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Sample records for prevent copper diffusion

  1. Self-diffusion on copper surfaces

    DEFF Research Database (Denmark)

    Hansen, L.; Stoltze, Per; Jacobsen, Karsten Wedel

    1991-01-01

    The diffusion paths and activation energies of a Cu adatom on Cu(100), Cu(111), and Cu(110) are studied using the effective-medium theory to calculate the energetics. For the (100) and (110) faces, diffusion via an exchange mechanism is found to be important. The transition state for these paths ...

  2. Grain boundary and triple junction diffusion in nanocrystalline copper

    Energy Technology Data Exchange (ETDEWEB)

    Wegner, M., E-mail: m.wegner@uni-muenster.de; Leuthold, J.; Peterlechner, M.; Divinski, S. V., E-mail: divin@uni-muenster.de [Institut für Materialphysik, Universität Münster, Wilhelm-Klemm-Straße 10, D-48149, Münster (Germany); Song, X., E-mail: xysong@bjut.edu.cn [College of Materials Science and Engineering, Beijing University of Technology, 100124 Beijing (China); Wilde, G. [Institut für Materialphysik, Universität Münster, Wilhelm-Klemm-Straße 10, D-48149, Münster (Germany); Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, 200444 Shanghai (China)

    2014-09-07

    Grain boundary and triple junction diffusion in nanocrystalline Cu samples with grain sizes, 〈d〉, of ∼35 and ∼44 nm produced by spark plasma sintering were investigated by the radiotracer method using the {sup 63}Ni isotope. The measured diffusivities, D{sub eff}, are comparable with those determined previously for Ni grain boundary diffusion in well-annealed, high purity, coarse grained, polycrystalline copper, substantiating the absence of a grain size effect on the kinetic properties of grain boundaries in a nanocrystalline material at grain sizes d ≥ 35 nm. Simultaneously, the analysis predicts that if triple junction diffusion of Ni in Cu is enhanced with respect to the corresponding grain boundary diffusion rate, it is still less than 500⋅D{sub gb} within the temperature interval from 420 K to 470 K.

  3. Ultrasonic evaluation of beryllium-copper diffusion bonds

    Energy Technology Data Exchange (ETDEWEB)

    Jamieson, E.E.

    2000-06-08

    A study was performed to compare the effectiveness of several advanced ultrasonic techniques when used to determine the strength of diffusion bonded beryllium-copper, which heretofore have each been applied to only a few material systems. The use of integrated backscatter calculations, frequency domain reflection coefficients, and time-of-flight variance was compared in their ability to characterize the bond strength in a series of beryllium-copper diffusion bond samples having a wide variation in bond quality. Correlation of integrated backscatter calculations and time-of-flight variance with bond strength was good. Some correlation of the slope of the frequency based reflection coefficient was shown for medium and high strength bonds, while its Y-intercept showed moderate correlation for all bond strengths.

  4. Copper diffusion in TaN-based thin layers

    Energy Technology Data Exchange (ETDEWEB)

    Nazon, J. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France); Fraisse, B. [Laboratoire Structure, Proprietes et Modelisation des Solides (UMR 8580), Ecole Centrale de Paris, Grande Voie des Vignes, 92295 Chatenay-Malabry Cedex (France); Sarradin, J. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France); Fries, S.G. [SGF Scientific Consultancy, Arndt str.9, D-52064 Aachen (Germany); Tedenac, J.C. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France); Frety, N. [Universite Montpellier II, Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, cc 1504, 34095 Montpellier Cedex 5 (France)], E-mail: Nicole.Frety@univ-montp2.fr

    2008-07-15

    The diffusion of Cu through TaN-based thin layers into a Si substrate has been studied. The barrier efficiency of TaN/Ta/TaN multilayers of 150 nm in thickness has been investigated and is compared with that of TaN single layers. Thermal stabilities of these TaN-based thin layers against Cu diffusion were determined from in situ X-ray diffraction experiments, conducted in the temperature range of 773-973 K. The TaN/Ta/TaN barrier appeared to be more efficient in preventing Cu diffusion than the TaN single layer.

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

    Directory of Open Access Journals (Sweden)

    J. W. Elmer

    2001-05-01

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

  6. Prevention of pin tract infection with titanium-copper alloys.

    Science.gov (United States)

    Shirai, Toshiharu; Tsuchiya, Hiroyuki; Shimizu, Tohru; Ohtani, Kaori; Zen, Yo; Tomita, Katsuro

    2009-10-01

    The most frequent complication in external fixation is pin tract infection. To reduce the incidence of implant-associated infection, many published reports have looked at preventing bacterial adhesion by treating the pin surface. This study aimed to evaluate the antibacterial activity of a Titanium-Copper (Ti-Cu) alloy on implant infection, and to determine the potential use of the Ti-Cu alloy as a biomaterial. Two forms of Ti-Cu alloys were synthesized: one with 1% Cu and the other with 5% Cu. For analyzing infectious behavior, the implants were exposed to Staphylococcus aureus and Escherichia coli. The reaction of pathogens to the Ti-Cu alloys was compared with their reaction to stainless steel and pure titanium as controls. Both Ti-Cu alloys evidently inhibited colonization by both bacteria. Conversely, cytocompatibility studies were performed using fibroblasts and colony formation on the metals was assessed by counting the number of colonies. Ti-1% Cu alloy showed no difference in the number of colonies compared with the control. External fixator pins made of Ti-Cu alloys were evaluated in a rabbit model. The tissue-implant interactions were analyzed for the presence of infection, inflammatory changes and osteoid-formation. Ti-1% Cu alloy significantly inhibited inflammation and infection, and had excellent osteoid-formation. Copper blood levels were measured before surgery and at 14 days postoperatively. Preoperative and postoperative blood copper values were not statistically different. Overall, it was concluded that Ti-Cu alloys have antimicrobial activity and substantially reduce the incidence of pin tract infection. Ti-1% Cu alloy shows particular promise as a biomaterial. (c) 2009 Wiley Periodicals, Inc.

  7. How thin barrier metal can be used to prevent Co diffusion in the modern integrated circuits?

    International Nuclear Information System (INIS)

    Dixit, Hemant; Konar, Aniruddha; Pandey, Rajan; Ethirajan, Tamilmani

    2017-01-01

    In modern integrated circuits (ICs), billions of transistors are connected to each other via thin metal layers (e.g. copper, cobalt, etc) known as interconnects. At elevated process temperatures, inter-diffusion of atomic species can occur among these metal layers, causing sub-optimal performance of interconnects, which may lead to the failure of an IC. Thus, typically a thin barrier metal layer is used to prevent the inter-diffusion of atomic species within interconnects. For ICs with sub-10 nm transistors (10 nm technology node), the design rule (thickness scaling) demands the thinnest possible barrier layer. Therefore, here we investigate the critical thickness of a titanium–nitride (TiN) barrier that can prevent the cobalt diffusion using multi-scale modeling and simulations. First, we compute the Co diffusion barrier in crystalline and amorphous TiN with the nudged elastic band method within first-principles density functional theory simulations. Later, using the calculated activation energy barriers, we quantify the Co diffusion length in the TiN metal layer with the help of kinetic Monte Carlo simulations. Such a multi-scale modelling approach yields an exact critical thickness of the metal layer sufficient to prevent the Co diffusion in IC interconnects. We obtain a diffusion length of a maximum of 2 nm for a typical process of thermal annealing at 400 °C for 30 min. Our study thus provides useful physical insights for the Co diffusion in the TiN layer and further quantifies the critical thickness (∼2 nm) to which the metal barrier layer can be thinned down for sub-10 nm ICs. (paper)

  8. Diffusion in copper sulphides. An experimental study of chalcocite, chalcopyrite and bornite

    Energy Technology Data Exchange (ETDEWEB)

    Berger, R.; Bucur, R.V. [Uppsala Univ. (Sweden). Inst. of Chemistry

    1996-01-01

    Diffusion measurements on three copper-containing sulphides have been performed by an electrochemical potentiometric method. Chalcocite (Cu{sub 2}S), Chalcopyrite (CuFeS{sub 2}) and Bornite (Cu{sub 5}FeS{sub 4}) were synthesized and fully characterized by X-ray diffraction. The diffusivities were measured on compacted powders yielding both the chemical and the component diffusion coefficients in the temperature range 5-50 C. The chemical diffusion coefficients found were: for Chalcocite 38.7*exp (-5600/T), for Chalcopyrite 15.4*exp(-6000/T) and for Bornite 14.4*exp(-4900/T). The diffusion coefficient for Chalcocite is in good agreement with values found previously, and a reasonable agreement is also found for Chalcopyrite and Bornite when our data are compared with values acquired at much higher temperatures with a different technique. The activation energies (here on a Kelvin scale) are remarkably similar for the three sulfides, considering that their relative errors are of a 10% magnitude, which indicates that the bonding strengths and the diffusion mechanisms are similar. The chemical diffusion coefficients which enter the empirical Fick`s diffusion laws that describe concentration changes, are of the order of exp(-8) to exp (-7) cm{sup 2}/s at room temperature. Such values bring the ion mobilities near values found for solid state `fast ion conductors`, used as electrolytes at elevated temperatures. 17 refs, 8 figs, 5 tabs.

  9. Diffusion in copper sulphides. An experimental study of chalcocite, chalcopyrite and bornite

    International Nuclear Information System (INIS)

    Berger, R.; Bucur, R.V.

    1996-01-01

    Diffusion measurements on three copper-containing sulphides have been performed by an electrochemical potentiometric method. Chalcocite (Cu 2 S), Chalcopyrite (CuFeS 2 ) and Bornite (Cu 5 FeS 4 ) were synthesized and fully characterized by X-ray diffraction. The diffusivities were measured on compacted powders yielding both the chemical and the component diffusion coefficients in the temperature range 5-50 C. The chemical diffusion coefficients found were: for Chalcocite 38.7*exp (-5600/T), for Chalcopyrite 15.4*exp(-6000/T) and for Bornite 14.4*exp(-4900/T). The diffusion coefficient for Chalcocite is in good agreement with values found previously, and a reasonable agreement is also found for Chalcopyrite and Bornite when our data are compared with values acquired at much higher temperatures with a different technique. The activation energies (here on a Kelvin scale) are remarkably similar for the three sulfides, considering that their relative errors are of a 10% magnitude, which indicates that the bonding strengths and the diffusion mechanisms are similar. The chemical diffusion coefficients which enter the empirical Fick's diffusion laws that describe concentration changes, are of the order of exp(-8) to exp (-7) cm 2 /s at room temperature. Such values bring the ion mobilities near values found for solid state 'fast ion conductors', used as electrolytes at elevated temperatures. 17 refs, 8 figs, 5 tabs

  10. The analysis of beryllium-copper diffusion joint after HHF test

    International Nuclear Information System (INIS)

    Guiniatouline, R.N.; Mazul, I.V.; Rubkin, S.Y.

    1995-01-01

    The development of beryllium-copper joints which can withstand to relevant ITER divertor conditions is one of the important tasks at present time. One of the main problem for beryllium-copperjoints, is the inter-metallic layers, the strength and life time of joints significantly depends from the width and contents of the intermetallic layers. The objective of this work is to study the diffusion joint of TGP-56 beryllium to OFHC copper after thermal response and thermocyclic tests with beryllium-copper mockup. The BEY test were performed at e-beam facility (EBTS, SNLA). The following methods were used for analyses: the roentgenographic analysis; X-ray spectrum analysis; the fracture graphic analysis. During the investigation the followed studies were done: the analysis of diffusion boundary Be-Cu, which was obtained at the crossection of one of the tiles, the analysis of the debonded surfaces of a few beryllium tiles and corresponding copper parts; the analysis of upper surface of one of the tiles after HHF tests. The results of this work have showed that: the joint roentgenographic and elements analyses indicated the following phases in the diffusion zone: Cu 2 Be (∼170 μm), CuBe (∼30μm), CuBe 2 (∼1 μm) and solid solution of copper in beryllium. The phases Cu 2 Be, CuBe and solid solution of copper in beryllium were indicated using quantitative microanalysis and phases CuBe, CuBe 2 , Cu, Be - by roentgenographic analysis; the source of fracture (initial crack) is located in the central part of the tiles, the crack caused by the influence of residual stresses during cooling of a mock-up after fabrication and developed under the conditions of slow elastic-plastic growing during the process of thermal fatigue testing. The analysis gives the important data about joint's quality and also may be used for any type of joints and its comparison for ITER applications

  11. Development of a new passive sampler based on diffusive milligel beads for copper analysis in water

    Energy Technology Data Exchange (ETDEWEB)

    Perez, M.; Reynaud, S.; Lespes, G.; Potin-Gautier, M. [Université de Pau et des Pays de l’Adour/CNRS UMR IPREM 5254, Hélioparc, 2 av. du Président Angot, 64053 Pau (France); Mignard, E. [CNRS-Solvay-Université Bordeaux, UMR5258, Laboratoire du Futur, 178 Avenue du Dr. A. Schweitzer, 33608 Pessac Cedex (France); Chéry, P. [Bordeaux Science Agro, 1 cours du Général De Gaulle, Gradignan, 33175 (France); Schaumlöffel, D. [Université de Pau et des Pays de l’Adour/CNRS UMR IPREM 5254, Hélioparc, 2 av. du Président Angot, 64053 Pau (France); Grassl, B., E-mail: bruno.grassl@univ-pau.fr [Université de Pau et des Pays de l’Adour/CNRS UMR IPREM 5254, Hélioparc, 2 av. du Président Angot, 64053 Pau (France)

    2015-08-26

    A new passive sampler was designed and characterized for the determination of free copper ion (Cu{sup 2+}) concentration in aqueous solution. Each sampling device was composed of a set of about 30 diffusive milligel (DMG) beads. Milligel beads with incorporated cation exchange resin (Chelex) particles were synthetized using an adapted droplet-based millifluidic process. Beads were assumed to be prolate spheroids, with a diameter of 1.6 mm and an anisotropic factor of 1.4. The milligel was controlled in chemical composition of hydrogel (monomer, cross-linker, initiator and Chelex concentration) and characterized in pore size. Two types of sampling devices were developed containing 7.5% and 15% of Chelex, respectively, and 6 nm pore size. The kinetic curves obtained demonstrated the accumulation of copper in the DMG according to the process described in the literature as absorption (and/or adsorption) and release following the Fick's first law of diffusion. For their use in water monitoring, the typical physico-chemical characteristics of the samplers, i.e. the mass-transfer coefficient (k{sub 0}) and the sampler-water partition coefficient (K{sub sw}), were determined based on a static exposure design. In order to determine the copper concentration in the samplers after their exposure, a method using DMG bead digestion combined to Inductively Coupled Plasma – Atomic Emission Spectrometry (ICP-AES) analysis was developed and optimized. The DMG devices proved to be capable to absorb free copper ions from an aqueous solution, which could be accurately quantified with a mean recovery of 99% and a repeatability of 7% (mean relative uncertainty). - Highlights: • Controlled geometry of new passive sampler with ellipsoidal shape. • Original manufacturing process based on droplet-based millifluidic device. • Pore size characterization of the sampler. • Mass-transfer and sampler-water partitioning coefficients by static exposure experiments.

  12. On copper diffusion in silicon measured by glow discharge mass spectrometry.

    Science.gov (United States)

    Modanese, Chiara; Gaspar, Guilherme; Arnberg, Lars; Di Sabatino, Marisa

    2014-11-01

    Copper contamination occurs frequently in silicon for photovoltaic applications due to its very fast diffusion coupled with a low solid solubility, especially at room temperature. The combination of these properties exerts a challenge on the direct analysis of Cu bulk concentration in Si by sputtering techniques like glow discharge mass spectrometry (GDMS). This work aims at addressing the challenges in quantitative analysis of fast diffusing elements in Si matrix by GDMS. N-type, monocrystalline (Czochralski) silicon samples were intentionally contaminated with Cu after solidification and consequently annealed at 900 °C to ensure a homogeneous distribution of Cu in the bulk. The samples were quenched after annealing to control the extent of the diffusion to the surface prior to the GDMS analyses, which were carried out at different time intervals from within few minutes after cooling onward. The Cu profiles were measured by high-resolution GDMS operating in a continuous direct current mode, where the integration step length was set to ∼0.5 μm over a total sputtered depth of 8-30 μm. The temperature of the samples during the GDMS analyses was also measured in order to evaluate the diffusion. The Cu contamination of n-type Si samples was observed to be highly material dependent. The practical impact of Cu out-diffusion on the calculation of the relative sensitivity factor (RSF) of Cu in Si is discussed.

  13. Application of copper to prevent and control infection. Where are we now?

    LENUS (Irish Health Repository)

    O'Gorman, J

    2012-08-01

    The antimicrobial effect of copper has long been recognized and has a potential application in the healthcare setting as a mechanism to reduce environmental contamination and thus prevent healthcare-associated infection (HCAI).

  14. A Nanolayer Copper Coating for Prevention Nosocomial Multi-Drug Resistant Infections

    Science.gov (United States)

    2016-10-01

    AWARD NUMBER: W81XWH-15-2-0066 TITLE: A Nanolayer Copper Coating for Prevention Nosocomial Multi- drug Resistant Infections PRINCIPAL...SUBTITLE A Nanolayer Copper Coating for Prevention Nosocomial Multi- drug Resistant Infections 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-15-2-0066 5c...for in vitro antimicrobial efficacy and mammalian cell cytotoxicity potential using standardized assays that are approved by the Food and Drug

  15. CROSS DIFFUSION AND NONLINEAR DIFFUSION PREVENTING BLOW UP IN THE KELLER–SEGEL MODEL

    KAUST Repository

    CARRILLO, JOSÉ ANTONIO

    2012-12-01

    A parabolic-parabolic (Patlak-)Keller-Segel model in up to three space dimensions with nonlinear cell diffusion and an additional nonlinear cross-diffusion term is analyzed. The main feature of this model is that there exists a new entropy functional, yielding gradient estimates for the cell density and chemical concentration. For arbitrarily small cross-diffusion coefficients and for suitable exponents of the nonlinear diffusion terms, the global-in-time existence of weak solutions is proved, thus preventing finite-time blow up of the cell density. The global existence result also holds for linear and fast diffusion of the cell density in a certain parameter range in three dimensions. Furthermore, we show L∞ bounds for the solutions to the parabolic-elliptic system. Sufficient conditions leading to the asymptotic stability of the constant steady state are given for a particular choice of the nonlinear diffusion exponents. Numerical experiments in two and three space dimensions illustrate the theoretical results. © 2012 World Scientific Publishing Company.

  16. Atomic-layer-deposited WNxCy thin films as diffusion barrier for copper metallization

    Science.gov (United States)

    Kim, Soo-Hyun; Oh, Su Suk; Kim, Ki-Bum; Kang, Dae-Hwan; Li, Wei-Min; Haukka, Suvi; Tuominen, Marko

    2003-06-01

    The properties of WNxCy films deposited by atomic layer deposition (ALD) using WF6, NH3, and triethyl boron as source gases were characterized as a diffusion barrier for copper metallization. It is noted that the as-deposited film shows an extremely low resistivity of about 350 μΩ cm with a film density of 15.37 g/cm3. The film composition measured from Rutherford backscattering spectrometry shows W, C, and N of ˜48, 32, and 20 at. %, respectively. Transmission electron microscopy analyses show that the as-deposited film is composed of face-centered-cubic phase with a lattice parameter similar to both β-WC1-x and β-W2N with an equiaxed microstructure. The barrier property of this ALD-WNxCy film at a nominal thickness of 12 nm deposited between Cu and Si fails only after annealing at 700 °C for 30 min.

  17. Diffusion-controlled intergranular penetration and embrittlement of copper by liquid bismuth between 300 and 600 Celsius degrees

    International Nuclear Information System (INIS)

    Laporte, V.

    2005-02-01

    Hybrid reactors are a new concept for energy production and nuclear waste treatment. Among other requirements, structural materials have to withstand liquid metal embrittlement. This thesis aimed therefore to identify the controlling mechanism for the intergranular embrittlement of copper in contact with liquid bismuth. Scanning electron microscopy, Auger electron spectroscopy, X-ray photoelectron spectroscopy and Rutherford backscattering spectroscopy have been used to analyze fracture surfaces of both copper polycrystals and a copper bicrystal (symmetric tilt boundary 50 degrees ). These analyses reveal both parabolic intergranular penetration kinetics and a maximal intergranular bismuth concentration that is less than two monolayers equivalent. These two results allow us to identify grain boundary diffusion as the controlling mechanism for the intergranular penetration of copper by liquid bismuth between 300 and 600 Celsius degrees, showing the absence of perfect grain boundary wetting. (author)

  18. Molecular dynamics study of dislocation cores in copper: structure and diffusion at high temperatures

    International Nuclear Information System (INIS)

    Huang, Jin

    1989-01-01

    The variation of the core structure of an easy glide dislocation with temperature and its influence on the stacking fault energy (γ) have been investigated for the first time by molecular-dynamics simulation in copper. The calculations have been performed at various temperatures, using an ab-initio pseudo-potential. Our results show that the core of the Shockley partials, into which the perfect edge dislocation dissociates, becomes increasingly extended as temperature increases. However their separation remains constant. The calculated energy values of the infinite extension stacking fault and the ribbon fault between the partials are quite different, but the evolution of the core structure does not affect the temperature dependence of the latter. We have found that a high disorder appears in the core region when temperature increases due to important anharmonicity effects of the atomic vibrations. The core structure remains solid-like for T m (T m : melting point of bulk) in spite of the high disorder. Above T m , the liquid nucleus germinates in the core region, and then propagates into the bulk. In addition we studied the mobility of vacancies and interstitials trapped on the partials. Although fast diffusion is thought to occur exclusively in a pipe surrounding the dislocation core, in the present study a quasi two-dimensional diffusion is observed for both defects not only in the cores but also in the stacking fault ribbon. On the opposite of current assumptions, the activation energy for diffusion is found to be identical for both defects, which may therefore comparably contribute to mass transport along the dislocations. (author) [fr

  19. Brake wear from vehicles as an important source of diffuse copper pollution

    NARCIS (Netherlands)

    Hulskotte, J.H.J.; Gon, H.A.C.D. van der; Visschedijk, A.J.H.; Schaap, M.

    2007-01-01

    In this article we show that brake wear from road traffic vehicles is an important source of atmospheric (participate) copper concentrations in Europe. Consequently, brake wear also contributes significantly to deposition fluxes of copper to surface waters. We estimated the copper emission due to

  20. Preferred diffusion paths for copper electromigration by in situ transmission electron microscopy.

    Science.gov (United States)

    Oh, Young-Hwa; Kim, Sung-Il; Kim, Miyoung; Lee, Seung-Yong; Kim, Young-Woon

    2017-10-01

    Ionic transport in the reverse direction of an electric field is caused by momentum transfer from free electrons to metal ions, i.e., electromigration (EM), which is a critical factor leading to copper (Cu) interconnect failure in integrated circuits under extreme operating conditions. We investigated Cu self-diffusion paths under electrical bias using in situ transmission electron microscopy (TEM). An electric current was applied to multigrain Cu lines in the TEM instrument for durations of up to the order of 10 4 s to trace EM-induced Cu movement around voids and hillocks. Combining this approach with scanning nanobeam diffraction, we observed that high-angle grain boundaries exposed to the free surface are the most favored paths for Cu EM, rather than a specific orientation within the grain. On hillocks of accumulated Cu atoms, we directly observed grain growth, accompanied by the formation of Σ7 high-mobile and Σ3 twin coincidence site lattice boundaries for effective growth. This study provides insight into the EM mechanism to improve the reliability of metal interconnect design. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Atomic-layer-deposited WNxCy thin films as diffusion barrier for copper metallization

    International Nuclear Information System (INIS)

    Kim, Soo-Hyun; Oh, Su Suk; Kim, Ki-Bum; Kang, Dae-Hwan; Li, Wei-Min; Haukka, Suvi; Tuominen, Marko

    2003-01-01

    The properties of WN x C y films deposited by atomic layer deposition (ALD) using WF 6 , NH 3 , and triethyl boron as source gases were characterized as a diffusion barrier for copper metallization. It is noted that the as-deposited film shows an extremely low resistivity of about 350 μΩ cm with a film density of 15.37 g/cm 3 . The film composition measured from Rutherford backscattering spectrometry shows W, C, and N of ∼48, 32, and 20 at. %, respectively. Transmission electron microscopy analyses show that the as-deposited film is composed of face-centered-cubic phase with a lattice parameter similar to both β-WC 1-x and β-W 2 N with an equiaxed microstructure. The barrier property of this ALD-WN x C y film at a nominal thickness of 12 nm deposited between Cu and Si fails only after annealing at 700 deg. C for 30 min

  2. Disorder effect on heat capacity, self-diffusion coefficient, and choosing best potential model for melting temperature, in gold–copper bimetallic nanocluster with 55 atoms

    International Nuclear Information System (INIS)

    Taherkhani, Farid; Akbarzadeh, Hamed; Feyzi, Mostafa; Rafiee, Hamid Reza

    2015-01-01

    Molecular dynamics simulation has been implemented for doping effect on melting temperature, heat capacity, self-diffusion coefficient of gold–copper bimetallic nanostructure with 55 total gold and copper atom numbers and its bulk alloy. Trend of melting temperature for gold–copper bimetallic nanocluster is not same as melting temperature copper–gold bulk alloy. Molecular dynamics simulation of our result regarding bulk melting temperature is consistence with available experimental data. Molecular dynamics simulation shows that melting temperature of gold–copper bimetallic nanocluster increases with copper atom fraction. Semi-empirical potential model and quantum Sutton–Chen potential models do not change melting temperature trend with copper doping of gold–copper bimetallic nanocluster. Self-diffusion coefficient of copper atom is greater than gold atom in gold–copper bimetallic nanocluster. Semi-empirical potential within the tight-binding second moment approximation as new application potential model for melting temperature of gold–copper bulk structure shows better result in comparison with EAM, Sutton–Chen potential, and quantum Sutton–Chen potential models

  3. Ergothioneine prevents copper-induced oxidative damage to DNA and protein by forming a redox-inactive ergothioneine-copper complex.

    Science.gov (United States)

    Zhu, Ben-Zhan; Mao, Li; Fan, Rui-Mei; Zhu, Jun-Ge; Zhang, Ying-Nan; Wang, Jing; Kalyanaraman, Balaraman; Frei, Balz

    2011-01-14

    Ergothioneine (2-mercaptohistidine trimethylbetaine) is a naturally occurring amino acid analogue found in up to millimolar concentrations in several tissues and biological fluids. However, the biological functions of ergothioneine remain incompletely understood. In this study, we investigated the role of ergothioneine in copper-induced oxidative damage to DNA and protein, using two copper-containing systems: Cu(II) with ascorbate and Cu(II) with H(2)O(2) [0.1 mM Cu(II), 1 mM ascorbate, and 1 mM H(2)O(2)]. Oxidative damage to DNA and bovine serum albumin was measured as strand breakage and protein carbonyl formation, respectively. Ergothioneine (0.1-1.0 mM) provided strong, dose-dependent protection against oxidation of DNA and protein in both copper-containing systems. In contrast, only limited protection was observed with the purported hydroxyl radical scavengers, dimethyl sulfoxide and mannitol, even at concentrations as high as 100 mM. Ergothioneine also significantly inhibited copper-catalyzed oxidation of ascorbate and competed effectively with histidine and 1,10-phenanthroline for binding of cuprous copper, but not cupric copper, as demonstrated by UV-visible and low-temperature electron spin resonance techniques. We conclude that ergothioneine is a potent, natural sulfur-containing antioxidant that prevents copper-dependent oxidative damage to biological macromolecules by forming a redox-inactive ergothioneine-copper complex.

  4. Synergy and Diffusion with a Borax-Copper Hydroxide Groundline Preservative: 20 Year Update

    Science.gov (United States)

    Stan Lebow; Bessie Woodward; Bill Abbott; Mike West

    2014-01-01

    A groundline remedial treatment containing 3.1% copper hydroxide (2% elemental copper) and 40% sodium tetraborate decahydrate (borax) was applied to unseasoned pine posts prior to placement in a test site in southern Mississippi. The soundness of the posts was periodically evaluated using a push test. After 3.5, 6.5, 10, 15 and 20 years, sections were taken from two...

  5. The role of oxygen in the deposition of copper–calcium thin film as diffusion barrier for copper metallization

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Zhinong, E-mail: znyu@bit.edu.cn [School of Optoelectronics and Beijing Engineering Research Center of Mixed Reality and Advanced Display, Beijing Institute of Technology, Beijing 100081 (China); Ren, Ruihuang [School of Optoelectronics and Beijing Engineering Research Center of Mixed Reality and Advanced Display, Beijing Institute of Technology, Beijing 100081 (China); Xue, Jianshe; Yao, Qi; Li, Zhengliang; Hui, Guanbao [Beijing BOE Optoelectronics Technology Co., Ltd, Beijing 100176 (China); Xue, Wei [School of Optoelectronics and Beijing Engineering Research Center of Mixed Reality and Advanced Display, Beijing Institute of Technology, Beijing 100081 (China)

    2015-02-15

    Highlights: • The CuCa film as the diffusion barrier of Cu film improves the adhesion of Cu film. • The introduction of oxygen into the deposition of CuCa film is necessary to improve the adhesion of Cu film. • The CuCa alloy barrier layer deposited at oxygen atmosphere has perfect anti-diffusion between Cu film and substrate. - Abstract: The properties of copper (Cu) metallization based on copper–calcium (CuCa) diffusion barrier as a function of oxygen flux in the CuCa film deposition were investigated in view of adhesion, diffusion and electronic properties. The CuCa film as the diffusion barrier of Cu film improves the adhesion of Cu film, however, and increases the resistance of Cu film. The introduction of oxygen into the deposition of CuCa film induces the improvement of adhesion and crystallinity of Cu film, but produces a slight increase of resistance. The increased resistance results from the partial oxidation of Cu film. The annealing process in vacuum further improves the adhesion, crystallinity and conductivity of Cu film. X-ray diffraction (XRD) and Auger electron spectroscopy (AES) show that the CuCa alloy barrier layer deposited at oxygen atmosphere has perfect anti-diffusion between Cu film and substrate due to the formation of Ca oxide in the interface of CuCa/substrate.

  6. Failure Analysis of Pitted Copper Pipes Used in Underground Water and Preventive Measures

    Science.gov (United States)

    Nam, Gi-ho; Lee, Jong-kwon; Kim, Kyung-ja

    2018-03-01

    This study performed an experiment on the causes of pitting corrosion in a copper tubing used for a sprinkler system. Corrosion products of a copper tubing that sustained pitting corrosion were collected and cultured in Culture medium [Luria-Bertani, Brain heart infusion, Tryptic soy broth (TSB), R2A]. Four types of bacteria were found through identification: Micrococcus luteus sp (species)., Staphylococcus sp., Sphingomonas sp., and Bacillus sp. The copper toxicity test was performed for each microorganism. Among the four microorganisms, Micrococcus luteus sp. showed good growth in the environment containing copper ions. On the immersion test, changes in pH and Optical density were measured; On the inductively coupled plasma optical emission spectrometry test, the copper concentration of each culture medium was measured. The surface of each copper sample was observed using a scanning electron microscope. The corrosion potential of a copper sample, after 48 h exposure of the TSB medium containing Micrococcus luteus sp., was measured using a potentiodynamic polarization experiment. The next experiment was conducted to prevent microbial corrosion by suppressing the growth of microorganisms. Six 30 ml TSB culture media with controlled pH value of 4, 5, 6, 7, 8, and 9 through HCl and NaOH were manufactured. Then the microorganisms were cultured in 37 °C 133 rpm, of which the growth status was checked every 24 h for 3 days. It was found that microorganisms did not grow on culture media with the pH value of 6 and lower. The same experiment conducted on culture media controlled with acetic acid, nitric acid, and sulfuric acid, also showed no growth of microorganisms on media with pH value of 6 and lower. Six 5 ml TSB culture media each containing 0.5, 0.25, 0.125, 0.0625, 0.0312%, and 0.0156% NaOCl and NaOBr as germicides were manufactured. 0.01 μl of microorganisms were inoculated on the media and cultured in 37 °C for 48 h. It was found that microorganisms did not

  7. Controlling molecular condensation/diffusion of copper phthalocyanine by local electric field induced with scanning tunneling microscope tip

    Science.gov (United States)

    Nagaoka, Katsumi; Yaginuma, Shin; Nakayama, Tomonobu

    2018-02-01

    We have discovered the condensation/diffusion phenomena of copper phthalocyanine (CuPc) molecules controlled with a pulsed electric field induced by the scanning tunneling microscope tip. This behavior is not explained by the conventional induced dipole model. In order to understand the mechanism, we have measured the electronic structure of the molecule by tunneling spectroscopy and also performed theoretical calculations on molecular orbitals. These data clearly indicate that the molecule is positively charged owing to charge transfer to the substrate, and that hydrogen bonding exists between CuPc molecules, which makes the molecular island stable.

  8. Investigations of the interactions of silicon dioxide with copper-aluminum alloy used as an adhesion promoter and diffusion barrier for copper metallization on silicon dioxide

    Science.gov (United States)

    Wang, Pei-I.

    This study explores the concept of alloying copper with Al in order to impart properties that will make Cu useful for interconnect applications in ICs. The advantages of using Al as the alloying element lies in the thermodynamically favored interaction of Al with the underlying dielectric and with the O 2 at the surface of pure Cu thus achieving both the adhesion and passivation. This approach has been shown to generate an ultra thin interfacial layer, which acts as an adhesion promoter and diffusion barrier against Cu migration in the dielectric, without significantly affecting the resistivity of Cu. An emphasis has been placed to examine (a) the interaction of Al (from the Cu-Al alloy) with SiO2 at the alloy-SiO2 interface, (b) the Al migration to surface of the alloy or pure Cu if used, and (c) the impact of such migration on the bulk Cu film and passivation on the surface. In this work, sputtered Cu-Al (1--5 at%), with a resistivity in the range of 5--6 muO-cm, were studied as diffusion barriers/adhesion promoters between SiO2 and pure Cu. The films were examined in as-deposited state and after anneal at different temperatures for varying times and in different ambients by the use of surface and interface characterization techniques, Rutherford backscattering spectrometry (RBS) and secondary ion mass spectroscopy (SIMS), and resistance measurements together with metal-oxide-silicon (MOS) capacitor studies. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were also used to elucidate the structure. The results elucidate the mechanisms of Al movement and interaction with the interface SiO2 and O2 on surface and indicate that films of Cu doped with Al do act as a suitable diffusion barrier and adhesion promoter between SiO2 and Cu.

  9. Supporting the diffusion of healthy public policy in Canada: the Prevention Policies Directory.

    Science.gov (United States)

    Politis, Christopher E; Halligan, Michelle H; Keen, Deb; Kerner, Jon F

    2014-01-01

    Healthy public policy plays an essential role in a comprehensive public health approach to preventing cancer and chronic disease. Public policies spread through the 'policy diffusion' process, enabling governments to learn from another's enacted policy solutions. The Prevention Policies Directory (the Directory), an online database of municipal, provincial/territorial, and federal cancer and chronic disease prevention policies from across Canada, was developed to facilitate the diffusion of healthy public policies and support the work of prevention researchers, practitioners, and policy specialists. This information technology solution was implemented, through a participatory engagement approach, as a communication channel or policy knowledge transfer tool. It also addressed the intrinsic shortcomings of environmental scanning for policy surveillance and monitoring. A combination of quantitative web metrics and qualitative anecdotal evidence have illustrated that the Directory is becoming an important tool for healthy public policy surveillance and policy diffusion in Canada.

  10. Segregation and diffusion of deffects induced by radiation in binary copper alloys

    International Nuclear Information System (INIS)

    Monteiro, W.A.

    1984-01-01

    Actually considerable theoretical and experimental progress has been made in establishing and in understanding the general feactures of the Radiation Induced Solute Difusion or Segregation such as its temperature, time and displacement rate dependence and the effects of some important materials factors such as the initial solute misfit. During irradiation, the local alloy compositions will change by defect flux driven, non-equilibrium segregation near sinks such as voids, external surfaces and grain boundaries and the compositional change are likely to influence a number of properties and phenomena important to Thermonuclear Reactors, as for example, Ductility, Corrosion, Stress, Corrosion Craking, Sputtering and Blistering. Our work is correlated with the 1 MeV electrons irradiations effects in Copper alloys where the alloying elements are Be, Pt, Sn. These three elements are undersized, similar and oversized relating the Copper atom radius, respectively. How starts and develops the Segregation Induced by Irradiation 'In Situ' with help of the High Voltage Electron Microscopy as technique. (Author) [pt

  11. Solid State Field-Assisted Diffusion of Copper in Multi-Component Tellurite Glass

    Czech Academy of Sciences Publication Activity Database

    Stepanov, B.; Ren, J.; Wágner, T.; Lorinčík, Jan; Frumar, M.; Churbanov, M.; Chigirinsky, Y.

    2011-01-01

    Roč. 94, č. 7 (2011), 1986-1988 ISSN 0002-7820 Institutional research plan: CEZ:AV0Z20670512 Keywords : Solid state diffusion * Secondary Ion Mass Spectrometry * Tellurite glass Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.272, year: 2011

  12. Study of Nickel Silicide as a Copper Diffusion Barrier in Monocrystalline Silicon Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Kale, Abhijit; Beese, Emily; Saenz, Theresa; Warren, Emily; Nemeth, William; Young, David; Marshall, Alexander; Florent, Karine; Kurinec, Santosh K.; Agarwal, Sumit; Stradins, Pauls

    2016-11-21

    NiSi as a conductive diffusion barrier to silicon has been studied. We demonstrate that the NiSi films formed using the single step annealing process are as good as the two step process using XRD and Raman. Quality of NiSi films formed using e-beam Ni and electroless Ni process has been compared. Incomplete surface coverage and presence of constituents other than Ni are the main challenges with electroless Ni. We also demonstrate that Cu reduces the thermal stability of NiSi films. The detection of Cu has proven to be difficult due to temperature limitations.

  13. The impact of porosity on the formation of manganese based copper diffusion barrier layers on low-κ dielectric materials

    International Nuclear Information System (INIS)

    McCoy, A P; Bogan, J; Walsh, L; Byrne, C; O’Connor, R; Hughes, G; Woicik, J C

    2015-01-01

    This work investigates the impact of porosity in low-κ dielectric materials on the chemical and structural properties of deposited Mn thin films for copper diffusion barrier layer applications. X-ray photoelectron spectrscopy (XPS) results highlight the difficulty in distinguishing between the various Mn oxidation states which form at the interlayer dielectric (ILD)/Mn interface. The presence of MnSiO 3 and MnO were identified using x-ray absorption spectroscopy (XAS) measurements on both porous and non-porous dielectric materials with evidence of Mn 2 O 3 and Mn 3 O 4 in the deposited film on the latter surface. It is shown that a higher proportion of deposited Mn converts to Mn silicate on an ILD film which has 50% porosity compared with the same dielectric material with no porosity, which is attributed to an enhanced chemical interaction with the effective larger surface area of porous dielectric materials. Transmission electron microscopy (TEM) and energy-dispersive x-ray spectroscopy (EDX) data shows that the Mn overlayer remains predominately surface localised on both porous and non-porous materials. (paper)

  14. The plant decapeptide OSIP108 prevents copper-induced toxicity in various models for Wilson disease

    Energy Technology Data Exchange (ETDEWEB)

    Spincemaille, Pieter [Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Kasteelpark Arenberg 20, 3001 Heverlee (Belgium); Pham, Duc-Hung [Laboratory for Molecular Biodiscovery, KU Leuven, Campus Gasthuisberg, Herestraat 49, O and N2, 3000 Leuven (Belgium); Chandhok, Gursimran [Clinic for Transplantation Medicine, Münster University Hospital, Albert-Schweitzer-Campus 1, Building A14, D-48149 Münster (Germany); Verbeek, Jef [Department of Hepatology and Metabolic Center, University Hospital Gasthuisberg, Herestraat 49, 3000 Leuven (Belgium); Zibert, Andree [Clinic for Transplantation Medicine, Münster University Hospital, Albert-Schweitzer-Campus 1, Building A14, D-48149 Münster (Germany); Libbrecht, Louis [Department of Hepatology and Metabolic Center, University Hospital Gasthuisberg, Herestraat 49, 3000 Leuven (Belgium); Department of Pathology, University Hospital Ghent, De Pintelaan 185, 9000 Ghent (Belgium); Schmidt, Hartmut [Clinic for Transplantation Medicine, Münster University Hospital, Albert-Schweitzer-Campus 1, Building A14, D-48149 Münster (Germany); Esguerra, Camila V.; Witte, Peter A.M. de [Laboratory for Molecular Biodiscovery, KU Leuven, Campus Gasthuisberg, Herestraat 49, O and N2, 3000 Leuven (Belgium); Cammue, Bruno P.A., E-mail: bruno.cammue@biw.kuleuven.be [Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Kasteelpark Arenberg 20, 3001 Heverlee (Belgium); Department of Plant Systems Biology, VIB, Technologiepark 927, 9052 Ghent (Belgium); Cassiman, David [Department of Hepatology and Metabolic Center, University Hospital Gasthuisberg, Herestraat 49, 3000 Leuven (Belgium); Thevissen, Karin [Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Kasteelpark Arenberg 20, 3001 Heverlee (Belgium)

    2014-10-15

    Background: Wilson disease (WD) is caused by accumulation of excess copper (Cu) due to a mutation in the gene encoding the liver Cu transporter ATP7B, and is characterized by acute liver failure or cirrhosis and neuronal cell death. We investigated the effect of OSIP108, a plant derived decapeptide that prevents Cu-induced apoptosis in yeast and human cells, on Cu-induced toxicity in various mammalian in vitro models relevant for WD and in a Cu-toxicity zebrafish larvae model applicable to WD. Methods: The effect of OSIP108 was evaluated on viability of various cell lines in the presence of excess Cu, on liver morphology of a Cu-treated zebrafish larvae strain that expresses a fluorescent reporter in hepatocytes, and on oxidative stress levels in wild type AB zebrafish larvae. Results: OSIP108 increased not only viability of Cu-treated CHO cells transgenically expressing ATP7B and the common WD-causing mutant ATP7B{sup H1069Q}, but also viability of Cu-treated human glioblastoma U87 cells. Aberrancies in liver morphology of Cu-treated zebrafish larvae were observed, which were further confirmed as Cu-induced hepatotoxicity by liver histology. Injections of OSIP108 into Cu-treated zebrafish larvae significantly increased the amount of larvae with normal liver morphology and decreased Cu-induced production of reactive oxygen species. Conclusions: OSIP108 prevents Cu-induced toxicity in in vitro models and in a Cu-toxicity zebrafish larvae model applicable to WD. General significance: All the above data indicate the potential of OSIP108 as a drug lead for further development as a novel WD treatment. - Highlights: • Wilson disease (WD) is characterized by accumulation of toxic copper (Cu). • OSIP108 increases viability of Cu-treated cellular models applicable to WD. • OSIP108 injections preserve liver morphology of Cu-treated zebrafish larvae. • OSIP108 injections into zebrafish larvae abrogates Cu-induced oxidative stress.

  15. The plant decapeptide OSIP108 prevents copper-induced toxicity in various models for Wilson disease.

    Science.gov (United States)

    Spincemaille, Pieter; Pham, Duc-Hung; Chandhok, Gursimran; Verbeek, Jef; Zibert, Andree; Libbrecht, Louis; Schmidt, Hartmut; Esguerra, Camila V; de Witte, Peter A M; Cammue, Bruno P A; Cassiman, David; Thevissen, Karin

    2014-10-15

    Wilson disease (WD) is caused by accumulation of excess copper (Cu) due to a mutation in the gene encoding the liver Cu transporter ATP7B, and is characterized by acute liver failure or cirrhosis and neuronal cell death. We investigated the effect of OSIP108, a plant derived decapeptide that prevents Cu-induced apoptosis in yeast and human cells, on Cu-induced toxicity in various mammalian in vitro models relevant for WD and in a Cu-toxicity zebrafish larvae model applicable to WD. The effect of OSIP108 was evaluated on viability of various cell lines in the presence of excess Cu, on liver morphology of a Cu-treated zebrafish larvae strain that expresses a fluorescent reporter in hepatocytes, and on oxidative stress levels in wild type AB zebrafish larvae. OSIP108 increased not only viability of Cu-treated CHO cells transgenically expressing ATP7B and the common WD-causing mutant ATP7B(H1069Q), but also viability of Cu-treated human glioblastoma U87 cells. Aberrancies in liver morphology of Cu-treated zebrafish larvae were observed, which were further confirmed as Cu-induced hepatotoxicity by liver histology. Injections of OSIP108 into Cu-treated zebrafish larvae significantly increased the amount of larvae with normal liver morphology and decreased Cu-induced production of reactive oxygen species. OSIP108 prevents Cu-induced toxicity in in vitro models and in a Cu-toxicity zebrafish larvae model applicable to WD. All the above data indicate the potential of OSIP108 as a drug lead for further development as a novel WD treatment. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Permanence and diffusion of borax-copper hydroxide remedial preservative applied to unseasoned pine posts : 10 year update

    Science.gov (United States)

    Douglas Crawford; Stan Lebow; Mike West; Bill Abbott

    2005-01-01

    In 1993, unseasoned pine posts were treated with groundline remedial treatment containing 3.1% copper hydroxide and 40% sodium tetraborate decahydrate (borax). The soundness of the posts was periodically evaluated using a push test. After 3.5, 6.5, and 10 years, sections were taken from two posts to determine retention of borax and copper hydroxide below ground to 36...

  17. Polymeric hydrogen diffusion barrier, high-pressure storage tank so equipped, method of fabricating a storage tank and method of preventing hydrogen diffusion

    Science.gov (United States)

    Lessing, Paul A [Idaho Falls, ID

    2008-07-22

    An electrochemically active hydrogen diffusion barrier which comprises an anode layer, a cathode layer, and an intermediate electrolyte layer, which is conductive to protons and substantially impermeable to hydrogen. A catalytic metal present in or adjacent to the anode layer catalyzes an electrochemical reaction that converts any hydrogen that diffuses through the electrolyte layer to protons and electrons. The protons and electrons are transported to the cathode layer and reacted to form hydrogen. The hydrogen diffusion barrier is applied to a polymeric substrate used in a storage tank to store hydrogen under high pressure. A storage tank equipped with the electrochemically active hydrogen diffusion barrier, a method of fabricating the storage tank, and a method of preventing hydrogen from diffusing out of a storage tank are also disclosed.

  18. Polymeric hydrogen diffusion barrier, high-pressure storage tank so equipped, method of fabricating a storage tank and method of preventing hydrogen diffusion

    Science.gov (United States)

    Lessing, Paul A.

    2004-09-07

    An electrochemically active hydrogen diffusion barrier which comprises an anode layer, a cathode layer, and an intermediate electrolyte layer, which is conductive to protons and substantially impermeable to hydrogen. A catalytic metal present in or adjacent to the anode layer catalyzes an electrochemical reaction that converts any hydrogen that diffuses through the electrolyte layer to protons and electrons. The protons and electrons are transported to the cathode layer and reacted to form hydrogen. The hydrogen diffusion barrier is applied to a polymeric substrate used in a storage tank to store hydrogen under high pressure. A storage tank equipped with the electrochemically active hydrogen diffusion barrier, a method of fabricating the storage tank, and a method of preventing hydrogen from diffusing out of a storage tank are also disclosed.

  19. In Situ XPS Chemical Analysis of MnSiO3 Copper Diffusion Barrier Layer Formation and Simultaneous Fabrication of Metal Oxide Semiconductor Electrical Test MOS Structures.

    Science.gov (United States)

    Byrne, Conor; Brennan, Barry; McCoy, Anthony P; Bogan, Justin; Brady, Anita; Hughes, Greg

    2016-02-03

    Copper/SiO2/Si metal-oxide-semiconductor (MOS) devices both with and without a MnSiO3 barrier layer at the Cu/SiO2 interface have been fabricated in an ultrahigh vacuum X-ray photoelectron spectroscopy (XPS) system, which allows interface chemical characterization of the barrier formation process to be directly correlated with electrical testing of barrier layer effectiveness. Capacitance voltage (CV) analysis, before and after tube furnace anneals of the fabricated MOS structures showed that the presence of the MnSiO3 barrier layer significantly improved electric stability of the device structures. Evidence of improved adhesion of the deposited copper layer to the MnSiO3 surface compared to the clean SiO2 surface was apparent both from tape tests and while probing the samples during electrical testing. Secondary ion mass spectroscopy (SIMS) depth profiling measurements of the MOS test structures reveal distinct differences of copper diffusion into the SiO2 dielectric layers following the thermal anneal depending on the presence of the MnSiO3 barrier layer.

  20. Planning the diffusion of a neck-injury prevention programme among community rugby union coaches.

    Science.gov (United States)

    Donaldson, Alex; Poulos, Roslyn G

    2014-01-01

    This paper describes the development of a theory-informed and evidence-informed, context-specific diffusion plan for the Mayday Safety Procedure (MSP) among community rugby coaches in regional New South Wales, Australia. Step 5 of Intervention Mapping was used to plan strategies to enhance MSP adoption and implementation. Coaches were identified as the primary MSP adopters and implementers within a system including administrators, players and referees. A local advisory group was established to ensure context relevance. Performance objectives (eg, attend MSP training for coaches) and determinants of adoption and implementation behaviour (eg, knowledge, beliefs, skills and environment) were identified, informed by Social Cognitive Theory. Adoption and implementation matrices were developed and change-objectives for coaches were identified (eg, skills to deliver MSP training to players). Finally, intervention methods and specific strategies (eg, coach education, social marketing and policy and by-law development) were identified based on advisory group member experience, evidence of effective coach safety behaviour-change interventions and Diffusion of Innovations theory. This is the first published example of a systematic approach to plan injury prevention programme diffusion in community sports. The key strengths of this approach were an effective researcher-practitioner partnership; actively engaging local sports administrators; targeting specific behaviour determinants, informed by theory and evidence; and taking context-related practical strengths and constraints into consideration. The major challenges were the time involved in using a systematic diffusion planning approach for the first time; and finding a planning language that was acceptable and meaningful to researchers and practitioners.

  1. Diffusive gradient in thin films technique for assessment of cadmium and copper bioaccessibility to radish (Raphanus sativus)

    Czech Academy of Sciences Publication Activity Database

    Dočekalová, H.; Škarpa, P.; Dočekal, Bohumil

    2015-01-01

    Roč. 134, March (2015), s. 153-157 ISSN 0039-9140 R&D Projects: GA ČR GAP503/10/2002 Institutional support: RVO:68081715 Keywords : radish * cadmium * copper * DGT technique * bioaccesibility Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.035, year: 2015

  2. Prevention of iron- and copper-mediated DNA damage by catecholamine and amino acid neurotransmitters, L-DOPA, and curcumin: metal binding as a general antioxidant mechanism.

    Science.gov (United States)

    García, Carla R; Angelé-Martínez, Carlos; Wilkes, Jenna A; Wang, Hsiao C; Battin, Erin E; Brumaghim, Julia L

    2012-06-07

    Concentrations of labile iron and copper are elevated in patients with neurological disorders, causing interest in metal-neurotransmitter interactions. Catecholamine (dopamine, epinephrine, and norepinephrine) and amino acid (glycine, glutamate, and 4-aminobutyrate) neurotransmitters are antioxidants also known to bind metal ions. To investigate the role of metal binding as an antioxidant mechanism for these neurotransmitters, L-dihydroxyphenylalanine (L-DOPA), and curcumin, their abilities to prevent iron- and copper-mediated DNA damage were quantified, cyclic voltammetry was used to determine the relationship between their redox potentials and DNA damage prevention, and UV-vis studies were conducted to determine iron and copper binding as well as iron oxidation rates. In contrast to amino acid neurotransmitters, catecholamine neurotransmitters, L-DOPA, and curcumin prevent significant iron-mediated DNA damage (IC(50) values of 3.2 to 18 μM) and are electrochemically active. However, glycine and glutamate are more effective at preventing copper-mediated DNA damage (IC(50) values of 35 and 12.9 μM, respectively) than L-DOPA, the only catecholamine to prevent this damage (IC(50) = 73 μM). This metal-mediated DNA damage prevention is directly related to the metal-binding behaviour of these compounds. When bound to iron or copper, the catecholamines, amino acids, and curcumin significantly shift iron oxidation potentials and stabilize Fe(3+) over Fe(2+) and Cu(2+) over Cu(+), a factor that may prevent metal redox cycling in vivo. These results highlight the disparate antioxidant activities of neurotransmitters, drugs, and supplements and highlight the importance of considering metal binding when identifying antioxidants to treat and prevent neurodegenerative disorders.

  3. Prevention of PCDD/Fs emission from a municipal wastewater sludge incinerator through enhanced control of copper aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Pena, E.; Elcoroaristizabal, S.; Larrion, M.; Legarreta, J. A.; Gutierrez-Canas, C.

    2012-11-01

    Municipal wastewater sludge incineration (MWSI) leads to products of incomplete combustion, including chlorinated species such as dioxins and furans (PCDD/Fs). Other pollutants, such as heavy metals (HM), are released too as a consequence of feed traces, which depend on the specific activities of each area. The main aim of this work is to determine whether the early separation of the potential catalysts on the PCDD/Fs formation HM as copper or zinc offers a promising way to prevent the emission of these trace pollutants, considering that the current end-of-pipe measures don't ensure their stable emission. Experimental results cover the size distributed target metal contents along the incineration line. These results show a high concentration of copper in the most penetrating aerosol size range of the electrostatic precipitator (0.6 {mu}m - 1.0 {mu}m), and how low emission values of both, total and metallic aerosol (mass basis), are compatible with irregular and unexplained outliers of PCDD/Fs emission. (Author) 39 refs.

  4. INVESTIGATION OF CLINOPTILOLITE MODIFIED WITH IONS OF HYDROGEN, PALLADIUM(II, AND COPPER(II BY IR AND DIFFUSE REFLECTANCE SPECTRAL METHODS

    Directory of Open Access Journals (Sweden)

    T. L. Rakytskaya

    2016-07-01

    Full Text Available Changes appeared in IR and diffuse reflectance UV-vis spectra of clinoptilolite as a result of its modification by boiling in nitric acid solutions (0.25-3 M and anchoring active components on it were analyzed. As was shown by IR spectroscopy, the increase in acid concentration caused a high-frequency shift of the band attributed to asymmetric stretching vibrations of the Si-O-Al fragment due to the clinoptilolite dealumination. The values of this shift were not changed after active components anchoring on the acid modified clinoptilolite samples.  The band of deformation vibrations of OH groups in water molecules (at 1633 cm-1 for natural clinoptilolite was weakly affected (a slight high-frequency shift by the acid concentration increase and remained practically unaffected by anchoring palladium and copper ions. However,  the effect of Pd(II and Cu(II anchoring on IR spectra could be observed through a low-frequency shift of the band characterizing stretching vibration νОН of OH groups in water molecules indicating some disturbance of hydrogen bonds in H2O molecules and a change in their energy. The UV region of diffuse reflectance UV-vis spectra of all anchored catalyst samples showed the appearance of new intense bands at 224-226, 279-284, and 327-334 nm which were absent Pd-Cu complexes which attendance is necessary for catalytic low-temperature oxidation of carbon monoxide with air oxygen. It should be noted that a new band appeared at 351-363 nm would be assigned to individual Pd(II indicating that some portion of palladium(II ions did not participate in the formation of the catalytically active bimetallic Pd-Cu complexes. The presence of individual palladium(II was confirmed by the fact that only the bends characteristic of square planar palladium(II complexes were observed in the palladium(II absorbing region in the visible part of diffuse reflectance UV-vis spectra. Additionaly, theses spectra also contained the bends corresponding

  5. Thermal stability of amorphous tungsten/tungsten nitride synthesis using HFCVD as a diffusion barrier for copper

    Energy Technology Data Exchange (ETDEWEB)

    Asgary, Somayeh; Hantehzadeh, Mohammad Reza; Ghoranneviss, Mahmood [Islamic Azad University, Plasma Physics Research Center, Science and Research Branch, Tehran (Iran, Islamic Republic of); Boochani, Arash [Islamic Azad University, Department of Physics, Kermanshah Branch, Kermanshah (Iran, Islamic Republic of)

    2016-05-15

    The amorphous W/WN bi-layer with excellent thermal stability was successfully prepared by hot-filament chemical vapor deposition method on SiO{sub 2}/Si substrate. It was found that the W/WN bi-layer is technological importance because of its low resistivity and good diffusion barrier properties between Cu and Si up to 700 C for 30 min. The thermal stability was evaluated by X-ray diffractometer (XRD) and scanning electron microscope. The XRD results show that the Cu{sub 3}Si phase was formed by Cu diffusion through W/WN barrier for the 800 C annealed sample. The formation of the Cu-Si compounds denotes the failure of the W/WN diffusion barrier with rapid increase in sheet resistance of the film. The microstructure of the interface between W/WN and Cu reflects the stability and breakdown of the barriers. The failure of this amorphous barrier occurs with heat treatment when the deposited amorphous barrier material crystallizes. The major part of Cu diffusion in polycrystalline structure with disordered grain boundaries is controlled by grain boundaries. AFM results indicated a rapid increase in surface roughness at the diffusion barrier failure temperature. It was found that the grain size plays an important factor to control the thermally stability of the W/WN bi-layer. (orig.)

  6. Resource consumption of a diffusion model for prevention programs: the PROSPER delivery system.

    Science.gov (United States)

    Crowley, Daniel M; Jones, Damon E; Greenberg, Mark T; Feinberg, Mark E; Spoth, Richard L

    2012-03-01

    To prepare public systems to implement evidence-based prevention programs for adolescents, it is necessary to have accurate estimates of programs' resource consumption. When evidence-based programs are implemented through a specialized prevention delivery system, additional costs may be incurred during cultivation of the delivery infrastructure. Currently, there is limited research on the resource consumption of such delivery systems and programs. In this article, we describe the resource consumption of implementing the PROSPER (PROmoting School-Community-University Partnerships to Enhance Resilience) delivery system for a period of 5 years in one state, and how the financial and economic costs of its implementation affect local communities as well as the Cooperative Extension and University systems. We used a six-step framework for conducting cost analysis, using a Cost-Procedure-Process-Outcome Analysis model (Yates, Analyzing costs, procedures, processes, and outcomes in human services: An introduction, 1996; Yates, 2009). This method entails defining the delivery System; bounding cost parameters; identifying, quantifying, and valuing systemic resource Consumption, and conducting sensitivity analysis of the cost estimates. Our analyses estimated both the financial and economic costs of the PROSPER delivery system. Evaluation of PROSPER illustrated how costs vary over time depending on the primacy of certain activities (e.g., team development, facilitator training, program implementation). Additionally, this work describes how the PROSPER model cultivates a complex resource infrastructure and provides preliminary evidence of systemic efficiencies. This work highlights the need to study the costs of diffusion across time and broadens definitions of what is essential for successful implementation. In particular, cost analyses offer innovative methodologies for analyzing the resource needs of prevention systems. Copyright © 2012 Society for Adolescent Health and

  7. Innovation in sexually transmitted disease and HIV prevention: internet and mobile phone delivery vehicles for global diffusion.

    Science.gov (United States)

    Swendeman, Dallas; Rotheram-Borus, Mary Jane

    2010-03-01

    Efficacious behavioral interventions and practices have not been universally accepted, adopted, or diffused by policy makers, administrators, providers, advocates, or consumers. Biomedical innovations for sexually transmitted disease (STD) and HIV prevention have been embraced but their effectiveness is hindered by behavioral factors. Behavioral interventions are required to support providers and consumers for adoption and diffusion of biomedical innovations, protocol adherence, and sustained prevention for other STDs. Information and communication technology such as the Internet and mobile phones can deliver behavioral components for STD/HIV prevention and care to more people at less cost. Recent innovations in STD/HIV prevention with information and communication technology-mediated behavioral supports include STD/HIV testing and partner interventions, behavioral interventions, self-management, and provider care. Computer-based and Internet-based behavioral STD/HIV interventions have demonstrated efficacy comparable to face-to-face interventions. Mobile phone STD/HIV interventions using text-messaging are being broadly utilized but more work is needed to demonstrate efficacy. Electronic health records and care management systems can improve care, but interventions are needed to support adoption. Information and communication technology is rapidly diffusing globally. Over the next 5-10 years smart-phones will be broadly disseminated, connecting billions of people to the Internet and enabling lower cost, highly engaging, and ubiquitous STD/HIV prevention and treatment support interventions.

