment designs in a ternary metal biosorption system can be integrated to a succinct experiment and the number of experimental trials was markedly reduced from 38 to 26 by reusing the mutual experimental data. Triangular contour diagrams and triangular three-dimensional surface plots were generated to describe the ternary metal biosorption equilibrium data in mixture design systems. The results show that the preference of metal sorption of Enterobacter sp. J1 decreased in the order of Pb{sup 2+} > Cu{sup 2+} > Cd{sup 2+}. The presence of other metals resulted in a competitive effect. The influence of the other two metals in ternary metal biosorption system can be easily determined by comparing the stray distance from the single metal biosorption. The behavior of competitive biosorption was successfully described and predicted using a combined Langmuir-Freundlich model along with new three-dimensional contour-surface plots.

  16. Metal-insulator transitions

    Science.gov (United States)

    Imada, Masatoshi; Fujimori, Atsushi; Tokura, Yoshinori

    1998-10-01

    Metal-insulator transitions are accompanied by huge resistivity changes, even over tens of orders of magnitude, and are widely observed in condensed-matter systems. This article presents the observations and current understanding of the metal-insulator transition with a pedagogical introduction to the subject. Especially important are the transitions driven by correlation effects associated with the electron-electron interaction. The insulating phase caused by the correlation effects is categorized as the Mott Insulator. Near the transition point the metallic state shows fluctuations and orderings in the spin, charge, and orbital degrees of freedom. The properties of these metals are frequently quite different from those of ordinary metals, as measured by transport, optical, and magnetic probes. The review first describes theoretical approaches to the unusual metallic states and to the metal-insulator transition. The Fermi-liquid theory treats the correlations that can be adiabatically connected with the noninteracting picture. Strong-coupling models that do not require Fermi-liquid behavior have also been developed. Much work has also been done on the scaling theory of the transition. A central issue for this review is the evaluation of these approaches in simple theoretical systems such as the Hubbard model and t-J models. Another key issue is strong competition among various orderings as in the interplay of spin and orbital fluctuations. Experimentally, the unusual properties of the metallic state near the insulating transition have been most extensively studied in d-electron systems. In particular, there is revived interest in transition-metal oxides, motivated by the epoch-making findings of high-temperature superconductivity in cuprates and colossal magnetoresistance in manganites. The article reviews the rich phenomena of anomalous metallicity, taking as examples Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Ru compounds. The diverse phenomena include strong spin and

  17. Preparation and Characterization of Styrene Bearing Diethanolamine Side Group, Styrene Copolymer Systems, and Their Metal Complexes

    Directory of Open Access Journals (Sweden)

    Aslışah Açıkses

    2018-01-01

    Full Text Available The two copolymer systems of styrene bearing diethanol amine side group and styrene were prepared by free radical polymerization method at 60°C in presence of 1,4-dioxane as solvent and AIBN as initiator. Their metal complexes were prepared by reaction of the copolymer used as ligand P(DEAMSt-co-StL′′ and Ni(II and Co(II metal ions, which was carried out in presence of ethanol and NaOH at 65°C for 48 h in pH = 7.5. The structures of the copolymers used as ligand and metal complexes were identified by FT-IR, 1H-NMR spectra, and elemental analysis. The properties of the copolymers used as ligand and metal complexes were characterized by SEM-EDX, AAS, DSC, TGA, and DTA techniques. Then, the electrical properties of the copolymers and metal complexes were examined as a function of the temperature and frequency, and the activation energies (Ea were estimated with conductivity measurements.

  18. A magnetic investigation of phase transitions for metal-hydrogen systems based on nickel by means of computer-aided data acquisition

    International Nuclear Information System (INIS)

    Martin, W.E.

    1986-01-01

    In the present thesis the magnetic behaviour of Nickel-based metal-hydrogen systems is investigated in relation to its background in metal physics, in order to get information on the formation and the decomposition of metal-hydrogen phases. The magnetic investigations are performed at the systems Ni-Cu-H and Ni-Cr-H with Cu up to 40 at% and Cr up to 7 at%. The differential susceptibility is measured during hydration and decomposition of hydrides and the connection between magnetic moment and hydrogen concentration is discussed. (BHO)

  19. Bed geometries, fueling strategies and optimization of heat exchanger designs in metal hydride storage systems for automotive applications: A review

    DEFF Research Database (Denmark)

    Mazzucco, Andrea; Dornheim, Martin; Sloth, Michael

    2014-01-01

    This review presents recent developments for effective heat management systems to be integrated in metal hydride storage tanks, and investigates the performance improvements and limitations of each particular solution. High pressures and high temperatures metal hydrides can lead to different design...... given to metal hydride storage tanks for light duty vehicles, since this application is the most promising one for such storage materials and has been widely studied in the literature. Enhancing cooling/heating during hydrogen uptake and discharge has found to be essential to improve storage systems...

  20. Bacterial metal resistance genes and metal bioavailability in contaminated sediments

    International Nuclear Information System (INIS)

    Roosa, Stéphanie; Wattiez, Ruddy; Prygiel, Emilie; Lesven, Ludovic; Billon, Gabriel; Gillan, David C.

    2014-01-01

    In bacteria a metal may be defined as bioavailable if it crosses the cytoplasmic membrane to reach the cytoplasm. Once inside the cell, specific metal resistance systems may be triggered. In this research, specific metal resistance genes were used to estimate metal bioavailability in sediment microbial communities. Gene levels were measured by quantitative PCR and correlated to metals in sediments using five different protocols to estimate dissolved, particle-adsorbed and occluded metals. The best correlations were obtained with czcA (a Cd/Zn/Co efflux pump) and Cd/Zn adsorbed or occluded in particles. Only adsorbed Co was correlated to czcA levels. We concluded that the measurement of czcA gene levels by quantitative PCR is a promising tool which may complement the classical approaches used to estimate Cd/Zn/Co bioavailability in sediment compartments. - Highlights: • Metal resistance genes were used to estimate metal bioavailability in sediments. • Gene levels were correlated to metals using 5 different metal extraction protocols. • CzcA gene levels determined by quantitative PCR is a promising tool for Cd/Zn/Co. - Capsule Bacterial czcA is a potential biomarker of Cd, Zn and Co bioavailability in aquatic sediments as shown by quantitative PCR and sequential metal extraction

  1. The tribology of metal-on-metal total hip replacements.

    Science.gov (United States)

    Scholes, S C; Unsworth, A

    2006-02-01

    Total hip surgery is an effective way of alleviating the pain and discomfort caused by diseased or damaged joints. However, in the majority of cases, these joints have a finite life. The main reason for failure is osteolysis (bone resorption). It is well documented that an important cause of osteolysis, and therefore the subsequent loosening and failure of conventional metal- or ceramic-on-ultra-high molecular weight polyethylene joints, is the body's immunological response to the polyethylene wear particles. To avoid this, interest has been renewed in metal-on-metal joints. The intention of this paper is to review the studies that have taken place within different laboratories to determine the tribological performance of new-generation metal-on-metal total hip replacements. These types of joint offer a potential solution to enhance the longevity of prosthetic hip systems; however, problems may arise owing to the effects of metal ion release, which are, as yet, not fully understood.

  2. Evaluation of Additively Manufactured Metals for Use in Oxygen Systems Project

    Science.gov (United States)

    Tylka, Jonathan; Cooper, Ken; Peralta, Stephen; Wilcutt, Terrence; Hughitt, Brian; Generazio, Edward

    2016-01-01

    Space Launch System, Commercial Resupply, and Commercial Crew programs have published intent to use additively manufactured (AM) components in propulsion systems and are likely to include various life support systems in the future. Parts produced by these types of additive manufacturing techniques have not been fully evaluated for use in oxygen systems and the inherent risks have not been fully identified. Some areas of primary concern in the SLS process with respect to oxygen compatibility may be the porosity of the printed parts, fundamental differences in microstructure of an AM part as compared to traditional materials, or increased risk of shed metal particulate into an oxygen system. If an ignition were to occur the printed material could be more flammable than components manufactured from a traditional billet of raw material and/or present a significant hazards if not identified and rigorously studied in advance of implementation into an oxygen system.

  3. Metal Detector By Using PIC Microcontroller Interfacing With PC

    Directory of Open Access Journals (Sweden)

    Yin Min Theint

    2015-06-01

    Full Text Available Abstract This system proposes metal detector by using PIC microcontroller interfacing with PC. The system uses PIC microcontroller as the main controller whether the detected metal is ferrous metal or non-ferrous metal. Among various types of metal sensors and various types of metal detecting technologies concentric type induction coil sensor and VLF very low frequency metal detecting technology are used in this system. This system consists of two configurations Hardware configuration and Software configuration. The hardware components include induction coil sensors which senses the frequency changes of metal a PIC microcontroller personal computer PC buzzer light emitting diode LED and webcam. The software configuration includes a program controller interface. PIC MikroCprogramming language is used to implement the control system. This control system is based on the PIC 16F887 microcontroller.This system is mainly used in mining and high security places such as airport plaza shopping mall and governmental buildings.

  4. Metal contamination in water sediments; Contaminacion por metales en sedimentos acuaticos

    Energy Technology Data Exchange (ETDEWEB)

    Usero Garcia, J.; Morillo Aguado, J.; Gracia Manarillo, I. [Universidad de Sevilla. Sevilla (Spain)

    1997-09-01

    The origin, distribution, and behaviour of metals in aquatic systems, and factors affecting the solubilization and entry into the water column of metals associated with sediments are examined. Also, the interaction of these metals with and toxic effects on living organisms are studied. Finally, the existing methods for assessing the degree of pollution of sediments and the mobility of the metals associated with the sediments are explained. In the second section of this paper, the methods used for sampling, preparing, and analysing the sediments are described. (Author) 48 refs.

  5. Contamination and Spatial Variation of Heavy Metals in the Soil-Rice System in Nanxun County, Southeastern China

    Science.gov (United States)

    Zhao, Keli; Fu, Weijun; Ye, Zhengqian; Zhang, Chaosheng

    2015-01-01

    There is an increasing concern about heavy metal contamination in farmland in China and worldwide. In order to reveal the spatial features of heavy metals in the soil-rice system, soil and rice samples were collected from Nanxun, Southeastern China. Compared with the guideline values, elevated concentrations of heavy metals in soils were observed, while heavy metals in rice still remained at a safe level. Heavy metals in soils and rice had moderate to strong spatial dependence (nugget/sill ratios: 13.2% to 49.9%). The spatial distribution of copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) in soils illustrated that their high concentrations were located in the southeast part. The high concentrations of cadmium (Cd) in soils were observed in the northeast part. The accumulation of all the studied metals is related to the long-term application of agrochemicals and industrial activities. Heavy metals in rice showed different spatial distribution patterns. Cross-correlograms were produced to quantitatively determine the spatial correlation between soil properties and heavy metals composition in rice. The pH and soil organic matter had significant spatial correlations with the concentration of heavy metals in rice. Most of the selected variables had clear spatial correlation ranges for heavy metals in rice, which could be further applied to divide agricultural management zones. PMID:25635917

  6. Contamination and Spatial Variation of Heavy Metals in the Soil-Rice System in Nanxun County, Southeastern China

    Directory of Open Access Journals (Sweden)

    Keli Zhao

    2015-01-01

    Full Text Available There is an increasing concern about heavy metal contamination in farmland in China and worldwide. In order to reveal the spatial features of heavy metals in the soil-rice system, soil and rice samples were collected from Nanxun, Southeastern China. Compared with the guideline values, elevated concentrations of heavy metals in soils were observed, while heavy metals in rice still remained at a safe level. Heavy metals in soils and rice had moderate to strong spatial dependence (nugget/sill ratios: 13.2% to 49.9%. The spatial distribution of copper (Cu, nickel (Ni, lead (Pb and zinc (Zn in soils illustrated that their high concentrations were located in the southeast part. The high concentrations of cadmium (Cd in soils were observed in the northeast part. The accumulation of all the studied metals is related to the long-term application of agrochemicals and industrial activities. Heavy metals in rice showed different spatial distribution patterns. Cross-correlograms were produced to quantitatively determine the spatial correlation between soil properties and heavy metals composition in rice. The pH and soil organic matter had significant spatial correlations with the concentration of heavy metals in rice. Most of the selected variables had clear spatial correlation ranges for heavy metals in rice, which could be further applied to divide agricultural management zones.

  7. Contamination and spatial variation of heavy metals in the soil-rice system in Nanxun County, Southeastern China.

    Science.gov (United States)

    Zhao, Keli; Fu, Weijun; Ye, Zhengqian; Zhang, Chaosheng

    2015-01-28

    There is an increasing concern about heavy metal contamination in farmland in China and worldwide. In order to reveal the spatial features of heavy metals in the soil-rice system, soil and rice samples were collected from Nanxun, Southeastern China. Compared with the guideline values, elevated concentrations of heavy metals in soils were observed, while heavy metals in rice still remained at a safe level. Heavy metals in soils and rice had moderate to strong spatial dependence (nugget/sill ratios: 13.2% to 49.9%). The spatial distribution of copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) in soils illustrated that their high concentrations were located in the southeast part. The high concentrations of cadmium (Cd) in soils were observed in the northeast part. The accumulation of all the studied metals is related to the long-term application of agrochemicals and industrial activities. Heavy metals in rice showed different spatial distribution patterns. Cross-correlograms were produced to quantitatively determine the spatial correlation between soil properties and heavy metals composition in rice. The pH and soil organic matter had significant spatial correlations with the concentration of heavy metals in rice. Most of the selected variables had clear spatial correlation ranges for heavy metals in rice, which could be further applied to divide agricultural management zones.

  8. Removal of heavy metals from fly ash leachate using combined bioelectrochemical systems and electrolysis

    International Nuclear Information System (INIS)

    Tao, Hu-Chun; Lei, Tao; Shi, Gang; Sun, Xiao-Nan; Wei, Xue-Yan; Zhang, Li-Juan; Wu, Wei-Min

    2014-01-01

    Highlights: • Heavy metals removal from MSWI fly ash with BES and electrolysis was confirmed. • 98.5% of Cu(II), 95.4% of Zn(II) and 98.1% of Pb(II) removal were achieved in reactors. • BESs can remove some heavy metals in fly ash with energy saving. -- Abstract: Based on environmental and energetic analysis, a novel combined approach using bioelectrochemical systems (BES) followed by electrolysis reactors (ER) was tested for heavy metals removal from fly ash leachate, which contained high detectable levels of Zn, Pb and Cu according to X-ray diffraction analysis. Acetic acid was used as the fly ash leaching agent and tested under various leaching conditions. A favorable condition for the leaching process was identified to be liquid/solid ratio of 14:1 (w/w) and leaching duration 10 h at initial pH 1.0. It was confirmed that the removal of heavy metals from fly ash leachate with the combination of BESs and ER is feasible. The metal removal efficiency was achieved at 98.5%, 95.4% and 98.1% for Cu(II), Zn(II), and Pb(II), respectively. Results of scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) indicated that Cu(II) was reduced and recovered mainly as metal Cu on cathodes related to power production, while Zn(II) and Pb(II) were not spontaneously reduced in BESs without applied voltage and basically electrolyzed in the electrolysis reactors

  9. The electrodeposition and rare earths reduction in the molten salt actinides recovery systems using liquid metal

    International Nuclear Information System (INIS)

    Shim, J-B.; Lee, J-H.; Kwon, S-W.; Ahn, B-G.; Woo, M-S.; Lee, B-J.; Kim, E-H.; Park, H-S.; Yoo, J-H.

    2005-01-01

    A pyrochemical partitioning system uses liquid metals such as cadmium and bismuth in order to recover the actinide metals from a molten salt mixture containing rare earth fission product metals. The liquid metals play roles as a cathode in the electrowinning or an extracting phase in the reductive extraction operation. The product resulting from the above operations is metal-cadmium or-bismuth alloy, which should contain the rare earth element amounts as low as possible for a transmutation purpose. In this study, the electrodeposition behaviours of uranium and lanthanide elements such as La, Ce and Nd were investigated for solid molybdenum and liquid cadmium electrodes in a molten LiCl-KCl eutectic salt. Electrochemical methods used are a cyclic voltammetry (CV) and a chronopotentiometry for monitoring the salt phase and recovering the metals, respectively. The CV graphs for monitoring the oxidizing agent CdCl 2 in the salt phase were obtained. These show a time dependently disappearance of the oxidizing agent corresponding to the formation of UCl 3 by inserting the uranium metal into the salt. Also, a sequential oxidation technique which is added at a controlled amount of the oxidizing agents into the salt phase was applied. It was found that this method is feasible for the selective reduction of the rare earths content in liquid metal alloys. (author)

  10. Designing a logistic control system : dealing with changes in Fokker's sheet metal unit

    NARCIS (Netherlands)

    Gomes, Javier

    2008-01-01

    The following report presents the results of the Logistics Design Project carried out at the sheet metal unit of Stork-Fokker AESP, from October 2007 to March 2008. Stork Fokker AESP designs, develops and produces advanced structures and electrical systems for the aerospace and defense industry. The

  11. Multidrug-Resistance and Toxic Metal Tolerance of Medically Important Bacteria Isolated from an Aquaculture System

    Science.gov (United States)

    Resende, Juliana Alves; Silva, Vânia L.; Fontes, Cláudia Oliveira; Souza-Filho, Job Alves; de Oliveira, Tamara Lopes Rocha; Coelho, Cíntia Marques; César, Dionéia Evangelista; Diniz, Cláudio Galuppo

    2012-01-01

    The use of antimicrobials and toxic metals should be considered carefully in aquaculture and surrounding environments. We aimed to evaluate medically relevant bacteria in an aquaculture system and their susceptibility to antimicrobials and toxic metals. Selective cultures for enterobacteria (ENT), non-fermenting Gram-negative rods (NFR) and Gram-positive cocci (GPC) were obtained from water samples collected in two different year seasons. The isolated bacteria were biochemically identified and antimicrobial and toxic metal susceptibility patterns were determined. Overall, 407 representative strains were recovered. In general, bacteria isolated from fish ponds showed higher multiple antibiotic resistance indices when compared to those isolated from a water-fed canal. Resistance to penicillin and azithromycin was observed more frequently in the GPC group, whereas resistance to ampicillin and ampicillin/sulbactam or gentamicin was observed more frequently in the ENT and NFR groups, respectively. All the isolated bacteria were tolerant to nickel, zinc, chromium and copper at high levels (≥1,024 μg mL−1), whereas tolerance to cadmium and mercury varied among the isolated bacteria (2–1,024 μg mL−1). Multidrug-resistant bacteria were more frequent and diverse in fish ponds than in the water-fed canal. A positive correlation was observed between antimicrobial resistance and metal tolerance. The data point out the need for water treatment associated with the aquaculture system. PMID:22972388

  12. Metal Ion Concentrations in Body Fluids after Implantation of Hip Replacements with Metal-on-Metal Bearing – Systematic Review of Clinical and Epidemiological Studies

    Science.gov (United States)

    Hartmann, Albrecht; Hannemann, Franziska; Lützner, Jörg; Seidler, Andreas; Drexler, Hans; Günther, Klaus-Peter; Schmitt, Jochen

    2013-01-01

    Introduction The use of metal-on-metal (MoM) total hip arthroplasty (THA) increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds) in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. Objective To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. Methods Systematic review of clinical trials (RCTs) and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum) in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor), patient characteristics as well as study quality characteristics (secondary explanatory factors). Results Overall, 104 studies (11 RCTs, 93 epidemiological studies) totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine) irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L). Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. Discussion Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed „time out“ for stemmed large-head MoM-THA and recommend a restricted indication for hip

  13. Hydrogen Storage using Metal Hydrides in a Stationary Cogeneration System

    International Nuclear Information System (INIS)

    Botzung, Maxime; Chaudourne, Serge; Perret, Christian; Latroche, Michel; Percheron-Guegan, Annick; Marty Philippe

    2006-01-01

    In the frame of the development of a hydrogen production and storage unit to supply a 40 kW stationary fuel cell, a metal hydride storage tank was chosen according to its reliability and high energetic efficiency. The study of AB5 compounds led to the development of a composition adapted to the project needs. The absorption/desorption pressures of the hydride at 75 C (2 / 1.85 bar) are the most adapted to the specifications. The reversible storage capacity (0.95 %wt) has been optimized to our work conditions and chemical kinetics is fast. The design of the Combined Heat and Power CHP system requires 5 kg hydrogen storage but in a first phase, only a 0.1 kg prototype has been realised and tested. Rectangular design has been chosen to obtain good compactness with an integrated plate fin type heat exchanger designed to reach high absorption/desorption rates. In this paper, heat and mass transfer characteristics of the Metal Hydride tank (MH tank) during absorption/desorption cycles are given. (authors)

  14. Dissolution of metallic uranium and its alloys. Part 1. Review of analytical and process-scale metallic uranium dissolution

    International Nuclear Information System (INIS)

    Laue, C.A.; Gates-Anderson, D.; Fitch, T.E.

    2004-01-01

    This review focuses on dissolution/reaction systems capable of treating uranium metal waste to remove its pyrophoric properties. The primary emphasis is the review of literature describing analytical and production-scale dissolution methods applied to either uranium metal or uranium alloys. A brief summary of uranium's corrosion behavior is included since the corrosion resistance of metals and alloys affects their dissolution behavior. Based on this review, dissolution systems were recommended for subsequent screening studies designed to identify the best system to treat depleted uranium metal wastes at Lawrence Livermore National Laboratory (LLNL). (author)

  15. A self-adjustable four-point probing system using polymeric three dimensional coils and non-toxic liquid metal

    Energy Technology Data Exchange (ETDEWEB)

    Oyunbaatar, Nomin-Erdene; Choi, Young Soo; Lee, Dong-Weon, E-mail: mems@jnu.ac.kr [MEMS and Nanotechnology Laboratory, School of Mechanical Engineering, Chonnam National University, Gwangju 500757 (Korea, Republic of)

    2015-12-15

    This paper describes a self-adjustable four-point probe (S4PP) system with a square configuration. The S4PP system consists of 3D polymer coil springs for the independent operation of each tungsten (W) probe, microfluidic channels filled with a nontoxic liquid metal, and a LabView-based control system. The 3D coil springs made by PMMA are fabricated with a 3D printer and are positioned in a small container filled with the non-toxic liquid metal. This unique configuration allows independent self-adjustment of the probe heights for precise measurements of the electrical properties of both flexible and large-step-height microsamples. The feasibility of the fabricated S4PP system is evaluated by measuring the specific resistance of Cr and Au thin films deposited on silicon wafers. The system is then employed to evaluate the electrical properties of a Au thin film deposited onto a flexible and easily breakable silicon diaphragm (spring constant: ∼3.6 × 10{sup −5} N/m). The resistance of the Cr thin films (thickness: 450 nm) with step heights of 60 and 90 μm is also successfully characterized. These experimental results indicate that the proposed S4PP system can be applied to common metals and semiconductors as well as flexible and large-step-height samples.

  16. A self-adjustable four-point probing system using polymeric three dimensional coils and non-toxic liquid metal

    International Nuclear Information System (INIS)

    Oyunbaatar, Nomin-Erdene; Choi, Young Soo; Lee, Dong-Weon

    2015-01-01

    This paper describes a self-adjustable four-point probe (S4PP) system with a square configuration. The S4PP system consists of 3D polymer coil springs for the independent operation of each tungsten (W) probe, microfluidic channels filled with a nontoxic liquid metal, and a LabView-based control system. The 3D coil springs made by PMMA are fabricated with a 3D printer and are positioned in a small container filled with the non-toxic liquid metal. This unique configuration allows independent self-adjustment of the probe heights for precise measurements of the electrical properties of both flexible and large-step-height microsamples. The feasibility of the fabricated S4PP system is evaluated by measuring the specific resistance of Cr and Au thin films deposited on silicon wafers. The system is then employed to evaluate the electrical properties of a Au thin film deposited onto a flexible and easily breakable silicon diaphragm (spring constant: ∼3.6 × 10"−"5 N/m). The resistance of the Cr thin films (thickness: 450 nm) with step heights of 60 and 90 μm is also successfully characterized. These experimental results indicate that the proposed S4PP system can be applied to common metals and semiconductors as well as flexible and large-step-height samples.

  17. Chemistry of the metal-polymer interfacial region.

    Science.gov (United States)

    Leidheiser, H; Deck, P D

    1988-09-02

    In many polymer-metal systems, chemical bonds are formed that involve metal-oxygen-carbon complexes. Infrared and Mössbauer spectroscopic studies indicate that carboxylate groups play an important role in some systems. The oxygen sources may be the polymer, the oxygen present in the oxide on the metal surface, or atmospheric oxygen. Diffusion of metal ions from the substrate into the polymer interphase may occur in some systems that are cured at elevated temperatures. It is unclear whether a similar, less extensive diffusion occurs over long time periods in systems maintained at room temperature. The interfacial region is dynamic, and chemical changes occur with aging at room temperature. Positron annihilation spectroscopy may have application to characterizing the voids at the metal-polymer interface.

  18. Systems analysis of a 100-MWe modular liquid metal cooled reactor

    International Nuclear Information System (INIS)

    Morris, E.E.; Rhow, S.K.; Switick, D.M.

    1985-01-01

    The response of a 100-MWe modular liquid metal cooled reactor to unprotected loss of flow and/or loss of primary heat removal accidents is analyzed using the systems analysis code SASSYS. The reactor response is tracked for the first 1000 s following a postulated upset in the primary heat removal system. The calculations do not take credit for the functioning of any decay heat removal other than through the secondary system. In addition to the power rating, other features of the reactor are an average sodium temperature rise of 148 K, a sodium void worth (counting the core and upper axial blanket) of 1.89 $, and 3.6 $ of Doppler feedback due to a uniform e-fold fuel temperature increase

  19. Trial fabrication and preliminary characterization of electrical insulator for liquid metal system

    International Nuclear Information System (INIS)

    Nakamichi, Masaru; Kawamura, Hiroshi; Oyamada, Rokuro

    1995-03-01

    In the design of the liquid metal blanket, MHD pressure drop is one of critical issues. Ceramic coating on the surface of structural material is considered as an electrical insulator to reduce the MHD pressure drop. Ceramic coating such as Y 2 O 3 is a promising electrical insulator due to its high electrical resistivity and good compatibility with liquid lithium. This report describes the trial fabrication and preliminary characterization of electrical insulator for a design study of the liquid metal system. From the results of trial fabrication and preliminary characterization, it is concluded that densified atmospheric plasma spray Y 2 O 3 coating with 410SS undercoating between 316SS substrate and Y 2 O 3 coating is suitable for Y 2 O 3 coating fabrication. (author)

  20. Emergency cooling system for a liquid metal cooled reactor

    International Nuclear Information System (INIS)

    Murata, Ryoichi; Fujiwara, Toshikatsu.

    1980-01-01

    Purpose: To suitably cool liquid metal as coolant in emergency in a liquid metal cooled reactor by providing a detector for the pressure loss of the liquid metal passing through a cooling device in a loop in which the liquid metal is flowed and communicating the detector with a coolant flow regulator. Constitution: A nuclear reactor is stopped in nuclear reaction by control element or the like in emergency. If decay heat is continuously generated for a while and secondary coolant is insufficiently cooled with water or steam flowed through a steam and water loop, a cooler is started. That is, low temperature air is supplied by a blower through an inlet damper to the cooler to cool the secondary coolant flowed into the cooler through a bypass pipe so as to finally safely stop an entire plant. Since the liquid metal is altered in its physical properties by the temperature at this time, it is detected to regulate the opening of the valve of the damper according to the detected value. (Sekiya, K.)

  1. Tunneling Conductance in Two-Dimensional Junctions between a Normal Metal and a Ferromagnetic Rashba Metal

    Science.gov (United States)

    Oshima, Daisuke; Taguchi, Katsuhisa; Tanaka, Yukio

    2018-03-01

    We have studied charge transport in a ferromagnetic Rashba metal (FRM), where both Rashba type spin-orbit coupling (RSOC) and exchange coupling coexist. It has nontrivial metallic states, i.e., a normal Rashba metal (NRM), anomalous Rashba metal (ARM), and Rashba ring metal (RRM), and they are manipulated by tuning the Fermi level with an applied gate voltage. We theoretically studied the tunneling conductance (G) in a normal metal/FRM junction by changing the Fermi level via an applied gate voltage (Vg) on the FRM. We found a wide variation in the Vg dependence of G, which depends on the metallic states. In an NRM, the Vg dependence of G is the same as that in a conventional two-dimensional system. However, in an ARM, the Vg dependence of G is similar to that in a conventional one- (two-)dimensional system for a large (small) RSOC. Furthermore, in an RRM, which is generated by a large RSOC, the Vg dependence of G is similar to that in the one-dimensional system. In addition, these anomalous properties stem from the density of states in the ARM and RRM caused by the large RSOC and exchange coupling rather than the spin-momentum locking of RSOC.

  2. A METALLICITY-SPIN TEMPERATURE RELATION IN DAMPED Lyα SYSTEMS

    International Nuclear Information System (INIS)

    Kanekar, Nissim; Smette, Alain; Briggs, Frank H.; Chengalur, Jayaram N.

    2009-01-01

    We report evidence for an anti-correlation between spin temperature T s and metallicity [Z/H], detected at 3.6σ significance in a sample of 26 damped Lyα absorbers (DLAs) at redshifts 0.09 s = (-0.68 ± 0.17) x [Z/H] + (2.13 ± 0.21) from a linear regression analysis. Our results indicate that the high T s values found in DLAs do not arise from differences between the optical and radio sightlines, but are likely to reflect the underlying gas temperature distribution. The trend between T s and [Z/H] can be explained by the larger number of radiation pathways for gas cooling in galaxies with high metal abundances, resulting in a high cold gas fraction, and hence, a low spin temperature. Conversely, low-metallicity galaxies have fewer cooling routes, yielding a larger warm gas fraction and a high T s . Most DLAs at z > 1.7 have low metallicities, [Z/H] s and [Z/H] is consistent with the presence of a mass-metallicity relation in DLAs, suggested by the tight correlation between DLA metallicity and the kinematic widths of metal lines. Most high-z DLAs are likely to arise in galaxies with low masses (M vir 10.5 M sun ), low metallicities ([Z/H] <-1), and low cold gas fractions.

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

    Energy Technology Data Exchange (ETDEWEB)

    Judkins, R.R.; Tortorelli, P.F.; Judkins, R.R.; DeVan, J.H.; Wright, I.G. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1995-11-01

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

  4. Metal ion transporters and homeostasis.

    OpenAIRE

    Nelson, N

    1999-01-01

    Transition metals are essential for many metabolic processes and their homeostasis is crucial for life. Aberrations in the cellular metal ion concentrations may lead to cell death and severe diseases. Metal ion transporters play a major role in maintaining the correct concentrations of the various metal ions in the different cellular compartments. Recent studies of yeast mutants revealed key elements in metal ion homeostasis, including novel transport systems. Several of the proteins discover...

  5. Soil heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Sherameti, Irena [Jena Univ. (Germany). Inst. fuer Allgemeine Botanik und Pflanzenphysiologie; Varma, Ajit (eds.) [Amity Univ., Uttar Pradesh (India). Amity Inst. of Microbial Technology; Amity Science, Technology and Innovation Foundation, Noida, UP (India)

    2010-07-01

    Human activities have dramatically changed the composition and organisation of soils. Industrial and urban wastes, agricultural application and also mining activities resulted in an increased concentration of heavy metals in soils. How plants and soil microorganisms cope with this situation and the sophisticated techniques developed for survival in contaminated soils is discussed in this volume. The topics presented include: the general role of heavy metals in biological soil systems; the relation of inorganic and organic pollutions; heavy metal, salt tolerance and combined effects with salinity; effects on abuscular mycorrhizal and on saprophytic soil fungi; heavy metal resistance by streptomycetes; trace element determination of environmental samples; the use of microbiological communities as indicators; phytostabilization of lead polluted sites by native plants; effects of soil earthworms on removal of heavy metals and the remediation of heavy metal contaminated tropical land. (orig.)

  6. FLIT: Flowing LIquid metal Torus

    Science.gov (United States)

    Kolemen, Egemen; Majeski, Richard; Maingi, Rajesh; Hvasta, Michael

    2017-10-01

    The design and construction of FLIT, Flowing LIquid Torus, at PPPL is presented. FLIT focuses on a liquid metal divertor system suitable for implementation and testing in present-day fusion systems, such as NSTX-U. It is designed as a proof-of-concept fast-flowing liquid metal divertor that can handle heat flux of 10 MW/m2 without an additional cooling system. The 72 cm wide by 107 cm tall torus system consisting of 12 rectangular coils that give 1 Tesla magnetic field in the center and it can operate for greater than 10 seconds at this field. Initially, 30 gallons Galinstan (Ga-In-Sn) will be recirculated using 6 jxB pumps and flow velocities of up to 10 m/s will be achieved on the fully annular divertor plate. FLIT is designed as a flexible machine that will allow experimental testing of various liquid metal injection techniques, study of flow instabilities, and their control in order to prove the feasibility of liquid metal divertor concept for fusion reactors. FLIT: Flowing LIquid metal Torus. This work is supported by the US DOE Contract No. DE-AC02-09CH11466.

  7. Health risk assessment of heavy metals in soil-plant system amended with biogas slurry in Taihu basin, China.

    Science.gov (United States)

    Bian, Bo; Lin, Cheng; Lv, Lin

    2016-09-01

    Biogas slurry is a product of anaerobic digestion of manure that has been widely used as a soil fertilizer. Although the use for soil fertilizer is a cost-effective solution, it has been found that repeated use of biogas slurry that contains high heavy metal contents can cause pollution to the soil-plant system and risk to human health. The objective of this study was to investigate effects of biogas slurry on the soil-plant system and the human health. We analyzed the heavy metal concentrations (including As, Pb, Cu, Zn, Cr and Cd) in 106 soil samples and 58 plant samples in a farmland amended with biogas slurry in Taihu basin, China. Based on the test results, we assessed the potential human health risk when biogas slurry containing heavy metals was used as a soil fertilizer. The test results indicated that the Cd and Pb concentrations in soils exceeded the contamination limits and Cd exhibited the highest soil-to-root migration potential. Among the 11 plants analyzed, Kalimeris indica had the highest heavy metal absorption capacity. The leafy vegetables showed higher uptake of heavy metals than non-leafy vegetables. The non-carcinogenic risks mainly resulted from As, Pb, Cd, Cu and Zn through plant ingestion exposure. The integrated carcinogenic risks were associated with Cr, As and Cd in which Cr showed the highest risk while Cd showed the lowest risk. Among all the heavy metals analyzed, As and Cd appeared to have a lifetime health threat, which thus should be attenuated during production of biogas slurry to mitigate the heavy metal contamination.

  8. Metals and Neurodegeneration

    Science.gov (United States)

    Chen, Pan; Miah, Mahfuzur Rahman; Aschner, Michael

    2016-01-01

    Metals play important roles in the human body, maintaining cell structure and regulating gene expression, neurotransmission, and antioxidant response, to name a few. However, excessive metal accumulation in the nervous system may be toxic, inducing oxidative stress, disrupting mitochondrial function, and impairing the activity of numerous enzymes. Damage caused by metal accumulation may result in permanent injuries, including severe neurological disorders. Epidemiological and clinical studies have shown a strong correlation between aberrant metal exposure and a number of neurological diseases, including Alzheimer’s disease, amyotrophic lateral sclerosis, autism spectrum disorders, Guillain–Barré disease, Gulf War syndrome, Huntington’s disease, multiple sclerosis, Parkinson’s disease, and Wilson’s disease. Here, we briefly survey the literature relating to the role of metals in neurodegeneration. PMID:27006759

  9. Removal of Pb(II), Cu(II) and Cd(II) from aqueous solution by some fungi and natural adsorbents in single and multiple metal systems

    International Nuclear Information System (INIS)

    Shoaib, A.; Badar, T.; Aslam, N.