  8. Participation and diffusion effects of a peer-intervention for HIV prevention among adults in rural Malawi.

    Science.gov (United States)

    Crittenden, Kathleen S; Kaponda, Chrissie P N; Jere, Diana L; McCreary, Linda L; Norr, Kathleen F

    2015-05-01

    This paper examines whether a peer group intervention that reduced self-reported risky behaviors for rural adults in Malawi also had impacts on non-participants in the same communities. We randomly assigned two districts to the intervention and control conditions, and conducted surveys at baseline and 18 months post-intervention using unmatched independent random samples of intervention and control communities in 2003-2006. The six-session peer group intervention was offered to same-gender groups by trained volunteers. In this analysis, we divided the post-intervention sample into three exposure groups: 243 participants and 170 non-participants from the intervention district (total n = 415) and 413 control individuals. Controlling for demographics and participation, there were significant favorable diffusion effects on five partially overlapping behavioral outcomes: partner communication, ever used condoms, unprotected sex, recent HIV test, and a community HIV prevention index. Non-participants in the intervention district had more favorable outcomes on these behaviors than survey respondents in the control district. One behavioral outcome, community HIV prevention, showed both participation and diffusion effects. Participating in the intervention had a significant effect on six psychosocial outcomes: HIV knowledge (two measures), hope, condom attitudes, and self-efficacy for community HIV prevention and for safer sex; there were no diffusion effects. This pattern of results suggests that the behavioral changes promoted in the intervention spread to others in the same community, most likely through direct contact between participants and non-participants. These findings support the idea that diffusion of HIV-related behavior changes can occur for peer group interventions in communities, adding to the body of research supporting diffusion of innovations theory as a robust approach to accelerating change. If diffusion occurs, peer group intervention may be more

  9. Field tests of the efficacy of zinc and fatty amine in preventing colonization by copper-tolerant fungi

    Science.gov (United States)

    Stan Lebow; Bessie Woodward; Steven Halverson; Michael West

    2012-01-01

    Ground-contact durability of stakes treated with acidic copper formulations was evaluated. All test formulations incorporated copper, dimethylcocoamine and propanoic acid; one set of formulations also included zinc. Sapwood stakes cut from the southern pine group were pressure-treated to a range of retentions with each formulation and placed into plots within Harrison...

  10. Prevention of PCDD/Fs emission from a municipal wastewater sludge incinerator through enhanced control of copper aerosol

    Directory of Open Access Journals (Sweden)

    Peña, E.

    2012-10-01

    Full Text Available Municipal wastewater sludge incineration (MWSI leads to products of incomplete combustion, including chlorinated species such as dioxins and furans (PCDD/Fs. Other pollutants, such as heavy metals (HM, are released too as a consequence of feed traces, which depend on the specific activities of each area. The main aim of this work is to determine whether the early separation of the potential catalysts on the PCDD/Fs formation –HM as copper or zinc– offers a promising way to prevent the emission of these trace pollutants, considering that the current end-of-pipe measures don’t ensure their stable emission. Experimental results cover the size distributed target metal contents along the incineration line. These results show a high concentration of copper in the most penetrating aerosol size range of the electrostatic precipitator (0.6 μm - 1.0 μm, and how low emission values of both, total and metallic aerosol (mass basis, are compatible with irregular and unexplained outliers of PCDD/Fs emission.

    La incineración de lodos de aguas residuales urbanas acarrea la formación de compuestos derivados de combustiones incompletas, incluyendo especies cloradas como dioxinas y furanos (PCDD/Fs. Otros contaminantes, como metales pesados, se emiten como consecuencia de las trazas del lodo, las cuales dependen de las actividades del entorno. El objetivo principal es determinar si la separación de catalizadores potenciales en reacciones de formación de PCDD/Fs (cobre o zinc puede abrir vías para prevenir la emisión de contaminantes traza, considerando que ninguna de las técnicas de prevención actuales aseguran emisiones estables de metales pesados o PCDD/Fs. Se determinan concentraciones de metales pesados segregados por tamaño de partícula a lo largo de la línea de incineración. Los resultados muestran concentraciones elevadas de cobre en el aerosol de máxima penetración del electrofiltro (0,6 μm - 1,0 μm, y cómo concentraciones

  11. Transition to finger convection in double-diffusive convection

    OpenAIRE

    Kellner, M.; Tilgner, A.

    2014-01-01

    Finger convection is observed experimentally in an electrodeposition cell in which a destabilizing gradient of copper ions is maintained against a stabilizing temperature gradient. This double-diffusive system shows finger convection even if the total density stratification is unstable. Finger convection is replaced by an ordinary convection roll if convection is fast enough to prevent sufficient heat diffusion between neighboring fingers, or if the thermal buoyancy force is less than 1/30 of...

  12. Copper and copper-nickel alloys as zebra mussel antifoulants

    Energy Technology Data Exchange (ETDEWEB)

    Dormon, J.M.; Cottrell, C.M.; Allen, D.G.; Ackerman, J.D.; Spelt, J.K. [Univ. of Toronto, Ontario (Canada)

    1996-04-01

    Copper has been used in the marine environment for decades as cladding on ships and pipes to prevent biofouling by marine mussels (Mytilus edulis L.). This motivated the present investigation into the possibility of using copper to prevent biofouling in freshwater by both zebra mussels and quagga mussels (Dreissena polymorpha and D. bugensis collectively referred to as zebra mussels). Copper and copper alloy sheet proved to be highly effective in preventing biofouling by zebra mussels over a three-year period. Further studies were conducted with copper and copper-nickel mesh (lattice of expanded metal) and screen (woven wire with a smaller hole size), which reduced the amount of copper used. Copper screen was also found to be strongly biofouling-resistant with respect to zebra mussels, while copper mesh reduced zebra mussel biofouling in comparison to controls, but did not prevent it entirely. Preliminary investigations into the mechanism of copper antifouling, using galvanic couples, indicated that the release of copper ions from the surface of the exposed metal into the surrounding water is directly or indirectly responsible for the biofouling resistance of copper.

  13. Prevention against diffuse spinal cord astrocytoma: can the Notch pathway be a novel treatment target?

    Directory of Open Access Journals (Sweden)

    Jian-jun Sun

    2015-01-01

    Full Text Available This study was designed to investigate whether the Notch pathway is involved in the development of diffuse spinal cord astrocytomas. BALB/c nude mice received injections of CD133 + and CD133− cell suspensions prepared using human recurrent diffuse spinal cord astrocytoma tissue through administration into the right parietal lobe. After 7-11 weeks, magnetic resonance imaging was performed weekly. Xenografts were observed on the surfaces of the brains of mice receiving the CD133 + cell suspension, and Notch-immunopositive expression was observed in the xenografts. By contrast, no xenografts appeared in the identical position on the surfaces of the brains of mice receiving the CD133− cell suspension, and Notch-immunopositive expression was hardly detected either. Hematoxylin-eosin staining and immunohistochemical staining revealed xenografts on the convex surfaces of the brains of mice that underwent CD133 + astrocytoma transplantation. Some sporadic astroglioma cells showed pseudopodium-like structures, which extended into the cerebral white matter. However, it should be emphasized that the subcortex xenograft with Notch-immunopositive expression was found in the fourth mouse received injection of CD133− astrocytoma cells. However, these findings suggest that the Notch pathway plays an important role in the formation of astrocytomas, and can be considered a novel treatment target for diffuse spinal cord astrocytoma.

  14. Hydrogen in oxygen-free, phosphorus-doped copper - Charging techniques, hydrogen contents and modelling of hydrogen diffusion and depth profile

    Energy Technology Data Exchange (ETDEWEB)

    Martinsson, Aasa [Swerea KIMAB, Kista (Sweden); Sandstroem, Rolf [Swerea KIMAB, Kista (Sweden); Div. of Materials Science and Engineering, KTH Royal Institute of Technology, Stockholm (Sweden); Lilja, Christina [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2013-01-15

    In Sweden spent nuclear fuel is planned to be disposed of by encapsulating in cast iron inserts protected by a copper shell. The copper can be exposed to hydrogen released during corrosion processes in the inserts. If the hydrogen is taken up by the copper, it could lead to hydrogen embrittlement. Specimens from oxygen-free copper have been hydrogen charged using two different methods. The purpose was to investigate how hydrogen could be introduced into copper in a controlled way. The thermal charging method resulted in a reduction of the initial hydrogen content. After electrochemical charging of cylindrical specimens, the measured hydrogen content was 2.6 wt. ppm which should compared with 0.6 wt. ppm before charging. The retained hydrogen after two weeks was reduced by nearly 40%. Recently the paper 'Hydrogen depth profile in phosphorus-doped, oxygen-free copper after cathodic charging' (Martinsson and Sandstrom, 2012) has been published. The paper describes experimental results for bulk specimens as well as presenting a model. Almost all the hydrogen is found to be located less than 100 {mu}m from the surface. This model is used to interpret the experimental results on foils in the present report. Since the model is fully based on fundamental equations, it can be used to analyse what happens in new situations. In this report the effect of the charging intensity, the grain size, the critical nucleus size for hydrogen bubble formation as well as the charging time are analysed.

  15. Diffusion and dissemination of evidence-based dietary srategies for the prevention of cancer

    Science.gov (United States)

    Ciliska, Donna; Robinson, Paula; Armour, Tanya; Ellis, Peter; Brouwers, Melissa; Gauld, Mary; Baldassarre, Fulvia; Raina, Parminder

    2005-01-01

    Objective The purpose was to determine what strategies have been evaluated to disseminate cancer control interventions that promote the uptake of adult healthy diet? Methods A systematic review was conducted. Studies were identified by searching MEDLINE, PREMEDLINE, Cancer LIT, EMBASE/Excerpta Medica, PsycINFO, CINAHL, the Cochrane Database of Systematic Reviews, and reference lists and by contacting technical experts. English-language primary studies were selected if they evaluated the dissemination of healthy diet interventions in individuals, healthcare providers, or institutions. Studies of children or adolescents only were excluded. Results One hundred one articles were retrieved for full text screening. Nine reports of seven distinct studies were included; four were randomized trials, one was a cohort design and three were descriptive studies. Six studies were rated as methodologically weak, and one was rated as moderate. Studies were not meta-analyzed because of heterogeneity, low methodological quality, and incomplete data reporting. No beneficial dissemination strategies were found except one that looks promising, the use of peer educators in the worksite, which led to a short-term increase in fruit and vegetable intake. Conclusions and Implications Overall, the quality of the evidence is not strong and is primarily descriptive rather than evaluative. No clear conclusions can be drawn from these data. Controlled studies are needed to evaluate dissemination strategies, and to compare dissemination and diffusion strategies with different messages and different target audiences. PMID:15819991

  16. Diffusion and dissemination of evidence-based dietary srategies for the prevention of cancer

    Directory of Open Access Journals (Sweden)

    Brouwers Melissa

    2005-04-01

    Full Text Available Abstract Objective The purpose was to determine what strategies have been evaluated to disseminate cancer control interventions that promote the uptake of adult healthy diet? Methods A systematic review was conducted. Studies were identified by searching MEDLINE, PREMEDLINE, Cancer LIT, EMBASE/Excerpta Medica, PsycINFO, CINAHL, the Cochrane Database of Systematic Reviews, and reference lists and by contacting technical experts. English-language primary studies were selected if they evaluated the dissemination of healthy diet interventions in individuals, healthcare providers, or institutions. Studies of children or adolescents only were excluded. Results One hundred one articles were retrieved for full text screening. Nine reports of seven distinct studies were included; four were randomized trials, one was a cohort design and three were descriptive studies. Six studies were rated as methodologically weak, and one was rated as moderate. Studies were not meta-analyzed because of heterogeneity, low methodological quality, and incomplete data reporting. No beneficial dissemination strategies were found except one that looks promising, the use of peer educators in the worksite, which led to a short-term increase in fruit and vegetable intake. Conclusions and Implications Overall, the quality of the evidence is not strong and is primarily descriptive rather than evaluative. No clear conclusions can be drawn from these data. Controlled studies are needed to evaluate dissemination strategies, and to compare dissemination and diffusion strategies with different messages and different target audiences.

  17. Global Diffusion Pattern and Hot SPOT Analysis of Vaccine-Preventable Diseases

    Science.gov (United States)

    Jiang, Y.; Fan, F.; Zanoni, I. Holly; Li, Y.

    2017-10-01

    Spatial characteristics reveal the concentration of vaccine-preventable disease in Africa and the Near East and that disease dispersion is variable depending on disease. The exception is whooping cough, which has a highly variable center of concentration from year to year. Measles exhibited the only statistically significant spatial autocorrelation among all the diseases under investigation. Hottest spots of measles are in Africa and coldest spots are in United States, warm spots are in Near East and cool spots are in Western Europe. Finally, cases of measles could not be explained by the independent variables, including Gini index, health expenditure, or rate of immunization. Since the literature confirms that each of the selected variables is considered determinants of disease dissemination, it is anticipated that the global dataset of disease cases was influenced by reporting bias.

  18. GHK-Cu may Prevent Oxidative Stress in Skin by Regulating Copper and Modifying Expression of Numerous Antioxidant Genes

    Directory of Open Access Journals (Sweden)

    Loren Pickart

    2015-07-01

    Full Text Available The copper binding tripeptide GHK (glycyl-l-histidyl-l-lysine is a naturally occurring plasma peptide that significantly declines during human aging. It has been established that GHK:Copper(2+ improves wound healing and tissue regeneration and stimulates collagen and decorin production. GHK-Cu also supports angiogenesis and nerve outgrowth, improves the condition of aging skin and hair, and possesses antioxidant and anti-inflammatory effects. In addition, it increases cellular stemness and secretion of trophic factors by mesenchymal stem cells. GHK’s antioxidant actions have been demonstrated in vitro and in animal studies. They include blocking the formation of reactive oxygen and carbonyl species, detoxifying toxic products of lipid peroxidation such as acrolein, protecting keratinocytes from lethal Ultraviolet B (UVB radiation, and blocking hepatic damage by dichloromethane radicals. In recent studies, GHK has been found to switch gene expression from a diseased state to a healthier state for certain cancers and for chronic obstructive pulmonary disease (COPD. The Broad Institute’s Connectivity Map indicated that GHK induces a 50% or greater change of expression in 31.2% of human genes. This paper reviews biological data demonstrating positive effects of GHK in skin and proposes interaction with antioxidant-related genes as a possible explanation of its antioxidant activity.

  19. Copper transport.

    Science.gov (United States)

    Linder, M C; Wooten, L; Cerveza, P; Cotton, S; Shulze, R; Lomeli, N

    1998-05-01

    In adult humans, the net absorption of dietary copper is approximately 1 mg/d. Dietary copper joins some 4-5 mg of endogenous copper flowing into the gastrointestinal tract through various digestive juices. Most of this copper returns to the circulation and to the tissues (including liver) that formed them. Much lower amounts of copper flow into and out of other major parts of the body (including heart, skeletal muscle, and brain). Newly absorbed copper is transported to body tissues in two phases, borne primarily by plasma protein carriers (albumin, transcuprein, and ceruloplasmin). In the first phase, copper goes from the intestine to the liver and kidney; in the second phase, copper usually goes from the liver (and perhaps also the kidney) to other organs. Ceruloplasmin plays a role in this second phase. Alternatively, liver copper can also exit via the bile, and in a form that is less easily reabsorbed. Copper is also present in and transported by other body fluids, including those bathing the brain and central nervous system and surrounding the fetus in the amniotic sac. Ceruloplasmin is present in these fluids and may also be involved in copper transport there. The concentrations of copper and ceruloplasmin in milk vary with lactational stage. Parallel changes occur in ceruloplasmin messenger RNA expression in the mammary gland (as determined in pigs). Copper in milk ceruloplasmin appears to be particularly available for absorption, at least in rats.

  20. Grape seed and skin extract alleviates high-fat diet-induced renal lipotoxicity and prevents copper depletion in rat.

    Science.gov (United States)

    Charradi, Kamel; Elkahoui, Salem; Karkouch, Ines; Limam, Ferid; Hamdaoui, Ghaith; Ben Hassine, Fethy; El May, Michèle Veronique; El May, Ahmed; Aouani, Ezzedine

    2013-03-01

    Obesity is a public health problem that contributes to morbidity and mortality from diabetes, heart disease, stroke, and cancers. The purpose of this investigation was to analyse the link between obesity-induced oxidative stress, renal steatosis, and kidney dysfunction, as well as the protective effect of grape seed and skin extract. Rats were fed a standard diet or a high-fat diet for 6 weeks and were either treated or not treated with grape seed and skin extract. Fat-induced oxidative stress was evaluated in the kidney with a special emphasis on transition metals. High-fat diet induced triglyceride deposition and disturbances in kidney function parameters, which are linked to an oxidative stress status and depletion of copper from the kidney. Grape seed and skin extract abrogated almost all fat-induced kidney disturbances. Grape seed and skin extract exerted potential protection against fat-induced kidney lipotoxicity and should find potential application in other kidney-related diseases.

  1. Diffusion-controlled intergranular penetration and embrittlement of copper by liquid bismuth between 300 and 600 Celsius degrees; Penetration intergranulaire fragilisante du cuivre par le bismuth liquide: identification de la cinetique et du mecanisme de type diffusionnel entre 300 et 600 deg

    Energy Technology Data Exchange (ETDEWEB)

    Laporte, V

    2005-02-15

    Hybrid reactors are a new concept for energy production and nuclear waste treatment. Among other requirements, structural materials have to withstand liquid metal embrittlement. This thesis aimed therefore to identify the controlling mechanism for the intergranular embrittlement of copper in contact with liquid bismuth. Scanning electron microscopy, Auger electron spectroscopy, X-ray photoelectron spectroscopy and Rutherford backscattering spectroscopy have been used to analyze fracture surfaces of both copper polycrystals and a copper bicrystal (symmetric tilt boundary 50 degrees <100>). These analyses reveal both parabolic intergranular penetration kinetics and a maximal intergranular bismuth concentration that is less than two monolayers equivalent. These two results allow us to identify grain boundary diffusion as the controlling mechanism for the intergranular penetration of copper by liquid bismuth between 300 and 600 Celsius degrees, showing the absence of perfect grain boundary wetting. (author)

  2. Pitting corrosion of copper. An equilibrium - mass transport study

    Energy Technology Data Exchange (ETDEWEB)

    Taxen, C. [Swedish Corrosion Inst., Stockholm (Sweden)

    2002-08-01

    A mathematical model for the propagation of corrosion pits is described and used to calculate the potentials below which copper is immune to pitting. The model uses equilibrium data and diffusion coefficients and calculates the stationary concentration profiles of 26 aqueous species from the bulk water outside a corrosion pit to the site of the metal dissolution. Precipitation of oxides and salts of copper is considered. Studied conditions include water compositions from tap waters to seawater at the temperatures 25 deg C and 75 deg C. Carbonate and sulphate are aggressive towards copper because of complex formation with divalent copper. Carbonate is less aggressive in a corrosion pit than outside at the pH of the bulk. Carbonate carries acidity out from the pit, favours oxide formation and may prevent the initiation of acidic corrosion pits. The concentration profiles are used to estimate the maximum propagation rates for a corrosion pit. A high potential is found to be the most important factor for the rate of propagation. The levels of potential copper can sustain, as corrosion potentials are discussed in terms of the stability of cuprous oxide as a cathode material for oxygen reduction relative to non-conducting cupric phases.

  3. Oral administration of copper to rats leads to increased lymphocyte cellular DNA degradation by dietary polyphenols: implications for a cancer preventive mechanism.

    Science.gov (United States)

    Khan, Husain Y; Zubair, Haseeb; Ullah, Mohd F; Ahmad, Aamir; Hadi, Sheikh M

    2011-12-01

    To account for the observed anticancer properties of plant polyphenols, we have earlier proposed a mechanism which involves the mobilization of endogenous copper ions by polyphenols leading to the generation of reactive oxygen species (ROS) that serve as proximal DNA cleaving agents and lead to cell death. Over the last decade we have proceeded to validate our hypothesis with considerable success. As a further confirmation of our hypothesis, in this paper we first show that oral administration of copper to rats leads to elevated copper levels in lymphocytes. When such lymphocytes with a copper overload were isolated and treated with polyphenols EGCG, genistein and resveratrol, an increased level of DNA breakage was observed. Further, preincubation of lymphocytes having elevated copper levels with the membrane permeable copper chelator neocuproine, resulted in inhibition of polyphenol induced DNA degradation. However, membrane impermeable chelator of copper bathocuproine, as well as iron and zinc chelators were ineffective in causing such inhibition in DNA breakage, confirming the involvement of endogenous copper in polyphenol induced cellular DNA degradation. It is well established that serum and tissue concentrations of copper are greatly increased in various malignancies. In view of this fact, the present results further confirm our earlier findings and strengthen our hypothesis that an important anticancer mechanism of plant polyphenols could be the mobilization of intracellular copper leading to ROS-mediated cellular DNA breakage. In this context, it may be noted that cancer cells are under considerable oxidative stress and increasing such stress to cytotoxic levels could be a successful anticancer approach.

  4. Copper hypersensitivity

    DEFF Research Database (Denmark)

    Fage, Simon W; Faurschou, Annesofie; Thyssen, Jacob P

    2014-01-01

    . As a metal, it possesses many of the same qualities as nickel, which is a known strong sensitizer. Cumulative data on subjects with presumed related symptoms and/or suspected exposure showed that a weighted average of 3.8% had a positive patch test reaction to copper. We conclude that copper is a very weak...... hypersensitivity, a database search of PubMed was performed with the following terms: copper, dermatitis, allergic contact dermatitis, contact hypersensitivity, contact sensitization, contact allergy, patch test, dental, IUD, epidemiology, clinical, and experimental. Human exposure to copper is relatively common...

  5. On the use of (3-trimethoxysilylpropyl)diethylenetriamine self-assembled monolayers as seed layers for the growth of Mn based copper diffusion barrier layers

    Science.gov (United States)

    Brady-Boyd, A.; O'Connor, R.; Armini, S.; Selvaraju, V.; Hughes, G.; Bogan, J.

    2018-01-01

    In this work x-ray photoelectron spectroscopy is used to investigate in-vacuo, the interaction of metallic manganese with a (3-trimethoxysilylpropyl)diethylenetriamine (DETA) self-assembled monolayer (SAM) on SiO2 and non-porous low-k dielectric materials. Subsequent deposition of a ∼0.5 nm thick Mn, followed by a 200 °C anneal results in the Mn diffusing through the SAM to interact with the underlying SiO2 layer to form a Mn-silicate layer. Furthermore, there is evidence that the Mn interacts with the carbon and nitrogen within the SAM to form Mn-carbide and Mn-nitride, respectively. When deposited on low-k materials the Mn is found to diffuse through to the SAM on deposition and interact both with the SAM and the underlying substrate in a similar fashion.

  6. Solid state bonding of beryllium-copper for an ITER first wall application

    International Nuclear Information System (INIS)

    Odegard, B.C. Jr.; Cadden, C.H.

    1998-02-01

    Several different joint assemblies were evaluated in support of a manufacturing technology for diffusion bonding a beryllium armor tile to a copper alloy heat sink for fusion reactor applications. Because beryllium reacts with all but a few elements to form intermetallic compounds, this study considered several different surface treatments as a means of both inhibiting these reactions and promoting a good diffusion bond between the two substrates. A diffusion bonded assemblies used aluminum or an aluminum-beryllium composite (AlBeMet-150) as the interfacial material in contact with beryllium. In most cases, explosive bonding was utilized as a technique for joining the copper alloy heat sink to an aluminum or AlBeMet-150 substrate, which was subsequently diffusion bonded to an aluminum coated beryllium tile. In this approach, a 250 microm thick titanium foil was used as a diffusion barrier between the copper and aluminum to prevent the formation of Cu-Al intermetallic phases. In all cases, a hot isostatic pressing (HIP) furnace was used in conjunction with canned assemblies in order to minimize oxidation and apply sufficient pressure on the assembly for excellent metal-to-metal contact and subsequent bonding. Several different processing schedules were evaluated during the course of this study; bonded assemblies were produced that failed outside the bond area indicating a 100% joint efficiency

  7. Solid state bonding of beryllium-copper for an ITER first wall application

    Energy Technology Data Exchange (ETDEWEB)

    Odegard, B.C. Jr.; Cadden, C.H. [Sandia National Labs., Livermore, CA (United States)

    1998-01-01

    Several different joint assemblies were evaluated in support of a manufacturing technology for diffusion bonding a beryllium armor tile to a copper alloy heat sink for fusion reactor applications. Because beryllium reacts with all but a few elements to form intermetallic compounds, this study considered several different surface treatments as a means of both inhibiting these reactions and promoting a good diffusion bond between the two substrates. All diffusion bonded assemblies used aluminum or an aluminum-beryllium composite (AlBeMet-150) as the interfacial material in contact with beryllium. In most cases, explosive bonding was utilized as a technique for joining the copper alloy heat sink to an aluminum or AlBeMet-150 substrate, which was subsequently diffusion bonded to an aluminum coated beryllium tile. In this approach, a 250 {mu}m thick titanium foil was used as a diffusion barrier between the copper and aluminum to prevent the formation of Cu-Al intermetallic phases. In all cases, a hot isostatic pressing (HIP) furnace was used in conjunction with canned assemblies in order to minimize oxidation and apply sufficient pressure on the assembly for excellent metal-to-metal contact and subsequent bonding. Several different processing schedules were evaluated during the course of this study; bonded assemblies were produced that failed outside the bond area indicating a 100% joint efficiency. (author)

  8. Copper (II)

    African Journals Online (AJOL)

    CLEMENT O BEWAJI

    ABSTRACT: A Schiff base was prepared from the reaction of 2 - amino - 3 – methylbutanoic acid and 2, 4 - pentanedione. The reaction of the prepared Schiff base with ethanolic solution of copper (II) chloride formed diaquo bis( N – 2 – amino – 3 - methylbutyl - 2, 4 - pentanedionato) copper (II) complex. The Schiff base is ...

  9. Structural and magnetic studies on copper succinate dihydrate ...

    Indian Academy of Sciences (India)

    M P BINITHA

    2017-08-21

    Aug 21, 2017 ... Abstract. Single crystals of copper succinate dihydrate were grown in silica gel by slow diffusion of copper chloride to sodium metasilicate gel impregnated with succinic acid. The grown crystal was subjected to single crystal X-ray diffraction studies. In its structure each copper atom is penta co-ordinated to ...

  10. Potentiating effect of ecofriendly synthesis of copper oxide ...

    Indian Academy of Sciences (India)

    This study reports the in vitro antimicrobial and anticancer activities of biologically synthesized copper nanoparticles. The antimicrobial activity of green synthesized copper oxide nanoparticles was assessed by well diffusion method. The anticancer activity of brown algae-mediated copper oxide nanoparticles was ...

  11. Copper diffusion in In2S3 and charge separation at In2S3/CuSCN and TiO2/In2S3 interfaces

    International Nuclear Information System (INIS)

    Juma, Albert Owino

    2013-01-01

    The concept of inorganic nanostructured solar cells consists of a very thin absorber layer sandwiched between highly structured electron and hole conductors. When a TiO 2 /In 2 S 3 /CuSCN nanocomposite heterostructure is illuminated with light, photo-generated electrons in In 2 S 3 can be injected into the conduction band of TiO 2 and holes into the valence band of CuSCN. Charge transfer at the interfaces is limited by the deposition parameters, band alignment and diffusion of Cu from CuSCN into In 2 S 3 , which was the focus of this work. TiO 2 nanoparticles were screen printed onto SnO 2 :F (FTO)-coated glass substrates to give a layer of nanoporous (np) TiO 2 . In 2 S 3 layers were deposited by thermal evaporation or ion layer gas reaction (ILGAR) methods producing Cl-free (In(acac) 3 precursor) and Cl-containing (InCl 3 precursor) layers. A spray-spin method was developed for deposition of CuSCN onto In 2 S 3 . Diffusion of Cu into In 2 S 3 layers was investigated by Rutherford backscattering spectrometry (RBS) while charge transport mechanisms were studied with surface photovoltage (SPV) technique in the fixed capacitor configuration. The activation energy (Ea) for Cu diffusion in thermally evaporated and Cl-free ILGAR In 2 S 3 layers was 0.30 and 0.24 eV, respectively but increased to between 0.72 and 0.78 eV for Cl-containing In 2 S 3 with residual Cl concentrations of 7.8 - 13.8 at.%. The diffusion prefactor (D 0 ) was six orders of magnitude higher for Cl-containing compared to Cl-free layers. The relationship between E a and D 0 was described by the Meyer-Neldel rule with a Meyer-Neldel energy of 40 meV. The presence of Cl has no significant influence on the structural properties of In 2 S 3 but resulted in a modified diffusion mechanism for Cu diffusion. The photovoltage of In 2 S 3 /CuSCN samples decreased after annealing for longer than 2 min at 200 C. A defect band was formed near the interface where holes accumulated and electrons tunneled through

  12. Non-local interaction via diffusible resource prevents coexistence of cooperators and cheaters in a lattice model.

    Directory of Open Access Journals (Sweden)

    David Bruce Borenstein

    Full Text Available Many cellular populations cooperate through the secretion of diffusible extracellular resources, such as digestive enzymes or virulence factors. Diffusion of these resources leads to long-range intercellular interactions, creating the possibility of cooperation but also the risk of exploitation by non-producing neighbors. In the past, considerable attention has been given to game-theoretic lattice models of intercellular cooperation. In these models, coexistence is commonly observed between cooperators (corresponding to resource producers and cheaters (corresponding to nonproducers. However, these models consider only interactions between direct competitors. We find that when individuals are allowed to interact non-locally through the diffusion of a shared resource coexistence between cooperators and cheaters is lost. Instead, we find population dynamics similar to simple competition, either neutral or biased, with no balancing selection that would favor coexistence. Our results highlight the importance of an accurate treatment of diffusion of shared resources and argue against the generality of the conclusions of game-theoretic lattice models.

  13. Simultaneous Enrichment and On-line Detection of Low-Concentration Copper, Cobalt, and Nickel Ions in Water by Near-Infrared Diffuse Reflectance Spectroscopy Combined with Chemometrics.

    Science.gov (United States)

    Iqbal, Jibran; Du, Yiping; Howari, Fares; Bataineh, Mahmoud; Muhammad, Nawshad; Rahim, Abdur

    2017-03-01

    Sensitive detection of heavy metal ions in water is of great importance considering the effects that heavy metals have on public health. A developed fluidized bed enrichment technique was used to concentrate and detect low concentrations of Cu2+, Co2+, and Ni2+ in water samples by near-IR diffuse reflectance (NIDR) spectroscopy (NIDRS) directly without using any chemicals or reagents. The NIDR spectra of adsorbent were measured on-line, and quantitative detection was achieved by applying a built partial least-squares chemometric model. Sensitivity and accuracy was improved significantly because large-volume mixture solutions were used in the enrichment process. Root mean square error of cross-validation values for Cu2+, Co2+, and Ni2+ were 0.29, 0.41, and 0.35 μg/mL, respectively, with mean relative error values in the acceptable range of 6.56-10.27%. This study confirms the potential application of fluidized bed enrichment combined with NIDRS and chemometrics for the simultaneous detection of trace heavy metal ions in water, with low relative error.

  14. Diffusion and adhesion properties of Cu films on polyimide substrates

    International Nuclear Information System (INIS)

    Liang, T.X.; Liu, Y.Q.; Fu, Z.Q.; Luo, T.Y.; Zhang, K.Y.

    2005-01-01

    Copper thin films were prepared on polyimide (PI) substrates by physical vapor deposition (PVD) and chemical vapor deposition (CVD). Titanium nitride (TiN) diffusion barrier layers were deposited between the copper films and the PI substrates by PVD. Auger electron spectroscopy compositional depth profile showed that TiN barrier layer was very effective in preventing copper diffusion into PI substrate even after the Cu/TiN/PI samples were annealed at 300 deg. C for 5 h. For the as-deposited CVD-Cu/PI, CVD-Cu/TiN/PI, and as-deposited PVD-Cu/PI samples, the residual stress in Cu films was very small. Relatively larger residual stress existed in Cu films for PVD-Cu/TiN/PI samples. For PVD-Cu/TiN/PI samples, annealing can increase the peeling strength to the level observed without a diffusion barrier. The adhesion improvement of Cu films by annealing treatment can be attributed to lowering of the residual tensile stress in Cu films

  15. Prevention

    Science.gov (United States)

    ... Error processing SSI file About Heart Disease & Stroke Prevention Heart disease and stroke are an epidemic in ... secondhand smoke. Barriers to Effective Heart Disease & Stroke Prevention Many people with key risk factors for heart ...

  16. Laboratory evaluation of borate:amine:copper derivatives In wood for fungal decay protection

    Science.gov (United States)

    George Chen

    2011-01-01

    This study aimed to evaluate borate:amine:copper derivatives in wood for fungal decay protection as well as the permanence of copper and boron in wood. Each of four derivatives of borate:amine:copper prevented fungal decay in wood. Disodium tetraborate decahydrate (borax):amine:copper derivatives with 0.61-0.63% retention after water leaching prevented decay by...

  17. Experience and lessons from health impact assessment guiding prevention and control of HIV/AIDS in a copper mine project, northwestern Zambia.

    Science.gov (United States)

    Knoblauch, Astrid M; Divall, Mark J; Owuor, Milka; Nduna, Kennedy; Ng'uni, Harrison; Musunka, Gertrude; Pascall, Anna; Utzinger, Jürg; Winkler, Mirko S

    2017-07-04

    To avoid or mitigate potential project-related adverse health effects, the Trident copper project in Kalumbila, northwestern Zambia, commissioned a health impact assessment. HIV was identified a priority health issue based on the local vulnerability to HIV transmission and experience from other mining projects in Africa. Hence, an HIV/AIDS management plan was developed, including community and workplace interventions, with HIV testing and counselling (HTC) being one of the key components. We present trends in HTC data over a 4-year period. In 13 communities affected by the Trident project, HTC was implemented from 2012 onwards, using rapid diagnostic tests, accompanied by pre- and post-test counselling through trained personnel. In addition, HTC was initiated in the project workforce in 2013, coinciding with the launch of the mine development. HTC uptake and HIV positivity rates were assessed in the study population and linked to demographic factors using regression analysis. In total, 11,638 community members and 5564 workers have taken up HTC with an increase over time. The HIV positivity rate in the community was 3.0% in 2012 and 3.4% in 2015, while positivity rate in the workforce was 5.2% in 2013 and 4.3% in 2015. Females showed a significantly higher odds of having a positive test result than males (odds ratio (OR) = 1.96, 95% confidence interval (CI): 1.55-2.50 among women in the community and OR = 2.90, 95% CI: 1.74-4.84 among women in the workforce). HTC users in the 35-49 years age group were most affected by HIV, with an average positivity rate of 6.6% in the community sample and 7.9% in the workforce sample. These study groups had 4.50 and 4.95 higher odds of being positive, respectively, compared to their younger counterparts (15-24 years). While HTC uptake increased five-fold in the community and almost three-fold in the workplace, the HIV positivity rates were insignificantly higher in 2015 compared to 2012. Our data can be used alongside other

  18. Brazing copper to dispersion-strengthened copper

    Energy Technology Data Exchange (ETDEWEB)

    Ryding, D.G.; Allen, D.; Lee, R.

    1996-08-01

    The Advanced Photon Source (APS) is a state-of-the-art synchrotron light source that will produce intense x-ray beams, which will allow the study of smaller samples and faster reactions and processes at a greater level of detail that has been possible to date. The beam is produced by using third-generation insertion devices in a 7 GeV electron/positron storage ring that is 1100 meters in circumference. The heat load from these intense high power devices is very high and certain components must sustain total heat loads of 3 to 15 kW and heat fluxes of 30 W/mm{sup 2}. Because the beams will cycle on and off many times, thermal shock and fatigue will be a problem. High heat flux impinging on a small area causes a large thermal gradient that results in high stress. GlidCop{reg_sign}, a dispersion strengthened copper, is the desired material because of its high thermal conductivity and superior mechanical properties as compared to copper and its alloys. GlidCop is not amenable to joining by fusion welding, and brazing requires diligence because of high diffusivity. Brazing procedures were developed using optical and scanning electron microscopy.

  19. Prevention

    Science.gov (United States)

    ... Contact Aging & Health A to Z Find a Geriatrics Healthcare Professional Medications & Older Adults Making Your Wishes ... Prevention Hearing Loss Heart Attack High Blood Pressure Nutrition Osteoporosis Shingles Skin Cancer Related News Quitting Smoking, ...

  20. Copper Affects the Location of Zinc in Bimetallic Ion-Exchanged Mordenite.

    Science.gov (United States)

    Reule, Allen A C; Shen, Jing; Semagina, Natalia

    2018-03-25

    Bimetallic ion exchange on a zeolite often impacts its catalytic properties compared to its monometallic counterparts. Here, we address the synergistic effect of simultaneous copper and zinc ion exchange on mordenite (MOR), as found earlier for dimethyl ether (DME) carbonylation. Samples with various Cu/Zn ratios were characterized by diffuse-reflectance infrared Fourier-transform spectroscopy (DRIFTS) in the 3600 and 720 cm -1 regions, pore distribution analysis through Ar physisorption, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), and transmission electron microscopy (TEM). When ion-exchanged alone, copper preferentially occupies 12-membered rings, whereas zinc occupies 8-membered rings. In bimetallic combinations, the zinc addition was found to prevent the copper from sintering into nanoparticles and to increase its coordination strength to the zeolite. At a Cu/Zn ratio of 0.25 (for MOR with Si/Al=6.5), copper promotes zinc ion exchange into 12-membered rings, more specifically, into T4 sites that are known for the formation of the coke precursor in DME carbonylation on a MOR. The sites became blocked during the bimetallic ion exchange, leading to suppressed catalyst deactivation. The study contributes to the understanding of mutual ion effects in bimetallic exchanged zeolites and highlights the major role of copper as a governing factor in determining the location of co-exchanged zinc on a MOR. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Improving survival and preventing recurrence of diffuse large B-cell lymphoma in younger patients: current strategies and future directions

    Directory of Open Access Journals (Sweden)

    Karlin L

    2013-03-01

    Full Text Available Lionel Karlin, Bertrand CoiffierHematology Department, Centre Hospitalier Lyon Sud, Pierre-Benite, FranceAbstract: Prognosis of diffuse large B-cell lymphoma (DLBCL has considerably improved during the last decade, mainly due to the addition of rituximab to chemotherapy. However, a significant proportion of patients still experience primary refractory disease or short-term relapses, conferring poor survival. Thus, achieving first-line complete remission is of major importance, especially in young and fit patients. Current strategies are based on the age-adapted International Prognostic Index, which separates patients into three prognostic subgroups (low-risk, intermediate-risk, and high-risk. However, it is based only on clinical variables, and we have learned from daily practice that there remains a marked heterogeneity within each subgroup. Recently, biological prognostic factors have emerged, and should now be part of initial evaluation to guide treatment. Among those, so-called double-hit DLBCL with deregulation of both MYC and BCL2 genes usually follows a particularly aggressive course and should be treated more intensively. But for many other patients, the indication of high-dose therapy rather than immunochemotherapy alone remains controversial. In these cases, the interest of an early 18F fluoro-2-deoxy-d-glucose positron emission tomography evaluation-based strategy is now being assessed in ongoing clinical trials. Moreover, other strategies to improve response and survival consist in adding novel agents to standard chemotherapy. In this field, newly developed anti-CD20 monoclonal antibodies and immunomodulatory drugs could be of particular interest during induction therapy to optimize the quality of response, but also in maintenance treatment, in order to decrease the risk of relapse. Only well-conducted clinical trials will be able to resolve all these issues. Therefore, physicians should be encouraged, as far as possible, to propose

  2. Ultralow-loss CMOS copper plasmonic waveguides

    DEFF Research Database (Denmark)

    Fedyanin, Dmitry Yu.; Yakubovsky, Dmitry I.; Kirtaev, Roman V.

    2016-01-01

    with microelectronics manufacturing technologies. This prevents plasmonic components from integration with both silicon photonics and silicon microelectronics. Here, we demonstrate ultralow-loss copper plasmonic waveguides fabricated in a simple complementary metal-oxide semiconductor (CMOS) compatible process, which...

  3. Prevention

    DEFF Research Database (Denmark)

    Halken, S; Høst, A

    2001-01-01

    , breastfeeding should be encouraged for 4-6 months. In high-risk infants a documented extensively hydrolysed formula is recommended if exclusive breastfeeding is not possible for the first 4 months of life. There is no evidence for preventive dietary intervention neither during pregnancy nor lactation...... populations. These theories remain to be documented in proper, controlled and prospective studies. Breastfeeding and the late introduction of solid foods (>4 months) is associated with a reduced risk of food allergy, atopic dermatitis, and recurrent wheezing and asthma in early childhood. In all infants....... Preventive dietary restrictions after the age of 4-6 months are not scientifically documented....

  4. Comparative genomic analyses of copper transporters and cuproproteomes reveal evolutionary dynamics of copper utilization and its link to oxygen.

    Directory of Open Access Journals (Sweden)

    Perry G Ridge

    2008-01-01

    Full Text Available Copper is an essential trace element in many organisms and is utilized in all domains of life. It is often used as a cofactor of redox proteins, but is also a toxic metal ion. Intracellular copper must be carefully handled to prevent the formation of reactive oxygen species which pose a threat to DNA, lipids, and proteins. In this work, we examined patterns of copper utilization in prokaryotes by analyzing the occurrence of copper transporters and copper-containing proteins. Many organisms, including those that lack copper-dependent proteins, had copper exporters, likely to protect against copper ions that inadvertently enter the cell. We found that copper use is widespread among prokaryotes, but also identified several phyla that lack cuproproteins. This is in contrast to the use of other trace elements, such as selenium, which shows more scattered and reduced usage, yet larger selenoproteomes. Copper transporters had different patterns of occurrence than cuproproteins, suggesting that the pathways of copper utilization and copper detoxification are independent of each other. We present evidence that organisms living in oxygen-rich environments utilize copper, whereas the majority of anaerobic organisms do not. In addition, among copper users, cuproproteomes of aerobic organisms were larger than those of anaerobic organisms. Prokaryotic cuproproteomes were small and dominated by a single protein, cytochrome c oxidase. The data are consistent with the idea that proteins evolved to utilize copper following the oxygenation of the Earth.

  5. Vectorization of copper complexes via biocompatible and biodegradable PLGA nanoparticles

    International Nuclear Information System (INIS)

    Courant, T; Roullin, V G; Andry, M C; Cadiou, C; Chuburu, F; Delavoie, F; Molinari, M; Gafa, V

    2010-01-01

    A double emulsion-solvent diffusion approach with fully biocompatible materials was used to encapsulate copper complexes within biodegradable nanoparticles, for which the release kinetics profiles have highlighted their potential use for a prolonged circulating administration.

  6. Chemistry of the copper silicon interface

    International Nuclear Information System (INIS)

    Ford, M.J.; Sashin, V.A.; Nixon, K.

    2002-01-01

    Full text: Copper and silicon readily interdiffuse, even at room temperature, to form an interface which can be several nanometers thick. Over the years considerable effort has gone into investigating the diffusion process and chemical nature of the interface formed. Photoemission measurements give evidence for the formation of a stable suicide with a definite stoichiometry, Cu 3 Si. This is evidenced by splitting of the Si LVV Auger line and slight shifts and change in shape of the copper valence band density of states as measured by ultra-violet photoemission. In this paper we present calculations of the electronic structure of copper suicide, bulk copper and silicon, and preliminary measurements of the interface by electron momentum spectroscopy. Densities of states for copper and copper suicide are dominated by the copper 3d bands, and difference between the two compounds are relatively small. By contrast, the full band structures are quite distinct. Hence, experimental measurements of the full band structure of the copper on silicon interface, for example by EMS, have the potential to reveal the chemistry of the interface in a detailed way

  7. Case of sensory ataxic ganglionopathy-myelopathy in copper deficiency.

    Science.gov (United States)

    Zara, Gabriella; Grassivaro, Francesca; Brocadello, Filippo; Manara, Renzo; Pesenti, Francesco Francini

    2009-02-15

    Spinal cord involvement associated with severe copper deficiency has been reported in the last 8 years. Copper deficiency may produce an ataxic myelopathy. Clinical and neuroimaging findings are similar to the subacute combined degeneration seen in patients with vitamin B12 deficiency. Macrocytic, normocytic and microcytic anemia, leukopenia and, in severe cases, pancytopenia are well known hematologic manifestations. The most patients with copper deficiency myelopathy had unrecognized carency. Some authors suggested that early recognition and copper supplementation may prevent neurologic deterioration but clinical findings do not improve. We present a patient with copper deficiency, dorsal root ganglions and cervical dorsal columns involvement. Clinical status and neuroimaging improved after copper replacement therapy. Sensory neurons of dorsal root ganglia may be the most sensitive nervous pathway. In this case the early copper treatment allowed to improve neurologic lesions and to prevent further involvements.

  8. Copper-induced tight junction mRNA expression changes, apoptosis and antioxidant responses via NF-κB, TOR and Nrf2 signaling molecules in the gills of fish: Preventive role of arginine

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Biao [Animal Nutrition Institute, Sichuan Agricultural University, Chengdu 611130, Sichuan (China); Feng, Lin; Jiang, Wei-Dan [Animal Nutrition Institute, Sichuan Agricultural University, Chengdu 611130, Sichuan (China); Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, Sichuan (China); Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu 611130, Sichuan (China); Wu, Pei [Animal Nutrition Institute, Sichuan Agricultural University, Chengdu 611130, Sichuan (China); Kuang, Sheng-Yao [Animal Nutrition Institute, Sichuan Academy of Animal Science, Chengdu, 610066, Sichuan (China); Jiang, Jun [Animal Nutrition Institute, Sichuan Agricultural University, Chengdu 611130, Sichuan (China); Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, Sichuan (China); Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu 611130, Sichuan (China); Tang, Ling; Tang, Wu-Neng [Animal Nutrition Institute, Sichuan Academy of Animal Science, Chengdu, 610066, Sichuan (China); Zhang, Yong-An [Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China); Liu, Yang, E-mail: kyckgk@hotmail.com [Animal Nutrition Institute, Sichuan Agricultural University, Chengdu 611130, Sichuan (China); Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, Sichuan (China); Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu 611130, Sichuan (China); and others

    2015-01-15

    Highlights: • Cu exposure induced oxidative stress via disruption of antioxidant system. • Cu exposure disrupted TJ mRNA expression through regulation of cytokines in fish. • Cu induced gill apoptosis partly via intrinsic pathway but not extrinsic pathway. • Cu exposure can regulate Nrf2, NF-κB and TOR signaling molecules in fish. • Arginine can effectively prevent Cu-induced fish gill damage. - Abstract: This study explored the possible preventive effects of dietary arginine on copper (Cu)-induced tight junction mRNA expression changes, apoptosis and antioxidant responses in the gills of young grass carp (Ctenopharyngodon idella). The results indicated that exposure to 0.7 mg/L (11.01 μmol/L) Cu for 96 h induced the production of reactive oxygen species (ROS), thereby increasing protein oxidation, lipid peroxidation and DNA damage in the gills of fish. However, these oxidative effects were prevented by arginine supplementation. Arginine also prevented the toxic effects of Cu on the activities of copper/zinc superoxide dismutase (SOD1), glutathione-S-transferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR) and the glutathione (GSH) content (P < 0.05). However, Cu induced an adaptive increase in the activity of catalase (CAT), and arginine supplementation further increased CAT activity (P < 0.05). Moreover, Cu induced increases in the relative mRNA expressions of SOD1, CAT, GPx, GST, caspase-3, caspase-9, NF-E2-related factor 2 (Nrf2), Kelch-like-ECH-associated protein 1a (Keap1a), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-8 (IL-8), transforming growth factor-β (TGF-β) and nuclear transcription factor-κB p65 (NF-κB p65) in the gills of grass carp (P < 0.05). In contrast, the relative mRNA expression levels of occludin, zonula occludens-1 (ZO-1), claudin b, claudin 3, claudin 12, target of rapamycin (TOR) and inhibitor factor κBα (IκBα) in the gills were decreased by Cu (P < 0.05). However, pre

  9. Copper-induced tight junction mRNA expression changes, apoptosis and antioxidant responses via NF-κB, TOR and Nrf2 signaling molecules in the gills of fish: Preventive role of arginine

    International Nuclear Information System (INIS)

    Wang, Biao; Feng, Lin; Jiang, Wei-Dan; Wu, Pei; Kuang, Sheng-Yao; Jiang, Jun; Tang, Ling; Tang, Wu-Neng; Zhang, Yong-An; Liu, Yang

    2015-01-01

    Highlights: • Cu exposure induced oxidative stress via disruption of antioxidant system. • Cu exposure disrupted TJ mRNA expression through regulation of cytokines in fish. • Cu induced gill apoptosis partly via intrinsic pathway but not extrinsic pathway. • Cu exposure can regulate Nrf2, NF-κB and TOR signaling molecules in fish. • Arginine can effectively prevent Cu-induced fish gill damage. - Abstract: This study explored the possible preventive effects of dietary arginine on copper (Cu)-induced tight junction mRNA expression changes, apoptosis and antioxidant responses in the gills of young grass carp (Ctenopharyngodon idella). The results indicated that exposure to 0.7 mg/L (11.01 μmol/L) Cu for 96 h induced the production of reactive oxygen species (ROS), thereby increasing protein oxidation, lipid peroxidation and DNA damage in the gills of fish. However, these oxidative effects were prevented by arginine supplementation. Arginine also prevented the toxic effects of Cu on the activities of copper/zinc superoxide dismutase (SOD1), glutathione-S-transferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR) and the glutathione (GSH) content (P < 0.05). However, Cu induced an adaptive increase in the activity of catalase (CAT), and arginine supplementation further increased CAT activity (P < 0.05). Moreover, Cu induced increases in the relative mRNA expressions of SOD1, CAT, GPx, GST, caspase-3, caspase-9, NF-E2-related factor 2 (Nrf2), Kelch-like-ECH-associated protein 1a (Keap1a), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-8 (IL-8), transforming growth factor-β (TGF-β) and nuclear transcription factor-κB p65 (NF-κB p65) in the gills of grass carp (P < 0.05). In contrast, the relative mRNA expression levels of occludin, zonula occludens-1 (ZO-1), claudin b, claudin 3, claudin 12, target of rapamycin (TOR) and inhibitor factor κBα (IκBα) in the gills were decreased by Cu (P < 0.05). However, pre

  10. Separation of copper-64 from copper phthalocyanine

    International Nuclear Information System (INIS)

    Battaglin, R.I.M.

    1979-01-01

    The separation of copper-64 from irradiated copper phthalocyanine by Szilard-Chalmers effect is studied. Two methods of separation are used: one of them is based on the dissolution of the irradiated dry compound in concentrated sulfuric acid following its precipitation in water. In the other one the compound is irradiated with water in paste form following treatment with water and hydrochloric acid. The influence of the crystal form of the copper phthalocyanine on the separation yield of copper-64 is shown. Preliminary tests using the ionic exchange technique for purification and changing of copper-64 sulfate to chloride form are carried out. The specific activity using the spectrophotometric technique, after the determination of the copper concentration in solution of copper-64, is calculated. (Author) [pt

  11. Copper in plants

    OpenAIRE

    Yruela, Inmaculada

    2005-01-01

    Copper is an essential metal for normal plant growth and development, although it is also potentially toxic. Copper participates in numerous physiological processes and is an essential cofactor for many metalloproteins, however, problems arise when excess copper is present in cells. Excess copper inhibits plant growth and impairs important cellular processes (i.e., photosynthetic electron transport). Since copper is both an essential cofactor and a toxic element, involving a complex network o...

  12. A mechanistic study of the uniform corrosion of copper in compacted clay-sand soil

    International Nuclear Information System (INIS)

    Litke, C.D.; Ryan, S.R.; King, F.

    1992-08-01

    The results of a study of the mechanism of uniform corrosion of copper under simulated nuclear fuel waste disposal conditions are presented. Evidence is given that suggests that the rate-controlling process is the transport of copper corrosion products away from the corroding surface. In the experiments described here, the copper diffused through a column of compacted clay-sand buffer. The properties of the buffer material, especially its ability to sorb copper species, are significant in determining the rate of uniform corrosion of copper. The evidence that copper diffusion is rate-controlling stems from the effect of γ-radiation on the tests. In the presence of γ-radiation, copper diffused farther along the column of compacted buffer material than in the unirradiated tests, but the corrosion rate was lower. These two effects can be best explained in terms of a slow copper-diffusion process. Irradiation is thought to reduce the extent of sorption of copper by the clay component of the buffer. This results in a more mobile copper species and a smaller interfacial flux of copper (i.e., a lower corrosion rate)

  13. Study on copper kinetics in processing sulphide ore mixed with copper and zinc with sulfuric acid leaching under pressure

    Science.gov (United States)

    Wen-bo, LUO; Ji-kun, WANG; Yin, GAN

    2018-01-01

    Sulphide ore mixed with copper and zinc is processed with pressure acid leaching. Research is conducted on the copper kinetic. The stirring rate is set at 600 rpm which could eliminate the influence of external diffusions. Research is conducted on the factors affecting the copper leaching kinetic are temperature, pressure, concentration of sulfuric acid, particle size. The result shows that the apparent activity energy is 50.7 KJ/mol. We could determine that the copper leaching process is shrinking core model of chemical reaction control and work out the leaching equation.

  14. Effects of Small Additions of Copper and Copper + Nickel on the Oxidation Behavior of Iron

    Science.gov (United States)

    Webler, Bryan; Yin, Lan; Sridhar, Seetharaman

    2008-10-01

    This study was undertaken to investigate the effect of small amounts of copper and copper + nickel additions on the oxidation rate and oxide/metal interface microstructure of iron. Three iron-based alloys were compared: 0.3 wt pct copper, 0.3 wt pct copper-0.1 wt pct nickel, and 0.3 wt pct copper-0.05 wt pct nickel. Alloy samples were oxidized in air at 1150 °C for 60, 300, and 600 seconds. Pure iron oxidized for 300 seconds was used as a reference material. The parabolic oxidation rate for the iron-copper alloy did not differ from that of pure iron, but the parabolic rate for the nickel-containing alloys decreased by a factor of 2. The microstructure of the iron-copper alloy consisted of a thin, copper-rich layer at the oxide/metal interface. Both nickel-containing alloys had perturbed oxide/metal interfaces consisting of alternating solid/liquid regions. The application of ternary alloy interface stability theories show that the perturbed interfaces arise from unequal diffusivities in the solid γ-iron phase. It is suggested that this perturbed interface microstructure causes the observed decrease in oxidation rate, by limiting the iron supply to the oxide.

  15. Characteristics and antimicrobial activity of copper-based materials

    Science.gov (United States)

    Li, Bowen

    In this study, copper vermiculite was synthesized, and the characteristics, antimicrobial effects, and chemical stability of copper vermiculite were investigated. Two types of copper vermiculite materials, micron-sized copper vermiculite (MCV) and exfoliated copper vermiculite (MECV), are selected for this research. Since most of the functional fillers used in industry products, such as plastics, paints, rubbers, papers, and textiles prefer micron-scaled particles, micron-sized copper vermiculite was prepared by jet-milling vermiculite. Meanwhile, since the exfoliated vermiculite has very unique properties, such as high porosity, specific surface area, high aspect ratio of laminates, and low density, and has been extensively utilized as a functional additives, exfoliated copper vermiculite also was synthesized and investigated. The antibacterial efficiency of copper vermiculite was qualitatively evaluated by the diffusion methods (both liquid diffusion and solid diffusion) against the most common pathogenic species: Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Klebsiella pneumoniae (K. pneumoniae). The result showed that the release velocity of copper from copper vermiculite is very slow. However, copper vermiculite clearly has excellent antibacterial efficiency to S. aureus, K. pneumoniae and E. coli. The strongest antibacterial ability of copper vermiculite is its action on S. aureus. The antibacterial efficiency of copper vermiculite was also quantitatively evaluated by determining the reduction rate (death rate) of E. coli versus various levels of copper vermiculite. 10 ppm of copper vermiculite in solution is sufficient to reduce the cell population of E. coli, while the untreated vermiculite had no antibacterial activity. The slow release of copper revealed that the antimicrobial effect of copper vermiculite was due to the strong interactions between copper ions and bacteria cells. Exfoliated copper vermiculite has even stronger

  16. A study of the processes during high temperature oxidation that control surface hot shortness in copper-containing low carbon steels

    Science.gov (United States)

    Webler, Bryan A.

    Copper is a problematic residual element in electric arc furnace steel production because it leads to "surface hot shortness," a cracking defect that occurs during hot rolling of steel. The cracking arises from a liquid, copper-rich phase that penetrates into and embrittles the austenite grain boundaries. The liquid forms because copper is nobler than iron and enriches at the oxide/metal interface during oxidation of iron after casting and reheating prior to hot rolling. This cracking can be reduced or eliminated by controlling the distribution of the copper-rich layer, i.e. preventing it from penetrating down the austenite grain boundaries. This study investigated the effect of alloy chemistry on the oxidation behavior and copper-rich liquid phase evolution. Alloy compositions were selected such that effects of copper, nickel, and reactive impurities (manganese, aluminum, and silicon) can be isolated. Industrially produced low carbon steels with varying copper, nickel and silicon contents were also studied. Alloys were oxidized in air or water vapor for times up to one hour at 1150°C. Oxidizing heat treatments were conducted in a thermogravimetric setup where the weight change could be measured during oxidation. Scanning electron microscopy was used to investigate in detail the oxide/metal interfaces. The modeling work focused on describing the enrichment and subsequent growth of the copper-rich layer. A fixed grid finite difference model was developed that predicts the evolution of the enriched region from given oxidation kinetics. The model predictions were validated under a variety of conditions using an iron - 0.3 wt% copper alloy. Deviations from the model predictions in these alloys suggest a critical amount of separated copper is necessary for substantial grain boundary penetration to occur and the required amount decreases when the gas contains water vapor. The parabolic oxidation rate for the iron-copper alloy did not differ from that of pure iron, but

  17. Body of Knowledge (BOK) for Copper Wire Bonds

    Science.gov (United States)

    Rutkowski, E.; Sampson, M. J.

    2015-01-01

    Copper wire bonds have replaced gold wire bonds in the majority of commercial semiconductor devices for the latest technology nodes. Although economics has been the driving mechanism to lower semiconductor packaging costs for a savings of about 20% by replacing gold wire bonds with copper, copper also has materials property advantages over gold. When compared to gold, copper has approximately: 25% lower electrical resistivity, 30% higher thermal conductivity, 75% higher tensile strength and 45% higher modulus of elasticity. Copper wire bonds on aluminum bond pads are also more mechanically robust over time and elevated temperature due to the slower intermetallic formation rate - approximately 1/100th that of the gold to aluminum intermetallic formation rate. However, there are significant tradeoffs with copper wire bonding - copper has twice the hardness of gold which results in a narrower bonding manufacturing process window and requires that the semiconductor companies design more mechanically rigid bonding pads to prevent cratering to both the bond pad and underlying chip structure. Furthermore, copper is significantly more prone to corrosion issues. The semiconductor packaging industry has responded to this corrosion concern by creating a palladium coated copper bonding wire, which is more corrosion resistant than pure copper bonding wire. Also, the selection of the device molding compound is critical because use of environmentally friendly green compounds can result in internal CTE (Coefficient of Thermal Expansion) mismatches with the copper wire bonds that can eventually lead to device failures during thermal cycling. Despite the difficult problems associated with the changeover to copper bonding wire, there are billions of copper wire bonded devices delivered annually to customers. It is noteworthy that Texas Instruments announced in October of 2014 that they are shipping microcircuits containing copper wire bonds for safety critical automotive applications

  18. Antibacterial effect of 317L stainless steel contained copper in prevention of implant-related infection in vitro and in vivo.

    Science.gov (United States)

    Chai, Hongwei; Guo, Lei; Wang, Xiantao; Fu, Yuping; Guan, Junlin; Tan, Lili; Ren, Ling; Yang, Ke

    2011-11-01

    Bone and intramedullary bacterial infections are one of the most serious complications of the surgical repair of fractures. To reduce the incidence of implant-related infections, several biomaterial surface treatments with integrated antibiotics, antiseptics, or metal ions have been developed for implants. In this study, we evaluated the antibacterial activity and biocompatibility of 317L stainless steel containing 4.5% copper alloy (317L-Cu) in vitro and in vivo using an animal model. Common pathogens of implant-related infections are Staphylococcus aureus and Escherichia coli, which were injected into implant materials to study their antimicrobial potential. We compared antimicrobial potential of 317L-Cu with 317L stainless steel (317L) and titanium (Ti-6Al-4V) alloys as controls. Compared with controls, 317L-Cu materials inhibited colonization by both bacteria in vitro and in vivo. Compared with 317L and Ti-6Al-4V controls, 317L-Cu showed no significant difference in colony formation of osteoblast-like cells on metal surfaces after 72 h of incubation in vitro. Metal screws containing these materials were also made for our vivo study in a rabbit model. Tissue-implants were analyzed for infection and inflammatory changes by hematoxylin-eosin staining of implants in bone. The screw tract inflammation and infection of 317L-Cu was minimal, although some inflammatory cells gathered at acutely infected sites. In addition, after materials had been implanted for 14 days in vivo, the expression of insulin-like growth factor-1 (IGF-1) in osteoblasts around 317L-Cu screws tracts had increased compared with 317L and Ti-6Al-4V controls. Overall, 317L-Cu demonstrated strong antimicrobial activity and biocompatibility in vitro and in vivo and may be used as a biomaterial to reduce implant-related infections.

  19. Aquatic Life Criteria - Copper

    Science.gov (United States)

    Documents pertain to Aquatic Life Ambient Water Quality criteria for Copper (2007 Freshwater, 2016 Estuarine/marine). These documents contain the safe levels of Copper in water that should protect to the majority of species.

  20. Antwerp Copper Plates

    DEFF Research Database (Denmark)

    Wadum, Jørgen

    1999-01-01

    In addition to presenting a short history of copper paintings, topics detail artists’ materials and techniques, as well as aspects of the copper industry, including mining, preparation and trade routes....

  1. Demystifying Controlling Copper Corrosion

    Science.gov (United States)

    The LCR systematically misses the highest health and corrosion risk sites for copper. Additionally, there are growing concerns for WWTP copper in sludges and discharge levels. There are many corrosion control differences between copper and lead. This talk explains the sometimes c...

  2. The effect of copper on some laboratory indices of Clarias ...

    African Journals Online (AJOL)

    fish to copper in water, at concentrations above 1.0mg CuSO4/g elicits adverse haematological responses and causes homeostatic imbalance. To prevent pollution, it is expedient that there be regulation of the amount of copper sulphate used in cocoa farms, as occurs in south western Nigeria. Key words: Clarias gariepinus ...

  3. Thermal conductivity and thermal diffusivity

    International Nuclear Information System (INIS)

    Hust, J.G.

    1983-01-01

    This chapter examines the heat transfer properties of solids, with emphasis on the behavior of pure metals and alloys. Topics considered include electronic conduction, magnetic field effects, lattice conduction, measuring methods, specimen size, uncertainty, thermal anchoring, radial heat loss, thermal conductivity apparatus, thermal diffusivity apparatus, empirical correlations, the Wiedemann-Franz-Lorenz law, Matthiessen's rule, low-temperature correlation, predictive techniques, crystalline dielectrics, and disordered dielectrics. The materials examined include copper, aluminium, binary alloys, structural alloys, and structural composites

  4. Vermiculite decorated with copper nanoparticles: Novel antibacterial hybrid material

    Science.gov (United States)

    Drelich, Jaroslaw; Li, Bowen; Bowen, Patrick; Hwang, Jiann-Yang; Mills, Owen; Hoffman, Daniel

    2011-09-01

    Vermiculite decorated with copper nanoparticles is a new antibacterial material that was prepared in this study through ion-exchange process and hydrogen reduction. The replacement of magnesium ions in interlayer structure was carried out using concentrated copper sulfate solutions at elevated temperature. Copper ions were reduced to elemental copper at 400-600 °C using hydrogen as the reducing agent. During the reduction process copper diffused primarily to vermiculite surface regions and formed copper nanoparticles with a broad range of sizes, from ˜1 to 400 nm. Strong adhesion of copper nanoparticles to the vermiculite carrier makes this hybrid very stable and durable. The new vermiculite-metallic copper hybrid material shows strong antibacterial activity against Staphylococcus aureus at 37 °C. Vermiculite is an inexpensive mineral that is very stable under a wide range of industrial and environmental conditions, and extensively used as filler in fireproof materials, plastics, paints and lightweight concrete, so the addition of copper as an antibacterial agent opens new avenues for the application of vermiculite in consumer products and other areas.

  5. Viscosity and density models for copper electrorefining electrolytes

    OpenAIRE

    Kalliomäki Taina; Aji Arif T.; Aromaa Jari; Lundström Mari

    2016-01-01

    Viscosity and density are highly important physicochemical properties of copper electrolyte since they affect the purity of cathode copper and energy consumption [1, 2] affecting the mass and heat transfer conditions in the cell [3]. Increasing viscosity and density decreases the rate in which the anode slime falls to the bottom of the cell [4, 5] and lowers the diffusion coefficient of cupric ion (DCu2+) [6]. Decreasing the falling rate of anode slime increases movement of the slime to other...

  6. Low-Profile Diffuser

    Science.gov (United States)

    Martin, Michael A.; Nettles, Mindy

    2015-01-01

    The propellant tanks used in liquid rockets require pressurization gases in order to maintain tank pressure while the tanks are being drained during engine operation. The pressurization gas, which is typically much warmer than the relatively cold propellants in the tank, must be introduced into the empty ullage space at the top of the tank. The purpose of the diffuser is to control the flow of the gas into the tank in order to prevent direct impingement of the gas on the liquid surface and/or the tank walls. If the diffuser did not perform those tasks, the warm gas can create excess heat transfer causing an increase in the amount of pressurization mass required. Typical diffusers are long vertical cylinders that create a large exit area in order to minimize gas velocities. However, long vertical cylinders limit the amount of liquid that can be loaded into the tank in order not to have the liquid surface near the diffuser. A design goal for a pressurization diffuser is to create uniform flow in order to prevent jets that can impact the liquid surface and/or tank walls. The purpose of the task was to create a diffuser design that had a lower vertical profile (in order to be able to raise the liquid surface) while still maintaining uniform flow.

  7. Effect of copper on multiple successional stages of a marine fouling assemblage.

    Science.gov (United States)

    McElroy, David J; Hochuli, Dieter F; Doblin, Martina A; Murphy, Richard J; Blackburn, Robert J; Coleman, Ross A

    2017-11-01

    Copper based paints are used to prevent fouling on the hulls of ships. The widely documented effect of copper on hull assemblages may be primarily due to direct effects on the invertebrates themselves or indirect effects from copper absorbed into the microbial biofilm before settlement has commenced. Artificial units of habitat were exposed to varied regimes of copper to examine (1) the photosynthetic efficiency and pigments of early-colonising biofilms, and (2) subsequent macroinvertebrate assemblage change in response to the different regimes of copper. Macroinvertebrate assemblages were found to be less sensitive to the direct effects of copper than indirect effects as delivered through biofilms that have been historically exposed to copper, with some species more tolerant than others. This raises further concern for the efficacy of copper as a universal antifoulant on the hulls of ships, which may continue to assist the invasion of copper-tolerant invertebrate species.

  8. Bronnen van diffuse bodembelasting

    NARCIS (Netherlands)

    Lijzen JPA; Ekelenkamp A; LBG; DGM/BO

    1995-01-01

    The aim of this study was to support the policy on preventive soil protection with information on the diffuse (non-local) emissions to soil and the influence on future soil quality. This study is related to inventories on (potential) sources of local soil pollution (e.g. industrial areas,

  9. High temperature oxidation of copper and copper aluminium alloys: Impact on furnace side wall cooling systems

    Science.gov (United States)

    Plascencia Barrera, Gabriel

    The high temperature oxidation behaviours of copper and dilute Cu-Al alloys were investigated. Experiments were carried out by: (i) Oxidizing under various oxygen potentials at different temperatures using a combined TG-DTA apparatus. (ii) Oxidizing in a muffle furnace (in air) at different temperatures for extended periods of time. The oxidation mechanisms were evaluated based upon the kinetic data obtained as well as by X-ray diffraction and microscopical (SEM and optical) analyses. It was found that oxidation of copper strongly depends on the temperature. Two distinct mechanisms were encountered. Between 300 and 500°C, the oxidation rate is controlled by lateral growth of the oxide on the metal surface, whereas between 600 and 1000°C oxidation is controlled by lattice diffusion of copper ions through the oxide scale. On the other hand, the partial pressure of oxygen only has a small effect on the oxidation of copper. Alloy oxidation is also dependent on the temperature. As temperature increases, more aluminium is required to protect copper from being oxidized. It was shown that if the amount of oxygen that dissolves in the alloy exceeds the solubility limit of oxygen in copper, an internal oxidation layer will develop, leading to the formation of a tarnishing scale. On the other hand if the oxygen content in the alloy lies below the solubility limit of oxygen in copper, no oxidation products will form since a tight protective alumina layer will form on the alloy surface. Surface phenomena may affect the oxidation behaviour of dilute Cu-Al alloys. Immersion tests in molten copper matte and copper converting slag, using laboratory scale cooling elements with various copper based materials, were conducted. Results from these tests showed that alloying copper with 3 to 4 wt% Al decreases the oxidation rate of pure copper by 4 orders of magnitude; however due to a significant drop in thermal conductivity, the ability to extract heat is compromised, leading to

  10. Effectiveness acidic pre-cleaning for copper-gold ore

    Directory of Open Access Journals (Sweden)

    Antonio Clareti Pereira

    Full Text Available Abstract The presence of copper-bearing minerals is known to bring on many challenges during the cyanidation of gold ore, like high consumption of cyanide and low extraction of metal, which are undesirable impacts on the auriferous recovery in the subsequent process step. The high copper solubility in cyanide prevents the direct use of classical hydrometallurgical processes for the extraction of gold by cyanidation. Additionally, the application of a conventional flotation process to extract copper is further complicated when it is oxidized. As a result, an acid pre-leaching process was applied in order to clean the ore of these copper minerals that are cyanide consumers. The objective was to evaluate the amount of soluble copper in cyanide before and after acidic cleaning. From a gold ore containing copper, the study selected four samples containing 0.22%, 0.55%, 1.00% and 1.36% of copper. For direct cyanidation of the ore without pre-treatment, copper extraction by cyanide complexing ranged from 8 to 83%. In contrast, the pre-treatment carried out with sulfuric acid extracted 24% to 99% of initial copper and subsequent cyanidation extracted 0.13 to 1.54% of initial copper. The study also showed that the copper contained in the secondary minerals is more easily extracted by cyanide (83%, being followed by the copper oxy-hydroxide minerals (60%, while the copper contained in the manganese oxide is less complexed by cyanide (8% a 12%. It was possible to observe that minerals with low acid solubility also have low solubility in cyanide. Cyanide consumption decreased by about 2.5 times and gold recovery increased to above 94% after acidic pre-cleaning.

  11. Influences of Corrosive Sulfur on Copper Wires and Oil-Paper Insulation in Transformers

    Directory of Open Access Journals (Sweden)

    Jian Li

    2011-10-01

    Full Text Available Oil-impregnated paper is widely used in power transmission equipment as a reliable insulation. However, copper sulphide deposition on oil-paper insulation can lead to insulation failures in power transformers. This paper presents the influences of copper sulfur corrosion and copper sulphide deposition on copper wires and oil-paper insulation in power transformers. Thermal aging tests of paper-wrapped copper wires and bare copper wires in insulating oil were carried out at 130 °C and 150 °C in laboratory. The corrosive characteristics of paper-wrapped copper wires and bare copper wires were analyzed. Dielectric properties of insulation paper and insulating oil were also analyzed at different stages of the thermal aging tests using a broadband dielectric spectrometer. Experiments and analysis results show that copper sulfide deposition on surfaces of copper wires and insulation paper changes the surface structures of copper wires and insulation paper. Copper sulfur corrosion changes the dielectric properties of oil-paper insulation, and the copper sulfide deposition greatly reduces the electrical breakdown strength of oil-paper insulation. Metal passivator is capable of preventing copper wires from sulfur corrosion. The experimental results are helpful for investigations for fault diagnosis of internal insulation in power transformers.

  12. Microstructure Effect on Electromigration-Induced Degradation of Inlaid Copper Interconnects

    International Nuclear Information System (INIS)

    Zschech, E.; Meyer, M.A.; Prinz, H.; Zienert, I.; Langer, E.; Geisler, H.; Grafe, M.

    2004-01-01

    Electromigration-induced degradation processes in via/line dual inlaid copper interconnect test structures are discussed based on experimental studies. Void formation, growth and movement, and consequently interconnect degradation, depend on both interface bonding and copper microstructure. Void movement along the copper line and void growth in the via are discontinuous processes, wherein their step-like behavior is caused by copper microstructure. Microstructure studies and microstructure monitoring are becoming more important for strengthened top interfaces of copper lines, e. g. by local alloying of the copper or by applying an additional coating on top of the polished copper lines. As a result of this interface engineering, the contribution of grain boundary diffusion becomes increasingly important for the directed mass transport and for electromigration-induced degradation

  13. Copper and silver halates

    CERN Document Server

    Woolley, EM; Salomon, M

    2013-01-01

    Copper and Silver Halates is the third in a series of four volumes on inorganic metal halates. This volume presents critical evaluations and compilations for halate solubilities of the Group II metals. The solubility data included in this volume are those for the five compounds, copper chlorate and iodate, and silver chlorate, bromate and iodate.

  14. A Case of Isolated Elevated Copper Levels during Pregnancy

    Directory of Open Access Journals (Sweden)

    LaToya R. Walker

    2011-01-01

    Full Text Available Introduction. Outside of Wilson's Disease, abnormal copper metabolism is a rare condition. In pregnancy, excess copper levels can be associated with intrauterine growth restriction, preeclampsia and neurological disease. Case Report. A 32 year old Gravida 4 para 2012 with an obstetrical history complicated by elevated copper levels presented for routine prenatal care. Her children had elevated copper levels at birth, with her firstborn child being diagnosed with autism and suffering three myocardial infarctions and being treated for elevated copper levels. During her prior pregnancies, she declined treatment for her elevated copper levels. During this pregnancy, she had declined chelation therapy and instead choose zinc therapy. She delivered a healthy infant with normal copper levels. Conclusion. Alterations in copper metabolism are rare, the consequences in pregnancy can be devastating. While isolated elevations of copper in pregnancy is exceedingly rare, it is treated the same as Wilson's disease. The goal is to prevent fetal growth restricting and neurological sequelae in the newborn and preeclampsia in the mother. Counseling, along with treatment options and timely delivery can greatly improve neonatal and maternal outcome.

  15. Bioaccessibility and Solubility of Copper in Copper-Treated Lumber

    Science.gov (United States)

    Micronized copper (MC)-treated lumber is a recent replacement for Chromated Copper Arsenate (CCA) and Ammonium Copper (AC)-treated lumbers; though little is known about the potential risk of copper (Cu) exposure from incidental ingestion of MC-treated wood. The bioaccessibility o...

  16. Posttranslational regulation of copper transporters

    NARCIS (Netherlands)

    van den Berghe, P.V.E.

    2009-01-01

    The transition metal copper is an essential cofactor for many redox-active enzymes, but excessive copper can generate toxic reactive oxygen species. Copper homeostasis is maintained by highly conserved proteins, to balance copper uptake, distribution and export on the systemic and cellular level.

  17. Canine Copper-Associated Hepatitis

    NARCIS (Netherlands)

    Dirksen, Karen|info:eu-repo/dai/nl/412424428; Fieten, Hille|info:eu-repo/dai/nl/314112596

    2017-01-01

    Copper-associated hepatitis is recognized with increasing frequency in dogs. The disease is characterized by centrolobular hepatic copper accumulation, leading to hepatitis and eventually cirrhosis. The only way to establish the diagnosis is by histologic assessment of copper distribution and copper

  18. COPPER CABLE RECYCLING TECHNOLOGY

    International Nuclear Information System (INIS)

    Chelsea Hubbard

    2001-01-01

    The United States Department of Energy (DOE) continually seeks safer and more cost-effective technologies for use in deactivation and decommissioning (D and D) of nuclear facilities. The Deactivation and Decommissioning Focus Area (DDFA) of the DOE's Office of Science and Technology (OST) sponsors large-scale demonstration and deployment projects (LSDDPs). At these LSDDPs, developers and vendors of improved or innovative technologies showcase products that are potentially beneficial to the DOE's projects and to others in the D and D community. Benefits sought include decreased health and safety risks to personnel and the environment, increased productivity, and decreased costs of operation. The Idaho National Engineering and Environmental Laboratory (INEEL) generated a list of statements defining specific needs and problems where improved technology could be incorporated into ongoing D and D tasks. One such need is to reduce the volume of waste copper wire and cable generated by D and D. Deactivation and decommissioning activities of nuclear facilities generates hundreds of tons of contaminated copper cable, which are sent to radioactive waste disposal sites. The Copper Cable Recycling Technology separates the clean copper from contaminated insulation and dust materials in these cables. The recovered copper can then be reclaimed and, more importantly, landfill disposal volumes can be reduced. The existing baseline technology for disposing radioactively contaminated cables is to package the cables in wooden storage boxes and dispose of the cables in radioactive waste disposal sites. The Copper Cable Recycling Technology is applicable to facility decommissioning projects at many Department of Energy (DOE) nuclear facilities and commercial nuclear power plants undergoing decommissioning activities. The INEEL Copper Cable Recycling Technology Demonstration investigated the effectiveness and efficiency to recycle 13.5 tons of copper cable. To determine the effectiveness

  19. Thermal cycling tests of actively cooled beryllium copper joints

    Energy Technology Data Exchange (ETDEWEB)

    Roedig, M.; Duwe, R.; Linke, J.; Schuster, A.; Wiechers, B. [Forschungszentrum Juelich GmbH (Germany)

    1998-01-01

    Screening tests (steady state heating) and thermal fatigue tests with several kinds of beryllium-copper joints have been performed in an electron beam facility. Joining techniques under investigation were brazing with silver containing and silver-free braze materials, hot isostatic pressing (HIP) and diffusion bonding (hot pressing). Best thermal fatigue performance was found for the brazed samples. (author)

  20. Organization of copper nanoclusters in Langmuir–Blodgett films

    Indian Academy of Sciences (India)

    The Langmuir–Blodgett films of ODSA formed from subphase containing copper ions were first subjected to sulphidation (S) using sodium sulphide and then hydrogenated (H) using hydrogen gas. Diffuse reflectance UV-visible spectroscopy (DIR-UV-vis), X-ray photoelectron spectroscopy (XPS) and transmission electron ...

  1. In-situ x-ray absorption study of copper films in ground water solutions

    International Nuclear Information System (INIS)

    Kvashnina, K.O.; Butorin, S.M.; Modin, A.; Soroka, I.; Marcellini, M.; Nordgren, J.; Guo, J.-H.; Werme, L.

    2007-01-01

    This study illustrates how the damage from copper corrosion can be reduced by modifying the chemistry of the copper surface environment. The surface modification of oxidized copper films induced by chemical reaction with Cl - and HCO 3 - in aqueous solutions was monitored by in situ X-ray absorption spectroscopy. The results show that corrosion of copper can be significantly reduced by adding even a small amount of sodium bicarbonate. The studied copper films corroded quickly in chloride solutions, whereas the same solution containing 1.1 mM HCO 3 - prevented or slowed down the corrosion processes

  2. Formation kinetics of copper-related light-induced degradation in crystalline silicon

    International Nuclear Information System (INIS)

    Lindroos, J.; Savin, H.

    2014-01-01

    Light-induced degradation (LID) is a deleterious effect in crystalline silicon, which is considered to originate from recombination-active boron-oxygen complexes and/or copper-related defects. Although LID in both cases appears as a fast initial decay followed by a second slower degradation, we show that the time constant of copper-related degradation increases with increasing boron concentration in contrast to boron-oxygen LID. Temperature-dependent analysis reveals that the defect formation is limited by copper diffusion. Finally, interface defect density measurements confirm that copper-related LID is dominated by recombination in the wafer bulk

  3. Copper resistance determinants in bacteria.

    Science.gov (United States)

    Brown, N L; Rouch, D A; Lee, B T

    1992-01-01

    Copper is an essential trace element that is utilized in a number of oxygenases and electron transport proteins, but it is also a highly toxic heavy metal, against which all organisms must protect themselves. Known bacterial determinants of copper resistance are plasmid-encoded. The mechanisms which confer resistance must be integrated with the normal metabolism of copper. Different bacteria have adopted diverse strategies for copper resistance, and this review outlines what is known about bacterial copper resistance mechanisms and their genetic regulation.

  4. A demonstration of the antimicrobial effectiveness of various copper surfaces.

    Science.gov (United States)

    Champagne, Victor K; Helfritch, Dennis J

    2013-03-27

    Bacterial contamination on touch surfaces results in increased risk of infection. In the last few decades, work has been done on the antimicrobial properties of copper and its alloys against a range of micro-organisms threatening public health in food processing, healthcare and air conditioning applications; however, an optimum copper method of surface deposition and mass structure has not been identified. A proof-of-concept study of the disinfection effectiveness of three copper surfaces was performed. The surfaces were produced by the deposition of copper using three methods of thermal spray, namely, plasma spray, wire arc spray and cold spray The surfaces were then inoculated with meticillin-resistant Staphylococcus aureus (MRSA). After a two hour exposure to the surfaces, the surviving MRSA were assayed and the results compared.The differences in the copper depositions produced by the three thermal spray methods were examined in order to explain the mechanism that causes the observed differences in MRSA killing efficiencies. The cold spray deposition method was significantly more effective than the other methods. It was determined that work hardening caused by the high velocity particle impacts created by the cold spray technique results in a copper microstructure that enhances ionic diffusion, and copper ions are principally responsible for antimicrobial activity. This test showed significant microbiologic differences between coatings produced by different spray techniques and demonstrates the importance of the copper application technique. The cold spray technique shows superior anti-microbial effectiveness caused by the high impact velocity imparted to the sprayed particles which results in high dislocation density and high ionic diffusivity.

  5. LEACHING OF MALACHITE ORE IN AMMONIUM SULFATE SOLUTIONS AND PRODUCTION OF COPPER OXIDE

    Directory of Open Access Journals (Sweden)

    A. Ekmekyapar

    2015-03-01

    Full Text Available Abstract Malachite ore is one of the most important of oxidized copper ores. Copper production can be performed by using this ore. In this work, the leaching kinetics of malachite in ammonium sulfate solutions was investigated, and metallic copper was recovered by a cementation method from the resulting actual leach solution. Copper (II oxide was prepared by an isothermal oxidation method from the cement copper. In the leaching experiments, the effects of reaction temperature, particle size, and stirring speed on copper leaching from malachite ore were studied. In the cementation experiments, metallic zinc was used as the reductant metal to recover the copper from the solution. Thermal oxidation of cement copper was performed under isothermal conditions. It was found that the leaching rate increased with increasing stirring speed and temperature, and decreased with particle size. It was observed that the leaching reaction fit to diffusion through the product layer. The activation energy of the leaching process was determined to be 25.4 kJ/mol. It was determined that the copper content of the metallic product obtained by the cementation method increased up to 96%. It was found that copper oxide prepared from cement copper had a tenorite structure.

  6. Micromachining with copper lasers

    Science.gov (United States)

    Knowles, Martyn R. H.; Bell, Andy; Foster-Turner, Gideon; Rutterford, Graham; Chudzicki, J.; Kearsley, Andrew J.

    1997-04-01

    In recent years the copper laser has undergone extensive development and has emerged as a leading and unique laser for micromachining. The copper laser is a high average power (10 - 250 W), high pulse repetition rate (2 - 32 kHz), visible laser (511 nm and 578 nm) that produces high peak power (typically 200 kW), short pulses (30 ns) and very good beam quality (diffraction limited). This unique set of laser parameters results in exceptional micro-machining in a wide variety of materials. Typical examples of the capabilities of the copper laser include the drilling of small holes (10 - 200 micrometer diameter) in materials as diverse as steel, ceramic, diamond and polyimide with micron precision and low taper (less than 1 degree) cutting and profiling of diamond. Application of the copper laser covers the electronic, aerospace, automotive, nuclear, medical and precision engineering industries.

  7. Sliding Friction of Copper

    National Research Council Canada - National Science Library

    Liu, Tung

    1963-01-01

    .... With less clean surfaces, the coefficient of friction obtained was about 0.4. Since the degree of cleanliness cannot be controlled quantitatively, the friction - load curve of sliding copper pairs in air exhibits a bifurcation characteristic...

  8. Diffuse scattering

    Energy Technology Data Exchange (ETDEWEB)

    Kostorz, G. [Eidgenoessische Technische Hochschule, Angewandte Physik, Zurich (Switzerland)

    1996-12-31

    While Bragg scattering is characteristic for the average structure of crystals, static local deviations from the average lattice lead to diffuse elastic scattering around and between Bragg peaks. This scattering thus contains information on the occupation of lattice sites by different atomic species and on static local displacements, even in a macroscopically homogeneous crystalline sample. The various diffuse scattering effects, including those around the incident beam (small-angle scattering), are introduced and illustrated by typical results obtained for some Ni alloys. (author) 7 figs., 41 refs.

  9. LEP copper accelerating cavities

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    These copper cavities were used to generate the radio frequency electric field that was used to accelerate electrons and positrons around the 27-km Large Electron-Positron (LEP) collider at CERN, which ran from 1989 to 2000. The copper cavities were gradually replaced from 1996 with new superconducting cavities allowing the collision energy to rise from 90 GeV to 200 GeV by mid-1999.

  10. Temporal aspects of copper homeostasis and its crosstalk with hormones

    Directory of Open Access Journals (Sweden)

    Lola ePeñarrubia

    2015-04-01

    Full Text Available To cope with the dual nature of copper as being essential and toxic for cells, plants temporarily adapt the expression of copper homeostasis components to assure its delivery to cuproproteins while avoiding the interference of potential oxidative damage derived from both copper uptake and photosynthetic reactions during light hours. The circadian clock participates in the temporal organization of coordination of plant nutrition adapting metabolic responses to the daily oscillations. This timely control improves plant fitness and reproduction and holds biotechnological potential to drive increased crop yields. Hormonal pathways, including those of abscisic acid, gibberellins, ethylene, auxins, and jasmonates are also under direct clock and light control, both in mono and dicotyledons. In this review, we focus on copper transport in Arabidopsis thaliana and Oryza sativa and the presumable role of hormones in metal homeostasis matching nutrient availability to growth requirements and preventing metal toxicity. The presence of putative hormone-dependent regulatory elements in the promoters of copper transporters genes suggests hormonal regulation to match special copper requirements during plant development. Spatial and temporal processes that can be affected by hormones include the regulation of copper uptake into roots, intracellular trafficking and compartmentalisation, and long-distance transport to developing vegetative and reproductive tissues. In turn, hormone biosynthesis and signalling are also influenced by copper availability, which suggests reciprocal regulation subjected to temporal control by the central oscillator of the circadian clock. This transcriptional regulatory network, coordinates environmental and hormonal signalling with developmental pathways to allow enhanced micronutrient acquisition efficiency.

  11. Copper wire bonding

    CERN Document Server

    Chauhan, Preeti S; Zhong, ZhaoWei; Pecht, Michael G

    2014-01-01

    This critical volume provides an in-depth presentation of copper wire bonding technologies, processes and equipment, along with the economic benefits and risks.  Due to the increasing cost of materials used to make electronic components, the electronics industry has been rapidly moving from high cost gold to significantly lower cost copper as a wire bonding material.  However, copper wire bonding has several process and reliability concerns due to its material properties.  Copper Wire Bonding book lays out the challenges involved in replacing gold with copper as a wire bond material, and includes the bonding process changes—bond force, electric flame off, current and ultrasonic energy optimization, and bonding tools and equipment changes for first and second bond formation.  In addition, the bond–pad metallurgies and the use of bare and palladium-coated copper wires on aluminum are presented, and gold, nickel and palladium surface finishes are discussed.  The book also discusses best practices and re...

  12. Chemical stability of copper-canisters in deep repository

    International Nuclear Information System (INIS)

    Ahonen, L.

    1995-12-01

    The spent fuel from Finnish nuclear reactors is planned to be encapsulated in thick-walled copper-iron canisters and placed deep into the bedrock. The copper wall of the canister provides a long-time shield against corrosion, preventing the high-level nuclear fuel from contact with ground water. In the report, stability of metallic copper and its possible corrosion reactions in the conditions of deep bedrock are evaluated by means of thermo-dynamic calculations. (90 refs., 28 figs., 11 tabs.)

  13. Effectiveness acidic pre-cleaning for copper-gold ore

    OpenAIRE

    Pereira, Antonio Clareti; Barbosa, Viviane da Silva Borges

    2017-01-01

    Abstract The presence of copper-bearing minerals is known to bring on many challenges during the cyanidation of gold ore, like high consumption of cyanide and low extraction of metal, which are undesirable impacts on the auriferous recovery in the subsequent process step. The high copper solubility in cyanide prevents the direct use of classical hydrometallurgical processes for the extraction of gold by cyanidation. Additionally, the application of a conventional flotation process to extract ...

  14. Relativistic diffusion.

    Science.gov (United States)

    Haba, Z

    2009-02-01

    We discuss relativistic diffusion in proper time in the approach of Schay (Ph.D. thesis, Princeton University, Princeton, NJ, 1961) and Dudley [Ark. Mat. 6, 241 (1965)]. We derive (Langevin) stochastic differential equations in various coordinates. We show that in some coordinates the stochastic differential equations become linear. We obtain momentum probability distribution in an explicit form. We discuss a relativistic particle diffusing in an external electromagnetic field. We solve the Langevin equations in the case of parallel electric and magnetic fields. We derive a kinetic equation for the evolution of the probability distribution. We discuss drag terms leading to an equilibrium distribution. The relativistic analog of the Ornstein-Uhlenbeck process is not unique. We show that if the drag comes from a diffusion approximation to the master equation then its form is strongly restricted. The drag leading to the Tsallis equilibrium distribution satisfies this restriction whereas the one of the Jüttner distribution does not. We show that any function of the relativistic energy can be the equilibrium distribution for a particle in a static electric field. A preliminary study of the time evolution with friction is presented. It is shown that the problem is equivalent to quantum mechanics of a particle moving on a hyperboloid with a potential determined by the drag. A relation to diffusions appearing in heavy ion collisions is briefly discussed.

  15. Ammonia diffusion through Nalophan™ bags.

    Science.gov (United States)

    Sironi, Selena; Eusebio, Lidia; Dentoni, Licinia; Capelli, Laura; Del Rosso, Renato

    2014-01-01

    The aim of the work is to verify the diffusion rate of ammonia through the Nalophan™ film that constitutes the sampling bag, considering storage times ranging from 1 to 26 h. The ammonia decay over time was evaluated using gas-chromatography for the quantification of ammonia concentration inside the bag. The research assesses the roles of both of ammonia and water concentration gradients at the polymeric film interface on the diffusion process. The results show that both the ammonia concentration gradient and, in a less pronounced way, the water concentration gradient are the main 'engines' of ammonia diffusion. Double bags seem to represent a simple solution for preventing ammonia losses during storage. Another interesting result concerns the role of the bag surface on the ammonia diffusion rate: the higher the surface/volume (S/V) ratio, the higher the ammonia diffusion rate through the polymeric film.

  16. Role of the P-Type ATPases, ATP7A and ATP7B in brain copper homeostasis

    Directory of Open Access Journals (Sweden)

    Jonathon eTelianidis

    2013-08-01

    Full Text Available Over the past two decades there have been significant advances in our understanding of copper homeostasis and the pathological consequences of copper dysregulation. Cumulative evidence is revealing a complex regulatory network of proteins and pathways that maintain copper homeostasis. The recognition of copper dysregulation as a key pathological feature in prominent neurodegenerative disorders such as Alzheimer’s, Parkinson’s and prion diseases has led to increased research focus on the mechanisms controlling copper homeostasis in the brain. The copper-transporting P-Type ATPases (copper-ATPases, ATP7A and ATP7B, are critical components of the copper regulatory network. Our understanding of the biochemistry and cell biology of these complex proteins has grown significantly since their discovery in 1993. They are large polytopic transmembrane proteins with six copper-binding motifs within the cytoplasmic N-terminal domain, eight transmembrane domains and highly conserved catalytic domains. These proteins catalyze ATP-dependent copper transport across cell membranes for the metallation of many essential cuproenzymes, as well as for the removal of excess cellular copper to prevent copper toxicity. A key functional aspect of these copper transporters is their copper-responsive trafficking between the trans-Golgi network and the cell periphery. ATP7A- and ATP7B-deficiency, due to genetic mutation, underlie the inherited copper transport disorders, Menkes and Wilson diseases, respectively. Their importance in maintaining brain copper homeostasis is underscored by the severe neuropathological deficits in these disorders. Herein we will review and update our current knowledge of these copper transporters in the brain and the central nervous system, their distribution and regulation, their role in normal brain copper homeostasis and how their absence or dysfunction contributes to disturbances in copper homeostasis and neurodegeneration.

  17. Antibacterial Effect of Copper on Microorganisms Isolated from Bovine Mastitis

    Science.gov (United States)

    Reyes-Jara, Angelica; Cordero, Ninoska; Aguirre, Juan; Troncoso, Miriam; Figueroa, Guillermo

    2016-01-01

    The antimicrobial properties of copper have been recognized for several years; applying these properties to the prevention of diseases such as bovine mastitis is a new area of research. The aim of the present study was to evaluate in vitro the antimicrobial activity of copper on bacteria isolated from subclinical and clinical mastitis milk samples from two regions in Chile. A total of 327 microorganisms were recovered between March and September 2013, with different prevalence by sample origin (25 and 75% from the central and southern regions of Chile, respectively). In the central region, Escherichia coli and coagulase negative Staphylococci (CNS) were the most frequently detected in clinical mastitis cases (33%), while in the southern region S. uberis, S. aureus, and CNS were detected with frequencies of 22, 21, and 18%, respectively. Antibiotic susceptibility studies revealed that 34% of isolates were resistant to one or more antibiotics and the resistance profile was different between bacterial species and origins of isolation of the bacteria. The minimum inhibitory concentration of copper (MIC-Cu) was evaluated in all the isolates; results revealed that a concentration as low as 250 ppm copper was able to inhibit the great majority of microorganisms analyzed (65% of isolates). The remaining isolates showed a MIC-Cu between 375 and 700 ppm copper, and no growth was observed at 1000 ppm. A linear relationship was found between the logarithm of viable bacteria number and time of contact with copper. With the application of the same concentration of copper (250 ppm), CNS showed the highest tolerance to copper, followed by S. uberis and S. aureus; the least resistant was E. coli. Based on these in vitro results, copper preparations could represent a good alternative to dipping solutions, aimed at preventing the presence and multiplication of potentially pathogenic microorganisms involved in bovine mastitis disease. PMID:27199953

  18. Diffusion bonding

    International Nuclear Information System (INIS)

    Anderson, R.C.

    1976-01-01

    A method is described for joining beryllium to beryllium by diffusion bonding. At least one surface portion of at least two beryllium pieces is coated with nickel. A coated surface portion is positioned in a contiguous relationship with another surface portion and subjected to an environment having an atmosphere at a pressure lower than ambient pressure. A force is applied on the beryllium pieces for causing the contiguous surface portions to abut against each other. The contiguous surface portions are heated to a maximum temperature less than the melting temperature of the beryllium, and the applied force is decreased while increasing the temperature after attaining a temperature substantially above room temperature. A portion of the applied force is maintained at a temperature corresponding to about maximum temperature for a duration sufficient to effect the diffusion bond between the contiguous surface portions

  19. Copper substrate as a catalyst for the oxidation of chemical vapor deposition-grown graphene

    International Nuclear Information System (INIS)

    Li, Zhiting; Zhou, Feng; Parobek, David; Shenoy, Ganesh J.; Muldoon, Patrick; Liu, Haitao

    2015-01-01

    We report the catalytic effect of copper substrate on graphene–oxygen reaction at high temperature. Previous studies showed that graphene grown on copper are mostly defect-free with strong oxidation resistance. We found that a freshly prepared copper-supported graphene sample can be completely oxidized in trace amount of oxygen (<3 ppm) at 600 °C within 2 h. Both X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) suggest that upon ambient air exposure, oxygen molecules diffuse into the space between graphene and copper, resulting in the formation of copper oxide which acts as catalytic sites for the graphene-oxygen reaction. This result has important implications for the characterization, processing, and storage of copper-supported graphene samples. - Graphical abstract: The copper substrate enhances the thermel oxidation of single-layer graphene. - Highlights: • A copper-supported graphene can be oxidized in Ar (O 2 <3 ppm, 600 °C, 2 h). • O 2 intercalates between graphene and copper upon exposure to air. • The copper foil should not be considered as an inert substrate

  20. Multipassage diffuser

    International Nuclear Information System (INIS)

    Lalis, A.; Rouviere, R.; Simon, G.

    1976-01-01

    A multipassage diffuser having 2p passages comprises a leak-tight cylindrical enclosure closed by a top cover and a bottom end-wall, parallel porous tubes which are rigidly assembled in sectors between tube plates and through which the gas mixture flows, the tube sectors being disposed at uniform intervals on the periphery of the enclosure. The top tube plates are rigidly fixed to an annular header having the shape of a half-torus and adapted to communicate with the tubes of the corresponding sector. Each passage is constituted by a plurality of juxtaposed sectors in which the mixture circulates in the same direction, the header being divided into p portions limited by radial partition-walls and each constituting two adjacent passages. The diffuser is provided beneath the bottom end-wall with p-1 leak-tight chambers each adapted to open into two different portions of the header, and with two collector-chambers each fitted with a nozzle for introducing the gas mixture and discharging the fraction of the undiffused mixture. By means of a central orifice formed in the bottom end-wall the enclosure communicates with a shaft for discharging the diffused fraction of the gas mixture

  1. Electrical conduction in composites containing copper core-copper ...

    Indian Academy of Sciences (India)

    Composites of nanometre-sized copper core-copper oxide shell with diameters in the range 6.1 to 7.3 nm dispersed in a silica gel were synthesised by a technique comprising reduction followed by oxidation of a suitably chosen precursor gel. The hot pressed gel powders mixed with nanometre-sized copper particles ...

  2. Iron-copper metallization for flexible solar/cell arrays

    Science.gov (United States)

    Lavendel, H. W.

    1983-01-01

    The feasibility of a copper-base metallization for shallow-junction cells applied in flexible solar arrays in space is discussed. This type of metallization will reduce usage of precious metals (such as silver), increase case of bonding (by welding or by soldering) and eliminate heavy high Z interconnects (such as molybdenum). The main points of concern are stability against thermally induced diffusion of copper into silicon which causes degradation of shallow cell junctions, and low series resistance of the contact with semiconductor which promotes cell efficiency.

  3. Influence of a hydrostatic pressure on the diffusion in metals having a cubic structure

    International Nuclear Information System (INIS)

    Beyeler, M.

    1969-01-01

    In view of obtaining informations on the structure of vacancies. We have determined, by diffusion experiments under high pressure, the activation volumes for self diffusion in different face centered cubic metals: silver, gold, copper, aluminium and in body centered cubic uranium (gamma phase). Activation volumes for noble metals diffusion in aluminium have also been investigated. The experimental results on gold, silver and copper are in good agreement with most of the theoretical models. The estimated activation volume for gamma uranium seems to indicate a vacancy mechanism.The results on aluminium for both self and impurity diffusion agree quite well with Friedel's theoretical predictions [fr

  4. Singlet oxygen mediated DNA degradation by copper nanoparticles: potential towards cytotoxic effect on cancer cells

    OpenAIRE

    Sengupta Tapas K; Mandal Swadhin K; Santra Subhankar; Jose Gregor P

    2011-01-01

    Abstract The DNA degradation potential and anti-cancer activities of copper nanoparticles of 4-5 nm size are reported. A dose dependent degradation of isolated DNA molecules by copper nanoparticles through generation of singlet oxygen was observed. Singlet oxygen scavengers such as sodium azide and Tris [hydroxyl methyl] amino methane were able to prevent the DNA degradation action of copper nanoparticles confirming the involvement of activated oxygen species in the degradation process. Addit...

  5. Contribution to the study of the interfacial diffusion

    International Nuclear Information System (INIS)

    Perinet, Francois.

    1975-07-01

    The diffusion behaviour of matrix-precipitate boundaries is the same as that of interphase boundaries prepared by welding. Therefore the latter can be used to measure diffusivity along interphase boundaries. Diffusion rates of silver along copper-silver interfaces prepared by welding single crystals have been measured. The interfacial diffusion coefficients deduced through different analytical solutions of the diffusion equations, yield for the activation energy and the frequency factor values close to: Q(i)=65kcal/mole Dsub(i)sup(o) delta=100cm 3 .s -1 . These results seem to indicate that, in agreement with Bondy's and Job's previous results, the activation energies for interfacial diffusion are high. Furthermore it is shown that the misorientation between the two phases building the interface has an influence on the measured diffusion coefficients [fr

  6. The corrosion of copper in compacted clay

    Energy Technology Data Exchange (ETDEWEB)

    King, F.; Ryan, S.R.; Litke, C.D

    1997-12-01

    The uniform corrosion behaviour of copper has been investigated in the presence of compacted clay under simulated disposal vault conditions. The compacted clay is used to simulate the buffer material that would surround copper nuclear fuel waste containers in a Canadian disposal vault. The effect of the speciation of dissolved Cu has been investigated using three synthetic groundwaters of different salinity and various dissolved [O{sub 2}]. The formation of cuprous species is favoured by low [O{sub 2}] and high [C1{sup -}], with Cu(II) species formed at high [O{sub 2}] and low [C1{sup -}]. Because the Na-bentonite clay is a cation-exchange material, positively charged Cu(II) species are found to adsorb more strongly than negatively charged CuC1{sup -} complexes. The impact of the Cu speciation on four experimental parameters is reported: the corrosion rate, the interfacial [Cu] in the clay, the [Cu] profile through the clay layer, and the Cu(l):Cu(ll) ratio in the precipitated corrosion products. In agreement with previous studies, the overall rate-controlling process is believed to be the diffusion of dissolved Cu away from the corroding surface. Adsorption acts as a driving force for corrosion by immobilizing dissolved Cu. Under the conditions used in these experiments, the diffusion of dissolved O{sub 2} to the Cu surface was not rate controlling. (author)

  7. Coping with copper

    DEFF Research Database (Denmark)

    Nunes, Ines Marques; Jacquiod, Samuel Jehan Auguste; Brejnrod, Asker Daniel

    2016-01-01

    Copper has been intensively used in industry and agriculture since mid-18(th) century and is currently accumulating in soils. We investigated the diversity of potential active bacteria by 16S rRNA gene transcript amplicon sequencing in a temperate grassland soil subjected to century-long exposure...

  8. and copper(II)

    Indian Academy of Sciences (India)

    Unknown

    characterization of several imidazolate-bridged binuclear copper(II) complexes have been reported 1–17. ... of the desired complex formed were collected, washed with ethanol and dried in vacuo at room temperature. .... 16. Sigel H (ed.) 1981 Metal ions in biological system (New York: Marcel Dekker) vol 13, p. 259. 17.

  9. Regression of Copper-Deficient Heart Hypertrophy: Reduction in the Size of Hypertrophic Cardiomyocytes

    Science.gov (United States)

    Dietary copper deficiency causes cardiac hypertrophy and its transition to heart failure in a mouse model. Copper repletion results in a rapid regression of cardiac hypertrophy and prevention of heart failure. The present study was undertaken to understand dynamic changes of cardiomyocytes in the hy...

  10. Copper desorption from Gelidium algal biomass.

    Science.gov (United States)

    Vilar, Vítor J P; Botelho, Cidália M S; Boaventura, Rui A R

    2007-04-01

    Desorption of divalent copper from marine algae Gelidium sesquipedale, an algal waste (from agar extraction industry) and a composite material (the algal waste immobilized in polyacrylonitrile) was studied in a batch system. Copper ions were first adsorbed until saturation and then desorbed by HNO(3) and Na(2)EDTA solutions. Elution efficiency using HNO(3) increases as pH decreases. At pH=1, for a solid to liquid ratio S/L=4gl(-1), elution efficiency was 97%, 95% and 88%, the stoichiometric coefficient for the ionic exchange, 0.70+/-0.02, 0.73+/-0.05 and 0.76+/-0.06 and the selectivity coefficient, 0.93+/-0.07, 1.0+/-0.3 and 1.1+/-0.3, respectively, for algae Gelidium, algal waste and composite material. Complexation of copper ions by EDTA occurs in a molar proportion of 1:1 and the elution efficiency increases with EDTA concentration. For concentrations of 1.4, 0.88 and 0.57 mmoll(-1), the elution efficiency for S/L=4gl(-1), was 91%, 86% and 78%, respectively, for algae Gelidium, algal waste and composite material. The S/L ratio, in the range 1-20gl(-1), has little influence on copper recovery by using 0.1M HNO(3). Desorption kinetics was very fast for all biosorbents. Kinetic data using HNO(3) as eluant were well described by the mass transfer model, considering the average metal concentration in the solid phase and the equilibrium relationship given by the mass action law. The homogeneous diffusion coefficient varied between 1.0 x 10(-7)cm(2)s(-1) for algae Gelidium and 3.0 x 10(-7)cm(2)s(-1) for the composite material.

  11. Kurtosis as a diffuseness measure

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2016-01-01

    This study presents a kurtosis analysis of room impulse responses as a potential room diffuseness measure. In the early part of an impulse response, sound pressure samples do not constitute a Gaussian distribution due to the direct sound and strong reflections. Such deterministic reflections...... are extreme events, which prevent the pressure samples from being normally distributed, leading to a high kurtosis. As the reflections are sparser and stronger, the sound field becomes less diffuse and the kurtosis systematically increases, indicating that it can be used as a diffuseness measure. The kurtosis...... converges to zero, as the reflection overlap becomes heavier, which is an important condition for a perfect diffuse field. Two rooms are analyzed. A small rectangular room shows that a non-uniform surface absorption distribution tends to increase the kurtosis significantly. A full scale reverberation...

  12. Presenilin promotes dietary copper uptake.

    Directory of Open Access Journals (Sweden)

    Adam Southon

    Full Text Available Dietary copper is essential for multicellular organisms. Copper is redox active and required as a cofactor for enzymes such as the antioxidant Superoxide Dismutase 1 (SOD1. Copper dyshomeostasis has been implicated in Alzheimer's disease. Mutations in the presenilin genes encoding PS1 and PS2 are major causes of early-onset familial Alzheimer's disease. PS1 and PS2 are required for efficient copper uptake in mammalian systems. Here we demonstrate a conserved role for presenilin in dietary copper uptake in the fly Drosophila melanogaster. Ubiquitous RNA interference-mediated knockdown of the single Drosophila presenilin (PSN gene is lethal. However, PSN knockdown in the midgut produces viable flies. These flies have reduced copper levels and are more tolerant to excess dietary copper. Expression of a copper-responsive EYFP construct was also lower in the midgut of these larvae, indicative of reduced dietary copper uptake. SOD activity was reduced by midgut PSN knockdown, and these flies were sensitive to the superoxide-inducing chemical paraquat. These data support presenilin being needed for dietary copper uptake in the gut and so impacting on SOD activity and tolerance to oxidative stress. These results are consistent with previous studies of mammalian presenilins, supporting a conserved role for these proteins in mediating copper uptake.

  13. Diffusion coefficient in photon diffusion theory

    NARCIS (Netherlands)

    Graaff, R; Ten Bosch, JJ

    2000-01-01

    The choice of the diffusion coefficient to be used in photon diffusion theory has been a subject of discussion in recent publications on tissue optics. We compared several diffusion coefficients with the apparent diffusion coefficient from the more fundamental transport theory, D-app. Application to

  14. Diffusion of transmutation isotope in YBaCuO ceramics

    International Nuclear Information System (INIS)

    Malkovich, R.Sh.

    2005-01-01

    The diffusion of a transmutation isotope generated in YBaCuO ceramics irradiated by high-energy charged particles is mathematically analyzed. The model is based on the assumption that copper isotope atoms created in subsurface layers of ceramic grains segregate at the grain boundaries in the course of subsequent annealing and then rapidly diffuse via intergranular regions in depth of the material and penetrate into the bulk of grains [ru

  15. Copper uptake across rainbow trout gills: mechanisms of apical entry

    DEFF Research Database (Denmark)

    Grosell, Martin Hautopp; Wood, C. M.

    2002-01-01

    Copper, Homeostasis, sodium uptake, copper/sodium interactions, gill, rainbow trout, Oncorhynchus mykiss......Copper, Homeostasis, sodium uptake, copper/sodium interactions, gill, rainbow trout, Oncorhynchus mykiss...

  16. Bond-length fluctuations in the copper oxide superconductors

    CERN Document Server

    Goodenough, J B

    2003-01-01

    Superconductivity in the copper oxides occurs at a crossover from localized to itinerant electronic behaviour, a transition that is first order. A spinodal phase segregation is normally accomplished by atomic diffusion; but where it occurs at too low a temperature for atomic diffusion, it may be realized by cooperative atomic displacements. Locally cooperative, fluctuating atomic displacements may stabilize a distinguishable phase lying between a localized-electron phase and a Fermi-liquid phase; this intermediate phase exhibits quantum-critical-point behaviour with strong electron-lattice interactions making charge transport vibronic. Ordering of the bond-length fluctuations at lower temperatures would normally stabilize a charge-density wave (CDW), which suppresses superconductivity. It is argued that in the copper oxide superconductors, crossover occurs at an optimal doping concentration for the formation of ordered two-electron/two-hole bosonic bags of spin S = 0 in a matrix of localized spins; the correl...

  17. Mathematical model for simulation of the fate of copper in a marine environment

    International Nuclear Information System (INIS)

    Orlob, G.T.; Hrovat, D.; Wakeman, T.; Harrison, F.L.

    1979-01-01

    A mathematical model for the simulation of the fate of copper in a marine environment was developed. The model, which describes the kinetics of copper transformation from ionic copper to complexes with dissolved organic matter and sorption on suspended sediment, is imbedded in a two-dimensional finite element model which is capable of simulating advection and diffusion processes in natural receiving waters. Kinetic rate and equilibrium constants for the model were developed independently in laboratory experiments. A test simulation was performed under realistic conditions of slug discharge of ionic copper with the cooling water from a nuclear power station situated on the California coast. Results show that the model performed correctly under the conditions assumed. Future research and development is directed toward improving description of copper kinetics under varying environmental conditions and exploring the sensitivity of the model

  18. An analysis of copper transport in the insulation of high voltage transformers

    CERN Document Server

    Whitfield, T B

    2001-01-01

    Measurements of surface concentrations by XPS correlate well with measurements made with atomic absorption spectroscopy on solutions of extracts of the contaminated paper. The laboratory measurements have allowed determination of the diffusion coefficients and activation energy for the transport process and thus give a basis for interpretation of the diffusion profiles found in the transformer in terms of time and temperature of operation. The diffusion process is temperature dependant. The results have been used to produce long term prediction curves. Examination of the paper insulation and copper stress braiding during stripdown of a number of Current Transformers (FMK type 400kV) has revealed the presence of dark deposits. Copper foils are often interspersed within layers of paper insulation and mineral oil found in transformer windings. The dark deposits were often found in association with these foils, affecting several layers of paper in addition to the layer in contact with the copper foil. This thesis...

  19. Multilevel cycle of anthropogenic copper.

    Science.gov (United States)

    Graedel, T E; van Beers, D; Bertram, M; Fuse, K; Gordon, R B; Gritsinin, A; Kapur, A; Klee, R J; Lifset, R J; Memon, L; Rechberger, H; Spatari, S; Vexler, D

    2004-02-15

    A comprehensive contemporary cycle for stocks and flows of copper is characterized and presented, incorporating information on extraction, processing, fabrication and manufacturing, use, discard, recycling, final disposal, and dissipation. The analysis is performed on an annual basis, ca. 1994, at three discrete governmental unit levels--56 countries or country groups that together comprise essentially all global anthropogenic copper stocks and flows, nine world regions, and the planet as a whole. Cycles for all of these are presented and discussed, and a "best estimate" global copper cycle is constructed to resolve aggregation discrepancies. Among the most interesting results are (1) transformation rates and recycling rates in apparently similar national economies differ by factors of two or more (country level); (2) the discard flows that have the greatest potential for copper recycling are those with low magnitude flows but high copper concentrations--electronics, electrical equipment, and vehicles (regional level); (3) worldwide, about 53% of the copper that was discarded in various forms was recovered and reused or recycled (global level); (4) the highest rate of transfer of discarded copper to repositories is into landfills, but the annual amount of copper deposited in mine tailings is nearly as high (global level); and (5) nearly 30% of copper mining occurred merely to replace copper that was discarded. The results provide a framework for similar studies of other anthropogenic resource cycles as well as a basis for supplementary studies in resource stocks, industrial resource utilization, waste management, industrial economics, and environmental impacts.

  20. An Investigation of Low Biofouling Copper-charged Membranes

    Science.gov (United States)

    Asapu, Sunitha

    Water is essential for the survival of life on Earth, but pollutants in water can cause dangerous diseases and fatalities. The need for purified water has been increasing with increasing world population; however, natural sources of water such as rivers, lakes and streams, are progressively falling shorter and shorter of meeting water needs. The provision of clean, drinkable water to people is a key factor for the development of novel and alternative water purification technologies, such as membrane separations. Nanofiltration (NF) is a membrane separations technology that purifies water from lower quality sources, such as brackish water, seawater and wastewater. During the filtration of such sources, materials that are rejected by the membrane may accumulate on the surface of the membrane to foul it. Such materials include organic and inorganic matter, colloids, salts and microorganisms. The former four can often be controlled via pretreatment; however, the accumulation of microorganisms is more problematic to membranes. Biofouling is the accumulation and growth of microorganisms on the surface of membranes and on feed spacers. After attachment, microorganisms excrete extracellular polymeric substances (EPS), which form a matrix around the organism's outer surface as biofilm. These biofilms are detrimental and result in irreversible membrane fouling. Copper and silver ions inactivate the bacterial cells and prevent the DNA replication in microbial cells. Previous studies using copper-charged feed spacers have shown the ability of copper to control biofouling without a significant amount of copper leaching from copper-charged polypropylene (PP) feed spacers during crossflow filtration. Also, filtration using unmodified speed facers experienced almost 70% flux decline, while filtration using copper-charged feed spacers displayed only 25% flux decline. These intriguing results led to the hypothesis that the polymer chemistry could be extrapolated to produce membranes

  1. and copper(II)

    Indian Academy of Sciences (India)

    Unknown

    that the imidazolate-bridged complex is stable over the pH-range 7⋅15–10⋅0. .... copper(II) complex. The observed room temperature magnetic moments are around. 1⋅79 BM, in agreement with a one-spin (S = 1/2) system. 3.2 EPR studies .... (SK) thanks the Council of Scientific & Industrial Research, New Delhi for an.

  2. Copper Pyrimidine based MOFs

    Indian Academy of Sciences (India)

    Cl..Cu.. interactions but restricted ..Cu..N N..Cu interacations. Supramolecular isomers of Br and I are reported for the first time in this paper. [Cu2I(pdz)X2]. Figure S18. Self assembly of the simultaneous presence of tecton {Cu(sol)3X} and {Cu(pdz)(sol)2X} result in [Cu2I(pdz)X2]. 1. Table S3. Copper Pyrimidine based MOFs ...

  3. Effect of organic complexation on copper accumulation and toxicity to the estuarine red macroalga Ceramium tenuicorne: a test of the free ion activity model.

    Science.gov (United States)

    Ytreberg, Erik; Karlsson, Jenny; Hoppe, Sabina; Eklund, Britta; Ndungu, Kuria

    2011-04-01

    Current water quality criteria (WQC) regulations on copper toxicity to biota are still based on total dissolved (copper concentrations with a hardness modification for freshwaters. There are however ongoing efforts to incorporate metal speciation in WQC and toxicity regulations (such as the biotic ligand model-BLM) for copper and other metals. Here, we show that copper accumulation and growth inhibition of the Baltic macroalga Ceramium tenuicorne exposed to copper in artificial seawater at typical coastal and estuarine DOC concentrations (similar to 2-4 mg/L-C as fulvic acid) are better correlated to weakly complexed and total dissolved copper concentrations rather than the free copper concentration [Cu2+]. Our results using a combination of competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV) measurements and model calculations (using visual MINTEQ incorporating the Stockholm Humic Model) show that copper accumulation in C. tenuicorne only correlates linearly well to [Cu2+] at relatively high [Cu2+] and in the absence of fulvic acid. Thus the FIAM fails to describe copper accumulation in C. tenuicorne at copper and DOC concentrations typical of most marine waters. These results seem to indicate that at ambient total dissolved copper concentration in coastal and estuarine waters, C. tenuicorne might be able to access a sizable fraction of organically complexed copper when free copper concentration to the cell membrane is diffusion limited.

  4. Native copper as a natural analogue for copper canisters

    International Nuclear Information System (INIS)

    Marcos, N.

    1989-12-01

    This paper discusses the occurrence of native copper as found in geological formations as a stability analogue of copper canisters that are planned to be used for the disposal of spent nuclear fuel in the Finnish bedrock. A summary of several publications on native copper occurrences is presented. The present geochemical and geohydrological conditions in which copper is met with in its metallic state show that metallic copper is stable in a wide range of temperatures. At low temperatures native copper is found to be stable where groundwater has moderate pH (about 7), low Eh (< +100 mV), and low total dissolved solids, especially chloride. Microscopical and microanalytical studies were carried out on a dozen of rock samples containing native copper. The results reveal that the metal shows no significant alteration. Only the surface of copper grains is locally coated. In the oldest samples there exist small corrosion cracks; the age of the oldest samples is over 1,000 million years. A review of several Finnish groundwater studies suggests that there are places in Finland where the geohydrological conditions are favourable for native copper stability. (orig.)

  5. SITE-94. CAMEO: A model of mass-transport limited general corrosion of copper canisters

    International Nuclear Information System (INIS)

    Worgan, K.J.; Apted, M.J.

    1996-12-01

    This report describes the technical basis for the CAMEO code, which models the general, uniform corrosion of a copper canister either by transport of corrodants to the canister, or by transport of corrosion products away from the canister. According to the current Swedish concept for final disposal of spent nuclear fuels, extremely long containment times are achieved by thick (60-100 mm) copper canisters. Each canister is surrounded by a compacted bentonite buffer, located in a saturated, crystalline rock at a depth of around 500 m below ground level. Three diffusive transport-limited cases are identified for general, uniform corrosion of copper: General corrosion rate-limited by diffusive mass-transport of sulphide to the canister surface under reducing conditions; General corrosion rate-limited by diffusive mass-transport of oxygen to the canister surface under mildly oxidizing conditions; General corrosion rate-limited by diffusive mass-transport of copper chloride away from the canister surface under highly oxidizing conditions. The CAMEO code includes general corrosion models for each of the above three processes. CAMEO is based on the well-tested CALIBRE code previously developed as a finite-difference, mass-transfer analysis code for the SKI to evaluate long-term radionuclide release and transport in the near-field. A series of scoping calculations for the general, uniform corrosion of a reference copper canister are presented

  6. Unexpected role of the copper transporter ATP7A in PDGF-induced vascular smooth

    Energy Technology Data Exchange (ETDEWEB)

    Ashino, T.; Varadarajan, S.; Urao, N.; Oshikawa, J.; Chen, G. -F.; Wang, H.; Huo, Y.; Finney, L.; Vogt, S.; McKinney, R. D.; Maryon, E. B.; Kaplan, J. H.; Ushio-Fukai, M.; Fukai, T. (Biosciences Division); ( XSD); ( PSC-USR); (Univ. of Illinois at Chicago); (Univ. of Minnesota)

    2010-09-09

    Copper, an essential nutrient, has been implicated in vascular remodeling and atherosclerosis with unknown mechanism. Bioavailability of intracellular copper is regulated not only by the copper importer CTR1 (copper transporter 1) but also by the copper exporter ATP7A (Menkes ATPase), whose function is achieved through copper-dependent translocation from trans-Golgi network (TGN). Platelet-derived growth factor (PDGF) promotes vascular smooth muscle cell (VSMC) migration, a key component of neointimal formation. To determine the role of copper transporter ATP7A in PDGF-induced VSMC migration. Depletion of ATP7A inhibited VSMC migration in response to PDGF or wound scratch in a CTR1/copper-dependent manner. PDGF stimulation promoted ATP7A translocation from the TGN to lipid rafts, which localized at the leading edge, where it colocalized with PDGF receptor and Rac1, in migrating VSMCs. Mechanistically, ATP7A small interfering RNA or CTR small interfering RNA prevented PDGF-induced Rac1 translocation to the leading edge, thereby inhibiting lamellipodia formation. In addition, ATP7A depletion prevented a PDGF-induced decrease in copper level and secretory copper enzyme precursor prolysyl oxidase (Pro-LOX) in lipid raft fraction, as well as PDGF-induced increase in LOX activity. In vivo, ATP7A expression was markedly increased and copper accumulation was observed by synchrotron-based x-ray fluorescence microscopy at neointimal VSMCs in wire injury model. These findings suggest that ATP7A plays an important role in copper-dependent PDGF-stimulated VSMC migration via recruiting Rac1 to lipid rafts at the leading edge, as well as regulating LOX activity. This may contribute to neointimal formation after vascular injury. Our findings provide insight into ATP7A as a novel therapeutic target for vascular remodeling and atherosclerosis.