    2011-01-01

    Six fungal and 10 natural biosorbents were analyzed for their Cu(II), Cd(II) and Pb(II) uptake capacity from single, binary and ternary metal ion system. Preliminary screening biosorption of assays revealed 2 fungi (Aspergillus niger and Cunninghamella echinulata) and three natural [Cicer arietinum husk, Moringa oleifera flower and soil (clay)] adsorbents hold considerable high adsorption efficiency and capacity for 3 meta l ions amongst the adsorbents. Further biosorption trials with five elected adsorbents showed a considerable reduction in metal uptake capability of adsorbents in binary- and ternary systems as compared to singly metal system. Cd(II) manifested the highest inhibitory effect on the biosorption of other metal ions, followed by Pb(II) and Cu(II). On account of metal preference, the selectivity order for metal ion towards the studied biomass matrices was Pb(II) (40-90%) > Cd(II) (2-53%) > Cu(II) (2-30%). (author)

  10. Cutaneous and systemic hypersensitivity reactions to metallic implants

    DEFF Research Database (Denmark)

    Basko-Plluska, Juliana L; Thyssen, Jacob P; Schalock, Peter C

    2011-01-01

    ) following the insertion of intravascular stents, dental implants, cardiac pacemakers, or implanted gynecologic devices. Despite repeated attempts by researchers and clinicians to further understand this difficult area of medicine, the association between metal sensitivity and cutaneous allergic reactions......Cutaneous reactions to metal implants, orthopedic or otherwise, are well documented in the literature. The first case of a dermatitis reaction over a stainless steel fracture plate was described in 1966. Most skin reactions are eczematous and allergic in nature, although urticarial, bullous......, and vasculitic eruptions may occur. Also, more complex immune reactions may develop around the implants, resulting in pain, inflammation, and loosening. Nickel, cobalt, and chromium are the three most common metals that elicit both cutaneous and extracutaneous allergic reactions from chronic internal exposure...

  11. Metallic materials for medical use

    OpenAIRE

    Illarionov Anatoly; Belikov Sergey; Grib Stella; Yurovskikh Artem

    2017-01-01

    This article provides a brief overview of the metallic materials used as implants in orthopedics, the alloying system and a complex of the physical-mechanical properties for metallic materials certified for medical use, as well as the advantages and drawbacks of using metallic materials as implants. Approaches to improve the quality of an implant made of metallic materials are noted.

  12. Non-metallic structural wrap systems for pipe

    International Nuclear Information System (INIS)

    Walker, R.H.; Wesley Rowley, C.

    2001-01-01

    The use of thermoplastics and reinforcing fiber has been a long-term application of non-metallic material for structural applications. With the advent of specialized epoxies and carbon reinforcing fiber, structural strength approaching and surpassing steel has been used in a wide variety of applications, including nuclear power plants. One of those applications is a NSWS for pipe and other structural members. The NSWS is system of integrating epoxies with reinforcing fiber in a wrapped geometrical configuration. This paper specifically addresses the repair of degraded pipe in heat removal systems used in nuclear power plants, which is typically caused by corrosion, erosion, or abrasion. Loss of structural material leads to leaks, which can be arrested by a NSWS for the pipe. The technical aspects of using thermoplastics to structurally improve degraded pipe in nuclear power plants has been addressed in the ASME B and PV Code Case N-589. Using the fundamentals described in that Code Case, this paper shows how this technology can be extended to pipe repair from the outside. This NSWS has already been used extensively in non-nuclear applications and in one nuclear application. The cost to apply this NSWS is typically substantially less than replacing the pipe and may be technically superior to replacing the pipe. (author)

  13. Gases and carbon in metals. Pt. 14

    International Nuclear Information System (INIS)

    Jehn, H.; Speck, H.; Hehn, W.; Fromm, E.; Hoerz, G.

    1981-01-01

    This issue is part of a series of data on 'Gases and Carbon in Metals' which supplements the data compilation in the book 'Gase und Kohlenstoff in Metallen' (Gases and Carbon in Metals), edited by E. Fromm and E. Gebhardt, Springer-Verlag, Berlin 1976. The present survey includes results from papers published after the copy deadline and recommends critically selected data. Furthermore, it comprises a bibliography of relevant literature. For each element, firstly data on binary systems are presented, starting with hydrogen and followed by carbon, nitrogen, oxygen, and rare gases. Within one metal-metalloid system the data are listed under topics such as solubility, solubility limit, dissociation pressure of compounds, vapour pressure of volatile oxides, thermodynamic data, diffusion, transport parameters (effective valence, heat of transport), permeation of gases through metals, gas absorption and gas desorption kinetics, compound formation kinetics, precipitation kinetics, and property changes. Following the data on binary systems, the data of ternary systems are presented, beginning with systems which contain one metal and two gases or one gas and carbon and continuing with systems with two metals and one gas or carbon. (orig./GE)

  14. Screening of willow species for resistance to heavy metals: comparison of performance in a hydroponics system and field trials.

    Science.gov (United States)

    Watson, C; Pulford, I D; Riddell-Black, D

    2003-01-01

    The aim of this study was to ascertain whether metal resistance in willow (Salix) clones grown in a hydroponics screening test correlated with data from the same clones grown independently in a field trial. If so, results from a short-term, glasshouse-based system could be extrapolated to the field, allowing rapid identification of willows suitable for planting in metal-contaminated substrates without necessitating longterm field trials. Principal Components Analysis was used to show groups of clones and to assess the relative importance of the parameters measured in both the hydroponics system and the field; including plant response factors such as increase in stem height, as well as metal concentrations in plant tissues. The clones tested fell into two distinct groups. Salix viminalis clones and the basket willow Black Maul (S. triandra) were less resistant to elevated concentrations of heavy metals than a group of hardier clones, including S. burjatica 'Germany,' S.x dasyclados, S. candida and S. spaethii. The more resistant clones produced more biomass in the glasshouse and field, and had higher metal concentrations in the wood. The less resistant clones had greater concentrations of Cu and Ni in the bark, and produced less biomass in the glasshouse and field. Significant relationships were found between the response of the same clones grown the in short-term glasshouse hydroponics system and in the field.

  15. Metal X-ray microanalysis in the olfactory system of rainbow trout exposed to low level of copper

    International Nuclear Information System (INIS)

    Julliard, A.K.; Astic, L.; Saucier, D.

    1995-01-01

    It has recently been shown that a chronic copper exposure induces specific degeneration of olfactory receptor cells in rainbow trout; however, the exact mechanism of action of the metal is not yet known. Using X-ray microanalysis in transmission electron microscopy, we have studied the distribution of metal in the olfactory system of fish exposed for 15,30 and 60 days to 20 μg/l of copper. This was done in order to determine if it was accumulated in receptor cells and transported into the central nervous system via the olfactory nerve. No copper accumulation was detected either in the olfactory epithelium, in the olfactory nerve or in the olfactory bulb. The heavy metal was exclusively found within melanosomes of melanophores located in the lamina propria. After 60 days of exposure, the copper content in melanosomes was about two-fold higher than that in controls. As far as some morphological recovery took place in the olfactory organ during the metal exposure, which lets us suppose that some detoxication mechanism occurs, it could be suggested that metanophores might be somehow involved in such a mechanism. (authors). 57 refs., 15 figs

  16. Organophosphorus flame retardants and heavy metals in municipal landfill leachate treatment system in Guangzhou, China.

    Science.gov (United States)

    Deng, Mingjun; Kuo, Dave T F; Wu, Qihang; Zhang, Ying; Liu, Xinyu; Liu, Shengyu; Hu, Xiaodong; Mai, Bixian; Liu, Zhineng; Zhang, Haozhi

    2018-05-01

    The occurrence, distribution and removal efficiencies of organophosphorus flame retardants (OPFRs) and metals were examined in a municipal landfill leachate treatment system in Guangzhou, China. Five OPFRs and thirty-five metals were detected in wastewater samples collected at different treatment stages. ∑OPFRs was reduced from 4807.02 ng L -1 to 103.91 ng L -1 through the treatment system, with close to 98% removed from the dissolved phase. Tris(clorisopropyl) phosphates (TCPPs) dominated through the treatment process and accounted for over 80% and 50% of ∑OPFRs at the influent and the effluent, respectively. TCPPs were most efficiently removed (98.6%) followed by tris(2-chloroethyl) phosphate (TCEP) (96.6%) and triphenyl phosphate (TPP) (88.5%). For metals, Fe, Cr, and Rb were dominant in the raw leachate, detected at 7.55, 2.82, and 4.50 mg L -1 , respectively. Thirteen regulated heavy metals - including eight major pollutants (i.e., As. Cd, Cr, Cu, Hg, Ni, Pb, and Zn) - have been detected in all wastewater samples at sub-mg L -1 levels. Over 99.5% removal was achieved for Cr, Ni, and Fe, and close to 95% removal efficiency was observed for Rb. For the eight major heavy metals, over 99% removal was observed; the only exception was Cu, which was removed at 89%. It was found that microfiltration/reverse osmosis was critical for the removal of OPFRs and heavy metals while the core biological treatment played a minor role towards their removal. Remobilization of Co, Cu, Fe, Hg, Mn, Ni, Sb, and Sr from the returned sludge occurred during the second denitrification, indicating the need for additional post-biological process for effective removal of both contaminants. This study highlights the critical need to develop cheap, effective treatment technologies for contaminants-laden leachate generated from open dumps and under-designed landfills. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Gene expression influences on metal immunomodulation

    International Nuclear Information System (INIS)

    Lynes, Michael A.; Fontenot, Andrew P.; Lawrence, David A.; Rosenspire, Allen J.; Pollard, K. Michael

    2006-01-01

    Heavy metals in the environment originate from both human activities and natural processes. Exposure to these metals can result in important changes to immune activity. Depending on the metal and dose, these changes can result in enhanced immune function, diminished immune responses, or altered responses that produce autoimmune disease. One of the intriguing aspects of these various phenomena are the multiple points of interaction with cellular machinery at which metals elicit these changes. The individual sections of this review serve to underscore the variety of targets that can be altered by exposure to heavy metals, and provide some comparisons between the effects of specific heavy metals on the immune system. These observations may ultimately lead us to a comprehensive understanding of the mechanisms by which metals alter the immune system, and may enable the development of countermeasures to offset these effects

  18. Heavy metal transport in large river systems: heavy metal emissions and loads in the Rhine and Elbe river basins

    Science.gov (United States)

    Vink, Rona; Behrendt, Horst

    2002-11-01

    Pollutant transport and management in the Rhine and Elbe basins is still of international concern, since certain target levels set by the international committees for protection of both rivers have not been reached. The analysis of the chain of emissions of point and diffuse sources to river loads will provide policy makers with a tool for effective management of river basins. The analysis of large river basins such as the Elbe and Rhine requires information on the spatial and temporal characteristics of both emissions and physical information of the entire river basin. In this paper, an analysis has been made of heavy metal emissions from various point and diffuse sources in the Rhine and Elbe drainage areas. Different point and diffuse pathways are considered in the model, such as inputs from industry, wastewater treatment plants, urban areas, erosion, groundwater, atmospheric deposition, tile drainage, and runoff. In most cases the measured heavy metal loads at monitoring stations are lower than the sum of the heavy metal emissions. This behaviour in large river systems can largely be explained by retention processes (e.g. sedimentation) and is dependent on the specific runoff of a catchment. Independent of the method used to estimate emissions, the source apportionment analysis of observed loads was used to determine the share of point and diffuse sources in the heavy metal load at a monitoring station by establishing a discharge dependency. The results from both the emission analysis and the source apportionment analysis of observed loads were compared and gave similar results. Between 51% (for Hg) and 74% (for Pb) of the total transport in the Elbe basin is supplied by inputs from diffuse sources. In the Rhine basin diffuse source inputs dominate the total transport and deliver more than 70% of the total transport. The diffuse hydrological pathways with the highest share are erosion and urban areas.

  19. Mass fractionation processes of transition metal isotopes

    Science.gov (United States)

    Zhu, X. K.; Guo, Y.; Williams, R. J. P.; O'Nions, R. K.; Matthews, A.; Belshaw, N. S.; Canters, G. W.; de Waal, E. C.; Weser, U.; Burgess, B. K.; Salvato, B.

    2002-06-01

    Recent advances in mass spectrometry make it possible to utilise isotope variations of transition metals to address some important issues in solar system and biological sciences. Realisation of the potential offered by these new isotope systems however requires an adequate understanding of the factors controlling their isotope fractionation. Here we show the results of a broadly based study on copper and iron isotope fractionation during various inorganic and biological processes. These results demonstrate that: (1) naturally occurring inorganic processes can fractionate Fe isotope to a detectable level even at temperature ˜1000°C, which challenges the previous view that Fe isotope variations in natural system are unique biosignatures; (2) multiple-step equilibrium processes at low temperatures may cause large mass fractionation of transition metal isotopes even when the fractionation per single step is small; (3) oxidation-reduction is an importation controlling factor of isotope fractionation of transition metal elements with multiple valences, which opens a wide range of applications of these new isotope systems, ranging from metal-silicate fractionation in the solar system to uptake pathways of these elements in biological systems; (4) organisms incorporate lighter isotopes of transition metals preferentially, and transition metal isotope fractionation occurs stepwise along their pathways within biological systems during their uptake.

  20. Tritium in metals

    International Nuclear Information System (INIS)

    Schober, T.

    1990-01-01

    In this Chapter a review is given of some of the important features of metal tritides as opposed to hydrides and deuterides. After an introduction to the topics of tritium and tritium in metals information will be presented on a variety of metal-tritium systems. Of main interest here are the differences from the classic hydrogen behavior; the so called isotope effect. A second important topic is that of aging effects produced by the accumulation of 3 He in the samples. (orig.)

  1. Metallic Biosorption Using Yeasts in Continuous Systems

    Directory of Open Access Journals (Sweden)

    Karla Miriam Hernández Mata

    2013-01-01

    Full Text Available Mining effluents were found to be the main source of pollution by heavy metals of the surface water in the San Pedro River in Sonora, Mexico. The overall objective of this study was to determine the biosorption of Zn, Cu, Mn, and Fe with yeasts isolated from San Pedro River in a continuous system. The tests conducted in two reactors packed with zeolite connected in series. The first reactor was inoculated mixing two yeasts species, and the effluent of the first reactor was fed to second reactor. Subsequently, the first reactor was fed with contaminated water of San Pedro River and effluent from this was the second reactor influent. After 40 days of the experiment a reduction of 81.5% zinc, 76.5% copper, manganese 95.5%, and 99.8% of iron was obtained. These results show that the selected yeasts are capable of biosorbing zinc, copper, manganese, and iron under these conditions.

  2. Purification of uranium metal

    International Nuclear Information System (INIS)

    Suzuki, Kenji; Shikama, Tatsuo; Ochiai, Akira.

    1993-01-01

    We developed the system for purifying uranium metal and its metallic compounds and for growing highly pure uranium compounds to study their intrinsic physical properties. Uranium metal was zone refined under low contamination conditions as far as possible. The degree of the purity of uranium metal was examined by the conventional electrical resistivity measurement and by the chemical analysis using the inductive coupled plasma emission spectrometry (ICP). The results show that some metallic impurities evaporated by the r.f. heating and other usual metallic impurities moved to the end of a rod with a molten zone. Therefore, we conclude that the zone refining technique is much effective to the removal of metallic impurities and we obtained high purified uranium metal of 99.99% up with regarding to metallic impurities. The maximum residual resistivity ratio, the r.r.r., so far obtained was about 17-20. Using the purified uranium, we are attempting to grow a highly pure uranium-titanium single crystals. (author)

  3. Quantum criticality around metal-insulator transitions of strongly correlated electron systems

    Science.gov (United States)

    Misawa, Takahiro; Imada, Masatoshi

    2007-03-01

    Quantum criticality of metal-insulator transitions in correlated electron systems is shown to belong to an unconventional universality class with violation of the Ginzburg-Landau-Wilson (GLW) scheme formulated for symmetry breaking transitions. This unconventionality arises from an emergent character of the quantum critical point, which appears at the marginal point between the Ising-type symmetry breaking at nonzero temperatures and the topological transition of the Fermi surface at zero temperature. We show that Hartree-Fock approximations of an extended Hubbard model on square lattices are capable of such metal-insulator transitions with unusual criticality under a preexisting symmetry breaking. The obtained universality is consistent with the scaling theory formulated for Mott transitions and with a number of numerical results beyond the mean-field level, implying that preexisting symmetry breaking is not necessarily required for the emergence of this unconventional universality. Examinations of fluctuation effects indicate that the obtained critical exponents remain essentially exact beyond the mean-field level. It further clarifies the whole structure of singularities by a unified treatment of the bandwidth-control and filling-control transitions. Detailed analyses of the criticality, containing diverging carrier density fluctuations around the marginal quantum critical point, are presented from microscopic calculations and reveal the nature as quantum critical “opalescence.” The mechanism of emerging marginal quantum critical point is ascribed to a positive feedback and interplay between the preexisting gap formation present even in metals and kinetic energy gain (loss) of the metallic carrier. Analyses of crossovers between GLW type at nonzero temperature and topological type at zero temperature show that the critical exponents observed in (V,Cr)2O3 and κ-ET -type organic conductors provide us with evidence for the existence of the present marginal

  4. Making Sense of Metal Allergy and Hypersensitivity to Metallic Implants in Relation to Hand Surgery.

    Science.gov (United States)

    Christensen, Thomas J; Samant, Shefali A; Shin, Alexander Y

    2017-09-01

    All metals implanted into a biological system undergo some degree of corrosion depending upon its composition. The electrochemical process of corrosion produces free metal ions, which may activate the host's immune system through a variety of mechanisms. Whereas dermal metal hypersensitivity is common, affecting 10% to 15% of the population, the immune reaction from implanted metals is much less common (allergy and hypersensitivity producing a multitude of patient symptoms. Superficial symptoms may be mild to severe forms of dermatitis, urticaria, pruritus, and vasculitis, whereas deep sequelae include metallosis-related pseudotumor, implant loosening, and joint stiffness. Currently, there are clinical tests to evaluate patients for metal hypersensitivity, but there is little agreement regarding the ideal timing and clinical situation prompting the work-up of a patient for a metal allergy or hypersensitivity. An understanding of the epidemiology, etiology, basic science, diagnostic testing, and treatment of patients with suspected metal allergy, as it pertains to the current literature, will aid orthopedic and plastic surgeons of all subspecialties in the management of patients requiring metallic implants. Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  5. High-purity metal-carbon eutectic systems as thermometric fixed points in the range from 1000 K to 3500 K; Des systemes eutectiques metal-carbone de grande purete comme points fixes de temperature dans l'intervalle 1000-3500 K

    Energy Technology Data Exchange (ETDEWEB)

    Bloembergen, P.; Yamada, Y.; Sasajima, N.; Yamamoto, N. [National Metrology Institute of Japan (NMIJ), AIST, Tsukuba (Japan); Torizuka, S.; Yoshida, N. [National Institute for Materials Science (NIMS), Tsukuba (Japan)

    2004-12-01

    A survey will be given of metal-carbon (M-C) and metal carbide-carbon (MC-C) systems presently in development for applications in thermometry in the range from 1000 K to about 3500 K. The advantages of these systems as fixed points at high temperatures as compared to systems relying on pure metals will be elucidated. Purification of the components making up the M-C or MC-C systems is a prerequisite to their implementation as reference fixed points in thermometry, requiring a high level of reproducibility of the eutectic temperature. To set an example a study on the effect of impurities on the eutectic transition of Fe-C is included in the survey. Experimentally obtained melting curves are compared with the curves calculated on the basis of a thermodynamic model, which includes the impurities in question as components. The calculations of the melting curves are based upon: (1) the Equilibrium solidification model and (2) the Scheil-Gulliver solidification model, which handle the effects of the impurities on the transition process in such a way that they may be assumed to set lower and upper boundaries to the associated melting ranges, respectively. We will conclude pointing out fields of common interest to materials science and thermometry within the realm of ultra-pure materials. (authors)

  6. Metal Contacts to Gallium Arsenide.

    Science.gov (United States)

    Ren, Fan

    1991-07-01

    While various high performance devices fabricated from the gallium arsenide (GaAs) and related materials have generated considerable interest, metallization are fundamental components to all semiconductor devices and integrated circuits. The essential roles of metallization systems are providing the desired electrical paths between the active region of the semiconductor and the external circuits through the metal interconnections and contacts. In this work, in-situ clean of native oxide, high temperature n-type, low temperature n-type and low temperature p-type ohmic metal systems have been studied. Argon ion mill was used to remove the native oxide prior to metal deposition. For high temperature process n-type GaAs ohmic contacts, Tungsten (W) and Tungsten Silicide (WSi) were used with an epitaxial grown graded Indium Gallium Arsenide (InGaAs) layer (0.2 eV) on GaAs. In addition, refractory metals, Molybdenum (Mo), was incorporated in the Gold-Germanium (AuGe) based on n-type GaAs ohmic contacts to replace conventional silver as barrier to prevent the reaction between ohmic metal and chlorine based plasma as well as the ohmic metallization intermixing which degrades the device performance. Finally, Indium/Gold-Beryllium (In/Au-Be) alloy has been developed as an ohmic contact for p-type GaAs to reduce the contact resistance. The Fermi-level pinning of GaAs has been dominated by the surface states. The Schottky barrier height of metal contacts are about 0.8 V regardless of the metal systems. By using p-n junction approach, barrier height of pulsed C-doped layers was achieved as high as 1.4 V. Arsenic implantation into GaAs method was also used to enhance the barrier height of 1.6 V.

  7. Modelling heavy metal and phosphorus balances for farming systems

    NARCIS (Netherlands)

    Keller, A.N.; Schulin, R.

    2003-01-01

    Accounting for agricultural activities such as P fertilization in regional models of heavy metal accumulation provides suitable sustainable management strategies to reduce nutrient surpluses and metal inputs in agricultural soils. Using the balance model PROTERRA-S, we assessed the phosphorus ( P),

  8. Liquid metal liner implosion systems with blade lattice for fusion

    International Nuclear Information System (INIS)

    Itoh, Yasuyuki; Fujiie, Yoichi

    1980-01-01

    In this paper, the liquid liner implosion systems with the blade lattice is proposed for the rotational stabilization of the liner inner surface which is facing a plasma in a fusion reactor. The blades are electrically conducting and inclined to the radial direction. Its major function is either acceleration or deceleration of the liner in the azimuthal direction. This system enables us to exclude the rotary mechanism for the liner rotation. In this system, the liner is formed as an annular flow of a liquid metal (the waterfall concept). Results show that there is no significant difference of the energy cost for the stabilization compared with the earlier proposed system where a liner is rotated rigidly before implosion. Furthermore, the application of the rotating blade lattice makes it possible to reduce the rotational kinetic energy required for the stabilization at turnaround, where the lattice acts as an impeller in the initial liner rotation. There is an optimum blade angle to maximize the compressed magnetic field energy inside the liner for a given driving energy. (author)

  9. Translocation of metal phosphate via the phosphate inorganic transport system of Escherichia coli

    NARCIS (Netherlands)

    van Veen, H.W; Abee, T.; Kortstee, G.J J; Konings, W.N; Zehnder, A.J B

    1994-01-01

    P-i transport via the phosphate inorganic transport system (Pit) of Escherichia coil was studied in natural and artificial membranes. P-i uptake via Pit is dependent on the presence of divalent cations, like Mg2+, Ca2+, Co2+, or Mn2+, which form a soluble, neutral metal phosphate (MeHPO(4)) complex.

  10. Hydroponics reducing effluent's heavy metals discharge.

    Science.gov (United States)

    Rababah, Abdellah; Al-Shuha, Ahmad

    2009-01-01

    This paper investigates the capacity of Nutrient Film Technique (NFT) to control effluent's heavy metals discharge. A commercial hydroponic system was adapted to irrigate lettuces with primary treated wastewater for studying the potential heavy metals removal. A second commercial hydroponic system was used to irrigate the same type of lettuces with nutrient solution and this system was used as a control. Results showed that lettuces grew well when irrigated with primary treated effluent in the commercial hydroponic system. The NFT-plant system heavy metals removal efficiency varied amongst the different elements, The system's removal efficiency for Cr was more than 92%, Ni more than 85%, in addition to more than 60% reduction of B, Pb, and Zn. Nonetheless, the NFT-plants system removal efficiencies for As, Cd and Cu were lower than 30%. Results show that lettuces accumulated heavy metals in leaves at concentrations higher than the maximum acceptable European and Australian levels. Therefore, non-edible plants such as flowers or pyrethrum are recommended as value added crops for the proposed NFT.

  11. Microgravity effects on electrodeposition of metals and metal-cermet mixtures

    Science.gov (United States)

    Maybee, George W.; Riley, Clyde; Coble, H. Dwain

    1987-01-01

    An experimental system, designed to investigate the potential advantages of electrodeposition in microgravity, is being developed by the McDonnell Douglas Astronautics Company-Huntsville Division and the University of Alabama in Huntsville. It is intended to fly as an Orbiter payload when NASA resumes STS operations. The system will provide power, thermal conditioning, command and control for the production of electrodeposits; system performance data will be recorded for post-flight analysis. Plated metal surfaces will be created using simple electrolytic cells with pure metal electrodes immersed in aqueous electrolytic solutions. Crystalline structure and other properties will be analyzed to identify differences between samples produced in flight and those obtained from ground-based operations.

  12. Metal hydride hydrogen and heat storage systems as enabling technology for spacecraft applications

    Energy Technology Data Exchange (ETDEWEB)

    Reissner, Alexander, E-mail: reissner@fotec.at [FOTEC Forschungs- und Technologietransfer GmbH, Viktor Kaplan Straße 2, 2700 Wiener Neustadt (Austria); University of Applied Sciences Wiener Neustadt, Johannes Gutenberg-Straße 3, 2700 Wiener Neustadt (Austria); Pawelke, Roland H.; Hummel, Stefan; Cabelka, Dusan [FOTEC Forschungs- und Technologietransfer GmbH, Viktor Kaplan Straße 2, 2700 Wiener Neustadt (Austria); Gerger, Joachim [University of Applied Sciences Wiener Neustadt, Johannes Gutenberg-Straße 3, 2700 Wiener Neustadt (Austria); Farnes, Jarle, E-mail: Jarle.farnes@prototech.no [CMR Prototech AS, Fantoftvegen 38, PO Box 6034, 5892 Bergen (Norway); Vik, Arild; Wernhus, Ivar; Svendsen, Tjalve [CMR Prototech AS, Fantoftvegen 38, PO Box 6034, 5892 Bergen (Norway); Schautz, Max, E-mail: max.schautz@esa.int [European Space Agency, ESTEC – Keplerlaan 1, 2201 AZ Noordwijk Zh (Netherlands); Geneste, Xavier, E-mail: xavier.geneste@esa.int [European Space Agency, ESTEC – Keplerlaan 1, 2201 AZ Noordwijk Zh (Netherlands)

    2015-10-05

    Highlights: • A metal hydride tank concept for heat and hydrogen storage is presented. • The tank is part of a closed-loop reversible fuel cell system for space application. • For several engineering issues specific to the spacecraft application, solutions have been developed. • The effect of water contamination has been approximated for Ti-doped NaAlH{sub 4}. • A novel heat exchanger design has been realized by Selective Laser Melting. - Abstract: The next generation of telecommunication satellites will demand a platform payload performance in the range of 30+ kW within the next 10 years. At this high power output, a Regenerative Fuel Cell Systems (RFCS) offers an efficiency advantage in specific energy density over lithium ion batteries. However, a RFCS creates a substantial amount of heat (60–70 kJ per mol H{sub 2}) during fuel cell operation. This requires a thermal hardware that accounts for up to 50% of RFCS mass budget. Thus the initial advantage in specific energy density is reduced. A metal hydride tank for combined storage of heat and hydrogen in a RFCS may overcome this constraint. Being part of a consortium in an ongoing European Space Agency project, FOTEC is building a technology demonstrator for such a combined hydrogen and heat storage system.

  13. Metal ion levels and lymphocyte counts

    DEFF Research Database (Denmark)

    Penny, Jeannette Ø; Varmarken, Jens-Erik; Ovesen, Ole

    2013-01-01

    BACKGROUND AND PURPOSE: Wear particles from metal-on-metal arthroplasties are under suspicion for adverse effects both locally and systemically, and the DePuy ASR Hip Resurfacing System (RHA) has above-average failure rates. We compared lymphocyte counts in RHA and total hip arthroplasty (THA) an....../ppb. INTERPRETATION: Circulating T-lymphocyte levels may decline after surgery, regardless of implant type. Metal ions-particularly cobalt-may have a general depressive effect on T- and B-lymphocyte levels. Registered with ClinicalTrials.gov under # NCT01113762.......BACKGROUND AND PURPOSE: Wear particles from metal-on-metal arthroplasties are under suspicion for adverse effects both locally and systemically, and the DePuy ASR Hip Resurfacing System (RHA) has above-average failure rates. We compared lymphocyte counts in RHA and total hip arthroplasty (THA....... RESULTS: The T-lymphocyte counts for both implant types declined over the 2-year period. This decline was statistically significant for CD3(+)CD8(+) in the THA group, with a regression coefficient of -0.04 × 10(9)cells/year (95% CI: -0.08 to -0.01). Regression analysis indicated a depressive effect...

  14. Competitive immobilization of Pb in an aqueous ternary-metals system by soluble phosphates with varying pH.

    Science.gov (United States)

    Zhang, Zhuo; Ren, Jie; Wang, Mei; Song, Xinlai; Zhang, Chao; Chen, Jiayu; Li, Fasheng; Guo, Guanlin

    2016-09-01

    Chemical immobilization by phosphates has been widely and successfully applied to treat Pb in wastewater and contaminated soils. Pb in wastewaters and soils, however, always coexists with other heavy metals and their competitive reactions with phosphates have not been quantitatively and systematically studied. In this approach, immobilization of Pb, Zn, and Cd by mono-, di-, and tripotassium phosphate (KH2PO4, K2HPO4, and K3PO4) was observed in the single- and ternary-metals solutions. The immobilization rates of the three metals were determined by the residual concentration. The mineral composition and structure of the precipitates were characterized by powder X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The results indicated that competitive reaction occurred in Pb-Zn-Cd ternary system, with immobilization rates decrease of system. The reaction of Pb with three phosphates exhibited intense competitiveness and the phosphates had a stronger affinity for Pb when Cl(-) was added. Pb-phosphate minerals formed by KH2PO4 with the better crystalline characteristics and largest size were very stable with a low dissolution rate (system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Determination of distribution pattern of the heavy metal concentrations in the potable network of Gachsaran by Geographical Information System (GIS

    Directory of Open Access Journals (Sweden)

    G Paraham

    2013-12-01

    . Methods: In this descriptive, cross-sectional study, samples were taken from11 spots of the drinking water distribution network and tested for concentration of 10 metals by Inductivity Coupled Ions Plasma (ICP method in summer of 2010. The research data were compared with national and international water standards. Then the distribution map of heavy metals concentrations in the drinking water wells of the region was prepared by using the Geographical Information System (GIS software. Data were analyzed by the Kruskal-Wallis tests. Results: In all samples, the average concentration of heavy metals were: Arsenic 0.54, Cadmium 0.05, Zinc 55.9, Lead 0.18, Copper .82, Chromium 1.6, Barium 36.5, Selenium0.5, Mercury 0.1 and Silver 0.05 micrograms per liter and was less than the water quality standard. Conclusion: Based on the results obtained, it can be concluded that concentrations of heavy metals in Gachsaran’s drinking water distribution network are not higher than national and international standards and therefore not harmful for people. Key words: Heavy metals, Distribution network, Gachsaran, geographical information system (GIS

  16. Impact of heavy metals on the female reproductive system

    Directory of Open Access Journals (Sweden)

    Piotr Rzymski

    2015-05-01

    Environmental deterioration can lead to the elevated risk of human exposure to heavy metals, and consequently, health implications including disturbances in reproduction. It is therefore important to continue the investigations on metal-induced mechanisms of fertility impairment on the genetic, epigenetic and biochemical level.

  17. Features of systems for operational control of WWER vessel metal, used in the USSR

    International Nuclear Information System (INIS)

    Yurchenko, Yu.F.

    1987-01-01

    The report descrides key features of an improved system developed to serve for monitoring the soundness of the metal material of the operating high-pressure reactor vessels in nuclear power generation plants in the Soviet Union. The most important feature is that an external monitoring subsystem is incorporated in the system. The subsystem has the advantage of ensuring the following: high defect detectability due to the absense of austenite lining on the outer surface of the reactor vessel; implementation of monitoring work without removing in-pile structures in parallel with preventive maintenance work during annual partial fuel replacement; and application of other monitoring techniques, such as accoustic emission, in future. Another feature is that radiography by iridium-192 and cobalt-90 is employed to support the external monitoring of the metal material of the nozzle component. An optical periscope is incorporated to permit detailed visual inspection of the lining surface of the inner face of a reactor vessel. Data on the coordinates of defects are displayed on a TV screen and recorded and reproduced by a video recorder. The system also uses an 'echo method' for ultrasonic monitoring and a high sensitive 'tandem method' for detecting vertically oriented defects. The entire system can be operated by remote control. (Nogami, K.)

  18. Incorporation of metal bioavailability into regulatory frameworks-metal exposure in water and sediment

    Energy Technology Data Exchange (ETDEWEB)

    Ahlf, Wolfgang [Inst. of Environmental Tech. and Energy Economics, TUHH, Hamburg (Germany); Drost, Wiebke [Umweltpruefung Chemikalien IV, Umweltbundesamt, Dessau (Germany); Heise, Susanne [Dept. of Life Sciences, HAW, Hamburg (Germany)

    2009-10-15

    Background, aim, and scope The cause for this position paper is the impression that risk assessors consider primarily the concentration of free metal ions dissolved in solution controlling metal bioavailability in aquatic systems. Aiming at a more realistic risk assessment of metals, bioavailability has to be discussed under the scope of main uptake routes of metals to organisms. Materials and methods On the basis of a review on the literature relating to bioavailability approaches, this work discusses the incorporation of metal bioavailability into the risk assessment of metals in the context of metal exposure. Results The biotic ligand model (BLM) and the concept of sulfide bound metals described by the ratio of simultaneously extracted metals and acid volatile sulfide concept (AVS) have been developed to consider the bioavailability of metals. Both approaches assume that the free ion concentration is the most relevant exposure pathway. However, apart from geochemical conditions, which control free metal concentration, bioavailability is additionally a result of contaminant/particle interaction and of organisms' activity. Asking for the relevant exposure pathways for inorganic metals to organisms, the compartments' water and sediment have been evaluated and also the importance of contaminated food. (orig.)