  7. Diffusion archeology for diffusion progression history reconstruction.

    Science.gov (United States)

    Sefer, Emre; Kingsford, Carl

    2016-11-01

    Diffusion through graphs can be used to model many real-world processes, such as the spread of diseases, social network memes, computer viruses, or water contaminants. Often, a real-world diffusion cannot be directly observed while it is occurring - perhaps it is not noticed until some time has passed, continuous monitoring is too costly, or privacy concerns limit data access. This leads to the need to reconstruct how the present state of the diffusion came to be from partial diffusion data. Here, we tackle the problem of reconstructing a diffusion history from one or more snapshots of the diffusion state. This ability can be invaluable to learn when certain computer nodes are infected or which people are the initial disease spreaders to control future diffusions. We formulate this problem over discrete-time SEIRS-type diffusion models in terms of maximum likelihood. We design methods that are based on submodularity and a novel prize-collecting dominating-set vertex cover (PCDSVC) relaxation that can identify likely diffusion steps with some provable performance guarantees. Our methods are the first to be able to reconstruct complete diffusion histories accurately in real and simulated situations. As a special case, they can also identify the initial spreaders better than the existing methods for that problem. Our results for both meme and contaminant diffusion show that the partial diffusion data problem can be overcome with proper modeling and methods, and that hidden temporal characteristics of diffusion can be predicted from limited data.

  8. Jet-printed copper metallization

    Science.gov (United States)

    Hong, Cheong Min

    Macroelectronics is a technology for making electronic circuits over very large areas at low cost. Flat panel displays, sensor arrays, and thin film solar cells are examples of macroelectronics. Crucial to the success of this new technology is the development of inexpensive electronic processes, materials, and devices. Direct printing techniques, which eliminate processing steps and save device and process materials, are the key to high volume and high throughput manufacturing. Copper metallization has been receiving increasing attention in both microelectronics and macroelectronics. Copper has high conductivity, density, melting point, heat capacity, and thermal conductivity. However, copper is also hard to dry etch. For these reasons we have developed and demonstrated a directly printed copper source/drain metallization technique and applied it to the fabrication of hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFTs). The maximum process temperature of 200°C is compatible with conventional active matrix liquid crystal display (AMLCD) technology. In this dissertation, we show the process of depositing copper films by jet printing. We discuss the preparation and the properties of the copper precursor material used in the jet printing. We survey the conversion process from copper precursor to copper under varying processing conditions. The resulting copper film is probed for its physical, electrical, and mechanical properties. To demonstrate the feasibility of the jet printing technique, we print copper source/drain contacts for a-Si:H TFTs. The photolithography-free TFT fabrication process uses the printed xerographic toner technique developed earlier in this laboratory. We show that functional TFTs can be made with printed copper source and drain contacts. The jet printing of copper contacts represents a further step toward an all-printed thin film transistor technology.

  9. Diffusion-Weighted MR Imaging of Unusual White Matter Lesion in a Patient with Menkes Disease

    International Nuclear Information System (INIS)

    Lee, Eun Shin; Ryoo, Jae Wook; Choi, Dae Seob; Cho, Jae Min; Kwon, Soo Hyun; Shin, Hee Suk

    2007-01-01

    We report here on the diffusion-weighted imaging of unusual white matter lesions in a case of Menkes disease. On the initial MR imaging, the white matter lesions were localized in the deep periventricular white matter in the absence of diffuse cortical atrophy. The lesion showed diffuse high signal on the diffusion weighted images and diffuse progression and persistent hyperintensity on the follow up imaging. Our case suggests that the white matter lesion may precede diffuse cortical atrophy in a patient with Menkes disease. Menkes disease is an X-linked disorder that's caused by impaired intracellular transport of copper. We describe here the DWI findings of unusual and progressive white matter lesions in a case of Menkes disease. Menkes disease is an X-linked recessive disorder, and it is due to an inborn error of copper metabolism. The cause of Menkes disease has been isolated to a genetic defect in copper-transporting adenosine triphosphatase, and this results in low levels of intracellular copper. It is characterized clinically by failure to thrive, retarded mental and motor development, clonic seizure and peculiarly coarse, sparse and colorless scalp hair. These clinical findings can be explained by a dysfunction of the copper-dependent enzymes

  10. Chemical vapor deposition of refractory ternary nitrides for advanced diffusion barriers

    Energy Technology Data Exchange (ETDEWEB)

    Custer, Jonathan S.; Fleming, James G.; Roherty-Osmun, Elizabeth; Smith, Paul Martin

    1998-09-22

    Refractory ternary nitride films for diffusion barriers in microelectronics have been grown using chemical vapor deposition. Thin films of titanium-silicon-nitride, tungsten-boron-nitride, and tungsten-silicon-nitride of various compositions have been deposited on 150 mm Si wafers. The microstructure of the films are either fully amorphous for the tungsten based films, or nauocrystalline TiN in an amorphous matrix for titanium-silicon-nitride. All films exhibit step coverages suitable for use in future microelectronics generations. Selected films have been tested as diffusion barriers between copper and silicon, and generally perform extremely weH. These fiIms are promising candidates for advanced diffusion barriers for microelectronics applications. The manufacturing of silicon wafers into integrated circuits uses many different process and materials. The manufacturing process is usually divided into two parts: the front end of line (FEOL) and the back end of line (BEOL). In the FEOL the individual transistors that are the heart of an integrated circuit are made on the silicon wafer. The responsibility of the BEOL is to wire all the transistors together to make a complete circuit. The transistors are fabricated in the silicon itself. The wiring is made out of metal, currently aluminum and tungsten, insulated by silicon dioxide, see Figure 1. Unfortunately, silicon will diffuse into aluminum, causing aluminum spiking of junctions, killing transistors. Similarly, during chemical vapor deposition (CVD) of tungsten from ~fj, the reactivity of the fluorine can cause "worn-holes" in the silicon, also destroying transistors. The solution to these problems is a so-called diffusion barrier, which will allow current to pass from the transistors to the wiring, but will prevent reactions between silicon and the metal.

  11. Form and toxicity of copper released into marine systems from ...

    Science.gov (United States)

    The fate and effects of pristine engineered nanomaterials (ENMs) in simplified systems have been widely studied; however, little is known about the potential release and impact of ENMs from consumer goods, especially lumber that has been treated with micronized copper. Micronized copper solutions contain copper complexes predominately in the 10-700 nm size range, and are used in lumber to prevent microbial degradation and fouling. In this work, the goal was to determine the rate, concentration, and form of copper released from commercially available pressure treated lumber samples (blocks and sawdust) exposed to an aqueous system. Lumber tested included Southern Yellow Pine (SYP) treated with micronized copper azole (MCA) at 0.96 and 2.4 Kg/m3, alkaline copper quaternary (ACQ) at 0.30 and 9.6 Kg/m3, and chromated copper arsenate (CCA) at 40 Kg/m3. Of the different chemical treatments, only MCA included nano- and micro-sized copper complexes. The experimental system included wood cubes cut from the outer 2 cm surface of the lumber or the equivalent mass (4 g) of sawdust submerged in 250 mL of media (0, 1, 10, and 30 ppt filtered natural seawater) in polyethylene bottles, and mixed on a shaker table at 120 rpm. Water samples were taken at 8 hours, and on days 1, 2, 7, 14, and 28 for the blocks and days 1, 2, 3, 7, 17, and 28 for the sawdust. Subsamples included unfiltered water (defined as 0.45 µm - filtered water for the sawdust), and water filtered through a 0.

  12. Copper Tolerance and Characterization of a Copper-Responsive Operon, copYAZ, in an M1T1 Clinical Strain of Streptococcus pyogenes.

    Science.gov (United States)

    Young, Christie A; Gordon, Lily D; Fang, Zhong; Holder, Robert C; Reid, Sean D

    2015-08-01

    Infection with Streptococcus pyogenes is associated with a breadth of clinical manifestations ranging from mild pharyngitis to severe necrotizing fasciitis. Elevated levels of intracellular copper are highly toxic to this bacterium, and thus, the microbe must tightly regulate the level of this metal ion by one or more mechanisms, which have, to date, not been clearly defined. In this study, we have identified two virulence mechanisms by which S. pyogenes protects itself against copper toxicity. We defined a set of putative genes, copY (for a regulator), copA (for a P1-type ATPase), and copZ (for a copper chaperone), whose expression is regulated by copper. Our results indicate that these genes are highly conserved among a range of clinical S. pyogenes isolates. The copY, copA, and copZ genes are induced by copper and are transcribed as a single unit. Heterologous expression assays revealed that S. pyogenes CopA can confer copper tolerance in a copper-sensitive Escherichia coli mutant by preventing the accumulation of toxic levels of copper, a finding that is consistent with a role for CopA in copper export. Evaluation of the effect of copper stress on S. pyogenes in a planktonic or biofilm state revealed that biofilms may aid in protection during initial exposure to copper. However, copper stress appears to prevent the shift from the planktonic to the biofilm state. Therefore, our results indicate that S. pyogenes may use several virulence mechanisms, including altered gene expression and a transition to and from planktonic and biofilm states, to promote survival during copper stress. Bacterial pathogens encounter multiple stressors at the host-pathogen interface. This study evaluates a virulence mechanism(s) utilized by S. pyogenes to combat copper at sites of infection. A better understanding of pathogen tolerance to stressors such as copper is necessary to determine how host-pathogen interactions impact bacterial survival during infections. These insights may

  13. EBSD Analysis of Narrow Damascene Copper Lines

    Science.gov (United States)

    Geiss, Roy H.; Read, David T.; Alers, Glenn B.; Graham, Rebekah L.

    2009-09-01

    Orientation imaging microscopy by electron backscatter diffraction (EBSD) has been used to examine grain size and crystallographic orientations of damascene Cu lines nominally 25 nm to 55 nm in width and 100 nm thick. These are the smallest structures reported to have been examined by EBSD to date. This application poses significant challenges in specimen preparation, data collection, and data analysis. Most lines were deposited on a Ta diffusion barrier, and one set had a Ti barrier. Overburden thicknesses of 120 nm, 240 nm, and 480 nm were available with the Ta diffusion barrier, but only the 120 nm overburden case was analyzed for the Ti diffusion barrier. The grain structure of the lines was predominantly bamboo. The distributions of grain lengths along individual lines had large standard deviations, ranging up to greater than the average grain size value. Print-through of overburden grains into the grain structure of the lines was evident for all lines. Large grain sizes and a strong positive correlation between line width and grain size were seen for the case of the Ta barrier layer with 120 nm overburden thickness, but not for the thicker overburden cases. Specimen surface preparation of these lines was found to be much more demanding than for larger regions of copper films such as those that have been studied previously. For some lines, prepared according to the typical state of the art, we were able to find indexable diffraction signals from less than half of the 100 μm line length.

  14. An extension of diffusion theory for thermal neutrons near boundaries

    International Nuclear Information System (INIS)

    Alvarez Rivas, J. L.

    1963-01-01

    The distribution of thermal neutron flux has been measured inside and outside copper rods of several diameters, immersed in water. It has been found that these distributions can be calculated by means of elemental diffusion theory if the value of the coefficient of diffusion is changed. this parameter is truly a diffusion coefficient, which now also depends on the diameter of the rod. Through a model an expression of this coefficient is introduced which takes account of the measurements of the author and of those reported in PIGC P/928 (1995), ANL-5872 (1959), DEGR 319 (D) (1961). This model could be extended also to plane geometry. (Author) 19 refs

  15. Nickel, copper and cobalt coalescence in copper cliff converter slag

    Directory of Open Access Journals (Sweden)

    Wolf A.

    2016-01-01

    Full Text Available The aim of this investigation is to assess the effect of various additives on coalescence of nickel, copper and cobalt from slags generated during nickel extraction. The analyzed fluxes were silica and lime while examined reductants were pig iron, ferrosilicon and copper-silicon compound. Slag was settled at the different holding temperatures for various times in conditions that simulated the industrial environment. The newly formed matte and slag were characterized by their chemical composition and morphology. Silica flux generated higher partition coefficients for nickel and copper than the addition of lime. Additives used as reducing agents had higher valuable metal recovery rates and corresponding partition coefficients than fluxes. Microstructural studies showed that slag formed after adding reductants consisted of primarily fayalite, with some minute traces of magnetite as the secondary phase. Addition of 5 wt% of pig iron, ferrosilicon and copper-silicon alloys favored the formation of a metallized matte which increased Cu, Ni and Co recoveries. Addition of copper-silicon alloys with low silicon content was efficient in copper recovery but coalescence of the other metals was low. Slag treated with the ferrosilicon facilitated the highest cobalt recovery while copper-silicon alloys with silicon content above 10 wt% resulted in high coalescence of nickel and copper, 87 % and 72 % respectively.

  16. Spectrographic determination of impurities in copper and copper oxide

    International Nuclear Information System (INIS)

    Sabato, S.F.; Lordello, A.R.

    1990-11-01

    An emission spectrographic method for the determination of Al, Bi, Ca, Cd, Cr, Fe, Ge, Mg, Mn, Mo, Ni, Pb, Sb, Si, Sn and Zn in copper and copper oxide is described. Two mixtures (Graphite and ZnO: graphite and GeO sub(2)) were used as buffers. The standard deviation lies around 10%. (author)

  17. Effects of short immersion time and cooling rates of copperizing process to the evolution of microstructures and copper behavior in the dead mild steel

    Science.gov (United States)

    Jatimurti, Wikan; Sutarsis, Cunika, Aprida Ulya

    2017-01-01

    In a dead mild steel with maximum carbon content of 0.15%, carbon does not contribute much to its strength. By adding copper as an alloying element, a balance between strength and ductility could be obtained through grain refining, solid solution, or Cu precipitation. This research aimed to analyse the changes in microstructures and copper behaviour on AISI 1006, including the phases formed, composition, and Cu dispersion. The addition of cooper was done by immersing steel into molten copper or so we called, copperizing using the principles of diffusion. Specimens were cut with 6 × 3 × 0.3 cm measurement then preheated to 900°C and melting the copper at 1100°C. Subsequently, the immersion of the specimens into molten copper varied to 5 and 7 minutes, and also varying the cooling rate to annealing, normalizing, and quenching. A series of test being conduct were optical microscope test, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), optical emission spectroscopy (OES), and X-ray diffraction (XRD). The results showed that the longer the immersion time and slower cooling rate, the more Cu diffused causing smaller grain size with the highest Cu diffused recorded was 0.277% in the copperized AISI 1006 steel with 7 minutes of immersion and was annealed. The grain size reduced to 23041.5404 µm2. The annealed specimens show ferrite phase, the normalized ones show polygonal ferrite phase, while the quenched ones show granular bainite phase. The phase formed is single phase Cu. In addition, the normalized and quenched specimens show that Cu dissolved in Fe crystal forming solid solution.

  18. Cu diffusion across a clean Si(111) surface

    CERN Document Server

    Dolbak, A E; Olshanetskij, B Z

    2001-01-01

    Cu diffusion across a clean Si(111) surface has been studied by the Auger electron spectroscopy and the low energy electron diffraction. It has been established that enhanced copper density areas with noticeable boundaries manifest themselves and a Si(111) - 5 x 5 - Cu surface phase is formed as a result of diffusion. It has been shown that the copper transport along Si(111) surface goes on according to a solid state spreading process, which is known as the unwinding carpet mechanism. The temperature dependence for the Cu diffusion coefficients D sub C sub u on the Si(111) surface is obtained and this dependence takes the form: D sub C sub u = 10 sup 4 exp(-1.9/kT) cm sup 2 /s

  19. Investigation of Copper Ammonia Leaching from Smelter Slags: Characterization, Leaching and Kinetics

    Science.gov (United States)

    Bidari, Ehsan; Aghazadeh, Valeh

    2015-10-01

    Although ammonia leaching of copper from slags has been reported generally as a part of copper slag utilization methods, but no detailed studies have been reported in the literature. In this research, we tried to investigate the effect of different parameters on ammonia leaching of copper from copper smelting slag by identifying different copper-bearing phases and following them during leaching time. Mineralogical characterization of the smelting slag (1.7 pct Cu) was done using X-ray fluorescence, X-ray diffraction, optical microscopy, diagnostic leaching tests, and scanning electron microscopy. The characterization studies indicated that main copper-bearing species are soluble copper oxides and chalcocite along with minor amount of covellite, bornite, blister copper particles, and chalcopyrite. It was also found that only approximately 0.2 pct Cu was present in the insoluble bulk silicate phases. These results suggest that approximately 88 pct of the total copper of slag could be extracted by ammonia sulfide leaching. Leaching tests were carried out and the effects of various parameters, namely pH, ammonia concentration, temperature, presence of oxygen, stirring speed, and pulp density were examined on copper leaching. The temperature and stirring speed had the most pronounced effect on the copper leaching, whereas ammonia affected the leaching yield at low concentrations of ammonia. It was found that 78 pct of Cu could be extracted within 4 hours and under optimum conditions: T = 343 K (70 °C), 2M ammonia, pH 10.5, stirring speed = 900 rpm, pulp density = 10 pct ( w s/ v). The kinetic data were analyzed with the shrinking core models, and it was found that the leaching process is controlled by both the interfacial transfer and diffusion across the product layer and the activation energy is calculated to be 49.4 kJ mol-1.

  20. Excess Entropy and Diffusivity

    Indian Academy of Sciences (India)

    First page Back Continue Last page Graphics. Excess Entropy and Diffusivity. Excess entropy scaling of diffusivity (Rosenfeld,1977). Analogous relationships also exist for viscosity and thermal conductivity.

  1. Pourbaix Diagrams for Copper in 5 m Chloride Solution

    International Nuclear Information System (INIS)

    Beverskog, Bjoern; Pettersson, Sven-Olof

    2002-12-01

    Pourbaix diagrams for the copper in 5 molal chlorine at 5-100 deg C have been calculated. Predominance diagrams for dissolved copper containing species have also been calculated. Two different total concentrations of dissolved copper, 10 -4 and 10 -6 molal, have been used in the calculations. ChIoride is the predominating chlorine species in aqueous solutions. Therefore Pourbaix diagrams for chlorine can be used to discuss the effect of chloride solutions on the corrosion behavior of a metal. Presence of chloride increases the corrosion regions of copper at the expense of the immunity and passivity regions in the Pourbaix diagrams. Copper corrodes in 5 molal chloride by formation Of CuCl 3 2- in acid and alkaline solutions. At higher potentials in acid solutions CuCl 3 2- is oxidized to CuCl 2 (aq), which at increasing potentials can form CuCI + , Cu 2+ or CuClO 3 + . Copper passivates by formation of Cu 2 O(cr), CuO(cr), or CUO 2 3 Cu(OH) 2 (s). Cu 2 O(cr) does not form at [Cu(aq)] tot = 10 -6 molal in 5 m C1-, which results in a corrosion area between the immunity and passivity areas. Copper at the anticipated repository potentials and pH corrodes at 100 deg C at [Cu(aq)] tot = 10 -4 molal and at 80-100 deg C at [Cu(aq)] tot = 10 -6 molal. Copper at the anticipated repository potentials and pH can corrode at 80 deg C at [Cu(aq)] tot = 10 -4 molal and at 50 deg C at [Cu(aq)] tot = 10 -6 molal. The bentonite clay and copper canisters in the deep repository can be considered as a 'closed' system from macroscopic point of view. The clay barrier limits both inward diffusion of oxygen and aggressive anions as well as outward diffusion of corrosion products from the canisters. Both diffusion phenomena will drive the corrosion potential into the immunity area of the Pourbaix diagram for copper. The corrosion will thereby stop by an automatic mechanism. However, this is only valid if no macro cracks occur in the clay. The auto-stop is valid for the initial, main and

  2. Pourbaix Diagrams for Copper in 5 m Chloride Solution

    Energy Technology Data Exchange (ETDEWEB)

    Beverskog, Bjoern [OECD Halden Reactor Project (Norway); Pettersson, Sven-Olof [ChemIT, Nykoeping (Sweden)

    2002-12-01

    Pourbaix diagrams for the copper in 5 molal chlorine at 5-100 deg C have been calculated. Predominance diagrams for dissolved copper containing species have also been calculated. Two different total concentrations of dissolved copper, 10{sup -4} and 10{sup -6} molal, have been used in the calculations. ChIoride is the predominating chlorine species in aqueous solutions. Therefore Pourbaix diagrams for chlorine can be used to discuss the effect of chloride solutions on the corrosion behavior of a metal. Presence of chloride increases the corrosion regions of copper at the expense of the immunity and passivity regions in the Pourbaix diagrams. Copper corrodes in 5 molal chloride by formation Of CuCl{sub 3}{sup 2-} in acid and alkaline solutions. At higher potentials in acid solutions CuCl{sub 3}{sup 2-} is oxidized to CuCl{sub 2}(aq), which at increasing potentials can form CuCI{sup +}, Cu{sup 2+} or CuClO{sub 3}{sup +}. Copper passivates by formation of Cu{sub 2}O(cr), CuO(cr), or CUO{sub 2} 3 Cu(OH){sub 2}(s). Cu{sub 2}O(cr) does not form at [Cu(aq)]{sub tot} = 10{sup -6} molal in 5 m C1-, which results in a corrosion area between the immunity and passivity areas. Copper at the anticipated repository potentials and pH corrodes at 100 deg C at [Cu(aq)]{sub tot} = 10{sup -4} molal and at 80-100 deg C at [Cu(aq)]{sub tot} = 10{sup -6} molal. Copper at the anticipated repository potentials and pH can corrode at 80 deg C at [Cu(aq)]{sub tot} = 10{sup -4} molal and at 50 deg C at [Cu(aq)]{sub tot} = 10{sup -6} molal. The bentonite clay and copper canisters in the deep repository can be considered as a 'closed' system from macroscopic point of view. The clay barrier limits both inward diffusion of oxygen and aggressive anions as well as outward diffusion of corrosion products from the canisters. Both diffusion phenomena will drive the corrosion potential into the immunity area of the Pourbaix diagram for copper. The corrosion will thereby stop by an automatic

  3. Studies of copper transport in mammalian cells using copper radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Camakaris, J.; Voskoboinik, I.; Brooks, H.; Greenough, M. [University of Melbourne, Parkville, VIC (Australia). Department of Genetics; Smith, S. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia). Radiopharmaceuticals Division; Mercer, J. [Deakin University, Clayton, VIC (Australia). Centre of Cellular and Molecular Biology

    1998-12-31

    The trace element copper poses a major problem for all organisms. It is essential as a number of vital enzymes require it. Copper deficiency can lead to neurological disorders, osteoporosis and weakening of arteries. However Cu is also highly toxic and homeostatic mechanisms have evolved to maintain Cu at levels which satisfy requirements but do not cause toxicity. Toxicity is mediated by the oxidative capacity of Cu and its ability to generate toxic free radicals. There are several acquired and inherited diseases due to either Cu toxicity or Cu deficiency. The study of these diseases facilitates identification of genes and proteins involved in copper homeostasis, and this in turn will provide rational therapeutic approaches. Using the copper radioisotopes {sup 64}Cu (t1/2 = 12.8 hr) and {sup 67}Cu (t1/2 = 61 hr) we have developed a number of systems for studying copper transport in mammalian cells. These include investigation of copper uptake, copper efflux and ligand blot assays for Cu-binding proteins. Our studies have focused on Menkes disease which is an inherited and usually lethal copper deficiency disorder in humans. We have demonstrated that the Menkes protein is directly involved as a copper efflux pump in mammalian cells. Using cells overexpressing the Menkes protein we have provided the first biochemical evidence that this functions as a Cu translocating (across the membrane) P-type ATPase (Voskoboinik et al., FEBS Letters, in press). These studies were carried out using purified plasma membrane vesicles. We are now carrying out structure- function studies on this protein using targeted mutations and assaying using the radiocopper vesicle assay. Recently we have commenced studies on the role of amyloid precursor protein (APP) in copper transport and relationship of this to Alzheimers disease

  4. Copper (II) complexes with aroylhydrazones

    Indian Academy of Sciences (India)

    Copper(II) complexes with aroylhydrazones ... The coordination chemistry of copper(II) with tridentate aroylhydrazones is briefly discussed in this article. ... EPR spectroscopy and variable temperature magnetic susceptibility measurements have been used to reveal the nature of the coordination geometry and magnetic ...

  5. The Bauschinger Effect in Copper

    DEFF Research Database (Denmark)

    Pedersen, Ole Bøcker; Brown, L .M.; Stobbs, W. M.

    1981-01-01

    A study of the Bauschinger effect in pure copper shows that by comparison with dispersion hardened copper the effect is very small and independent of temperature. This suggests that the obstacles to flow are deformable. A simple composite model based on this principle accounts for the data semi...

  6. Copper is a potent inhibitor of both the canonical and non-canonical NFκB pathways

    Science.gov (United States)

    Kenneth, Niall S; Hucks, Jr, George E; Kocab, Andrew J; McCollom, Annie L; Duckett, Colin S

    2014-01-01

    Copper is an essential trace element that plays key roles in many metabolic processes. Homeostatic regulation of intracellular copper is normally tightly controlled, but deregulated copper levels are found in numerous metabolic and neurodegenerative diseases, as well as in a range of neoplasms. There are conflicting reports regarding the exact role of copper in the regulation of NFκB-responsive genes, specifically whether copper leads to increased activation of the NFκB pathways, or downregulation. Here we show that increased intracellular levels of copper, using the ionophore clioquinol, leads to a potent inhibition of NFκB pathways, induced by multiple distinct stimuli. Addition of copper to cells inhibits ubiquitin-mediated degradation of IκBα by preventing its phoshorylation by the upstream IKK complex. Intriguingly, copper-dependent inhibition of NFκB can be reversed by the addition of the reducing agent, N-acetylcysteine (NAC). These results suggest that the oxidative properties of excess copper prevent NFκB activation by blocking IκBα destruction, and that NFκB activity should be assessed in diseases associated with copper excess. PMID:24552822

  7. Stress corrosion cracking of copper canisters

    Energy Technology Data Exchange (ETDEWEB)

    King, Fraser (Integrity Corrosion Consulting Limited (Canada)); Newman, Roger (Univ. of Toronto (Canada))

    2010-12-15

    A critical review is presented of the possibility of stress corrosion cracking (SCC) of copper canisters in a deep geological repository in the Fennoscandian Shield. Each of the four main mechanisms proposed for the SCC of pure copper are reviewed and the required conditions for cracking compared with the expected environmental and mechanical loading conditions within the repository. Other possible mechanisms are also considered, as are recent studies specifically directed towards the SCC of copper canisters. The aim of the review is to determine if and when during the evolution of the repository environment copper canisters might be susceptible to SCC. Mechanisms that require a degree of oxidation or dissolution are only possible whilst oxidant is present in the repository and then only if other environmental and mechanical loading conditions are satisfied. These constraints are found to limit the period during which the canisters could be susceptible to cracking via film rupture (slip dissolution) or tarnish rupture mechanisms to the first few years after deposition of the canisters, at which time there will be insufficient SCC agent (ammonia, acetate, or nitrite) to support cracking. During the anaerobic phase, the supply of sulphide ions to the free surface will be transport limited by diffusion through the highly compacted bentonite. Therefore, no HS. will enter the crack and cracking by either of these mechanisms during the long term anaerobic phase is not feasible. Cracking via the film-induced cleavage mechanism requires a surface film of specific properties, most often associated with a nano porous structure. Slow rates of dissolution characteristic of processes in the repository will tend to coarsen any nano porous layer. Under some circumstances, a cuprous oxide film could support film-induced cleavage, but there is no evidence that this mechanism would operate in the presence of sulphide during the long-term anaerobic period because copper sulphide

  8. Stress corrosion cracking of copper canisters

    International Nuclear Information System (INIS)

    King, Fraser; Newman, Roger

    2010-12-01

    A critical review is presented of the possibility of stress corrosion cracking (SCC) of copper canisters in a deep geological repository in the Fennoscandian Shield. Each of the four main mechanisms proposed for the SCC of pure copper are reviewed and the required conditions for cracking compared with the expected environmental and mechanical loading conditions within the repository. Other possible mechanisms are also considered, as are recent studies specifically directed towards the SCC of copper canisters. The aim of the review is to determine if and when during the evolution of the repository environment copper canisters might be susceptible to SCC. Mechanisms that require a degree of oxidation or dissolution are only possible whilst oxidant is present in the repository and then only if other environmental and mechanical loading conditions are satisfied. These constraints are found to limit the period during which the canisters could be susceptible to cracking via film rupture (slip dissolution) or tarnish rupture mechanisms to the first few years after deposition of the canisters, at which time there will be insufficient SCC agent (ammonia, acetate, or nitrite) to support cracking. During the anaerobic phase, the supply of sulphide ions to the free surface will be transport limited by diffusion through the highly compacted bentonite. Therefore, no HS. will enter the crack and cracking by either of these mechanisms during the long term anaerobic phase is not feasible. Cracking via the film-induced cleavage mechanism requires a surface film of specific properties, most often associated with a nano porous structure. Slow rates of dissolution characteristic of processes in the repository will tend to coarsen any nano porous layer. Under some circumstances, a cuprous oxide film could support film-induced cleavage, but there is no evidence that this mechanism would operate in the presence of sulphide during the long-term anaerobic period because copper sulphide

  9. Copper: From neurotransmission to neuroproteostasis

    Directory of Open Access Journals (Sweden)

    Carlos M Opazo

    2014-07-01

    Full Text Available Copper is critical for the Central Nervous System (CNS development and function. In particular, different studies have shown the effect of copper at brain synapses, where it inhibits Long Term Potentation (LTP and receptor pharmacology. Paradoxically, according to recent studies copper is required for a normal LTP response. Copper is released at the synaptic cleft, where it blocks glutamate receptors, which explain its blocking effects on excitatory neurotransmission. Our results indicate that copper also enhances neurotransmission through the accumulation of PSD95 protein, which increase the levels of AMPA receptors located at the plasma membrane of the post-synaptic density. Thus, our findings represent a novel mechanism for the action of copper, which may have implications for the neurophysiology and neuropathology of the CNS. These data indicate that synaptic configuration is sensitive to transient changes in transition metal homeostasis. Our results suggest that copper increases GluA1 subunit levels of the AMPA receptor through the anchorage of AMPA receptors to the plasma membrane as a result of PSD-95 accumulation. Here, we will review the role of copper on neurotransmission of CNS neurons. In addition, we will discuss the potential mechanisms by which copper could modulate neuronal proteostasis (neuroproteostasis in the CNS with focus in the Ubiquitin Proteasome System, which is particularly relevant to neurological disorders such Alzheimer’s disease (AD where copper and protein dyshomeostasis may contribute to neurodegeneration. An understanding of these mechanisms may ultimately lead to the development of novel therapeutic approaches to control metal and synaptic alterations observed in AD patients.

  10. Thin films of copper oxide and copper grown by atomic layer deposition for applications in metallization systems of microelectronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Waechtler, Thomas

    2010-05-25

    Copper-based multi-level metallization systems in today's ultralarge-scale integrated electronic circuits require the fabrication of diffusion barriers and conductive seed layers for the electrochemical metal deposition. Such films of only several nanometers in thickness have to be deposited void-free and conformal in patterned dielectrics. The envisaged further reduction of the geometric dimensions of the interconnect system calls for coating techniques that circumvent the drawbacks of the well-established physical vapor deposition. The atomic layer deposition method (ALD) allows depositing films on the nanometer scale conformally both on three-dimensional objects as well as on large-area substrates. The present work therefore is concerned with the development of an ALD process to grow copper oxide films based on the metal-organic precursor bis(trin- butylphosphane)copper(I)acetylacetonate [({sup n}Bu{sub 3}P){sub 2}Cu(acac)]. This liquid, non-fluorinated {beta}-diketonate is brought to react with a mixture of water vapor and oxygen at temperatures from 100 to 160 C. Typical ALD-like growth behavior arises between 100 and 130 C, depending on the respective substrate used. On tantalum nitride and silicon dioxide substrates, smooth films and selfsaturating film growth, typical for ALD, are obtained. On ruthenium substrates, positive deposition results are obtained as well. However, a considerable intermixing of the ALD copper oxide with the underlying films takes place. Tantalum substrates lead to a fast self-decomposition of the copper precursor. As a consequence, isolated nuclei or larger particles are always obtained together with continuous films. The copper oxide films grown by ALD can be reduced to copper by vapor-phase processes. If formic acid is used as the reducing agent, these processes can already be carried out at similar temperatures as the ALD, so that agglomeration of the films is largely avoided. Also for an integration with subsequent

  11. Diffusion bonding as joining technique for fusion reactor components

    Energy Technology Data Exchange (ETDEWEB)

    Ceccotti, G.C.; Magnoli, L.

    1992-11-01

    The development of joining techniques for fusion reactor divertors has been undertaken at ENEA (Italian Agency for Energy, New Technologies and the Environment) IFEC Saluggia. Joints were made by the diffusion bonding technique between graphite composite material with DS copper and with molybdenum TZM alloy, respectively. The inter-layers, when necessary, were obtained by metallization with an electronic gun. The same technique is employed in joining Be/SS, DS copper/Be, TZM/Be and graphite/Be for the first wall or plasma facing components of fusion reactors. In this case, a suitable inter-layer material can avoid the problems occuring with the more traditional brazing processes.

  12. Diffusion in solids

    International Nuclear Information System (INIS)

    Tiwari, G.P.; Kale, G.B.; Patil, R.V.

    1999-01-01

    The article presents a brief survey of process of diffusion in solids. It is emphasised that the essence of diffusion is the mass transfer through the atomic jumps. To begin with formal equations for diffusion coefficient are presented. This is followed by discussions on mechanisms of diffusion. Except for solutes which form interstitial solid solution, diffusion in majority of cases is mediated through exchange of sites between an atom and its neighbouring vacancy. Various vacancy parameters such as activation volume, correlation factor, mass effect etc are discussed and their role in establishing the mode of diffusion is delineated. The contribution of dislocations and grain boundaries in diffusion process is brought out. The experimental determination of different types of diffusion coefficients are described. Finally, the pervasive nature of diffusion process in number of commercial processes is outlined to show the importance of diffusion studies in materials science and technology. (author)

  13. Radiation induced segregation and point defects in binary copper alloys

    International Nuclear Information System (INIS)

    Monteiro, W.A.

    1984-01-01

    Considerable progress, both theoretical and experimental, has been made in establishing and understanding the influence of factors such as temperature, time, displacement rate dependence and the effect of initial solute misfit on radiation induced solute diffusion and segregation. During irradiation, the composition of the alloy changes locally, due to defect flux driven non-equilibrium segregation near sinks such as voids, external surfaces and grain boundaries. This change in composition could influence properties and phenomena such as ductility, corrosion resistance, stress corrosion cracking, sputtering and blistering of materials used in thermo-nuclear reactors. In this work, the effect of 1 MeV electron irradiation on the initiation and development of segregation and defect diffusion in binary copper alloys has been studied in situ, with the aid of a high voltage electron microscope. The binary copper alloys had Be, Pt and Sn as alloying elements which had atomic radii less than, similar and greater than that of copper, respectively. It has been observed that in a wide irradiation temperature range, stabilization and growth of dislocation loops took place in Cu-Sn and Cu-Pt alloys. Whereas in the Cu-Be alloy, radiation induced precipitates formed and transformed to the stable γ phase. (Author) [pt

  14. Thermal characterization and properties of a copper-diamond composite

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Pin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Chavez, Thomas P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); DiAntonio, Christopher Brian [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Coker, Eric Nicholas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    The thermal properties of a commercial copper-diamond composite were measured from below -50°C to above 200°C. The results of thermal expansion, heat capacity, and thermal diffusivity were reported. These data were used to calculate the thermal conductivity of the composite as a function of temperature in the thickness direction. These results are compared with estimated values based on a simple mixing rule and the temperature dependence of these physical properties is represented by curve fitting equations. These fitting equations can be used for thermal modeling of practical devices/systems at their operation temperatures. The results of the mixing rule showed a consistent correlation between the amount of copper and diamond in the composite, based on density, thermal expansion, and heat capacity measurements. However, there was a disparity between measured and estimated thermal diffusivity and thermal conductivity. These discrepancies can be caused by many intrinsic material issues such as lattice defects and impurities, but the dominant factor is attributed to the large uncertainty of the interfacial thermal conductance between diamond and copper.

  15. Diffusion archeology for diffusion progression history reconstruction

    OpenAIRE

    Sefer, Emre; Kingsford, Carl

    2015-01-01

    Diffusion through graphs can be used to model many real-world processes, such as the spread of diseases, social network memes, computer viruses, or water contaminants. Often, a real-world diffusion cannot be directly observed while it is occurring — perhaps it is not noticed until some time has passed, continuous monitoring is too costly, or privacy concerns limit data access. This leads to the need to reconstruct how the present state of the diffusion came to be from partial d...

  16. Copper uptake and retention in liver parenchymal cells isolated from nutritionally copper-deficient rats

    NARCIS (Netherlands)

    Berg, G.J. van den; Goeij, J.J.M. de; Bock, I.; Gijbels, M.J.J.; Brouwer, A.; Lei, K.Y.; Hendruiks, H.F.J.

    1991-01-01

    Copper uptake and retention were studied in primary cultures of liver parenchymal cells isolated from copper-deficient rats. Male Sprague-Dawley rats were fed a copper-deficient diet (< 1 mg Cu/kg) for 10 wk. Copper-deficient rats were characterized by low copper concentrations in plasma and liver,

  17. Role of copper in photochemical damage to hair.

    Science.gov (United States)

    Marsh, J M; Iveson, R; Flagler, M J; Davis, M G; Newland, A B; Greis, K D; Sun, Y; Chaudhary, T; Aistrup, E R

    2014-02-01

    The objective of this work was to identify whether low levels of redox metals such as copper will accelerate damage to hair on exposure to UV irradiation and whether this damage can be prevented. The methods used were proteomics to measure the protein damage via protein loss after different periods of exposure and mass spectroscopy methods to identify specific marker peptides that are specifically created by this type of damage. In this work, we have developed new insights into the mechanism of UV damage using these proteomic methods. A marker fragment in the hair protein loss extract was identified (m/z = 1279) that is unique to UV exposure and increases with time of UV exposure. We have also identified for the first time in hair the role of exogenous copper in increasing UV damage both in terms of total protein degradation and also increased formation of the marker fragment and proposed a mechanism of action. It has been demonstrated that shampoo treatment containing a chelant such as N,N'-ethylenediamine disuccinic acid (EDDS) reduced copper accumulation in hair. This work provides evidence for the role of copper in UV-induced damage to hair and strategies to reduce copper levels in hair using a chelant such as EDDS. © 2013 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  18. The anodization synthesis of copper oxide nanosheet arrays and their photoelectrochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Xia [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Zheng, Hongmei [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Key Laboratory of Advanced Functional Materials and Devices of Anhui Province, Hefei 230009 (China); Xu, Guangqing, E-mail: gqxu1979@hfut.edu.cn [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Key Laboratory of Advanced Functional Materials and Devices of Anhui Province, Hefei 230009 (China); Zhao, Jiebo [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Cui, Lihua [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); School of Materials Science and Engineering, Beifang University of Nationalities, Yinchuan 750021 (China); Cui, Jiewu; Qin, Yongqiang; Wang, Yan [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Zhang, Yong [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Key Laboratory of Advanced Functional Materials and Devices of Anhui Province, Hefei 230009 (China); Wu, Yucheng, E-mail: ycwu@hfut.edu.cn [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Key Laboratory of Advanced Functional Materials and Devices of Anhui Province, Hefei 230009 (China)

    2017-08-01

    Graphical abstract: Current-time and potential-time curves of the copper foil anodization process, CV of copper substrate in anodization solution and SEM morphologies of anodization products on Cu substrates obtained at different time. - Highlights: • Copper oxides nanosheet arrays were achieved via anodization method. • The growth mechanisms of the copper anodization process were studied. • Photoelectrochemical performances of copper oxides NSAs were studied. - Abstract: We studied the growth of copper oxide nanosheet arrays on copper foil via a simple anodization method. The structures, morphologies, and elemental compositions of the specimens were characterized with an X-ray diffractometer, scanning electron microscope, high resolution transmission electron microscope, and X-ray photoelectron spectrometer. The copper oxide (Cu{sub 2}O and CuO) nanosheet arrays were comprised of 30-nm-thick nanosheets that stand vertically on the Cu substrate. The anodizing parameters, such as the current density, temperature, and polyethylene glycol concentration, were optimized to obtain the regular nanosheet arrays. The optical absorption properties of the anodized products were evaluated using a diffuse reflectance spectrometer, and broad and strong optical absorption bands arising from the UV to visible region were observed. The photoelectrochemical performance of the nanosheet arrays was measured with chronoamperometry and cyclic voltammetry on an electrochemical workstation equipped with a Xe lamp (wavelength >400 nm). A negative photocurrent was obtained due to the p-type semiconductor of the copper oxides. The copper oxide nanosheet arrays achieve the highest photocurrent of 0.4 mA/cm{sup 2} at the current density of 1.0 A/dm{sup 2}, temperature of 70 °C, and polyethylene glycol concentration of 0.5 g/L.

  19. Efficacy of copper sulfate hoof baths against digital dermatitis- Where is the evidence?

    DEFF Research Database (Denmark)

    Thomsen, Peter T.

    2015-01-01

    Digital dermatitis is a major problem in modern dairy production because of decreased animal welfare and financial losses. Individual cow treatments are often seen as too time consuming by farmers, and walk-through hoof baths have therefore been used extensively to control digital dermatitis....... For decades, copper sulfate hoof baths have been used to treat and prevent digital dermatitis. Copper sulfate has been referred to as the industry gold standard when it comes to hoof-bath chemicals. In several scientific studies testing the efficacy of other hoof-care products, copper sulfate has been used......, the frequent claim that copper sulfate is widely reported to be effective is supported by little scientific evidence. Well-designed clinical trials evaluating the effect of copper sulfate against digital dermatitis compared with a negative control are needed. Until such studies have been made, the efficacy...

  20. Singlet oxygen mediated DNA degradation by copper nanoparticles: potential towards cytotoxic effect on cancer cells

    Directory of Open Access Journals (Sweden)

    Sengupta Tapas K

    2011-03-01

    Full Text Available Abstract The DNA degradation potential and anti-cancer activities of copper nanoparticles of 4-5 nm size are reported. A dose dependent degradation of isolated DNA molecules by copper nanoparticles through generation of singlet oxygen was observed. Singlet oxygen scavengers such as sodium azide and Tris [hydroxyl methyl] amino methane were able to prevent the DNA degradation action of copper nanoparticles confirming the involvement of activated oxygen species in the degradation process. Additionally, it was observed that the copper nanoparticles are able to exert cytotoxic effect towards U937 and Hela cells of human histiocytic lymphoma and human cervical cancer origins, respectively by inducing apoptosis. The growth characteristics of U937 and Hela cells were studied applying various concentrations of the copper nanoparticles.

  1. Singlet oxygen mediated DNA degradation by copper nanoparticles: potential towards cytotoxic effect on cancer cells.

    Science.gov (United States)

    Jose, Gregor P; Santra, Subhankar; Mandal, Swadhin K; Sengupta, Tapas K

    2011-03-25

    The DNA degradation potential and anti-cancer activities of copper nanoparticles of 4-5 nm size are reported. A dose dependent degradation of isolated DNA molecules by copper nanoparticles through generation of singlet oxygen was observed. Singlet oxygen scavengers such as sodium azide and Tris [hydroxyl methyl] amino methane were able to prevent the DNA degradation action of copper nanoparticles confirming the involvement of activated oxygen species in the degradation process. Additionally, it was observed that the copper nanoparticles are able to exert cytotoxic effect towards U937 and Hela cells of human histiocytic lymphoma and human cervical cancer origins, respectively by inducing apoptosis. The growth characteristics of U937 and Hela cells were studied applying various concentrations of the copper nanoparticles.

  2. Copper complexes as 'radiation recovery' agents

    International Nuclear Information System (INIS)

    Sorenson, J.R.J.

    1989-01-01

    Copper and its compounds have been used for their remedial effects since the beginning of recorded history. As early as 3000 BC the Egyptians used copper as an antiseptic for healing wounds and to sterilise drinking water; and later, ca 1550 BC, the Ebers Papyrus reports the use of copper acetate, copper sulphate and pulverised metallic copper for the treatment of eye infections. These historical uses of copper and its compounds are particularly interesting in the light of modern evidence concerning the use of certain copper complexes for the treatment of radiation sickness and more recently as an adjunct to radiotherapy for cancer patients. (author)

  3. NID Copper Sample Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kouzes, Richard T.; Zhu, Zihua

    2011-09-12

    The current focal point of the nuclear physics program at PNNL is the MAJORANA DEMONSTRATOR, and the follow-on Tonne-Scale experiment, a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay (0νββ). This experiment requires the use of germanium isotopically enriched in 76Ge. The MAJORANA DEMONSTRATOR is a DOE and NSF funded project with a major science impact. The DEMONSTRATOR will utilize 76Ge from Russia, but for the Tonne-Scale experiment it is hoped that an alternate technology, possibly one under development at Nonlinear Ion Dynamics (NID), will be a viable, US-based, lower-cost source of separated material. Samples of separated material from NID require analysis to determine the isotopic distribution and impurities. DOE is funding NID through an SBIR grant for development of their separation technology for application to the Tonne-Scale experiment. The Environmental Molecular Sciences facility (EMSL), a DOE user facility at PNNL, has the required mass spectroscopy instruments for making isotopic measurements that are essential to the quality assurance for the MAJORANA DEMONSTRATOR and for the development of the future separation technology required for the Tonne-Scale experiment. A sample of isotopically separated copper was provided by NID to PNNL in January 2011 for isotopic analysis as a test of the NID technology. The results of that analysis are reported here. A second sample of isotopically separated copper was provided by NID to PNNL in August 2011 for isotopic analysis as a test of the NID technology. The results of that analysis are also reported here.

  4. Influence of sulfide concentration on the corrosion behavior of pure copper in synthetic seawater

    International Nuclear Information System (INIS)

    Taniguchi, Naoki; Kawasaki, Manabu

    2008-01-01

    Corrosion rate and stress corrosion cracking (SCC) behavior of pure copper under anaerobic conditions were studied by immersion tests and slow strain rate tests (SSRT) in synthetic seawater containing Na 2 S. The corrosion rate was increased with sulfide concentration both in simple saline solution and in bentnite-sand mixture. The results of SSRT showed that copper was susceptible to intergranular attack; selective dissolution at lower sulfide concentration (less than 0.005 M) and SCC at higher sulfide concentration (0.01 M). It was expected that if the sulfide concentration in groundwater is less than 0.001 M, pure copper is possible to exhibit superior corrosion resistance under anaerobic condition evident by very low corrosion rates and immunity to SCC. In such a low sulfide environment, copper overpack has the potential to achieve super-long lifetimes exceeding several tens of thousands years according to long-term simulations of corrosion based on diffusion of sulfide in buffer material

  5. Gallium and copper radiopharmaceutical chemistry

    International Nuclear Information System (INIS)

    Green, M.A.

    1991-01-01

    Gallium and copper radionuclides have a long history of use in nuclear medicine. Table 1 presents the nuclear properties of several gallium and copper isotopes that either are used in the routine practice of clinical nuclear medicine or exhibit particular characteristics that might make them useful in diagnostic or therapeutic medicine. This paper will provide some historic perspective along with an overview of some current research directions in gallium and copper radiopharmaceutical chemistry. A more extensive review of gallium radiopharmaceutical chemistry has recently appeared and can be consulted for a more in-depth treatment of this topic

  6. Processing and performance of reactively sputtered titanium silicon nitride liners in copper metallization

    Science.gov (United States)

    Mirza, Jawid Majid

    Titanium silicon nitride (TiSiN) is a potential candidate for diffusion barrier applications in the advanced copper metallization schemes. This thesis focuses on the process development and optimization of reactively sputtered TiSiN films using statistically valid "design of experiment" (DOE) approach and testing the copper diffusion performance of TiSiN films. The design of experiment (DOE) approach showed that the nitrogen and DC target power had the most influence over the composition and resistivity of reactively sputtered TiSiN films. Thermal diffusion barrier performance of reactively sputtered TiSiN films against copper diffusion was tested as a function of the composition of reactively sputtered TiSiN films. Rutherford backscattering spectrometry (RBS) analysis of Cu (100 nm)/TiSiN (10 nm)/Si stacks annealed at 400°C temperatures indicated that TiSiN films deposited by physical vapor deposition (PVD) technique withstood this thermal treatment for 30 minutes. The situation was drastically changed when the Cu (100 nm)/TiSiN (10 nm)/Si film stacks were annealed at 500°C or higher temperatures for 30 minutes. All of the PVD TiSiN films tested (independent of their composition) showed copper diffusion through the barrier as detected by RBS. Secco etch method was used to confirm the findings of RBS studies. It was found that the PVD TiSiN films with at least 5--10 atomic percent of nitrogen acted as a good diffusion barrier against thermal diffusion of copper 400°C for 30 minutes anneal. However, 10 nm thick PVD TiSi film failed, even at a temperature 400°C for 30 minutes anneal. All of the PVD TiSiN films (independent of composition) annealed at 500°C or higher temperatures for 30 minutes, showed Secco etch pits in the silicon substrate. These etch pits indicate copper diffusion through the liner material. Thus nitrogen concentration of at least 5--10 atomic percent improved the barrier stability of reactively sputtered TiSiN films, as determined by Secco

  7. Antimicrobial Effect of Copper Oxide Nanoparticles on Some Oral Bacteria and Candida Species

    Directory of Open Access Journals (Sweden)

    Amiri M

    2017-03-01

    Full Text Available Statement of Problem: Acid producing bacteria including Streptococcus mutans and lactobacilli cause tooth demineralization and lead to tooth decay. Also, oral colonization of the species of Candida has been reported in many studies that are resistant to antifungal agents. Objectives: In this study, antibacterial and antifungal effects of nano-CuO were studied against some oral bacteria and yeast fungi. Materials and Methods: The minimum inhibitory concentrations (MICs of copper oxide nanoparticles (CuO NPs for oral bacterial and fungal test strains were determined in 96-well microtiter plate technique. The agar diffusion test (ADT was employed to assess the antifungal properties of nystatin. Results: The MIC50 value of CuO NPs was determined at the range of 1–10 µg/ml for S. mutans, < 1 µg/ml for L. acidophilus, and 10 µg/ml for L. casei. Higher concentrations of CuO NPs (100-1000 µg/ml were effective on the bacterial cell growth, resulting in 100% reduction in the optical density in TSB medium. The cells of Candida albicans, C. krusei and C. glabrata were treated with CuO NPs and the results showed a decrease in fungal growth at a concentration of 1-1000 µg/ml in TSB medium. The MIC50 value of CuO NPs was determined 1000 µg/ml for three species of Candida. The diameter of growth inhibition zones of 1100 µg/ml nystatin was obtained 15-21 mm for clinical isolates of three species of Candida. Conclusions: With respect to the potential bactericidal activity of CuO NPs on various cariogenic bacteria examined in this study, these NPs could be introduce as a candidate control agent for preventing dental caries or dental infections. In our study, on the other hand, Nano copper oxide had a weak effect on the candida species.

  8. Comparative study on copper leaching from waste printed circuit boards by typical ionic liquid acids.

    Science.gov (United States)

    Chen, Mengjun; Huang, Jinxiu; Ogunseitan, Oladele A; Zhu, Nengming; Wang, Yan-min

    2015-07-01

    Waste printed circuit boards (WPCBs) are attracting increasing concerns because the recovery of its content of valuable metallic resources is hampered by the presence of hazardous substances. In this study, we used ionic liquids (IL) to leach copper from WPCBs. [BSO3HPy]OTf, [BSO3HMIm]OTf, [BSO4HPy]HSO4, [BSO4HMim]HSO4 and [MIm]HSO4 were selected. Factors that affect copper leaching rate were investigated in detail and their leaching kinetics were also examined with the comparison of [Bmim]HSO4. The results showed that all six IL acids could successfully leach copper out, with near 100% recovery. WPCB particle size and leaching time had similar influences on copper leaching performance, while IL acid concentration, hydrogen peroxide addition, solid to liquid ratio, temperature, showed different influences. Moreover, IL acid with HSO4(-) was more efficient than IL acid with CF3SO3(-). These six IL acids indicate a similar behavior with common inorganic acids, except temperature since copper leaching rate of some IL acids decreases with its increase. The results of leaching kinetics studies showed that diffusion plays a more important role than surface reaction, whereas copper leaching by inorganic acids is usually controlled by surface reaction. This innovation provides a new option for recovering valuable materials such as copper from WPCBs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Spin-diffusions and diffusive molecular dynamics

    Science.gov (United States)

    Farmer, Brittan; Luskin, Mitchell; Plecháč, Petr; Simpson, Gideon

    2017-12-01

    Metastable configurations in condensed matter typically fluctuate about local energy minima at the femtosecond time scale before transitioning between local minima after nanoseconds or microseconds. This vast scale separation limits the applicability of classical molecular dynamics (MD) methods and has spurned the development of a host of approximate algorithms. One recently proposed method is diffusive MD which aims at integrating a system of ordinary differential equations describing the likelihood of occupancy by one of two species, in the case of a binary alloy, while quasistatically evolving the locations of the atoms. While diffusive MD has shown itself to be efficient and provide agreement with observations, it is fundamentally a model, with unclear connections to classical MD. In this work, we formulate a spin-diffusion stochastic process and show how it can be connected to diffusive MD. The spin-diffusion model couples a classical overdamped Langevin equation to a kinetic Monte Carlo model for exchange amongst the species of a binary alloy. Under suitable assumptions and approximations, spin-diffusion can be shown to lead to diffusive MD type models. The key assumptions and approximations include a well-defined time scale separation, a choice of spin-exchange rates, a low temperature approximation, and a mean field type approximation. We derive several models from different assumptions and show their relationship to diffusive MD. Differences and similarities amongst the models are explored in a simple test problem.

  10. Microfabricated diffusion source

    Science.gov (United States)

    Oborny, Michael C [Albuquerque, NM; Frye-Mason, Gregory C [Cedar Crest, NM; Manginell, Ronald P [Albuquerque, NM

    2008-07-15

    A microfabricated diffusion source to provide for a controlled diffusion rate of a vapor comprises a porous reservoir formed in a substrate that can be filled with a liquid, a headspace cavity for evaporation of the vapor therein, a diffusion channel to provide a controlled diffusion of the vapor, and an outlet to release the vapor into a gas stream. The microfabricated diffusion source can provide a calibration standard for a microanalytical system. The microanalytical system with an integral diffusion source can be fabricated with microelectromechanical systems technologies.

  11. Selective synthesis of ternary copper-antimony sulfide nanocrystals.

    Science.gov (United States)

    Xu, Dongying; Shen, Shuling; Zhang, Yejun; Gu, Hongwei; Wang, Qiangbin

    2013-11-18

    Ternary copper-antimony sulfide nanocrystals (CAS NCs) have attracted increasing attention in photovoltaics and photoelectric nanodevices due to their tunable band gaps in the near-IR regime. Although much progress in the synthesis of CAS NCs has been achieved, the selective synthesis of CAS NCs with controllable morphologies and compositions is preliminary: in particular, a facile method is still in demand. In this work, we have successfully selectively synthesized high-quality CAS NCs with diverse morphologies, compositions, and band gaps, including rectangular CuSbS2 nanosheets (NSs), trigonal-pyramidal Cu12Sb4S13 NCs, and rhombic Cu3SbS3 NSs, by cothermodecomposition of copper diethyldithiocarbamate trihydrate (Cu(Ddtc)2) and antimony diethyldithiocarbamate trihydrate (Sb(Ddtc)3). The direct and indirect band gaps of the obtained CAS NCs were systematically studied by performing Kubelka-Munk transformations of their solid-state diffuse reflectance spectra.

  12. Copper tailings in stucco mortars

    Directory of Open Access Journals (Sweden)

    Osvaldo Pavez

    Full Text Available Abstract This investigation addressed the evaluation of the use of copper tailings in the construction industry in order to reduce the impact on the environment. The evaluation was performed by a technical comparison between stucco mortars prepared with crushed conventional sand and with copper tailings sand. The best results were achieved with the stucco mortars containing tailings. The tailings presented a fine particles size distribution curve different from that suggested by the standard. The values of compressive strength, retentivity, and adherence in the stucco mortars prepared with copper tailings were much higher than those obtained with crushed sand. According to the results from this study, it can be concluded that the preparation of stucco mortars using copper tailings replacing conventional sand is a technically feasible alternative for the construction industry, presenting the benefit of mitigating the impact of disposal to the environment.

  13. Hereditary iron and copper deposition

    DEFF Research Database (Denmark)

    Aaseth, Jan; Flaten, Trond Peder; Andersen, Ole

    2007-01-01

    Hereditary deposition of iron (primary haemochromatosis) or copper (Wilson's disease) are autosomal recessive metabolic disease characterized by progressive liver pathology and subsequent involvement of various other organs. The prevalence of primary haemochromatosis is approximately 0.5%, about...

  14. Effects of processing conditions and ambient environment on the microstructure and fracture strength of copper/niobium/copper interlayer joints for alumina

    Energy Technology Data Exchange (ETDEWEB)

    Marks, Robert Alan [Univ. of California, Berkeley, CA (United States)

    1999-12-01

    Partial transient liquid phase (PTLP) bonding is a technique which can be used to join ceramics with metals and is used to form niobium-based joints for alumina. The principal advantage to PTLP bonding is that it enables refractory joints to be fabricated at temperatures below those typically required by solid state diffusion bonding. A thorough review of the important parameters (chemical compatibility, thermal expansion match, sufficient wettability of the liquid phase on the solid phases) in choosing a joining material for ceramics by the PTLP method is provided. As in conventional PTLP joining, the current study uses thin (=3 μm) copper layers sandwiched between the alumina (bulk) and niobium (127 μm). However, unlike the case of copper/nickel/copper obium is limited. Consequently, the copper is not entirely dissolved in the process, resulting in a two phase (copper-rich and niobium-rich phases) microstructure. Different processing conditions (temperature and applied load) result in different morphologies of the copper-rich and niobium-rich phases at the interface. These different microstructures exhibit distinct strength characteristics. Extended annealing of as-processed joints can influence the strengths differently depending on the ambient partial oxygen pressure at the annealing temperature. The focus of this work is to correlate processing conditions, microstructure, and resulting joint strength. Under optimum processing conditions (1400°C, 2.2 MPa), joints with strengths in excess of 200 MPa at 1200°C are fabricated.

  15. Copper atomic-scale transistors

    Directory of Open Access Journals (Sweden)

    Fangqing Xie

    2017-03-01

    Full Text Available We investigated copper as a working material for metallic atomic-scale transistors and confirmed that copper atomic-scale transistors can be fabricated and operated electrochemically in a copper electrolyte (CuSO4 + H2SO4 in bi-distilled water under ambient conditions with three microelectrodes (source, drain and gate. The electrochemical switching-on potential of the atomic-scale transistor is below 350 mV, and the switching-off potential is between 0 and −170 mV. The switching-on current is above 1 μA, which is compatible with semiconductor transistor devices. Both sign and amplitude of the voltage applied across the source and drain electrodes (Ubias influence the switching rate of the transistor and the copper deposition on the electrodes, and correspondingly shift the electrochemical operation potential. The copper atomic-scale transistors can be switched using a function generator without a computer-controlled feedback switching mechanism. The copper atomic-scale transistors, with only one or two atoms at the narrowest constriction, were realized to switch between 0 and 1G0 (G0 = 2e2/h; with e being the electron charge, and h being Planck’s constant or 2G0 by the function generator. The switching rate can reach up to 10 Hz. The copper atomic-scale transistor demonstrates volatile/non-volatile dual functionalities. Such an optimal merging of the logic with memory may open a perspective for processor-in-memory and logic-in-memory architectures, using copper as an alternative working material besides silver for fully metallic atomic-scale transistors.

  16. The copper deposits of Michigan

    Science.gov (United States)

    Butler, B.S.; Burbank, W.S.

    1929-01-01

    The copper district of Keweenaw Point, in the northern peninsula of Michigan, is the second largest producer of copper in the world.  The output of the district since 1845 has been more than 7,500,000,000 pounds and showed a rather steady and consistent increase from the beginning of production to the end of the World War in 1918, since which there has been a marked decrease.

  17. Atmospheric corrosion effects on copper

    International Nuclear Information System (INIS)

    Franey, J.P.

    1985-01-01

    Studies have been performed on the naturally formed patina on various copper samples. Samples have been obtained from structures at AT and T Bell Laboratories, Murray Hill, NJ (40,2,1 and <1 yr) and the Statue of Liberty (100 yr). The samples show a distinct layering effect, that is, the copper base material shows separate oxide and basic sulfate layers on all samples, indicating that patina is not a homogeneous mixture of oxides and basic sulfates

  18. Genome Sequences of Two Copper-Resistant Escherichia coli Strains Isolated from Copper-Fed Pigs

    DEFF Research Database (Denmark)

    Lüthje, Freja L.; Hasman, Henrik; Aarestrup, Frank Møller

    2014-01-01

    The draft genome sequences of two copper-resistant Escherichia coli strains were determined. These had been isolated from copper-fed pigs and contained additional putative operons conferring copper and other metal and metalloid resistances.......The draft genome sequences of two copper-resistant Escherichia coli strains were determined. These had been isolated from copper-fed pigs and contained additional putative operons conferring copper and other metal and metalloid resistances....