  19. The identification of 'hotspots' of heavy metal pollution in soil-rice systems at a regional scale in eastern China.

    Science.gov (United States)

    Li, Wanlu; Xu, Binbin; Song, Qiujin; Liu, Xingmei; Xu, Jianming; Brookes, Philip C

    2014-02-15

    Chinese agricultural soils and crops are suffering from increasing damage from heavy metals, which are introduced from various pollution sources including agriculture, traffic, mining and especially the flourishing private metal recycling industry. In this study, 219 pairs of rice grain and corresponding soil samples were collected from Wenling in Zhejiang Province to identify the spatial relationship and pollution hotspots of Cd, Cu, Ni and Zn in the soil-rice system. The mean soil concentrations of heavy metals were 0.316 mg kg(-1) for Cd, 47.3 mg kg(-1) for Cu, 31.7 mg kg(-1) for Ni and 131 mg kg(-1) for Zn, and the metal concentrations in rice grain were 0.132 mg kg(-1) for Cd, 2.46 mg kg(-1) for Cu, 0.223 mg kg(-1) for Ni and 17.4 mg kg(-1) for Zn. The coefficient of variability (CV) of soil Cd, Cu and rice Cd were 147%, 146% and 180%, respectively, indicating an extensive variability. While the CVs of other metals ranged from 23.4% to 84.3% with a moderate variability. Kriging interpolation procedure and the Local Moran's I index detected the locations of pollution hotspots of these four metals. Cd and Cu had a very similar spatial pattern, with contamination hotspots located simultaneously in the northwestern part of the study area, and there were obvious hotspots for soil Zn in the north area, while in the northeast for soil Ni. The existence of hotspots may be due to industrialization and other anthropogenic activities. An Enrichment Index (EI) was employed to measure the uptake of heavy metals by rice. The results indicated that the accumulation and availability of heavy metals in the soil-rice system may be influenced by both soil heavy metal concentrations and soil physico-chemical properties. Cross-correlograms quantitatively illustrated that EIs were significantly correlated with soil properties. Soil pH and organic matter were the most important factors controlling the uptake of heavy metals by rice. As results, positive measures should be taken into

  20. Bioassessment of heavy metal toxicity and enhancement of heavy metal removal by sulfate-reducing bacteria in the presence of zero valent iron.

    Science.gov (United States)

    Guo, Jing; Kang, Yong; Feng, Ying

    2017-12-01

    A simple and valid toxicity evaluation of Zn 2+ , Mn 2+ and Cr 6+ on sulfate-reducing bacteria (SRB) and heavy metal removal were investigated using the SRB system and SRB+Fe 0 system. The heavy metal toxicity coefficient (β) and the heavy metal concentration resulting in 50% inhibition of sulfate reduction (I) from a modeling process were proposed to evaluate the heavy metal toxicity and nonlinear regression was applied to search for evaluation indices β and I. The heavy metal toxicity order was Cr 6+  > Mn 2+  > Zn 2+ . Compared with the SRB system, the SRB+Fe 0 system exhibited a better capability for sulfate reduction and heavy metal removal. The heavy metal removal was above 99% in the SRB+Fe 0 system, except for Mn 2+ . The energy-dispersive spectroscopy (EDS) analysis showed that the precipitates were removed primarily as sulfide for Zn 2+ and hydroxide for Mn 2+ and Cr 6+ .The method of evaluating the heavy metal toxicity on SRB was of great significance to understand the fundamentals of the heavy metal toxicity and inhibition effects on the microorganism and regulate the process of microbial sulfate reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Removal of contaminated asphalt layers by using heat generating powder metallic systems

    International Nuclear Information System (INIS)

    Barinov, A.S.; Karlina, O.K.; Ojovan, M.I.

    1996-01-01

    Heat generating systems on the base of powder metallic fuel were used for the removal of contaminated asphalt layers. Decontamination of spots which had complex geometric form was performed. Asphalt layers with deep contamination were removed essentially all radionuclides being retained in asphalt residue. Only a small part (1 - 2 %) of radionuclides could pass to combustion slag. No radionuclides were detected in aerosol-gas phase during decontamination process

  2. Extraterrestrial Metals Processing, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Extraterrestrial Metals Processing (EMP) system produces iron, silicon, and light metals from Mars, Moon, or asteroid resources in support of advanced human...

  3. Tethered Transition Metals Promoted Photocatalytic System for Efficient Hydrogen Evolutions

    KAUST Repository

    Takanabe, Kazuhiro

    2015-03-05

    The present invention is directed, at least in part, to a process for improving the efficiency of a photocatalyst (a semiconductor photocatalyst) by tethering (depositing) a metal (e.g., metal ions of a late transition metal, such as nickel) to the semiconductor (photocatalyst) surface through the use of an organic ligand. More specifically, 1,2-ethanedithiol (EDT) functions as an excellent molecular linker (organic ligand) to attach a transition metal complex (e.g., nickel (Ni.sup.2+ ions)) to the semiconductor surface, which can be in the form of a cadmium sulfide surface. The photocatalyst has particular utility in generating hydrogen from H.sub.2S.

  4. Tethered Transition Metals Promoted Photocatalytic System for Efficient Hydrogen Evolutions

    KAUST Repository

    Takanabe, Kazuhiro; Isimjan, Tayirjan; Yu, Weili; Del Gobbo, Silvano; Xu, Wei

    2015-01-01

    The present invention is directed, at least in part, to a process for improving the efficiency of a photocatalyst (a semiconductor photocatalyst) by tethering (depositing) a metal (e.g., metal ions of a late transition metal, such as nickel) to the semiconductor (photocatalyst) surface through the use of an organic ligand. More specifically, 1,2-ethanedithiol (EDT) functions as an excellent molecular linker (organic ligand) to attach a transition metal complex (e.g., nickel (Ni.sup.2+ ions)) to the semiconductor surface, which can be in the form of a cadmium sulfide surface. The photocatalyst has particular utility in generating hydrogen from H.sub.2S.

  5. Irradiation performance of metallic fuels

    International Nuclear Information System (INIS)

    Pahl, R.G.; Lahm, C.E.; Porter, D.L.; Batte, G.L.; Hofman, G.L.

    1989-01-01

    Argonne National Laboratory has been working for the past five years to develop and demonstrate the Integral Fast Reactor (IFR) concept. The concept involves a closed system for fast-reactor power generation and on-site fuel reprocessing, both designed specifically around the use of metallic fuel. The Experimental Breeder Reactor-II (EBR-II) has used metallic fuel for all of its 25-year life. In 1985, tests were begun to examine the irradiation performance of advanced-design metallic fuel systems based on U-Zr or U-Pu-Zr fuels. These tests have demonstrated the viable performance of these fuel systems to high burnup. The initial testing program will be described in this paper. 2 figs

  6. Comparison of fracture resistance between cast, CAD/CAM milling, and direct metal laser sintering metal post systems.

    Science.gov (United States)

    Bilgin, Mehmet Selim; Erdem, Ali; Dilber, Erhan; Ersoy, İbrahim

    2016-01-01

    The purpose of this study was to compare the fracture resistance of Co-Cr post-cores fabricated with 3 different techniques: traditional casting (TC), computer-aided design and manufacturing (CAD/CAM) milling (CCM) and direct metal laser sintering (DMLS). Forty intact human mandibular premolar were endodontically treated. The roots were then randomly divided into four groups according to the post systems: the control group was only filled with gutta percha. Co-Cr metal posts were fabricated with TC, CCM and DMLS in the other three groups. The posts were luted with a resin cement and subjected to compression test at a crosshead speed of 1mm/min. The statistical analysis of the data was performed using one-way analysis of variance (ANOVA) and multiple comparison post hoc Tukey tests (α=.05). The samples were examined under a stereomicroscope with ×20 magnification for the evaluation of the fracture types. The mean fracture loads were 432.69 N for control, 608.89 N for TC, 689.40 N for DMLS and 959.26 N for CCM. One-way ANOVA revealed significant difference between the groups (pmetal posts fabricated by CCM and DMLS could be an alternative to TC processing in daily clinical application. Copyright © 2015 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  7. Neutron scattering for investigation into the connection between phonons and diffusion in metallic systems

    International Nuclear Information System (INIS)

    Herzig, C.

    1995-01-01

    For examining the connection between the diffusion systematics and the lattice dynamics of the body-centered cubic metals, the temperature dependence of the self-diffusion (radiotracer technique) and the phonon dispersion (neutron scattering) have been measured in selected systems. In continuation of previous studies, the goal of the examinations reported was to put the earlier developed phonon-related diffusion model on a broader experimental basis, in order to perform verifying analyses. The phonon dispersion of the group 5 metal Nb has been measured up to high temperatures. In contrast to the values measured for the group 4 (β-Zr) and group 6 (Cr) metals, the dispersion in Nb revealed an only very weak temperature dependence. The exceptional case of the bcc β-Tl has been examined by measuring the diffusion and the dispersion in the β-T 83 In 17 alloy. Significant deviations from the conditions in the bcc transition metals have been found. Self-diffusion has been measured for the first time in Ba and β-Sc. Their diffusion systematics correlate with electron configuration. The influence of the d-electron concentration on the diffusion systematics has been measured in Ti-Mo and Hf-Nb alloys, the results backing the predictions of the phonon-related diffusion model. (orig.) [de

  8. Application of Sargassum biomass to remove heavy metal ions from synthetic multi-metal solutions and urban storm water runoff.

    Science.gov (United States)

    Vijayaraghavan, K; Teo, Ting Ting; Balasubramanian, R; Joshi, Umid Man

    2009-05-30

    The ability of Sargassum sp. to biosorb four metal ions, namely lead, copper, zinc, and manganese from a synthetic multi-solute system and real storm water runoff has been investigated for the first time. Experiments on synthetic multi-solute systems revealed that Sargassum performed well in the biosorption of all four metal ions, with preference towards Pb, followed by Cu, Zn, and Mn. The solution pH strongly affected the metal biosorption, with pH 6 being identified as the optimal condition for achieving maximum biosorption. Experiments at different biosorbent dosages revealed that good biosorption capacity as well as high metal removal efficiency was observed at 3g/L. The biosorption kinetics was found to be fast with equilibrium being attained within 50 min. According to the Langmuir isotherm model, Sargassum exhibited maximum uptakes of 214, 67.5, 24.2 and 20.2mg/g for lead, copper, zinc, and manganese, respectively in single-solute systems. In multi-metal systems, strong competition between four metal ions in terms of occupancy binding sites was observed, and Sargassum showed preference in the order of Pb>Cu>Zn>Mn. The application of Sargassum to remove four heavy metal ions in real storm water runoff revealed that the biomass was capable of removing the heavy metal ions. However, the biosorption performance was slightly lower compared to that of synthetic metal solutions. Several factors were responsible for this difference, and the most important factor is the presence of other contaminants such as anions, organics, and other trace metals in the runoff.

  9. Nissei incas system (FP-Plan) which databased the skilled sense and experiences in molding metal design. Kanagata sekkei ni okeru kan ya keiken wo data base kashita Nissei incas system (FP-plan)

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, K. (Nissei Plastic Industrial Co. Ltd., Nagano (Japan))

    1992-01-01

    Mold System Department of Nissei Resin Industies Co. has developed NISSEI INCAS SYSTEM, which is a CAD/CAM/CAE system specially for injection metal molding. Generally, high analysis methods such as flow analysis method have been considered for CAE, though, when making it to be linked with designing works for injection molding metals, economic conditions will not make a balance. Since authors have judged that to make an accurate mold metal drawing more quickly, before adopting such kind of flow analysis, more inportant and fundamental problems might be remained, they have started to develope their own system called FP-PLAN. This system, for example, is a software, which paying mainly attention to the most important and common problems for molding metal design to be solved, such as setting of shrinking factor, gate and runner design, estimation of cavity inside pressure, etc. Specially, they have developed only small molding products (product volume shall be under 200 cm {sup 3}). In this report, outlines of FP-PLAN such as the characteristics and programs have been intrduced. 4 figs., 2 tabs.

  10. Automated ion-exchange system for the radiochemical separation of the noble metals

    International Nuclear Information System (INIS)

    Parry, S.J.

    1980-01-01

    Ion-exchange separation is particularly suitable for mechanisation and automated ion exchange has been applied to the activation analysis of biological and environmental samples. In this work a system has been designed for experimental studies, which can be adapted for different modes of operation. The equipment is based on a large-volume sampler for the automatic presentation of 500 ml of liquid to a sampling probe. The sample is delivered to the ion-exchange column by means of a peristaltic pump. The purpose of this work was to automate a procedure for separating the noble metals from irradiated geological samples, for neutron-activation analysis. The process of digesting the rock sample is carried out manually in 30 min and is not suited to unattended operation. The volume of the resulting liquid sample may be 100 ml and so the manual separation step may take as long as 1.25 h per sample. The reason for automating this part of the procedure is to reduce the separation time for a group of five samples and consequently to improve the sensitivity of the analysis for radionuclides with short half-lives. This paper describes the automatic ion-exchange system and the ways in which it can be used. The mode of operation for the separation of the noble metals is given in detail. The reproducibility of the system has been assessed by repeated measurements on a standard reference matte. (author)

  11. Validation of KENO, ANISN and Hansen-Roach cross-section set on plutonium oxide and metal fuel system

    International Nuclear Information System (INIS)

    Matsumoto, Tadakuni; Yumoto, Ryozo; Nakano, Koh.

    1980-01-01

    In the previous report, the authors discussed the validity of KENO, ANISN and Hansen-Roach 16 group cross-section set on the critical plutonium nitrate solution systems with various geometries, absorbers and neutron interactions. The purpose of the present report is to examine the validity of the same calculation systems on the homogeneous plutonium oxide and plutonium-uranium mixed oxide fuels with various density values. Eleven experiments adopted for validation are summarized. First six experiments were performed at Pacific Northwest Laboratory of Battelle Memorial Institute, and the remaining five at Los Alamos Scientific Laboratory. The characteristics of core fuel are given, and the isotopic composition of plutonium, the relation between H/(Pu + U) atomic ratio and fuel density as compared with the atomic ratios of PuO 2 and mixed oxides in powder storage and pellet fabrication processes, and critical core dimensions and reflector conditions are shown. The effective multiplication factors were calculated with the KENO code. In case of the metal fuels with simple sphere geometry, additional calculations with the ANISN code were performed. The criticality calculation system composed of KENO, ANISN and Hansen-Roach cross-section set was found to be valid for calculating the criticality on plutonium oxide, plutonium-uranium mixed oxide, plutonium metal and uranium metal fuel systems as well as on plutonium solution systems with various geometries, absorbers and neutron interactions. There seems to remain some problems in the method for evaluating experimental correction. Some discussions foloow. (Wakatsuki, Y.)

  12. Effects of multi-metal toxicity on the performance of sewage treatment system during the festival of colors (Holi) in India.

    Science.gov (United States)

    Tyagi, Vinay Kumar; Bhatia, Akanksha; Gaur, Rubia Zahid; Khan, Abid Ali; Ali, Muntajir; Khursheed, Anwar; Kazmi, Absar Ahmad

    2012-12-01

    The present study investigated the effects of heavy metals (Ni, Zn, Cd, Cu, and Pb) toxicity on the performance of 18 MLD activated sludge process-based sewage treatment plant (STP) during celebration of Holi (festival of colors in India). The composite sampling (n = 32) was carried out during the entire study period. The findings show a significant decrease in chemical oxygen demand removal efficiency (20%) of activated sludge system, after receiving the heavy metals laden wastewater. A significant reduction of 40% and 60% were observed in MLVSS/MLSS ratio and specific oxygen uptake rate, which eventually led to a substantial decrease in biomass growth yield (from 0.54 to 0.17). The toxic effect of metals ions was also observed on protozoan population. Out of the 12 mixed liquor species recorded, only two ciliates species of Vorticella and Epistylis exhibited the greater tolerance against heavy metals toxicity. Furthermore, activated sludge shows the highest metal adsorption affinity for Cu, followed by Zn, Pb, Ni, and Cd (Cu > Zn > Pb > Ni > Cd). Finally, this study proves the robustness of activated sludge system against the sudden increase in heavy metal toxicity since it recovered the earlier good quality performance within 5 days.

  13. Remediation of groundwater containing radionuclides and heavy metals using ion exchange and the AlgaSORB reg-sign biosorbent system

    International Nuclear Information System (INIS)

    Feiler, H.D.; Darnall, D.W.

    1991-01-01

    Bio-Recovery Systems, Inc. (BRS) studied the application of an immobilized algal biomass, termed AlgaSORB reg-sign, which has high affinity for heavy metal ions to DOE-contaminated groundwaters. The material can be packed into columns similar to commercial ion exchange resins. Dilute solutions containing heavy metals are passed through columns where metals are absorbed by the AlgaSORB reg-sign resins. Once saturated, metal ions can be stripped from the resin biomass in a highly concentrated solution. Groundwaters contaminated with heavy metal ions from three different Department of Energy (DOE) sites: Savannah River, Hanford and the Oak Ridge Y-12 Plant were studied. The objective was to perform bench-scale treatability studies to establish treatment protocols and to optimize an AlgaSORB reg-sign/ion exchange technology system to remove and recover toxic metal ions from these contaminated groundwaters. The specialty ion exchange/AlgaSORB reg-sign resins tested in these studies show promise for selectively removing chromium, mercury and uranium from contaminated groundwater at DOE sites. The data show that effluents which satisfy the allowable metal ion limits are possible and most likely achievable. The use of these highly selective resins also offer advantages in terms of cost/benefit, risk and scheduling. Their high selectivity allows for high capacity and opportunities for recovery of removed constituents due to high pollutant concentration possible (3 to 4 orders of magnitude). Ion exchange is a proven technology which is easily automated and can be cost-effective, depending on the application

  14. Implementation of Cyber-Physical Production Systems for Quality Prediction and Operation Control in Metal Casting.

    Science.gov (United States)

    Lee, JuneHyuck; Noh, Sang Do; Kim, Hyun-Jung; Kang, Yong-Shin

    2018-05-04

    The prediction of internal defects of metal casting immediately after the casting process saves unnecessary time and money by reducing the amount of inputs into the next stage, such as the machining process, and enables flexible scheduling. Cyber-physical production systems (CPPS) perfectly fulfill the aforementioned requirements. This study deals with the implementation of CPPS in a real factory to predict the quality of metal casting and operation control. First, a CPPS architecture framework for quality prediction and operation control in metal-casting production was designed. The framework describes collaboration among internet of things (IoT), artificial intelligence, simulations, manufacturing execution systems, and advanced planning and scheduling systems. Subsequently, the implementation of the CPPS in actual plants is described. Temperature is a major factor that affects casting quality, and thus, temperature sensors and IoT communication devices were attached to casting machines. The well-known NoSQL database, HBase and the high-speed processing/analysis tool, Spark, are used for IoT repository and data pre-processing, respectively. Many machine learning algorithms such as decision tree, random forest, artificial neural network, and support vector machine were used for quality prediction and compared with R software. Finally, the operation of the entire system is demonstrated through a CPPS dashboard. In an era in which most CPPS-related studies are conducted on high-level abstract models, this study describes more specific architectural frameworks, use cases, usable software, and analytical methodologies. In addition, this study verifies the usefulness of CPPS by estimating quantitative effects. This is expected to contribute to the proliferation of CPPS in the industry.

  15. Implementation of Cyber-Physical Production Systems for Quality Prediction and Operation Control in Metal Casting

    Directory of Open Access Journals (Sweden)

    JuneHyuck Lee

    2018-05-01

    Full Text Available The prediction of internal defects of metal casting immediately after the casting process saves unnecessary time and money by reducing the amount of inputs into the next stage, such as the machining process, and enables flexible scheduling. Cyber-physical production systems (CPPS perfectly fulfill the aforementioned requirements. This study deals with the implementation of CPPS in a real factory to predict the quality of metal casting and operation control. First, a CPPS architecture framework for quality prediction and operation control in metal-casting production was designed. The framework describes collaboration among internet of things (IoT, artificial intelligence, simulations, manufacturing execution systems, and advanced planning and scheduling systems. Subsequently, the implementation of the CPPS in actual plants is described. Temperature is a major factor that affects casting quality, and thus, temperature sensors and IoT communication devices were attached to casting machines. The well-known NoSQL database, HBase and the high-speed processing/analysis tool, Spark, are used for IoT repository and data pre-processing, respectively. Many machine learning algorithms such as decision tree, random forest, artificial neural network, and support vector machine were used for quality prediction and compared with R software. Finally, the operation of the entire system is demonstrated through a CPPS dashboard. In an era in which most CPPS-related studies are conducted on high-level abstract models, this study describes more specific architectural frameworks, use cases, usable software, and analytical methodologies. In addition, this study verifies the usefulness of CPPS by estimating quantitative effects. This is expected to contribute to the proliferation of CPPS in the industry.

  16. Implementation of Cyber-Physical Production Systems for Quality Prediction and Operation Control in Metal Casting

    Science.gov (United States)

    Lee, JuneHyuck; Noh, Sang Do; Kim, Hyun-Jung; Kang, Yong-Shin

    2018-01-01

    The prediction of internal defects of metal casting immediately after the casting process saves unnecessary time and money by reducing the amount of inputs into the next stage, such as the machining process, and enables flexible scheduling. Cyber-physical production systems (CPPS) perfectly fulfill the aforementioned requirements. This study deals with the implementation of CPPS in a real factory to predict the quality of metal casting and operation control. First, a CPPS architecture framework for quality prediction and operation control in metal-casting production was designed. The framework describes collaboration among internet of things (IoT), artificial intelligence, simulations, manufacturing execution systems, and advanced planning and scheduling systems. Subsequently, the implementation of the CPPS in actual plants is described. Temperature is a major factor that affects casting quality, and thus, temperature sensors and IoT communication devices were attached to casting machines. The well-known NoSQL database, HBase and the high-speed processing/analysis tool, Spark, are used for IoT repository and data pre-processing, respectively. Many machine learning algorithms such as decision tree, random forest, artificial neural network, and support vector machine were used for quality prediction and compared with R software. Finally, the operation of the entire system is demonstrated through a CPPS dashboard. In an era in which most CPPS-related studies are conducted on high-level abstract models, this study describes more specific architectural frameworks, use cases, usable software, and analytical methodologies. In addition, this study verifies the usefulness of CPPS by estimating quantitative effects. This is expected to contribute to the proliferation of CPPS in the industry. PMID:29734699

  17. Adlayer Core-Level Shifts of Random Metal Overlayers on Transition-Metal Substrates

    DEFF Research Database (Denmark)

    Ganduglia-Pirovano, M. V.; Kudrnovský, J.; Scheffler, M.

    1997-01-01

    and the screening effects induced by the core hole, and study the influence of the alloy composition for a number of noble metal-transition metal systems. Our analysis clearly indicates the importance of final-state screening effects for the interpretation of measured core-level shifts. Calculated deviations from...

  18. Functionalised metal-organic frameworks : A novel approach to stabilising single metal atoms

    NARCIS (Netherlands)

    Szilagyi, P.A.; Rogers, D. M.; Zaiser, I.; Callini, E; Turner, Stuart; Borgschulte, A; Züttel, A.; Geerlings, J.J.C.; Hirscher, M; Dam, B.

    2017-01-01

    We have investigated the potential of metal-organic frameworks for immobilising single atoms of transition metals using a model system of Pd supported on NH2-MIL-101(Cr). Our transmission electron microscopy and in situ Raman spectroscopy results give evidence for the first time that

  19. Heavy metals in intensive greenhouse vegetable production systems along Yellow Sea of China: Levels, transfer and health risk.

    Science.gov (United States)

    Hu, Wenyou; Huang, Biao; Tian, Kang; Holm, Peter E; Zhang, Yanxia

    2017-01-01

    Recently, greenhouse vegetable production (GVP) has grown rapidly and counts a large proportion of vegetable production in China. In this study, the accumulation, health risk and threshold values of selected heavy metals were evaluated systematically. A total of 120 paired soil and vegetable samples were collected from three typical intensive GVP systems along the Yellow Sea of China. Mean concentrations of Cd, As, Hg, Pb, Cu and Zn in greenhouse soils were 0.21, 7.12, 0.05, 19.81, 24.95 and 94.11 mg kg -1 , respectively. Compared to rootstalk and fruit vegetables, leafy vegetables had relatively high concentrations and transfer factors of heavy metals. The accumulation of heavy metals in soils was affected by soil pH and soil organic matter. The calculated hazard quotients (HQ) of the heavy metals by vegetable consumption decreased in the order of leafy > rootstalk > fruit vegetables with hazard index (HI) values of 0.61, 0.33 and 0.26, respectively. The HI values were all below 1, which indicates that there is a low risk of greenhouse vegetable consumption. Soil threshold values (STVs) of heavy metals in GVP system were established according to the health risk assessment. The relatively lower transfer factors of rootstalk and fruit vegetables and higher STVs suggest that these types of vegetables are more suitable for cultivation in greenhouse soils. This study will provide an useful reference for controlling heavy metals and developing sustainable GVP. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Antimicrobial resistance, heavy metal resistance and integron content in bacteria isolated from a South African tilapia aquaculture system.

    Science.gov (United States)

    Chenia, Hafizah Y; Jacobs, Anelet

    2017-11-21

    Antibacterial compounds and metals co-select for antimicrobial resistance when bacteria harbour resistance genes towards both types of compounds, facilitating the proliferation and evolution of antimicrobial and heavy metal resistance. Antimicrobial and heavy metal resistance indices of 42 Gram-negative bacteria from a tilapia aquaculture system were determined to identify possible correlations between these phenotypes. Agar dilution assays were carried out to determine susceptibility to cadmium, copper, lead, mercury, chromate and zinc, while susceptibility to 21 antimicrobial agents was investigated by disk diffusion assays. Presence of merA, the mercury resistance gene, was determined by dot-blot hybridizations and PCR. Association of mercury resistance with integrons and transposon Tn21 was also investigated by PCR. Isolates displayed a high frequency of antimicrobial (erythromycin: 100%; ampicillin: 85%; trimethoprim: 78%) and heavy metal (Zn2+: 95%; Cd2+: 91%) resistance. No correlation was established between heavy metal and multiple antibiotic resistance indices. Significant positive correlations were observed between heavy metal resistance profiles, indices, Cu2+ and Cr3+ resistance with erythromycin resistance. Significant positive correlations were observed between merA (24%)/Tn21 (24%) presence and heavy metal resistance profiles and indices; however, significant negative correlations were obtained between integron-associated qacE∆1 (43%) and sulI (26%) gene presence and heavy metal resistance indices. Heavy metal and antimicrobial agents co-select for resistance, with fish-associated, resistant bacteria demonstrating simultaneous heavy metal resistance. Thus, care should be taken when using anti-fouling heavy metals as feed additives in aquaculture facilities.

  1. Metal fuel safety performance

    International Nuclear Information System (INIS)

    Miles, K.J. Jr.; Tentner, A.M.

    1988-01-01

    The current development of breeder reactor systems has lead to the renewed interest in metal fuels as the driver material. Modeling efforts were begun to provide a mechanistic description of the metal fuel during anticipated and hypothetical transients within the context of the SAS4A accident analysis code system. Through validation exercises using experimental results of metal fuel TREAT tests, confidence is being developed on the nature and accuracy of the modeling and implementation. Prefailure characterization, transient pin response, margins to failure, axial in-pin fuel relocation prior to cladding breach, and molten fuel relocation after cladding breach are considered. Transient time scales ranging from milliseconds to many hours can be studied with all the reactivity feedbacks evaluated

  2. Transition metal mediated transformations of small molecules

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Ayusman [Pennsylvania State Univ., University Park, PA (United States)

    2017-03-08

    Catalysis at metal centers is of great scientific, as well as practical, importance because of the high efficiency, high specificity, and low energy demands often associated with such systems. The two major themes of our research are (a) the design of metal-based systems for the synthesis of novel classes of polymers and (b) the identification of new metal-catalyzed systems for the conversion of biomass to fuels and chemicals, and related “green” chemical processes.

  3. Analysis of the tight-binding description of the structure of metallic 2D systems

    International Nuclear Information System (INIS)

    Baquero, R.

    1990-12-01

    Bidimensional metallic systems as interfaces, quantum wells and superlattices with sharp interfaces became recently available and their properties can now be experimentally studied in detail. To calculate the Local Density of States (LDOS) for surfaces, interfaces, quantum wells and superlattices we use empirical tight-binding Hamiltonians together with the Green function matching method (GFM). In this paper we show some examples of our results employing the method just outlined to describe metallic 2D systems. In particular, we refer briefly to the effect on the LDOS of the very recently established contraction of the first interatomic layer distance in the Ta(001) surface. We then discuss the Nb-V ideal (100) interface and conclude that under certain conditions the V-side of an interface can show magnetism as the V(001) surface does. As a last example, we present a calculation that relates the changes with gold coverage of the reaction rate of the catalytic reaction of cyclohexene into benzene on a Pt(001) surface to the changes on the LDOS of the outermost Pt atomic layer. We show that the behavior of the LDOS around the Fermi level is an important factor to the explanation of the behavior of this catalytic reaction. We conclude by stating that the empirical tight-binding method is a very simple and useful tool for the description of 2D metallic systems. The advantage is that the computational demands are low and all the ingredients to take full profit of this method are available (reliable tight-binding parameters and suitable methods for the calculation of the Green function). (author). 14 refs, 3 figs

  4. Tunable all-optical plasmonic rectifier in nanoscale metal-insulator-metal waveguides.

    Science.gov (United States)

    Xu, Yi; Wang, Xiaomeng; Deng, Haidong; Guo, Kangxian

    2014-10-15

    We propose a tunable all-optical plasmonic rectifier based on the nonlinear Fano resonance in a metal-insulator-metal plasmonic waveguide and cavities coupling system. We develop a theoretical model based on the temporal coupled-mode theory to study the device physics of the nanoscale rectifier. We further demonstrate via the finite difference time domain numerical experiment that our idea can be realized in a plasmonic system with an ultracompact size of ~120×800  nm². The tunable plasmonic rectifier could facilitate the all-optical signal processing in nanoscale.

  5. Methods for recovering metals from electronic waste, and related systems

    Science.gov (United States)

    Lister, Tedd E; Parkman, Jacob A; Diaz Aldana, Luis A; Clark, Gemma; Dufek, Eric J; Keller, Philip

    2017-10-03

    A method of recovering metals from electronic waste comprises providing a powder comprising electronic waste in at least a first reactor and a second reactor and providing an electrolyte comprising at least ferric ions in an electrochemical cell in fluid communication with the first reactor and the second reactor. The method further includes contacting the powders within the first reactor and the second reactor with the electrolyte to dissolve at least one base metal from each reactor into the electrolyte and reduce at least some of the ferric ions to ferrous ions. The ferrous ions are oxidized at an anode of the electrochemical cell to regenerate the ferric ions. The powder within the second reactor comprises a higher weight percent of the at least one base metal than the powder in the first reactor. Additional methods of recovering metals from electronic waste are also described, as well as an apparatus of recovering metals from electronic waste.

  6. Metal-enhanced galactic winds. I

    International Nuclear Information System (INIS)

    Vader, J.P.

    1986-01-01

    Supernova-driven gas loss during the early evolution of elliptical galaxies is considered as a possible explanation for the correlations among the observed chemical and structural properties of these systems. Mass loss from systems with a chemically homogeneous interstellar medium does not work. It is pointed out that supernova-driven winds are in fact metal-enhanced with respect to the star-forming gas because the metal production of any supernova that drives the wind is directly flushed out of the galaxy. The fraction of the total metal production lost in the wind is thus at least as large as the fraction epsilon(z) of supernovae that power the wind, independent of the total mass loss. As a corollary, the yield of heavy elements that are recycled in the galaxy is reduced by a factor 1 - epsilon(z). Metal-enhanced galactic winds, which can carry away a large fraction of the metal production in spite of a moderate total mass loss, offer a promising explanation for the low metallicities of dwarf elliptical galaxies. 62 references

  7. Comparison of filter media materials for heavy metal removal from urban stormwater runoff using biofiltration systems.

    Science.gov (United States)

    Lim, H S; Lim, W; Hu, J Y; Ziegler, A; Ong, S L

    2015-01-01

    The filter media in biofiltration systems play an important role in removing potentially harmful pollutants from urban stormwater runoff. This study compares the heavy metal removal potential (Cu, Zn, Cd, Pb) of five materials (potting soil, compost, coconut coir, sludge and a commercial mix) using laboratory columns. Total/dissolved organic carbon (TOC/DOC) was also analysed because some of the test materials had high carbon content which affects heavy metal uptake/release. Potting soil and the commercial mix offered the best metal uptake when dosed with low (Cu: 44.78 μg/L, Zn: 436.4 μg/L, Cd, 1.82 μg/L, Pb: 51.32 μg/L) and high concentrations of heavy metals (Cu: 241 μg/L, Zn: 1127 μg/L, Cd: 4.57 μg/L, Pb: 90.25 μg/L). Compost and sludge also had high removal efficiencies (>90%). Heavy metal leaching from these materials was negligible. A one-month dry period between dosing experiments did not affect metal removal efficiencies. TOC concentrations from all materials increased after the dry period. Heavy metal removal was not affected by filter media depth (600 mm vs. 300 mm). Heavy metals tended to accumulate at the upper 5 cm of the filter media although potting soil showed bottom-enriched concentrations. We recommend using potting soil as the principal media mixed with compost or sludge since these materials perform well and are readily available. The use of renewable materials commonly found in Singapore supports a sustainable approach to urban water management. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Structure, production and properties of high-melting compounds and systems (hard materials and hard metals)

    International Nuclear Information System (INIS)

    Holleck, H.; Thuemmler, F.

    1979-07-01

    The report contains contributions by various authors to the research project on the production, structure, and physical properties of high-melting compounds and systems (hard metals and hard materials), in particular WC-, TaC-, and MoC-base materials. (GSCH) [de

  9. Do constructed wetlands remove metals or increase metal bioavailability?

    Science.gov (United States)

    Xu, Xiaoyu; Mills, Gary L

    2018-07-15

    The H-02 wetland was constructed to treat building process water and storm runoff water from the Tritium Processing Facility on the Department of Energy's Savannah River Site (Aiken, SC). Monthly monitoring of copper (Cu) and zinc (Zn) concentrations and water quality parameters in surface waters continued from 2014 to 2016. Metal speciation was modeled at each sampling occasion. Total Cu and Zn concentrations released to the effluent stream were below the NPDES limit, and the average removal efficiency was 65.9% for Cu and 71.1% for Zn. The metal-removal processes were found out to be seasonally regulated by sulfur cycling indicated by laboratory and model results. High temperature, adequate labile organic matter, and anaerobic conditions during the warm months (February to August) favored sulfate reduction that produced sulfide minerals to significantly remove metals. However, the dominant reaction in sulfur cycling shifted to sulfide oxidation during the cool months (September to next March). High concentrations of metal-organic complexes were observed, especially colloidal complexes of metal and fulvic acid (FA), demonstrating adsorption to organic matter became the primary process for metal removal. Meanwhile, the accumulation of metal-FA complexes in the wetland system will cause negative effects to the surrounding environment as they are biologically reactive, highly bioavailable, and can be easily taken up and transferred to ecosystems by trophic exchange. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. ‘… a metal conducts and a non-metal doesn't’

    Science.gov (United States)

    Edwards, P. P.; Lodge, M. T. J.; Hensel, F.; Redmer, R.

    2010-01-01

    In a letter to one of the authors, Sir Nevill Mott, then in his tenth decade, highlighted the fact that the statement ‘… a metal conducts, and a non-metal doesn’t’ can be true only at the absolute zero of temperature, T=0 K. But, of course, experimental studies of metals, non-metals and, indeed, the electronic and thermodynamic transition between these canonical states of matter must always occur above T=0 K, and, in many important cases, for temperatures far above the absolute zero. Here, we review the issues—theoretical and experimental—attendant on studies of the metal to non-metal transition in doped semiconductors at temperatures close to absolute zero (T=0.03 K) and fluid chemical elements at temperatures far above absolute zero (T>1000 K). We attempt to illustrate Mott’s insights for delving into such complex phenomena and experimental systems, finding intuitively the dominant features of the science, and developing a coherent picture of the different competing electronic processes. A particular emphasis is placed on the idea of a ‘Mott metal to non-metal transition’ in the nominally metallic chemical elements rubidium, caesium and mercury, and the converse metallization transition in the nominally non-metal elements hydrogen and oxygen. We also review major innovations by D. A. Goldhammer (Goldhammer 1913 Dispersion und absorption des lichtes) and K. F. Herzfeld (Herzfeld 1927 Phys. Rev. 29, 701–705. (doi:10.1103/PhysRev.29.701)) in a pre-quantum theory description of the metal–non-metal transition, which emphasize the pivotal role of atomic properties in dictating the metallic or non-metallic status of the chemical elements of the periodic table under ambient and extreme conditions; a link with Pauling’s ‘metallic orbital’ is also established here. PMID:20123742

  11. Development and Validation of a Biodynamic Model for Mechanistically Predicting Metal Accumulation in Fish-Parasite Systems.

    Directory of Open Access Journals (Sweden)

    T T Yen Le

    Full Text Available Because of different reported effects of parasitism on the accumulation of metals in fish, it is important to consider parasites while interpreting bioaccumulation data from biomonitoring programmes. Accordingly, the first step is to take parasitism into consideration when simulating metal bioaccumulation in the fish host under laboratory conditions. In the present study, the accumulation of metals in fish-parasite systems was simulated by a one-compartment toxicokinetic model and compared to uninfected conspecifics. As such, metal accumulation in fish was assumed to result from a balance of different uptake and loss processes depending on the infection status. The uptake by parasites was considered an efflux from the fish host, similar to elimination. Physiological rate constants for the uninfected fish were parameterised based on the covalent index and the species weight while the parameterisation for the infected fish was carried out based on the reported effects of parasites on the uptake kinetics of the fish host. The model was then validated for the system of the chub Squalius cephalus and the acanthocephalan Pomphorhynchus tereticollis following 36-day exposure to waterborne Pb. The dissolved concentration of Pb in the exposure tank water fluctuated during the exposure, ranging from 40 to 120 μg/L. Generally, the present study shows that the one-compartment model can be an effective method for simulating the accumulation of metals in fish, taking into account effects of parasitism. In particular, the predicted concentrations of Cu, Fe, Zn, and Pb in the uninfected chub as well as in the infected chub and the acanthocephalans were within one order of magnitude of the measurements. The variation in the absorption efficiency and the elimination rate constant of the uninfected chub resulted in variations of about one order of magnitude in the predicted concentrations of Pb. Inclusion of further assumptions for simulating metal accumulation

  12. A STUDY OF LEAKAGE OF TRACE METALS FROM CORROSION OF THE MUNICIPAL DRINKING WATER DISTRIBUTION SYSTEM

    Directory of Open Access Journals (Sweden)

    M.R SHA MANSOURI

    2003-09-01

    Full Text Available Introduction: A high portion of lead and copper concentration in municipal drinking water is related to the metallic structure of the distribution system and facets. The corrosive water in pipes and facets cause dissolution of the metals such as Pb, Cu, Cd, Zn, Fe and Mn into the water. Due to the lack of research work in this area, a study of the trace metals were performed in the drinking water distribution system in Zarin Shahr and Mobareke of Isfahan province. Methods: Based on the united states Environmental protection Agency (USEPA for the cities over than 50,000 population such as Zarin Shahr and Mobareke, 30 water samples from home facets with the minimum 6 hours retention time of water in pipes, were collected. Lead and cadmium concentration were determined using flameless Atomic Absorption. Cupper, Zinc, Iron and Manganese were determined using Atomic Absorption. Results: The average concentration of Pb, Cd, Zn, Fe and Mn in water distribution system fo Zarin Shahr were 5.7, 0.1, 80, 3042, 23065 and in Mobareke were 7.83, 0.8,210,3100, 253, 17µg respectively. The cocentration of Pb, Cd and Zn were zero at the beginning of the water samples from the municipal drinking water distribution system for both cities. Conclusion: The study showed that the corrosion by products (such as Pb, Cd and Zn was the results of dissolution of the galvanized pipes and brass facets. Lead concentration in over that 10 percent of the water samples in zarin shahr exceeded the drinking water standard level, which emphasize the evaluation and control of corrosion in drinking water distribution systems.

  13. Corrosion resistant amorphous metals and methods of forming corrosion resistant amorphous metals

    Science.gov (United States)

    Farmer, Joseph C [Tracy, CA; Wong, Frank M. G. [Livermore, CA; Haslam, Jeffery J [Livermore, CA; Yang, Nancy [Lafayette, CA; Lavernia, Enrique J [Davis, CA; Blue, Craig A [Knoxville, TN; Graeve, Olivia A [Reno, NV; Bayles, Robert [Annandale, VA; Perepezko, John H [Madison, WI; Kaufman, Larry [Brookline, MA; Schoenung, Julie [Davis, CA; Ajdelsztajn, Leo [Walnut Creek, CA

    2009-11-17

    A system for coating a surface comprises providing a source of amorphous metal, providing ceramic particles, and applying the amorphous metal and the ceramic particles to the surface by a spray. The coating comprises a composite material made of amorphous metal that contains one or more of the following elements in the specified range of composition: yttrium (.gtoreq.1 atomic %), chromium (14 to 18 atomic %), molybdenum (.gtoreq.7 atomic %), tungsten (.gtoreq.1 atomic %), boron (.ltoreq.5 atomic %), or carbon (.gtoreq.4 atomic %).

  14. The Mean Metal-line Absorption Spectrum of Damped Ly α Systems in BOSS

    Energy Technology Data Exchange (ETDEWEB)

    Mas-Ribas, Lluís [Institute of Theoretical Astrophysics, University of Oslo, Postboks 1029, NO-0315 Oslo (Norway); Miralda-Escudé, Jordi; Pérez-Ràfols, Ignasi; Arinyo-i-Prats, Andreu [Institut de Ciències del Cosmos, Universitat de Barcelona (UB-IEEC), Barcelona E-08028, Catalonia (Spain); Noterdaeme, Pasquier; Petitjean, Patrick [Institut d’Astrophysique de Paris, UPMC and CNRS, UMR7095 98bis Boulevard Arago, F-75014—Paris (France); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); York, Donald G. [Department of Astronomy and Astrophysics and the Enrico Fermi Institute, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Ge, Jian, E-mail: l.m.ribas@astro.uio.no [Department of Astronomy, University of Florida, Bryant Space Science Center, Gainesville, FL 32611-2055 (United States)

    2017-09-01

    We study the mean absorption spectrum of the Damped Ly α (DLA) population at z ∼ 2.6 by stacking normalized, rest-frame-shifted spectra of ∼27,000 DLA systems from the DR12 of the Baryon Oscillation Spectroscopic Survey (BOSS)/SDSS-III. We measure the equivalent widths of 50 individual metal absorption lines in five intervals of DLA hydrogen column density, five intervals of DLA redshift, and overall mean equivalent widths for an additional 13 absorption features from groups of strongly blended lines. The mean equivalent width of low-ionization lines increases with N {sub H} {sub i}, whereas for high-ionization lines the increase is much weaker. The mean metal line equivalent widths decrease by a factor ∼1.1–1.5 from z ∼ 2.1 to z ∼ 3.5, with small or no differences between low- and high-ionization species. We develop a theoretical model, inspired by the presence of multiple absorption components observed in high-resolution spectra, to infer mean metal column densities from the equivalent widths of partially saturated metal lines. We apply this model to 14 low-ionization species and to Al iii, S iii, Si iii, C iv, Si iv, N v, and O vi. We use an approximate derivation for separating the equivalent width contributions of several lines to blended absorption features, and infer mean equivalent widths and column densities from lines of the additional species N i, Zn ii, C ii*, Fe iii, and S iv. Several of these mean column densities of metal lines in DLAs are obtained for the first time; their values generally agree with measurements of individual DLAs from high-resolution, high signal-to-noise ratio spectra when they are available.

  15. Shear bond strength and debonding characteristics of metal and ceramic brackets bonded with conventional acid-etch and self-etch primer systems: An in-vivo study.

    Science.gov (United States)

    Mirzakouchaki, Behnam; Shirazi, Sajjad; Sharghi, Reza; Shirazi, Samaneh; Moghimi, Mahsan; Shahrbaf, Shirin

    2016-02-01

    Different in-vitro studies have reported various results regarding shear bond strength (SBS) of orthodontic brackets when SEP technique is compared to conventional system. This in-vivo study was designed to compare the effect of conventional acid-etching and self-etching primer adhesive (SEP) systems on SBS and debonding characteristics of metal and ceramic orthodontic brackets. 120 intact first maxillary and mandibular premolars of 30 orthodontic patients were selected and bonded with metal and ceramic brackets using conventional acid-etch or self-etch primer system. The bonded brackets were incorporated into the wire during the study period to simulate the real orthodontic treatment condition. The teeth were extracted and debonded after 30 days. The SBS, debonding characteristics and adhesive remnant indices (ARI) were determined in all groups. The mean SBS of metal brackets was 10.63±1.42 MPa in conventional and 9.38±1.53 MPa in SEP system, (P=0.004). No statistically significant difference was noted between conventional and SEP systems in ceramic brackets. The frequency of 1, 2 and 3 ARI scores and debonding within the adhesive were the most common among all groups. No statistically significant difference was observed regarding ARI or failure mode of debonded specimens in different brackets or bonding systems. The SBS of metal brackets bonded using conventional system was significantly higher than SEP system, although the SBS of SEP system was clinically acceptable. No significant difference was found between conventional and SEP systems used with ceramic brackets. Total SBS of metal brackets was significantly higher than ceramic brackets. Due to adequate SBS of SEP system in bonding the metal brackets, it can be used as an alternative for conventional system. Shear bond strength, Orthodontic brackets, Adhesive remnant index, self-etch.

  16. Geochemical modelling and speciation studies of metal pollutants present in selected water systems in South Africa

    Science.gov (United States)

    Magu, M. M.; Govender, P. P.; Ngila, J. C.

    2016-04-01

    Metal pollutants in water poses great threats to living beings and hence requires to be monitored regularly to avoid loss of lives. Various analytical methods are available to monitor these pollutants in water and can be improved with time. Modelling of metal pollutants in any water system helps chemists, engineers and environmentalists to greatly understand the various chemical processes in such systems. Water samples were collected from waste water treatment plant and river from highlands close to its source all the way to the ocean as it passing through areas with high anthropogenic activities. Pre-concentration of pollutants in the samples was done through acid digestion and metal pollutants were analysed using inductively coupled plasma-optical emission spectra (ICP-OES) to determine the concentration levels. Metal concentrations ranged between 0.1356-0.4658 mg/L for Al; 0.0031-0.0050 mg/L for Co, 0.0019-0.0956 mg/L for Cr; 0.0028-0.3484 mg/L for Cu; 0.0489-0.3474 mg/L for Fe; 0.0033-0.0285 mg/L for Mn; 0.0056-0.0222 mg/L for Ni; 0.0265-0.4753 mg/L for Pb and 0.0052-0.5594 mg/L for Zn. Modelling work was performed using PHREEQC couple with Geochemist's workbench (GWB) to determine speciation dynamics and bioavailability of these pollutants. Modelling thus adds value to analytical methods and hence a better complementary tool to laboratory-based experimental studies.

  17. Development of a heavy metal sorption system through the P=S functionalization of coconut (Cocos nucifera) fibers.

    Science.gov (United States)

    de Sousa, Dayane Almeida; de Oliveira, Elisabeth; da Costa Nogueira, Márcio; Espósito, Breno Pannia

    2010-01-01

    Lignocellulosic residues are interesting materials for the production of heavy metal adsorbents for aquatic systems. Whole fibers taken from coconut (Cocos nucifera) husks were functionalized with the thiophosphoryl (P=S) group by means of the direct reaction with Cl(3)PS, (CH(3)O)(2)ClP=S or (CH(3)CH(2)O)(2)ClP=S in order to obtain an adsorptive system for 'soft' metal ions, particularly Cd(2+). These functionalized fibers (FFs) were characterized by means of elemental analysis, infrared spectroscopy, thermal analysis and acid-base titration. Adsorption isotherms for Cd(2+) fitted the Langmuir model, with binding capacities of 0.2-5 m mol g(-1) of FF at 25 degrees C.

  18. Advances in liquid metal cooled ADS systems, and useful results for the design of IFMIF

    International Nuclear Information System (INIS)

    Massaut, V.; Debruyn, D.; Decreton, M.

    2007-01-01

    Full text of publication follows: Liquid metal cooled Accelerator Driven Systems (ADS) have a lot of design commonalities with the design of IFMIF. The use of a powerful accelerator and a liquid metal spallation source makes it similar to the main features of the IFMIF irradiator. Developments in the field of liquid metal ADS can thus be very useful for the design phase of IFMIF, and synergy between both domains should be enhanced to avoid dubbing work already done. The liquid metal ADS facilities are developed for testing materials under high fast (> 1 MeV) neutron flux, and also for studying the transmutation of actinides as foreseen in the P and T (Partitioning and Transmutation) strategy of future fission industry. The ADS are mostly constituted of a sub-critical fission fuel assembly matrix, a spallation source (situated at the centre of the fuel arrangement) and a powerful accelerator targeting the spallation source. In liquid metal ADS, the spallation source is a liquid metal (like Pb-Bi) which is actively cooled to remove the power generated by the particle beam, spallation reactions and neutrons. Based on an advanced ADS design (e.g. the MYRRHA/XT-ADS facility), the paper shows the various topics which are common for both facilities (ADS and IFMIF) and highlights their respective specificities, leading to focused R and D activities. This would certainly cover the common aspects related to high power accelerators, liquid metal targets and beam-target coupling. But problems of safety, radioprotection, source heating and cooling, neutrons shielding, etc... lead also to common features and developments. Results already obtained for the ADS development will illustrate this synergy. This paper will therefore allow to take profit of recent developments in both fission and fusion programs and enhance the collaboration among the R and D teams in both domains. (authors)

  19. Advances in liquid metal cooled ADS systems, and useful results for the design of IFMIF

    Energy Technology Data Exchange (ETDEWEB)

    Massaut, V.; Debruyn, D. [SCK CEN, Mol (Belgium); Decreton, M. [Ghent Univ., Dept. of Applied Physics (Belgium)

    2007-07-01

    Full text of publication follows: Liquid metal cooled Accelerator Driven Systems (ADS) have a lot of design commonalities with the design of IFMIF. The use of a powerful accelerator and a liquid metal spallation source makes it similar to the main features of the IFMIF irradiator. Developments in the field of liquid metal ADS can thus be very useful for the design phase of IFMIF, and synergy between both domains should be enhanced to avoid dubbing work already done. The liquid metal ADS facilities are developed for testing materials under high fast (> 1 MeV) neutron flux, and also for studying the transmutation of actinides as foreseen in the P and T (Partitioning and Transmutation) strategy of future fission industry. The ADS are mostly constituted of a sub-critical fission fuel assembly matrix, a spallation source (situated at the centre of the fuel arrangement) and a powerful accelerator targeting the spallation source. In liquid metal ADS, the spallation source is a liquid metal (like Pb-Bi) which is actively cooled to remove the power generated by the particle beam, spallation reactions and neutrons. Based on an advanced ADS design (e.g. the MYRRHA/XT-ADS facility), the paper shows the various topics which are common for both facilities (ADS and IFMIF) and highlights their respective specificities, leading to focused R and D activities. This would certainly cover the common aspects related to high power accelerators, liquid metal targets and beam-target coupling. But problems of safety, radioprotection, source heating and cooling, neutrons shielding, etc... lead also to common features and developments. Results already obtained for the ADS development will illustrate this synergy. This paper will therefore allow to take profit of recent developments in both fission and fusion programs and enhance the collaboration among the R and D teams in both domains. (authors)

  20. Metal-binding silica materials for wastewater cleanup

    Energy Technology Data Exchange (ETDEWEB)

    Kroh, F.O. [TPL, Inc., Albuquerque, NM (United States)

    1997-10-01

    In this Phase I Small Business Innovation Research program, TPL, Inc. is developing two series of high-efficiency covalently modified silica materials for removing heavy metal ions from wastewater. These materials have metal ion capacities greatly exceeding those of commercial ion exchange resins. One series, containing thiol groups, has high capacity for {open_quotes}soft{close_quotes} heavy metal ions such as Hg, Pb, Ag, and Cd; the other, containing quaternary ammonium groups, has high capacity for anionic metal ions such as pertechnetate, arsenate, selenite, and chromate. These materials have high selectivity for the contaminant metals and will function well in harsh systems that inactivate other systems.

  1. Carbothermic reduction of refractory metals

    International Nuclear Information System (INIS)

    Anderson, R.N.; Parlee, N.A.D.

    1976-01-01

    The reduction of stable refractory metal oxides by carbon is generally unacceptable since the product is usually contaminated with carbides. The carbide formation may be avoided by selecting a solvent metal to dissolve the reactive metal as it is produced and reduce its chemical activity below that required for carbide formation. This approach has been successfully applied to the oxides of Si, Zr, Ti, Al, Mg, and U. In the case where a volatile suboxide, a carbonyl reaction, or a volatile metal occur, the use of the solvent metal appears satisfactory to limit the loss of material at low pressures. In several solute--solvent systems, vacuum evaporation is used to strip the solvent metal from the alloy to give the pure metal

  2. Overview of liquid-metal MHD

    International Nuclear Information System (INIS)

    Dunn, P.F.

    1978-01-01

    The basic features of the two-phase liquid-metal MHD energy conversion under development at Argonne National Laboratory are presented. The results of system studies on the Rankine-cycle and the open-cycle coal-fired cycle options are discussed. The liquid-metal MHD experimental facilities are described in addition to the system's major components, the generator, mixer and nozzle-separator-diffuser

  3. Structural and functional effects of heavy metals on the nervous system, including sense organs, of fish

    DEFF Research Database (Denmark)

    Baatrup, E

    1991-01-01

    metals are well known pollutants in the aquatic environment. Their interaction with relevant chemical stimuli may interfere with the communication between fish and environment. 5. The affinity for a number of ligands and macromolecules makes heavy metals most potent neurotoxins. 6. The present Mini......1. Today, fish in the environment are inevitably exposed to chemical pollution. Although most hazardous substances are present at concentrations far below the lethal level, they may still cause serious damage to the life processes of these animals. 2. Fish depend on an intact nervous system......, including their sense organs, for mediating relevant behaviour such as food search, predator recognition, communication and orientation. 3. Unfortunately, the nervous system is most vulnerable and injuries to its elements may dramatically change the behaviour and consequently the survival of fish. 4. Heavy...

  4. Time domain electromagnetic metal detectors

    International Nuclear Information System (INIS)

    Hoekstra, P.

    1996-01-01

    This presentation focuses on illustrating by case histories the range of applications and limitations of time domain electromagnetic (TDEM) systems for buried metal detection. Advantages claimed for TDEM metal detectors are: independent of instrument response (Geonics EM61) to surrounding soil and rock type; simple anomaly shape; mitigation of interference by ambient electromagnetic noise; and responsive to both ferrous and non-ferrous metallic targets. The data in all case histories to be presented were acquired with the Geonics EM61 TDEM system. Case histories are a test bed site on Molokai, Hawaii; Fort Monroe, Virginia; and USDOE, Rocky Flats Plant. The present limitations of this technology are: discrimination capabilities in terms of type of ordnance, and depth of burial is limited, and ability of resolving targets with small metallic ambient needs to be improved

  5. Temporal variations and spatial distributions of heavy metals in a wastewater-irrigated soil-eggplant system and associated influencing factors.

    Science.gov (United States)

    Ai, Shiwei; Liu, Bailin; Yang, Ying; Ding, Jian; Yang, Wenzhi; Bai, Xiaojuan; Naeem, Sajid; Zhang, Yingmei

    2018-05-30

    Heavy metal pollution in farmlands is highly concerned as crops' easy-uptake of heavy metal can ultimately affect consumers. In order to offer suggestions on cultivating safe quality vegetable, specifically eggplant which is widely consumed for its nutritional value and antioxidant activity, a field study was undertaken to investigate the temporal variations and spatial distributions of heavy metals in a wastewater-irrigated soil-eggplant system. In the present study, eggplants were planted in the farmlands of Weichuan village (WC) (relatively unpolluted field), Liangzhuang village (LZ) (moderately polluted field) and Minqin village (MQ) (seriously polluted field) to elucidate their temporal uptake processes of heavy metals described by the sigmoid model. Eggplant tissues from severely polluted farmlands were found with higher heavy metal concentrations and lower yields compared with other two groups. What is more, 25 farmlands along the Dongdagou stream (heavy metals polluted stream) were chosen to analyze the spatial distribution of heavy metals in soils and eggplants. Heavy metal concentrations in eggplants decreased with the decline of heavy metal concentrations in soil from upstream (pollution source) to downstream. Moreover, several methods were employed to assess bioavailability of heavy metals in soils. All the bioavailable heavy metals were found in linear positive correlations with heavy metal concentrations. Meanwhile, linear correlations were found between heavy metals in soils and eggplants. At last, redundancy analysis was used to investigate the effects of soil properties (pH, organic matter and texture of soils) and heavy metals on eggplants' uptake. The results indicated that soil heavy metals had a dominant impact on their accumulations in eggplant fruit, with a variance contribution of 78.0%, while soil properties had a regulatory effect, with a variance contribution of 5.2%. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. Friction and metal transfer for single-crystal silicon carbide in contact with various metals in vacuum

    International Nuclear Information System (INIS)

    Miyoshi, K.; Buckley, D.H.

    1978-04-01

    Sliding friction experiments were conducted with single-crystal silicon carbide in contact with transition metals (tungsten, iron, rhodium, nickel, titanium, and cobalt), copper, and aluminum. Results indicate the coefficient of friction for a silicon carbide-metal system is related to the d bond character and relative chemical activity of the metal. The more active the metal, the higher the coefficient of friction. All the metals examined transferred to the surface of silicon carbide in sliding. The chemical activity of metal to silicon and carbon and shear modulus of the metal may play important roles in metal transfer and the form of the wear debris. The less active metal is, and the greater resistance to shear it has, with the exception of rhodium and tungsten, the less transfer to silicon carbide

  7. Accuracy evaluation of metal copings fabricated by computer-aided milling and direct metal laser sintering systems.

    Science.gov (United States)

    Park, Jong-Kyoung; Lee, Wan-Sun; Kim, Hae-Young; Kim, Woong-Chul; Kim, Ji-Hwan

    2015-04-01

    To assess the marginal and internal gaps of the copings fabricated by computer-aided milling and direct metal laser sintering (DMLS) systems in comparison to casting method. Ten metal copings were fabricated by casting, computer-aided milling, and DMLS. Seven mesiodistal and labiolingual positions were then measured, and each of these were divided into the categories; marginal gap (MG), cervical gap (CG), axial wall at internal gap (AG), and incisal edge at internal gap (IG). Evaluation was performed by a silicone replica technique. A digital microscope was used for measurement of silicone layer. Statistical analyses included one-way and repeated measure ANOVA to test the difference between the fabrication methods and categories of measured points (α=.05), respectively. The mean gap differed significantly with fabrication methods (P<.001). Casting produced the narrowest gap in each of the four measured positions, whereas CG, AG, and IG proved narrower in computer-aided milling than in DMLS. Thus, with the exception of MG, all positions exhibited a significant difference between computer-aided milling and DMLS (P<.05). Although the gap was found to vary with fabrication methods, the marginal and internal gaps of the copings fabricated by computer-aided milling and DMLS fell within the range of clinical acceptance (<120 µm). However, the statistically significant difference to conventional casting indicates that the gaps in computer-aided milling and DMLS fabricated restorations still need to be further reduced.

  8. Release of metal ions from fixed orthodontic appliance: an in vitro study in continuous flow system.

    Science.gov (United States)

    Mikulewicz, Marcin; Chojnacka, Katarzyna; Wołowiec, Paulina

    2014-01-01

    To evaluate the release of metal ions from fixed orthodontic appliances. A new system for in vitro testing of dental materials was constructed and consisted of a thermostatic glass reactor that enabled immersion of the studied material. Experimental conditions reflected the human oral cavity, with a temperature of 37°C and a saliva flow rate of 0.5mL/min. The simulated fixed orthodontic appliance made of stainless steel was evaluated. Sampling was performed at several time points during the 28-day study, and the metal ion concentration was determined by inductively coupled plasma optical emission spectrometry. The total mass of released metal ions from the appliance during 4 weeks of the experiment was as follows nickel 18.7 μg, chromium 5.47 μg, copper 31.3 μg. The estimated doses of nickel, chromium, and copper determined by extrapolation of experimental data released during the treatment period were far below the toxic dose to humans. This shows that orthodontic treatment might not be a significant source of exposure to these metal ions.

  9. Design, fabrication, and application of a directional thermal processing system for controlled devitrification of metallic glasses

    Science.gov (United States)

    Meyer, Megan Anne Lamb

    The potential of using metallic glass as a pathway to obtaining novel morphologies and metastable phases has been garnering attention since their discovery. Several rapid solidification techniques; such as gas atomization, melt spinning, laser melting, and splat quenching produce amorphous alloys. A directional thermal processing system (DTPS) was designed, fabricated and characterized for the use of zone processing or gradient-zone processing of materials. Melt-spun CuZr metallic glass alloy was subjected to the DTPS and the relaxation and crystallization responses of the metallic glass were characterized. A range of processing parameters were developed and analyzed that would allow for devitrification to occur. The relaxation and crystallization responses were compared with traditional heat treatment methods of metallic glasses. The new processing method accessed equilibrium and non-equilibrium phases of the alloy and the structures were found to be controllable and sensitive to processing conditions. Crystallized fraction, crystallization onset temperature, and structural relaxation were controlled through adjusting the processing conditions, such as the hot zone temperature and sample velocity. Reaction rates computed from isothermal (TTT) transformation data were not found to be reliable, suggesting that the reaction kinetics are not additive. This new processing method allows for future studying of the thermal history effects of metallic glasses.

  10. Study on liquid-metal MHD power generation system with two-phase natural circulation. Applicability to fast reactor conditions

    International Nuclear Information System (INIS)

    Saito, Masaki

    2001-03-01

    Feasibility study of the liquid-metal MHD power generation system combined with the high-density two-phase natural circulation has been performed for the applicability to the simple, autonomic energy conversion system of the liquid-metal cooled fast reactor. The present system has many promising aspects not only in the energy conversion process, but also in safety and economical improvements of the liquid-metal cooled fast reactor. In the previous report, as the first step of the feasibility study, the cycle analyses were performed to examine the effects of the main system parameters on the fundamental characteristics of the system. It was found that the cycle efficiency of the present system is enough competitive with that of the conventional steam turbine system. It was also found that the cycle efficiency depends strongly on the gas-liquid slip ratio in the two-phase flow channel. However, it is very difficult to estimate the gas-liquid slip ratio theoretically, especially in the heavy liquid metal two-phase natural circulation. For example, the effects of MHD load on the two-phase flow characteristics, such as the void fraction and gas-liquid slip ratio are not known well. In the present study, therefore, as the second step of the feasibility study, a series of the experiments were performed to investigate, especially, the effect of MHD load at the single-phase shown-comer flow channel on the characteristics of the two-phase natural circulation. In the first series of the experiments, Woods-metal (Density: 9517 Kg/m 3 ) and nitrogen gas were chosen as the two-phase working fluids. The MHD pressure drop was simulated by the ball valve. The experiments with water and nitrogen gas were also performed to check the effects of the physical properties. From the present experiments, it is found that the average void fraction in the two-phase flow channel is determined by the force balance between the MHD pressure drop, frictional and pressure losses in the tube, and

  11. Heavy metal removal from water/wastewater by nanosized metal oxides: A review

    International Nuclear Information System (INIS)

    Hua, Ming; Zhang, Shujuan; Pan, Bingcai; Zhang, Weiming; Lv, Lu; Zhang, Quanxing

    2012-01-01

    Nanosized metal oxides (NMOs), including nanosized ferric oxides, manganese oxides, aluminum oxides, titanium oxides, magnesium oxides and cerium oxides, provide high surface area and specific affinity for heavy metal adsorption from aqueous systems. To date, it has become a hot topic to develop new technologies to synthesize NMOs, to evaluate their removal of heavy metals under varying experimental conditions, to reveal the underlying mechanism responsible for metal removal based on modern analytical techniques (XAS, ATR-FT-IR, NMR, etc.) or mathematical models, and to develop metal oxide-based materials of better applicability for practical use (such as granular oxides or composite materials). The present review mainly focuses on NMOs’ preparation, their physicochemical properties, adsorption characteristics and mechanism, as well as their application in heavy metal removal. In addition, porous host supported NMOs are particularly concerned because of their great advantages for practical application as compared to the original NMOs. Also, some magnetic NMOs were included due to their unique separation performance.

  12. Impact of experimentation in thermodynamic studies of some metallic and oxidic systems

    Directory of Open Access Journals (Sweden)

    Aune R.E.

    2002-01-01

    Full Text Available The importance of experimentation as an ingredient to CALPHAD assessments is brought out in the present paper and is illustrated in the case of a number of metallic and oxidic systems. Two types of experimental techniques have been used in the present laboratory for thermodynamic studies, and the details are presented. The results obtained together with the assessed phase diagram in the case of a few selected systems are presented. It was shown that careful experimentation has brought new features in the case of carbide systems involving Mn, and a new 4-phase equilibrium in the case of Ni-W-O system. New data with regard to the thermodynamic activities of FeO-containing slag systems and sulphide capacities of multicomponent slags, obtained by gas equilibration method, are also presented. A thermodynamic software, THERMOSLAG© based on the experimental data has been found to be extremely useful by the steel industries is also discussed.

  13. Predicting Metal Speciation & Bioavailability via Estimation of Metal-Organic Thermodynamic Properties

    Science.gov (United States)

    Prasad, A.; Howells, A. E.; Shock, E.

    2017-12-01

    The biological fate of any metal depends on its chemical form in the environment. Arsenic for example, is extremely toxic in the form of inorganic As+3 but completely benign in the organic form of arsenobetaine. Thus, given an exhaustive set of reactions and their equilibrium constants (logK), the bioavailability of any metal can be obtained for blood plasma, hydrothermal fluids or any system of interest. While many data exist for metal-inorganic ligands, logK data covering the temperature range of life for metal-organic complexes are sparse. Hence, we decided to estimate metal-organic logK values from correlations with the commonly available values of ligand pKa. Metal ion specific correlations were made with ligands classified according to their electron donor atoms, denticity and other chemical factors. While this approach has been employed before (Carbonaro et al. 2007, GCA 71, 3958-3968), new correlations were developed that provide estimates even when no metal-organic logK is available. In addition, we have used the same methods to make estimates of metal-organic entropy of association (ΔaS), which can provide logK for any temperature of biological relevance. Our current correlations employ logK and ΔaS data from 30 metal ions (like the biologically relevant Fe+3 & Zn+2) and 74 ligands (like formate and ethylenediamine), which can be expanded to estimate the metal-ligand reaction properties for these 30 metal ions with a possibly limitless number of ligands that may belong to our categories of ligands. With the help of such data, copper speciation was obtained for a defined growth medium for methanotrophs employed by Morton et al. (2000, AEM 66, 1730-1733) that agrees with experimental measurements showing that the free metal ion may not be the bioavailable form in all conditions. These results encourage us to keep filling the gaps in metal-organic logK data and continue finding relationships between biological responses (like metal-accumulation ratios

  14. Chromatography of 49 metal ions on stannic antimonate papers in dimethylsulfoxide: nitric acid systems and aqueous nitric acid systems

    International Nuclear Information System (INIS)

    Qureshi, M.; Varshney, K.G.; Rajput, R.P.S.

    1975-01-01

    Chromatographic separations of 49 metal ions on stannic antimonate papers have been performed using mixed solvent systems containing DMSO. Aqueous HNO 3 systems have also been used. The utility of the papers has been demonstrated by achieving various difficult separations. Some of the important separations (R/sub f/ values given in parentheses) are: Cs + (0.20)-K + (0.30) and Sm 3+ (0.00)-Pr 3+ (0.72) in pure DMSO; Nb 5+ (0.14)-VO 2+ (0.95) in DMSO-6M HNO 3 (1:1); Ti 4+ (0.00)-VO 2 (0.97) in DMSO-0.5M HNO 3 (1:1); and Ba 2+ (0.06)-K + (0.52)-Sr 2+ (0.95), Ba 2+ (0.04)-Cs + (0.41)-Mg 2+ (0.93), and Ca 2+ (0.10)-Sr 2+ (0.94) in DMSO-0.1M HNO 3 (1:1). The time of development in each case is two hours. A discussion is presented on the dependence of Ri, log R/sub f/, and R/sub M/ on pH of the solvent to understand the mechanism of the movement of metal ions on papers impregnated with inorganic materials. (U.S.)

  15. Comparison of Some Rural Wastewater Refining Systems Considering Chemical Properties and Heavy Metals

    Directory of Open Access Journals (Sweden)

    Najme Yazdanpanah

    2016-02-01

    Full Text Available Introduction: Water scarcity is an important challenge worldwide, especially in arid and semi-arid regions. In these areas, the excessive exploitation of groundwater for irrigation, inefficient irrigation methods, irrigation with low-quality water and uncontrolled utilization of fertilizers in agricultural lands in addition to contamination of water resources by domestic and industrial wastewater in urban as well as rural regions, have led to water pollution problems. Furthermore, pollution and transportation of pollutants through wastewater have been considered as an environmental issue. Wastewater is a term that is used to describe waste materials that includes liquid waste and sewage waste. Wastewaters from single houses in the countryside that are not connected to sewers are generally treated on-site by septic tank systems or individual domestic wastewater treatment systems. Study on wastewater quality derived from refining systems in rural areas has been rarely taken into account. This study investigates the efficiency of some refining systems in the reduction of wastewater pollution indices and heavy metal concentrations. Materials and Methods: This study was done in four rural areas including Dehmilan, Hotkan, Sarbagh and Sekukan which are located around the city of Zarand in the Kerman province. Recently, some refining systems have been established in these areas in order to mitigate the environmental issues. An experiment was done to assess the efficiency of these refining systems and to determine the pollution indices for such small communities. Wastewater sampling was done in 10 replicates each at one week interval from four refineries. Different variables including BOD, COD, TOC, EC, TSS, TDS, DO, TKN, TP, pH, temperature, turbidity (Turb, alkanity (Alk and also the concentrations of Cd, Zn, Pb, Ni and Mo were measured using standard methods. To quantify the performance of each system, the amount of each variable at the outlet was

  16. Assessment of heavy metals exposure, noise and thermal safety in the ambiance of a vacuum metallurgy separation system for recycling heavy metals from crushed e-wastes.

    Science.gov (United States)

    Zhan, Lu; Xu, Zhenming

    2014-12-01

    Vacuum metallurgy separation (VMS) is a technically feasible method to recover Pb, Cd and other heavy metals from crushed e-wastes. To further determine the environmental impacts and safety of this method, heavy metals exposure, noise and thermal safety in the ambiance of a vacuum metallurgy separation system are evaluated in this article. The mass concentrations of total suspended particulate (TSP) and PM10 are 0.1503 and 0.0973 mg m(-3) near the facilities. The concentrations of Pb, Cd and Sn in TSP samples are 0.0104, 0.1283 and 0.0961 μg m(-3), respectively. Health risk assessments show that the hazard index of Pb is 3.25 × 10(-1) and that of Cd is 1.09 × 10(-1). Carcinogenic risk of Cd through inhalation is 1.08 × 10(-5). The values of the hazard index and risk indicate that Pb and Cd will not cause non-cancerous effects or carcinogenic risk on workers. The noise sources are mainly the mechanical vacuum pump and the water cooling pump. Both of them have the noise levels below 80 dB (A). The thermal safety assessment shows that the temperatures of the vacuum metallurgy separation system surface are all below 303 K after adopting the circulated water cooling and heat insulation measures. This study provides the environmental information of the vacuum metallurgy separation system, which is of assistance to promote the industrialisation of vacuum metallurgy separation for recovering heavy metals from e-wastes. © The Author(s) 2014.

  17. Metallic photonic band-gap materials

    International Nuclear Information System (INIS)

    Sigalas, M.M.; Chan, C.T.; Ho, K.M.; Soukoulis, C.M.