  19. Copper-Containing Anti-Biofilm Nanofiber Scaffolds as a Wound Dressing Material.

    Directory of Open Access Journals (Sweden)

    Jayesh J Ahire

    Full Text Available Copper particles were incorporated into nanofibers during the electrospinning of poly-D,L-lactide (PDLLA and poly(ethylene oxide (PEO. The ability of the nanofibers to prevent Pseudomonas aeruginosa PA01 and Staphylococcus aureus (strain Xen 30 to form biofilms was tested. Nanofibers containing copper particles (Cu-F were thinner (326 ± 149 nm in diameter, compared to nanofibers without copper (CF; 445 ± 93 nm in diameter. The crystalline structure of the copper particles in Cu-F was confirmed by X-ray diffraction (XRD. Copper crystals were encapsulated, but also attached to the surface of Cu-F, as shown scanning transmission electron microscopy (STEM and transmission electron microscopy (TEM, respectively. The copper particles had no effect on the thermal degradation and thermal behaviour of Cu-F, as shown by thermogravimetric analysis (TGA and differential scanning calorimeter (DSC. After 48 h in the presence of Cu-F, biofilm formation by P. aeruginosa PA01 and S. aureus Xen 30 was reduced by 41% and 50%, respectively. Reduction in biofilm formation was ascribed to copper released from the nanofibers. Copper-containing nanofibers may be incorporated into wound dressings.

  20. The involvement of vimentin in copper-induced regression of cardiomyocyte hypertrophy.

    Science.gov (United States)

    Li, Rui; Bourcy, Katherine; Wang, Tao; Sun, Miao; Kang, Y James

    2015-09-01

    Dietary copper supplementation reverses the pressure overload-induced cardiac hypertrophy. Activation of vascular endothelial growth factor receptor-1 (VEGFR-1) and cyclic guanosine monophosphate (cGMP)-dependent protein kinase-1 (PKG-1) is required for the regression. The present study was undertaken to determine the link between VEGFR-1 and PKG-1 in copper regression of cardiomyocyte hypertrophy. Human cardiac myocytes (HCM) or primary cultures of neonatal rat cardiomyocytes were exposed to phenylephrine (PE) at a final concentration of 100 μM for 48 h to induce cell hypertrophy. Copper sulfite was added to cultures of hypertrophic cardiomyocytes at a final concentration of 5 μM elemental copper and incubated for 24 h to reverse cell hypertrophy. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis identified a 56 kDa copper-binding protein, vimentin, which was co-immunoprecipitated with VEGFR-1 and PKG-1. Copper supplementation increased vimentin levels and enhanced PKG-1 activity. Gene silencing using siRNA targeting vimentin prevented copper-induced elevation of vimentin, depressed the activity of PKG-1, and blocked the copper-induced regression of cardiomyocyte hypertrophy. This study demonstrates that vimentin is critically involved in the VEGFR-1 mediated activation of the PKG-1 signaling pathway, leading to regression of cardiomyocyte hypertrophy.

  1. Copper Contamination Impairs Herbivore Initiation of Seaweed Inducible Defenses and Decreases Their Effectiveness

    Science.gov (United States)

    2015-01-01

    Seaweed-herbivore interactions are often mediated by environmental conditions, yet the roles of emerging anthropogenic stressors on these interactions are poorly understood. For example, chemical contaminants have unknown consequences on seaweed inducible resistance and herbivore response to these defenses despite known deleterious effects of contaminants on animal inducible defenses. Here, we investigated the effect of copper contamination on the interactions between a snail herbivore and a brown seaweed that displays inducible resistance to grazing. We examined seaweed inducible resistance and its effectiveness for organisms exposed to copper at two time points, either during induction or after herbivores had already induced seaweed defenses. Under ambient conditions, non-grazed tissues were more palatable than grazed tissues. However, copper additions negated the preference for non-grazed tissues regardless of the timing of copper exposure, suggesting that copper decreased both how herbivores initiated these inducible defenses and their subsequent effectiveness. Copper decreased stimulation of defenses, at least in part, by suppressing snail grazing pressure—the cue that turns inducible defenses on. Copper decreased effectiveness of defenses by preventing snails from preferentially consuming non-grazed seaweed. Thus, contaminants can potentially stress communities by changing seaweed-herbivore interactions mediated via inducible defenses. Given the ubiquity of seaweed inducible resistance and their potential influence on herbivores, we hypothesize that copper contamination may change the impact of these resistant traits on herbivores. PMID:26274491

  2. Copper Contamination Impairs Herbivore Initiation of Seaweed Inducible Defenses and Decreases Their Effectiveness.

    Directory of Open Access Journals (Sweden)

    Alexandria M Warneke

    Full Text Available Seaweed-herbivore interactions are often mediated by environmental conditions, yet the roles of emerging anthropogenic stressors on these interactions are poorly understood. For example, chemical contaminants have unknown consequences on seaweed inducible resistance and herbivore response to these defenses despite known deleterious effects of contaminants on animal inducible defenses. Here, we investigated the effect of copper contamination on the interactions between a snail herbivore and a brown seaweed that displays inducible resistance to grazing. We examined seaweed inducible resistance and its effectiveness for organisms exposed to copper at two time points, either during induction or after herbivores had already induced seaweed defenses. Under ambient conditions, non-grazed tissues were more palatable than grazed tissues. However, copper additions negated the preference for non-grazed tissues regardless of the timing of copper exposure, suggesting that copper decreased both how herbivores initiated these inducible defenses and their subsequent effectiveness. Copper decreased stimulation of defenses, at least in part, by suppressing snail grazing pressure-the cue that turns inducible defenses on. Copper decreased effectiveness of defenses by preventing snails from preferentially consuming non-grazed seaweed. Thus, contaminants can potentially stress communities by changing seaweed-herbivore interactions mediated via inducible defenses. Given the ubiquity of seaweed inducible resistance and their potential influence on herbivores, we hypothesize that copper contamination may change the impact of these resistant traits on herbivores.

  3. Copper Contamination Impairs Herbivore Initiation of Seaweed Inducible Defenses and Decreases Their Effectiveness.

    Science.gov (United States)

    Warneke, Alexandria M; Long, Jeremy D

    2015-01-01

    Seaweed-herbivore interactions are often mediated by environmental conditions, yet the roles of emerging anthropogenic stressors on these interactions are poorly understood. For example, chemical contaminants have unknown consequences on seaweed inducible resistance and herbivore response to these defenses despite known deleterious effects of contaminants on animal inducible defenses. Here, we investigated the effect of copper contamination on the interactions between a snail herbivore and a brown seaweed that displays inducible resistance to grazing. We examined seaweed inducible resistance and its effectiveness for organisms exposed to copper at two time points, either during induction or after herbivores had already induced seaweed defenses. Under ambient conditions, non-grazed tissues were more palatable than grazed tissues. However, copper additions negated the preference for non-grazed tissues regardless of the timing of copper exposure, suggesting that copper decreased both how herbivores initiated these inducible defenses and their subsequent effectiveness. Copper decreased stimulation of defenses, at least in part, by suppressing snail grazing pressure-the cue that turns inducible defenses on. Copper decreased effectiveness of defenses by preventing snails from preferentially consuming non-grazed seaweed. Thus, contaminants can potentially stress communities by changing seaweed-herbivore interactions mediated via inducible defenses. Given the ubiquity of seaweed inducible resistance and their potential influence on herbivores, we hypothesize that copper contamination may change the impact of these resistant traits on herbivores.

  4. Lung diffusion testing

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003854.htm Lung diffusion testing To use the sharing features on this page, please enable JavaScript. Lung diffusion testing measures how well the lungs exchange gases. This ...

  5. Nonlinear ambipolar diffusion waves

    Energy Technology Data Exchange (ETDEWEB)

    Mendonca, J.T.; Rowlands, G.

    1985-07-01

    The evolution of a plasma perturbation in a neutral gas is considered using the ambipolar diffusion approximation. A nonlinear diffusion equation is derived and, in the one-dimensional case, exact solutions of shock type are obtained.

  6. Use of copper radioisotopes in investigating disorders of copper metabolism

    International Nuclear Information System (INIS)

    Camakaris, J.; Voskoboinik, I.; Brooks, H.; Greenough, M.; Smith, S.; Mercer, J.

    1998-01-01

    Full text: Copper is an essential trace element for life as a number of vital enzymes require it. Copper deficiency can lead to neurological disorders, osteoporosis and weakening of arteries. However Cu is also highly toxic and homeostatic mechanisms have evolved to maintain Cu at levels which satisfy requirements but do not cause toxicity. Toxicity is mediated by the oxidative capacity of Cu and its ability to generate toxic free radicals. There are several acquired and inherited diseases due to either Cu toxicity or Cu deficiency. The study of these diseases facilitates identification of genes and proteins involved in copper homeostasis, and this in turn will provide rational therapeutic approaches. Our studies have focused on Menkes disease in humans which is an inherited and usually lethal copper deficiency. Using copper radioisotopes 64 Cu (t 1/2 = 12.8 hr) and 67 Cu (t 1/2 = 61 hr) we have studied the protein which is mutated in Menkes disease. This is a transmembrane copper pump which is responsible for absorption of copper into the body and also functions to pump out excess Cu from cells when Cu is elevated. It is therefore a vital component of normal Cu homeostasis. We have provided the first biochemical evidence that the Menkes protein functions as a P-type ATPase Cu pump (Voskoboinik et al., FEBS Letters, in press) and these data will be discussed. The assay involved pumping of radiocopper into purified membrane vesicles. Furthermore we have transfected normal and mutant Menkes genes into cells and are carrying out structure-function studies. We are also studying the role of amyloid precursor protein (APP) as a Cu transport protein in order to determine how Cu regulates this protein and its cleavage products. These studies will provide vital information on the relationship between Cu and APP and processes which lead to Alzheimers disease

  7. A Development Methodology for Copper End Termination Paste — Part 1: Origin of Green Defects

    OpenAIRE

    Kumar, Umesh

    2002-01-01

    Copper (Cu) based pastes have emerged as the termination materials of choice for ceramic capacitors with base metal internal electrodes. To prevent oxidation of nickel (Ni) internal electrode and the copper terminations, it is necessary to fire the terminations in a nitrogen atmosphere. This requirement places significant restrictions on raw material selection for the termination pastes. For example, acrylic-based resins are used as organic binder for their clean burning characteristics ov...

  8. Dual Damascene copper interconnects with low-k polymer dielectrics

    Science.gov (United States)

    Price, David Thomas

    To increase the speed of integrated circuits (ICs), copper interconnects combined with low dielectric constant (low-k) insulators are accepted as the near future replacements for traditional aluminum and silicon dioxide based interconnect technology. In this work, multilevel copper interconnects and low-k polymer insulator fabrication strategies are investigated, with emphasis on integration and two-level metal process realization. Copper interconnects were fabricated with dual Damascene patterning of etching vias and interconnect trenches in the insulator followed by metal deposition and chemical mechanical polishing (CMP) to remove the excess material. The copper adhesion layer and diffusion barrier (or liner) material used was sputtered tantalum. The low-k dielectrics used were vapor deposited parylene-n (PA-n) and spin-on CycloteneTM 5021 divinylsiloxane bisbenzocyclobutene (BCB). PECVD silicon nitride was used as a hard etch mask for dielectric etching, as well as a CMP polish stop, a plasma etch stop and copper diffusion barrier. The dual Damascene processing strategies used to create the via and interconnect pattern were investigated at length. Full integration was performed with four traditional dual Damascene strategies, followed by the development of two unique "clustered hard mask" strategies with full integration of one of them. The fabrication and characterization of dual Damascene copper interconnects led to the defining of eight dual Damascene optimization criteria, specifically addressing polymer dielectrics. Based on polymer dielectric processing considerations and electrical measurements, the clustered hard mask strategies were determined to be superior in comparison to the dual Damascene strategies previously developed for oxide-based dielectrics. The two-level interconnects were characterized by focused ion beam (FIB) cross sectioning and imaging to validate the success of the dual Damascene integration. The average metal-to-metal specific

  9. NID Copper Sample Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kouzes, Richard T.; Zhu, Zihua

    2011-02-01

    The current focal point of the nuclear physics program at PNNL is the MAJORANA DEMONSTRATOR, and the follow-on Tonne-Scale experiment, a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay (0νββ). This experiment requires the use of germanium isotopically enriched in 76Ge. The DEMONSTRATOR will utilize 76Ge from Russia, but for the Tonne-Scale experiment it is hoped that an alternate technology under development at Nonlinear Ion Dynamics (NID) will be a viable, US-based, lower-cost source of separated material. Samples of separated material from NID require analysis to determine the isotopic distribution and impurities. The MAJORANA DEMONSTRATOR is a DOE and NSF funded project with a major science impact. DOE is funding NID through an SBIR grant for development of their separation technology for application to the Tonne-Scale experiment. The Environmental Molecular Sciences facility (EMSL), a DOE user facility at PNNL, has the required mass spectroscopy instruments for making these isotopic measurements that are essential to the quality assurance for the MAJORANA DEMONSTRATOR and for the development of the future separation technology required for the Tonne-Scale experiment. A sample of isotopically separated copper was provided by NID to PNNL for isotopic analysis as a test of the NID technology. The results of that analysis are reported here.

  10. Diffusion during growth and annealing of Co/Cu (111) films

    CERN Document Server

    Su Run; Qian Hai Jie; Kurash

    2002-01-01

    Electronic structure of MBE-grown Co/Cu (111) films was studied by synchrotron radiation angular-resolved photoemission spectra and auger electron spectra during the process of growth and annealing. The experiment reveals that: the energy shift of s-d sub z sup 2 -hybridized band of copper increases with thickening of the coverage of cobalt, which proves that atomic intermixing occurs at the interface, and there is mainly surface diffusion, not bulk interdiffusion during annealing. The authors attribute the diffusion in the two different processes to one driving force, i.e. the surface free energy of cobalt is remarkably larger than that of copper

  11. Research surface resistance of copper normal and abnormal skin-effects depending on the frequency of electromagnetic field

    International Nuclear Information System (INIS)

    Kutovyi, V.A.; Komir, A.I.

    2013-01-01

    The results of the frequency dependence of surface resistance of copper in diffuse and specular reflection of electrons from the conductive surface of the high-frequency resonance of the system depending on the frequency of the electromagnetic field in the normal and anomalous skin effect. Found, the surface resistance of copper is reduced by more than 10 times at the temperature of liquid helium, as compared with a surface resistivity at room temperature, at frequencies f ≤ 173 MHz, for diffuse reflection of conduction electrons from the surface of the conductive layer, and the specular reflection - at frequencies f ≤ 346 MHz

  12. Fabrication of a first wall panel by diffusion bonding

    International Nuclear Information System (INIS)

    Moreschi, L.F.; Pizzuto, A.; Alessandrini, I.

    2002-01-01

    Separated First Wall Panels mechanically attached to a shield block is now the reference concept for the Primary Wall Modules of RTO/RC ITER. The objective of the present work is to demonstrate the practical feasibility of a First Wall Panel utilizing a duplex round (steel) in square (copper) heat sink wound around a steel core and covered by Beryllium armour tiles. These three different materials (Be, Cu, steel) are joined together by diffusion bonding. The Copper alloy/stainless steel and Copper alloy/Beryllium joints were studied and developed selecting the optimal parameters for the related diffusion process. Several specimens were manufactured to be mechanically and thermally tested. The joints were mechanically tested using dedicated press equipment and investigated by micro-structural analysis with optical and SEM microscopy. Some thermal tests were finally carried out using an Electron Beam Facility. A dedicated R and D programme has led to the development of a co-drawing process, suitable for manufacturing the duplex Copper alloy-stainless steel heat sink. Two mock-ups were manufactured, the first in reduced-scale to test the thermal performance of the system, the second of larger scale and geometry better to represent the First Wall Panel

  13. Renal cortex copper concentration in acute copper poisoning in calves

    Directory of Open Access Journals (Sweden)

    Luis E. Fazzio

    2012-01-01

    Full Text Available The aim of this study was to estimate the diagnostic value of renal cortex copper (Cu concentration in clinical cases of acute copper poisoning (ACP. A total of 97 calves that died due to subcutaneous copper administration were compiled in eleven farms. At least, one necropsy was conducted on each farm and samples for complementary analysis were taken. The degree of autolysis in each necropsy was evaluated. The cases appeared on extensive grazing calf breeding and intensive feedlot farms, in calves of 60 to 200 kg body weight. Mortality varied from 0.86 to 6.96 %, on the farms studied. The first succumbed calf was found on the farms between 6 and 72 hours after the susbcutaneous Cu administration. As discrepancies regarding the reference value arose, the local value (19.9 parts per million was used, confirming the diagnosis of acute copper poisoning in 93% of the analyzed kidney samples. These results confirm the value of analysis of the cortical kidney Cu concentration for the diagnosis of acute copper poisoning.

  14. Copper metallurgy at the crossroads

    Directory of Open Access Journals (Sweden)

    Habashi F.

    2007-01-01

    Full Text Available Copper technology changed from the vertical to the horizontal furnace and from the roast reaction to converting towards the end of the last century. However, the horizontal furnace proved to be an inefficient and polluting reactor. As a result many attempts were made to replace it. In the past 50 years new successful melting processes were introduced on an industrial scale that were more energy efficient and less polluting. In addition, smelting and converting were conducted in a single reactor in which the concentrate was fed and the raw copper was produced. The standing problem in many countries, however, is marketing 3 tonnes of sulfuric acid per tonne of copper produced as well as emitting large amounts of excess SO2 in the atmosphere. Pressure hydrometallurgy offers the possibility of liberating the copper industry from SO2 problem. Heap leaching technology has become a gigantic operation. Combined with solvent extraction and electrowinning it contributes today to about 20% of copper production and is expected to grow. Pressure leaching offers the possibility of liberating the copper industry from SO2 problem. The technology is over hundred years old. It is applied for leaching a variety of ores and concentrates. Hydrothermal oxidation of sulfide concentrates has the enormous advantage of producing elemental sulfur, hence solving the SO2 and sulfuric acid problems found in smelters. Precipitation of metals such as nickel and cobalt under hydrothermal conditions has been used for over 50 years. It has the advantage of a compact plant but the disadvantage of producing ammonium sulfate as a co-product. In case of copper, however, precipitation takes place without the need of neutralizing the acid, which is a great advantage and could be an excellent substitute for electrowinning which is energy intensive and occupies extensive space. Recent advances in the engineering aspects of pressure equipment design open the door widely for increased

  15. Deep level centers in electron-irradiated silicon crystals doped with copper at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Yarykin, Nikolai [Institute of Microelectronics Technology, RAS, Chernogolovka (Russian Federation); Weber, Joerg [Technische Universitaet Dresden (Germany)

    2017-07-15

    The effect of bombardment with energetic particles on the deep-level spectrum of copper-contaminated silicon wafers is studied by space charge spectroscopy methods. The p-type FZ-Si wafers were doped with copper in the temperature range of 645-750 C and then irradiated with the 10{sup 15} cm{sup -2} fluence of 5 MeV electrons at room temperature. Only the mobile Cu{sub i} species and the Cu{sub PL} centers are detected in significant concentrations in the non-irradiated Cu-doped wafers. The properties of the irradiated samples are found to qualitatively depend on the copper in-diffusion temperature T{sub diff}. For T{sub diff} > 700 C, the irradiation partially reduces the Cu{sub i} concentration and introduces additional Cu{sub PL} centers while no standard radiation defects are detected. If T{sub diff} was below ∝700 C, the irradiation totally removes the mobile Cu{sub i} species. Instead, the standard radiation defects and their complexes with copper appear in the deep-level spectrum. A model for the defects reaction scheme during the irradiation is derived and discussed. DLTS spectrum of the Cu-contaminated and then irradiated silicon qualitatively depends on the copper in-diffusion temperature. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Fractional diffusion equations and anomalous diffusion

    CERN Document Server

    Evangelista, Luiz Roberto

    2018-01-01

    Anomalous diffusion has been detected in a wide variety of scenarios, from fractal media, systems with memory, transport processes in porous media, to fluctuations of financial markets, tumour growth, and complex fluids. Providing a contemporary treatment of this process, this book examines the recent literature on anomalous diffusion and covers a rich class of problems in which surface effects are important, offering detailed mathematical tools of usual and fractional calculus for a wide audience of scientists and graduate students in physics, mathematics, chemistry and engineering. Including the basic mathematical tools needed to understand the rules for operating with the fractional derivatives and fractional differential equations, this self-contained text presents the possibility of using fractional diffusion equations with anomalous diffusion phenomena to propose powerful mathematical models for a large variety of fundamental and practical problems in a fast-growing field of research.

  17. Electrochemical characterization of anode passivation mechanisms in copper electrorefining

    Science.gov (United States)

    Moats, Michael Scott

    Anode passivation can decrease productivity and quality while increasing costs in modern copper electrorefineries. This investigation utilized electrochemical techniques to characterize the passivation behavior of anode samples from ten different operating companies. It is believed that this collection of anodes is the most diverse set ever to be assembled to study the effect of anode composition on passivation. Chronopotentiometry was the main electrochemical technique, employing a current density of 3820 A m-2. From statistical analysis of the passivation characteristics, increasing selenium, tellurium, silver, lead and nickel were shown to accelerate passivation. Arsenic was the only anode impurity that inhibited passivation. Oxygen was shown to accelerate passivation when increased from 500 to 1500 ppm, but further increases did not adversely affect passivation. Nine electrolyte variables were also examined. Increasing the copper, sulfuric acid or sulfate concentration of the electrolyte accelerated passivation. Arsenic in the electrolyte had no effect on passivation. Chloride and optimal concentrations of thiourea and glue delayed passivation. Linear sweep voltammetry, cyclic voltammetry, and impedance spectroscopy provided complementary information. Analysis of the electrochemical results led to the development of a unified passivation mechanism. Anode passivation results from the formation of inhibiting films. Careful examination of the potential details, especially those found in the oscillations just prior to passivation, demonstrated the importance of slimes, copper sulfate and copper oxide. Slimes confine dissolution to their pores and inhibit diffusion. This can lead to copper sulfate precipitation, which blocks more of the surface area. Copper oxide forms because of the resulting increase in potential at the interface between the copper sulfate and anode. Ultimate passivation occurs when the anode potential is high enough to stabilize the oxide film in

  18. In situ antimicrobial behavior of materials having copper-based additives in a hospital environment.

    Science.gov (United States)

    Palza, Humberto; Nuñez, Mauricio; Bastías, Roberto; Delgado, Katherine

    2018-02-19

    Copper and its alloys are recognized as effective antimicrobial surface materials at the laboratory scale as well as in clinical trials. Copper has been used in the healthcare setting to reduce environmental contamination and thus prevent healthcare-associated infections, complementing traditional protocols. The addition of copper nanoparticles to polymer/plastic matrices can also produce antimicrobial materials as confirmed under laboratory conditions. However, there is a lack of studies validating the antimicrobial behavior of these nanocomposite materials in clinical trials. To satisfy this issue, plastic waiting room chairs having embedded metal copper nanoparticles, as well as metal hospital IV pools coated with an organic paint having nanostructured zeolite/copper particles, were produced and tested in a hospital environment. These prototypes were sampled once weekly for 10 weeks and the viable microorganisms were analyzed and compared to the materials not containing copper. In the waiting rooms, chairs with copper reduced around 73% the total viable micro-organisms present, showing activity regardless of the microorganism tested. Regarding the IV pools installed in operating rooms, despite the low amount of microorganisms present due to the rigorous hygiene protocols, samples with copper presented lower total viable microorganisms than unfilled materials. Although some results did not have statistical significance because of the low load of microorganisms, during at least three weeks the IV pools with copper were able to reduce with statistical significance by 50% the amount of micro-organisms. These findings show for the first time the feasibility of applying the antimicrobial property of copper t by adding nanosized fillers to other materials in a hospital environment. Copyright © 2018 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  19. ANTIVIRAL ACTIVITY OF COPPER(IICHLORIDE DIHYDRATE AGAINST DENGUE VIRUS TYPE-2 IN VERO CELL

    Directory of Open Access Journals (Sweden)

    Teguh Hari Sucipto

    2017-04-01

    Full Text Available Infection of dengue virus (DENV was number of globally significant emerging pathogen. Antiviral dengue therapies ar importantly needed to control emerging dengue. Dengue virus (DENV is mosquito-borne arboviruses responsible for causing acute systemic diseases and grievous health conditions in humans. To date, there is no clinically approved dengue vaccine or antiviral for humans, even though there have been great efforts towards this end. Copper and copper compounds have more effective in inactivation viruses, likes an influenza virus and human immunodeficiency virus (HIV. Purpose in this project was investigated of Copper(IIchloride Dihydrate antiviral compound were further tested for inhibitory effect on the replication of DENV-2 in cell culture. DENV replication was measures by Enzyme linked Immunosorbent Assay (ELISA with selectivity index value (SI was determined as the ratio of cytotoxic concentration 50 (CC50 to inhibitory concentration 50 (IC50 for compound. The maximal inhibitory concentration (IC50 of Copper(IIchloride Dihydrate against dengue virus type-2 was 0.13 μg/ml. The cytotoxic concentration (CC50 of compound against Vero cell was 5.03 μg/ml. The SI values for Copper(IIchloride Dihydrate 38.69. Result of this study suggest that Copper(IIchloride Dihydrate demonstated significant anti-DENV-2 inhibitory activities and not toxic in the Vero cells. Copper mechanisms play an important role in the prevention of copper toxicity, exposure to excessive levels of copper can result in a number of adverse health effects, as a result increased reactive oxygen species and oxidative damage to lipid, DNA, and proteins have been observed in human cell culture models or clinical syndromes of severe copper deficiency and inhibition was attributed to released cupric ions which react with cysteine residues on the surface of the protease.

  20. Anisotropy of low dielectric constant materials and reliability of copper/low-k interconnects

    Science.gov (United States)

    Cho, Taiheui

    2000-10-01

    Cu/low-k material interconnects are a solution to overcome problems that occur in deep submicron Al/SiO2 based interconnects. Several challenges have to be resolved before successfully integrating copper and low-k dielectric materials into interconnects. In this work, Cu and several low-k polymers were used for interconnect applications and their effects on interconnect performance were investigated. Dielectric anisotropy is one of the factors that affect interconnect performance. Two fluorinated polymers, a rigid rod-like polyimide (Dupont FPI-136M) and a flexible poly(aryl ether) (Allied Signal FLARE 1.51) were used to investigate the relationship between dielectric anisotropy and molecular orientation. The dielectric anisotropy of the rigid rod-like polyimide was reduced relative to that in blanket films when it was confined in submicron trenches. Such a reduction was not observed in the flexible polymer. Polarized FTIR experiments showed that when rigid rod-like polymer was confined in submicron trenches polymer chains preferentially oriented parallel to metal lines. The preferential orientation reduced the in-plane dielectric constant of the polymer. A barrier layer has to be used to prevent Cu diffusion into an interlayer dielectric material. Ta, TaN, and TaSiN were used to investigate the relationship between barrier capability and microstructures using a bias temperature stress. TaSiN performed best because TaSiN was amorphous, followed by TaN then Ta because TaN had impurities segregated in grain boundaries. When Cu/BCB interconnects were fabricated and their reliability was investigated with the bias temperature stress, some of the interconnect structures performed properly and their life times were comparable to those of Cu/SiO2 interconnects, while other interconnect structures rapidly failed because the Cu readily diffused through defects in the barrier. The defects were introduced during chemical-mechanical polishing and plasma etching processes.

  1. Neutron-activation analysis of copper in food-stuffs and biomedium of organism

    International Nuclear Information System (INIS)

    Rasulov, S.K.

    2004-01-01

    microelements in hairs of school age children it is important to take into consideration the possible changes related with sex and biogeochemical area of living place of subjects to be investigated. Girls of puberty age require more copper than boys and this should be taken into account during taking preventive measures regarding this micro element among them. According to our revealed limits of normal copper content data in children of school age we recommend the possibility of implementation into practice the limits of normal copper content data in diagnosis of copper deficiency in condition of Zarafshon valley. To study copper deficiency rate among children of school age we have used working values-conditionally-possible level and critical level based on the data referring to lower limits of physiologic content of elements in hairs, as per A.V. Skalny (1999). All children with deficiency of possible level of copper in hairs were referred to the risk group and fundamental study of the latter was done later on. Investigation revealed that deviation in structure of element in hair too high: copper deficiency in children studied made up more than 51%, and in rural area -70%. In contradistinction to Moscow children, the dis balance of copper in our children investigated occurs more often (as per A.V. Skalny copper dis balance rate among children in Moscow equaled to 45%). Main after effects of Such copper deficiency as follows: impairment of growth and development data, increase of iron and copper deficiency status rate and some other combined microelementosis in children

  2. Oxidation of aromatic alcohols on zeolite-encapsulated copper amino acid complexes

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, S.; Teixeira Florencio, J.M. [Kaiserslautern Univ. (Germany). Dept. of Chemistry, Chemical Technology

    1998-12-31

    Copper complexes of the amino acids histidine, arginine and lysine have been introduced into the supercages of zeolite Y and, for the first time, into the large intracrystalline cavities of zeolites EMT and MCM-22. The resulting host/guest compounds are characterized by X-ray powder diffraction, UV/VIS-spectroscopy in the diffuse reflectance mode and by catalytic tests in the liquid-phase oxidation of aromatic alcohols (viz. benzyl alcohol, 2- and 3-methylbenzyl alcohol and 2,5-dimethylbenzyl alcohol) with tertiary-butylhydroperoxide as oxidant. It was observed that intracrystalline copper-amino acid complexes possess remarkable catalytic activity, yielding the corresponding aromatic aldehydes and acids. (orig.)

  3. Growth Mechanism for Low Temperature PVD Graphene Synthesis on Copper Using Amorphous Carbon

    Science.gov (United States)

    Narula, Udit; Tan, Cher Ming; Lai, Chao Sung

    2017-03-01

    Growth mechanism for synthesizing PVD based Graphene using Amorphous Carbon, catalyzed by Copper is investigated in this work. Different experiments with respect to Amorphous Carbon film thickness, annealing time and temperature are performed for the investigation. Copper film stress and its effect on hydrogen diffusion through the film grain boundaries are found to be the key factors for the growth mechanism, and supported by our Finite Element Modeling. Low temperature growth of Graphene is achieved and the proposed growth mechanism is found to remain valid at low temperatures.

  4. Biliary copper excretion by hepatocyte lysosomes in the rat. Major excretory pathway in experimental copper overload

    International Nuclear Information System (INIS)

    Gross, J.B. Jr.; Myers, B.M.; Kost, L.J.; Kuntz, S.M.; LaRusso, N.F.

    1989-01-01

    We investigated the hypothesis that lysosomes are the main source of biliary copper in conditions of hepatic copper overload. We used a rat model of oral copper loading and studied the relationship between the biliary output of copper and lysosomal hydrolases. Male Sprague-Dawley rats were given tap water with or without 0.125% copper acetate for up to 36 wk. Copper loading produced a 23-fold increase in the hepatic copper concentration and a 30-65% increase in hepatic lysosomal enzyme activity. Acid phosphatase histochemistry showed that copper-loaded livers contained an increased number of hepatocyte lysosomes; increased copper concentration of these organelles was confirmed directly by both x ray microanalysis and tissue fractionation. The copper-loaded rats showed a 16-fold increase in biliary copper output and a 50-300% increase in biliary lysosomal enzyme output. In the basal state, excretory profiles over time were similar for biliary outputs of lysosomal enzymes and copper in the copper-loaded animals but not in controls. After pharmacologic stimulation of lysosomal exocytosis, biliary outputs of copper and lysosomal hydrolases in the copper-loaded animals remained coupled: injection of colchicine or vinblastine produced an acute rise in the biliary output of both lysosomal enzymes and copper to 150-250% of baseline rates. After these same drugs, control animals showed only the expected increase in lysosomal enzyme output without a corresponding increase in copper output. We conclude that the hepatocyte responds to an increased copper load by sequestering excess copper in an increased number of lysosomes that then empty their contents directly into bile. The results provide direct evidence that exocytosis of lysosomal contents into biliary canaliculi is the major mechanism for biliary copper excretion in hepatic copper overload

  5. Leaching of Copper Ore by Thiobacillus Ferrooxidans.

    Science.gov (United States)

    Lennox, John; Biaha, Thomas

    1991-01-01

    A quantitative laboratory exercise based upon the procedures copper manufacturers employ to increase copper production is described. The role of chemoautotrophic microorganisms in biogeologic process is emphasized. Safety considerations when working with bacteria are included. (KR)

  6. Electrochemical behaviour of alkaline copper complexes

    Indian Academy of Sciences (India)

    cyanide- plating bath for copper has been developed using alkaline trisodium citrate and triethanolamine solutions5. The present investigation presents cyclic voltammetric studies on the electrochemical behaviour of alkaline copper complexes, ...

  7. Testing Corrosion Inhibitors for the Conservation of Archaeological Copper and Copper Alloys

    Directory of Open Access Journals (Sweden)

    Robert B. Faltermeier

    1997-11-01

    Full Text Available This is a synopsis of the Ph.D. research undertaken at the Institute of Archaeology, University College London. The aim was to evaluate corrosion inhibitors for use in the conservation of copper and copper alloy archaeological artefacts. The objective of this work was to acquire an insight into the performance of copper corrosion inhibitors, when applied to archaeological copper.

  8. Copper tolerance of Trichoderma species

    Directory of Open Access Journals (Sweden)

    Jovičić-Petrović Jelena

    2014-01-01

    Full Text Available Some Trichoderma strains can persist in ecosystems with high concentrations of heavy metals. The aim of this research was to examine the variability of Trichoderma strains isolated from different ecosystems, based on their morphological properties and restriction analysis of ITS fragments. The fungal growth was tested on potato dextrose agar, amended with Cu(II concentrations ranging from 0.25 to 10 mmol/l, in order to identify copper-resistant strains. The results indicate that some isolated strains of Trichoderma sp. show tolerance to higher copper concentrations. Further research to examine the ability of copper bioaccumulation by tolerant Trichoderma strains is needed. [Projekat Ministarstva nauke Republike Srbije, br. TR 31080 i br. III 43010

  9. Mechanochemical reduction of copper sulfide

    DEFF Research Database (Denmark)

    Balaz, P.; Takacs, L.; Jiang, Jianzhong

    2002-01-01

    The mechanochemical reduction of copper sulfide with iron was induced in a Fritsch P-6 planetary mill, using WC vial filled with argon and WC balls. Samples milled for specific intervals were analyzed by XRD and Mossbauer spectroscopy. Most of the reaction takes place during the first 10 min...... of milling and only FeS and Cu are found after 60 min. The main chemical process is accompanied by phase transformations of the sulfide phases as a result of milling. Djurleite partially transformed to chalcocite and a tetragonal copper sulfide phase before reduction. The cubic modification of FeS was formed...... first, transforming to hexagonal during the later stages of the process. The formation of off-stoichiometric phases and the release of some elemental sulfur by copper sulfide are also probable....

  10. Laser sintering of copper nanoparticles

    International Nuclear Information System (INIS)

    Zenou, Michael; Saar, Amir; Ermak, Oleg; Kotler, Zvi

    2014-01-01

    Copper nanoparticle (NP) inks serve as an attractive potential replacement to silver NP inks in functional printing applications. However their tendency to rapidly oxidize has so far limited their wider use. In this work we have studied the conditions for laser sintering of Cu-NP inks in ambient conditions while avoiding oxidation. We have determined the regime for stable, low-resistivity copper (< ×3 bulk resistivity value) generation in terms of laser irradiance and exposure duration and have indicated the limits on fast processing. The role of pre-drying conditions on sintering outcome has also been studied. A method, based on spectral reflectivity measurements, was used for non-contact monitoring of the sintering process evolution. It also indicates preferred spectral regions for sintering. Finally, we illustrated how selective laser sintering can generate high-quality, fine line (<5 µm wide) and dense copper circuits. (paper)

  11. Formation of complexes between functionalized chitosan membranes and copper: A study by angle resolved XPS

    Energy Technology Data Exchange (ETDEWEB)

    Jurado-López, Belén [Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga (Spain); Vieira, Rodrigo Silveira [Chemical Engineering Department, Universidade Federal do Ceará, UFC, 60455-760 Fortaleza, CE (Brazil); Rabelo, Rodrigo Balloni; Beppu, Marisa Masumi [School of Chemical Engineering, University of Campinas, UNICAMP, P.O. Box 6066, 13081-970 Campinas, SP (Brazil); Casado, Juan [Departamento de Química-Física, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga (Spain); Rodríguez-Castellón, Enrique, E-mail: castellon@uma.es [Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga (Spain)

    2017-01-01

    Chitosan is a biopolymer with potential applications in various fields. Recently, it has been used for heavy metals removal like copper, due to the presence of amino and hydroxyl groups in its structure. Chitosan membranes were crosslinked with epichlorohydrin and bisoxirano and functionalized with chelating agents, such as iminodiacetic acid, aspartic acid and tris-(2-amino-ethyl) polyamine. These membranes were used for copper adsorption and the formed complexes were characterized. Thermal and crystalline properties of chitosan membranes were studied by TG-DCS and X-ray diffraction. Raman, XPS and FT-IR data confirmed that copper is linked to the modified chitosan membranes by the amino groups. The oxidation state of copper-chitosan membranes were also studied by angle resolved XPS, and by UV–Vis diffuse reflectance spectroscopy. - Highlights: • Chitosan membranes were crosslinked with epichlorohydrin and bisoxirano and functionalized with chelating agents. • The chelating agent were iminodiacetic acid, aspartic acid and tris-(2-amino-ethyl) polyamine. • The functionalized membranes were used for copper adsorption and studied by ARXPS, Raman, TG-DCS, FT-IR and XRD. • Spectroscopic data confirmed that copper is linked to the modified chitosan membranes by the amino groups.

  12. High temperature investigations on optimising the recovery of copper from waste printed circuit boards.

    Science.gov (United States)

    Cayumil, R; Ikram-Ul-Haq, M; Khanna, R; Saini, R; Mukherjee, P S; Mishra, B K; Sahajwalla, V

    2018-03-01

    High temperature pyrolysis investigations were carried out on waste printed circuit boards (PCBs) in the temperature range 800-1000°C under inert conditions, with an aim to determine optimal operating conditions for the recovery of copper. Pyrolysis residues were characterized using ICP-OES analysis, SEM/EDS and XRD investigations. Copper foils were successfully recovered after pyrolysis at 800°C for 10-20 min; the levels of Pb and Sn present were found to be quite low and these were generally present near the foil edges. The relative proportions of Pb and Sn became progressively higher at longer heating times due to enhanced diffusion of these molten metals in solid copper. While a similar behaviour was observed at 900°C, the pyrolysis at 1000°C resulted in copper forming Cu-Sn-Pb alloys; copper foils could no longer be recovered. Optimal conditions were identified for the direct recovery of copper from waste PCBs with minimal processing. This approach is expected to make significant contributions towards enhancing material recovery, process efficiency and the environmental sustainability of recycling e-waste. Pyrolysis at lower temperatures, short heating times, coupled with reductions in process steps are expected to significantly reduce energy consumption and pollution associated with the handling and processing of waste PCBs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Refining processes in the copper casting technology

    OpenAIRE

    Rzadkosz, S.; Kranc, M.; Garbacz-Klempka, A.; Kozana, J.; Piękoś, M.

    2015-01-01

    The paper presents the analysis of technology of copper and alloyed copper destined for power engineering casts. The casts quality was assessed based on microstructure, chemical content analysis and strength properties tests. Characteristic deoxidising (Logas, Cup) and modifying (ODM2, Kupmod2) formulas were used for the copper where high electrical conductivity was required. Chosen examples of alloyed copper with varied Cr and Zr content were studied, and the optimal heat treatment parameter...

  14. Tunable synthesis of copper nanotubes

    International Nuclear Information System (INIS)

    Kaniukov, E; Yakimchuk, D; Kozlovsky, A; Shlimas, D; Zdorovets, M; Kadyrzhanov, K

    2016-01-01

    Simple method of tunable synthesis of copper nanotubes based on template synthesis was developed. A comprehensive study of the structural, morphological and electrical characteristics of the obtained nanostructures was carried out. Characterization of structural features was made by methods of scanning electron microscopy, energy dispersive spectroscopy and X-ray diffractometry analysis. Evaluation of wall thickness is made by methods of gas permeability. Electrical conductivity of nanotubes was define in the study of their current-voltage characteristics. The possibility to control of copper nanotubes physical properties by variation of the deposition parameters was shown. (paper)

  15. A statistical approach to the experimental design of the sulfuric acid leaching of gold-copper ore

    Directory of Open Access Journals (Sweden)

    Mendes F.D.

    2003-01-01

    Full Text Available The high grade of copper in the Igarapé Bahia (Brazil gold-copper ore prevents the direct application of the classic cyanidation process. Copper oxides and sulfides react with cyanides in solution, causing a high consumption of leach reagent and thereby raising processing costs and decreasing recovery of gold. Studies have showm that a feasible route for this ore would be a pretreatment for copper minerals removal prior to the cyanidation stage. The goal of this experimental work was to study the experimental conditions required for copper removal from Igarapé Bahia gold-copper ore by sulfuric acid leaching by applying a statistical approach to the experimental design. By using the Plackett Burman method, it was possible to select the variables that had the largest influence on the percentage of copper extracted at the sulfuric acid leaching stage. These were temperature of leach solution, stirring speed, concentration of sulfuric acid in the leach solution and particle size of the ore. The influence of the individual effects of these variables and their interactions on the experimental response were analyzed by applying the replicated full factorial design method. Finally, the selected variables were optimized by the ascending path statistical method, which determined the best experimental conditions for leaching to achieve the highest percentage of copper extracted. Using the optimized conditions, the best leaching results showed a copper extraction of 75.5%.

  16. Evaluation of copper ion of antibacterial effect on Pseudomonas aeruginosa, Salmonella typhimurium and Helicobacter pylori and optical, mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young-Hwan [School of Materials Science and Engineering, University of Yonsei, Seoul (Korea, Republic of); Choi, Yu-ri; Kim, Kwang-Mahn [Department and Research Institute of Dental Biomaterials and Bioengineering, College of Dentistry, University of Yonsei, Seoul (Korea, Republic of); Choi, Se-Young, E-mail: sychoi@yonsei.ac.kr [School of Materials Science and Engineering, University of Yonsei, Seoul (Korea, Republic of)

    2012-02-01

    Antibacterial effect on Pseudomonas aeruginosa, Salmonella typhimurium and Helicobacter pylori of copper ion was researched. Also, additional effects of copper ion coating on optical and mechanical properties were researched as well. Copper ion was coated on glass substrate as a thin film to prevent bacteria from growing. Cupric nitrate was used as precursors for copper ion. The copper ion contained sol was deposited by spin coating process on glass substrate. Then, the deposited substrates were heat treated at the temperature range between 200 Degree-Sign C and 250 Degree-Sign C. The thickness of deposited copper layer on the surface was 63 nm. The antibacterial effect of copper ion coated glass on P. aeruginosa, S. typhimurium and H. pylori demonstrated excellent effect compared with parent glass. Copper ion contained layer on glass showed a similar value of transmittance compared with value of parent glass. The 3-point bending strength and Vickers hardness were 209.2 MPa, 540.9 kg/mm{sup 2} which were about 1.5% and 1.3% higher than the value of parent glass. From these findings, it is clear that copper ion coating on glass substrate showed outstanding effect not only in antibacterial activity but also in optical and mechanical properties as well.

  17. Electrical conduction in composites containing copper core–copper ...

    Indian Academy of Sciences (India)

    Unknown

    of Mott's small polaron hopping conduction model. ... sample exhibited a metallic conduction confirming the formation of a percolative chain of ..... value of εp. Also the oxide layer formation on the initially unoxidized copper particles will increase the resistivity level of the nanocomposite. This is borne out by results shown in ...

  18. Joining of alumina via copper/niobium/copper interlayers

    Energy Technology Data Exchange (ETDEWEB)

    Marks, Robert A.; Chapman, Daniel R.; Danielson, David T.; Glaeser, Andreas M.

    2000-03-15

    Alumina has been joined at 1150 degrees C and 1400 degrees C using multilayer copper/niobium/copper interlayers. Four-point bend strengths are sensitive to processing temperature, bonding pressure, and furnace environment (ambient oxygen partial pressure). Under optimum conditions, joints with reproducibly high room temperature strengths (approximately equal 240 plus/minus 20 MPa) can be produced; most failures occur within the ceramic. Joints made with sapphire show that during bonding an initially continuous copper film undergoes a morphological instability, resulting in the formation of isolated copper-rich droplets/particles at the sapphire/interlayer interface, and extensive regions of direct bonding between sapphire and niobium. For optimized alumina bonds, bend tests at 800 degrees C-1100 degrees C indicate significant strength is retained; even at the highest test temperature, ceramic failure is observed. Post-bonding anneals at 1000 degrees C in vacuum or in gettered argon were used to assess joint stability and to probe the effect of ambient oxygen partial pressure on joint characteristics. Annealing in vacuum for up to 200 h causes no significant decrease in room temperature bend strength or change in fracture path. With increasing anneal time in a lower oxygen partial pressure environment, the fracture strength decreases only slightly, but the fracture path shifts from the ceramic to the interface.

  19. Structure transitions between copper-sulphate and copper-chloride ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Structure transitions between copper UPD adlayers on Au(111)–(1 × 1) in sulfuric acid and chloride containing electrolyte were investigated by in situ scanning tunnelling microscopy. We demon- strate that co-adsorbed sulphate ions in the (√3 × √3)R30° UPD adlayer are replaced by chloride ions and,.

  20. Hereditary Diffuse Infiltrating Retinoblastoma.

    Science.gov (United States)

    Schedler, Katharina J E; Traine, Peter G; Lohmann, Dietmar R; Haritoglou, Christos; Metz, Klaus A; Rodrigues, Eduardo B

    2016-01-01

    Retinoblastoma is one of the most common childhood cancers. The diffuse infiltrating retinoblastoma is a rare subtype of this neoplasm. The majority of cases of diffuse infiltrating retinoblastoma are unilateral and occur sporadically. Herein we report on a family with three children affected by retinoblastoma, among them one girl with diffuse infiltrating retinoblastoma. This girl was diagnosed at the age of 8 years with a unilateral diffuse infiltrating retinoblastoma. By contrast, the two brothers became clinically apparent in the first 2 years of life with bilateral retinoblastoma. The parents were clinically unremarkable. Genetic analysis of RB1 gene was performed. The girl with diffuse infiltrating RB was found to be heterozygous for an oncogenic mutation in the RB1 gene that was also carried by both brothers and the father of the family. These results show that diffuse infiltrating retinoblastoma can develop on the background of a hereditary predisposition to retinoblastoma.

  1. Metric diffusion along foliations

    CERN Document Server

    Walczak, Szymon M

    2017-01-01

    Up-to-date research in metric diffusion along compact foliations is presented in this book. Beginning with fundamentals from the optimal transportation theory and the theory of foliations; this book moves on to cover Wasserstein distance, Kantorovich Duality Theorem, and the metrization of the weak topology by the Wasserstein distance. Metric diffusion is defined, the topology of the metric space is studied and the limits of diffused metrics along compact foliations are discussed. Essentials on foliations, holonomy, heat diffusion, and compact foliations are detailed and vital technical lemmas are proved to aide understanding. Graduate students and researchers in geometry, topology and dynamics of foliations and laminations will find this supplement useful as it presents facts about the metric diffusion along non-compact foliation and provides a full description of the limit for metrics diffused along foliation with at least one compact leaf on the two dimensions.

  2. Copper-polymer nanocomposites: An excellent and cost-effective biocide for use on antibacterial surfaces.

    Science.gov (United States)

    Tamayo, Laura; Azócar, Manuel; Kogan, Marcelo; Riveros, Ana; Páez, Maritza

    2016-12-01

    The development of polymer nanocomposites with antimicrobial properties has been a key factor for controlling or inhibiting the growth of microorganisms and preventing foodborne diseases and nosocomial infections. Commercially available antibacterial products based on silver-polymer are the most widely used despite the fact that copper is considerably less expensive. The incorporation of copper nanoparticles as antibacterial agents in polymeric matrices to generate copper-polymer nanocomposites have presented excellent results in inhibiting the growth of a broad spectrum of microorganisms. The potential applications in food packaging, medical devices, textiles and pharmaceuticals and water treatment have generated an increasing number of investigations on preparing copper based nanocomposites and alternative polymeric matrices, as potential hosts of nano-modifiers. This review presents a comprehensive compilation of previous published work on the subject, mainly related to the antimicrobial activity of copper polymer nanocomposites. Within all the phenomenology associated to antibacterial effects we highlight the possible mechanisms of action. We discuss the differences in the susceptibility of Gram negative and positive bacteria to the antibacterial activity of nanocomposites, and influencing factors. As well, the main applications of copper polymer-metal nanocomposites are described, considering their physical and chemical characteristics. Finally, some commercially available copper-polymer nanocomposites are described. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Evaluation of low copper content antifouling paints containing natural phenolic compounds as bioactive additives.

    Science.gov (United States)

    Pérez, Miriam; García, Mónica; Blustein, Guillermo

    2015-08-01

    Cuprous oxide is the most commonly used biocide in antifouling paints. However, copper has harmful effects not only on the fouling community but also on non-target species. In the current study, we investigated the use of thymol, eugenol and guaiacol in this role combined with small quantities of copper. Phenolic compounds were tested for anti-settlement activity against cyprid larvae of the barnacle Balanus amphitrite and for their toxicity to nauplius larvae. Thymol, eugenol and guaiacol were active for anti-settlement but guaiacol had the disadvantage of being toxic to nauplius larvae. However, all of them showed therapeutic ratio>1. Antifouling paints with thymol (low copper content/thymol, LCP/T), eugenol (low copper content/eugenol, LCP/E) and guaiacol (low copper content/guaiacol, LCP/G) combined with small copper content were formulated for field trials. After 12 months exposure in the sea, statistical analysis revealed that LCP/T and LCP/E paints were the most effective combinations and had similar performances to control paints with high copper content (traditional cuprous oxide based paints). In contrast, LCP/G paint was only partially effective in preventing and inhibiting biofouling and was colonized by some hard and soft foulers. However, this antifouling paint was effective against calcareous tubeworm Hydroides elegans. In the light of various potential applications, thymol, eugenol and guaiacol have thus to be considered in future antifouling formulations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. A copper vapor laser by using a copper-vapor-complex reaction at a low temperature

    OpenAIRE

    Kano, Toshiyuki; Taniguchi, Hiroshi; Saito, Hiroshi

    1987-01-01

    A copper vapor laser performance by using ametal-vapor-complex reaction (Cu+AlBr3) is reported. The laser operation is obtained at a low temperature without externalheating because of the AlBr3 vapors evaporating at a room temperature. The copper vapor laser using this metal-vapor-complex reaction has an advantage of deposition-free of a metallic copper to the laser tube wall, which is different from the copper halide and the organometallic copper lasers.

  5. Gaseous diffusion system

    International Nuclear Information System (INIS)

    Garrett, G.A.; Shacter, J.

    1978-01-01

    A gaseous diffusion system is described comprising a plurality of diffusers connected in cascade to form a series of stages, each of the diffusers having a porous partition dividing it into a high pressure chamber and a low pressure chamber, and means for combining a portion of the enriched gas from a succeeding stage with a portion of the enriched gas from the low pressure chamber of each stage and feeding it into one extremity of the high pressure chamber thereof

  6. Inpainting using airy diffusion

    Science.gov (United States)

    Lorduy Hernandez, Sara

    2015-09-01

    One inpainting procedure based on Airy diffusion is proposed, implemented via Maple and applied to some digital images. Airy diffusion is a partial differential equation with spatial derivatives of third order in contrast with the usual diffusion with spatial derivatives of second order. Airy diffusion generates the Airy semigroup in terms of the Airy functions which can be rewritten in terms of Bessel functions. The Airy diffusion can be used to smooth an image with the corresponding noise elimination via convolution. Also the Airy diffusion can be used to erase objects from an image. We build an algorithm using the Maple package ImageTools and such algorithm is tested using some images. Our results using Airy diffusion are compared with the similar results using standard diffusion. We observe that Airy diffusion generates powerful filters for image processing which could be incorporated in the usual packages for image processing such as ImageJ and Photoshop. Also is interesting to consider the possibility to incorporate the Airy filters as applications for smartphones and smart-glasses.

  7. Prolonging the duration of preventing bacterial adhesion of nanosilver-containing polymer films through hydrophobicity.

    Science.gov (United States)

    Yin, Bing; Liu, Tao; Yin, Yansheng

    2012-12-11

    A superhydrophobic coating composed of silver nanoparticles was developed on copper from fluorinated multilayered polyelectrolyte films to examine its performance in preventing microbial adhesion. Antibacterial and antibiofouling experiments for this novel coating were conducted with SRB. From the disk diffusion tests (for 48 h), it was found that, compared to the traditional coating composed of nanosilver, this novel coating significantly improved antibacterial performance and long-term effectiveness. The oxidation states of the immobilized silver in polyelectrolyte multilayer films were investigated with X-ray photoelectron spectroscopy (XPS), and the stability of the immobilized silver was evaluated through a leaching test. It was found that if silver was exposed to aqueous environments some ionic silver species would be produced and released. The ion release kinetics showed that the duration of sustained release of antibacterial Ag ions from the novel coatings was prolonged, which was why they had more long-term antibacterial performance.

  8. Large single crystals of graphene on melted copper using chemical vapor deposition.

    Science.gov (United States)

    Wu, Yimin A; Fan, Ye; Speller, Susannah; Creeth, Graham L; Sadowski, Jerzy T; He, Kuang; Robertson, Alex W; Allen, Christopher S; Warner, Jamie H

    2012-06-26

    A simple method is presented for synthesizing large single crystal graphene domains on melted copper using atmospheric pressure chemical vapor deposition (CVD). This is achieved by performing the reaction above the melting point of copper (1090 °C) and using a molybdenum or tungsten support to prevent balling of the copper from dewetting. By controlling the amount of hydrogen during growth, individual single crystal domains of monolayer graphene greater than 200 μm are produced within a continuous film. Stopping growth before a complete film is formed reveals individual hexagonal domains of graphene that are epitaxially aligned in their orientation. Angular resolved photoemission spectroscopy is used to show that the graphene grown on copper exhibits a linear dispersion relationship and no sign of doping. HRTEM and electron diffraction reveal a uniform high quality crystalline atomic structure of monolayer graphene.

  9. Effects of vacuum processing erbium dideuteride/ditritide films deposited on chromium underlays on copper substrates

    International Nuclear Information System (INIS)

    Provo, J.L.

    1978-01-01

    Thin films of erbium dideuteride/ditritide were experimentally produced on chromium underlays deposited on copper substrates. The chromium underlay is required to prevent erbium occluder/copper substrate alloying which inhibits hydriding. Data taken has shown that vacuum processing affects the erbium/chromium/copper interaction. With an in situ process in which underlay/occluder films are vacuum deposited onto copper substrates and hydrided with no air exposure between these steps, data indicates a minimum of 1500A of chromium is required for optimum hydriding. If films are vacuum deposited as above and air-exposed before hydriding, a minimum of 3000A of chromium was shown to be required for equivalent hydriding. Data suggests that the activation step (600 0 C for 1 hour) required for hydriding the film of the second type is responsible for the difference observed. Such underlay thickness parameters are important, with regard to heat transfer considerations in thin hydride targets used for neutron generation

  10. on THICKNESS OF COPPER (|) OXIDE

    African Journals Online (AJOL)

    2006-12-20

    Dec 20, 2006 ... semiconductor devices. The oxide is. Observed to be an attractive starting material for the production of solar cells for low cost terrestrial conversion of solar energy to electricity. Copper (I) oxide is one Of the earliest known photovoltaic materials and the first in which the photovOltaic effect was successfully ...

  11. A Study of Protection of Copper Alloys

    International Nuclear Information System (INIS)

    Kim, E. A.; Kim, S. H.; Kim, C. R.

    1974-01-01

    Volatile treatment of high capacity boiler water with hydrazine and ammonia is studied. Ammonia comes from the decomposition of excess hydrazine injected to treat dissolved oxygen. Ammonia is also injected for the control of pH. To find an effect of such ammonia on the copper alloy, the relations between pH and iron, and ammonia and copper are studied. Since the dependence of corrosion of iron on pH differs from that of copper, a range of pH was selected experimentally to minimize the corrosion rates of both copper and iron. Corrosion rates of various copper alloys are also compared

  12. Chronic copper toxicity in a dairy herd

    OpenAIRE

    Perrin, David J.; Schiefer, H. Bruno; Blakley, Barry R.

    1990-01-01

    The addition of excessive copper to a commercially prepared dairy ration caused chronic copper toxicity in a dairy herd. A formulation error by a feed company resulted in copper levels of 800 to 1,000 mg/kg in the “as fed concentrate,” amounting to about 400-500 mg copper/kg of the whole ration. Five animals died with typical signs of acute copper toxicity, including intravascular hemolysis and methemoglobinemia. A further 39 cows died on the farm from a combination of debilitation and second...

  13. Oxygen Diffusion in Titanite

    Science.gov (United States)

    Zhang, X. Y.; Cherniak, D. J.; Watson, E. B.

    2004-05-01

    Oxygen diffusion in natural and synthetic single-crystal titanite was characterized under both dry and water-present conditions. For the dry experiments, pre-polished titanite samples were packed in 18O-enriched quartz powder inside Ag-Pd capsules, along with an FMQ buffer assemblage maintained physically separate by Ag-Pd strips. The sealed Ag-Pd capsules were themselves sealed inside evacuated silica glass tubes and run at 700-1050° C and atmospheric pressure for durations ranging from 1 hour to several weeks. The hydrothermal experiments were conducted by encapsulating polished titanite crystals with 18O enriched water and running them at 700-900° C and 10-160MPa in standard cold-seal pressure vessels for durations of 1 day to several weeks. Diffusive uptake profiles of 18O were measured in all cases by nuclear reaction analysis (NRA) using the 18O (p,α ) 15N reaction. For the experiments on natural crystals, under both dry and hydrothermal conditions, two mechanisms could be recognized responsible for oxygen diffusion. The diffusion profiles showed two segments: a steep one close to the initial surface attributed to self-diffusion in the titanite lattice; and a "tail" reaching deeper into the sample attributable to diffusion in a "fast path" such as sub-grain boundaries or dislocations. For the dry experiments, the following Arrhenius relation was obtained: D{dry lattice} = 2.6×10-8exp (-275 kJmol-1/RT) m2/s Under wet conditions at PH2O = 100MPa, Oxygen diffusion conforms to the following Arrehenius relation: D{wet lattice} = 9.7× 10-13exp (-174 kJmol-1/RT) m2/s Oxygen diffusivity shows only a slight dependence on water pressure at the following conditions we explored: temperatures 800° C, PH2O = 10-160MPa, and 880° C, PH2O =10-100MPa. For diffusive anisotropy, we explored it only at hydrothermal conditions, and no diffusive anisotropy was observed. Like many other silicates, titanite shows lower activation energy for oxygen diffusion in the presence of

  14. Laryngeal Neuropathy in Adult Goats With Copper Deficiency.

    Science.gov (United States)

    Sousa, R F A; Almeida, V M; Neto, J E; Nascimento, C W A; Medeiros, G X; Medeiros, R M T; Riet-Correa, F; Mendonça, F S

    2017-07-01

    The aim of this study was to elucidate the cause of a neurological syndrome characterized by stridor in adult goats with clinical signs of copper deficiency. The main clinical signs consisted of apathy, emaciation, pale mucous membranes, mucous nasal discharge, dyspnea, severe achromotrichia, diffuse alopecia, torpor, ataxia, and stridor. When the goats were forced to move, the stridor increased. In a herd of 194 Toggenburg goats, 10 adult goats with clinical signs of copper deficiency were removed from the herd and divided into 2 groups: group 1, which consisted of 4 nannies and 1 buck with stridor, and group 2, which consisted of 4 nannies and 1 buck without stridor. Group 3, used as a control, consisted of 5 adult goats from another flock without any clinical signs of disease. The mean serum copper concentrations were 1.3 ± 0.3 μmol/L in group 1, 8.1 ± 1.1 μmol/L in group 2, and 11.3 ± 2.2 μmol/L in group 3. The mean serum iron concentrations were 42.3 ± 14.2 μmol/L in group 1, 39.1 ± 8.2 μmol/L in group 2, and 20.6 ± 6.1 μmol/L in group 3. The main histological lesions in goats from group 1 were axonal degeneration of the recurrent laryngeal nerves and atrophy of the muscles of vocal folds and of the dorsal cricoarytenoid and right and left cricothyroid muscles. Goats with ataxia had neuronal degeneration and necrosis of cerebellar Purkinje cells and of the cranial cervical ganglion. We concluded that the stridor was caused by axonal degeneration of the recurrent laryngeal nerves due to the severe copper deficiency.