    1995-01-01

    We calculate the transmission and absorption of electromagnetic waves propagating in two-dimensional (2D) and 3D periodic metallic photonic band-gap (PBG) structures. For 2D systems, there is substantial difference between the s- and p-polarized waves. The p-polarized waves exhibit behavior similar to the dielectric PBG's. But, the s-polarized waves have a cutoff frequency below which there are no propagating modes. For 3D systems, the results are qualitatively the same for both polarizations but there are important differences related to the topology of the structure. For 3D structures with isolated metallic scatterers (cermet topology), the behavior is similar to that of the dielectric PBG's, while for 3D structures with the metal forming a continuous network (network topology), there is a cutoff frequency below which there are no propagating modes. The systems with the network topology may have some interesting applications for frequencies less than about 1 THz where the absorption can be neglected. We also study the role of the defects in the metallic structures

  18. Entrapment of metal clusters in metal-organic framework channels by extended hooks anchored at open metal sites.

    Science.gov (United States)

    Zheng, Shou-Tian; Zhao, Xiang; Lau, Samuel; Fuhr, Addis; Feng, Pingyun; Bu, Xianhui

    2013-07-17

    Reported here are the new concept of utilizing open metal sites (OMSs) for architectural pore design and its practical implementation. Specifically, it is shown here that OMSs can be used to run extended hooks (isonicotinates in this work) from the framework walls to the channel centers to effect the capture of single metal ions or clusters, with the concurrent partitioning of the large channel spaces into multiple domains, alteration of the host-guest charge relationship and associated guest-exchange properties, and transfer of OMSs from the walls to the channel centers. The concept of the extended hook, demonstrated here in the multicomponent dual-metal and dual-ligand system, should be generally applicable to a range of framework types.

  19. Enzyme biosensor systems based on porous silicon photoluminescence for detection of glucose, urea and heavy metals.

    Science.gov (United States)

    Syshchyk, Olga; Skryshevsky, Valeriy A; Soldatkin, Oleksandr O; Soldatkin, Alexey P

    2015-04-15

    A phenomenon of changes in photoluminescence of porous silicon at variations in medium pH is proposed to be used as a basis for the biosensor system development. The method of conversion of a biochemical signal into an optical one is applied for direct determination of glucose and urea as well as for inhibitory analysis of heavy metal ions. Changes in the quantum yield of porous silicon photoluminescence occur at varying pH of the tested solution due to the enzyme-substrate reaction. When creating the biosensor systems, the enzymes urease and glucose oxidase (GOD) were used as a bioselective material; their optimal concentrations were experimentally determined. It was shown that the photoluminescence intensity of porous silicon increased by 1.7 times when increasing glucose concentration in the GOD-containing reaction medium from 0 to 3.0mM, and decreased by 1.45 times at the same increase in the urea concentration in the urease-containing reaction medium. The calibration curves of dependence of the biosensor system responses on the substrate concentrations are presented. It is shown that the presence of heavy metal ions (Cu(2+), Pb(2+), and Cd(2+)) in the tested solution causes an inhibition of the enzymatic reactions catalyzed by glucose oxidase and urease, which results in a restoration of the photoluminescence quantum yield of porous silicon. It is proposed to use this effect for the inhibitory analysis of heavy metal ions. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. States and properties of metallic systems at a threshold breakdown of the through holes under power laser action (part 2. Susceptibility

    Directory of Open Access Journals (Sweden)

    Kalashnikov E.

    2016-01-01

    Full Text Available Threshold breakdown of the through holes by power laser radiation of metallic foils is considered as response of metallic system to laser radiation. Binding experimentally determined response to the absolute temperature scale allows to determine the value of the imaginary part of the generalized susceptibility depending on temperature, the critical temperature of the transition “liquid metal - gas”, states of the electronic subsystems at this temperature, and the reflectance coefficient values.

  1. Removal of Chromophoric Dissolved Organic Matter and Heavy Metals in a River-Sea System: Role of Aquatic Microgel Formation

    Science.gov (United States)

    Shiu, R. F.; Lee, C. L.

    2016-12-01

    Dissolved organic carbon (DOC) polymers are complex and poorly understood mixture of organic macromolecules in environment system. Portions of these polymers spontaneously form microgels that play key roles in many biogeochemical reactions, including mediating aggregation processes, element cycling, and pollutant mobility. However, the detailed interaction of microgels-heterogeneous materials in aquatic systems is still lacking. Insight into the interaction between surrounding materials and microgels from different types of aquatic DOC polymers are extremely important, as it is crucial in determining the fate and transport of these materials. Here, we use riverine and marine DOC polymers to examine their aggregation behavior, and to evaluate the roles of microgel formation in scavenging of chromophoric dissolved organic matter (CDOM) and heavy metals in a river-sea system. Our results indicate that riverine and marine microgels did not exhibit too much difference in size ( 3-5 μm) and self-assembly curve; however, the assembly effectiveness ([microgel]/DOC) of marine samples was much higher than riverine. Instead of concentration of DOC, other factors such as types and sources of DOC polymers may control the microgel abundance in aquatic environments. After filtering water samples (microgels removed), the CDOM and selected metals (Cu, Ni, Mn) in the filtrate were quantified. CDOM and metals were concurrently removed to an extent via DOC polymer re-aggregation, which also suggested that the microgels had the sequestering capability in CDOM and metals. This finding provides an alternative route for CDOM and heavy metals removal from the water column. As such the process of re-aggregation into microgels should then be considered besides traditional phase partitioning in the assessment of the ecological risk and fate of pollutant.

  2. Nanoscale strengthening mechanisms in metallic thin film systems

    Science.gov (United States)

    Schoeppner, Rachel Lynn

    Nano-scale strengthening mechanisms for thin films were investigated for systems governed by two different strengthening techniques: nano-laminate strengthening and oxide dispersion strengthening. Films were tested under elevated temperature conditions to investigate changes in deformation mechanisms at different operating temperatures, and the structural stability. Both systems exhibit remarkable stability after annealing and thus long-term reliability. Nano-scale metallic multilayers with smaller layer thicknesses show a greater relative resistance to decreasing strength at higher temperature testing conditions than those with larger layer thicknesses. This is seen in both Cu/Ni/Nb multilayers as well as a similar tri-component bi-layer system (Cu-Ni/Nb), which removed the coherent interface from the film. Both nanoindentation and micro-pillar compression tests investigated the strain-hardening ability of these two systems to determine what role the coherent interface plays in this mechanism. Tri-layer films showed a higher strain-hardening ability as the layer thickness decreased and a higher strain-hardening exponent than the bi-layer system: verifying the presence of a coherent interface increases the strain-hardening ability of these multilayer systems. Both systems exhibited hardening of the room temperature strength after annealing, suggesting a change in microstructure has occurred, unlike that seen in other multilayer systems. Oxide dispersion strengthened Au films showed a marked increase in hardness and wear resistance with the addition of ZnO particles. The threshold for stress-induced grain-refinement as opposed to grain growth is seen at concentrations of at least 0.5 vol%. These systems exhibited stable microstructures during thermal cycling in films containing at least 1.0%ZnO. Nanoindentation experiments show the drop in hardness following annealing is almost completely attributed to the resulting grain growth. Four-point probe resistivity

  3. Determination of Systems Suitable for Study as Monotectic Binary Metallic Alloy Solidification Models

    Science.gov (United States)

    Smith, J. E., Jr.

    1983-01-01

    Succinonitrile-water and diethylene glycol-ethyl salicylate are two transparent systems which have been studied as monotectic binary metallic alloy solidification models. Being transparent, these systems allow for the direct observations of phase transformations and solidification reactions. The objective was to develop a screening technique to find systems of interest and then experimentally measure those systems. The succinonitrile-water system was used to check the procedures. To simulate the phase diagram of the system, two computer programs which determine solid-liquid and liquid-liquid equilibria were obtained. These programs use the UNIFAC method to determine activity coefficients and together with several other programs were used to predict the phase diagram. An experimental apparatus was developed and the succinonitrile-water phase diagram measured. The diagram was compared to both the simulation and literature data. Substantial differences were found in the comparisons which serve to demonstrate the need for this procedure.

  4. SYSTEMIC IMBALANCE OF ESSENTIAL METALS AND CARDIAC GENE EXPRESSION IN RATS FOLLOWING ACUTE PULMONARY ZINC EXPOSURE

    Science.gov (United States)

    We have recently demonstrated that PM containing water-soluble zinc may cause cardiac injury following pulmonary exposure. To investigate if pulmonary zinc exposure causes systemic metal imbalance and direct cardiac effects, we intratracheally (IT) instilled male Wistar Kyoto (WK...

  5. Behavior as a sentry of metal toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, B.

    1978-01-01

    Many of the toxic properties of metals are expressed as behavioral aberrations. Some of these arise from direct actions on the central nervous system. Others arise from primary events elsewhere, but still influence behavior. Toxicity may be expressed either as objectively measurable phenomena, such as ataxia, or as subjective complaints, such as depression. In neither instance is clinical medicine equipped to provide assessments of subtle, early indices of toxicity. Reviewers of visual disturbances, paresthesia, and mental retardation exemplify the potential contribution of psychology to the toxicology of metals. Behavior and nervous system functions act as sensitive mirrors of metal toxicity. Sensitivity is the prime aim in environmental health assessments. Early detection of adverse effects, before they progress to irreversibility, underlies the strategy for optimal health protection. Some of the toxic actions of metals originate in direct nervous system dysfunction. Others may reflect disturbances of systems less directly linked to behavior than the central nervous system. But behavior, because it expresses the integrated functioning of the organism, can indicate flaws in states and processes outside the nervous system.

  6. Selective extraction and recovery of rare earth metals from phosphor powders in waste fluorescent lamps using an ionic liquid system.

    Science.gov (United States)

    Yang, Fan; Kubota, Fukiko; Baba, Yuzo; Kamiya, Noriho; Goto, Masahiro

    2013-06-15

    The recycling of rare earth metals from phosphor powders in waste fluorescent lamps by solvent extraction using ionic liquids was studied. Acid leaching of rare earth metals from the waste phosphor powder was examined first. Yttrium (Y) and europium (Eu) dissolved readily in the acid solution; however, the leaching of other rare earth metals required substantial energy input. Ionization of target rare earth metals from the waste phosphor powders into the leach solution was critical for their successful recovery. As a high temperature was required for the complete leaching of all rare earth metals, ionic liquids, for which vapor pressure is negligible, were used as an alternative extracting phase to the conventional organic diluent. An extractant, N, N-dioctyldiglycol amic acid (DODGAA), which was recently developed, showed a high affinity for rare earth metal ions in liquid-liquid extraction although a conventional commercial phosphonic extractant did not. An effective recovery of the rare earth metals, Y, Eu, La and Ce, from the metal impurities, Fe, Al and Zn, was achieved from the acidic leach solution of phosphor powders using an ionic liquid containing DODGAA as novel extractant system. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Metal nanostructures for non-enzymatic glucose sensing

    International Nuclear Information System (INIS)

    Tee, Si Yin; Teng, Choon Peng; Ye, Enyi

    2017-01-01

    This review covers the recent development of metal nanostructures in electrochemical non-enzymatic glucose sensing. It highlights a variety of nanostructured materials including noble metals, other transition metals, bimetallic systems, and their hybrid with carbon-based nanomaterials. Particularly, attention is devoted to numerous approaches that have been implemented for improving the sensors performance by tailoring size, shape, composition, effective surface area, adsorption capability and electron-transfer properties. The correlation of the metal nanostructures to the glucose sensing performance is addressed with respect to the linear concentration range, sensitivity and detection limit. In overall, this review provides important clues from the recent scientific achievements of glucose sensor nanomaterials which will be essentially useful in designing better and more effective electrocatalysts for future electrochemical sensing industry. - Highlights: • Overview of recent development of metal nanostructures in electrochemical non-enzymatic glucose sensing. • Special attention is focussed on noble metals, other transition metals, bimetallic systems, and their hybrid with carbon-based nanomaterials. • Merits and limitations of various metal nanostructures in electrochemical non-enzymatic glucose sensing. • Strategies to improve the glucose sensing performance of metal nanostructures as electrocatalysts.

  8. Dynamic speciation analysis and bioavailability of metals in aquatic systems

    NARCIS (Netherlands)

    Leeuwen, van H.P.; Town, R.M.; Buffle, J.; Cleven, R.F.M.J.; Davison, W.; Puy, J.; Riemsdijk, van W.H.; Sigg, L.

    2005-01-01

    Dynamic metal speciation analysis in aquatic ecosystems is emerging as a powerful basis for development of predictions of bioavailability and reliable risk assessment strategies. A given speciation sensor is characterized by an effective time scale or kinetic window that defines the measurable metal

  9. Biosorption of heavy metals from wastewater by biosolids

    Energy Technology Data Exchange (ETDEWEB)

    Orhan, Y.; Bueyuekguengoer, H. [Ondokuz Mayis University, Engineering Faculty, Environmental Engineering Department, 55139 Samsun (Turkey); Hrenovic, J. [University of Zagreb, Faculty of Science, Department of Biology, Rooseveltov trg 6, 10000 Zagreb (Croatia)

    2006-08-15

    In a study where the removal of heavy metals from wastewater is the primary aim, the biosorption of heavy metals onto biosolids prepared as Pseudomonas aeruginosa immobilized onto granular activated carbon was investigated in batch and column systems. In the batch system, adsorption equilibriums of heavy metals were reached between 20 and 50 min, and the optimal dosage of biosolids was 0.3 g/L. The biosorption efficiencies were 84, 80, 79, 59 and 42 % for Cr(VI), Ni(II), Cu(II), Zn(II) and Cd(II) ions, respectively. The rate constants of biosorption and pore diffusion of heavy metals were 0.013-0.089 min{sup -1} and 0.026-0.690 min{sup -0.5}. In the column systems, the biosorption efficiencies for all heavy metals increased up to 81-100 %. The affinity of biosorption for various metal ions towards biosolids was decreased in the order: Cr = Ni > Cu > Zn > Cd. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  10. System and method for producing metallic iron

    Science.gov (United States)

    Englund, David J.; Schlichting, Mark; Meehan, John; Crouch, Jeremiah; Wilson, Logan

    2014-07-29

    A method of production of metallic iron nodules comprises assembling a hearth furnace having a moveable hearth comprising refractory material and having a conversion zone and a fusion zone, providing a hearth material layer comprising carbonaceous material on the refractory material, providing a layer of reducible material comprising and iron bearing material arranged in discrete portions over at least a portion of the hearth material layer, delivering oxygen gas into the hearth furnace to a ratio of at least 0.8:1 ponds of oxygen to pounds of iron in the reducible material to heat the conversion zone to a temperature sufficient to at least partially reduce the reducible material and to heat the fusion zone to a temperature sufficient to at least partially reduce the reducible material, and heating the reducible material to form one or more metallic iron nodules and slag.

  11. Metallated metal-organic frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Bury, Wojciech; Farha, Omar K.; Hupp, Joseph T.; Mondloch, Joseph E.

    2017-08-22

    Porous metal-organic frameworks (MOFs) and metallated porous MOFs are provided. Also provided are methods of metallating porous MOFs using atomic layer deposition and methods of using the metallated MOFs as catalysts and in remediation applications.

  12. THE LINK BETWEEN PLANETARY SYSTEMS, DUSTY WHITE DWARFS, AND METAL-POLLUTED WHITE DWARFS

    International Nuclear Information System (INIS)

    Debes, John H.; Walsh, Kevin J.; Stark, Christopher

    2012-01-01

    It has long been suspected that metal-polluted white dwarfs (types DAZ, DBZ, and DZ) and white dwarfs with dusty disks possess planetary systems, but a specific physical mechanism by which planetesimals are perturbed close to a white dwarf has not yet been fully posited. In this paper, we demonstrate that mass loss from a central star during post-main-sequence evolution can sweep planetesimals into interior mean motion resonances with a single giant planet. These planetesimals are slowly removed through chaotic excursions of eccentricity that in time create radial orbits capable of tidally disrupting the planetesimal. Numerical N-body simulations of the solar system show that a sufficient number of planetesimals are perturbed to explain white dwarfs with both dust and metal pollution, provided other white dwarfs have more massive relic asteroid belts. Our scenario requires only one Jupiter-sized planet and a sufficient number of asteroids near its 2:1 interior mean motion resonance. Finally, we show that once a planetesimal is perturbed into a tidal crossing orbit, it will become disrupted after the first pass of the white dwarf, where a highly eccentric stream of debris forms the main reservoir for dust-producing collisions. These simulations, in concert with observations of white dwarfs, place interesting limits on the frequency of planetary systems around main-sequence stars, the frequency of planetesimal belts, and the probability that dust may obscure future terrestrial planet finding missions.

  13. The Adsorption Langmuir Model of Transfer Metal Ti, V and Mn on System Water-Sediment in Along Side Code River, Yogyakarta

    International Nuclear Information System (INIS)

    Rini Jati Wardani; Muzakky; Agus Taftazani

    2007-01-01

    The adsorption langmuir model of transfer metal Ti, V and Mn on system water-sediment in along side Code river, Yogyakarta has been studied. For that purpose, the study is to make prediction about adsorption langmuir model of identified metal Ti, V and Mn from upstream until downstream samples water and sediment in along side Code river. The factor influenced of langmuir adsorption on transfer metal Ti, V and Mn in system water-sediment is Total Suspended Solid (TSS). The analysis showed that between TSS with metal concentration in sediment have linear correlation. The result of calculation from curve of langmuir isotherm, showed for Ti has R 2 = 0.8006 with capacities of adsorption = 0.5 mol/l and energy of adsorption = 13.286 J/mol, V has R 2 = 0.9883 with capacities of adsorption = 0.0137 mol/l and energy of adsorption = 16.64 J/mol, Mn has R 2 = 0.9624 with capacities of adsorption 0.152 mol/l and energy of adsorption = 10.51 J/mol. The conclusion from this topic about adsorption langmuir for metal Ti, V and Mn according to energy of langmuir adsorption by chemisorption process above 10 J/mo. (author)

  14. System and method for making metallic iron with reduced CO.sub.2 emissions

    Science.gov (United States)

    Kiesel, Richard F; Englund, David J; Schlichting, Mark; Meehan, John; Crouch, Jeremiah; Wilson, Logan

    2014-10-14

    A method and system for making metallic iron nodules with reduced CO.sub.2 emissions is disclosed. The method includes: assembling a linear hearth furnace having entry and exit portions, at least a conversion zone and a fusion zone, and a moving hearth adapted to move reducible iron bearing material through the furnace on contiguous hearth sections; assembling a shrouded return substantially free of air ingress extending adjacent at least the conversion and fusion zones of the furnace through which hearth sections can move from adjacent the exit portion to adjacent the entry portion of the furnace; transferring the hearth sections from the furnace to the shrouded return adjacent the exit portion; reducing reducible material in the linear hearth furnace to metallic iron nodules; and transporting gases from at least the fusion zone to the shrouded return to heat the hearth sections while in the shrouded return.

  15. Accelerating Industrial Adoption of Metal Additive Manufacturing Technology

    Science.gov (United States)

    Vartanian, Kenneth; McDonald, Tom

    2016-03-01

    While metal additive manufacturing (AM) technology has clear benefits, there are still factors preventing its adoption by industry. These factors include the high cost of metal AM systems, the difficulty for machinists to learn and operate metal AM machines, the long approval process for part qualification/certification, and the need for better process controls; however, the high AM system cost is the main barrier deterring adoption. In this paper, we will discuss an America Makes-funded program to reduce AM system cost by combining metal AM technology with conventional computerized numerical controlled (CNC) machine tools. Information will be provided on how an Optomec-led team retrofitted a legacy CNC vertical mill with laser engineered net shaping (LENS®—LENS is a registered trademark of Sandia National Labs) AM technology, dramatically lowering deployment cost. The upgraded system, dubbed LENS Hybrid Vertical Mill, enables metal additive and subtractive operations to be performed on the same machine tool and even on the same part. Information on the LENS Hybrid system architecture, learnings from initial system deployment and continuing development work will also be provided to help guide further development activities within the materials community.

  16. A System of Test Methods for Sheet Metal Forming Tribology

    DEFF Research Database (Denmark)

    Bay, Niels; Olsson, David Dam; Andreasen, Jan Lasson

    2007-01-01

    Sheet metal forming of tribologically difficult materials such as stainless steel, Al-alloys and Ti-alloys or forming in tribologically difficult operations like ironing, punching or deep drawing of thick plate requires often use of environmentally hazardous lubricants such as chlorinated paraffin...... oils in order to avoid galling. The present paper describes a systematic research in the development of new, environmentally harmless lubricants focusing on the lubricant testing aspects. A system of laboratory tests has been developed to study the lubricant performance under the very varied conditions...... appearing in different sheet forming operations such as stamping, deep drawing, ironing and punching. The laboratory tests have been especially designed to model the conditions in industrial production....

  17. A survey of monitoring and assay systems for release of metals from radiation controlled areas at LANL.

    Energy Technology Data Exchange (ETDEWEB)

    Gruetzmacher, K. M. (Kathleen M.); MacArthur, D. W. (Duncan W.)

    2002-01-01

    At Los Alamos National Laboratory (LANL), a recent effort in waste minimization has focused on scrap metal from radiological controlled areas (RCAs). In particular, scrap metal from RCAs needs to be dispositioned in a reasonable and cost effective manner. Recycling of DOE scrap metals from RCAs is currently under a self-imposed moratorium. Since recycling is not available and reuse is difficult, often metal waste from RCAs, which could otherwise be recycled, is disposed of as low-level waste. Estimates at LANL put the cost of low-level waste disposal at $550 to $4000 per cubic meter, depending on the type of waste and the disposal site. If the waste is mixed, the cost for treatment and disposal can be as high as $50,000 per cubic meter. Disposal of scrap metal as low-level waste uses up valuable space in the low-level waste disposal areas and requires transportation to the disposal site under Department of Transportation (DOT) regulations for low-level waste. In contrast, disposal as non-radioactive waste costs as little as $2 per cubic meter. While recycling is unavailable, disposing of the metal at an industrial waste site could be the best solution for this waste stream. A Green Is Clean (GIC) type verification program needs to be in place to provide the greatest assurance that the waste does not contain DOE added radioactivity. This paper is a review of available and emerging radiation monitoring and assay systems that could be used for scrap metal as part of the LANL GIC program.

  18. Experimental Liquidus Studies of the Pb-Cu-Si-O System in Equilibrium with Metallic Pb-Cu Alloys

    Science.gov (United States)

    Shevchenko, M.; Nicol, S.; Hayes, P. C.; Jak, E.

    2018-03-01

    Phase equilibria of the Pb-Cu-Si-O system have been investigated in the temperature range from 1073 K to 1673 K (800 °C to 1400 °C) for oxide liquid (slag) in equilibrium with solid Cu metal and/or liquid Pb-Cu alloy, and solid oxide phases: (a) quartz or tridymite (SiO2) and (b) cuprite (Cu2O). High-temperature equilibration on silica or copper substrates was performed, followed by quenching, and direct measurement of Pb, Cu, and Si concentrations in the liquid and solid phases using the electron probe X-ray microanalysis has been employed to accurately characterize the system in equilibrium with Cu or Pb-Cu metal. All results are projected onto the PbO-"CuO0.5"-SiO2 plane for presentation purposes. The present study is the first-ever systematic investigation of this system to describe the slag liquidus temperatures in the silica and cuprite primary phase fields.

  19. Electronic transport properties of carbon nanotube metal-semiconductor-metal

    Directory of Open Access Journals (Sweden)

    F Khoeini

    2008-07-01

    Full Text Available  In this work, we study electronic transport properties of a quasi-one dimensional pure semi-conducting Zigzag Carbon Nanotube (CNT attached to semi-infinite clean metallic Zigzag CNT leads, taking into account the influence of topological defect in junctions. This structure may behave like a field effect transistor. The calculations are based on the tight-binding model and Green’s function method, in which the local density of states(LDOS in the metallic section to semi-conducting section, and muli-channel conductance of the system are calculated in the coherent and linear response regime, numerically. Also we have introduced a circuit model for the system and investigated its current. The theoretical results obtained, can be a base, for developments in designing nano-electronic devices.

  20. Emissions from a Diesel Engine using Fe-based Fuel Additives and a Sintered Metal Filtration System.

    Science.gov (United States)

    Bugarski, Aleksandar D; Hummer, Jon A; Stachulak, Jozef S; Miller, Arthur; Patts, Larry D; Cauda, Emanuele G

    2016-03-01

    A series of laboratory tests were conducted to assess the effects of Fe-containing fuel additives on aerosols emitted by a diesel engine retrofitted with a sintered metal filter (SMF) system. Emission measurements performed upstream and downstream of the SMF system were compared, for cases when the engine was fueled with neat ultralow sulfur diesel (ULSD) and with ULSD treated with two formulations of additives containing Fe-based catalysts. The effects were assessed for four steady-state engine operating conditions and one transient cycle. The results showed that the SMF system reduced the average total number and surface area concentrations of aerosols by more than 100-fold. The total mass and elemental carbon results confirmed that the SMF system was indeed very effective in the removal of diesel aerosols. When added at the recommended concentrations (30 p.p.m. of iron), the tested additives had minor adverse impacts on the number, surface area, and mass concentrations of filter-out (FOut) aerosols. For one of the test cases, the additives may have contributed to measurable concentrations of engine-out (EOut) nucleation mode aerosols. The additives had only a minor impact on the concentration and size distribution of volatile and semi-volatile FOut aerosols. Metal analysis showed that the introduction of Fe with the additives substantially increased Fe concentration in the EOut, but the SMF system was effective in removal of Fe-containing aerosols. The FOut Fe concentrations for all three tested fuels were found to be much lower than the corresponding EOut Fe concentrations for the case of untreated ULSD fuel. The results support recommendations that these additives should not be used in diesel engines unless they are equipped with exhaust filtration systems. Since the tested SMF system was found to be very efficient in removing Fe introduced by the additives, the use of these additives should not result in a measurable increase in emissions of de novo generated

  1. THE METALLICITY BIMODALITY OF GLOBULAR CLUSTER SYSTEMS: A TEST OF GALAXY ASSEMBLY AND OF THE EVOLUTION OF THE GALAXY MASS-METALLICITY RELATION

    International Nuclear Information System (INIS)

    Tonini, Chiara

    2013-01-01

    We build a theoretical model to study the origin of the globular cluster metallicity bimodality in the hierarchical galaxy assembly scenario. The model is based on empirical relations such as the galaxy mass-metallicity relation [O/H]-M star as a function of redshift, and on the observed galaxy stellar mass function up to redshift z ∼ 4. We make use of the theoretical merger rates as a function of mass and redshift from the Millennium simulation to build galaxy merger trees. We derive a new galaxy [Fe/H]-M star relation as a function of redshift, and by assuming that globular clusters share the metallicity of their original parent galaxy at the time of their formation, we populate the merger tree with globular clusters. We perform a series of Monte Carlo simulations of the galaxy hierarchical assembly, and study the properties of the final globular cluster population as a function of galaxy mass, assembly and star formation history, and under different assumptions for the evolution of the galaxy mass-metallicity relation. The main results and predictions of the model are the following. (1) The hierarchical clustering scenario naturally predicts a metallicity bimodality in the galaxy globular cluster population, where the metal-rich subpopulation is composed of globular clusters formed in the galaxy main progenitor around redshift z ∼ 2, and the metal-poor subpopulation is composed of clusters accreted from satellites, and formed at redshifts z ∼ 3-4. (2) The model reproduces the observed relations by Peng et al. for the metallicities of the metal-rich and metal-poor globular cluster subpopulations as a function of galaxy mass; the positions of the metal-poor and metal-rich peaks depend exclusively on the evolution of the galaxy mass-metallicity relation and the [O/Fe], both of which can be constrained by this method. In particular, we find that the galaxy [O/Fe] evolves linearly with redshift from a value of ∼0.5 at redshift z ∼ 4 to a value of ∼0.1 at

  2. Development of a Hemispherical Metal Diaphragm for Single-Cycle Liquid-Metal Positive Expulsion Systems

    National Research Council Canada - National Science Library

    Gorland, Sol

    1965-01-01

    This report presents experimental results pertaining to the design and development of a metallic expulsion diaphragm for single-cycle positive expulsion of high-temperature liquid in an agravity condition...

  3. Noble Metal/Ceramic Composites in Flame Processes

    DEFF Research Database (Denmark)

    Schultz, Heiko; Madler, Lutz; Strobel, Reto

    conditions influence the resulting noble metal particles size in those systems [1]. For every specific application the particle size and the metal/metal oxide interaction affect the performance of these nano-composite materials [2]. Recently, aerosol processes have been successfully used to produce platinum...

  4. Treatment of transverse patellar fractures: a comparison between metallic and non-metallic implants.

    Science.gov (United States)

    Heusinkveld, Maarten H G; den Hamer, Anniek; Traa, Willeke A; Oomen, Pim J A; Maffulli, Nicola

    2013-01-01

    Several methods of transverse patellar fixation have been described. This study compares the clinical outcome and the occurrence of complications of various fixation methods. The databases PubMed, Web of Science, Science Direct, Google Scholar and Google were searched. A direct comparison between fixation techniques using mixed or non-metallic implants and metallic K-wire and tension band fixation shows no significant difference in clinical outcome between both groups. Additionally, studies reporting novel operation techniques show good clinical results. Studies describing the treatment of patients using non-metallic or mixed implants are fewer compared with those using metallic fixation. A large variety of clinical scoring systems were used for assessing the results of treatment, which makes direct comparison difficult. More data of fracture treatment using non-metallic or mixed implants is needed to achieve a more balanced comparison.

  5. Impacts of metal and metal oxide nanoparticles on marine organisms

    International Nuclear Information System (INIS)

    Baker, Tony J.; Tyler, Charles R.; Galloway, Tamara S.

    2014-01-01

    Increasing use of metal and metal oxide nanoparticles [Me(O)NPs] in products means many will inevitably find their way into marine systems. Their likely fate here is sedimentation following hetero-aggregation with natural organic matter and/or free anions, putting benthic, sediment-dwelling and filter feeding organisms most at risk. In marine systems, Me(O)NPs can absorb to micro-organisms with potential for trophic transfer following consumption. Filter feeders, especially bivalves, accumulate Me(O)NPs through trapping them in mucus prior to ingestion. Benthic in-fauna may directly ingest sedimented Me(O)NPs. In fish, uptake is principally via the gut following drinking, whilst Me(O)NPs caught in gill mucus may affect respiratory processes and ion transport. Currently, environmentally-realistic Me(O)NP concentrations are unlikely to cause significant adverse acute health problems, however sub-lethal effects e.g. oxidative stresses have been noted in many organisms, often deriving from dissolution of Ag, Cu or Zn ions, and this could result in chronic health impacts. -- Highlights: • Nanoparticle (NP) use increasing, and NPs ultimately discharged to marine systems. • Metal ion dissolution from NPs causes oxidative stress at relevant concentrations. • Bioaccumulation and trophic transfer of NPs likely at all levels of marine food webs. • Biofilms and filter feeders are major NP accumulators, but many Classes lack study. • Current release levels unlikely to cause chronic damage, but may be a future issue. -- Exposure to metal (oxide) nanoparticles causes sub-lethal effects in marine organisms, the extent of which is related principally to the organisms' feeding regime, habitat and lifestyle

  6. A framework for ecological risk assessment of metal mixtures in aquatic systems.

    Science.gov (United States)

    Nys, Charlotte; Van Regenmortel, Tina; Janssen, Colin R; Oorts, Koen; Smolders, Erik; De Schamphelaere, Karel A C

    2018-03-01

    Although metal mixture toxicity has been studied relatively intensely, there is no general consensus yet on how to incorporate metal mixture toxicity into aquatic risk assessment. We combined existing data on chronic metal mixture toxicity at the species level with species sensitivity distribution (SSD)-based in silico metal mixture risk predictions at the community level for mixtures of Ni, Zn, Cu, Cd, and Pb, to develop a tiered risk assessment scheme for metal mixtures in freshwater. Generally, independent action (IA) predicts chronic metal mixture toxicity at the species level most accurately, whereas concentration addition (CA) is the most conservative model. Mixture effects are noninteractive in 69% (IA) and 44% (CA) and antagonistic in 15% (IA) and 51% (CA) of the experiments, whereas synergisms are only observed in 15% (IA) and 5% (CA) of the experiments. At low effect sizes (∼ 10% mixture effect), CA overestimates metal mixture toxicity at the species level by 1.2-fold (i.e., the mixture interaction factor [MIF]; median). Species, metal presence, or number of metals does not significantly affect the MIF. To predict metal mixture risk at the community level, bioavailability-normalization procedures were combined with CA or IA using SSD techniques in 4 different methods, which were compared using environmental monitoring data of a European river basin (the Dommel, The Netherlands). We found that the simplest method, in which CA is directly applied to the SSD (CA SSD ), is also the most conservative method. The CA SSD has median margins of safety (MoS) of 1.1 and 1.2 respectively for binary mixtures compared with the theoretically more consistent methods of applying CA or IA to the dose-response curve of each species individually prior to estimating the fraction of affected species (CA DRC or IA DRC ). The MoS increases linearly with an increasing number of metals, up to 1.4 and 1.7 for quinary mixtures (median) compared with CA DRC and IA DRC

  7. PLUTONIUM METALLIC FUELS FOR FAST REACTORS

    Energy Technology Data Exchange (ETDEWEB)

    STAN, MARIUS [Los Alamos National Laboratory; HECKER, SIEGFRIED S. [Los Alamos National Laboratory

    2007-02-07

    Early interest in metallic plutonium fuels for fast reactors led to much research on plutonium alloy systems including binary solid solutions with the addition of aluminum, gallium, or zirconium and low-melting eutectic alloys with iron and nickel or cobalt. There was also interest in ternaries of these elements with plutonium and cerium. The solid solution and eutectic alloys have most unusual properties, including negative thermal expansion in some solid-solution alloys and the highest viscosity known for liquid metals in the Pu-Fe system. Although metallic fuels have many potential advantages over ceramic fuels, the early attempts were unsuccessful because these fuels suffered from high swelling rates during burn up and high smearing densities. The liquid metal fuels experienced excessive corrosion. Subsequent work on higher-melting U-PuZr metallic fuels was much more promising. In light of the recent rebirth of interest in fast reactors, we review some of the key properties of the early fuels and discuss the challenges presented by the ternary alloys.

  8. RAPID COMMUNICATION: Magnetic resonance imaging inside metallic vessels

    Science.gov (United States)

    Han, Hui; Balcom, Bruce J.

    2010-10-01

    We introduce magnetic resonance imaging (MRI) measurements inside metallic vessels. Until now, MRI has been unusable inside metallic vessels because of eddy currents in the walls. We have solved the problem and generated high quality images by employing a magnetic field gradient monitoring method. The ability to image within metal enclosures and structures means many new samples and systems are now amenable to MRI. Most importantly this study will form the basis of new MRI-compatible metallic pressure vessels, which will permit MRI of macroscopic systems at high pressure.

  9. Coherently-enabled environmental control of optics and energy transfer pathways of hybrid quantum dot-metallic nanoparticle systems.

    Science.gov (United States)

    Hatef, Ali; Sadeghi, Seyed M; Fortin-Deschênes, Simon; Boulais, Etienne; Meunier, Michel

    2013-03-11

    It is well-known that optical properties of semiconductor quantum dots can be controlled using optical cavities or near fields of localized surface plasmon resonances (LSPRs) of metallic nanoparticles. In this paper we study the optics, energy transfer pathways, and exciton states of quantum dots when they are influenced by the near fields associated with plasmonic meta-resonances. Such resonances are formed via coherent coupling of excitons and LSPRs when the quantum dots are close to metallic nanorods and driven by a laser beam. Our results suggest an unprecedented sensitivity to the refractive index of the environment, causing significant spectral changes in the Förster resonance energy transfer from the quantum dots to the nanorods and in exciton transition energies. We demonstrate that when a quantum dot-metallic nanorod system is close to its plasmonic meta-resonance, we can adjust the refractive index to: (i) control the frequency range where the energy transfer from the quantum dot to the metallic nanorod is inhibited, (ii) manipulate the exciton transition energy shift of the quantum dot, and (iii) disengage the quantum dot from the metallic nanoparticle and laser field. Our results show that near meta-resonances the spectral forms of energy transfer and exciton energy shifts are strongly correlated to each other.

  10. Polymer-supported metals and metal oxide nanoparticles: synthesis, characterization, and applications

    International Nuclear Information System (INIS)

    Sarkar, Sudipta; Guibal, E.; Quignard, F.; SenGupta, A. K.

    2012-01-01

    Metal and metal oxide nanoparticles exhibit unique properties in regard to sorption behaviors, magnetic activity, chemical reduction, ligand sequestration among others. To this end, attempts are being continuously made to take advantage of them in multitude of applications including separation, catalysis, environmental remediation, sensing, biomedical applications and others. However, metal and metal oxide nanoparticles lack chemical stability and mechanical strength. They exhibit extremely high pressure drop or head loss in fixed-bed column operation and are not suitable for any flow-through systems. Also, nanoparticles tend to aggregate; this phenomenon reduces their high surface area to volume ratio and subsequently reduces effectiveness. By appropriately dispersing metal and metal oxide nanoparticles into synthetic and naturally occurring polymers, many of the shortcomings can be overcome without compromising the parent properties of the nanoparticles. Furthermore, the appropriate choice of the polymer host with specific functional groups may even lead to the enhancement of the properties of nanoparticles. The synthesis of hybrid materials involves two broad pathways: dispersing the nanoparticles (i) within pre-formed or commercially available polymers; and (ii) during the polymerization process. This review presents a broad coverage of nanoparticles and polymeric/biopolymeric host materials and the resulting properties of the hybrid composites. In addition, the review discusses the role of the Donnan membrane effect exerted by the host functionalized polymer in harnessing the desirable properties of metal and metal oxide nanoparticles for intended applications.

  11. Carbon Formation and Metal Dusting in Hot-Gas Cleanup Systems of Coal Gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Tortorelli, Peter F.; Judkins, Roddie R.; DeVan, Jackson H.; Wright, Ian G.

    1995-12-31

    There are several possible materials/systems degradation modes that result from gasification environments with appreciable carbon activities. These processes, which are not necessarily mutually exclusive, include carbon deposition, carburization, metal dusting, and CO disintegration of refractories. Carbon formation on solid surfaces occurs by deposition from gases in which the carbon activity (a sub C) exceeds unity. The presence of a carbon layer CO can directly affect gasifier performance by restricting gas flow, particularly in the hot gas filter, creating debris (that may be deposited elsewhere in the system or that may cause erosive damage of downstream components), and/or changing the catalytic activity of surfaces.

  12. Metal-insulator transition in disordered systems from the one-body density matrix

    DEFF Research Database (Denmark)

    Olsen, Thomas; Resta, Raffaele; Souza, Ivo

    2017-01-01

    The insulating state of matter can be probed by means of a ground state geometrical marker, which is closely related to the modern theory of polarization (based on a Berry phase). In the present work we show that this marker can be applied to determine the metal-insulator transition in disordered...... the one-body density matrix. The approach has a general ab initio formulation and could in principle be applied to realistic disordered materials by standard electronic structure methods....... systems. In particular, for noninteracting systems the geometrical marker can be obtained from the configurational average of the norm-squared one-body density matrix, which can be calculated within open as well as periodic boundary conditions. This is in sharp contrast to a classification based...

  13. Electronic structure, bonding and chemisorption in metallic hydrides

    International Nuclear Information System (INIS)

    Ward, J.W.

    1980-01-01

    Problems that can arise during the cycling steps for a hydride storage system usually involve events at surfaces. Chemisorption and reaction processes can be affected by small amounts of contaminants that may act as catalytic poisons. The nature of the poisoning process can vary greatly for the different metals and alloys that form hydrides. A unifying concept is offered, which satisfactorily correlates many of the properties of transition-metal, rare-earth and actinide hydrides. The metallic hydrides can be differentiated on the basis of electronegativity, metallic radius (valence) and electronic structure. For those systems where there are d (transition metals) or f (early actinides) electrons near the Fermi level a broad range of chemical and catalytic behaviors are found, depending on bandwidth and energy. The more electropositive metals (rare-earths, actinides, transition metals with d > 5) dissolve hydrogen and form hydrides by an electronically somewhat different process, and as a class tend to adsorb electrophobic molecules. The net charge-transfer in either situation is subtle; however, the small differences are responsible for many of the observed structural, chemical, and catalytic properties in these hydride systems

  14. Effect of metal doping on structural characteristics of amorphous carbon system: A first-principles study

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaowei; Zhang, Dong [Key Laboratory of Marine Materials and Related Technologies, Key Laboratory of Marine Materials and Protective Technologies of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Lee, Kwang-Ryeol, E-mail: krlee@kist.re.kr [Computational Science Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Wang, Aiying, E-mail: aywang@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Key Laboratory of Marine Materials and Protective Technologies of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2016-05-31

    First-principles calculation was performed to investigate the effect of metal doping on the structural characteristics of amorphous carbon system, and the 3d transition metals (TM) were particularly selected as representative case. Results showed that the total energy in TM–C systems caused by distorting the bond angles was reduced distinctly for comparison with that in C–C system. Further electronic structure revealed that as the 3d electrons of doped TM increased, the bond characteristic of highest occupied molecular orbital changed from bonding (Sc, Ti) to nonbonding (V, Cr, Mn, Fe) and finally to antibonding (Co, Ni, Cu) between the TM and C atoms. Meanwhile, the TM–C bond presented a mixture of the covalent and ionic characters. The decrease of strength and directionality of TM–C bonds resulted in the total energy change upon bond angle distortion, which demonstrated that the bond characteristics played an important role in reducing residual stress of TM-doped amorphous carbon systems. - Highlights: • The bond characteristics as 3d electrons changed from bonding, nonbonding to antibonding. • The TM–C bond was a mixture of covalent and ionic characters. • Reduced strength and directionality of TM–C bond led to small distortion energy change. • The weak TM–C bond accounted for the reduced compressive stress caused by TM.

  15. Microbial Remediation of Metals in Soils

    Science.gov (United States)

    Hietala, K. A.; Roane, T. M.

    Of metal-contaminated systems, metal-contaminated soils present the greatest challenge to remediation efforts because of the structural, physical, chemical, and biological heterogeneities encountered in soils. One of the confounding issues surrounding metal remediation is that metals can be readily re-mobilized, requiring constant monitoring of metal toxicity in sites where metals are not removed. Excessive metal content in soils can impact air, surface water, and groundwater quality. However, our understanding of how metals affect organisms, from bacteria to plants and animals, and our ability to negate the toxicity of metals are in their infancies. The ubiquity of metal contamination in developing and industrialized areas of the world make remediation of soils via removal, containment, and/or detoxification of metals a primary concern. Recent examples of the health and environmental consequences of metal contamination include arsenic in drinking water (Wang and Wai 2004), mercury levels in fish (Jewett and Duffy 2007), and metal uptake by agricultural crops (Howe et al. 2005). The goal of this chapter is to summarize the traditional approaches and recent developments using microorganisms and microbial products to address metal toxicity and remediation.

  16. ABOUT THE WAYS OF THE SYSTEM ANALYSIS OF METAL MOVEMENT IN GATING SYSTEMS BASED ON THE NUMERICAL SOLUTIONS OF NAVIER-STOKES EQUATIONS

    Directory of Open Access Journals (Sweden)

    S. G. Lizouzov

    2014-01-01

    Full Text Available Numerical modeling of distribution of the fields of speeds projections on axes X, Y, Z in gating system with the casting “Case of conical pair” for various temporal values is carried out. Numerical criteria for assessment of metal movement through the feeders having various spatial location relative to the gating system are offered. Dynamics of change of the offered criteria on the basis of integral average value of the speed component on axes X, Y, Z in the gating systems at the outlet from feeder is calculated.

  17. Sheet-bulk metal forming – forming of functional components from sheet metals

    Directory of Open Access Journals (Sweden)

    Merklein Marion

    2015-01-01

    Full Text Available The paper gives an overview on the application of sheet-bulk metal forming operations in both scientific and industrial environment. Beginning with the need for an innovative forming technology, the definition of this new process class is introduced. The rising challenges of the application of bulk metal forming operations on sheet metals are presented and the demand on a holistic investigation of this topic is motivated. With the help of examples from established production processes, the latest state of technology and the lack on fundamental knowledge is shown. Furthermore, perspectives regarding new research topics within sheet-bulk metal forming are presented. These focus on processing strategies to improve the quality of functional components by the application of process-adapted semi-finished products as well as the local adaption of the tribological system.

  18. Inhalation hazards from machining beryllium metal

    International Nuclear Information System (INIS)

    Hoover, M.D.; Finch, G.L.; Mewhinney, J.A.; Eidson, A.F.

    1987-01-01

    Beryllium metal has special nuclear and structural properties that make it useful for applications in fission and fusion reactor designs. Unfortunately, concerns for its toxicity have made designers wary of using beryllium metal. The work being reported here was undertaken to characterize the aerosols produced by two very common operations performed during preparation or modification of components for use in reactor systems: sawing and milling of beryllium metal. The study also covered beryllium metal alloys to allow comparison. Information from this study is to enable better assessments of the risk of using beryllium metal in reactor designs

  19. DOE mixed waste metals partition in a rotary kiln wet off-gas system

    International Nuclear Information System (INIS)

    Burns, D.B.; Looper, M.G.

    1994-01-01

    In 1996, the Savannah River Site plans to begin operation of the Consolidated Incineration Facility (CIF) to treat solid and liquid RCRA hazardous and mixed wastes. Test burns were conducted using surrogate CIF wastes spiked with hazardous metals and organics. The partition of metals between the kiln bottom ash, scrubber blowdown solution, and stack gas was measured as a function of kiln temperature, waste chloride content, and waste form (liquid or solid). Three waste simulants were used in these tests, a high and low chloride solid waste mix (paper, plastic, latex, PVC), and a liquid waste mix (benzene and chlorobenzene). An aqueous solution containing: antimony, arsenic, barium, cadmium, chromium, lead, mercury, nickel, silver, and thallium was added to the waste to determine metals fate under various combustion conditions. Test results were used to divide the metals into three general groups, volatile, semi-volatile, and nonvolatile metals. Mercury was the only volatile metal. No mercury remained in the kiln bottom ash under any incineration condition. Lead, cadmium, thallium, and silver exhibited semi-volatile behavior. The partition between the kiln ash, blowdown, and stack gas depended on incineration conditions. Chromium, nickel, barium, antimony, and arsenic exhibited nonvolatile behavior, with greater than 90 wt % of the metal remaining in the kiln bottom ash. Incineration temperature had a significant effect on the partition of volatile and semi-volatile metals, and no effect on nonvolatile metal partition. As incineration temperatures were increased, the fraction of metal leaving the kiln increased. Three metals, lead, cadmium, and mercury showed a relationship between chloride concentration in the waste and metals partition. Increasing the concentration of chlorides in the waste or burning liquid waste versus solid waste resulted in a larger fraction of metal exiting the kiln

  20. Supporting the national energy needs for the early 21st century with the advanced liquid metal reactor system (ALMRS)

    International Nuclear Information System (INIS)

    Hutchins, B.A.; Quinn, J.E.; Thompson, M.L.

    1991-01-01

    This paper presents a cost effective approach to providing a major contribution to the electricity needs of the United States in the early 21st century through an integrated Advanced Liquid Metal Reactor System (ALMRS). This system has several synergistic components which are under development by the United States Department of Energy (DOE): the modular, passively safe ALMR reactor design; metal fuel recycle (aka IFR); and the processing of LWR spent fuel to use as startup fuel for the ALMR. Each of these components contributes to an overall system behavior that will be able to provide an important portion of the United States' electrical energy needs beginning about the year 2010, while at the same time translating some fuel wastes of the LWR spent fuel to an asset. This paper describes each of these components and their synergism. Economic projections and busbar costs for this system are also presented

  1. Selective extraction and recovery of rare earth metals from phosphor powders in waste fluorescent lamps using an ionic liquid system

    International Nuclear Information System (INIS)

    Yang, Fan; Kubota, Fukiko; Baba, Yuzo; Kamiya, Noriho; Goto, Masahiro

    2013-01-01

    Highlights: • Recycling of rare earth metals from fluorescent lamps was conducted by ionic liquid-mediated extraction. • Acid leaching from a waste phosphor powder was carried out using sulfuric and nitric acids. • An ionic liquid was used as extracting solvent for the rare earth metals. • Selective extraction of rare earth metals from leach solutions was attained. •The extracting ionic liquid phase was recyclable in the recovery process. -- Abstract: The recycling of rare earth metals from phosphor powders in waste fluorescent lamps by solvent extraction using ionic liquids was studied. Acid leaching of rare earth metals from the waste phosphor powder was examined first. Yttrium (Y) and europium (Eu) dissolved readily in the acid solution; however, the leaching of other rare earth metals required substantial energy input. Ionization of target rare earth metals from the waste phosphor powders into the leach solution was critical for their successful recovery. As a high temperature was required for the complete leaching of all rare earth metals, ionic liquids, for which vapor pressure is negligible, were used as an alternative extracting phase to the conventional organic diluent. An extractant, N, N-dioctyldiglycol amic acid (DODGAA), which was recently developed, showed a high affinity for rare earth metal ions in liquid–liquid extraction although a conventional commercial phosphonic extractant did not. An effective recovery of the rare earth metals, Y, Eu, La and Ce, from the metal impurities, Fe, Al and Zn, was achieved from the acidic leach solution of phosphor powders using an ionic liquid containing DODGAA as novel extractant system

  2. Selective extraction and recovery of rare earth metals from phosphor powders in waste fluorescent lamps using an ionic liquid system

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Fan; Kubota, Fukiko; Baba, Yuzo [Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Kamiya, Noriho [Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Center for Future Chemistry, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Goto, Masahiro, E-mail: m-goto@mail.cstm.kyushu-u.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Center for Future Chemistry, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan)

    2013-06-15

    Highlights: • Recycling of rare earth metals from fluorescent lamps was conducted by ionic liquid-mediated extraction. • Acid leaching from a waste phosphor powder was carried out using sulfuric and nitric acids. • An ionic liquid was used as extracting solvent for the rare earth metals. • Selective extraction of rare earth metals from leach solutions was attained. •The extracting ionic liquid phase was recyclable in the recovery process. -- Abstract: The recycling of rare earth metals from phosphor powders in waste fluorescent lamps by solvent extraction using ionic liquids was studied. Acid leaching of rare earth metals from the waste phosphor powder was examined first. Yttrium (Y) and europium (Eu) dissolved readily in the acid solution; however, the leaching of other rare earth metals required substantial energy input. Ionization of target rare earth metals from the waste phosphor powders into the leach solution was critical for their successful recovery. As a high temperature was required for the complete leaching of all rare earth metals, ionic liquids, for which vapor pressure is negligible, were used as an alternative extracting phase to the conventional organic diluent. An extractant, N, N-dioctyldiglycol amic acid (DODGAA), which was recently developed, showed a high affinity for rare earth metal ions in liquid–liquid extraction although a conventional commercial phosphonic extractant did not. An effective recovery of the rare earth metals, Y, Eu, La and Ce, from the metal impurities, Fe, Al and Zn, was achieved from the acidic leach solution of phosphor powders using an ionic liquid containing DODGAA as novel extractant system.

  3. Rapid hydrogen charging on metal hydride negative electrode of Fuel Cell/Battery (FCB) systems

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Bokkyu; Lee, Sunmook; Kawai, Hiroyuki; Fushimi, Chihiro; Tsutsumi, Atsushi [Collaborative Research Center for Energy Engineering, Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan)

    2009-02-15

    The characteristics of rapid gaseous H{sub 2} charging/electrochemical discharging of the metal hydride negative electrode were investigated for the application in Fuel Cell/Battery (FCB) systems. They were evaluated with the H{sub 2} gas absorption, followed by the subsequent electrochemical discharging in the electrolyte solution (6M KOH). Then, the cyclability of charge-discharge was also examined. It was observed that more than 70% of the theoretical capacity was charged within 10 min with 0.3 MPa and 0.5 MPa of the initial H{sub 2} pressures. The electrochemical discharge curve showed that more than 86% of the absorbed H{sub 2} was discharged. Furthermore, the cycled charge-discharge process indicated that the H{sub 2} gas charge and electrochemical discharge process is an effective way to rapidly charge and activate the metal hydride without degeneration. (author)

  4. Liquid metal cooling of synchrotron optics

    International Nuclear Information System (INIS)

    Smither, R.K.

    1993-01-01

    The installation of insertion devices at existing synchrotron facilities around the world has stimulated the development of new ways to cool the optical elements in the associated x-ray beamlines. Argonne has been a leader in the development of liquid metal cooling for high heat load x-ray optics for the next generation of synchrotron facilities. The high thermal conductivity, high volume specific heat, low kinematic viscosity, and large working temperature range make liquid metals a very efficient heat transfer fluid. A wide range of liquid metals were considered in the initial phase of this work. The most promising liquid metal cooling fluid identified to date is liquid gallium, which appears to have all the desired properties and the fewest number of undesired features of the liquid metals examined. Besides the special features of liquid metals that make them good heat transfer fluids, the very low vapor pressure over a large working temperature range make liquid gallium an ideal cooling fluid for use in a high vacuum environment. A leak of the liquid gallium into the high vacuum and even into very high vacuum areas will not result in any detectable vapor pressure and may even improve the vacuum environment as the liquid gallium combines with any water vapor or oxygen present in the system. The practical use of a liquid metal for cooling silicon crystals and other high heat load applications depends on having a convenient and efficient delivery system. The requirements for a typical cooling system for a silicon crystal used in a monochromator are pumping speeds of 2 to 5 gpm (120 cc per sec to 600 cc per sec) at pressures up to 100 psi. No liquid metal pump with these capabilities was available commercially when this project was started, so it was necessary to develop a suitable pump in house

  5. Metal-Containing Molecules Beyond the Solar System: a Laboratory and Radio Astronomical Perspective

    Science.gov (United States)

    Ziurys, L. M.

    2010-06-01

    Although the history of interstellar molecules began around 1970, with the millimeter-wave detection of CO in the Orion Nebula, metal-containing species have been somewhat elusive for astronomical searches. Only in the past two decades have metal-bearing molecules been identified in space, starting with metal halides (NaCl, KCl, AlCl, and AlF), and then metal cyanide and isocyanide species (MgNC, MgCN, NaCN, and AlNC). Moreover, the metal-containing molecules seemed to be present in a single astronomical object: the envelope of a dying, carbon-rich star, IRC+10216. However, with improvements both in laboratory spectroscopy and telescope sensitivity, it is becoming clear that the relevance of metal-containing species in astrophysics is increasing. Metal oxide and hydroxide species, such as AlO and AlOH, have recently been identified in interstellar space. Metal-containing molecules are now being found in other astronomical sources, such as the oxygen-rich shell surrounding VY Canis Majoris, a supergiant star. These new astronomical discoveries will be presented, as well as the laboratory measurements that made them possible. New directions in rotational spectroscopy of metal-bearing molecules will also be discussed.

  6. Process Parameter Optimization of Extrusion-Based 3D Metal Printing Utilizing PW-LDPE-SA Binder System.

    Science.gov (United States)

    Ren, Luquan; Zhou, Xueli; Song, Zhengyi; Zhao, Che; Liu, Qingping; Xue, Jingze; Li, Xiujuan

    2017-03-16

    Recently, with a broadening range of available materials and alteration of feeding processes, several extrusion-based 3D printing processes for metal materials have been developed. An emerging process is applicable for the fabrication of metal parts into electronics and composites. In this paper, some critical parameters of extrusion-based 3D printing processes were optimized by a series of experiments with a melting extrusion printer. The raw materials were copper powder and a thermoplastic organic binder system and the system included paraffin wax, low density polyethylene, and stearic acid (PW-LDPE-SA). The homogeneity and rheological behaviour of the raw materials, the strength of the green samples, and the hardness of the sintered samples were investigated. Moreover, the printing and sintering parameters were optimized with an orthogonal design method. The influence factors in regard to the ultimate tensile strength of the green samples can be described as follows: infill degree > raster angle > layer thickness. As for the sintering process, the major factor on hardness is sintering temperature, followed by holding time and heating rate. The highest hardness of the sintered samples was very close to the average hardness of commercially pure copper material. Generally, the extrusion-based printing process for producing metal materials is a promising strategy because it has some advantages over traditional approaches for cost, efficiency, and simplicity.

  7. Process Parameter Optimization of Extrusion-Based 3D Metal Printing Utilizing PW–LDPE–SA Binder System

    Directory of Open Access Journals (Sweden)

    Luquan Ren

    2017-03-01

    Full Text Available Recently, with a broadening range of available materials and alteration of feeding processes, several extrusion-based 3D printing processes for metal materials have been developed. An emerging process is applicable for the fabrication of metal parts into electronics and composites. In this paper, some critical parameters of extrusion-based 3D printing processes were optimized by a series of experiments with a melting extrusion printer. The raw materials were copper powder and a thermoplastic organic binder system and the system included paraffin wax, low density polyethylene, and stearic acid (PW–LDPE–SA. The homogeneity and rheological behaviour of the raw materials, the strength of the green samples, and the hardness of the sintered samples were investigated. Moreover, the printing and sintering parameters were optimized with an orthogonal design method. The influence factors in regard to the ultimate tensile strength of the green samples can be described as follows: infill degree > raster angle > layer thickness. As for the sintering process, the major factor on hardness is sintering temperature, followed by holding time and heating rate. The highest hardness of the sintered samples was very close to the average hardness of commercially pure copper material. Generally, the extrusion-based printing process for producing metal materials is a promising strategy because it has some advantages over traditional approaches for cost, efficiency, and simplicity.

  8. Process Parameter Optimization of Extrusion-Based 3D Metal Printing Utilizing PW–LDPE–SA Binder System

    Science.gov (United States)

    Ren, Luquan; Zhou, Xueli; Song, Zhengyi; Zhao, Che; Liu, Qingping; Xue, Jingze; Li, Xiujuan

    2017-01-01

    Recently, with a broadening range of available materials and alteration of feeding processes, several extrusion-based 3D printing processes for metal materials have been developed. An emerging process is applicable for the fabrication of metal parts into electronics and composites. In this paper, some critical parameters of extrusion-based 3D printing processes were optimized by a series of experiments with a melting extrusion printer. The raw materials were copper powder and a thermoplastic organic binder system and the system included paraffin wax, low density polyethylene, and stearic acid (PW–LDPE–SA). The homogeneity and rheological behaviour of the raw materials, the strength of the green samples, and the hardness of the sintered samples were investigated. Moreover, the printing and sintering parameters were optimized with an orthogonal design method. The influence factors in regard to the ultimate tensile strength of the green samples can be described as follows: infill degree > raster angle > layer thickness. As for the sintering process, the major factor on hardness is sintering temperature, followed by holding time and heating rate. The highest hardness of the sintered samples was very close to the average hardness of commercially pure copper material. Generally, the extrusion-based printing process for producing metal materials is a promising strategy because it has some advantages over traditional approaches for cost, efficiency, and simplicity. PMID:28772665

  9. Heavy Metals in Notifications of Rapid Alert System for Food and Feed

    Science.gov (United States)

    Pigłowski, Marcin

    2018-01-01

    Heavy metals represent the fourth most often notified hazard category in the Rapid Alert System for Food and Feed (RASFF) from 1980–2016. The goal of the study was to examine the similarities in notifications of particular heavy metals within the RASFF year, product category, notifying country, country of origin, notification basis, notification type, distribution status, risk decision, and action taken, taking into account the particular product type, such as food, food contact material, and feed. The data originated from the RASFF database. Cluster analysis on pivot tables was applied using joining and two-way joining methods. Most notifications concerned food, in which the highest number were related to mercury, cadmium, chromium, lead, arsenic, and nickel. Notifications were mainly related to fish and food contact materials, in addition to fruits and vegetables, seafood, and dietetic food. The number of notifications decreased in 2015 and 2016. The majority of products were notified by Italy, Spain, Germany, and France. The notified products originated mainly from China and Spain. The notification was usually based on official controls on the market, as well as border controls. The notification types were mainly information, alert, and border rejections. Products were not frequently distributed due to distribution restriction to the notifying country or the possibility of distribution to the market. A risk decision was not usually made. The taken actions included re-dispatch of products, withdrawal from the market, or destruction. The data on heavy metals from the RASFF database can help European and national authorities in shaping public health. PMID:29461471

  10. Heavy Metals in Notifications of Rapid Alert System for Food and Feed

    Directory of Open Access Journals (Sweden)

    Marcin Pigłowski

    2018-02-01

    Full Text Available Heavy metals represent the fourth most often notified hazard category in the Rapid Alert System for Food and Feed (RASFF from 1980–2016. The goal of the study was to examine the similarities in notifications of particular heavy metals within the RASFF year, product category, notifying country, country of origin, notification basis, notification type, distribution status, risk decision, and action taken, taking into account the particular product type, such as food, food contact material, and feed. The data originated from the RASFF database. Cluster analysis on pivot tables was applied using joining and two-way joining methods. Most notifications concerned food, in which the highest number were related to mercury, cadmium, chromium, lead, arsenic, and nickel. Notifications were mainly related to fish and food contact materials, in addition to fruits and vegetables, seafood, and dietetic food. The number of notifications decreased in 2015 and 2016. The majority of products were notified by Italy, Spain, Germany, and France. The notified products originated mainly from China and Spain. The notification was usually based on official controls on the market, as well as border controls. The notification types were mainly information, alert, and border rejections. Products were not frequently distributed due to distribution restriction to the notifying country or the possibility of distribution to the market. A risk decision was not usually made. The taken actions included re-dispatch of products, withdrawal from the market, or destruction. The data on heavy metals from the RASFF database can help European and national authorities in shaping public health.

  11. Partitioning planning studies: Preliminary evaluation of metal and radionuclide partitioning the high-temperature thermal treatment systems

    International Nuclear Information System (INIS)

    Liekhus, K.; Grandy, J.; Chambers, A.

    1997-03-01

    A preliminary study of toxic metals and radionuclide partitioning during high-temperature processing of mixed waste has been conducted during Fiscal Year 1996 within the Environmental Management Technology Evaluation Project. The study included: (a) identification of relevant partitioning mechanisms that cause feed material to be distributed between the solid, molten, and gas phases within a thermal treatment system; (b) evaluations of existing test data from applicable demonstration test programs as a means to identify and understand elemental and species partitioning; and, (c) evaluation of theoretical or empirical partitioning models for use in predicting elemental or species partitioning in a thermal treatment system. This preliminary study was conducted to identify the need for and the viability of developing the tools capable of describing and predicting toxic metals and radionuclide partitioning in the most applicable mixed waste thermal treatment processes. This document presents the results and recommendations resulting from this study that may serve as an impetus for developing and implementing these predictive tools

  12. Partitioning planning studies: Preliminary evaluation of metal and radionuclide partitioning the high-temperature thermal treatment systems

    Energy Technology Data Exchange (ETDEWEB)

    Liekhus, K.; Grandy, J.; Chambers, A. [and others

    1997-03-01

    A preliminary study of toxic metals and radionuclide partitioning during high-temperature processing of mixed waste has been conducted during Fiscal Year 1996 within the Environmental Management Technology Evaluation Project. The study included: (a) identification of relevant partitioning mechanisms that cause feed material to be distributed between the solid, molten, and gas phases within a thermal treatment system; (b) evaluations of existing test data from applicable demonstration test programs as a means to identify and understand elemental and species partitioning; and, (c) evaluation of theoretical or empirical partitioning models for use in predicting elemental or species partitioning in a thermal treatment system. This preliminary study was conducted to identify the need for and the viability of developing the tools capable of describing and predicting toxic metals and radionuclide partitioning in the most applicable mixed waste thermal treatment processes. This document presents the results and recommendations resulting from this study that may serve as an impetus for developing and implementing these predictive tools.

  13. Alkali Metal Backup Cooling for Stirling Systems - Experimental Results

    Science.gov (United States)

    Schwendeman, Carl; Tarau, Calin; Anderson, William G.; Cornell, Peggy A.

    2013-01-01

    In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor. In a previous NASA SBIR Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for Stirling RPS. The operation of these VCHPs was demonstrated using Stirling heater head simulators and GPHS simulators. In the most recent effort, a sodium VCHP with a stainless steel envelope was designed, fabricated and tested at NASA Glenn Research Center (GRC) with a Stirling convertor for two concepts; one for the Advanced Stirling Radioisotope Generator (ASRG) back up cooling system and one for the Long-lived Venus Lander thermal management system. The VCHP is designed to activate and remove heat from the stopped convertor at a 19 degC temperature increase from the nominal vapor temperature. The 19 degC temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the Multi-Layer Insulation (MLI). In addition, the same backup cooling system can be applied to the Stirling convertor used for the refrigeration system of the Long-lived Venus Lander. The VCHP will allow the refrigeration system to: 1) rest during transit at a lower temperature than nominal; 2) pre-cool the modules to an even lower temperature before the entry in Venus atmosphere; 3) work at nominal temperature on Venus surface; 4) briefly stop multiple times on the Venus surface to allow scientific measurements. This paper presents the experimental

  14. Heavy metal removal in an UASB-CW system treating municipal wastewater.

    Science.gov (United States)

    de la Varga, D; Díaz, M A; Ruiz, I; Soto, M

    2013-10-01

    The objective of the present study was to investigate for the first time the long-term removal of heavy metals (HMs) in a combined UASB-CW system treating municipal wastewater. The research was carried out in a field pilot plant constituted for an up-flow anaerobic sludge bed (UASB) digester as a pretreatment, followed by a surface flow constructed wetland (CW) and finally by a subsurface flow CW. While the UASB showed (pseudo) steady state operational conditions and generated a periodical purge of sludge, CWs were characterised by the progressive accumulation and mineralisation of retained solids. This paper analyses the evolution of HM removal from the water stream over time (over a period of 4.7 year of operation) and the accumulation of HMs in UASB sludge and CW sediments at two horizons of 2.7 and 4.0 year of operation. High removal efficiencies were found for some metals in the following order: Sn > Cr > Cu > Pb > Zn > Fe (63-94%). Medium removal efficiencies were registered for Ni (49%), Hg (42%), and Ag (40%), and finally Mn and As showed negative percentage removals. Removal efficiencies of total HMs were higher in UASB and SF units and lower in the last SSF unit. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Metal-ion retention properties of water-soluble amphiphilic block copolymer in double emulsion systems (w/o/w) stabilized by non-ionic surfactants.

    Science.gov (United States)

    Palencia, Manuel; Rivas, Bernabé L

    2011-11-15

    Metal-ion retention properties of water-soluble amphiphilic polymers in presence of double emulsion were studied by diafiltration. Double emulsion systems, water-in-oil-in-water, with a pH gradient between external and internal aqueous phases were prepared. A poly(styrene-co-maleic anhydride) (PSAM) solution at pH 6.0 was added to the external aqueous phase of double emulsion and by application of pressure a divalent metal-ion stream was continuously added. Metal-ions used were Cu(2+) and Cd(2+) at the same pH of polymer solution. According to our results, metal-ion retention is mainly the result of polymer-metal interaction. Interaction between PSMA and reverse emulsion globules is strongly controlled by amount of metal-ions added in the external aqueous phase. In addition, as metal-ion concentration was increased, a negative effect on polymer retention capacity and promotion of flocculation phenomena were produced. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Plant responses to metal toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Briat, J.F. [Montpellier-2 Univ., 34 (France). Biochimie et physiologie moleculaire des plantes, CNRS, URA 2133; Lebrun, M. [Montpellier-2 Univ., 34 (France). Biochimie et physiologie vegetale appliquee

    1999-01-01

    Increased metal concentration in the soils, up to toxic levels, is becoming an important environmental problem. Safety rule evolution will require solutions in order to cope with food safety rules, and to freeze metal leakage from heavily metal-poisoned soils, such as those from industrial fallows. In this context, plants could serve to develop bio-assays in order to promote new standards, more realistic than the mass of a given metal per kg of soil, that does not consider the metal bio-disponibility. Plants could also be used for phyto-extraction and/or phyto-stabilization. To reach these objectives, a genetic approach could be useful to generate metal-tolerant plants with enough biomass. In this work is more particularly studied the plant responses to metal toxicity. Metal toxicity for living organisms involves oxidative and /or genotoxic mechanisms. Plant protection against metal toxicity occurs, at least in part, through control of root metal uptake and of long distance metal transport. Inside cells, proteins such as ferritins and metallothioneins, and glutathione-derived peptides named phyto-chelatins, participate in excess metal storage and detoxification. Low molecular weight organic molecules, mainly organic acids and amino acids and their derivatives, also play an important role in plant metal homeostasis. When these systems are overloaded, oxidative stress defense mechanisms are activated. Molecular and cellular knowledge of these processes will be necessary to improve plant metal resistance. Occurrence of naturally tolerant plants which hyper accumulate metals provides helpful tools for this research. (authors) 130 refs.

  17. FY 1998 report on the result of R and D projects by local consortiums. Rare metal recovery and resourcing of residual slags from metal plating wastes and aluminum dross by continuous thermit reaction (CTR) system; 1998 nendo CTR (Continuous Termit Reaction) System ni yoru aluminium dross to mekki surajji kara no energy less, rare metal kaisei process to sono slag no saishigenka seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    The R and D project has been implemented for treating metal plating wastes (sludge) and aluminum dross in a melting furnace operated in a reducing atmosphere, in order to make the wastes harmless and recover the rare metals by the thermit reactions. The theoretical analysis of the powder properties has produced the desired powder pretreatment conditions, such as drying/firing conditions, mixing ratio and composition, forming conditions, and characteristics of the formed articles. For recovering the useful metals, it is confirmed that the thermit reactions proceed efficiently in a high-temperature melting furnace operated in a reducing atmosphere, and the molten metals are easily separated from the molten slag. It is also confirmed that the formed article allows separation of the metals from the residual slag more easily than the mixed powder. For the design of the continuous thermit reaction (CTR) system, it is investigated whether the products and other discharged substances can be safely handled and effectively utilized, and the control/instrumentation systems and others are established after setting the conditions for, e.g., sludge drying/firing in air, powder mixing/crushing, briquette production, and flow of the thermit reactions in a reducing atmosphere. (NEDO)

  18. Hydrogen storage evaluation based on investigations of the catalytic properties of metal/metal oxides in electrospun carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Im, Ji Sun; Lee, Young-Seak [Department of Fine Chemical Engineering and Chemistry, Chungnam National University, Daejeon 305-764 (Korea); Park, Soo-Jin [Department of Chemistry, Inha University, Incheon 402-751 (Korea); Kim, Taejin [Core Technology Research Center for Fuel Cell, Jeollabuk-do 561-844 (Korea)

    2009-05-15

    In order to investigate the catalytic capacity of metals and metal oxides based on electrospun carbon fibers for improving hydrogen storage, electrospinning and heat treatments were carried out to obtain metal/metal oxide-embedded carbon fibers. Although the fibers were treated with the same activation procedure, they had different pore structures, due to the nature of the metal oxide. When comparing the catalytic capacity of metal and metal oxide, metal exhibits better performance as a catalyst for the improvement of hydrogen storage, when considering the hydrogen storage system. When a metal oxide with an m.p. lower than the temperature of heat treatment was used, the metal oxide was changed to metal during the heat treatment, developing a micropore structure. The activation process produced a high specific surface area of up to 2900 m{sup 2}/g and a pore volume of up to 2.5 cc/g. The amount of hydrogen adsorption reached approximately 3 wt% at 100 bar and room temperature. (author)

  19. Metal resistance or tolerance? Acidophiles confront high metal loads via both abiotic and biotic mechanisms

    Directory of Open Access Journals (Sweden)

    Mark eDopson

    2014-04-01

    Full Text Available All metals are toxic at high concentrations and consequently their intracellular concentrations must be regulated. Acidophilic microorganisms have an optimum growth pH < 3 and proliferate in natural and anthropogenic low pH environments. Some acidophiles are involved in the catalysis of sulfide mineral dissolution, resulting in high concentrations of metals in solution. Acidophiles are often described as highly metal resistant via mechanisms such as multiple and/or more efficient active resistance systems than are present in neutrophiles. However, this is not the case for all acidophiles and we contend that their growth in high metal concentrations is partially due to an intrinsic tolerance as a consequence of the environment in which they live. In this perspective, we highlight metal tolerance via complexation of free metals by sulfate ions and passive tolerance to metal influx via an internal positive cytoplasmic transmembrane potential. These tolerance mechanisms have been largely ignored in past studies of acidophile growth in the presence of metals and should be taken into account.