  15. Controlling Copper Electrochemical Deposition (ECD)

    Science.gov (United States)

    West, Michael; McDonald, Robert; Anderson, Marc; Kingston, Skip; Mui, Rudy

    2003-09-01

    The implementation of copper processing in semiconductor manufacturing has resulted in major process development and manufacturing challenges. A fundamental understanding of the copper plating processes used in manufacturing has been limited by the lack of in-line methods for direct measurement and control of process chemistry. Plating bath chemistry adjustments and change-out frequencies are currently determined using a combination of indirect electrochemical monitoring techniques, off-line analyses of wafer metrology and analytical lab measurements. There have been a number of industry reports of major process startup delays, yield management problems and reliability issues as a result of these difficulties. A new in-process mass spectrometry (IPMS) approach enables automated, real-time measurement of both the inorganic components and organic additives in the copper electroplating chemistry as they change during production. The tool is not only capable of real time direct quantification of the copper, chloride, pH, and organic additives in the plating bath, but can also monitor additive breakdown byproducts as they occur during the production process. These breakdown products, as well as changes in the original bath constituent composition can be expected to have a major impact on process performance. We are now in the process of measuring longer term plating bath stability and chemistry changes in prototype applications in semiconductor fab manufacturing environments. The first results demonstrate improved process understanding and the potential for greatly improved process control. We will discuss the technical challenges that were successfully addressed in developing the IPMS capability for application to the copper plating process and the initial process data subsequently obtained.

  16. Modelling of Innovation Diffusion

    Directory of Open Access Journals (Sweden)

    Arkadiusz Kijek

    2010-01-01

    Full Text Available Since the publication of the Bass model in 1969, research on the modelling of the diffusion of innovation resulted in a vast body of scientific literature consisting of articles, books, and studies of real-world applications of this model. The main objective of the diffusion model is to describe a pattern of spread of innovation among potential adopters in terms of a mathematical function of time. This paper assesses the state-of-the-art in mathematical models of innovation diffusion and procedures for estimating their parameters. Moreover, theoretical issues related to the models presented are supplemented with empirical research. The purpose of the research is to explore the extent to which the diffusion of broadband Internet users in 29 OECD countries can be adequately described by three diffusion models, i.e. the Bass model, logistic model and dynamic model. The results of this research are ambiguous and do not indicate which model best describes the diffusion pattern of broadband Internet users but in terms of the results presented, in most cases the dynamic model is inappropriate for describing the diffusion pattern. Issues related to the further development of innovation diffusion models are discussed and some recommendations are given. (original abstract

  17. Thermal diffusion (1963)

    International Nuclear Information System (INIS)

    Lemarechal, A.

    1963-01-01

    This report brings together the essential principles of thermal diffusion in the liquid and gaseous phases. The macroscopic and molecular aspects of the thermal diffusion constant are reviewed, as well as the various measurement method; the most important developments however concern the operation of the CLUSIUS and DICKEL thermo-gravitational column and its applications. (author) [fr

  18. Diffusion Based Photon Mapping

    DEFF Research Database (Denmark)

    Schjøth, Lars; Olsen, Ole Fogh; Sporring, Jon

    2006-01-01

    . To address this problem we introduce a novel photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way we preserve the important illumination features......, while eliminating noise. We call our method diffusion based photon mapping....

  19. Superhydrophobic Copper Surfaces with Anticorrosion Properties Fabricated by Solventless CVD Methods.

    Science.gov (United States)

    Vilaró, Ignasi; Yagüe, Jose L; Borrós, Salvador

    2017-01-11

    Due to continuous miniaturization and increasing number of electrical components in electronics, copper interconnections have become critical for the design of 3D integrated circuits. However, corrosion attack on the copper metal can affect the electronic performance of the material. Superhydrophobic coatings are a commonly used strategy to prevent this undesired effect. In this work, a solventless two-steps process was developed to fabricate superhydrophobic copper surfaces using chemical vapor deposition (CVD) methods. The superhydrophobic state was achieved through the design of a hierarchical structure, combining micro-/nanoscale domains. In the first step, O 2 - and Ar-plasma etchings were performed on the copper substrate to generate microroughness. Afterward, a conformal copolymer, 1H,1H,2H,2H-perfluorodecyl acrylate-ethylene glycol diacrylate [p(PFDA-co-EGDA)], was deposited on top of the metal via initiated CVD (iCVD) to lower the surface energy of the surface. The copolymer topography exhibited a very characteristic and unique nanoworm-like structure. The combination of the nanofeatures of the polymer with the microroughness of the copper led to achievement of the superhydrophobic state. AFM, SEM, and XPS were used to characterize the evolution in topography and chemical composition during the CVD processes. The modified copper showed water contact angles as high as 163° and hysteresis as low as 1°. The coating withstood exposure to aggressive media for extended periods of time. Tafel analysis was used to compare the corrosion rates between bare and modified copper. Results indicated that iCVD-coated copper corrodes 3 orders of magnitude slower than untreated copper. The surface modification process yielded repeatable and robust superhydrophobic coatings with remarkable anticorrosion properties.

  20. Corrosion and inhibition of copper in hydrocarbon solution on a molecular level investigated using neutron reflectometry and XPS

    International Nuclear Information System (INIS)

    Welbourn, Rebecca J.L.; Truscott, C.L.; Skoda, M.W. A.; Zarbakhsh, A.; Clarke, S.M.

    2017-01-01

    Highlights: • Corrosion of CuO by sulphur in oil is inhibited by organic amine but not thiol. • Neutron reflection gives insight into the layer structure and composition. • The most well packed organic layer does not give the best corrosion protection. • Organic thiol selectively removes Cu(II) to leave a Cu(I) surface. - Abstract: The behaviour and molecular structure of three organic additives adsorbed from oil onto a copper surface rich in copper (II) oxide is presented. The variation in the ability of these three agents to prevent corrosion of the copper oxide surface by exposure to sulphur is also included. A combination of visible observations, X-ray photoelectron spectroscopy (XPS) and neutron reflection (NR) are used to characterise both the adsorbed layer and underlying copper oxide. The model additives are chosen to represent ‘effective’, ‘intermediate’ and ‘ineffective’ inhibitors for copper.

  1. Serum copper and ceruloplasmin levels and urinary copper excretion in thermal injury.

    Science.gov (United States)

    Boosalis, M G; McCall, J T; Solem, L D; Ahrenholz, D H; McClain, C J

    1986-12-01

    Conflicting reports regarding copper status in thermal injury patients have been published. We determined serial serum-copper and serum-ceruloplasmin levels and 24-h urinary excretion of copper in 23 patients with second- and third-degree thermal burns. Throughout hospitalization, mean serum-copper concentration was significantly depressed; lowest levels were found in patients with greater than 40% total body surface area burns. Serum ceruloplasmin was also depressed, an unexpected finding because this protein is a positive acute-phase reactant poststress. Mean urinary excretion of copper was elevated, reaching 2.5 times the upper limit of normal 2 wk postburn. Depressed serum-copper levels paralleled the serum-ceruloplasmin levels rather than the increased urinary-copper losses. Further studies are required to determine the mechanism(s) of this altered copper metabolism and whether physiological or biochemical evidence of copper deficiency accompanies the observed hypocupremia.

  2. Diffusion within alpha-CuI studied using ab initio molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Mohn, Chris E [Laboratoire des Colloides, Verres et Nanomateriaux, UMR 5587, Universite Montpellier II-CNRS, 34095 Montpellier (France); Stoelen, Svein [Department of Chemistry and Centre for Materials Science and Nanotechnology, University of Oslo, PO Box 1033 Blindern, N-0315 Oslo (Norway); Hull, Stephen, E-mail: chrism@kjemi.uio.n [ISIS Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire 0X11 0QX (United Kingdom)

    2009-08-19

    The structure and dynamics of superionic alpha-CuI are studied in detail by means of ab initio Born-Oppenheimer molecular dynamics simulations. The extreme cation disorder and a soft immobile face centred cubic sublattice are evident from the highly diffuse atomic density profiles. The Cu-Cu pair distribution function and distribution of Cu-I-Cu bond angles possess distinct peaks at 2.6 A and 60 deg. respectively, which are markedly lower than the values expected from the average cationic density, pointing to the presence of pronounced short-range copper-copper correlations. Comparison with lattice static calculations shows that these correlations and the marked shift in the cationic density profile in the (111) directions are associated with a locally distorted cation sublattice, and that the movements within the tetrahedral cavities involve rapid jumps into and out of shallow basins on the system potential energy surface. On average, the iodines are surrounded by three coppers within their first coordination shell, with the fourth copper being located in a transition zone between two neighbouring iodine cavities. However, time-resolved analysis reveals that the local structure actually involves a mixture of threefold-, fourfold- and fivefold-coordinated iodines. Examination of the ionic trajectories shows that the copper ions jump rapidly to nearest neighbouring tetrahedral cavities (aligned in the (100) directions) following a markedly curved trajectory and often involving short-lived ({approx}1 ps) interstitial positions. The nature of the correlated diffusion underlying the unusually high fraction of coppers with short residence time can be attributed to the presence of a large number of 'unsuccessful' jumps and the likelihood of cooperative motion of pairs of coppers. The calculated diffusion coefficient at 750 K, D{sup Cu} = 2.8 x 10{sup -5} cm{sup 2} s{sup -1}, is in excellent agreement with that found experimentally.

  3. Diffuse ceiling ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen

    Diffuse ceiling ventilation is an innovative ventilation concept where the suspended ceiling serves as air diffuser to supply fresh air into the room. Compared with conventional ventilation systems, diffuse ceiling ventilation can significantly reduce or even eliminate draught risk due to the low...... momentum supply. In addition, this ventilation system uses a ceiling plenum to deliver air and requires less energy consumption for air transport than full-ducted systems. There is a growing interest in applying diffuse ceiling ventilation in offices and other commercial buildings due to the benefits from...... both thermal comfort and energy efficient aspects. The present study aims to characterize the air distribution and thermal comfort in the rooms with diffuse ceiling ventilation. Both the stand-alone ventilation system and its integration with a radiant ceiling system are investigated. This study also...

  4. Atomic diffusion in stars

    CERN Document Server

    Michaud, Georges; Richer, Jacques

    2015-01-01

    This book gives an overview of atomic diffusion, a fundamental physical process, as applied to all types of stars, from the main sequence to neutron stars. The superficial abundances of stars as well as their evolution can be significantly affected. The authors show where atomic diffusion plays an essential role and how it can be implemented in modelling.  In Part I, the authors describe the tools that are required to include atomic diffusion in models of stellar interiors and atmospheres. An important role is played by the gradient of partial radiative pressure, or radiative acceleration, which is usually neglected in stellar evolution. In Part II, the authors systematically review the contribution of atomic diffusion to each evolutionary step. The dominant effects of atomic diffusion are accompanied by more subtle effects on a large number of structural properties throughout evolution. One of the goals of this book is to provide the means for the astrophysicist or graduate student to evaluate the importanc...

  5. Diffusing Best Practices

    DEFF Research Database (Denmark)

    Pries-Heje, Jan; Baskerville, Richard

    2014-01-01

    resulting from the design were two-day training workshops conceptually anchored to TBP. The design theory was evaluated through execution of eight diffusion workshops involving three different groups in the same company. The findings indicate that the match between the practice and the context materialized...... in the successful techniques in one context. While the value for other contexts is unproven, knowledge of best practices circulates under an assumption that the practices will usefully self-diffuse through innovation and adoption in other contexts. We study diffusion of best practices using a design science...... approach. The study context is a design case in which an organization desires to diffuse its best practices across different groups. The design goal is embodied in organizational mechanisms to achieve this diffusion. The study used Theory of Planned Behavior (TPB) as a kernel theory. The artifacts...

  6. Degenerate nonlinear diffusion equations

    CERN Document Server

    Favini, Angelo

    2012-01-01

    The aim of these notes is to include in a uniform presentation style several topics related to the theory of degenerate nonlinear diffusion equations, treated in the mathematical framework of evolution equations with multivalued m-accretive operators in Hilbert spaces. The problems concern nonlinear parabolic equations involving two cases of degeneracy. More precisely, one case is due to the vanishing of the time derivative coefficient and the other is provided by the vanishing of the diffusion coefficient on subsets of positive measure of the domain. From the mathematical point of view the results presented in these notes can be considered as general results in the theory of degenerate nonlinear diffusion equations. However, this work does not seek to present an exhaustive study of degenerate diffusion equations, but rather to emphasize some rigorous and efficient techniques for approaching various problems involving degenerate nonlinear diffusion equations, such as well-posedness, periodic solutions, asympt...

  7. Variations of serum copper values in pregnancy

    Directory of Open Access Journals (Sweden)

    Vukelić Jelka

    2012-01-01

    Full Text Available Introduction. Copper is essential micronutrient and has an important role in the human body. The serum copper increases during pregnancy and is doubled at full term. Lower levels of serum copper in pregnancy are connected with some pathological conditions. Objective. The aim of this study was to estimate the levels of serum copper in normal and pathological pregnancies, comparing them with values of serum copper in non-pregnant women, to determine if serum copper is lower in some pathological pregnancies and if this is of some importance. Methods. A total of 2170 plasma samples for copper analyses were made in the following groups: healthy non-pregnant women; healthy pregnant women from the 5th-40th gestational week, during the first delivery stage and during the first three postpartum weeks, in pregnant women with habitual abortion, imminent abortion, abortion in progress, missed abortion (9th-24th weeks, missed labour and premature rupture of membranes (29th-40th weeks. Levels of serum copper were determined by colorimetric technique of bathocuproin with disulphate as a chromogen. Results. Serum copper values in non-pregnant women range from 11.6-25.8 μmol/L. In healthy pregnant women, there is a constant trend of the increase of serum copper. The mean serum copper values revealed three significant peaks at the 22nd, 27th and 35th gestational week. Serum copper values in the patients with some pathological pregnancies in relation to the serum copper values of the healthy pregnant women were significantly lower. Conclusion. Serum copper values can be used as an indicator of some pathological pregnancies.

  8. Oxygen diffusion in monazite

    Science.gov (United States)

    Cherniak, D. J.; Zhang, X. Y.; Nakamura, M.; Watson, E. B.

    2004-09-01

    We report measurements of oxygen diffusion in natural monazites under both dry, 1-atm conditions and hydrothermal conditions. For dry experiments, 18O-enriched CePO4 powder and monazite crystals were sealed in Ag-Pd capsules with a solid buffer (to buffer at NNO) and annealed in 1-atm furnaces. Hydrothermal runs were conducted in cold-seal pressure vessels, where monazite grains were encapsulated with 18O-enriched water. Following the diffusion anneals, oxygen concentration profiles were measured with Nuclear Reaction Analysis (NRA) using the reaction 18O(p,α)15N. Over the temperature range 850-1100 °C, the Arrhenius relation determined for dry diffusion experiments on monazite is given by: Under wet conditions at 100 MPa water pressure, over the temperature range 700-880 °C, oxygen diffusion can be described by the Arrhenius relationship: Oxygen diffusion under hydrothermal conditions has a significantly lower activation energy for diffusion than under dry conditions, as has been found the case for many other minerals, both silicate and nonsilicate. Given these differences in activation energies, the differences between dry and wet diffusion rates increase with lower temperatures; for example, at 600 °C, dry diffusion will be more than 4 orders of magnitude slower than diffusion under hydrothermal conditions. These disparate diffusivities will result in pronounced differences in the degree of retentivity of oxygen isotope signatures. For instance, under dry conditions (presumably rare in the crust) and high lower-crustal temperatures (∼800 °C), monazite cores of 70-μm radii will preserve O isotope ratios for about 500,000 years; by comparison, they would be retained at this temperature under wet conditions for about 15,000 years.

  9. Effect of copper loading on copper-ceria catalysts performance in CO selective oxidation for fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Ayastuy, J.L.; Gurbani, A.; Gonzalez-Marcos, M.P.; Gutierrez-Ortiz, M.A. [Departamento de Ingenieria Quimica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco/EHU, E-48080 Bilbao (Spain); Unidad Asociada ' ' Tecnologias Quimicas para la Sostenibilidad Ambiental' ' , CSIC-UPV/EHU (Spain)

    2010-02-15

    Copper-ceria catalysts with three different Cu loadings (1, 7 and 15 wt%) were prepared by incipient wet impregnation, dried at 120 C and calcined in air at 500 C. The as-prepared catalysts were characterized by XRD, BET, Diffuse Reflectance Spectroscopy (DRS-UV-visible), Raman spectroscopy, CO and H{sub 2}-TPR, CO-TPR, CO-TPD and Oxygen Storage Capacity (OSC) measurements (with CO and O{sub 2} concentration step-changes). The results indicated a good dispersion of copper for catalysts with 1 and 7 wt% Cu; however, bulk CuO was present for catalyst with 15 wt% Cu loading. Catalyst with 7 wt% Cu was observed to have very high capacity to release lattice oxygen to oxidize CO at low temperature. Activity results for CO oxidation in the absence and in the presence of 60% H{sub 2}, demonstrated a very similar performance for catalysts with 7 and 15 wt% Cu (both with T{sub 100} = 112 C), and much better than that of catalyst loaded with 1 wt% Cu. Catalyst with 7 wt% of copper shows very high activity (100% in a wide temperature window) and selectivity (higher than 85%), which makes an attractive for its use in purification of hydrogen for fuel cell applications. The presence of a mixture of CO{sub 2} and H{sub 2}O inhibited catalyst activity, with CuO/CeO{sub 2} catalyst with 7 wt% Cu exhibiting the best performance in the overall reaction temperature range. This could be attributed to the presence of highly disperse copper, only part of it in deep interaction with ceria. The effect of O{sub 2}/CO ratio ({lambda}) and the potential reversibility of the inhibitory effect of CO{sub 2} and H{sub 2}O were also investigated. (author)

  10. A Plasmodium falciparum copper-binding membrane protein with copper transport motifs

    Directory of Open Access Journals (Sweden)

    Choveaux David L

    2012-11-01

    Full Text Available Abstract Background Copper is an essential catalytic co-factor for metabolically important cellular enzymes, such as cytochrome-c oxidase. Eukaryotic cells acquire copper through a copper transport protein and distribute intracellular copper using molecular chaperones. The copper chelator, neocuproine, inhibits Plasmodium falciparum ring-to-trophozoite transition in vitro, indicating a copper requirement for malaria parasite development. How the malaria parasite acquires or secretes copper still remains to be fully elucidated. Methods PlasmoDB was searched for sequences corresponding to candidate P. falciparum copper-requiring proteins. The amino terminal domain of a putative P. falciparum copper transport protein was cloned and expressed as a maltose binding fusion protein. The copper binding ability of this protein was examined. Copper transport protein-specific anti-peptide antibodies were generated in chickens and used to establish native protein localization in P. falciparum parasites by immunofluorescence microscopy. Results Six P. falciparum copper-requiring protein orthologs and a candidate P. falciparum copper transport protein (PF14_0369, containing characteristic copper transport protein features, were identified in PlasmoDB. The recombinant amino terminal domain of the transport protein bound reduced copper in vitro and within Escherichia coli cells during recombinant expression. Immunolocalization studies tracked the copper binding protein translocating from the erythrocyte plasma membrane in early ring stage to a parasite membrane as the parasites developed to schizonts. The protein appears to be a PEXEL-negative membrane protein. Conclusion Plasmodium falciparum parasites express a native protein with copper transporter characteristics that binds copper in vitro. Localization of the protein to the erythrocyte and parasite plasma membranes could provide a mechanism for the delivery of novel anti-malarial compounds.

  11. Uptake and internalisation of copper by three marine microalgae: comparison of copper-sensitive and copper-tolerant species.

    Science.gov (United States)

    Levy, Jacqueline L; Angel, Brad M; Stauber, Jennifer L; Poon, Wing L; Simpson, Stuart L; Cheng, Shuk Han; Jolley, Dianne F

    2008-08-29

    Although it has been well established that different species of marine algae have different sensitivities to metals, our understanding of the physiological and biochemical basis for these differences is limited. This study investigated copper adsorption and internalisation in three algal species with differing sensitivities to copper. The diatom Phaeodactylum tricornutum was particularly sensitive to copper, with a 72-h IC50 (concentration of copper to inhibit growth rate by 50%) of 8.0 microg Cu L(-1), compared to the green algae Tetraselmis sp. (72-h IC50 47 microg Cu L(-1)) and Dunaliella tertiolecta (72-h IC50 530 microg Cu L(-1)). At these IC50 concentrations, Tetraselmis sp. had much higher intracellular copper (1.97+/-0.01 x 10(-13)g Cu cell(-1)) than P. tricornutum (0.23+/-0.19 x 10(-13)g Cu cell(-1)) and D. tertiolecta (0.59+/-0.05 x 10(-13)g Cu cell(-1)), suggesting that Tetraselmis sp. effectively detoxifies copper within the cell. By contrast, at the same external copper concentration (50 microg L(-1)), D. tertiolecta appears to better exclude copper than Tetraselmis sp. by having a slower copper internalisation rate and lower internal copper concentrations at equivalent extracellular concentrations. The results suggest that the use of internal copper concentrations and net uptake rates alone cannot explain differences in species-sensitivity for different algal species. Model prediction of copper toxicity to marine biota and understanding fundamental differences in species-sensitivity will require, not just an understanding of water quality parameters and copper-cell binding, but also further knowledge of cellular detoxification mechanisms.

  12. Fluorescent copper(II complexes: The electron transfer mechanism, interaction with bovine serum albumin (BSA and antibacterial activity

    Directory of Open Access Journals (Sweden)

    Madhumita Hazra

    2017-01-01

    Full Text Available Dinuclear copper(II complexes with formula [Cu2(L2(N32] (1 and [Cu2(L2(NCS2] (2 HL = (1-[(3-methyl-pyridine-2-ylimino-methyl]-naphthalen-2-ol were synthesized by controlling the molar ratio of Cu(OAC2·6H2O, HL, sodium azide (1 and ammonium thiocyanate (2. The end on bridges appear exclusively in azide and thiocyanate to copper complexes. The electron transfer mechanism of copper(II complexes is examined by cyclic voltammetry indicating copper(II complexes are Cu(II/Cu(I couple. The interactions of copper(II complexes towards bovine serum albumin (BSA were examined with the help of absorption and fluorescence spectroscopic tools. We report a superficial solution-based route for the synthesis of micro crystals of copper complexes with BSA. The antibacterial activity of the Schiff base and its copper complexes were investigated by the agar disc diffusion method against some species of pathogenic bacteria (Escherichia coli, Vibrio cholerae, Streptococcus pneumonia and Bacillus cereus. It has been observed that the antibacterial activity of all complexes is higher than the ligand.

  13. Investigation of influence of Co60 γ - quanta to recombination properties of the copper doped silicon

    International Nuclear Information System (INIS)

    Makhmudov, Sh.; Karimov, M.

    2006-01-01

    Full text: The aim of the work is to study the influence of post-thermal diffusion and γ- irradiation to the recombination properties of rapid and slow cooled copper doped silicon. As an initial material the n-Si with ∼5 and 2000 Ohm·cm specific resistance was used. The dislocation density is taken to be ∼10 4 cm -2 . Doping of silicon by copper carried out in the temperature range of 1050/1300 deg C with succeeding I and II type cooling those rapidity was 30-40 deg/min (I type samples) and 250-300 deg/min (II type samples). At the same time it is investigated n-Si samples which were under analogically heat treatment but without copper doping. The life-time of the charge carriers was determined using the stationary photoconductivity method. A new series of results are obtained. They are: it is revealed that by increasing of the copper concentration in p-Si and n-Si the magnitude of t increases in comparison with control silicon. The effect is explained by intensification of micro-heterogeneity on conductivity in the compensation process of the material. It is shown that by electro physic and recombination properties in the I type n-Si and p-Si samples the thermo stability in 350 - 500 deg C is observed. It is discovered that the changing of (τ/τ 0 ) appreciably differs one from other in I and II type samples after irradiation by γ- quanta. In the rapid cooled samples τ is more radiation stable than slow cooled samples up to dose ∼ 2 ·10 8 R and this effect is explained with a high concentration of electro active copper atoms in the samples. Last ones connected with post diffusion cooling. At that by increasing of copper atoms concentration the radiation stability increases. (author)

  14. Modification of surface layers of copper under the action of the volumetric discharge initiated by an avalanche electron beam in nitrogen and CO2 at atmospheric pressure

    Science.gov (United States)

    Shulepov, M. A.; Akhmadeev, Yu. Kh.; Tarasenko, V. F.; Kolubaeva, Yu. A.; Krysina, O. V.; Kostyrya, I. D.

    2011-05-01

    The results of experimental investigations of the action of the volumetric discharge initiated by an avalanche electron beam on the surface of copper specimens are presented. The volumetric (diffuse) discharge in nitrogen and CO2 at atmospheric pressure was initiated by applying high voltage pulses of nanosecond duration to a tubular foil cathode. It has been found that the treatment of a copper surface by this type of discharge increases the hardness of the surface layer due to oxidation.

  15. Review of supercontainer copper shell-bentonite interactions and possible effects on buffer performance for the KBS-3H design

    International Nuclear Information System (INIS)

    King, F.; Wersin, P.

    2014-03-01

    A review is presented of the possible impact of the corrosion of a copper supercontainer shell on the performance of the bentonite buffer. The review is presented in two parts; first an assessment of the likely corrosion behaviour of the copper shell, including an assessment of the amount and speciation of copper corrosion products, and, second an assessment of the possible interactions of these copper corrosion products with the bentonite and the consequences for the buffer performance. The corrosion behaviour of oxygen-free copper in compacted bentonite is reviewed, including the effects of a possible lower-density region at the buffer-rock interface initially. Corrosion occurs under both aerobic conditions, due to the initial O 2 trapped in the bentonite and O 2 in the air or water-filled gap at the buffer/rock interface, and anaerobic conditions, due to sulphide present in the groundwater and that possibly produced by microbial activity in the bentonite. The reaction mechanism, the nature of the dissolved and precipitated corrosion products, and the evolution of the corrosion behaviour with time are discussed with reference to groundwater conditions at both Olkiluoto and Forsmark. Various interactions between the copper corrosion products (Cu(II) and Cu(I) species) and bentonite are considered, including diffusion and sorption and the incorporation of Cu into the bentonite. The available literature information on these processes is first reviewed and then this knowledge is used to predict the likely behaviour in a KBS-3H-style repository. Based on the information currently available, it is concluded that the corrosion of a copper supercontainer shell will only affect the bentonite within a distance of a few cm of the original location of the shell. Eventually, the copper shell will corrode to form an insoluble precipitate layer of Cu 2 S approximately 2-3 times the volume of the original shell. Bentonite within a few cm of this layer of precipitate may also

  16. Electrochemical in-situ impregnation of wood using a copper nail as source for copper

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Block, Thomas; Nymark, Morten

    2011-01-01

    A new method for copper impregnation of wood in structures was suggested and tested in laboratory scale with specimen of new pine sapwood. A copper nail and a steel screw were placed in the wood, and an electric direct current field was applied, so the copper nail was anode and the screw...... was cathode. At the anode, copper ions were generated. The copper ions were transported into the wood by electromigration (movement of ions in an applied electric field) towards the cathode, and a volume between the two electrodes was thereby impregnated. Copper also moved to a lesser degree in the opposite...

  17. Ammonia leaching of copper smelter dust and precipitation as copper sulphide

    International Nuclear Information System (INIS)

    Morales, A.; Hevia, J. F.; Cifuentes, G.

    2009-01-01

    The effect of ammonia on the leaching of copper smelter dust and copper precipitation from these solutions as sulphide using sulfur and sulfur dioxide was studied. The precipitation was done in ammoniacal media because this solution produced more satisfactory results at room temperature that a sulphuric media. A solid was precipitated containing 60 % of copper of the dust smelter. The other waste generated contained around 80 % of the arsenic of the original copper smelter dust. Based on the preliminary results obtained in this work it will propose a procedure for the recovery of copper as sulphide from copper smelter dust with parallel confinement of arsenic. (Author) 14 refs.

  18. Diffusion of sulfuric acid in protective organic coatings

    DEFF Research Database (Denmark)

    Wang, Ting; Møller, Victor Buhl; Dam-Johansen, Kim

    Organic protective coatings and linings are widely used to prevent corrosion in industrial processes. However, the permeation of aggressive chemicals through coatings can induce failures. These are described in the literature, but rarely quantified. To measure the diffusion rates of aggressive...... chemicals through organic coatings, a diffusion cell was designed. The diffusion cell designed is simple, small and suitable for scaling up to a battery of cells. A concentration profile of H3O+ through epoxy coatings was achieved for sulfuric acid aqueous solutions, which can be used to estimate diffusion...

  19. Dissolution characteristics of sericite in chalcopyrite bioleaching and its effect on copper extraction

    Science.gov (United States)

    Dong, Ying-bo; Li, Hao; Lin, Hai; Zhang, Yuan

    2017-04-01

    The effects of sericite particle size, rotation speed, and leaching temperature on sericite dissolution and copper extraction in a chalcopyrite bioleaching system were examined. Finer particles, appropriate temperature and rotation speed for Acidithiobacillus ferrooxidans resulted in a higher Al3+ dissolution concentration. The Al3+ dissolution concentration reached its highest concentration of 38.66 mg/L after 48-d leaching when the sericite particle size, temperature, and rotation speed were -43 μm, 30°C, and 160 r/min, respectively. Meanwhile, the sericite particle size, rotation speed, and temperature can affect copper extraction. The copper extraction rate is higher when the sericite particle size is finer. An appropriately high temperature is favorable for copper leaching. The dissolution of sericite fitted the shrinking core model, 1-(2/3) α-(1- α)2/3 = k 1 t, which indicates that internal diffusion is the decision step controlling the overall reaction rate in the leaching process. Scanning electron microscopy analysis showed small precipitates covered on the surface of sericite after leaching, which increased the diffusion resistance of the leaching solution and dissolved ions.

  20. Friction Stir Processing of Copper-Coated SiC Particulate-Reinforced Aluminum Matrix Composite

    Directory of Open Access Journals (Sweden)

    Chih-Wei Huang

    2018-04-01

    Full Text Available In the present work, we proposed a novel friction stir processing (FSP to produce a locally reinforced aluminum matrix composite (AMC by stirring copper-coated SiC particulate reinforcement into Al6061 alloy matrix. Electroless-plating process was applied to deposit the copper surface coating on the SiC particulate reinforcement for the purpose of improving the interfacial adhesion between SiC particles and Al matrix. The core-shell SiC structure provides a layer for the atomic diffusion between aluminum and copper to enhance the cohesion between reinforcing particles and matrix on one hand, the dispersion of fine copper in the Al matrix during FSP provides further dispersive strengthening and solid solution strengthening, on the other hand. Hardness distribution and tensile results across the stir zone validated the novel concept in improving the mechanical properties of AMC that was realized via FSP. Optical microscope (OM and Transmission Electron Microscopy (TEM investigations were conducted to investigate the microstructure. Energy dispersive spectrometer (EDS, electron probe micro-analyzer (EPMA, and X-ray diffraction (XRD were explored to analyze the atomic inter-diffusion and the formation of intermetallic at interface. The possible strengthening mechanisms of the AMC containing Cu-coated SiC particulate reinforcement were interpreted. The concept of strengthening developed in this work may open a new way of fabricating of particulate reinforced metal matrix composites.

  1. Canine Models for Copper Homeostasis Disorders

    Directory of Open Access Journals (Sweden)

    Xiaoyan Wu

    2016-02-01

    Full Text Available Copper is an essential trace nutrient metal involved in a multitude of cellular processes. Hereditary defects in copper metabolism result in disorders with a severe clinical course such as Wilson disease and Menkes disease. In Wilson disease, copper accumulation leads to liver cirrhosis and neurological impairments. A lack in genotype-phenotype correlation in Wilson disease points toward the influence of environmental factors or modifying genes. In a number of Non-Wilsonian forms of copper metabolism, the underlying genetic defects remain elusive. Several pure bred dog populations are affected with copper-associated hepatitis showing similarities to human copper metabolism disorders. Gene-mapping studies in these populations offer the opportunity to discover new genes involved in copper metabolism. Furthermore, due to the relatively large body size and long life-span of dogs they are excellent models for development of new treatment strategies. One example is the recent use of canine organoids for disease modeling and gene therapy of copper storage disease. This review addresses the opportunities offered by canine genetics for discovery of genes involved in copper metabolism disorders. Further, possibilities for the use of dogs in development of new treatment modalities for copper storage disorders, including gene repair in patient-derived hepatic organoids, are highlighted.

  2. Choking Prevention

    Science.gov (United States)

    ... Healthy Living Healthy Living Healthy Living Nutrition Fitness Sports Oral Health Emotional Wellness Growing Healthy Sleep Safety & Prevention Safety & Prevention Safety and Prevention Immunizations At Home ...

  3. Thermal conductivity of glass copper-composite

    International Nuclear Information System (INIS)

    Kinoshita, Makoto; Terai, Ryohei; Haidai, Haruki

    1980-01-01

    Glass-metal composites are to be one of the answers for promoting thermal conduction in the glassy solids containing high-level radioactive wastes. In order to investigate the effect of metal addition on thermal conductivity of glasses, glass-copper composites were selected, and the conductivities of the composites were measured and discussed in regards to copper content and microstructure. Fully densified composites were successfully prepared by pressure sintering of the powder mixtures of glass and copper at temperatures above the yield points of the constituent glasses if the copper content was not so much. The conductivity was measured by means of a comparative method, in which the thermal gradient of the specimen was compared with that of quartz glass as standard under thermally steady state. Measurements were carried out at around 50 0 C. The thermal conductivity increased with increasing content of copper depending on the kind of copper powder used. The conductivities of the composites of the same copper content differed considerably each another. Fine copper powder was effective on increasing conductivity, and the conductivity became about threefold of that of glass by mixing the fine copper powder about 10 vol%. For the composites containing the fine copper powder less than 5 vol%, the conductivity obeyed so-called logarithmic rule, one of the mixture rules of conductivity, whereas for composites containing more than 5 vol%, the conductivity remarkably increased apart from the rule. This fact suggests that copper becomes continuous in the composite when the copper content increased beyond 5 vol%. For the composites containing coarse copper powder, the conductivity was increased not significantly, and obeyed an equation derived from the model in which conductive material dispersed in less conductive one. (author)

  4. Eutectic structures in friction spot welding joint of aluminum alloy to copper

    Science.gov (United States)

    Shen, Junjun; Suhuddin, Uceu F. H.; Cardillo, Maria E. B.; dos Santos, Jorge F.

    2014-05-01

    A dissimilar joint of AA5083 Al alloy and copper was produced by friction spot welding. The Al-MgCuAl2 eutectic in both coupled and divorced manners were found in the weld. At a relatively high temperature, mass transport of Cu due to plastic deformation, material flow, and atomic diffusion, combined with the alloy system of AA5083 are responsible for the ternary eutectic melting.

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

    CERN Document Server

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

    2011-01-01

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

  6. Carbon mediated reduction of silicon dioxide and growth of copper silicide particles in uniform width channels

    DEFF Research Database (Denmark)

    Pizzocchero, Filippo; Bøggild, Peter; Booth, Tim

    2013-01-01

    We show that surface arc-discharge deposited carbon plays a critical intermediary role in the breakdown of thermally grown oxide diffusion barriers of 90 nm on a silicon wafer at 1035°C in an Ar/H2 atmosphere, resulting in the formation of epitaxial copper silicide particles in ≈ 10 μm wide...... electron microscopy of focused ion beam fabricated lammelas and trenches in the structure to elucidate the process of their formation....

  7. Eutectic structures in friction spot welding joint of aluminum alloy to copper

    International Nuclear Information System (INIS)

    Shen, Junjun; Suhuddin, Uceu F. H.; Cardillo, Maria E. B.; Santos, Jorge F. dos

    2014-01-01

    A dissimilar joint of AA5083 Al alloy and copper was produced by friction spot welding. The Al-MgCuAl 2 eutectic in both coupled and divorced manners were found in the weld. At a relatively high temperature, mass transport of Cu due to plastic deformation, material flow, and atomic diffusion, combined with the alloy system of AA5083 are responsible for the ternary eutectic melting

  8. Diffuse interstellar clouds

    International Nuclear Information System (INIS)

    Black, J.H.

    1987-01-01

    The author defines and discusses the nature of diffuse interstellar clouds. He discusses how they contribute to the general extinction of starlight. The atomic and molecular species that have been identified in the ultraviolet, visible, and near infrared regions of the spectrum of a diffuse cloud are presented. The author illustrates some of the practical considerations that affect absorption line observations of interstellar atoms and molecules. Various aspects of the theoretical description of diffuse clouds required for a full interpretation of the observations are discussed

  9. Self diffusion in tungsten

    International Nuclear Information System (INIS)

    Mundy, J.N.; Rothman, S.J.; Lam, N.Q.; Nowicki, L.J.; Hoff, H.A.

    1978-01-01

    The lack of understanding of self-diffusion in Group VI metals together with the wide scatter in the measured values of tungsten self-diffusion has prompted the present measurements to be made over a wide temperature range (1/2Tsub(m) to Tsub(m)). The diffusion coefficients have been measured in the temperature range 1430-2630 0 C. The present measurements show non-linear Arrhenius behavior but a reliable two-exponential fit of the data should await further measurements. (Auth.)

  10. Diffuse Ceiling Ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen; Yu, Tao; Heiselberg, Per Kvols

    -cooling period and night cooling potential. The investment cost of this ventilation system is about 5-10% lower than the conventional ones, because the acoustic ceiling could be directly applied as air diffuser and the use of plenum to distribute air reduces the cost of ductwork. There is a growing interest...... in applying diffuse ceiling ventilation in offices and other commercial buildings because of the benefits from both thermal comfort and energy efficiency aspects. The design guide introduces the principle and key characteristics of room air distribution with diffuse ceiling ventilation and the design...

  11. Diffuse Ceiling Ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen; Yu, Tao; Heiselberg, Per Kvols

    -cooling period and night cooling potential. The investment cost of this ventilation system is about 5-10% lower than the conventional ones, because the acoustic ceiling could be directly applied as air diffuser and the use of plenum to distribute air reduces the cost of ductwork. There is a growing interest...... and manufacturers and the users of diffuse ceiling technology. The design guide introduces the principle and key characteristics of room air distribution with diffuse ceiling ventilation. It provides an overview of potential benefit and limitations of this technology. The benefits include high thermal comfort, high...

  12. Evaluation of copper resistant bacteria from vineyard soils and mining waste for copper biosorption.

    Science.gov (United States)

    Andreazza, R; Pieniz, S; Okeke, B C; Camargo, F A O

    2011-01-01

    Vineyard soils are frequently polluted with high concentrations of copper due application of copper sulfate in order to control fungal diseases. Bioremediation is an efficient process for the treatment of contaminated sites. Efficient copper sorption bacteria can be used for bioremoval of copper from contaminated sites. In this study, a total of 106 copper resistant bacteria were examined for resistance to copper toxicity and biosorption of copper. Eighty isolates (45 from vineyard Mollisol, 35 from Inceptisol) were obtained from EMBRAPA (Empresa Brasileira de Pesquisa Agropecuária) experimental station, Bento Gonçalves, RS, Brazil (29°09'53.92″S and 51°31'39.40″W) and 26 were obtained from copper mining waste from Caçapava do Sul, RS, Brazil (30°29'43.48″S and 53'32'37.87W). Based on resistance to copper toxicity and biosorption, 15 isolates were identified by 16S rRNA gene sequencing. Maximal copper resistance and biosorption at high copper concentration were observed with isolate N2 which removed 80 mg L(-1) in 24 h. Contrarily isolate N11 (Bacillus pumilus) displayed the highest specific copper biosorption (121.82 mg/L/OD unit in 24 h). GenBank MEGABLAST analysis revealed that isolate N2 is 99% similar to Staphylococcus pasteuri. Results indicate that several of our isolates have potential use for bioremediation treatment of vineyards soils and mining waste contaminated with high copper concentration.

  13. Low-cost optical fabrication of flexible copper electrode via laser-induced reductive sintering and adhesive transfer

    Science.gov (United States)

    Back, Seunghyun; Kang, Bongchul

    2018-02-01

    Fabricating copper electrodes on heat-sensitive polymer films in air is highly challenging owing to the need of expensive copper nanoparticles, rapid oxidation of precursor during sintering, and limitation of sintering temperature to prevent the thermal damage of the polymer film. A laser-induced hybrid process of reductive sintering and adhesive transfer is demonstrated to cost-effectively fabricate copper electrode on a polyethylene film with a thermal resistance below 100 °C. A laser-induced reductive sintering process directly fabricates a high-conductive copper electrode onto a glass donor from copper oxide nanoparticle solution via photo-thermochemical reduction and agglomeration of copper oxide nanoparticles. The sintered copper patterns were transferred in parallel to a heat-sensitive polyethylene film through self-selective surface adhesion of the film, which was generated by the selective laser absorption of the copper pattern. The method reported here could become one of the most important manufacturing technologies for fabricating low-cost wearable and disposable electronics.

  14. Theories on diffusion of technology

    DEFF Research Database (Denmark)

    Munch, Birgitte

    Tracing the body of the diffusion proces by analysing the diffusion process from historical, sociological, economic and technical approaches. Discussing central characteristics of the proces of diffusion og CAD/CAM in Denmark....

  15. LEP Radio Frequency Copper Cavity

    CERN Multimedia

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  16. Copper-Carbon Nanoforms Composites – Processing, Microstructure and Thermal Properties

    Directory of Open Access Journals (Sweden)

    Pietrzak K.

    2017-06-01

    Full Text Available The main current of publication is focused around the issues and problems associated with the formation of composite materials with Cu matrix and reinforcing phases in the various carbon nanoforms. The core of the research has been focused on thermal conductivity of these composites types. This parameter globally reflects the state of the structure, quality of raw materials and the technology used during the formation of composite materials. Vanishingly low affinity of copper for carbon, multilayered forms of graphene, the existence of critical values of graphene volume in the composite are not conducive to the classic procedures of composites designing. As a result, the expected, significant increase in thermal conductivity of composites is not greater than for pure copper matrix. Present paper especially includes: (i data of obtaining procedure of copper/graphene mixtures, (ii data of sintering process, (iii the results of structure investigations and of thermal properties. Structural analysis revealed the homogenous distribution of graphene in copper matrix, the thermal analysis indicate the existence of carbon phase critical concentration, where improvement of thermal diffusivity to pure copper can occur.

  17. Lead and copper removal from aqueous solutions using carbon foam derived from phenol resin.

    Science.gov (United States)

    Lee, Chang-Gu; Jeon, Jun-Woo; Hwang, Min-Jin; Ahn, Kyu-Hong; Park, Chanhyuk; Choi, Jae-Woo; Lee, Sang-Hyup

    2015-07-01

    Phenolic resin-based carbon foam was prepared as an adsorbent for removing heavy metals from aqueous solutions. The surface of the produced carbon foam had a well-developed open cell structure and the specific surface area according to the BET model was 458.59m(2)g(-1). Batch experiments showed that removal ratio increased in the order of copper (19.83%), zinc (34.35%), cadmium (59.82%), and lead (73.99%) in mixed solutions with the same initial concentration (50mgL(-1)). The results indicated that the Sips isotherm model was the most suitable for describing the experimental data of lead and copper. The maximum adsorption capacity of lead and copper determined to Sips model were 491mgg(-1) and 247mgg(-1). The obtained pore diffusion coefficients for lead and copper were found to be 1.02×10(-6) and 2.42×10(-7)m(2)s(-1), respectively. Post-sorption characteristics indicated that surface precipitation was the primary mechanism of lead and copper removal by the carbon foam, while the functional groups on the surface of the foam did not affect metal adsorption. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. The anodization synthesis of copper oxide nanosheet arrays and their photoelectrochemical properties

    Science.gov (United States)

    Shu, Xia; Zheng, Hongmei; Xu, Guangqing; Zhao, Jiebo; Cui, Lihua; Cui, Jiewu; Qin, Yongqiang; Wang, Yan; Zhang, Yong; Wu, Yucheng

    2017-08-01

    We studied the growth of copper oxide nanosheet arrays on copper foil via a simple anodization method. The structures, morphologies, and elemental compositions of the specimens were characterized with an X-ray diffractometer, scanning electron microscope, high resolution transmission electron microscope, and X-ray photoelectron spectrometer. The copper oxide (Cu2O and CuO) nanosheet arrays were comprised of 30-nm-thick nanosheets that stand vertically on the Cu substrate. The anodizing parameters, such as the current density, temperature, and polyethylene glycol concentration, were optimized to obtain the regular nanosheet arrays. The optical absorption properties of the anodized products were evaluated using a diffuse reflectance spectrometer, and broad and strong optical absorption bands arising from the UV to visible region were observed. The photoelectrochemical performance of the nanosheet arrays was measured with chronoamperometry and cyclic voltammetry on an electrochemical workstation equipped with a Xe lamp (wavelength >400 nm). A negative photocurrent was obtained due to the p-type semiconductor of the copper oxides. The copper oxide nanosheet arrays achieve the highest photocurrent of 0.4 mA/cm2 at the current density of 1.0 A/dm2, temperature of 70 °C, and polyethylene glycol concentration of 0.5 g/L.

  19. Tensile and electrical properties of high-strength high-conductivity copper alloys

    International Nuclear Information System (INIS)

    Zinkle, S.J.; Eatherly, W.S.

    1998-01-01

    Electrical conductivity and tensile properties have been measured on an extruded and annealed CuCrNb dispersion strengthened copper alloy which has been developed for demanding aerospace high heat flux applications. The properties of this alloy are somewhat inferior to GlidCop dispersion strengthened copper and prime-aged CuCrZr over the temperature range of 20--500 C. However, if the property degradation in CuCrZr due to joining operations and the anisotropic properties of GlidCop in the short transverse direction are taken into consideration, CuCrNb may be a suitable alternative material for high heat flux structural applications in fusion energy devices. The electrical conductivity and tensile properties of CuCrZr that was solution annealed and then simultaneously aged and diffusion bonded are also summarized. A severe reduction in tensile elongation is observed in the diffusion bonded joint, particularly if a thin copper shim is not placed in the diffusion bondline

  20. Diffusion of Wilson loops

    International Nuclear Information System (INIS)

    Brzoska, A.M.; Lenz, F.; Thies, M.; Negele, J.W.

    2005-01-01

    A phenomenological analysis of the distribution of Wilson loops in SU(2) Yang-Mills theory is presented in which Wilson loop distributions are described as the result of a diffusion process on the group manifold. It is shown that, in the absence of forces, diffusion implies Casimir scaling and, conversely, exact Casimir scaling implies free diffusion. Screening processes occur if diffusion takes place in a potential. The crucial distinction between screening of fundamental and adjoint loops is formulated as a symmetry property related to the center symmetry of the underlying gauge theory. The results are expressed in terms of an effective Wilson loop action and compared with various limits of SU(2) Yang-Mills theory

  1. On Diffusion and Permeation

    KAUST Repository

    Peppin, Stephen S. L.

    2009-01-01

    Diffusion and permeation are discussed within the context of irreversible thermodynamics. A new expression for the generalized Stokes-Einstein equation is obtained which links the permeability to the diffusivity of a two-component solution and contains the poroelastic Biot-Willis coefficient. The theory is illustrated by predicting the concentration and pressure profiles during the filtration of a protein solution. At low concentrations the proteins diffuse independently while at higher concentrations they form a nearly rigid porous glass through which the fluid permeates. The theoretically determined pressure drop is nonlinear in the diffusion regime and linear in the permeation regime, in quantitative agreement with experimental measurements. © 2009 Walter de Gruyter, Berlin, New York.

  2. Computational Diffusion MRI

    CERN Document Server

    Grussu, Francesco; Ning, Lipeng; Tax, Chantal; Veraart, Jelle

    2018-01-01

    This volume presents the latest developments in the highly active and rapidly growing field of diffusion MRI. The reader will find numerous contributions covering a broad range of topics, from the mathematical foundations of the diffusion process and signal generation, to new computational methods and estimation techniques for the in-vivo recovery of microstructural and connectivity features, as well as frontline applications in neuroscience research and clinical practice. These proceedings contain the papers presented at the 2017 MICCAI Workshop on Computational Diffusion MRI (CDMRI’17) held in Québec, Canada on September 10, 2017, sharing new perspectives on the most recent research challenges for those currently working in the field, but also offering a valuable starting point for anyone interested in learning computational techniques in diffusion MRI. This book includes rigorous mathematical derivations, a large number of rich, full-colour visualisations and clinically relevant results. As such, it wil...

  3. Isomorphism, Diffusion and Decoupling

    DEFF Research Database (Denmark)

    Boxenbaum, Eva; Jonsson, Stefan

    2017-01-01

    This chapter traces the evolution of the core theoretical constructs of isomorphism, decoupling and diffusion in organizational institutionalism. We first review the original theoretical formulations of these constructs and then examine their evolution in empirical research conducted over the past...

  4. Resilient Diffusive Clouds

    Science.gov (United States)

    2017-02-01

    RESILIENT DIFFUSIVE CLOUDS TRUSTEES OF DARTMOUTH COLLEGE FEBRUARY 2017 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC...To) SEP 2011 – SEP 2016 4. TITLE AND SUBTITLE RESILIENT DIFFUSIVE CLOUDS 5a. CONTRACT NUMBER FA8750-11-2-0257 5b. GRANT NUMBER N/A 5c. PROGRAM...diversified virtual machines. The concepts lead to a view of cloud computing in which vulnerabilities are different at every host, attackers cannot

  5. Evaluation of synthesized iron oxide nanoparticles in removal of copper ions from aqueous solution

    Directory of Open Access Journals (Sweden)

    MH Salmani

    2016-11-01

    Full Text Available Abstract Introduction: water source pollutant, result of direct releasing of metal ions to environment, is one of the most important problems in the world. In this study, efficiency of synthesized iron oxide nanoparticles in presence of extract tangerine Peel was investigated for removal of copper ions in the solution. Methods: Iron oxide nanoparticles were prepared by co-perception method using Tangerine Peel extract. The Tangerine Peel extract used to decrease of nanoparticle size and to prevent of particles coagulation. The effect of different parameter includes initial copper concentration, adsorbent dose, contact time and solution pH was investigated on removal of copper. The experimental data were fitted to Langmuir and Freundlich isotherm models. Results: The results showed that the removal efficiency was increased by increasing of pH and decreased from 88% to 81% by increasing of initial copper concentration from 5 mg/l to 10 mg/l. The most removal percent was 92% when copper concentration was 5 mg/l and adsorbent doze was 0.6 g in 100 ml suspension. Conclusion: The results showed the removal efficiency is depended on to pH. The increase of copper concentration decreased the removal efficiency. Adsorption experimental data were in good accordance with Langmuir isotherm model. The synthesized iron oxide nanoparticles with extract Tangerine Peel is a good adsorbent for removing of heavy metals from aqueous solution.

  6. Biocidal efficacy of copper alloys against pathogenic enterococci involves degradation of genomic and plasmid DNAs.

    Science.gov (United States)

    Warnes, S L; Green, S M; Michels, H T; Keevil, C W

    2010-08-01

    The increasing incidence of nosocomial infections caused by glycopeptide-resistant enterococci is a global concern. Enterococcal species are also difficult to eradicate with existing cleaning regimens; they can survive for long periods on surfaces, thus contributing to cases of reinfection and spread of antibiotic-resistant strains. We have investigated the potential use of copper alloys as bactericidal surfaces. Clinical isolates of vancomycin-resistant Enterococcus faecalis and Enterococcus faecium were inoculated onto copper alloy and stainless steel surfaces. Samples were assessed for the presence of viable cells by conventional culture, detection of actively respiring cells, and assessment of cell membrane integrity. Both species survived for up to several weeks on stainless steel. However, no viable cells were detected on any alloys following exposure for 1 h at an inoculum concentration of copper surfaces that is not evident in cells recovered from stainless steel. The DNA fragmentation is so extensive, and coupled with the rapid cell death which occurs on copper surfaces, that it suggests that mutation is less likely to occur. It is therefore highly unlikely that genetic information can be transferred to receptive organisms recontaminating the same area. A combination of effective cleaning regimens and contact surfaces containing copper could be useful not only to prevent the spread of viable pathogenic enterococci but also to mitigate against the occurrence of potential resistance to copper, biocides, or antibiotics and the spread of genetic determinants of resistance to other species.

  7. Copper Dependence of Angioproliferation in Pulmonary Arterial Hypertension in Rats and Humans

    Science.gov (United States)

    Mizuno, Shiro; Guignabert, Christophe; Al Hussaini, Aysar A.; Farkas, Daniela; Ruiter, Gerrina; Kraskauskas, Donatas; Fadel, Elie; Allegood, Jeremy C.; Humbert, Marc; Noordegraaf, Anton Vonk; Spiegel, Sarah; Farkas, Laszlo; Voelkel, Norbert F.

    2012-01-01

    Obliteration of the vascular lumen by endothelial cell growth is a hallmark of many forms of severe pulmonary arterial hypertension. Copper plays a significant role in the control of endothelial cell proliferation in cancer and wound-healing. We sought to determine whether angioproliferation in rats with experimental pulmonary arterial hypertension and pulmonary microvascular endothelial cell proliferation in humans depend on the proangiogenic action of copper. A copper-depleted diet prevented, and copper chelation with tetrathiomolybdate reversed, the development of severe experimental pulmonary arterial hypertension. The copper chelation–induced reopening of obliterated vessels was caused by caspase-independent apoptosis, reduced vessel wall cell proliferation, and a normalization of vessel wall structure. No evidence was found for a role of super oxide–1 inhibition or lysyl–oxidase–1 inhibition in the reversal of angioproliferation. Tetrathiomolybdate inhibited the proliferation of human pulmonary microvascular endothelial cells, isolated from explanted lungs from control subjects and patients with pulmonary arterial hypertension. These data suggest that the inhibition of endothelial cell proliferation by a copper-restricting strategy could be explored as a new therapeutic approach in pulmonary arterial hypertension. It remains to be determined, however, whether potential toxicity to the right ventricle is offset by the beneficial pulmonary vascular effects of antiangiogenic treatment in patients with pulmonary arterial hypertension. PMID:22162909

  8. Synthesis of Functionalized Aliphatic Polyesters by the ``Click'' Copper-Catalyzed Alkyne—Azide Cycloaddition

    Science.gov (United States)

    Lecomte, Philippe; Riva, Raphael; Jerome, Christine

    The functionalization of aliphatic polyesters by the copper-mediated azide—alkyne Huisgen's cycloaddition is very efficient under mild conditions, which prevents degradation from occurring. The implementation of this reaction requires the synthesis of aliphatic polyesters bearing pendant alkynes and azides, which can be carried out either by polycondensation or by ring-opening polymerization.

  9. Advanced manufacturing: Technology diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Tesar, A.

    1995-12-01

    In this paper we examine how manufacturing technology diffuses rom the developers of technology across national borders to those who do not have the capability or resources to develop advanced technology on their own. None of the wide variety of technology diffusion mechanisms discussed in this paper are new, yet the opportunities to apply these mechanisms are growing. A dramatic increase in technology diffusion occurred over the last decade. The two major trends which probably drive this increase are a worldwide inclination towards ``freer`` markets and diminishing isolation. Technology is most rapidly diffusing from the US In fact, the US is supplying technology for the rest of the world. The value of the technology supplied by the US more than doubled from 1985 to 1992 (see the Introduction for details). History shows us that technology diffusion is inevitable. It is the rates at which technologies diffuse to other countries which can vary considerably. Manufacturers in these countries are increasingly able to absorb technology. Their manufacturing efficiency is expected to progress as technology becomes increasingly available and utilized.

  10. Functional understanding of the versatile protein copper metabolism MURR1 domain 1 (COMMD1) in copper homeostasis

    NARCIS (Netherlands)

    Fedoseienko, Alina; Bartuzi, Paulina; van de Sluis, Bart

    2014-01-01

    Copper is an important cofactor in numerous biological processes in all living organisms. However, excessive copper can be extremely toxic, so it is vital that the copper level within a cell is tightly regulated. The damaging effect of copper is seen in several hereditary forms of copper toxicity in

  11. Electronics scrap processing at Brixlegg copper works

    Energy Technology Data Exchange (ETDEWEB)

    Kaltenboeck, F.J.; Sauer, E.; Woebking, H.; Woerz, H.

    1985-11-01

    The valuable metals - in particular precious metals, copper, zinc, and tin - that are included in electronics scraps are recovered in the secondary copper works of Brixlegg in the form of commercial intermediate products or in the form of pure metals. The refinery line is as follows: shaft furnace, converter, anode furnace, electrolytic copper refinery and slime plants for precious metal recovery from anode slimes. (orig.).

  12. Alteration of uraniferous and native copper concretions in the Permian mudrocks of south Devon, United Kingdom

    Energy Technology Data Exchange (ETDEWEB)

    Milodowski, A.E.; Styles, M.T.; Horstwood, M.S.A.; Kemp, S.J. [British Geological Survey, Nottingham (United Kingdom)

    2002-03-01

    very variable, both from one sample to another and from one point on a sample to another. This study largely confirms the observations reported in the pilot study. The alteration of the copper is dominated by copper oxides. This the earliest alteration product observed and comprises principally cuprite (Cu{sub 2}O), with probable minor tenorite (CuO). The cuprite typically forms colloform layers on the copper surface, and localised lobate embayments or corrosion pits that 'eat' more deeply into the copper metal. Microchemical observations reveal evidence for the enrichment of copper in the mudstone matrix immediately adjacent to the altered copper sheets. The copper concentration drops from around 100% in the cuprite rims of the sheets down to around 1 wt % over a distance of about 20 gm from the altered sheets. With increasing distances away from the sheets there is a more gradual decrease in copper concentration over distances of 100-200 {mu}m to the local background level of the host rock - which may be as high as 2-3 wt % in some places but is generally of the order of 0. 1 wt % Cu{sub 2}0. The high copper concentration could be due to redistribution of copper from the corroded sheets. Alternatively, it could represent a diffusive 'halo' of copper enhancement around the original mineralised structure (bedding laminae or fracture) that formed at the same time as the copper sheets. In both cases, the observations indicate that diffusion occurred over distances of only a few hundreds of micro metres in the mudstone or siltstone matrix. The uraniferous 'fish-eye' concretions contain high concentration of uranium within their cores. Most of the uranium is concentrated in the outer edges of the dark vanadium-rich core of the concretion and subsequent concentric bands of vanadium enriched diffusion bands, and associated fin-like structures. Here, it is present largely as uranium silicate and subordinate uraninite (pitchblende), closely

  13. Alteration of uraniferous and native copper concretions in the Permian mudrocks of south Devon, United Kingdom

    International Nuclear Information System (INIS)

    Milodowski, A.E.; Styles, M.T.; Horstwood, M.S.A.; Kemp, S.J.

    2002-03-01

    very variable, both from one sample to another and from one point on a sample to another. This study largely confirms the observations reported in the pilot study. The alteration of the copper is dominated by copper oxides. This the earliest alteration product observed and comprises principally cuprite (Cu 2 O), with probable minor tenorite (CuO). The cuprite typically forms colloform layers on the copper surface, and localised lobate embayments or corrosion pits that 'eat' more deeply into the copper metal. Microchemical observations reveal evidence for the enrichment of copper in the mudstone matrix immediately adjacent to the altered copper sheets. The copper concentration drops from around 100% in the cuprite rims of the sheets down to around 1 wt % over a distance of about 20 gm from the altered sheets. With increasing distances away from the sheets there is a more gradual decrease in copper concentration over distances of 100-200 μm to the local background level of the host rock - which may be as high as 2-3 wt % in some places but is generally of the order of 0. 1 wt % Cu 2 0. The high copper concentration could be due to redistribution of copper from the corroded sheets. Alternatively, it could represent a diffusive 'halo' of copper enhancement around the original mineralised structure (bedding laminae or fracture) that formed at the same time as the copper sheets. In both cases, the observations indicate that diffusion occurred over distances of only a few hundreds of micro metres in the mudstone or siltstone matrix. The uraniferous 'fish-eye' concretions contain high concentration of uranium within their cores. Most of the uranium is concentrated in the outer edges of the dark vanadium-rich core of the concretion and subsequent concentric bands of vanadium enriched diffusion bands, and associated fin-like structures. Here, it is present largely as uranium silicate and subordinate uraninite (pitchblende), closely associated with copper, nickel and cobalt

  14. Microstructural and component evolution of self-assembled nanoperiod multilayered carbon-copper films with deposition pressure

    Directory of Open Access Journals (Sweden)

    Weiqi Wang

    2017-04-01

    Full Text Available Here, we report a facile synthesis method for the fabrication of various nanoperiod multilayers in carbon-copper films only by conveniently changing the deposition pressure from the reactive magnetron sputter process. To obtain the nano-multilayered structure with different number of layers, only one single sputtering target of copper is used at gas pressure varied from 0.4 Pa to 1.2 Pa by flowing gas mixture of argon and methane, while 600W DC input power is applied to a copper target. The influence of deposition pressure on the microstructure and constitution of the films are investigated by X-ray photoelectron spectroscopy (XPS, field emission scanning electron microscopy (FESEM and high-resolution transmission electron microscopy (HRTEM. The results show that carbon-rich layers and copper-rich layers are alternately arranged to self-organize the multilayered structure in the carbon-copper films, both of the carbon-rich layer and copper-rich layer constitute a period. The amount of layers in the multilayered structure is found to decrease with the deposition pressure, the film deposited with 0.4 Pa has the maximum layers and the highest copper content compared with the other deposition pressure. Effects of the growth condition on the growth rate, the number of the layers and the energy of plasmas during deposition process are discussed. Based on the (a influence of the effect of carbon absorbed on the copper target leading to target poisoning, (b influence of deposition pressure on the energy of etching ions and (c the energetic ions bombardment enhanced inter diffusion of deposition ions, the mechanism of self-organized formation of nano-multilayer in the carbon-copper films with various number of layer is proposed.