  20. Emerging Science and Research Opportunities for Metals and Metallic Nanostructures

    Science.gov (United States)

    Handwerker, Carol A.; Pollock, Tresa M.

    2014-07-01

    During the next decade, fundamental research on metals and metallic nanostructures (MMNs) has the potential to continue transforming metals science into innovative materials, devices, and systems. A workshop to identify emerging and potentially transformative research areas in MMNs was held June 13 and 14, 2012, at the University of California Santa Barbara. There were 47 attendees at the workshop (listed in the Acknowledgements section), representing a broad range of academic institutions, industry, and government laboratories. The metals and metallic nanostructures (MMNs) workshop aimed to identify significant research trends, scientific fundamentals, and recent breakthroughs that can enable new or enhanced MMN performance, either alone or in a more complex materials system, for a wide range of applications. Additionally, the role that MMN research can play in high-priority research and development (R&D) areas such as the U.S. Materials Genome Initiative, the National Nanotechnology Initiative, the Advanced Manufacturing Initiative, and other similar initiatives that exist internationally was assessed. The workshop also addressed critical issues related to materials research instrumentation and the cyberinfrastructure for materials science research and education, as well as science, technology, engineering, and mathematics (STEM) workforce development, with emphasis on the United States but with an appreciation that similar challenges and opportunities for the materials community exist internationally. A central theme of the workshop was that research in MMNs has provided and will continue to provide societal benefits through the integration of experiment, theory, and simulation to link atomistic, nanoscale, microscale, and mesoscale phenomena across time scales for an ever-widening range of applications. Within this overarching theme, the workshop participants identified emerging research opportunities that are categorized and described in more detail in the

  1. 33 CFR 183.562 - Metallic fuel lines.

    Science.gov (United States)

    2010-07-01

    ...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Manufacturer Requirements § 183.562 Metallic fuel lines. (a) Each metallic fuel line that is mounted to the boat structure must be connected to the engine by a flexible fuel line. (b) Each metallic fuel line must be attached to the boat's structure...

  2. Quinonoid metal complexes: toward molecular switches.

    Science.gov (United States)

    Dei, Andrea; Gatteschi, Dante; Sangregorio, Claudio; Sorace, Lorenzo

    2004-11-01

    The peculiar redox-active character of quinonoid metal complexes makes them extremely appealing to design materials of potential technological interest. We show here how the tuning of the properties of these systems can be pursued by using appropriate molecular synthetic techniques. In particular, we focus our attention on metal polyoxolene complexes exhibiting intramolecular electron transfer processes involving either the ligand and the metal ion or the two dioxolene moieties of a properly designed ligand thus inducing electronic bistability. The transition between the two metastable electronic states can be induced by different external stimuli such as temperature, pressure, light, or pH suggesting the use of these systems for molecular switches.

  3. In-situ ductile metal/bulk metallic glass matrix composites formed by chemical partitioning

    Science.gov (United States)

    Kim, Choong Paul; Hays, Charles C.; Johnson, William L.

    2004-03-23

    A composite metal object comprises ductile crystalline metal particles in an amorphous metal matrix. An alloy is heated above its liquidus temperature. Upon cooling from the high temperature melt, the alloy chemically partitions, forming dendrites in the melt. Upon cooling the remaining liquid below the glass transition temperature it freezes to the amorphous state, producing a two-phase microstructure containing crystalline particles in an amorphous metal matrix. The ductile metal particles have a size in the range of from 0.1 to 15 micrometers and spacing in the range of from 0.1 to 20 micrometers. Preferably, the particle size is in the range of from 0.5 to 8 micrometers and spacing is in the range of from 1 to 10 micrometers. The volume proportion of particles is in the range of from 5 to 50% and preferably 15 to 35%. Differential cooling can produce oriented dendrites of ductile metal phase in an amorphous matrix. Examples are given in the Zr--Ti--Cu--Ni--Be alloy bulk glass forming system with added niobium.

  4. Preliminary Criticality Calculation on Conceptual Deep Borehole Disposal System for Trans-metal Waste during Operational Phase

    International Nuclear Information System (INIS)

    Kim, In Young; Choi, Heui Joo; Cho, Dong Geun

    2013-01-01

    The primary function of any repository is to prevent spreading of dangerous materials into surrounding environment. In the case of high-level radioactive waste repository, radioactive material must be isolated and retarded during sufficient decay time to minimize radiation hazard to human and surrounding environment. Sub-criticality of disposal canister and whole disposal system is minimum requisite to prevent multiplication of radiation hazard. In this study, criticality of disposal canister and DBD system for trans-metal waste is calculated to check compliance of sub-criticality. Preliminary calculation on criticality of conceptual deep borehole disposal system and its canister for trans-metal waste during operational phase is conducted in this study. Calculated criticalities at every temperature are under sub-criticalities and criticalities of canister and DBD system considering temperature are expected to become 0.34932 and 0.37618 approximately. There are obvious limitations in this study. To obtain reliable data, exact elementary composition of each component, system component temperature must be specified and applied, and then proper cross section according to each component temperature must be adopted. However, many assumptions, for example simplified elementary concentration and isothermal component temperature, are adopted in this study. Improvement of these data must be conducted in the future work to progress reliability. And, post closure criticality analyses including geo, thermal, hydro, mechanical, chemical mechanism, especially fissile material re-deposition by precipitation and sorption, must be considered to ascertain criticality safety of DBD system as a future work

  5. Method of producing homogeneous mixed metal oxides and metal-metal oxide mixtures

    International Nuclear Information System (INIS)

    Quinby, T.C.

    1980-01-01

    A method for preparing particulate metal or metal oxide of controlled partile size comprises contacting an an aqueous solution containing dissolved metal values with excess urea at a temperature sufficient to cause urea to react with water to provide a molten urea solution containing the metal values; heating the molten urea solution to cause the metal values to precipitate, forming a mixture containing precipitated metal values; heating the mixture containing precipitated metal values to evaporate volatile material leaving a dry powder containing said metal values. The dry powder can be calcined to provide particulate metal oxide or reduced to provide particulate metal. Oxide mixtures are provided when the aqueous solution contains values of more than one metal. Homogeneousmetal-metal oxide mistures for preparing cermets can be prepared by selectively reducing at least one of the metal oxides. (auth)

  6. Process for the enhanced capture of heavy metal emissions

    Science.gov (United States)

    Biswas, Pratim; Wu, Chang-Yu

    2001-01-01

    This invention is directed to a process for forming a sorbent-metal complex. The process includes oxidizing a sorbent precursor and contacting the sorbent precursor with a metallic species. The process further includes chemically reacting the sorbent precursor and the metallic species, thereby forming a sorbent-metal complex. In one particular aspect of the invention, at least a portion of the sorbent precursor is transformed into sorbent particles during the oxidation step. These sorbent particles then are contacted with the metallic species and chemically reacted with the metallic species, thereby forming a sorbent-metal complex. Another aspect of the invention is directed to a process for forming a sorbent metal complex in a combustion system. The process includes introducing a sorbent precursor into a combustion system and subjecting the sorbent precursor to an elevated temperature sufficient to oxidize the sorbent precursor and transform the sorbent precursor into sorbent particles. The process further includes contacting the sorbent particles with a metallic species and exposing the sorbent particles and the metallic species to a complex-forming temperature whereby the metallic species reacts with the sorbent particles thereby forming a sorbent-metal complex under UV irradiation.

  7. Role of calcium-depositing bacteria Agrobacterium tumefaciens and its influence on corrosion of different engineering metals used in cooling water system.

    Science.gov (United States)

    Narenkumar, Jayaraman; Sathishkumar, Kuppusamy; Selvi, Adikesavan; Gobinath, Rajagopalan; Murugan, Kadarkarai; Rajasekar, Aruliah

    2017-12-01

    The present investigation deals with the role of calcium-depositing bacterial community on corrosion of various engineering metals, namely, brass alloy (BS), copper (Cu), stainless steel (SS) and mild steel (MS). Based on the corrosion behavior, Agrobacterium tumefaciens EN13, an aerobic bacterium is identified as calcium-depositing bacteria on engineering metals. The results of the study are supported with biochemical characterization, 16S rRNA gene sequencing, calcium quantification, weight loss, electrochemical (impedance and polarization) and surface analysis (XRD and FTIR) studies. The calcium quantification study showed carbonate precipitation in abiotic system/biotic system as 50 and 700 ppm, respectively. FTIR results too confirmed the accumulation of calcium deposits from the environment on the metal surface by EN13. Electrochemical studies too supported the corrosion mechanism by showing a significant increase in the charge transfer resistance ( R ct ) of abiotic system (44, 33.6, 45, 29.6 Ω cm 2 ) than compared to biotic system (41, 10.1 29 and 25 Ω cm 2 ). Hence, the outcome of the present study confirmed the enhanced bioaccumulation behavior of calcium by the strain, EN13.

  8. Structure and properties of transition metal-metalloid glasses based on refractory metals

    International Nuclear Information System (INIS)

    Johnson, W.L.; Williams, A.R.

    1979-01-01

    The structure and properties of several new transition metal-metalloid (TM/sub 1-x/M/sub x/) metallic glasses based on refractory transition metals (e.g. Mo, W, Ru etc.) have been systemically investigated as a function of composition. The structure of the alloys has been investigated by x-ray diffraction methods and measurements of superconducting properties, electrical resistivity, density, hardness, and mechanical behavior were made. These data are used in developing a novel description of the structure of TM/sub 1-x/M/sub x/ glasses. The experimental evidence suggests that an ideal amorphous phase forms at a specific composition x/sub c/ and that this phase has a well defined atomic short range order. For metallic glasses having x x/sub c/. This novel picture can explain the variation of many properties of these glasses with metalloid concentration

  9. Transfer and mobility of trace metallic elements in the sedimentary column of continental hydro-systems

    International Nuclear Information System (INIS)

    Devallois, V.

    2009-02-01

    In freshwater systems, trace metal pollutants are transferred into water and sedimentary columns under dissolved forms and/or fixed onto solid particles. Accumulated in the sedimentary areas, these latter ones can constitute important stocks of materials and associated pollutants and may impair water quality when environmental changes lead to increase their mobility. The mobility of the stocks of pollutants is mainly depending on the erosion, on the interstitial diffusion of the mobile phases (dissolved and colloidal) and on the bioturbation. In this context, this study involves the analysis of the mobility by interstitial diffusion. This topic consists in studying trace metal fractionation between their mobile (dissolved and colloidal) and non mobile (fixed onto the particles) forms. This point is governed by sorption/desorption processes at the particle surfaces. These processes are regulated by physico-chemical parameters (pH, redox potential, ionic strength...) and are influenced by biogeochemical reactions resulting from the oxidation of the organic matter by the microbial activity. These reactions generate vertical profiles of nutrients and metal concentrations along the sedimentary column. To understand these processes, this work is based on a mixed approach that combines in situ, analysis and modelling. In situ experimental part consists in sampling natural sediments cores collected at 4 different sites (1 site in Durance and 3 sites on the Rhone). These samples are analyzed according to an analytical protocol that provides the vertical distribution of physicochemical parameters (pH, redox potential, size distribution, porosity), nutrients and solid - liquid forms of trace metals (cobalt, copper, nickel, lead, zinc). The analysis and interpretation of these experimental results are based on a model that was developed during this study and that includes: 1) model of interstitial diffusion (Boudreau, 1997), 2) biogeochemical model (Wang and Van Cappellen

  10. Aquatic macrophytes as indicators of heavy metal pollution of water in DTD canal system

    Directory of Open Access Journals (Sweden)

    Pajević Slobodanka P.

    2003-01-01

    Full Text Available The aim of this investigation was to establish the presence or absence of chemical contamination of water and the littoral zone (banks of Danube-Tisza-Danube (DTD canal system. The investigation covered the canal section from Bezdan to Prigrevica. By analyzing the chemical composition of dominant aquatic species in four locations of the section, we defined the species with the highest capacity to accumulate nutrients and heavy metals. Concentrations of P and K as well as of a beneficial element Na in the tissues of the analyzed macrophytes were both species- and site-dependent. The highest accumulation was registered for Ceratophyllum demersum while the species Elodea canadensis showed increased P and K accumulation values in the location Sombor. The lowest concentrations of almost all heavy metals were recorded near Sombor, indicating that this section suffered the lowest chemical pollution. Highest concentrations of all of the analyzed heavy metals were recorded in the tissue of Ceratophyllum demersum from the location Prigrevica, possibly due to the influx of polluted drainage waters from surrounding agricultural areas as well as industrial wastewaters. The obtained results showed that the enforcement of biomonitoring and analyses of other parameters indicative of ecosystem conditions might be useful for improved protection of areas experiencing a strong human impact.

  11. Synthesis and characterization of some reduced ternary and quaternary molybdenum oxide phases with strong metal-metal bonds

    International Nuclear Information System (INIS)

    Lii, K.H.

    1985-10-01

    In the course of our research on reduced ternary and quaternary molybdenum oxides, very interesting compounds with strong metal-metal bonds were discovered. Among these solid-state materials are found discrete cluster arrays and structures with extended metal-metal bonding. Further study in this system has revealed that many new structures exist in this new realm. The synthesis, structures, bonding, and properties of these new oxides, which are briefly summarized in tabular form, are presented in this thesis. 144 refs., 63 figs., 79 tabs

  12. Method of producing homogeneous mixed metal oxides and metal--metal oxide mixtures

    International Nuclear Information System (INIS)

    Quinby, T.C.

    1978-01-01

    Metal powders, metal oxide powders, and mixtures thereof of controlled particle size are provided by reacting an aqueous solution containing dissolved metal values with excess urea. Upon heating, urea reacts with water from the solution to leave a molten urea solution containing the metal values. The molten urea solution is heated to above about 180 0 C, whereupon metal values precipitate homogeneously as a powder. The powder is reduced to metal or calcined to form oxide particles. One or more metal oxides in a mixture can be selectively reduced to produce metal particles or a mixture of metal and metal oxide particles

  13. Performance analysis of a membrane humidifier containing porous metal foam as flow distributor in a PEM fuel cell system

    International Nuclear Information System (INIS)

    Afshari, Ebrahim; Baharlou Houreh, Nasser

    2014-01-01

    Highlights: • Three metal foam configurations for the membrane humidifier are introduced. • The performances of the humidifiers containing metal foam are investigated. • A 3D CFD model is developed to compare the introduced humidifiers with one another. • Using metal foam at dry side has no positive effect on the humidifier performance. - Abstract: Using metal foam as flow distributor in membrane humidifier for proton exchange membrane (PEM) fuel cell system has some unique characteristics like more water transfer, low manufacturing complexity and low cost compared to the conventional flow channel plate. Metal foam can be applied at wet side or dry side or both sides of a humidifier. The three-dimensional CFD models are developed to investigate the performance of the above mentioned meanwhile compare them with the conventional humidifier. This model consists of a set of coupled equations including conservations of mass, momentum, species and energy for all regions of the humidifier. The results indicate that with the metal foam installed at wet side and both sides, water recovery ratio and dew point at dry side outlet are more than that of the conventional humidifier, indicating a better humidifier performance; while using metal foam at dry side has no positive effect on humidifier performance. At dry side mass flow rates higher than 10 mgr/s pressure drop in humidifier containing metal foam at wet side is lower than that of the conventional humidifier. As the mass flow rate increases from 9 to 15 mgr/s humidifier containing metal foam at wet side has better performance, while at mass flow rates lower than 9 mgr/s, the humidifier containing metal foam at both sides has better performance. At dry side inlet temperatures lower than 303 K, humidifier containing metal foam at wet side has better performance and at temperatures higher than 303 K, humidifier containing metal foam at both sides has better performance

  14. Synthesis of uranium metal using laser-initiated reduction of uranium tetrafluoride by calcium metal

    International Nuclear Information System (INIS)

    West, M.H.; Martinez, M.M.; Nielsen, J.B.; Court, D.C.; Appert, Q.D.

    1995-09-01

    Uranium metal has numerous uses in conventional weapons (armor penetrators) and nuclear weapons. It also has application to nuclear reactor designs utilizing metallic fuels--for example, the former Integral Fast Reactor program at Argonne National Laboratory. Uranium metal also has promise as a material of construction for spent-nuclear-fuel storage casks. A new avenue for the production of uranium metal is presented that offers several advantages over existing technology. A carbon dioxide (CO 2 ) laser is used to initiate the reaction between uranium tetrafluoride (UF 4 ) and calcium metal. The new method does not require induction heating of a closed system (a pressure vessel) nor does it utilize iodine (I 2 ) as a chemical booster. The results of five reductions of UF 4 , spanning 100 to 200 g of uranium, are evaluated, and suggestions are made for future work in this area

  15. Testing new tribo-systems for sheet metal forming of advanced high strength steels and stainless steels

    DEFF Research Database (Denmark)

    Bay, Niels; Ceron, Ermanno

    2014-01-01

    of a methodology for off-line testing of new tribo-systems for advanced high strength steels and stainless steels. The methodology is presented and applied to an industrial case, where different tribo-systems are tested. A universal sheet tribotester has been developed, which can run automatically repetitive......Testing of new tribo-systems in sheet metal forming has become an important issue due to new legislation, which forces industry to replace current, hazardous lubricants. The present paper summarizes the work done in a recent PhD project at the Technical University of Denmark on the development...

  16. Metal Abundances at z<1.5: Fresh Clues to the Chemical Enrichment History of Damped Lyα Systems

    Science.gov (United States)

    Pettini, Max; Ellison, Sara L.; Steidel, Charles C.; Bowen, David V.

    1999-01-01

    We explore the redshift evolution of the metal content of damped Lyα systems (DLAs) with new observations of four absorbers at zintermediate redshifts for which the abundance of Zn has been measured. The main conclusion is that the column density-weighted mean metallicity, []=-1.03+/-0.23 (on a logarithmic scale), is not significantly higher at zaccounted for, leaves no room for the enhancement of the α elements over iron seen in metal-poor stars in the Milky Way. This is contrary to previous assertions that DLAs have been enriched solely by Type II supernovae, but it can be understood if the rate of star formation in the systems studied proceeded more slowly than in the early history of our Galaxy. These results add to a growing body of data pointing to the conclusion that known DLAs do not trace the galaxy population responsible for the bulk of star formation. Possible reasons are that sight lines through metal-rich gas are systematically underrepresented, because the background QSOs are reddened, and that the most actively star-forming galaxies are also the most compact, presenting too small a cross-section to have been probed yet with the limited statistics of current samples. Most of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among Caltech, the University of California, and NASA. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  17. Disintegration and size reduction of slags and metals after melt refining of contaminated metallic wastes

    International Nuclear Information System (INIS)

    Heshmatpour, B.; Copeland, G.L.; Heestand, R.L.

    1981-04-01

    Melting under an oxidizing slag is an attractive method of decontaminating and reducing the volume of radioactively contaminated metal scrap. The contaminants are concentrated in a relatively small volume of slag, which leaves the metal essentially clean. A potential method of permanently disposing of the resulting slags (and metals if necessary) is emplacing them into deep shale by grout hydrofracture. Suspension in grout mixtures requires that the slag and metal be granular. The feasibility of size-reducing slags and disintegrating metals and subsequently incorporating both into grout mixtures was demonstrated. Various types of slags were crushed with a small jaw crusher into particles smaller than 3 mm. Several metals were also melted and water-blasted into coarse metal powder or shot ranging in size from 0.05 to 3 mm. A simple low-pressure water atomizer having a multiple nozzle with a converging-line jet stream was developed and used for this purpose. No significant slag dust and steam were generated during slag crushing and liquid-metal water-blasting tests, indicating that contamination can be well contained within the system. The crushed slags and the coarse metal powders were suspendable in group fluids, which indicates probable disposability by shale hydrofracture. The granulation of slags and metals facilitates their containment, transport, and storage

  18. A novel bioreactor system for simultaneous mutli-metal leaching from industrial pyrite ash: Effect of agitation and sulphur dosage.

    Science.gov (United States)

    Panda, Sandeep; Akcil, Ata; Mishra, Srabani; Erust, Ceren

    2018-01-15

    Simultaneous multi-metal leaching from industrial pyrite ash is reported for the first time using a novel bioreactor system that allows natural diffusion of atmospheric O 2 and CO 2 along with the required temperature maintenance. The waste containing economically important metals (Cu, Co, Zn & As) was leached using an adapted consortium of meso-acidophilic Fe 2+ and S oxidising bacteria. The unique property of the sample supported adequate growth and activity of the acidophiles, thereby, driving the (bio) chemical reactions. Oxido-reductive potentials were seen to improve with time and the system's pH lowered as a result of active S oxidation. Increase in sulphur dosage (>1g/L) and agitation speed (>150rpm) did not bear any significant effect on metal dissolution. The consortium was able to leach 94.01% Cu (11.75% dissolution/d), 98.54% Co (12.3% dissolution/d), 75.95% Zn (9.49% dissolution/d) and 60.80% As (7.6% dissolution/d) at 150rpm, 1g/L sulphur, 30°C in 8days. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Electrical Matching at Metal/Molecule Contacts for Efficient Heterogeneous Charge Transfer.

    Science.gov (United States)

    Sato, Shino; Iwase, Shigeru; Namba, Kotaro; Ono, Tomoya; Hara, Kenji; Fukuoka, Atsushi; Uosaki, Kohei; Ikeda, Katsuyoshi

    2018-02-27

    In a metal/molecule hybrid system, unavoidable electrical mismatch exists between metal continuum states and frontier molecular orbitals. This causes energy loss in the electron conduction across the metal/molecule interface. For efficient use of energy in a metal/molecule hybrid system, it is necessary to control interfacial electronic structures. Here we demonstrate that electrical matching between a gold substrate and π-conjugated molecular wires can be obtained by using monatomic foreign metal interlayers, which can change the degree of d-π* back-donation at metal/anchor contacts. This interfacial control leads to energy level alignment between the Fermi level of the metal electrode and conduction molecular orbitals, resulting in resonant electron conduction in the metal/molecule hybrid system. When this method is applied to molecule-modified electrocatalysts, the heterogeneous electrochemical reaction rate is considerably improved with significant suppression of energy loss at the internal electron conduction.

  20. Chemical effects in ion mixing of a ternary system (metal-SiO2)

    Science.gov (United States)

    Banwell, T.; Nicolet, M.-A.; Sands, T.; Grunthaner, P. J.

    1987-01-01

    The mixing of Ti, Cr, and Ni thin films with SiO2 by low-temperature (- 196-25 C) irradiation with 290 keV Xe has been investigated. Comparison of the morphology of the intermixed region and the dose dependences of net metal transport into SiO2 reveals that long range motion and phase formation probably occur as separate and sequential processes. Kinetic limitations suppress chemical effects in these systems during the initial transport process. Chemical interactions influence the subsequent phase formation.

  1. Various aspects of ionic machining applied to metallic systems in microwave dipolar transistors

    International Nuclear Information System (INIS)

    Pestie, J.P.; Dumontet, H.; Andrieu, J.P.

    1974-01-01

    The positive benefit of ion bombardment machining in fabricating bipolar microwave transistors is shown. Ion cleaning, especially for P type silicon with high boron concentration allows reproducible surface resistivities to be reached 10 -6 ohms/cm 2 ) and the spurious resistance of the basis to be minimized. Ionic etching of metallic layers allowed 1μm stepped geometric structures to be realized. The multilayer Ti-Pt-Au system was associated to the finest geometries through a finite number of operations [fr

  2. Countercurrent soil washing system for remediation of viscous hydrocarbons, heavy metals, radionuclides

    International Nuclear Information System (INIS)

    Kuhlman, M.I.; Karlsson, M.K.; Downie, C.A.

    1995-01-01

    Drying augers and multicell DAF tanks are excellent machines in which to countercurrently wash soil and remove hazardous hydrocarbons, metals or radionuclides. An auger works well because it preferentially moves soil along one side of its trough. Thus, when enough high pressure and temperature water jets are placed along that path, contaminants can be melted, or dissolved and scoured from the soil. Contaminants and fines flow down the opposite side of the auger and out for extraction in a series of flotation tanks. Countercurrent washing of the silt results when soil settles in tanks through rising water and air bubbles then is pumped through cyclones placed above the next DAF tank of the series. LNAPLs, DNAPLs, or metallic contaminants made hydrophobic by chemicals in the system are removed at the overflow of the cyclones or by flotation in the tanks. The overflow from the cyclones and DAF tanks flows into the previous tank of the series. Examples of contaminants remediated include; arsenic, cadmium, lead and mercury, Naturally Occurring Radioactive Materials (NORM), uranium, solid oils, polyaromatic hydrocarbons in creosote and coal tars, and polychlorinated hydrocarbons

  3. Chemical and biological properties of toxic metals and use of chelating agents for the pharmacological treatment of metal poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Sinicropi, Maria Stefania; Caruso, Anna [University of Calabria, Department of Pharmaceutical Sciences, Rende (Italy); Amantea, Diana [University of Calabria, Department of Pharmacobiology, Rende (Italy); Saturnino, Carmela [University of Salerno, Department of Pharmaceutical Sciences, Fisciano (Italy)

    2010-07-15

    Exposure to toxic metals is a well-known problem in industrialized countries. Metals interfere with a number of physiological processes, including central nervous system (CNS), haematopoietic, hepatic and renal functions. In the evaluation of the toxicity of a particular metal it is crucial to consider many parameters: chemical forms (elemental, organic or inorganic), binding capability, presence of specific proteins that selectively bind metals, etc. Medical treatment of acute and chronic metal toxicity is provided by chelating agents, namely organic compounds capable of interacting with metal ions to form structures called chelates. The present review attempts to provide updated information about the mechanisms, the cellular targets and the effects of toxic metals. (orig.)

  4. Mycobacteria, Metals, and the Macrophage

    Science.gov (United States)

    Niederweis, Michael; Wolschendorf, Frank; Mitra, Avishek; Neyrolles, Olivier

    2015-01-01

    Summary Mycobacterium tuberculosis is a facultative intracellular pathogen that thrives inside host macrophages. A key trait of M. tuberculosis is to exploit and manipulate metal cation trafficking inside infected macrophages to ensure survival and replication inside the phagosome. Here we describe the recent fascinating discoveries that the mammalian immune system responds to infections with M. tuberculosis by overloading the phagosome with copper and zinc, two metals which are essential nutrients in small quantities but are toxic in excess. M. tuberculosis has developed multi-faceted resistance mechanisms to protect itself from metal toxicity including control of uptake, sequestration inside the cell, oxidation, and efflux. The host response to infections combines this metal poisoning strategy with nutritional immunity mechanisms that deprive M. tuberculosis from metals such as iron and manganese to prevent bacterial replication. Both immune mechanisms rely on the translocation of metal transporter proteins to the phagosomal membrane during the maturation process of the phagosome. This review summarizes these recent findings and discusses how metal-targeted approaches might complement existing TB chemotherapeutic regimens with novel anti-infective therapies. PMID:25703564

  5. Competitive sorption of heavy metals by water hyacinth roots.

    Science.gov (United States)

    Zheng, Jia-Chuan; Liu, Hou-Qi; Feng, Hui-Min; Li, Wen-Wei; Lam, Michael Hon-Wah; Lam, Paul Kwan-Sing; Yu, Han-Qing

    2016-12-01

    Heavy metal pollution is a global issue severely constraining aquaculture practices, not only deteriorating the aquatic environment but also threatening the aquaculture production. One promising solution is adopting aquaponics systems where a synergy can be established between aquaculture and aquatic plants for metal sorption, but the interactions of multiple metals in such aquatic plants are poorly understood. In this study, we investigated the absorption behaviors of Cu(II) and Cd(II) in water by water hyacinth roots in both single- and binary-metal systems. Cu(II) and Cd(II) were individually removed by water hyacinth roots at high efficiency, accompanied with release of protons and cations such as Ca 2+ and Mg 2+ . However, in a binary-metal arrangement, the Cd(II) sorption was significantly inhibited by Cu(II), and the higher sorption affinity of Cu(II) accounted for its competitive sorption advantage. Ionic exchange was identified as a predominant mechanism of the metal sorption by water hyacinth roots, and the amine and oxygen-containing groups are the main binding sites accounting for metal sorption via chelation or coordination. This study highlights the interactive impacts of different metals during their sorption by water hyacinth roots and elucidates the underlying mechanism of metal competitive sorption, which may provide useful implications for optimization of phytoremediation system and development of more sustainable aquaculture industry. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Analysis of the NASA White Sands Test Facility (WSTF) Test System for Friction-Ignition of Metallic Materials

    Science.gov (United States)

    Shoffstall, Michael S.; Wilson, D. Bruce; Stoltzfus, Joel M.

    2000-01-01

    Friction is a known ignition source for metals in oxygen-enriched atmospheres. The test system developed by the NASA White Sands Test Facility in response to ASTM G-94 has been used successfully to determine the relative ignition from friction of numerous metallic materials and metallic materials pairs. These results have been ranked in terms of a pressure-velocity product (PV) as measured under the prescribed test conditions. A high value of 4.1(exp 8) watts per square meter for Inconel MA 754 is used to imply resistance to friction ignition, whereas a low value of 1.04(exp 8) watts per square meter for stainless steel 304 is taken as indicating material susceptible to friction ignition. No attempt has been made to relate PV values to other material properties. This work reports the analysis of the WSTF friction-ignition test system for producing fundamental properties of metallic materials relating to ignition through friction. Three materials, aluminum, titanium, and nickel were tested in the WSTF frictional ignition instrument system under atmospheres of oxygen or nitrogen. Test conditions were modified to reach a steady state of operation, that is applied, the force was reduced and the rotational speed was reduced. Additional temperature measurements were made on the stator sample. The aluminum immediately galled on contact (reproducible) and the test was stopped. Titanium immediately ignited as a result of non-uniform contact of the stator and rotor. This was reproducible. A portion of the stator sampled burned, but the test continued. Temperature measurements on the stator were used to validate the mathematical model used for estimating the interface (stator/rotor) temperature. These interface temperature measurements and the associate thermal flux into the stator were used to distinguish material-phase transitions, chemical reaction, and mechanical work. The mechanical work was used to analyze surface asperities in the materials and to estimate a

  7. Research towards ultrasonic systems to assist in-vessel manipulations in liquid metal cooled reactors

    International Nuclear Information System (INIS)

    Dierckx, Marc; Van-Dyck, Dries

    2013-06-01

    We describe the state of the art of the research towards ultrasonic measurement methods for use in lead-bismuth cooled liquid metal reactors. Our current research activities are highly focused on specific tasks in the MYRRHA system, which is a fast spectrum research reactor cooled with the eutectic mixture of lead and bismuth (LBE) and is conceived as an accelerator driven system capable of operating in both sub-critical and critical mode. As liquid metal is opaque to light, normal visual feedback during fuel manipulations in the reactor vessel is not available and must therefore be replaced by a system that is not hindered by the opacity of the coolant. In this respect ultrasonic measurement techniques have been proposed and even developed in the past for operation in sodium cooled reactors. To our knowledge, no such systems have ever been deployed in lead based reactors and we are the first to have a research program in this direction as will be detailed in this paper. We give an overview of the acoustic properties of LBE and compare them with the properties of sodium and water to theoretically show the feasibility of ultrasonic systems operating in LBE. In the second part of the paper we discuss the results of the validation experiments in water and LBE. A typical scene is ultrasonically probed by a mechanical scanning system while the signals are processed to render a 3D visualization on a computer screen. It will become clear that mechanical scanning is capable of producing acceptable images but that it is a time consuming process that is not fit to solve the initial task to providing feedback during manipulations in the reactor vessel. That is why we propose to use several dedicated ultrasonic systems each adapted to a specific task and capable to provide real-time feedback of the ongoing manipulations, as is detailed in the third and final part of the paper. (authors)

  8. Removal of eutrophication factors and heavy metal from a closed cultivation system using the macroalgae, Gracilaria sp. (Rhodophyta)

    Science.gov (United States)

    Kang, Kyoung Ho; Sui, Zhenghong

    2010-11-01

    In this study, the ability of macroalgae Gracilaria sp. of removing eutrophication factors and toxic heavy metals Al, Cr, and Zn in a closed cultivation system is reported. The results show that the concentration of the three heavy metals decreased significantly during the experimental period in an algal biomass dependent manner. The biofiltration capacity of the alga for Al, Cr, and Zn is 10.1%-72.6%, 52.5%-83.4% and 36.5%-91.7%, respectively. Using more materials resulted in stronger heavy metal removal. Additionally, the concentration of chl- a, TN, TP and DIN of water samples from aquariums involving large, medium, and small algal biomass cultivation increased first and then decreased during the experiment. COD value of all three groups decreased with time and displayed algal biomass dependency: more algae resulting in a greater COD value than those of less biomass. Furthermore, changes in COD reflect an obvious organic particles deprivation process of algae. This is the first report on heavy metal removal effect by Gracilaria species. The results suggest that macroalgae can be used as a biofilter for the treatment of nutrient-enriched or heavy-metal polluted water, to which an appropriate time range should be carefully determined.

  9. Study of structure and surface morphology of two-layer contact Ti/Al metallization

    Directory of Open Access Journals (Sweden)

    Kirill D. Vanyukhin

    2016-06-01

    Full Text Available Ti/Al/Ni/Au metallization widely used in the technology of GaN base devices have a very important imperfection i.e. rough surface. There are different opinions about the causes of this imperfection: balling-up of molten aluminum or the appearance of intermetallic melt phases in the Au–Al system. To check the effect of the former cause, we have studied the formation of rough surface after annealing of Ti/Al metallization which is used as a basis of many metallization systems for GaN. The substrates were made from silicon wafers covered with Si3N4 films (0.15 μm. On these substrates we deposited the Ti(12 nm/Al(135 nm metallization system. After the deposition the substrates were annealed in nitrogen for 30 s at 850 °С. The as-annealed specimens were tested for metallization sheet resistivity, appearance and surface morphology. We have shown that during annealing of the Ti/Al metallization system, mutual diffusion of the metals and their active interaction with the formation of intermetallic phases occur. This makes the metallization system more resistant to subsequent annealing, oxidation and chemical etching. After annealing the surface of the Ti/Al metallization system becomes gently matted. However, large hemispherical convex areas (as in the Ti/Al/Ni/Au metallization system do not form. Thus, the hypothesis on the balling-up of molten aluminum on the surface of the Ti/Al metallization system has not been confirmed.

  10. Heavy metal uptake of Geosiphon pyriforme

    Energy Technology Data Exchange (ETDEWEB)

    Scheloske, Stefan E-mail: stefan.scheloske@mpi-hd.mpg.de; Maetz, Mischa; Schuessler, Arthur

    2001-07-01

    Geosiphon pyriforme represents the only known endosymbiosis between a fungus, belonging to the arbuscular mycorrhizal (AM) fungi, and cyanobacteria (blue-green algae). Therefore we use Geosiphon as a model system for the widespread AM symbiosis and try to answer some basic questions regarding heavy metal uptake or resistance of AM fungi. We present quantitative micro-PIXE measurements of a set of heavy metals (Cu, Cd, Tl, Pb) taken up by Geosiphon-cells. The uptake is studied as a function of the metal concentration in the nutrient solution and of the time Geosiphon spent in the heavy metal enriched medium. The measured heavy metal concentrations range from several ppm to some hundred ppm. Also the influence of the heavy metal uptake on the nutrition transfer of other elements will be discussed.

  11. Characterization for solidification and phase transformations of pure-titanium steel weld metal with time-resolved X-ray diffraction system

    International Nuclear Information System (INIS)

    Terasaki, Hidenori; Komizo, Yu-ichi; Nishino, Fumihiro; Ikeda, Masahiko

    2007-01-01

    Understanding and controlling solidification and phase transformation process of weld metal is essential for forming the microstructure with superior mechanical property. Recent evolution of analysis technique makes for solidification and phase transformation process to be in-situ analyzed, in direct and reciprocal lattice space. In the present work, unidirectional-solidification and phase transformation in the weld metal of commercial pure-titanium in Gas Tungsten Arc welding was in-situ observed by using Time-Resolved X-Ray Diffraction system with two-dimensional pixel detector. An undulator beam was used as a probe. Larger diffraction area could be detected in the time-resolution of 0.05 seconds, in unidirectional solidification and subsequent phase transformation process of pure-titanium weld metal. Furthermore, the microstructure formation during β-α phase transformation was in situ observed with High temperature Laser Scanning Confocal Microscopy. The crystal configurations in unidirectional solidification of weld metal and rapid change of phase ratio in reconstructive phase transformation were clearly analyzed. (author)

  12. Modeling of Heavy Metal Transformation in Soil Ecosystem

    Science.gov (United States)

    Kalinichenko, Kira; Nikovskaya, Galina N.

    2017-04-01

    The intensification of industrial activity leads to an increase in heavy metals pollution of soils. In our opinion, sludge from biological treatment of municipal waste water, stabilized under aerobic-anaerobic conditions (commonly known as biosolid), may be considered as concentrate of natural soil. In their chemical, physical and chemical and biological properties these systems are similar gel-like nanocomposites. These contain microorganisms, humic substances, clay, clusters of nanoparticles of heavy metal compounds, and so on involved into heteropolysaccharides matrix. It is known that microorganisms play an important role in the transformation of different nature substances in soil and its health maintenance. The regularities of transformation of heavy metal compounds in soil ecosystem were studied at the model of biosolid. At biosolid swelling its structure changing (gel-sol transition, weakening of coagulation contacts between metal containing nanoparticles, microbial cells and metabolites, loosening and even destroying of the nanocomposite structure) can occur [1, 2]. The promotion of the sludge heterotrophic microbial activities leads to solubilization of heavy metal compounds in the system. The microbiological process can be realized in alcaligeneous or acidogeneous regimes in dependence on the type of carbon source and followed by the synthesis of metabolites with the properties of flocculants and heavy metals extragents [3]. In this case the heavy metals solubilization (bioleaching) in the form of nanoparticles of hydroxycarbonate complexes or water soluble complexes with oxycarbonic acids is observed. Under the action of biosolid microorganisms the heavy metals-oxycarbonic acids complexes can be transformed (catabolised) into nano-sizing heavy metals- hydroxycarbonates complexes. These ecologically friendly complexes and microbial heteropolysaccharides are able to interact with soil colloids, stay in the top soil profile, and improve soil structure due

  13. Casimir Repulsion between Metallic Objects in Vacuum

    International Nuclear Information System (INIS)

    Levin, Michael; McCauley, Alexander P.; Rodriguez, Alejandro W.; Reid, M. T. Homer; Johnson, Steven G.

    2010-01-01

    We give an example of a geometry in which two metallic objects in vacuum experience a repulsive Casimir force. The geometry consists of an elongated metal particle centered above a metal plate with a hole. We prove that this geometry has a repulsive regime using a symmetry argument and confirm it with numerical calculations for both perfect and realistic metals. The system does not support stable levitation, as the particle is unstable to displacements away from the symmetry axis.

  14. Processes and procedures for a thin film multilevel hybrid circuit metallization system based on W--Au/SiO2/Al/SiO2

    International Nuclear Information System (INIS)

    Hampy, R.E.; Knauss, G.L.; Komarek, E.E.; Kramer, D.K.; Villanueva, J.

    1976-04-01

    The processes and procedures developed for the deposition and photodefinition of a W-Au/SiO 2 /Al/SiO 2 hybrid circuit metallization system for the SLL Micro Actuator are described. The metallization system affords a high degree of miniaturization and permits effective interconnection of a mixture of semiconductor devices and passive components with both gold and aluminum terminations without creating undesirable gold-aluminum interfaces. Sputtered tungsten-gold is the first level conductor except at crossovers where tungsten only is used and aluminum is the second level conductor. Silicon dioxide serves as an insulator between the tungsten and aluminum for crossovers. Vias in the insulating layer permit tungsten-aluminum interconnections where desired. A second layer of silicon dioxide is deposited over the metallization and opened for all gold and aluminum bonding pads. Substrates used were polished sapphire and fine grained alumina. The metallization is capable of withstanding processing temperatures up to 400 0 C for short times

  15. Corrosion of similar and dissimilar metal crevices in the engineered barrier system of a potential nuclear waste repository

    International Nuclear Information System (INIS)

    He, X.; Dunn, D.S.; Csontos, A.A.

    2007-01-01

    Crevice corrosion is considered possible if the corrosion potential (E corr ) exceeds the repassivation potential for crevice corrosion (E rcrev ). In this study, potentiodynamic polarization and potentiostatic hold were used to determine the E rcrev of similar and dissimilar metal crevices in the engineered barrier system of the potential Yucca Mountain repository in 0.5 M NaCl, 4 M NaCl, and 4 M MgCl 2 solutions at 95 deg. C. The results were compared with data previously obtained using crevices formed between Alloy 22 and polytetrafluoroethylene. It was observed that, except for Type 316L stainless steel, all other metal-to-metal crevices were less susceptible to crevice corrosion than the corresponding metal-to-polytetrafluoroethylene crevices. Measurements of galvanic coupling were used to evaluate the crevice corrosion propagation behavior in 5 M NaCl solution at 95 deg. C. The crevice specimens were coupled to either an Alloy 22 or a Titanium Grade 7 plate using metal or polytetrafluoroethylene crevice washers. Crevice corrosion of Type 316L stainless steel propagated without repassivation. For all the tests using a polytetrafluoroethylene crevice washer, crevice corrosion of Alloy 22 was initiated at open circuit potential by the addition of CuCl 2 as an oxidant, whereas no crevice corrosion of Alloy 22 was initiated for all the tests using Alloy 22 or Titanium Grade 7 metals as crevice washer. However, crevice corrosion propagation was found to be very limited under such test conditions

  16. Functional memory metals

    International Nuclear Information System (INIS)

    Dunne, D.P.

    2000-01-01

    The field of shape memory phenomena in metals and alloys has developed in a sporadic fashion from a scientific curiosity to a vigorously growing niche industry, over a period close to a full working lifetime. Memory metal research and development is replete with scientist and engineer 'true believers', who can finally feel content that their longstanding confidence in the potential of these unusual functional materials has not been misplaced. This paper reviews the current range of medical and non-medical systems and devices which are based on memory metals and attempts to predict trends in applications over the next decade. The market is dominated by Ni Ti alloys which have proved to exhibit the best and most reproducible properties for application in a wide range of medical and non-medical devices

  17. Extraordinary light transmission through opaque thin metal film with subwavelength holes blocked by metal disks.

    Science.gov (United States)

    Li, Wen-Di; Hu, Jonathan; Chou, Stephen Y

    2011-10-10

    We observed that when subwavelength-sized holes in an optically opaque metal film are completely covered by opaque metal disks larger than the holes, the light transmission through the holes is not reduced, but rather enhanced. Particularly we report (i) the observation of light transmission through the holes blocked by the metal disks up to 70% larger than the unblocked holes; (ii) the observation of tuning the light transmission by varying the coupling strength between the blocking disks and the hole array, or by changing the size of the disks and holes; (iii) the observation and simulation that the metal disk blocker can improve light coupling from free space to a subwavelength hole; and (iv) the simulation that shows the light transmission through subwavelength holes can be enhanced, even though the gap between the disk and the metal film is partially connected with a metal. We believe these finding should have broad and significant impacts and applications to optical systems in many fields.

  18. Heavy metal sorption by microalgae

    International Nuclear Information System (INIS)

    Sandau, E.; Sandau, P.; Pulz, O.

    1996-01-01

    Viable microalgae are known to be able to accumulate heavy metals (bioaccumulation). Against a background of the increasing environmental risks caused by heavy metals, the microalgae Chlorella vulgaris and Spirulina platensis and their potential for the biological removal of heavy metals from aqueous solutions were taken as an example for investigation. Small-scale cultivation tests (50 l) with Cd-resistant cells of Chlorella vulgaris have shown that approx. 40% of the added 10 mg Cd/l was removed from the solution within seven days. At this heavy metal concentration sensitive cells died. Non-viable microalgae are able to eliminate heavy metal ions in a short time by biosorption in uncomplicated systems, without any toxicity problems. Compared with original biomasses, the sorption capacity of microalgal by-products changes only insignificantly. Their low price makes them economical. (orig.)

  19. Tunneling Conductance in Ferromagnetic Metal/Normal Metal/Spin-Singlet -Wave Ferromagnetic Superconductor Junctions

    Directory of Open Access Journals (Sweden)

    Hamidreza Emamipour

    2013-01-01

    Full Text Available In the framework of scattering theory, we study the tunneling conductance in a system including two junctions, ferromagnetic metal/normal metal/ferromagnetic superconductor, where ferromagnetic superconductor is in spin-singlet -wave pairing state. The non-magnetic normal metal is placed in the intermediate layer with the thickness ( which varies from 1 nm to 10000 nm. The interesting result which we have found is the existence of oscillations in conductance curves. The period of oscillations is independent of FS and FN exchange field while it depends on . The obtained results can serve as a useful tool to determine the kind of pairing symmetry in ferromagnetic superconductors.

  20. Formation of bulk metallic glasses in the Fe-M-Y-B (M = transition metal) system

    Energy Technology Data Exchange (ETDEWEB)

    Huang, X.M. [International Center for New-Structured Materials (ICNSM) and Laboratory of New-Structured Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Chang, C.T. [Institute for Material Research, Tohoku University, Sendai 980-8577 (Japan); Chang, Z.Y.; Wang, X.D.; Cao, Q.P. [International Center for New-Structured Materials (ICNSM) and Laboratory of New-Structured Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Shen, B.L.; Inoue, A. [Institute for Material Research, Tohoku University, Sendai 980-8577 (Japan); Jiang, J.Z. [International Center for New-Structured Materials (ICNSM) and Laboratory of New-Structured Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)], E-mail: jiangjz@zju.edu.cn

    2008-07-28

    In this work, quaternary Fe{sub 72-x}M{sub x}Y{sub 6}B{sub 22} (M = Ni, Co and Mo) bulk metallic glasses (BMGs) have been developed. It is found that a fully amorphous Fe{sub 68}Mo{sub 4}Y{sub 6}B{sub 22} cylindrical rod with 6.5 mm in diameter can be prepared by copper mold injection. These alloys have a high glass transition temperature of about 900 K with high fracture strengths up to about 3 GPa although they are still brittle. Magnetic measurements reveal that they are ferromagnetic at ambient temperature with low coercive force of about 2 A/m, saturation magnetization of about 0.7 T and effective permeability of about 7000 at 100 kHz. The newly developed Fe-based quaternary alloys exhibit excellent combination properties: superior glass forming ability (GFA), high glass transition temperature, and soft magnetic properties, which could have potential applications in electronic industries. Furthermore, the effect of Mo addition on GFA in the Fe-Y-B BMG system has been discussed compared with those of Ni and Co additions.

  1. Controlled in-situ dissolution of an alkali metal

    Science.gov (United States)

    Jones, Jeffrey Donald; Dooley, Kirk John; Tolman, David Donald

    2012-09-11

    A method for the controllable dissolution of one or more alkali metals from a vessel containing a one or more alkali metals and/or one or more partially passivated alkali metals. The vessel preferably comprising a sodium, NaK or other alkali metal-cooled nuclear reactor that has been used. The alkali metal, preferably sodium, potassium or a combination thereof, in the vessel is exposed to a treatment liquid, preferably an acidic liquid, more preferably citric acid. Preferably, the treatment liquid is maintained in continuous motion relative to any surface of unreacted alkali metal with which the treatment liquid is in contact. The treatment liquid is preferably pumped into the vessel containing the one or more alkali metals and the resulting fluid is extracted and optionally further processed. Preferably, the resulting off-gases are processed by an off-gas treatment system and the resulting liquids are processed by a liquid disposal system. In one preferred embodiment, an inert gas is pumped into the vessel along with the treatment liquid.

  2. Liquid metal cooling concepts in solar power application

    International Nuclear Information System (INIS)

    Deegan, P.B.; Mangus, J.D.; Whitlow, G.A.

    1978-01-01

    The thermodynamic and thermophysical properties and proven technology of a liquid sodium heat transport system provide numerous advantages and benefits for application in a central receiver solar thermal power plant concept. The major advantages of utilizing liquid sodium are: attainment of high thermodynamic cycle efficiencies, reduced relative costs, and achievement of these goals by the mid-1980's through the utilization of proven liquid metal technology developed in the power industry, without the need for extensive development programs. The utilization of liquid sodium reduces the complexity of the design of these systems, thus providing confidence in system reliability. The implementation of the proven technology in liquid metal systems also provides assurance of reliability. In addition, the ease of transition from liquid metal breeder reactor systems to solar application provides immediate availability of this technology

  3. Evaluated phase diagrams of binary metal-tellurium systems of the D-block transition elements

    International Nuclear Information System (INIS)

    Chattopadhyay, G.; Bharadwaj, S.R.

    1989-01-01

    The binary phase diagrams of metal-tellurium systems for twenty seven d-block transition elements have been critically evaluated. Complete phase diagrams are presented for the elements, chromium, manganese, iron, cobalt, nickel, copper, molybdenum, palladium, silver, lanthanum, platinum and gold, whereas, for scandium, titanium, vanadium, yttrium, zirconium, niobium, technitium, ruthenium, rhodium, hafnium, tantalum, tungsten , rhenium, osmium and iridium, the phase diagrams are incomplete and tentative. (author). 20 refs., 27 tabs., 27 figs

  4. Biotechnology for the extractive metals industries

    Science.gov (United States)

    Brierley, James A.

    1990-01-01

    Biotechnology is an alternative process for the extraction of metals, the beneficiation of ores, and the recovery of metals from aqueous systems. Currently, microbial-based processes are used for leaching copper and uranium, enhancing the recovery of gold from refractory ores, and treating industrial wastewater to recover metal values. Future developments, emanating from fundamental and applied research and advances through genetic engineering, are expected to increase the use and efficiency of these biotechnological processes.

  5. Role of microgel formation in scavenging of chromophoric dissolved organic matter and heavy metals in a river-sea system.

    Science.gov (United States)

    Shiu, Ruei-Feng; Lee, Chon-Lin

    2017-04-15

    We use riverine and marine dissolved organic carbon (DOC) polymers to examine their aggregation behavior, and to evaluate the roles of microgel formation in scavenging of chromophoric dissolved organic matter (CDOM) and heavy metals in a river-sea system. Our results indicate that riverine and marine microgels did not exhibit very much difference in size and self-assembly curve; however, the assembly effectiveness ([microgel]/DOC) of marine samples was much higher than riverine. Instead of concentration of DOC, other factors such as types and sources of DOC polymers may control the microgel abundance in aquatic environments. After filtering water samples (microgels removed), the CDOM and selected metals (Cu, Ni, Mn) in the filtrate were quantified. CDOM and metals were concurrently removed to an extent via DOC polymer re-aggregation, which also suggested that the microgels had sequestering capability in CDOM and metals. This finding provides an alternative route for CDOM and heavy metals removal from the water column. As such the process of re-aggregation into microgels should then be considered besides traditional phase partitioning in the assessment of the ecological risk and fate of hazardous materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Assessment of Heavy Metal Pollution in Macrophytes, Water and Sediment of a Tropical Wetland System Using Hierarchical Cluster Analysis Technique

    OpenAIRE

    , N. Kumar J.I.; , M. Das; , R. Mukherji; , R.N. Kumar

    2011-01-01

    Heavy metal pollution in aquatic ecosystems is becoming a global phenomenon because these metals are indestructible and most of them have toxic effects on living organisms. Most of the fresh water bodies all over the world are getting contaminated thus declining their suitability. Therefore, monitoring and assessment of such freshwater systems has become an environmental concern. This study aims to elucidate the useful role of the cluster analysis to assess the relationship and interdependenc...

  7. Spin-exchange interaction between transition metals and metalloids in soft-ferromagnetic metallic glasses

    Science.gov (United States)

    Das, Santanu; Choudhary, Kamal; Chernatynskiy, Aleksandr; Choi Yim, Haein; Bandyopadhyay, Asis K.; Mukherjee, Sundeep

    2016-06-01

    High-performance magnetic materials have immense industrial and scientific importance in wide-ranging electronic, electromechanical, and medical device technologies. Metallic glasses with a fully amorphous structure are particularly suited for advanced soft-magnetic applications. However, fundamental scientific understanding is lacking for the spin-exchange interaction between metal and metalloid atoms, which typically constitute a metallic glass. Using an integrated experimental and molecular dynamics approach, we demonstrate the mechanism of electron interaction between transition metals and metalloids. Spin-exchange interactions were investigated for a Fe-Co metallic glass system of composition [(Co1-x Fe x )0.75B0.2Si0.05]96Cr4. The saturation magnetization increased with higher Fe concentration, but the trend significantly deviated from simple rule of mixtures. Ab initio molecular dynamics simulation was used to identify the ferromagnetic/anti-ferromagnetic interaction between the transition metals and metalloids. The overlapping band-structure and density of states represent ‘Stoner type’ magnetization for the amorphous alloys in contrast to ‘Heisenberg type’ in crystalline iron. The enhancement of magnetization by increasing iron was attributed to the interaction between Fe 3d and B 2p bands, which was further validated by valence-band study.

  8. Quality of Metal Deposited Flux Cored Wire With the System Fe-C-Si-Mn-Cr-Mo-Ni-V-Co

    Science.gov (United States)

    Gusev, Aleksander I.; Kozyrev, Nikolay A.; Osetkovskiy, Ivan V.; Kryukov, Roman E.; Kozyreva, Olga A.

    2017-10-01

    Studied the effect of the introduction of vanadium and cobalt into the charge powder fused wire system Fe-C-Si-Mn-Cr-Ni-Mo-V, used in cladding assemblies and equipment parts and mechanisms operating under abrasive and abrasive shock loads. the cored wires samples were manufactured in the laboratory conditions and using appropriate powder materials and as a carbonfluoride contained material were used the dust from gas purification of aluminum production, with the following components composition, %: Al2O3 = 21-46.23; F = 18-27; Na2O = 8-15; K2O = 0.4-6; CaO = 0.7-2.3; Si2O = 0.5-2.48; Fe2O3 = 2.1-3.27; C = 12.5-30.2; MnO = 0.07-0.9; MgO = 0.06-0.9; S = 0.09-0.19; P = 0.1-0.18. Surfacing was produced on the St3 metal plates in 6 layers under the AN-26C flux by welding truck ASAW-1250. Cutting and preparation of samples for research had been implemented. The chemical composition and the hydrogen content of the weld metal were determined by modern methods. The hardness and abrasion rate of weld metal had been measured. Conducted metallographic studies of weld metal: estimated microstructure, grain size, contamination of oxide non-metallic inclusions. Metallographic studies showed that the microstructure of the surfaced layer by cored wire system Fe-C-Si-Mn-Cr-Mo-Ni-V-Co is uniform, thin dendrite branches are observed. The microstructure consists of martensite, which is formed inside the borders of the former austenite grain retained austenite present in small amounts in the form of separate islands, and thin layers of δ-ferrite, which is located on the borders of the former austenite grains. Carried out an assessment the effect of the chemical composition of the deposited metal on the hardness and wear and hydrogen content. In consequence of multivariate correlation analysis, it was determined dependence to the hardness of the deposited layer and the wear resistance of the mass fraction of the elements included in the flux-cored wires of the system Fe

  9. Bioinspired surface functionalization of metallic biomaterials.

    Science.gov (United States)

    Su, Yingchao; Luo, Cheng; Zhang, Zhihui; Hermawan, Hendra; Zhu, Donghui; Huang, Jubin; Liang, Yunhong; Li, Guangyu; Ren, Luquan

    2018-01-01

    Metallic biomaterials are widely used for clinical applications because of their excellent mechanical properties and good durability. In order to provide essential biofunctionalities, surface functionalization is of particular interest and requirement in the development of high-performance metallic implants. Inspired by the functional surface of natural biological systems, many new designs and conceptions have recently emerged to create multifunctional surfaces with great potential for biomedical applications. This review firstly introduces the metallic biomaterials, important surface properties, and then elaborates some strategies on achieving the bioinspired surface functionalization for metallic biomaterials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Technique for detecting liquid metal leaks

    International Nuclear Information System (INIS)

    Bauerle, J.E.

    1979-01-01

    In a system employing flowing liquid metal as a heat transfer medium in contact with tubular members containing a working fluid, i.e., steam, liquid metal leaks through the wall of the tubular member are detected by dislodging the liquid metal compounds forming in the tubular member at the leak locations and subsequently transporting the dislodged compound in the form of an aerosol to a detector responsive to the liquid metal compound. In the application to a sodium cooled tubular member, the detector would consist of a sodium responsive device, such as a sodium ion detector

  11. Nonlinear Color–Metallicity Relations of Globular Clusters. VII. Nonlinear Absorption-line Index versus Metallicity Relations and Bimodal Index Distributions of NGC 5128 Globular Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sooyoung; Yoon, Suk-Jin, E-mail: sjyoon0691@yonsei.ac.kr [Department of Astronomy and Center for Galaxy Evolution Research, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2017-07-01

    Spectroscopy on the globular cluster (GC) system of NGC 5128 revealed bimodality in absorption-line index distributions of its old GCs. GC division is a widely observed and studied phenomenon whose interpretation has depicted host galaxy formation and evolution such that it harbors two distinct metallicity groups. Such a conventional view of GC bimodality has mainly been based on photometry. The recent GC photometric data, however, presented an alternative perspective in which the nonlinear metallicity-to-color transformation is responsible for color bimodality of GC systems. Here we apply the same line of analysis to the spectral indices and examine the absorption-line index versus metallicity relations for the NGC 5128 GC system. NGC 5128 GCs display nonlinearity in the metallicity-index planes, most prominently for the Balmer lines and by a non-negligible degree for the metallicity-sensitive magnesium line. We demonstrate that the observed spectroscopic division of NGC 5128 GCs can be caused by the nonlinear nature of the metallicity-to-index conversions and thus one does not need to resort to two separate GC subgroups. Our analysis incorporating this nonlinearity provides a new perspective on the structure of NGC 5128's GC system, and a further piece to the global picture of the formation of GC systems and their host galaxies.

  12. Localized versus collective behaviour of d-electrons in transition metal oxide systems of perovskite systems

    Energy Technology Data Exchange (ETDEWEB)

    Rao, C N.R. [Indian Inst. of Tech., Kanpur

    1974-12-01

    The behavior of d-electrons in perovskites of the type LnZO/sub 3/ (Z = trivalent transition metal ion and Ln = rare earth or yttrium) depends on the spin configuration of the transition metal ion. LaTiO/sub 3/ and LaNiO/sub 3/ with low-spin transition metal ions (S = 1/2) are metallic while LaCrO/sub 3/, LnMnO/sub 3/ and LnFeO/sub 3/ with high-spin ions are poor semiconductors exhibiting localized behavior of d-electrons. In rare earth cobaltites, the cobalt ions are present mainly in the diamagnetic low-spin Co /sup III/ state at low temperatures. The Co/sup III/ ions transform to high-spin Co/sup 3 +/ ions with increase in temperature. At higher temperatures, there is electron-transfer from Co/sup 3 +/ to Co/sup III/ions producing intermetallic states. Spin-state transitions are seen in these cobaltites in the range 150-870/sup 0/K. At high temperatures, the cobaltites show evidence for localized-itinerant electron transitions. In La/sub 1-x/ Sr/sub x/CoO/sub 3/ there is onset of ferromagnetism at x > 0.125, at which point there is a structural dicontinuity and electrons become itinerant. The composition with x = 0.5 is metallic and T/sub c/ = 230/sup 0/K. The ferromagnetic component in La/sub 1-x/Sr/sub x/ CoO/sub 3/ increases with x in the range 0.125-0.50. Catalytic properties of rare earth cobaltites appear to be related to the spin state equilibria. (auth)

  13. Evaluating the capabilities of aerosol-to-liquid particle extraction system (ALPXS)/ICP-MS for monitoring trace metals in indoor air.

    Science.gov (United States)

    Jayawardene, Innocent; Rasmussen, Pat E; Chenier, Marc; Gardner, H David

    2014-09-01

    This study investigates the application of the Aerosol-to-Liquid Particle Extraction System (ALPXS), which uses wet electrostatic precipitation to collect airborne particles, for multi-element indoor stationary monitoring. Optimum conditions are determined for capturing airborne particles for metal determination by inductively coupled plasma-mass spectrometry (ICP-MS), for measuring field blanks, and for calculating limits of detection (LOD) and quantification (LOQ). Due to the relatively high flow rate (300 L min(-1)), a sampling duration of 1 hr to 2 hr was adequate to capture airborne particle-bound metals under the investigated experimental conditions. The performance of the ALPXS during a building renovation demonstrated signal-to-noise ratios appropriate for sampling airborne particles in environments with elevated metal concentrations, such as workplace settings. The ALPXS shows promise as a research tool for providing useful information on short-term variations (transient signals) and for trapping particles into aqueous solutions where needed for subsequent characterization. As the ALPXS does not provide size-specific samples, and its efficiency at different flow rates has yet to be quantified, the ALPXS would not replace standard filter-based protocols accepted for regulatory applications (e.g., exposure measurements), but rather would provide additional information if used in conjunction with filter based methods. Implications: This study investigates the capability of the Aerosol-to-Liquid Particle Extraction System (ALPXS) for stationary sampling of airborne metals in indoor workplace environments, with subsequent analysis by ICP-MS. The high flow rate (300 L/min) permits a short sampling duration (< 2 hr). Results indicated that the ALPXS was capable of monitoring short-term changes in metal emissions during a renovation activity. This portable instrument may prove to be advantageous in occupational settings as a qualitative indicator of elevated

  14. Archive-cup insert for liquid-metal sampling

    International Nuclear Information System (INIS)

    Nelson, P.A.; Kolba, V.M.; Filewicz, E.C.; Holmes, J.T.

    1975-01-01

    An insert for collecting liquid-metal samples within a vertical casing including an elongated housing with an upper and a lower overflow seal of annular shape is described. The lower seal includes a centrally located pedestal on which a sample cup is disposed. Liquid metal enters the annulus of the upper seal and overflows into the cup which fills and overflows into the lower seal. Liquid-metal overflow from the lower seal is discharged from the insert. On cooling, the liquid metal trapped within the seals solidifies to hermetically isolate the metal sample within the cup. The device is particularly applicable for use with sampling systems on liquid metal-cooled reactors. (U.S.)

  15. A city scale study on the effects of intensive groundwater heat pump systems on heavy metal contents in groundwater.

    Science.gov (United States)

    García-Gil, Alejandro; Epting, Jannis; Garrido, Eduardo; Vázquez-Suñé, Enric; Lázaro, Jesús Mateo; Sánchez Navarro, José Ángel; Huggenberger, P; Calvo, Miguel Ángel Marazuela

    2016-12-01

    As a result of the increasing use of shallow geothermal resources, hydraulic, thermal and chemical impacts affecting groundwater quality can be observed with ever increasing frequency (Possemiers et al., 2014). To overcome the uncertainty associated with chemical impacts, a city scale study on the effects of intensive geothermal resource use by groundwater heat pump systems on groundwater quality, with special emphasis on heavy metal contents was performed. Statistical analysis of geochemical data obtained from several field campaigns has allowed studying the spatiotemporal relationship between temperature anomalies in the aquifer and trace element composition of groundwater. The relationship between temperature and the concentrations of trace elements resulted in weak correlations, indicating that temperature changes are not the driving factor in enhancing heavy metal contaminations. Regression models established for these correlations showed a very low reactivity or response of heavy metal contents to temperature changes. The change rates of heavy metal contents with respect to temperature changes obtained indicate a low risk of exceeding quality threshold values by means of the exploitation regimes used, neither producing nor enhancing contamination significantly. However, modification of pH, redox potential, electrical conductivity, dissolved oxygen and alkalinity correlated with the concentrations of heavy metals. In this case, the change rates of heavy metal contents are higher, with a greater risk of exceeding threshold values. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Liquid metal thermal-hydraulics

    International Nuclear Information System (INIS)

    Kottowski-Duemenil, H.M.

    1994-01-01

    This textbook is a report of the 26 years activity of the Liquid Metal Boiling Working Group (LMBWG). It summarizes the state of the art of liquid metal thermo-hydraulics achieved through the collaboration of scientists concerned with the development of the Fast Breeder Reactor. The first chapter entitled ''Liquid Metal Boiling Behaviour'', presents the background and boiling mechanisms. This section gives the reader a brief but thorough survey on the superheat phenomena in liquid metals. The second chapter of the text, ''A Review of Single and Two-Phase Flow Pressure Drop Studies and Application to Flow Stability Analysis of Boiling Liquid Metal Systems'' summarizes the difficulty of pressure drop simulation of boiling sodium in core bundles. The third chapter ''Liquid Metal Dry-Out Data for Flow in Tubes and Bundles'' describes the conditions of critical heat flux which limits the coolability of the reactor core. The fourth chapter dealing with the LMFBR specific topic of ''Natural Convection Cooling of Liquid Metal Systems''. This chapter gives a review of both plant experiments and out-of-pile experiments and shows the advances in the development of computing power over the past decade of mathematical modelling ''Subassembly Blockages Suties'' are discussed in chapter five. Chapter six is entitled ''A Review of the Methods and Codes Available for the Calculation on Thermal-Hydraulics in Rod-Cluster and other Geometries, Steady state and Transient Boiling Flow Regimes, and the Validation achieves''. Codes available for the calculation of thermal-hydraulics in rod-clusters and other geometries are reviewed. Chapter seven, ''Comparative Studies of Thermohydraulic Computer Code Simulations of Sodium Boiling under Loss of Flow Conditions'', represents one of the key activities of the LMBWG. Several benchmark exercises were performed with the aim of transient sodium boiling simulation in single channels and bundle blockages under steady state conditions and loss of

  17. Viscosity of SiO2-"FeO"-Al2O3 System in Equilibrium with Metallic Fe

    Science.gov (United States)

    Chen, Mao; Raghunath, Sreekanth; Zhao, Baojun

    2013-08-01

    The present study delivered the measurements of viscosities in SiO2-"FeO"-Al2O3 system in equilibrium with metallic Fe. The rotational spindle technique was used in the measurements at the temperature range of 1473 K to 1773 K (1200 °C to 1500 °C). Molybdenum crucibles and spindles were employed in all measurements. The Fe saturation condition was maintained by an iron plate placed at the bottom of the crucible. The equilibrium compositions of the slags were measured by EPMA after the viscosity measurements. The effect of up to 20 mol. pct Al2O3 on the viscosity of the SiO2-"FeO" slag was investigated. The "charge compensation effect" of the Al2O3 and FeO association has been discussed. The modified quasi-chemical viscosity model has been optimized in the SiO2-"FeO"-Al2O3 system in equilibrium with metallic Fe to describe the viscosity measurements of the present study.

  18. Comparison of Shear Bond Strengths of three resin systems for a Base Metal Alloy bonded to

    Directory of Open Access Journals (Sweden)

    Jlali H

    1999-12-01

    Full Text Available Resin-bonded fixed partial dentures (F.P.D can be used for conservative treatment of partially edentulous"npatients. There are numerous studies regarding the strength of resin composite bond to base meta! alloys. Shear bond"nstrength of three resin systems were invistigated. In this study these systems consisted of: Panavia Ex, Mirage FLC and"nMarathon V. Thirty base metal specimens were prepared from rexillium III alloy and divided into three groups. Then each"ngroup was bonded to enamel of human extracted molar teeth with these systems. All of specimens were stored in water at"n37ac for 48 hours. A shear force was applied to each specimen by the instron universal testing machine. A statistical"nevaluation of the data using one-way analysis of variance showed that there was highly significant difference (P<0.01"nbetween the bond strengths of these three groups."nThe base metal specimens bonded with panavia Ex luting agent, exhibited the highest mean bond strength. Shear bond"nstrength of the specimens bonded to enamel with Mirage F1C showed lower bond strenght than panavia EX. However, the"nlowest bond strength was obtained by the specimens bonded with Marathon V.

  19. Evaluation of metals and radionuclides in water treatment system for drinking in Pernambuco state, Brazil

    International Nuclear Information System (INIS)

    Albuquerque, Adriana Muniz de Almeida

    2017-01-01

    The metals and radionuclides are naturally incorporated into natural waters, and may be present at levels that condition the health of the population. In view of this, health agencies regulate standards which determine maximum concentration values for these elements in water intended for human consumption. However, the water sources do not have the required quality and the application of treatment technologies is necessary. These technologies remove the impurities initially incorporated into the waters of the fountains from the application of physical and chemical processes. The impurities are retained and concentrated in the treatment systems giving rise to a residue which may contain appreciable concentrations of metals and radionuclides, and this residue is included among the United States Environmental Protection Agency (USEPA). In the present study, the investigation of raw, treated and wastewater samples from 19 Water Treatment Stations located in the state of Pernambuco, in relation to the behavior of Al, Cd, Cu, Cr, Fe, Mn, Ni, Pb and Zn and radionuclides 226 Ra and 228 Ra, alpha and beta total and gamma emitters in the treatment systems, from the analysis of the concentrations of these in the waters and residues, evaluating the suitability of the waters in accordance with established in the norms in force, as well as the associated with the disposal of wastes that are commonly released into the environment. The results obtained for the metals indicated that the treatment systems must have their processes optimized to ensure the adequacy of the water supplied to the population to the potability parameters and for the residues levels that could generate environmental risk were observed. For the radionuclides the levels found in the waters were low, indicating a low contribution of these to the sources undergoing treatment, and in the residues the levels were low, but within the range described in the literature, corroborating its classification as a TENORM

  20. Application of neutron activation analysis to the development of a monitoring system for trace metals in coastal waters

    International Nuclear Information System (INIS)

    Karbe, L.; Schnier, C.

    1976-03-01

    In view of the development of monitoring systems for trace metals in coastal waters, a research program has been started for a better understanding of interrelationships between input of trace metals, water chemistry, suspended matter, sediment and organisms. For multielement determinations neutron activation analysis has been chosen. Since environmental studies require the analysis of a large number of samples, the efficiency of the method is improved by automation of the acquisition and analysis of the γ-spectra from the Ge(Li) detectors. An automatic sample changer with counting device is described. First applications of the method in environmental research are presented. (orig.) [de