  15. Microstructure effects in CVD copper

    Science.gov (United States)

    Manger, Dirk Karl

    Computer chip manufacturers are beginning to implement copper as interconnect material in high-performance microprocessor metallization architectures. Replacing currently used aluminum metallization with its copper based counterpart will result in performance gain due to the low resistivity of copper (1.67muO·cm) which generates a reduction in (resistance x capacitance) signal delay. Futhermore, enhancements in stress and electromigration resistance by up to three orders of magnitude are expected from replacing aluminum with copper. Copper deposited by chemical vapor deposition has the proven ability to yield complete fill of aggressive via and trench structures at high deposition rates. At the same time, ultrathin Cu seed layers can be controlled grown by chemical vapor deposition (CVD) for use as activation layer in electrolytic plating (EP) applications. Additionally, integration studies using single and two-level damascene interconnect structures CVD Cu showed that excellent yield can be obtained. However, before CVD Cu can be incorporated into manufacturing process flows, several key reliability issues have to be addressed and resolved. At present, electroplating has the advantage of enhanced electromigration performance compared to CVD copper. It is therefore necessary to demonstrate the systematic ability to tailor the microstructure of CVD copper with the goal of enhanced electromigration and stress migration performance through the successful formation of (111) textured Cu with bamboo type microstructure. In the present work, the evolution of as-deposited Cu resistivity, grain size, texture, and surface roughness were systematically analyzed as a function of film thickness for an optimized CVD Cu process. In particular, investigations of the influence of substrate type and surface pretreatment on texture and grain size showed that: (a) Cu grows (111) textured on PVD TiN, if (002) Ti matrix is present, and on inorganic CVD TiN, regardless of the underlying

  16. Prevention and control of apple scab

    NARCIS (Netherlands)

    Heijne, B.; Jong, de P.F.; Köhl, J.; Speksnijder, A.G.C.L.; Hockenhull, J.; Bengtsson, M.; Lindhard Pederson, H.; Paaske, K.; Eiben, U.; Tamm, L.; Trapman, M.

    2006-01-01

    Improved prevention and control of apple scab caused by Venturia inaequalis is aimed at without the use of copper containing products in the Repco-project. Substantial progress is made in selection of potential products against summer epidemics. A patent application is made for E73. New effective

  17. Copper welding; Les liaisons du cuivre

    Energy Technology Data Exchange (ETDEWEB)

    Monneau, Ph. [SDMS, 38 - Saint-Romans (France)

    2000-07-01

    The following categories of manufactured copper: Cu-c ( > 99.95% copper and less than 0.0003% phosphor) and Cu-OF (oxygen free copper) are useful in vacuum or ultra-vacuum techniques. Homogeneous binding (or heterogeneous with other metals) are mainly performed by welding (TIG, MIG, FE) or by brazing at high or low temperatures. In this article these different methods are reviewed with pros and cons, and several applications are presented, particularly the designing of high frequency resonator cavities for GANIL accelerator, these cavities were made out of solid copper. (A.C.)

  18. Assessment of the anti-biofouling potentials of a copper iodide-doped nylon mesh.

    Science.gov (United States)

    Sato, Tetsuya; Fujimori, Yoshie; Nakayama, Tsuruo; Gotoh, Yasuo; Sunaga, Yoshihiko; Nemoto, Michiko; Matsunaga, Tadashi; Tanaka, Tsuyoshi

    2012-08-01

    We propose a copper iodide (CuI)-doped nylon mesh prepared using polyiodide ions as a precursor toward anti-biofouling polymer textile. The CuI-doped nylon mesh was subjected to the prevention of biofouling in marine environments. The attachment of the marine organisms was markedly inhibited on the CuI-doped nylon mesh surface until 249 days. Scanning electron microscopy-energy dispersive X-ray analysis indicated that copper compounds were maintained in the nylon mesh after the field experiment, although copper content in the nylon mesh was reduced. Therefore, the copper ions slowly dissolved from nylon mesh will contribute to the long-term prevention of biofouling. Furthermore, electron spin resonance analysis revealed the generation of reactive oxygen species (ROS) from CuI-doped nylon mesh after the field experiment. One of the possibilities for toxic action of copper ions will be the direct effect of Cu+ -induced ROS on biofilm forming on nylon mesh surface. The proposed polymer textile can be applied to fishing and aquafarming nets, mooring rope for ship, or silt fence to restrict polluted water in marine environments.

  19. Adsorption behavior of caffeine as a green corrosion inhibitor for copper

    International Nuclear Information System (INIS)

    Souza, Fernando Sílvio de; Giacomelli, Cristiano; Gonçalves, Reinaldo Simões; Spinelli, Almir

    2012-01-01

    Electrochemical and impedance experiments were carried out to evaluate the corrosion behavior of copper in aerated 0.1 mol L −1 H 2 SO 4 solutions in the presence of three xanthine derivatives with similar chemical structures. The corrosion rate of copper was found to increase in the presence of theophylline and theobromine and decrease in the presence of caffeine. The adsorption and inhibitory effect of caffeine on copper surfaces in aerated 0.1 mol L −1 H 2 SO 4 solutions were then investigated in detail by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), contact angle measurements, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and fluorescence experiments. The data obtained indicate that caffeine behaves as a cathodic-type inhibitor adsorbing onto the copper surface according to the Temkin isotherm, with the negative ∆G° ads value of − 31.1 kJ mol −1 signifying a spontaneous adsorption process. The corrosion inhibition efficiency increased with caffeine concentration in the range of 1.0–10.0 mmol L −1 . Furthermore, the EIS results obtained at the open-circuit potential and surface analysis (SEM, EDS and fluorescence) clearly demonstrated the adsorption of the organic compound onto the copper electrode. The contact angle measurements revealed the formation of a hydrophobic protective film. This film covers up to 72% of the total active surface, acts as a protective barrier and prevents interaction between the metal, water and oxygen molecules. - Highlights: ► We have investigated the adsorption and corrosion inhibition of caffeine on copper surfaces. ► Caffeine behaves as a cathodic-type inhibitor. ► Caffeine adsorbs onto copper surface according to Temkin isotherm. ► There exists the formation of a hydrophobic film that acts as a protective barrier. ► This corrosion inhibitor covers up to 72% of the total active surface of copper.

  20. Copper-silver ionization at a US hospital: interaction of treated ...

    Science.gov (United States)

    Tap water sampling and surface analysis of copper pipe/bathroom porcelain were performed to explore the fate of copper and silver during the first nine months of copper-silver ionization (CSI) applied to cold and hot water at a hospital in Cincinnati, Ohio. Ions dosed by CSI into the water at its point of entry to the hospital were inadvertently removed from hot water by a cation-exchange softener in one building (average removal of 72% copper and 51% silver). Copper at the tap was replenished from corrosion of the building’s copper pipes but was typically unable to reach 200 µg/L in first-draw and flushed hot and cold water samples. Unlike copper, silver solubility was not restricted by the incoming water’s high pH of 8.5. Cold water lines had >20 µg/L silver at most of the taps that were sampled, which further increased after flushing. However, silver plating onto copper pipe surfaces (particularly in the hot water line) prevented reaching 20 µg/L silver in hot water of many taps. Aesthetically displeasing purple/grey stains in bathroom porcelain were attributed to chlorargyrite [AgCl(s)], an insoluble precipitate that formed when CSI-dosed Ag+ ions combined with Cl- ions that were present in the incoming water. Overall, CSI aims to control Legionella bacteria in drinking water, but plumbing material interactions, aesthetics and other implications also deserve consideration to holistically evaluate in-building drinking water disinfection. To inform the

  1. The copper-transporting ATPase pump and its potential role in copper-tolerance

    Science.gov (United States)

    Katie Ohno; C.A. Clausen; Frederick Green; G. Stanosz

    2016-01-01

    Copper-tolerant brown-rot decay fungi exploit intricate mechanisms to neutralize the efficacy of copper-containing preservative formulations. The production and accumulation oxalate is the most widely recognized theory regarding the mechanism of copper-tolerance in these fungi. The role of oxalate, however, may be only one part of a series of necessary components...

  2. Disposable copper-based electrochemical sensor for anodic stripping voltammetry.

    Science.gov (United States)

    Pei, Xing; Kang, Wenjing; Yue, Wei; Bange, Adam; Heineman, William R; Papautsky, Ian

    2014-05-20

    In this work, we report the first copper-based point-of-care sensor for electrochemical measurements demonstrated by zinc determination in blood serum. Heavy metals require careful monitoring, yet current methods are too complex for a point-of-care system. Electrochemistry offers a simple approach to metal detection on the microscale, but traditional carbon, gold (Au), or platinum (Pt) electrodes are difficult or expensive to microfabricate, preventing widespread use. Our sensor features a new low-cost electrode material, copper, which offers simple fabrication and compatibility with microfabrication and PCB processing, while maintaining competitive performance in electrochemical detection. Anodic stripping voltammetry of zinc using our new copper-based sensors exhibited a 140 nM (9.0 ppb) limit of detection (calculated) and sensitivity greater than 1 μA/μM in the acetate buffer. The sensor was also able to determine zinc in a bovine serum extract, and the results were verified with independent sensor measurements. These results demonstrate the advantageous qualities of this lab-on-a-chip electrochemical sensor for clinical applications, which include a small sample volume (μL scale), reduced cost, short response time, and high accuracy at low concentrations of analyte.

  3. Electron beam hardening type copper plate printing ink

    International Nuclear Information System (INIS)

    Kawamura, Eiji; Inoue, Mitsuo; Kusaki, Satoichiro

    1989-01-01

    Copper plate printing is the printing method of filling ink in the parts of concave printing elements on a type area, and transferring the ink to a base, and it is the feature that the ink in the printing element parts of a print rises. Copper plate prints show profound feeling, in addition, its effect of preventing forgery is high. This method is generally called engraving printing, and is used frequently for printing various bills and artistic prints. The electron beam irradiation apparatus installed in the laboratory of the Printing Bureau, Ministry of Finance, is an experimental machine of area beam type, and is so constructed as to do batch conveyance and web conveyance. As the ink in printing element parts rises, the offset at the delivery part of a printing machine becomes a problem. Electron beam is superior in its transparency, and can dry instantaneously to the inside of opaque ink. At 200 kV of acceleration voltage, the ink of copper plate prints can be hardened by electron beam irradiation. The dilution monomers as the vehicle for ink were tested for their dilution capability and the effect of electron beam hardening. The problem in the utilization of electron beam is the deterioration of papers, and the counter-measures were tested. (K.I.)

  4. Zinc containing dental fixative causing copper deficiency myelopathy.

    Science.gov (United States)

    Carroll, Liam Stuart; Abdul-Rahim, Azmil H; Murray, Rosanne

    2017-08-08

    A 62-year-old male, previously well, was referred to neurology clinic following 6 months history of worsening lower limbs instability, paraesthesia, pain and weakness rendering him housebound. Examination revealed upper motor neuron pattern of weakness of the lower limbs and loss of proprioception. Serum analysis revealed reduced caeruloplasmin and copper levels with raised zinc. Spinal imaging revealed subtle dorsal column intensity changes in C2-C7, confirmed with 3T MRI. A copper deficiency myeloneuropathy was diagnosed secondary to chronic use of a zinc-containing dental fixative paste. The paste was discontinued and a copper supplementation was started. Resolution of symptoms was not achieved with intensive physiotherapy. The patient remains a wheelchair user though progression of symptoms has halted. Prompt recognition and treatment of hyperzincaemia-induced hypocupraemia earlier in the disease course may have prevented any irreversible neurological deficit. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  5. Transient Enhanced Diffusion

    Science.gov (United States)

    Gossmann, Hans-Joachim L.

    1996-03-01

    Ion implantation is the standard method for dopant introduction during integrated circuit manufacturing, determining crucial device characteristics. Implantation creates point-defects, such as Si self-interstitials and vacancies, far in excess of equilibrium concentrations. Since the diffusion of common dopants involves Si point defects, the interaction of damage and dopants during subsequent annealing steps leads to the phenomenon known as "transient enhanced diffusion" (TED): The dopant diffusivities are enhanced, possibly by many orders of magnitude. The enhancement is transient since the intrinsic defects eventually diffuse into the bulk or annihilate at the surface. The desired specific dopant profile of the device is thus the result of a complex reaction, involving the creation of damage and its spatial distribution, diffusion, and interaction of the point defects among themselves and with interfaces and other defects. As device dimensions shrink and experiments become more and more expensive, the capability to predict these kinds of non-equilibrium phenomena accurately becomes crucial to Si technology development. In our experiments to extract physical mechanisms and parameters of TED we use the method of sharp B- and Sb doping spikes to track interstitial and vacancy concentrations as a function of depth during processing. Thus we gain sensitivity to small diffusion distances (low temperatures) and separate the damaged region from the region of the interaction with dopants. In addition, our method yields directly the actual point defect diffusivity. Although an ion implant initially produces Frenkel pairs, Monte-carlo simulations show that the vacancies annihilate quickly. The excess interstitials, roughly one for each implanted ion coalesce into 311defects. The subsequent evaporation of interstitials from 311ś drives TED. Si interstitial diffusion is influenced by carbon-related traps and we will demonstrate that this finding reconciles quantitatively a

  6. Radiation induced structural changes in alpha-copper-zinc alloys

    International Nuclear Information System (INIS)

    Schuele, W.; Gieb, M.

    1991-01-01

    During irradiation of alpha-copper-zinc alloys with high energy electrons and protons a decrease of the electrical resistivity due to an increase of the degree of short range order is observed through radiation enhanced diffusion followed by an increase of the electrical resistivity through the formation of radiation induced interstitial clusters. The initial formation rate of interstitial clusters increases about linearly with the displacement rate for electron and proton irradiation. The largest initial formation rate is found between 60 and 130 0 C becoming negligibly small above 158 0 C and decreases drastically below 60 0 C. The dynamic steady state interstitial cluster concentration increases with decreasing irradiation temperature in the investigated temperature range between 158 and 40 0 C. Above 158 0 C the formation rate of interstitial clusters is negligibly small. Thus the transition temperature for radiation induced interstitial cluster formation is 158 0 C, depending mainly on the migration activation energy of vacancies. The radiation induced interstitial clusters are precipitates in those alloys in which the diffusion rate of the undersized component atoms via an interstitialcy diffusion mechanism is larger than that of the other atoms

  7. Performance characteristics, plasma lipids and copper residue in ...

    African Journals Online (AJOL)

    Copper proteinate) and inorganic (Copper sulphate) Cu source on growth performance, plasma lipids and copper residue in organs and tissues of cockerel chickens. 240 day-old commercial Black-Harco cockerel chicks were randomly distributed to ...

  8. Copper Electroforming at the Canfranc Underground Laboratory. Status Report

    International Nuclear Information System (INIS)

    Borjabad, S.; Amare, J.; Morales, J.; Ortiz de Solorzano, A.; Villar, J. A.

    2007-01-01

    A brief summary of the copper electroforming process is given. The process parameters tuning to attain a copper part with the required characteristics is explained. Several electroformed copper parts with complicated geometry are described. Some radiopurity measurements are provided

  9. Lead diffusion in monazite

    International Nuclear Information System (INIS)

    Gardes, E.

    2006-06-01

    Proper knowledge of the diffusion rates of lead in monazite is necessary to understand the U-Th-Pb age anomalies of this mineral, which is one of the most used in geochronology after zircon. Diffusion experiments were performed in NdPO 4 monocrystals and in Nd 0.66 Ca 0.17 Th 0.17 PO 4 polycrystals from Nd 0.66 Pb 0.17 Th 0.17 PO 4 thin films to investigate Pb 2+ + Th 4+ ↔ 2 Nd 3+ and Pb 2+ ↔ Ca 2+ exchanges. Diffusion annealings were run between 1200 and 1500 Celsius degrees, at room pressure, for durations ranging from one hour to one month. The diffusion profiles were analysed using TEM (transmission electronic microscopy) and RBS (Rutherford backscattering spectroscopy). The diffusivities extracted for Pb 2+ + Th 4+ ↔ 2 Nd 3+ exchange follow an Arrhenius law with parameters E equals 509 ± 24 kJ mol -1 and log(D 0 (m 2 s -1 )) equals -3.41 ± 0.77. Preliminary data for Pb 2+ ↔ Ca 2+ exchange are in agreement with this result. The extrapolation of our data to crustal temperatures yields very slow diffusivities. For instance, the time necessary for a 50 μm grain to lose all of its lead at 800 Celsius degrees is greater than the age of the Earth. From these results and other evidence from the literature, we conclude that most of the perturbations in U-Th-Pb ages of monazite cannot be attributed to lead diffusion, but rather to interactions with fluids. (author)

  10. Mechanisms and energetics of surface reactions at the copper-water interface. A critical literature review with implications for the debate on corrosion of copper in anoxic water

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Adam Johannes; Brinck, Tore [Applied Physical Chemistry, KTH Royal Inst. of Technology, Stockholm (Sweden)

    2012-06-15

    In order to make a critical analysis of the discussion of corrosion of copper in pure anoxic water it is necessary to understand the chemical reactivity at the copper-water interface. Even though the most fundamental issue, i.e. the nature and existence of a hypothetical product that is thermodynamically stable, is still under debate, it is clear that if anoxic corrosion really exists, it must be initiated through oxidative surface reactions at the copper-water interface. This report presents a survey of the peer reviewed literature on the reactivity of copper surfaces in water. Reactions discussed involve molecular adsorption of water, dissociation of the OH-bonds in adsorbed water molecules and hydroxyl groups, the disproportionation/synproportionation equilibrium between hydroxyl groups/hydroxide ions, water molecules and atomic oxygen, the surface diffusion of adsorbed species, and the formation of hydrogen gas (molecular hydrogen). Experimental, as well as theoretical (quantum chemical) studies are reviewed. It is concluded that a limited amount of hydrogen gas (H{sub 2}) should be formed as the result of dissociative water adsorption at certain copper surfaces. Quantitative estimates of the amounts of H2 that could form at the copper-water interface are made. Assuming that the water-cleavage/hydrogen-formation reaction proceeds on an ideal [110] or [100] surface until a hydroxyl monolayer (ML) is reached, the amount of H{sub 2} formed is {approx} 2.4 ng cm{sup -2} copper surface. Based on the literature cited, this is most likely possible, thermodynamically as well as kinetically. Although not proven, it is not unlikely that the reaction can proceed until an oxide ML is formed, which would give 4.8 ng cm{sup -2}. If the formation of an oxide ML is thermodynamically feasible the surface will probably react further, since Cu{sub 2}O(s) is known to activate and cleave the water molecule when it adsorbs at the Cu{sub 2}O(s) surface. Assuming the formation of a

  11. Removal of Copper ions from aqueous solutions using polymer derivations of poly (styrene-alt-maleic anhydride

    Directory of Open Access Journals (Sweden)

    Naser Samadi

    2017-06-01

    Full Text Available In this study chelating resins have been considered to be suitable materials for the recovery of Copper (II ions in water treatments. Furthermore, these modified resins were reacted with 1,2-diaminoethane in the presence of ultrasonic irradiation for the preparation of a tridimensional chelating resin on the Nano scale for the recovery of Copper (II ions from aqueous solutions. This method which is used for removing and determining Copper (II ions using copolymers derived resins of poly (styrene-alternative-maleic anhydride (SMA and atomic absorption spectroscopy. The method is simple, sensitive, inexpensive and fast. The various parameters such as pH, contact time, concentrations of metal ions, mass of resin, and agitation speed were investigated on adsorption effect. The adsorption behavior of Copper (II ions were investigated by the synthesis of chelating resins at various pHs. The prepared resins showed a good tendency for removing the selected metal ions from aqueous solution, even at an acidic pH. Also, the prepared resins were examined for the removal of Copper (II ions from real samples such as industrial wastewater and were shown to be very efficient at adsorption in the cases of Copper (II ions. The pseudo-first-order, pseudo-second-order, and intra-particle diffusion kinetics equations were used for modeling of adsorption data and it was shown that pseudo-second-order kinetic equation could best describe the adsorption kinetics. The intra-particle diffusion study revealed that external diffusion might be involved in this case. The resins were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction analysis.

  12. Influence of copper ions on the viability and cytotoxicity of Pseudomonas aeruginosa under conditions relevant to drinking water environments.

    Science.gov (United States)

    Dwidjosiswojo, Zenyta; Richard, Jessica; Moritz, Miriam M; Dopp, Elke; Flemming, Hans-Curt; Wingender, Jost

    2011-11-01

    Copper plumbing materials can be the source of copper ions in drinking water supplies. The aim of the current study was to investigate the influence of copper ions on the viability and cytotoxicity of the potential pathogen Pseudomonas aeruginosa that presents a health hazard when occurring in building plumbing systems. In batch experiments, exposure of P. aeruginosa (10(6)cells/mL) for 24h at 20°C to copper-containing drinking water from domestic plumbing systems resulted in a loss of culturability, while total cell numbers determined microscopically did not decrease. Addition of the chelator diethyldithiocarbamate (DDTC) to copper-containing water prevented the loss of culturability. When suspended in deionized water with added copper sulfate (10 μM), the culturability of P. aeruginosa decreased by more than 6 log units, while total cell counts, the concentration of cells with intact cytoplasmic membranes, determined with the LIVE/DEAD BacLight kit, and the number of cells with intact 16S ribosomal RNA, determined by fluorescent in situ hybridization, remained unchanged. When the chelator DDTC was added to copper-stressed bacteria, complete restoration of culturability was observed to occur within 14 d. Copper-stressed bacteria were not cytotoxic towards Chinese hamster ovary (CHO-9) cells, while untreated and resuscitated bacteria caused an almost complete decrease of the concentration of viable CHO-9 cells within 24 h. Thus, copper ions in concentrations relevant to drinking water in plumbing systems seem to induce a viable but non-culturable (VBNC) state in P. aeruginosa accompanied by a loss of culturability and cytotoxicity, and VBNC cells can regain both culturability and cytotoxicity, when copper stress is abolished. Copyright © 2011 Elsevier GmbH. All rights reserved.

  13. Investigation on dissimilar underwater friction stir lap welding of 6061-T6 aluminum alloy to pure copper

    International Nuclear Information System (INIS)

    Zhang, Jingqing; Shen, Yifu; Yao, Xin; Xu, Haisheng; Li, Bo

    2014-01-01

    Highlights: • 6061-T6 Al and pure Cu were successfully underwater friction stir lap welded. • The underwater weld was analyzed via comparing with the classical weld. • The oxidation of Cu was prevented via the external water. • The amount of Al–Cu intermetallic was decreased by the external water. • The thickness of Al–Cu diffusion interlayer was decreased by the external water. - Abstract: Friction stir welding (classical FSW) is considered to offer advantages over the traditional fusion welding techniques in terms of dissimilar welding. However, some challenges still exist in the dissimilar friction stir lap welding of the aluminum/copper (Al/Cu) metallic couple, among which the formation of the Al–Cu intermetallic compounds is the major problem. In the present research, due to the fact that the formation and growth of the intermetallic are significantly controlled by the thermal history, the underwater friction stir welding (underwater FSW) was employed for fabricating the weld, and the weld obtained by underwater FSW (underwater weld) was analyzed via comparing with the weld obtained under same parameters by classical FSW (classical weld). In order to investigate the effect of the external water on the thermal history, the K-type thermocouple was utilized to measure the weld temperature, and it is found that the water could decrease the peak temperature and shorten the thermal cycle time. The XRD results illustrate that the interface of the welds mainly consist of the Al–Cu intermetallic compounds such as CuAl 2 and Cu 9 Al 4 together with some amounts of Al and Cu, and it is also found that the amount of the intermetallic in the underwater weld is obvious less than in the classical weld. The SEM images and the EDS line scan results also illustrate that the Al–Cu diffusion interlayer at the Al–Cu interface of the underwater weld was obviously thinner than that of the classical weld

  14. Anomalous Diffusion Near Resonances

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Tanaji; /Fermilab

    2010-05-01

    Synchro-betatron resonances can lead to emittance growth and the loss of luminosity. We consider the detailed dynamics of a bunch near such a low order resonance driven by crossing angles at the collision points. We characterize the nature of diffusion and find that it is anomalous and sub-diffusive. This affects both the shape of the beam distribution and the time scales for growth. Predictions of a simplified anomalous diffusion model are compared with direct simulations. Transport of particles near resonances is still not a well understood phenomenon. Often, without justification, phase space motion is assumed to be a normal diffusion process although at least one case of anomalous diffusion in beam dynamics has been reported [1]. Here we will focus on the motion near synchro-betatron resonances which can be excited by several means, including beams crossing at an angle at the collision points as in the LHC. We will consider low order resonances which couple the horizontal and longitudinal planes, both for simplicity and to observe large effects over short time scales. While the tunes we consider are not practical for a collider, nonetheless the transport mechanisms we uncover are also likely to operate at higher order resonances.

  15. Annual Copper Mountain Conferences on Multigrid and Iterative Methods, Copper Mountain, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, Stephen F. [Front Range Scientific, Inc., Lake City, CO (United States)

    2016-03-25

    This project supported the Copper Mountain Conference on Multigrid and Iterative Methods, held from 2007 to 2015, at Copper Mountain, Colorado. The subject of the Copper Mountain Conference Series alternated between Multigrid Methods in odd-numbered years and Iterative Methods in even-numbered years. Begun in 1983, the Series represents an important forum for the exchange of ideas in these two closely related fields. This report describes the Copper Mountain Conference on Multigrid and Iterative Methods, 2007-2015. Information on the conference series is available at http://grandmaster.colorado.edu/~copper/.

  16. Annual Copper Mountain Conferences on Multigrid and Iterative Methods, Copper Mountain, Colorado

    International Nuclear Information System (INIS)

    McCormick, Stephen F.

    2016-01-01

    This project supported the Copper Mountain Conference on Multigrid and Iterative Methods, held from 2007 to 2015, at Copper Mountain, Colorado. The subject of the Copper Mountain Conference Series alternated between Multigrid Methods in odd-numbered years and Iterative Methods in even-numbered years. Begun in 1983, the Series represents an important forum for the exchange of ideas in these two closely related fields. This report describes the Copper Mountain Conference on Multigrid and Iterative Methods, 2007-2015. Information on the conference series is available at http://grandmaster.colorado.edu/~copper/

  17. Diffusion Bonding Beryllium to Reduced Activation Ferritic Martensitic Steel: Development of Processes and Techniques

    Science.gov (United States)

    Hunt, Ryan Matthew

    Only a few materials are suitable to act as armor layers against the thermal and particle loads produced by magnetically confined fusion. These candidates include beryllium, tungsten, and carbon fiber composites. The armor layers must be joined to the plasma facing components with high strength bonds that can withstand the thermal stresses resulting from differential thermal expansion. While specific joints have been developed for use in ITER (an experimental reactor in France), including beryllium to CuCrZr as well as tungsten to stainless steel interfaces, joints specific to commercially relevant fusion reactors are not as well established. Commercial first wall components will likely be constructed front Reduced Activation Ferritic Martensitic (RAFM) steel, which will need to be coating with one of the three candidate materials. Of the candidates, beryllium is particularly difficult to bond, because it reacts during bonding with most elements to form brittle intermetallic compounds. This brittleness is unacceptable, as it can lead to interface crack propagation and delamination of the armor layer. I have attempted to overcome the brittle behavior of beryllium bonds by developing a diffusion bonding process of beryllium to RAFM steel that achieves a higher degree of ductility. This process utilized two bonding aids to achieve a robust bond: a. copper interlayer to add ductility to the joint, and a titanium interlayer to prevent beryllium from forming unwanted Be-Cu intermetallics. In addition, I conducted a series of numerical simulations to predict the effect of these bonding aids on the residual stress in the interface. Lastly, I fabricated and characterized beryllium to ferritic steel diffusion bonds using various bonding parameters and bonding aids. Through the above research, I developed a process to diffusion bond beryllium to ferritic steel with a 150 M Pa tensile strength and 168 M Pa shear strength. This strength was achieved using a Hot Isostatic

  18. Energy and materials flows in the copper industry

    Energy Technology Data Exchange (ETDEWEB)

    Gaines, L.L.

    1980-12-01

    The copper industry comprises both the primary copper industry, which produces 99.9%-pure copper from copper ore, and the secondary copper industry, which salvages and recycles copper-containing scrap metal to extract pure copper or copper alloys. The United States uses about 2 million tons of copper annually, 60% of it for electrical applications. Demand is expected to increase less than 4% annually for the next 20 years. The primary copper industry is concentrated in the Southwest; Arizona produced 66% of the 1979 total ore output. Primary production uses about 170 x 10/sup 12/ Btu total energy annually (about 100 x 10/sup 6/ Btu/ton pure copper produced from ore). Mining and milling use about 60% of the total consumption, because low-grade ore (0.6% copper) is now being mined. Most copper is extracted by smelting sulfide ores, with concomitant production of sulfur dioxide. Clean air regulations will require smelters to reduce sulfur emissions, necessitating smelting process modifications that could also save 20 x 10/sup 12/ Btu (10 x 10/sup 6/ Btu/ton of copper) in smelting energy. Energy use in secondary copper production averages 20 x 10/sup 6/ Btu/ton of copper. If all copper products were recycled, instead of the 30% now salvaged, the energy conservation potential would be about one-half the total energy consumption of the primary copper industry.

  19. Joining silicon carbide to austenitic stainless steel through diffusion welding; Stellingen behorende bij het proefschrift

    Energy Technology Data Exchange (ETDEWEB)

    Krugers, Jan-Paul

    1993-01-19

    In this thesis, the results are presented of a study dealing with joining silicon carbide to austenitic stainless steel AIS316 by means of diffusion welding. Welding experiments were carried out without and with the use of a metallic intermediate, like copper, nickel and copper-nickel alloys at various conditions of process temperature, process time, mechanical pressure and interlayer thickness. Most experiments were carried out in high vacuum. For reasons of comparison, however, some experiments were also carried out in a gas shielded environment of 95 vol.% Ar and 5 vol.% H2.

  20. Copper-complexing ligands produced by an intact estuarine microbial community in response to copper stress.

    Science.gov (United States)

    Bingham, J.; Dryden, C.; Gordon, A.

    2002-12-01

    Copper is both an important nutrient and a pollutant in the marine environment. By studying the interactions between microorganisms and copper in the Elizabeth River (VA), home to a major Naval Base, we field tested the hypothesis that picoplankton and/or bacterioplankton produce strong, copper-complexing ligands in response to elevated copper concentrations. A simple light/ dark test was used to distinguish between heterotrophic and phototrophic ligand production. Samples were bottled and moored, submerged one meter, for a week. Direct counts using DAPI stain and epiflourescence were conducted to find concentrations of picoplankton and bacterioplankton. Using cathodic stripping voltammetry, we found the total copper concentrations, and then from a titration of the ligands by copper, the ligand concentrations and conditional stability constants were obtained. The Elizabeth River naturally had between 10-20 nM total dissolved copper concentrations. However when copper complexation was considered we found that the levels of bio-available Cu(II) ions were much lower. In fact in the natural samples the levels were not high enough to affect the relative reproductive rates of several microorganisms. Naturally there was a 50 nM "buffer zone" of ligand to total dissolved copper concentration. Furthermore, when stressed with excess copper, healthy picoplankton produced enough ligand to alleviate toxicity, and rebuild the buffer zone. However bacterioplankton only produced enough ligand so that they were no longer affected. Therefore, intact estuarine communities regulate copper bioavailability and toxicity with ligand production.

  1. COPPER AND COPPER-CONTAINING PESTICIDES: METABOLISM, TOXICITY AND OXIDATIVE STRESS

    Directory of Open Access Journals (Sweden)

    Viktor Husak

    2015-05-01

    Full Text Available The purpose of this paper is to provide a brief review of the current knowledge regarding metabolism and toxicity of copper and copper-based pesticides in living organisms. Copper is an essential trace element in all living organisms (bacteria, fungi, plants, and animals, because it participates in different metabolic processes and maintain functions of organisms. The transport and metabolism of copper in living organisms is currently the subject of many studies. Copper is absorbed, transported, distributed, stored, and excreted in the body via the complex of homeostatic processes, which provide organisms with a needed constant level of this micronutrient and avoid excessive amounts. Many aspects of copper homeostasis were studied at the molecular level. Copper based-pesticides, in particularly fungicides, bacteriocides and herbicides, are widely used in agricultural practice throughout the world. Copper is an integral part of antioxidant enzymes, particularly copper-zinc superoxide dismutase (Cu,Zn-SOD, and plays prominent roles in iron homeostasis. On the other hand, excess of copper in organism has deleterious effect, because it stimulates free radical production in the cell, induces lipid peroxidation, and disturbs the total antioxidant capacity of the body. The mechanisms of copper toxicity are discussed in this review also.

  2. Distributed Control Diffusion

    DEFF Research Database (Denmark)

    Schultz, Ulrik Pagh

    2007-01-01

    . Programming a modular, self-reconfigurable robot is however a complicated task: the robot is essentially a real-time, distributed embedded system, where control and communication paths often are tightly coupled to the current physical configuration of the robot. To facilitate the task of programming modular....... This approach allows the programmer to dynamically distribute behaviors throughout a robot and moreover provides a partial abstraction over the concrete physical shape of the robot. We have implemented a prototype of a distributed control diffusion system for the ATRON modular, self-reconfigurable robot......, self-reconfigurable robots, we present the concept of distributed control diffusion: distributed queries are used to identify modules that play a specific role in the robot, and behaviors that implement specific control strategies are diffused throughout the robot based on these role assignments...

  3. Cesium diffusion in graphite

    International Nuclear Information System (INIS)

    Evans, R.B. III; Davis, W. Jr.; Sutton, A.L. Jr.

    1980-05-01

    Experiments on diffusion of 137 Cs in five types of graphite were performed. The document provides a completion of the report that was started and includes a presentation of all of the diffusion data, previously unpublished. Except for data on mass transfer of 137 Cs in the Hawker-Siddeley graphite, analyses of experimental results were initiated but not completed. The mass transfer process of cesium in HS-1-1 graphite at 600 to 1000 0 C in a helium atmosphere is essentially pure diffusion wherein values of (E/epsilon) and ΔE of the equation D/epsilon = (D/epsilon) 0 exp [-ΔE/RT] are about 4 x 10 -2 cm 2 /s and 30 kcal/mole, respectively

  4. Apparatus for diffusion separation

    International Nuclear Information System (INIS)

    Nierenberg, W.A.; Pontius, R.B.

    1976-01-01

    The method of testing the separation efficiency of porous permeable membranes is described which comprises causing a stream of a gaseous mixture to flow into contact with one face of a finely porous permeable membrane under such conditions that a major fraction of the mixture diffuses through the membrane, maintaining a rectangular cross section of the gaseous stream so flowing past said membrane, continuously recirculating the gas that diffuses through said membrane and continuously withdrawing the gas that does not diffuse through said membrane and maintaining the volume of said recirculating gas constant by continuously introducing into said continuously recirculating gas stream a mass of gas equivalent to that which is continuously withdrawn from said gas stream and comparing the concentrations of the light component in the entering gas, the withdrawn gas and the recirculated gas in order to determine the efficiency of said membrane

  5. Diffusion in flexible pipes

    Energy Technology Data Exchange (ETDEWEB)

    Brogaard Kristensen, S.

    2000-06-01

    This report describes the work done on modelling and simulation of the complex diffusion of gas through the wall of a flexible pipe. The diffusion and thus the pressure in annulus depends strongly on the diffusion and solubility parameters of the gas-polymer system and on the degree of blocking of the outer surface of the inner liner due to pressure reinforcements. The report evaluates the basis modelling required to describe the complex geometries and flow patterns. Qualitatively results of temperature and concentration profiles are shown in the report. For the program to serve any modelling purpose in 'real life' the results need to be validated and possibly the model needs corrections. Hopefully, a full-scale test of a flexible pipe will provide the required temperatures and pressures in annulus to validate the models. (EHS)

  6. Diffusion and mass transfer

    CERN Document Server

    Vrentas, James S

    2013-01-01

    The book first covers the five elements necessary to formulate and solve mass transfer problems, that is, conservation laws and field equations, boundary conditions, constitutive equations, parameters in constitutive equations, and mathematical methods that can be used to solve the partial differential equations commonly encountered in mass transfer problems. Jump balances, Green’s function solution methods, and the free-volume theory for the prediction of self-diffusion coefficients for polymer–solvent systems are among the topics covered. The authors then use those elements to analyze a wide variety of mass transfer problems, including bubble dissolution, polymer sorption and desorption, dispersion, impurity migration in plastic containers, and utilization of polymers in drug delivery. The text offers detailed solutions, along with some theoretical aspects, for numerous processes including viscoelastic diffusion, moving boundary problems, diffusion and reaction, membrane transport, wave behavior, sedime...

  7. Surface Structures Formed by a Copper(II Complex of Alkyl-Derivatized Indigo

    Directory of Open Access Journals (Sweden)

    Akinori Honda

    2016-10-01

    Full Text Available Assembled structures of dyes have great influence on their coloring function. For example, metal ions added in the dyeing process are known to prevent fading of color. Thus, we have investigated the influence of an addition of copper(II ion on the surface structure of alkyl-derivatized indigo. Scanning tunneling microscope (STM analysis revealed that the copper(II complexes of indigo formed orderly lamellar structures on a HOPG substrate. These lamellar structures of the complexes are found to be more stable than those of alkyl-derivatized indigos alone. Furthermore, 2D chirality was observed.

  8. Electro-oxidation of methanol on copper in alkaline solution

    International Nuclear Information System (INIS)

    Heli, H.; Jafarian, M.; Mahjani, M.G.; Gobal, F.

    2004-01-01

    The electro-oxidation of methanol on copper in alkaline solutions has been studied by the methods of cyclic voltammetry, quasi-steady state polarization and chronoamperometry. It has been found that in the course of an anodic potential sweep the electro-oxidation of methanol follows the formation of Cu III and is catalysed by this species through a mediated electron transfer mechanism. The reaction also continues in the early stages of the reversed cycle until it is stopped by the prohibitively negative potentials. The process is diffusion controlled and the current-time responses follow Cottrellian behavior. The rate constants, turnover frequency, anodic transfer coefficient and the apparent activation energy of the electro-oxidation reaction are reported

  9. Plasma Copper Status in Hypercholesterolemic Patients

    African Journals Online (AJOL)

    Dr Femi Olaleye

    ... Rosenstein, F., and Lei, K.Y.. (1994): Pool size and concentration of plasma cholesterol are increased and tissue copper levels are reduced during early stages of copper deficiency in rats. J. Nutr. 124, 628-635. Anon (2000): Cardiovascular disease ranks as the first cause of death in Spain. Rev Esp Salud Publica 74 (3),.

  10. Extra-Hepatic Storage of Copper

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Damsgaard, Else; Horn, N.

    1975-01-01

    The distribution of copper among the organs of an aborted, male foetus, expected to develop Menkes' syndrome, was entirely different from the distribution in 4 normal foetuses. Copper concentrations determined by neutron activation analysis showed a considerably reduced content in the liver, but ...

  11. Material characterization of ancient Indian copper

    Indian Academy of Sciences (India)

    Keywords. Ancient Indian copper; material characterization; electrochemical behaviour; rust analysis; corrosion rate. Abstract. A chalcolithic (2350–1800 BC) copper chisel from Balathal has been characterized by X-ray diffraction, microstructural and electrochemical methods. The surface patina was composed of sulfates ...

  12. Pharmacological Properties of Nanometals (Silver, Copper, Iron)

    OpenAIRE

    Chekman, I.S.

    2015-01-01

    The article summarizes the results of studies on the pharmacological, toxicological and specific properties of nanometals (silver, iron, copper). It is established that nanoparticles of silver, copper, iron exhibit antimicrobial action. Acute toxicity of nanometals depends on their nature, administration route and animal sex. Effects on heart activity and hemodynamic status as well as erythrocyte osmotic fragility have dose-dependent nature.

  13. Copper laser diagnostics and kinetics support

    International Nuclear Information System (INIS)

    1981-12-01

    In the effort MSNW participated with the LINL copper-Vapor Laser Program by providing a useful plasma diagnostic for interpretation of Copper-vapor laser kinetics. MSNW developed and delivered a pulsed interferometric diagnostic package to LLNL. Moreover MSNW provided personal services at the request and direction of LLL in the implementation of the diagnostic and interpretation of the data

  14. Differential bacteriophage mortality on exposure to copper.

    Science.gov (United States)

    Li, Jinyu; Dennehy, John J

    2011-10-01

    Many studies report that copper can be used to control microbial growth, including that of viruses. We determined the rates of copper-mediated inactivation for a wide range of bacteriophages. We used two methods to test the effect of copper on bacteriophage survival. One method involved placing small volumes of bacteriophage lysate on copper and stainless steel coupons. Following exposure, metal coupons were rinsed with lysogeny broth, and the resulting fluid was serially diluted and plated on agar with the corresponding bacterial host. The second method involved adding copper sulfate (CuSO(4)) to bacteriophage lysates to a final concentration of 5 mM. Aliquots were removed from the mixture, serially diluted, and plated with the appropriate bacterial host. Significant mortality was observed among the double-stranded RNA (dsRNA) bacteriophages Φ6 and Φ8, the single-stranded RNA (ssRNA) bacteriophage PP7, the ssDNA bacteriophage ΦX174, and the dsDNA bacteriophage PM2. However, the dsDNA bacteriophages PRD1, T4, and λ were relatively unaffected by copper. Interestingly, lipid-containing bacteriophages were most susceptible to copper toxicity. In addition, in the first experimental method, the pattern of bacteriophage Φ6 survival over time showed a plateau in mortality after lysates dried out. This finding suggests that copper's effect on bacteriophage is mediated by the presence of water.

  15. Mixed-ligand binuclear copper(II)

    Indian Academy of Sciences (India)

    A new mixed-ligand binuclear copper(II) complex [Cu(MS)(bpy)]2.(ClO4)2, built of 5-methylsalicylaldehyde and 2,2'-bipyridyl has been synthesized and characterized by using elemental analysis, IR and UV-Vis spectroscopy. Crystal structure of the complex shows that copper(II) ion lies in a square pyramidal coordination ...

  16. Copper transporters and chaperones: Their function on ...

    Indian Academy of Sciences (India)

    2016-08-02

    Aug 2, 2016 ... This micronutrient is necessary for the proper growth, development and maintenance of connective tissue, bone, brain and heart. Copper is found to ... Wilson's disease. (WD) is a monogenic, autosomal, recessive inherited disor- der where the copper ATPase, ATP7B, is a major causative gene (Tanzi et al.

  17. Copper Regulates Cyclic AMP-Dependent Lipolysis

    Science.gov (United States)

    Krishnamoorthy, Lakshmi; Cotruvo, Joseph A.; Chan, Jefferson; Kaluarachchi, Harini; Muchenditsi, Abigael; Pendyala, Venkata S.; Jia, Shang; Aron, Allegra T.; Ackerman, Cheri M.; Vander Wal, Mark N.; Guan, Timothy; Smaga, Lukas P.; Farhi, Samouil L.; New, Elizabeth J.; Lutsenko, Svetlana; Chang, Christopher J.

    2016-01-01

    Cell signaling relies extensively on dynamic pools of redox-inactive metal ions such as sodium, potassium, calcium, and zinc, but their redox-active transition metal counterparts such as copper and iron have been studied primarily as static enzyme cofactors. Here we report that copper is an endogenous regulator of lipolysis, the breakdown of fat, which is an essential process in maintaining the body's weight and energy stores. Utilizing a murine model of genetic copper misregulation, in combination with pharmacological alterations in copper status and imaging studies in a 3T3-L1 white adipocyte model, we demonstrate that copper regulates lipolysis at the level of the second messenger, cyclic AMP (cAMP), by altering the activity of the cAMP-degrading phosphodiesterase PDE3B. Biochemical studies of the copper-PDE3B interaction establish copper-dependent inhibition of enzyme activity and identify a key conserved cysteine residue within a PDE3-specific loop that is essential for the observed copper-dependent lipolytic phenotype. PMID:27272565

  18. High Copper Amalgam Alloys in Dentistry

    Directory of Open Access Journals (Sweden)

    Gaurav Solanki

    2012-07-01

    Full Text Available Amalgam Restoration is an example of the material giving its name to the process. Amalgam fillings are made up of mercury, powdered silver and tin. They are mixed and packed into cavities in teeth where it hardens slowly and replaces the missing tooth substance. The high copper have become material of choice as compared to low copper alloys nowadays because of their improved mechanical properties, corrosion resistance, better marginal integrity and improved performance in clinical trial. The high copper amalgam was used as a restorative material. The application of high copper amalgam was found to be much more useful than low copper amalgam. High copper had much more strength, corrosion resistance, durability and resistance to tarnish as compared to low copper amalgams. No marked expansion or condensation was noted in the amalgam restoration after its setting after 24 hrs. By using the high copper alloy, the chances of creep were also minimized in the restored tooth. No discomfort or any kind of odd sensation in the tooth was noted after few days of amalgam restoration in the tooth.

  19. Lead and Copper Control 101-slides

    Science.gov (United States)

    This presentation is an overview of the most important water treatment strategies for the control of lead and copper release from drinking water corrosion. In addition to the sections specifically on lead and copper treatment, sections are included that cover sampling to find le...

  20. Synthesis and optical characterization of copper nanoparticles ...

    Indian Academy of Sciences (India)

    Hence, copper (Cu) colloidal NPs were prepared using laser ablation (Nd:YAG, ... Copper nanoparticles; optical property; LSPR, laser ablation. 1. Introduction. Among all nanomaterials, nanoparticles (NPs) are of great interest because of their optical, structural, ... useful for applications in a wide range of fields like can-.

  1. Mercury Amalgam Diffusion in Human Teeth Probed Using Femtosecond LIBS.

    Science.gov (United States)

    Bello, Liciane Toledo; da Ana, Patricia Aparecida; Santos, Dário; Krug, Francisco José; Zezell, Denise Maria; Vieira, Nilson Dias; Samad, Ricardo Elgul

    2017-04-01

    In this work the diffusion of mercury and other elements from amalgam tooth restorations through the surrounding dental tissue (dentin) was evaluated using femtosecond laser-induced breakdown spectroscopy (fs-LIBS). To achieve this, seven deciduous and eight permanent extracted human molar teeth with occlusal amalgam restorations were half-sectioned and analyzed using pulses from a femtosecond laser. The measurements were performed from the amalgam restoration along the amalgam/dentin interface to the apical direction. It was possible to observe the presence of metallic elements (silver, mercury, copper and tin) emission lines, as well as dental constituent ones, providing fingerprints of each material and comparable data for checking the consistence of the results. It was also shown that the elements penetration depth values in each tooth are usually similar and consistent, for both deciduous and permanent teeth, indicating that all the metals diffuse into the dentin by the same mechanism. We propose that this diffusion mechanism is mainly through liquid dragging inside the dentin tubules. The mercury diffused further in permanent teeth than in deciduous teeth, probably due to the longer diffusion times due to the age of the restorations. It was possible to conclude that the proposed femtosecond-LIBS system can detect the presence of metals in the dental tissue, among the tooth constituent elements, and map the distribution of endogenous and exogenous chemical elements, with a spatial resolution that can be brought under 100 µm.

  2. The Trouble with Diffusion

    Directory of Open Access Journals (Sweden)

    R.T. DeHoff

    2002-09-01

    Full Text Available The phenomenological formalism, which yields Fick's Laws for diffusion in single phase multicomponent systems, is widely accepted as the basis for the mathematical description of diffusion. This paper focuses on problems associated with this formalism. This mode of description of the process is cumbersome, defining as it does matrices of interdiffusion coefficients (the central material properties that require a large experimental investment for their evaluation in three component systems, and, indeed cannot be evaluated for systems with more than three components. It is also argued that the physical meaning of the numerical values of these properties with respect to the atom motions in the system remains unknown. The attempt to understand the physical content of the diffusion coefficients in the phenomenological formalism has been the central fundamental problem in the theory of diffusion in crystalline alloys. The observation by Kirkendall that the crystal lattice moves during diffusion led Darken to develop the concept of intrinsic diffusion, i.e., atom motion relative to the crystal lattice. Darken and his successors sought to relate the diffusion coefficients computed for intrinsic fluxes to those obtained from the motion of radioactive tracers in chemically homogeneous samples which directly report the jump frequencies of the atoms as a function of composition and temperature. This theoretical connection between tracer, intrinsic and interdiffusion behavior would provide the basis for understanding the physical content of interdiffusion coefficients. Definitive tests of the resulting theoretical connection have been carried out for a number of binary systems for which all three kinds of observations are available. In a number of systems predictions of intrinsic coefficients from tracer data do not agree with measured values although predictions of interdiffusion coefficients appear to give reasonable agreement. Thus, the complete

  3. Hydrogen diffusion in Zircon

    Science.gov (United States)

    Ingrin, Jannick; Zhang, Peipei

    2016-04-01

    Hydrogen mobility in gem quality zircon single crystals from Madagascar was investigated through H-D exchange experiments. Thin slices were annealed in a horizontal furnace flushed with a gas mixture of Ar/D2(10%) under ambient pressure between 900 ° C to 1150 ° C. FTIR analyses were performed on oriented slices before and after each annealing run. H diffusion along [100] and [010] follow the same diffusion law D = D0exp[-E /RT], with log D0 = 2.24 ± 1.57 (in m2/s) and E = 374 ± 39 kJ/mol. H diffusion along [001] follows a slightly more rapid diffusion law, with log D0 = 1.11 ± 0.22 (in m2/s) and E = 334 ± 49 kJ/mol. H diffusion in zircon has much higher activation energy and slower diffusivity than other NAMs below 1150 ° C even iron-poor garnets which are known to be among the slowest (Blanchard and Ingrin, 2004; Kurka et al. 2005). During H-D exchange zircon incorporates also deuterium. This hydration reaction involves uranium reduction as it is shown from the exchange of U5+ and U4+ characteristic bands in the near infrared region during annealing. It is the first time that a hydration reaction U5+ + OH- = U4+ + O2- + 1/2H2, is experimentally reported. The kinetics of deuterium incorporation is slightly slower than hydrogen diffusion, suggesting that the reaction is limited by hydrogen mobility. Hydrogen isotopic memory of zircon is higher than other NAMs. Zircons will be moderately retentive of H signatures at mid-crustal metamorphic temperatures. At 500 ° C, a zircon with a radius of 300 μm would retain its H isotopic signature over more than a million years. However, a zircon is unable to retain this information for geologically significant times under high-grade metamorphism unless the grain size is large enough. Refrences Blanchard, M. and Ingrin, J. (2004) Hydrogen diffusion in Dora Maira pyrope. Physics and Chemistry of Minerals, 31, 593-605. Kurka, A., Blanchard, M. and Ingrin, J. (2005) Kinetics of hydrogen extraction and deuteration in

  4. Phase transformation and diffusion

    CERN Document Server

    Kale, G B; Dey, G K

    2008-01-01

    Given that the basic purpose of all research in materials science and technology is to tailor the properties of materials to suit specific applications, phase transformations are the natural key to the fine-tuning of the structural, mechanical and corrosion properties. A basic understanding of the kinetics and mechanisms of phase transformation is therefore of vital importance. Apart from a few cases involving crystallographic martensitic transformations, all phase transformations are mediated by diffusion. Thus, proper control and understanding of the process of diffusion during nucleation, g

  5. Drift in Diffusion Gradients

    Directory of Open Access Journals (Sweden)

    Fabio Marchesoni

    2013-08-01

    Full Text Available The longstanding problem of Brownian transport in a heterogeneous quasi one-dimensional medium with space-dependent self-diffusion coefficient is addressed in the overdamped (zero mass limit. A satisfactory mesoscopic description is obtained in the Langevin equation formalism by introducing an appropriate drift term, which depends on the system macroscopic observables, namely the diffuser concentration and current. The drift term is related to the microscopic properties of the medium. The paradoxical existence of a finite drift at zero current suggests the possibility of designing a Maxwell demon operating between two equilibrium reservoirs at the same temperature.

  6. Nonlinear diffusion equations

    CERN Document Server

    Wu Zhuo Qun; Li Hui Lai; Zhao Jun Ning

    2001-01-01

    Nonlinear diffusion equations, an important class of parabolic equations, come from a variety of diffusion phenomena which appear widely in nature. They are suggested as mathematical models of physical problems in many fields, such as filtration, phase transition, biochemistry and dynamics of biological groups. In many cases, the equations possess degeneracy or singularity. The appearance of degeneracy or singularity makes the study more involved and challenging. Many new ideas and methods have been developed to overcome the special difficulties caused by the degeneracy and singularity, which

  7. Diffusion in advanced materials

    CERN Document Server

    Murch, Graeme; Belova, Irina

    2014-01-01

    In the first chapter Prof. Kozubski and colleagues present atomisticsimulations of superstructure transformations of intermetallic nanolayers.In Chapter 2, Prof. Danielewski and colleagues discuss a formalism for themorphology of the diffusion zone in ternary alloys. In Chapter 3, ProfessorsSprengel and Koiwa discuss the classical contributions of Boltzmann andMatano for the analysis of concentration-dependent diffusion. This isfollowed by Chapter 4 by Professor Cserháti and colleagues on the use of Kirkendall porosity for fabricating hollow hemispheres. In Chapter 5,Professor Morton-Blake rep

  8. Ambipolar diffusion in plasma

    International Nuclear Information System (INIS)

    Silva, T.L. da.

    1987-01-01

    Is this thesis, a numerical method for the solution of the linear diffusion equation for a plasma containing two types of ions, with the possibility of charge exchange, has been developed. It has been shown that the decay time of the electron and ion densities is much smaller than that in a plasma containing only a single type of ion. A non-linear diffusion equation, which includes the effects of an external electric field varying linearly in time, to describe a slightly ionized plasma has also been developed. It has been verified that the decay of the electron density in the presence of such an electric field is very slow. (author)

  9. Modification of polycrystalline copper by proton irradiation

    International Nuclear Information System (INIS)

    Garcia S, F.; Cabral P, A.; Saniger B, J.M.; Banuelos, J.G.; Barragan V, A.

    1997-01-01

    Polished copper samples were irradiated with proton beams of 300 and 700 keV at room temperature and at -150 Centigrade. In this work the obtained results are reported when such copper irradiated samples are analysed with Sem, Tem, AFM. The Sem micrographs showed evident changes in surface of these copper samples, therefore an EDAX microanalysis was done for its characterization. additionally, the Tem micrographs showed heaps formation until 200 nm. Its electron diffraction spectra indicated that these heaps consist of a copper compound. Finally with AFM were observed changes in coloration of the irradiated sample surface, as well as changes in texture and rugosity of them. These results show in general that irradiation process with protons which is known as an innocuo process produces changes in the copper properties. (Author)

  10. Refining processes in the copper casting technology

    Directory of Open Access Journals (Sweden)

    S. Rzadkosz

    2015-01-01

    Full Text Available The paper presents the analysis of technology of copper and alloyed copper destined for power engineering casts. The casts quality was assessed based on microstructure, chemical content analysis and strength properties tests. Characteristic deoxidising (Logas, Cup and modifying (ODM2, Kupmod2 formulas were used for the copper where high electrical conductivity was required. Chosen examples of alloyed copper with varied Cr and Zr content were studied, and the optimal heat treatment parameters were tested for a chosen chromium copper content, based on the criterion of hardness and electrical conductivity tests. Searching for materials with high wear resistance, the influence of variable silicone content on the properties of CuNiSi alloy was researched.

  11. Activation of ADAM 12 protease by copper

    DEFF Research Database (Denmark)

    Loechel, F; Wewer, Ulla M.

    2001-01-01

    Conversion of latent proteases to the active form occurs by various mechanisms characteristic for different protease families. Here we report that the disintegrin metalloprotease ADAM 12-S is activated by Cu(II). Copper activation is distinct from the cysteine switch component of latency: elimina......Conversion of latent proteases to the active form occurs by various mechanisms characteristic for different protease families. Here we report that the disintegrin metalloprotease ADAM 12-S is activated by Cu(II). Copper activation is distinct from the cysteine switch component of latency......: elimination of the ADAM 12 cysteine switch by a point mutation in the propeptide had no effect on copper activation, whereas mutation of an unpaired cysteine residue in the catalytic domain resulted in a mutant form of ADAM 12-S that was insensitive to copper. This suggests a multi-step activation mechanism...... for ADAM 12 involving both furin cleavage and copper binding....

  12. Copper nitrate: a privileged reagent for organic synthesis.

    Science.gov (United States)

    Gao, Mingchun; Ye, Rongxuan; Shen, Weijia; Xu, Bin

    2018-04-18

    Copper has been explored as an ideal candidate for replacing noble metals in organic synthesis, especially for practical large scale preparation. Recent decades have witnessed the renaissance and improvement of copper-catalyzed and copper-mediated organic reactions. Copper nitrate is a common inorganic copper salt which has been proved to be a ubiquitous reactant in organic synthesis due to its commercial availability, stability, inexpensiveness and environmentally benign nature. Copper nitrate could be used as a nitration reagent, oxidant, catalyst or promoter, and Lewis acid as well. Remarkably, great attention has been devoted to the efficient transformation of copper nitrate into functionalized or complicated compounds through various reaction types including cyclization, C-H activation, difunctionalization, nitration, rearrangement and asymmetric synthesis with chiral ligands. Further modification of copper nitrate, such as solid-supported copper nitrate or copper nitrate complexes, extends its applications in organic synthesis. The present review highlights recent advances of copper nitrate in organic synthesis, along with the mechanisms.

  13. Rape prevention

    Science.gov (United States)

    Date rape - prevention; Sexual assault - prevention ... Centers for Disease Control and Prevention website. Sexual assault and abuse and STDs. In: 2015 sexually transmitted diseases treatment guidelines 2015. www.cdc.gov/std/tg2015/sexual- ...

  14. Dengue Prevention

    Science.gov (United States)

    ... Address What's this? Submit What's this? Submit Button Prevention Recommend on Facebook Tweet Share Compartir This photograph ... medications to treat a dengue infection. This makes prevention the most important step, and prevention means avoiding ...

  15. Synergistic Effect of L-Methionine and KI on Copper Corrosion Inhibition in HNO3 (1M

    Directory of Open Access Journals (Sweden)

    Amel SEDIK

    2014-05-01

    Full Text Available L-Methionine (L-Met efficiency as a non-toxic corrosion inhibitor for copper in 1M HNO3 has been studied by using electrochemical impedance spectroscopy (EIS and potentiodynamic polarization. Copper corrosion rate significant decrease was observed in the presence of L-Met at 10-4M. The Obtained Results from potentiodynamic polarization and impedance measurements are in good agreement. L-Methionine adsorption on copper surface follows Langmuir isotherm. L-Met free energy adsorption on copper (-30 KJ mol-1 reveals an inhibition strong physical adsorption on copper surface. In order to evaluate the L-Met effect, L-Met and iodide ion’synergistic effect was used to prevent copper corrosion in nitric acid. It was found that inhibitor efficiency (IE reached 98.27 % in 1M solution containing 10-4M L-Met and 10- 3 M KI. The synergistic effect was attributed to iodide ions adsorption on copper surface, which facilitated the L-Met adsorption and an inhibitive film formation.

  16. Anisotropy in "isotropic diffusion" measurements due to nongaussian diffusion

    DEFF Research Database (Denmark)

    Jespersen, Sune Nørhøj; Olesen, Jonas Lynge; Ianuş, Andrada

    2017-01-01

    Designing novel diffusion-weighted NMR and MRI pulse sequences aiming to probe tissue microstructure with techniques extending beyond the conventional Stejskal-Tanner family is currently of broad interest. One such technique, multidimensional diffusion MRI, has been recently proposed to afford...... model-free decomposition of diffusion signal kurtosis into terms originating from either ensemble variance of isotropic diffusivity or microscopic diffusion anisotropy. This ability rests on the assumption that diffusion can be described as a sum of multiple Gaussian compartments, but this is often...

  17. A study on biosorption of copper ions by fungal chitosan: an alternative to shrimp chitosan

    Directory of Open Access Journals (Sweden)

    Sanaz Behnam

    2015-02-01

    Full Text Available   Introduction : One of the main applications of chitosan is for heavy metals removal from waste waters. Industrially, chitosan is produced through deacetylation of chitin present in shellfish waste. Another source of chitosan is the cell wall of zygomycetes fungi with several advantages over shellfish wastes .   Materials and method s: Fungal chitosan purified from biomass of Mucor indicus and shrimp chitosan were applied and compared for removal of copper ions from aqueous solution. The effects of pH (3 to 5.5, copper ion concentration (5 to 52 mg l-1, the amount of chitosan (200 to 3000 mg l-1, adsorption time, temperature, and presence of other metal ions on the biosorption of Cu2+ were investigated .   Results : Maximum adsorption capacities for fungal and shrimp chitosans were 58.5 and 60.7 mg g-1, respectively. T he rate of copper adsorption by the fungal chitosan was significantly higher than that by the shrimp chitosan. Among p seudo-first order, pseudo-second order, intra-particle diffusion, and Elovich models, Ho’s pseudo-second order model was the best model for fitting the kinetic data. The adsorption capacity increased for both types of chitosans by increasing the solution pH. However, temperature and presence of other ions did not show significant effects on the biosorption capacity of copper. The isotherm data were very well described by Langmuir, Freundlich, and Redlich-Peterson models .   Discussion and conclusion : Both fungal and shrimp chitosans can effectively be used for removal of copper ions from aqueous solutions. Adsorption process for fungal chitosan is fast, while the process is slower for the shrimp chitosan. Therefore, from the kinetics point of view, the fungal chitosan is preferable compared with the shrimp chitosan . Key words: Biosorption, Copper, Fungal chitosan, Shrimp chitosan, Water treatment .

  18. Selective recovery of pure copper nanopowder from indium-tin-oxide etching wastewater by various wet chemical reduction process: Understanding their chemistry and comparisons of sustainable valorization processes.

    Science.gov (United States)

    Swain, Basudev; Mishra, Chinmayee; Hong, Hyun Seon; Cho, Sung-Soo

    2016-05-01

    Sustainable valorization processes for selective recovery of pure copper nanopowder from Indium-Tin-Oxide (ITO) etching wastewater by various wet chemical reduction processes, their chemistry has been investigated and compared. After the indium recovery by solvent extraction from ITO etching wastewater, the same is also an environmental challenge, needs to be treated before disposal. After the indium recovery, ITO etching wastewater contains 6.11kg/m(3) of copper and 1.35kg/m(3) of aluminum, pH of the solution is very low converging to 0 and contain a significant amount of chlorine in the media. In this study, pure copper nanopowder was recovered using various reducing reagents by wet chemical reduction and characterized. Different reducing agents like a metallic, an inorganic acid and an organic acid were used to understand reduction behavior of copper in the presence of aluminum in a strong chloride medium of the ITO etching wastewater. The effect of a polymer surfactant Polyvinylpyrrolidone (PVP), which was included to prevent aggregation, to provide dispersion stability and control the size of copper nanopowder was investigated and compared. The developed copper nanopowder recovery techniques are techno-economical feasible processes for commercial production of copper nanopowder in the range of 100-500nm size from the reported facilities through a one-pot synthesis. By all the process reported pure copper nanopowder can be recovered with>99% efficiency. After the copper recovery, copper concentration in the wastewater reduced to acceptable limit recommended by WHO for wastewater disposal. The process is not only beneficial for recycling of copper, but also helps to address environment challenged posed by ITO etching wastewater. From a complex wastewater, synthesis of pure copper nanopowder using various wet chemical reduction route and their comparison is the novelty of this recovery process. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Diffusion Based Photon Mapping

    DEFF Research Database (Denmark)

    Schjøth, Lars; Fogh Olsen, Ole; Sporring, Jon

    2007-01-01

    . To address this problem we introduce a novel photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way we preserve the important illumination features...

  20. Diffusion welding of metals

    International Nuclear Information System (INIS)

    Susei, Shuzo; Matsui, Shigetomo; Yamada, Takeshi

    1978-01-01

    Recently, the materials with high heat resistance, corrosion resistance or strength have been developed, and some of them cannot be welded by ordinary method. Thereupon solid phase joining method is noticed, the mechanism of which is entirely different from conventional fusion welding. Among various solid phase joining methods, diffusion welding has many features. In case of joining same material, the joint can be made chemically and mechanically same as the parent material, and in case of joining different materials, joining can be made without forming any harmful compound, and the embrittlement of joints can be avoided. Kawasaki Heavy Industries Corp. has carried out a series of research on the diffusion welding of various metals, but in this paper, the characteristics of the joints of same material and different materials in titanium alloys are reported. The diffusion welding apparatus used adopts radiation heating using a tungsten heater and a hydraulic cylinder for pressing. The atmosphere of welded materials is kept in vacuum. The tested materials were industrial pure titanium TB 35 and Ti-6 Al-4 V alloy. The weldability of these materials by diffusion welding was studied, and it was confirmed that the joint efficiency of 100% was able to be obtained. However, for the practical application, more studies are required. (Kako, I.)

  1. Diffusion in ceramics

    CERN Document Server

    Pelleg, Joshua

    2016-01-01

    This textbook provides an introduction to changes that occur in solids such as ceramics, mainly at high temperatures, which are diffusion controlled, as well as presenting research data. Such changes are related to the kinetics of various reactions such as precipitation, oxidation and phase transformations, but are also related to some mechanical changes, such as creep. The book is composed of two parts, beginning with a look at the basics of diffusion according to Fick's Laws. Solutions of Fick’s second law for constant D, diffusion in grain boundaries and dislocations are presented along with a look at the atomistic approach for the random motion of atoms. In the second part, the author discusses diffusion in several technologically important ceramics. The ceramics selected are monolithic single phase ones, including: A12O3, SiC, MgO, ZrO2 and Si3N4. Of these, three refer to oxide ceramics (alumina, magnesia and zirconia). Carbide based ceramics are represented by the technologically very important Si-ca...

  2. Diffusion in building wakes

    International Nuclear Information System (INIS)

    Ramsdell, J.V.

    1988-03-01

    Straight-line Gaussian models adequately describe atmospheric diffusion for many applications. They have been modified for use in estimating diffusion in building wakes by adding terms that include projected building area and by redefining the diffusion coefficients so that the coefficients have minimum values that are related to building dimensions. In a recent study, Ramsdell reviewed the building-wake dispersion models used by the Nuclear Regulatory Commission (NRC) in its control room habitability assessments. The review included comparison of model estimates of centerline concentrations with concentrations observed in experiments at seven nuclear reactors. In general, the models are conservative in that they tend to predict concentrations that are greater than those actually observed. However, the models show little skill in accounting for variations in the observed concentrations. Subsequently, the experimental data and multiples linear regression techniques have been used to develop a new building wake diffusion model. This paper describes the new building wake model and compares it with other models. 8 refs., 2 figs

  3. Osmosis and Diffusion

    Science.gov (United States)

    Sack, Jeff

    2005-01-01

    OsmoBeaker is a CD-ROM designed to enhance the learning of diffusion and osmosis by presenting interactive experimentation to the student. The software provides several computer simulations that take the student through different scenarios with cells, having different concentrations of solutes in them.

  4. Diffusion Based Photon Mapping

    DEFF Research Database (Denmark)

    Schjøth, Lars; Sporring, Jon; Fogh Olsen, Ole

    2008-01-01

    . To address this problem, we introduce a photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way, we preserve important illumination features, while...

  5. Plague Prevention

    Science.gov (United States)

    ... Healthcare Professionals Clinicians Public Health Officials Veterinarians Prevention History of Plague Resources FAQ Prevention Recommend on Facebook Tweet Share Compartir Reduce rodent habitat around your ...

  6. The copYAZ Operon Functions in Copper Efflux, Biofilm Formation, Genetic Transformation, and Stress Tolerance in Streptococcus mutans

    Science.gov (United States)

    Singh, Kamna; Senadheera, Dilani B.; Lévesque, Céline M.

    2015-01-01

    CopYAZ system in copper export and have further expanded knowledge on the importance of copper homeostasis and the CopYAZ system in modulating streptococcal physiology, including stress tolerance, membrane potential, genetic competence, and biofilm formation. IMPORTANCE S. mutans is best known for its role in the initiation and progression of human dental caries, one of the most common chronic diseases worldwide. S. mutans is also implicated in bacterial endocarditis, a life-threatening inflammation of the heart valve. The core virulence factors of S. mutans include its ability to produce and sustain acidic conditions and to form a polysaccharide-encased biofilm that provides protection against environmental insults. Here, we demonstrate that the addition of copper and/or deletion of copYAZ (the copper homeostasis system) have serious implications in modulating biofilm formation, stress tolerance, and genetic transformation in S. mutans. Manipulating the pathways affected by copper and the copYAZ system may help to develop potential therapeutics to prevent S. mutans infection in and beyond the oral cavity. PMID:26013484

  7. The copYAZ Operon Functions in Copper Efflux, Biofilm Formation, Genetic Transformation, and Stress Tolerance in Streptococcus mutans.

    Science.gov (United States)

    Singh, Kamna; Senadheera, Dilani B; Lévesque, Céline M; Cvitkovitch, Dennis G

    2015-08-01

    YAZ system in copper export and have further expanded knowledge on the importance of copper homeostasis and the CopYAZ system in modulating streptococcal physiology, including stress tolerance, membrane potential, genetic competence, and biofilm formation. S. mutans is best known for its role in the initiation and progression of human dental caries, one of the most common chronic diseases worldwide. S. mutans is also implicated in bacterial endocarditis, a life-threatening inflammation of the heart valve. The core virulence factors of S. mutans include its ability to produce and sustain acidic conditions and to form a polysaccharide-encased biofilm that provides protection against environmental insults. Here, we demonstrate that the addition of copper and/or deletion of copYAZ (the copper homeostasis system) have serious implications in modulating biofilm formation, stress tolerance, and genetic transformation in S. mutans. Manipulating the pathways affected by copper and the copYAZ system may help to develop potential therapeutics to prevent S. mutans infection in and beyond the oral cavity. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  8. Surface films and corrosion of copper

    International Nuclear Information System (INIS)

    Hilden, J.; Laitinen, T.; Maekelae, K.; Saario, T.; Bojinov, M.

    1999-03-01

    In Sweden and Finland the spent nuclear fuel is planned to be encapsulated in cast iron canisters that have an outer shield made of copper. The copper shield is responsible for the corrosion protection of the canister construction. General corrosion of the copper is not expected to be the limiting factor in the waste repository environment when estimating the life-time of the canister construction. However, different forms of localised corrosion, i.e. pitting, stress corrosion cracking, or environmentally assisted creep fracture may cause premature failure of the copper shield. Of the probable constituents in the groundwater, nitrites, chlorides, sulphides and carbonates have been suggested to promote localised corrosion of copper. The main assumption made in planning this research program is that the surface films forming on copper in the repository environment largely determine the susceptibility of copper to the different forms of localised corrosion. The availability of reactants, which also may become corrosion rate limiting, is investigated in several other research programs. This research program consists of a set of successive projects targeted at characterising the properties of surface films on copper in repository environment containing different detrimental anions. A further aim was to assess the significance of the anion-induced changes in the stability of the oxide films with regard to localised corrosion of copper. This report summarises the results from a series of investigations on properties of surface films forming on copper in water of pH = 8.9 at temperature of 80 deg C and pressure of 2 MPa. The main results gained so far in this research program are as follows: The surface films forming on copper in the thermodynamic stability region of monovalent copper at 80 deg C consist of a bulk part (about 1 mm thick) which is a good ionic and electronic conductor, and an outer, interfacial layer (0.001 - 0.005 mm thick) which shows p-type semiconductor

  9. Light diffusion in quenched disorder: role of step correlations.

    Science.gov (United States)

    Svensson, Tomas; Vynck, Kevin; Adolfsson, Erik; Farina, Andrea; Pifferi, Antonio; Wiersma, Diederik S

    2014-02-01

    We present a theoretical and experimental study of light transport in disordered media with strongly heterogeneous distribution of scatterers formed via nonscattering regions. Step correlations induced by quenched disorder are found to prevent diffusivity from diverging with increasing heterogeneity scale, contrary to expectations from annealed models. Spectral diffusivity is measured for a porous ceramic where nanopores act as scatterers and macropores render their distribution heterogeneous. Results agree well with Monte Carlo simulations and a proposed analytical model.

  10. The analysis of radon diffusion through the buildings materials

    International Nuclear Information System (INIS)

    Grujic, S.; Radukin-Kosanovic, A.; Bikit, I.; Mrdja, D.; Forkapic, S.

    2009-01-01

    Since people most of the time spent indoors it is of great importance to analyse the radon diffusion through different types of materials, in order to prevent the increase of its concentration in the interior of buildings. The paper examined six different types of materials used in construction, mainly in the insulating purposes, in order to determine the material, or a combination of appropriate type and thickness of material which have a smaller value of diffusion coefficient of radon. (author) [sr

  11. Industrial Tests to Modify Molten Copper Slag for Improvement of Copper Recovery

    Science.gov (United States)

    Guo, Zhengqi; Zhu, Deqing; Pan, Jian; Zhang, Feng; Yang, Congcong

    2018-04-01

    In this article, to improve the recovery of copper from copper slag by flotation process, industrial tests of the modification process involving addition of a composite additive into molten copper slag were conducted, and the modified slag was subjected to the flotation process to confirm the modification effect. The phase evolution of the slag in the modification process was revealed by thermodynamic calculations, x-ray diffraction, optical microscopy and scanning electron microscopy. The results show that more copper was transformed and enriched in copper sulfide phases. The magnetite content in the modified slag decreased, and that of "FeO" increased correspondingly, leading to a better fluidity of the molten slag, which improved the aggregation and growth of fine particles of the copper sulfide minerals. Closed-circuit flotation tests of the original and modified slags were conducted, and the results show that the copper recovery increased obviously from 69.15% to 73.38%, and the copper grade of concentrates was elevated slightly from 20.24% to 21.69%, further confirming that the industrial tests of the modification process were successful. Hence, the modification process has a bright future in industrial applications for enhancing the recovery of copper from the copper slag.

  12. Thermodynamic modelling of fast dopant diffusion in Si

    Science.gov (United States)

    Saltas, V.; Chroneos, A.; Vallianatos, F.

    2018-04-01

    In the present study, nickel and copper fast diffusion in silicon is investigated in the framework of the cBΩ thermodynamic model, which connects point defect parameters with the bulk elastic and expansion properties. All the calculated point defect thermodynamic properties (activation Gibbs free energy, activation enthalpy, activation entropy, and activation volume) exhibit temperature dependence due to the non-linear anharmonic behavior of the isothermal bulk modulus of Si. Calculated activation enthalpies (0.15-0.16 eV for Ni and 0.17-0.19 eV for Cu) are in agreement with the reported experimental results. Small values of calculated activation volumes for both dopants (˜4% of the mean atomic volume) are consistent with the interstitial diffusion of Ni and Cu in Si.

  13. Technical note 4. Corrosion of copper canister

    International Nuclear Information System (INIS)

    Szakalos, Peter; Seetharaman, Seshadri

    2012-06-01

    Objectives of the project: In this review assignment, SKB's treatment of copper corrosion processes or mechanisms in SR-Site shall be reviewed both for the anticipated oxic and anoxic repository environments. The reviewer(s) shall consider if corrosion and corrosion mechanisms of the copper canisters in different possible evolutionary repository environments have been properly described. The objectives of this initial review phase in the area of copper corrosion is to achieve a broad coverage of SR-Site and its supporting references and in particular identify the need for complementary information and clarifications to be delivered by SKB. Summary by the authors: It is expected that the inflow of ground water to the deposition holes and tunnels in the Forsmark repository will be very slow. Thus, it might take some few hundred years up to thousand years before the deposition holes are filled with ground water and it might take 6000 years or more before the bentonite buffer is fully water saturated and pressurized. The copper canisters will therefore meet to two completely different environments: 1. An initial period of several hundreds of years when copper is exposed to gaseous corrosion. 2. And then to aqueous corrosion. From a corrosion point of view the first 1000 years are the most critical for the copper canister since pure, or phosphorus alloyed copper, is not designed to cope with corrosion at elevated temperatures. The outer copper surface temperature is expected to reach 100 deg C within some decades after closure of the repository and then slowly cool down to around 50 deg C after 1000 years. The gaseous corrosion is treated in SKB's safety assessment as being only dependent on oxygen gas and thus easily estimated by an oxygen mass-balance calculation. This simple model has no scientific support since several corrosive trace gases, such as sulphurous and nitrous compounds, operates together with water molecules (moisture) and the corrosion product consists

  14. Grain boundary corrosion of copper canister material

    International Nuclear Information System (INIS)

    Fennell, P.A.H.; Graham, A.J.; Smart, N.R.; Sofield, C.J.

    2001-03-01

    The proposed design for a final repository for spent fuel and other long-lived residues in Sweden is based on the multi-barrier principle. The waste will be encapsulated in sealed cylindrical canisters, which will then be placed in granite bedrock and surrounded by compacted bentonite clay. The canister design is based on a thick cast inner container fitted inside a corrosion-resistant copper canister. During fabrication of the outer copper canisters there will be some unavoidable grain growth in the welded areas. As grains grow they will tend to concentrate impurities within the copper at the new grain boundaries. The work described in this report was undertaken to determine whether there is any possibility of enhanced corrosion at grain boundaries within the copper canister. The potential for grain boundary corrosion was investigated by exposing copper specimens, which had undergone different heat treatments and hence had different grain sizes, to aerated artificial bentonite-equilibrated groundwater with two concentrations of chloride, for increasing periods of time. The degree of grain boundary corrosion was determined by atomic force microscopy (AFM) and optical microscopy. AFM showed no increase in grain boundary 'ditching' for low chloride groundwater. In high chloride groundwater the surface was covered uniformly with a fine-grained oxide. No increases in oxide thickness were observed. No significant grain boundary attack was observed using optical microscopy either. The work suggests that in aerated artificial groundwaters containing chloride ions, grain boundary corrosion of copper is unlikely to adversely affect SKB's copper canisters

  15. Pilot plant for biohidrometallurgical production of copper

    Directory of Open Access Journals (Sweden)

    Conić Vesna T.

    2009-01-01

    Full Text Available In this work, technical and technological characteristics of pilot plant for biohydrometallurgical production of copper financed by Ministry of Science and Environment Protection of Serbia, in the frame of capital providing for scientific research for the period 2006-2008 is presented. Presented within this project is the contribution and capability of the Institute for Mining and Metallurgy Bor to carry out the Fp6 IP project: 'Biotechnology for Metal Bearing Materials in Europe (BioMinE'. In the pilot plant, processes such as: microbiological leaching, pressures oxidation, chemical purification of solutions, solvent extraction and electrowining of copper were carried out. Bioleaching can treat complex copper concentrates which are either unacceptable to smelting or attract high penalties. Some of the elements penalized in smelting (for example zinc are dissolved in the bioleach process and can be recovered for sale. This may often allow an increased recovery of a few percent in the production of the copper concentrate. Bioleaching can be used in either small or large cathodic copper production from copper concentrate. Bioleaching uses conventional upstream and downstream process technology and the unit operation itself has been proven in the gold industry. For these reasons, this work describes the pilot plant for biotechnological production of copper from RTB Bor resources.

  16. Thermal enrichment and speciation of copper in rice husk ashes.

    Science.gov (United States)

    Wei, Yu-Ling; Hu, Ming-Jan; Peng, Yen-Hsun

    2010-12-15

    Copper(II) was considerably enriched in the residual ash via thermal treatment of copper-sorbed rice husk at 700-1100°C for 2h, and the copper speciation was quantitatively determined with X-ray absorption spectroscopy. After the thermal process, the resulting ash only represents by weight 18.7-26.4% of the pre-heated samples. Copper content in the ashes is >7% which is far above the required minimum copper content in copper ores for the copper smelting sector, 0.5%. Crystalline SiO(2) is observed only in the ash generated at 1100°C, with more copper in this ash being available for leaching in acidic solution. It is suggested that this is due to the considerable dissimilarity in crystalline structure between copper compounds and crystalline SiO(2). No chemical reaction between copper and SiO(2) is observed in any ash. In fact, we suggest that the SiO(2) crystalline phase repels copper during the thermal process; this would make it easy to extract copper from the ashes. For copper speciation in the ashes, CuO merely represents 0-12% of the total copper, while Cu(2)O and Cu(0) represent 34-42% and 46-63%, respectively. The lower copper oxidation state would be beneficial for the copper smelting process due to less usage of coke. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. Effects of Copper Exchange Levels on Complexation of Ammonia in ...

    African Journals Online (AJOL)

    NJD

    At low copper exchange levels (<5 copper atoms per unit cell), the major complex is [Cu(Ozeo)2(NH3)2]2+ and ... amount of ammonia. KEYWORDS. Cation exchange, catalysis, copper, complexation, copper ammines. 1. .... at a 4 kHz MAS spinning rate on a Bruker AC 300 NMR spectro- meter (Fitchburg, MA, USA) at 7.05 ...

  18. Effect of aging on copper nanoparticles synthesized by pulsed laser ...

    Indian Academy of Sciences (India)

    Administrator

    2009-06-23

    Jun 23, 2009 ... using 1064 nm wavelength of pulsed Nd : YAG laser. The present paper deals with synthesis of copper and copper oxide nanoparticles by pulsed laser ablation in water and effect of aging on these nanoparticles. 2. Experimental. To produce the copper nanoparticles, a piece of copper metal (99⋅99% ...

  19. The various faces of copper in laboratory animals

    NARCIS (Netherlands)

    Wolf, Ingeborg Désirée de

    2001-01-01

    All research described in this thesis focuses on the role of copper in various biochemical processes. It appears that copper has various faces in laboratory animals. On the one hand, copper is an essential trace element, which implicates that a certain requirement for copper exists. On the other

  20. Inactivation of bacterial and viral biothreat agents on metallic copper surfaces.

    Science.gov (United States)

    Bleichert, Pauline; Espírito Santo, Christophe; Hanczaruk, Matthias; Meyer, Hermann; Grass, Gregor

    2014-12-01

    In recent years several studies in laboratory settings and in hospital environments have demonstrated that surfaces of massive metallic copper have intrinsic antibacterial and antiviral properties. Microbes are rapidly inactivated by a quick, sharp shock known as contact killing. The underlying mechanism is not yet fully understood; however, in this process the cytoplasmic membrane is severely damaged. Pathogenic bacterial and viral high-consequence species able to evade the host immune system are among the most serious lethal microbial challenges to human health. Here, we investigated contact-killing mediated by copper surfaces of Gram-negative bacteria (Brucella melitensis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis tularensis and Yersinia pestis) and of Gram-positive endospore-forming Bacillus anthracis. Additionally, we also tested inactivation of monkeypox virus and vaccinia virus on copper. This group of pathogens comprises biothreat species (or their close relatives) classified by the Center for Disease and Control and Prevention (CDC) as microbial select agents posing severe threats to public health and having the potential to be deliberately released. All agents were rapidly inactivated on copper between 30 s and 5 min with the exception of B. anthracis endospores. For vegetative bacterial cells prolonged contact to metallic copper resulted in the destruction of cell structure.

  1. Antibacterial activity of agricultural waste derived wollastonite doped with copper for bone tissue engineering.

    Science.gov (United States)

    Azeena, S; Subhapradha, N; Selvamurugan, N; Narayan, S; Srinivasan, N; Murugesan, R; Chung, T W; Moorthi, A

    2017-02-01

    Bioactive ceramic materials with metal ions generation brought great attention in the class of biomaterials development and widely employed as a filler material for bone tissue regeneration. The present study aimed to fabricate calcium silicate based ceramic material doped with copper metal particles by sol-gel method. Rice straw of agricultural waste was utilized as a source material to synthesize wollastonite, then wollastonite was doped with copper to fabricate copper doped wollastonite (Cu-Ws) particles. The synthesized materials were subjected to physio-chemical characterization by TEM, DLS, FTIR, XRD and DSC analysis. It was found that the sizes of the WS particles was around 900nm, while adding copper the size was increased upto 1184nm and the addition of copper to the material sharpening the peak. The release of Cu ions was estimated by ICP analysis. The anti-bacterial potentiality of the particles suggested that better microbial growth inhibition against E. coli (Gram negative) and S. aureus (Gram positive) strains from ATCC, in which the growth inhibition was more significant against S. aureus. The biocompatibility in mouse Mesenchymal Stem cells (mMSC) showed the non-toxic effect up to 0.05mg/ml concentration while the increase in concentration was found to be toxic to the cells. So the particles may have better potential application with the challenging prevention of post implantation infection in the field of bone tissue engineering (BTE). Copyright © 2016. Published by Elsevier B.V.

  2. Toxicity of copper sulfate and rotenone to Chinese mystery snail (Bellamya chinensis)

    Science.gov (United States)

    Haak, Danielle M.; Stephen, Bruce J.; Kill, Robert A.; Smeenk, Nicholas A.; Allen, Craig R.; Pope, Kevin L.

    2014-01-01

    The Chinese mystery snail (Bellamya chinensis) is a freshwater snail native to Southeast Asia, Japan, and Russia and is currently classified as an invasive species in at least 27 states in the USA. The species tolerates a wide range of environmental conditions, making management of established populations difficult. We tested the efficacy of two traditional chemical treatments, rotenone and copper sulfate, on the elimination of adult Chinese mystery snails in laboratory experiments. All snails (N=50) survived 72-hour exposure to rotenone-treated lake water, and 96% (N=25) survived 72-hour exposure to pre-determined rotenone concentrations of 0.25, 2.5, and 25.0 mg/L. All snails (N=10) survived exposure to 1.25 mg/L copper sulfate solution, 90% (N=10) survived exposure to 2.50 mg/L copper sulfate solution, and 80% (N=5) survived exposure to 5.0 mg/L copper sulfate solution. Neither rotenone nor copper sulfate effectively killed adult Chinese mystery snails in laboratory experiments, most likely due to their relatively large size, thick shell, and operculum. Therefore, it appears that populations will be very difficult to control once established, and management should focus on preventing additional spread or introductions of this species.

  3. Effects of copper on early developmental stages of Lessonia nigrescens Bory (Phaeophyceae)

    International Nuclear Information System (INIS)

    Contreras, Loretto; Medina, Matias H.; Andrade, Santiago; Oppliger, Valeria; Correa, Juan A.

    2007-01-01

    Copper effects on the early developmental gametophytic and sporophytic stages of the kelp Lessonia nigrescens were tested in gradients of increasing concentrations of ASV-labile copper. The results demonstrated a high sensitivity to copper of all life-history stages of the alga, where even the lowest tested concentration affected spore release as well as their subsequent settlement. More significant, concentrations higher than 7.87 μg L -1 totally interrupted the development of the spores after they settle. This effect led to a failure in the formation of male and female gametophytes and, as a consequence, to a complete disruption of the normal life cycle of the kelp. Thus, we suggest that the absence of L. nigrescens from copper-enriched environments results from the high sensitivity of its early life cycle stages, which limits growth and maturation of the gametophytic microscopic phase and, as a consequence, prevents development of the macroscopic sporophytic phase. - Early developmental stages of Lessonia nigrescens are highly sensitive to copper

  4. Study of the influence of surface-active substances on the initial stage of copper electrodeposition

    Directory of Open Access Journals (Sweden)

    Amantay Dalbanbay

    2017-12-01

    Full Text Available In this research, the effect of surface-active substances (CMC and DFP on the electrolysis of copper by cyclic voltammetry (CVA and chronoamperometric methods was studied. The working electrode was a glassy carbon electrode. Studies show that in the acid solution of copper sulfate (10-2 M CuSO4 + 0.5 M H2SO4, the three-dimensional electrochemical deposition of copper occurs by the mechanism of instantaneous nucleation. The added surface active substances affect the dischargeionization process, the standard electroreduction potential is shifted to the negative side. The added DFP reduces the cathodic peak current, and the addition of CMC results in its increase. At the deposition potentials corresponding to the regions up to the CVA peak current (here, still, the mixed electrodeposition kinetics, the number of nuclei formed is greater for a pure solution, but at current decay potentials, where the diffusion regime takes place, the nuclei population density (NPD is higher for solutions with surfactants. The most powerful effect here is caused by the addition of DFP. In the case of mixed additives, the NPD values are close to those of the CMC, obviously indicating the preferential adsorption of CMC, whereas the DFP as complexes with copper ions is closer to the near-electrode region.

  5. Copper accumulation by stickleback nests containing spiggin.

    Science.gov (United States)

    Pinho, G L L; Martins, C M G; Barber, I

    2016-07-01

    The three-spined stickleback is a ubiquitous fish of marine, brackish and freshwater ecosystems across the Northern hemisphere that presents intermediate sensitivity to copper. Male sticklebacks display a range of elaborate reproductive behaviours that include nest construction. To build the nests, each male binds nesting material together using an endogenous glycoprotein nesting glue, known as 'spiggin'. Spiggin is a cysteine-rich protein and, therefore, potentially binds heavy metals present in the environment. The aim of this study was to investigate the capacity of stickleback nests to accumulate copper from environmental sources. Newly built nests, constructed by male fish from polyester threads in laboratory aquaria, were immersed in copper solutions ranging in concentration from 21.1-626.6 μg Cu L(-1). Bundles of polyester threads from aquaria without male fish were also immersed in the same copper solutions. After immersion, nests presented higher amounts of copper than the thread bundles, indicating a higher capacity of nests to bind this metal. A significant, positive correlation between the concentration of copper in the exposure solution and in the exposed nests was identified, but there was no such relationship for thread bundles. Since both spiggin synthesis and male courtship behaviour are under the control of circulating androgens, we predicted that males with high courtship scores would produce and secrete high levels of the spiggin protein. In the present study, nests built by high courtship score males accumulated more copper than those built by low courtship score males. Considering the potential of spiggin to bind metals, the positive relationship between fish courtship and spiggin secretion seems to explain the higher amount of copper on the nests from the fish showing high behaviour scores. Further work is now needed to determine the consequences of the copper binding potential of spiggin in stickleback nests for the health and survival of

  6. Diffusing diffusivity: a new derivation and comparison with simulations

    Indian Academy of Sciences (India)

    Rohit Jain

    Rohit Jain and K L Sebastian simulations of a tracer particle diffusing in crowded environment of randomly moving barriers,9 for dif- fusion in a 2D complex plasma10 and for activated motion in live cells.11 Recently, we12 gave a model of “diffusing diffusivity” where diffusion coefficient is modeled as a Lévy flight process ...

  7. Copper homeostasis in Mycobacterium tuberculosis.

    Science.gov (United States)

    Shi, Xiaoshan; Darwin, K Heran

    2015-06-01

    Copper (Cu) is a trace element essential for the growth and development of almost all organisms, including bacteria. However, Cu overload in most systems is toxic. Studies show Cu accumulates in macrophage phagosomes infected with bacteria, suggesting Cu provides an innate immune mechanism to combat invading pathogens. To counteract the host-supplied Cu, increasing evidence suggests that bacteria have evolved Cu resistance mechanisms to facilitate their pathogenesis. In particular, Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, has evolved multiple pathways to respond to Cu. Here, we summarize what is currently known about Cu homeostasis in Mtb and discuss potential sources of Cu encountered by this and other pathogens in a mammalian host.

  8. Auger electron spectroscopy study of initial stages of oxidation in a copper - 19.6-atomic-percent-aluminum alloy

    Science.gov (United States)

    Ferrante, J.

    1973-01-01

    Auger electron spectroscopy was used to examine the initial stages of oxidation of a polycrystalline copper - 19.6 a/o-aluminum alloy. The growth of the 55-eV aluminum oxide peak and the decay of the 59-, 62-, and 937-eV copper peaks were examined as functions of temperature, exposure, and pressure. Pressures ranged from 1x10 to the minus 7th power to 0.0005 torr of O2. Temperatures ranged from room temperature to 700 C. A completely aluminum oxide surface layer was obtained in all cases. Complete disappearance of the underlying 937-eV copper peak was obtained by heating at 700 C in O2 at 0.0005 torr for 1 hr. Temperature studies indicated that thermally activated diffusion was important to the oxidation studies. The initial stages of oxidation followed a logarithmic growth curve.

  9. A reliable and reproducible method for the lipase assay in an AOT/isooctane reversed micellar system: modification of the copper-soap colorimetric method.

    Science.gov (United States)

    Kwon, Chang Woo; Park, Kyung-Min; Choi, Seung Jun; Chang, Pahn-Shick

    2015-09-01

    The copper-soap method, which is based on the absorbance of a fatty acid-copper complex at 715 nm, is a widely used colorimetric assay to determine the lipase activity in reversed micellar system. However, the absorbance of the bis(2-ethylhexyl) sodium sulfosuccinate (AOT)-copper complex prevents the use of an AOT/isooctane reversed micellar system. An extraction step was added to the original procedure to remove AOT and eliminate interference from the AOT-copper complex. Among the solvents tested, acetonitrile was determined to be the most suitable because it allows for the generation of a reproducible calibration curve with oleic acid that is independent of the AOT concentrations. Based on the validation data, the modified method, which does not experience interference from the AOT-copper complex, could be a useful method with enhanced accuracy and reproducibility for the lipase assay. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Inducible plasmid-mediated copper resistance in Escherichia coli.

    Science.gov (United States)

    Rouch, D; Camakaris, J; Lee, B T; Luke, R K

    1985-04-01

    The copper resistance in Escherichia coli determined by plasmid pRJ1004 is inducible. The level of resistance is proportional to the inducing dose of copper. The level of copper resistance in induced and uninduced cells changes with the growth phase of the culture. Induced resistant cells accumulate less copper than uninduced cells, so that reduced accumulation may be the mechanism of resistance. We propose that the inducible plasmid-coded copper resistance interacts with the normal metabolism of the cell to protect against toxic levels of copper while allowing continued operation of copper-dependent functions.

  11. Copper delivery to chloroplast proteins and its regulation

    Directory of Open Access Journals (Sweden)

    Guadalupe eAguirre

    2016-01-01

    Full Text Available Copper is required for photosynthesis in chloroplasts of plants because it is a cofactor of plastocyanin, an essential electron carrier in the thylakoid lumen. Other chloroplast copper proteins are copper/zinc superoxide dismutase and polyphenol oxidase,¬ but these proteins seem to be dispensable under conditions of low copper supply when transcripts for these proteins undergo microRNA-mediated down regulation. Two ATP-driven copper transporters function in tandem to deliver copper to chloroplast compartments. This review seeks to summarize the mechanisms of copper delivery to chloroplast proteins and its regulation. We also delineate some of the unanswered questions that still remain in this field.

  12. Copper doped borate dosimeters revisited

    Energy Technology Data Exchange (ETDEWEB)

    Alajerami, Y.S.M. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Department of Medical Radiography, Al-Azhar University, Gaza Strip, Palestine (Country Unknown); Hashim, S., E-mail: suhairul@utm.my [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Oncology Treatment Centre, Sultan Ismail Hospital, 81100 Johor Bahru (Malaysia); Ghoshal, S.K. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Bradley, D.A. [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Mhareb, M. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Saleh, M.A. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); National Atomic Energy Commission (NATEC), Sana' a (Yemen)

    2014-11-15

    We render a panoramic overview on copper (Cu) doped borate dosimeters. Preparing a dosimeter by mixing specific materials with precise weights and methods is a never-ending quest. The recommended composition is highly decisive for accurate estimation of the absorbed dose, prediction of the biological outcome, determination of the treatment dose for radiation therapy and facilitation of personal monitoring. Based on these principles, the proposed dosimeter must cover a series of dosimetric properties to realize the exact results and assessment. The doped borate dosimeters indeed demonstrate attractive thermoluminescence (TL) features. Several dedicated efforts are attempted to improve the luminescence properties by doping various transition metals or rare-earth elements. The Cu ion being one of the preferred activators shows excellent TL properties as revealed via detail comparison with other dosimeters. Two oxide states of Cu (Cu{sup +} and Cu{sup ++}) with reasonable atomic number allow easy interaction with boron network. Interestingly, the intrinsic luminescent centers of borate lattice are in cross linked with that of Cu{sup +} ions. Thus, the activation of borate dosimeter with Cu ions for the enhancement of the TL sensitivity is recognized. These dosimeters reveal similar glow curves as the standard TLD-100 (LiF:Mg,Ti) one irrespective of the use of modifiers and synthesis techniques. They display high sensitivity, low fading, dose response linearity over wide range and practical minimum detectable dose. Furthermore, the effective atomic number being the most beneficial aspect (equivalent to that of human tissue) of borate dosimeters do not show any change due to Cu ion activations. The past development, major challenges, excitement, applications, recent progress and the future promises of Cu doped borate TL dosimeters are highlighted. - Highlights: • The manuscript gives a panoramic overview on copper doped borate dosimeters. • Cu ions activated

  13. Copper doped borate dosimeters revisited

    International Nuclear Information System (INIS)

    Alajerami, Y.S.M.; Hashim, S.; Ghoshal, S.K.; Bradley, D.A.; Mhareb, M.; Saleh, M.A.

    2014-01-01

    We render a panoramic overview on copper (Cu) doped borate dosimeters. Preparing a dosimeter by mixing specific materials with precise weights and methods is a never-ending quest. The recommended composition is highly decisive for accurate estimation of the absorbed dose, prediction of the biological outcome, determination of the treatment dose for radiation therapy and facilitation of personal monitoring. Based on these principles, the proposed dosimeter must cover a series of dosimetric properties to realize the exact results and assessment. The doped borate dosimeters indeed demonstrate attractive thermoluminescence (TL) features. Several dedicated efforts are attempted to improve the luminescence properties by doping various transition metals or rare-earth elements. The Cu ion being one of the preferred activators shows excellent TL properties as revealed via detail comparison with other dosimeters. Two oxide states of Cu (Cu + and Cu ++ ) with reasonable atomic number allow easy interaction with boron network. Interestingly, the intrinsic luminescent centers of borate lattice are in cross linked with that of Cu + ions. Thus, the activation of borate dosimeter with Cu ions for the enhancement of the TL sensitivity is recognized. These dosimeters reveal similar glow curves as the standard TLD-100 (LiF:Mg,Ti) one irrespective of the use of modifiers and synthesis techniques. They display high sensitivity, low fading, dose response linearity over wide range and practical minimum detectable dose. Furthermore, the effective atomic number being the most beneficial aspect (equivalent to that of human tissue) of borate dosimeters do not show any change due to Cu ion activations. The past development, major challenges, excitement, applications, recent progress and the future promises of Cu doped borate TL dosimeters are highlighted. - Highlights: • The manuscript gives a panoramic overview on copper doped borate dosimeters. • Cu ions activated technique in borate

  14. Inhibition of pathogenic bacterial growth on excision wound by green synthesized copper oxide nanoparticles leads to accelerated wound healing activity in Wistar Albino rats.

    Science.gov (United States)

    Sankar, Renu; Baskaran, Athmanathan; Shivashangari, Kanchi Subramanian; Ravikumar, Vilwanathan

    2015-07-01

    An impaired wound healing is one of the major health related problem in diabetic and non-diabetic patients around the globe. The pathogenic bacteria play a predominant role in delayed wound healing, owing to interaction in the wound area. In our previous work we developed green chemistry mediated copper oxide nanoparticles using Ficus religiosa leaf extract. In the present study we make an attempt to evaluate the anti-bacterial, and wound healing activity of green synthesized copper oxide nanoparticles in male Wistar Albino rats. The agar well diffusion assay revealed copper oxide nanoparticles have substantial inhibition activity against human pathogenic strains such as Klebsiella pneumoniae, Shigella dysenteriae, Staphylococcus aureus, Salmonella typhimurium and Escherichia coli, which were responsible for delayed wound healing process. Furthermore, the analyses results of wound closure, histopathology and protein profiling confirmed that the F. religiosa leaf extract tailored copper oxide nanoparticles have enhanced wound healing activity in Wistar Albino rats.

  15. Structural state and geometric representation of a laser-welded joint between corrosion-resistant steel and titanium alloy with copper insert

    Science.gov (United States)

    Michurov, N. S.; Veretennikova, I. A.; Pugacheva, N. B.; Smirnova, E. O.

    2017-12-01

    The paper shows a characteristic structure of a welded joint between titanium alloy and corrosion-resistant steel, with a copper insert, produced by carbon dioxide laser welding. In the formation of the joint, the materials being welded are dissolved and mixed in the copper interlayer. The material of the welded joint is an oversaturated solid solution of Fe, Ni, Cr and Ti in the copper lattice with distributed TiFe, Ti(Fe, Cr)2 and CuTi2 intermetallic particles. A 10-150 µm thick diffusion zone with an altered chemical composition appears at the boundary with the steel, and a 50- 100 µm thick zone of the kind is formed at the boundary with the titanium alloy. The phase composition is determined and recrystallization maps at the boundaries of the welded joint are obtained. A geometric representation of a laser welded joint between titanium alloy and corrosion-resistant steel with a copper insert is constructed.

  16. Mycobacterium tuberculosis copper-regulated protein SocB is an intrinsically disordered protein that folds upon interaction with a synthetic phospholipid bilayer.

    Science.gov (United States)

    Nowicka, Urszula; Hoffman, Morgan; Randles, Leah; Shi, Xiaoshan; Khavrutskii, Lyuba; Stefanisko, Karen; Tarasova, Nadya I; Darwin, K Heran; Walters, Kylie J

    2016-02-01

    Multiple genes in Mycobacterium tuberculosis (Mtb) are regulated by copper including socAB (small orf induced by copper A and B), which is induced by copper and repressed by RicR (regulated in copper repressor). socA and socB encode hypothetical proteins of 61 and 54 amino acids, respectively. Here, we use biophysical and computational methods to evaluate the SocB structure. We find that SocB lacks evidence for secondary structure, with no thermal cooperative unfolding event, according to circular dichroism measurements. 2D NMR spectra similarly exhibit hallmarks of a disordered structural state, which is also supported by analyzing SocB diffusion. Altogether, these findings suggest that by itself SocB is intrinsically disordered. Interestingly, SocB interacts with a synthetic phospholipid bilayer and becomes helical, which suggests that it may be membrane-associated. © 2015 Wiley Periodicals, Inc.

  17. Transport coefficients in copper vapor arc plasmas

    International Nuclear Information System (INIS)

    Rahal, A.M.; Rahhaoui, B.; Vacquie, S.

    1985-01-01

    The presence of copper vapors modifies the properties of arc discharges. The paper deals with a region not investigated earlier, where in the core of the positive column of very short or high current arcs there is a high copper concentration. At these values the relative losses take a greater part in the energy balance. Using the charged-charged collision integrals, the transport coefficients (axial temperature, thermal and electric conductivity, viscosity) of the plasma with higher copper vapor concentration are calculated as the function of the arc current intensity. (D.Gy.)

  18. Study of laser welding of copper sheets

    OpenAIRE

    A. Klimpel; A. Rzeźnikiewicz; Ł. Janik

    2007-01-01

    Purpose: Purpose of this research is to study laser autogenous welding process of short seam beads and filletwelds of lap joints of oxygen-free copper sheets 1.0 [mm] thick. On the bases of results of quality assessment itwas proved that high power diode laser (HPDL) welded lap joints of copper sheet provide mechanical propertieson the level of parent material.Design/methodology/approach: Short seam beads and fillet welds of lap joints of oxygen-free copper sheets 1,0[mm] thick were tested, t...

  19. Graphene-protected copper and silver plasmonics

    DEFF Research Database (Denmark)

    Kravets, V. G.; Jalil, R.; Kim, Y. J.

    2014-01-01

    suitable for plasmonic applications. To this end, there has been a continuous search for alternative plasmonic materials that are also compatible with complementary metal oxide semiconductor technology. Here we show that copper and silver protected by graphene are viable candidates. Copper films covered...... with one to a few graphene layers show excellent plasmonic characteristics. They can be used to fabricate plasmonic devices and survive for at least a year, even in wet and corroding conditions. As a proof of concept, we use the graphene-protected copper to demonstrate dielectric loaded plasmonic...... waveguides and test sensitivity of surface plasmon resonances. Our results are likely to initiate wide use of graphene-protected plasmonics....

  20. Cementation of silver ions on metallic copper

    International Nuclear Information System (INIS)

    Jaskula, M.

    2009-01-01

    The silver cementation on metallic copper was investigated in the presence or absence of oxygen. The influence of sulphuric acid and copper sulphate concentration on the silver cement morphology was studied in details, and results were linked with the previously determined kinetics data of the process. The morpgology of silver depopsit was found to be independent of the prosence of oxygen in the system in as well as the sulphuric acide concentration. Contrary, the concentration of copper sulphate strongly influenced the morphology of silver deposite. Two-stage mechanism of cementation was proposed. (authors).

  1. A new model integrating short- and long-term aging of copper added to soils.

    Directory of Open Access Journals (Sweden)

    Saiqi Zeng

    Full Text Available Aging refers to the processes by which the bioavailability/toxicity, isotopic exchangeability, and extractability of metals added to soils decline overtime. We studied the characteristics of the aging process in copper (Cu added to soils and the factors that affect this process. Then we developed a semi-mechanistic model to predict the lability of Cu during the aging process with descriptions of the diffusion process using complementary error function. In the previous studies, two semi-mechanistic models to separately predict short-term and long-term aging of Cu added to soils were developed with individual descriptions of the diffusion process. In the short-term model, the diffusion process was linearly related to the square root of incubation time (t1/2, and in the long-term model, the diffusion process was linearly related to the natural logarithm of incubation time (lnt. Both models could predict short-term or long-term aging processes separately, but could not predict the short- and long-term aging processes by one model. By analyzing and combining the two models, we found that the short- and long-term behaviors of the diffusion process could be described adequately using the complementary error function. The effect of temperature on the diffusion process was obtained in this model as well. The model can predict the aging process continuously based on four factors-soil pH, incubation time, soil organic matter content and temperature.

  2. Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierrae from California

    Science.gov (United States)

    Purvis, O.W.; Bennett, J.P.; Spratt, J.

    2011-01-01

    An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its colour was due to copper accumulation in the cortex. The present study addressed the hypothesis that the green colour in similar material we sampled from Warren Canyon in 2008, is caused by copper localization in the thallus. Optical microscopy and electron microprobe analysis of specimens of L. sierrae confirmed that copper localization took place in the cortex. Elemental analyses of L. sierrae and three other species from the same localities showed high enrichments of copper and selenium, suggesting that copper selenates or selenites might occur in these lichens and be responsible for the unusual colour. Copyright ?? 2011 British Lichen Society.

  3. Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierra from California

    Science.gov (United States)

    Purvis, O.W.; Bennett, J.P.; Spratt, J.

    2011-01-01

    An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its colour was due to copper accumulation in the cortex. The present study addressed the hypothesis that the green colour in similar material we sampled from Warren Canyon in 2008, is caused by copper localization in the thallus. Optical microscopy and electron microprobe analysis of specimens of L. sierrae confirmed that copper localization took place in the cortex. Elemental analyses of L. sierrae and three other species from the same localities showed high enrichments of copper and selenium, suggesting that copper selenates or selenites might occur in these lichens and be responsible for the unusual colour.

  4. Effects of organic matters coming from Chinese tea on soluble copper release from copper teapot

    International Nuclear Information System (INIS)

    Ni Lixiao; Li Shiyin

    2008-01-01

    The morphology and elemental composition of the corrosion products of copper teapot's inner-surface were characterized by the scanning electron microscopy and energy dispersive X-ray surface analysis (SEM/EDS), X-ray powder diffraction (XRD) and X-ray photon spectroscopy (XPS) analysis. It was revealed that Cu, Fe, Ca, P, Si and Al were the main elements of corrosion by-products, and the α-SiO 2 , Cu 2 O and CaCO 3 as the main mineral components on the inner-surface of copper teapot. The effects of organic matters coming from Chinese tea on soluble copper release from copper teapots in tap water were also investigated. The results showed that the doses of organic matter (as TOC), temperate and stagnation time have significant effects on the concentration of soluble copper released from copper teapots in tap water

  5. Robust tensor estimation in diffusion tensor imaging

    Science.gov (United States)

    Maximov, Ivan I.; Grinberg, Farida; Jon Shah, N.

    2011-12-01

    The signal response measured in diffusion tensor imaging is subject to detrimental influences caused by noise. Noise fields arise due to various contributions such as thermal and physiological noise and sources related to the hardware imperfection. As a result, diffusion tensors estimated by different linear and non-linear least squares methods in absence of a proper noise correction tend to be substantially corrupted. In this work, we propose an advanced tensor estimation approach based on the least median squares method of the robust statistics. Both constrained and non-constrained versions of the method are considered. The performance of the developed algorithm is compared to that of the conventional least squares method and of the alternative robust methods proposed in the literature. Two examples of simulated diffusion attenuations and experimental in vivo diffusion data sets were used as a basis for comparison. The robust algorithms were shown to be advantageous compared to the least squares method in the cases where elimination of the outliers is desirable. Additionally, the constraints were applied in order to prevent generation of the non-positive definite tensors and reduce related artefacts in the maps of fractional anisotropy. The developed method can potentially be exploited also by other MR techniques where a robust regression or outlier localisation is required.

  6. The Effective Electrolytic Recovery of Dilute Copper from Industrial Wastewater

    Directory of Open Access Journals (Sweden)

    Teng-Chien Chen

    2013-01-01

    Full Text Available Electroplating copper industry was discharged huge amount wastewater and cause serious environmental and health damage in Taiwan. This research applied electrical copper recovery system to recover copper metal. In this work, electrotreatment of a industrial copper wastewater ([Cu] = 30000 mg L−1 was studied with titanium net coated with a thin layer of RuO2/IrO2 (DSA reactor. The optimal result for simulated copper solution was 99.9% copper recovery efficiency in current density 0.585 A/dm2 and no iron ion. Due to high concentration of iron and chloride ions in real industrial wastewater, the copper recovery efficiency was down to 60%. Although, the copper recovery efficiency was not high as simulated copper solution, high environmental economic value was included in the technology. The possibility of pretreating the wastewater with iron is the necessary step, before the electrical recovery copper system.

  7. Fractal model of anomalous diffusion.

    Science.gov (United States)

    Gmachowski, Lech

    2015-12-01

    An equation of motion is derived from fractal analysis of the Brownian particle trajectory in which the asymptotic fractal dimension of the trajectory has a required value. The formula makes it possible to calculate the time dependence of the mean square displacement for both short and long periods when the molecule diffuses anomalously. The anomalous diffusion which occurs after long periods is characterized by two variables, the transport coefficient and the anomalous diffusion exponent. An explicit formula is derived for the transport coefficient, which is related to the diffusion constant, as dependent on the Brownian step time, and the anomalous diffusion exponent. The model makes it possible to deduce anomalous diffusion properties from experimental data obtained even for short time periods and to estimate the transport coefficient in systems for which the diffusion behavior has been investigated. The results were confirmed for both sub and super-diffusion.

  8. Urban diffusion problems

    International Nuclear Information System (INIS)

    Hanna, S.R.

    1976-01-01

    It is hoped that urban diffusion models of air pollutants can eventually confidently be used to make major decisions, such as in planning the layout of a new industrial park, determining the effects of a new highway on air quality, or estimating the results of a new automobile emissions exhaust system. The urban diffusion model itself should be able to account for point, line, and area sources, and the local aerodynamic effects of street canyons and building wakes. Removal or transformations due to dry or wet deposition and chemical reactions are often important. It would be best if the model included meteorological parameters such as wind speed and temperature as dependent variables, since these parameters vary significantly when air passes from rural surfaces over urban surfaces

  9. Diffuse Ceiling Ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen; Heiselberg, Per; Nielsen, Peter V.

    2014-01-01

    As a novel air distribution system, diffuse ceiling ventilation combines the suspended acoustic ceiling with ventilation supply. Due to the low-impulse supply from the large ceiling area, the system does not generate draught when supplying cold air. However, heat sources play an important role...... on thermal comfort in the occupant zone. Another characteristic of this system is its lower pressure drop compared with conventional ventilation systems, which reduces the noise problem and, at the same time, the energy consumption of the fan can be reduced. This review is based on a number of experimental...... and numerical studies on diffuse ceiling ventilation. Performance in terms of thermal comfort, air quality, pressure drop as well as radiant cooling potential are examined. Finally, a discussion on the proper design of the suspended ceiling and plenum to achieve a uniform air distribution and surface...

  10. Magnetic diffuse scattering

    International Nuclear Information System (INIS)

    Cable, J.W.

    1987-01-01

    The diffuse scattering of neutrons from magnetic materials provides unique and important information regarding the spatial correlations of the atoms and the spins. Such measurements have been extensively applied to magnetically ordered systems, such as the ferromagnetic binary alloys, for which the observed correlations describe the magnetic moment fluctuations associated with local environment effects. With the advent of polarization analysis, these techniques are increasingly being applied to study disordered paramagnetic systems such as the spin-glasses and the diluted magnetic semiconductors. The spin-pair correlations obtained are essential in understanding the exchange interactions of such systems. In this paper, we describe recent neutron diffuse scattering results on the atom-pair and spin-pair correlations in some of these disordered magnetic systems. 56 refs

  11. Diffused Religion and Prayer

    Directory of Open Access Journals (Sweden)

    Roberto Cipriani

    2011-06-01

    Full Text Available It is quite likely that the origins of prayer are to be found in ancient mourning and bereavement rites. Primeval ritual prayer was codified and handed down socially to become a deep-rooted feature of people’s cultural behavior, so much so, that it may surface again several years later, in the face of death, danger, need, even in the case of relapse from faith and religious practice. Modes of prayer depend on religious experience, on relations between personal prayer and political action, between prayer and forgiveness, and between prayer and approaches to religions. Various forms of prayer exist, from the covert-hidden to the overt-manifest kind. How can they be investigated? How can one, for instance, explore mental prayer? These issues regard the canon of diffused religion and, therefore, of diffused prayer.

  12. Building-wake diffusion

    International Nuclear Information System (INIS)

    Ramsdell, J.V.

    1988-01-01

    A recent review of building-wake diffusion models compares model predictions of centerline concentrations in building wakes with concentrations observed in experiments at seven nuclear reactors. In general, the model predictions are conservative in that they tend to predict concentrations that are greater than those actually observed. However, the models show little skill in accounting for variations in the observed concentrations. Analysis of experimental data indicates that the general form of the standard wake diffusion models is inconsistent with observed variations of concentrations in the wakes. The inconsistency is especially marked for ground-level releases. As an interim measure, multiple linear regression techniques have been used to develop a statistical building-wake model alternative to the current models. This paper describes the statistical wake model and compares it with other models

  13. Diffusion in inhomogeneous media

    Science.gov (United States)

    Donos, Aristomenis; Gauntlett, Jerome P.; Ziogas, Vaios

    2017-12-01

    We consider the transport of conserved charges in spatially inhomogeneous quantum systems with a discrete lattice symmetry. We analyze the retarded two-point functions involving the charges and the associated currents at long wavelengths, compared to the scale of the lattice, and, when the dc conductivities are finite, extract the hydrodynamic modes associated with diffusion of the charges. We show that the dispersion relations of these modes are related to the eigenvalues of a specific matrix constructed from the dc conductivities and certain thermodynamic susceptibilities, thus obtaining generalized Einstein relations. We illustrate these general results in the specific context of relativistic hydrodynamics where translation invariance is broken using spatially inhomogeneous and periodic deformations of the stress tensor and the conserved U (1 ) currents. Equivalently, this corresponds to considering hydrodynamics on a curved manifold, with a spatially periodic metric and chemical potential, and we obtain the dispersion relations for the heat and charge diffusive modes.

  14. Diffuse galactic annihilation radiation

    Science.gov (United States)

    Ramaty, R.; Lingenfelter, R. E.

    1993-01-01

    The study reports observations of positron annihilation radiation from the inner region of the Galaxy which show that there are two components of the radiation: a steady, diffuse Galactic component and a variable component from discrete, presumably compact sources. The existence of the variable component is supported by the ensemble of all narrow FOV 511 keV line observations, including recent detections with OSSE. The fit of this ensemble to a time-independent source distribution can be excluded at the approximately 3-sigma level. The same ensemble, combined with the broad FOV SMM observations of Galactic 511 keV line emission, sets constraints on the Galactic distribution of the diffuse component.

  15. Diffuse neonatal gastric infarction

    International Nuclear Information System (INIS)

    Johnson, J.F.; Woisard, K.K.; Cooper, G.L.

    1988-01-01

    Diffuse neonatal gastric infarction can be a devastating complication of invasion of the gastric wall and vessels by fungi colonizing the gastric mucosa. Even in the presence of extensive transmural necrosis, however, the radiographs do not necessarily show evidence of gastric mucosal abnormality. Instead, plain films and positive contrast studies may erroneously suggest a mechanical gastric outlet obstruction. Ancillary evidence of a devitalized viscus in a baby who appears to have complete gastric outlet obstruction should suggest the diagnosis of gastric infarction. (orig.)

  16. Diffuse neonatal gastric infarction

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.F.; Woisard, K.K.; Cooper, G.L.

    1988-02-01

    Diffuse neonatal gastric infarction can be a devastating complication of invasion of the gastric wall and vessels by fungi colonizing the gastric mucosa. Even in the presence of extensive transmural necrosis, however, the radiographs do not necessarily show evidence of gastric mucosal abnormality. Instead, plain films and positive contrast studies may erroneously suggest a mechanical gastric outlet obstruction. Ancillary evidence of a devitalized viscus in a baby who appears to have complete gastric outlet obstruction should suggest the diagnosis of gastric infarction.

  17. Technology diffusion and growth

    OpenAIRE

    Erzo G. J. Luttmer

    2009-01-01

    Suppose firms are subject to decreasing returns and permanent idiosyncratic productivity shocks. Suppose also firms can only stay in business by continuously paying a fixed cost. New firms can enter. Firms with a history of relatively good productivity shocks tend to survive and others are forced to exit. This paper identifies assumptions about entry that guarantee a stationary firm size distribution and lead to balanced growth. The range of technology diffusion mechanisms that can be conside...

  18. Diffusion bonding techniques

    International Nuclear Information System (INIS)

    Peters, R.D.

    1978-01-01

    The applications of diffusion bonding at the General Electric Neutron Devices Department are briefly discussed, with particular emphasis on the gold/gold or gold/indium joints made between metallized alumina ceramic parts in the vacuum switch tube and the crystal resonator programs. Fixtures which use the differential expansion of dissimilar metals are described and compared to one that uses hydraulic pressure to apply the necessary bonding force

  19. The evaluation of corrosion inhibitors for application to copper and copper alloy archaeological artefacts

    OpenAIRE

    Faltermeier, R.

    1995-01-01

    This thesis concerns corrosion inhibiting compounds which slow the deterioration of archaeological copper artefacts. Benzotriazole (BTA) and 2-Amino- 5-mercapto-1,3,4-thiadiazole (AMT) have been applied as corrosion inhibitors in archaeological conservation. A search was conducted for similar compounds that could be applied in the conservation of copper and copper alloys. According to a list of requirements specific to archaeological conservation, six new inhibitors were tes...

  20. Copper toxicity in sheep: the effects of repeated intravenous injections of copper sulphate

    Energy Technology Data Exchange (ETDEWEB)

    Howell, J.M.; Gopinath, C.

    1977-01-01

    Four Clun Forest, Suffolk cross sheep were given daily intravenous injections of copper sulphate. Three similar sheep acted as controls. The copper dosed sheep developed haemolysis and showed liver, kidney and brain damage similar to that seen in chronic copper poisoning. All animals survived for 30 days and two would have lived longer. Reticulocytes were produced after four days and continued to be produced, sometimes in high numbers throughout the course of the experiment. 21 references, 6 figures, 2 tables.

  1. Diffusing Best Practices

    DEFF Research Database (Denmark)

    Pries-Heje, Jan; Baskerville, Richard

    2014-01-01

    Both the practice and the research literature on information systems attach great value to the identification and dissemination of information on “best practices”. In the philosophy of science, this type of knowledge is regarded as technological knowledge because it becomes manifest in the succes...... that the behavior will be effective). These two factors were especially critical if the source context of the best practice is qualitatively different from the target context into which the organization is seeking to diffuse the best practice.......Both the practice and the research literature on information systems attach great value to the identification and dissemination of information on “best practices”. In the philosophy of science, this type of knowledge is regarded as technological knowledge because it becomes manifest...... approach. The study context is a design case in which an organization desires to diffuse its best practices across different groups. The design goal is embodied in organizational mechanisms to achieve this diffusion. The study used Theory of Planned Behavior (TPB) as a kernel theory. The artifacts...

  2. Analysis of copper flows in China from 1975 to 2010.

    Science.gov (United States)

    Zhang, Ling; Yang, Jiameng; Cai, Zhijian; Yuan, Zengwei

    2014-04-15

    By applying substance flow analysis (SFA), the paper attempts to illustrate how copper utilization pattern has changed in the anthroposphere of China from 1975 to 2010. An analytical framework is firstly established and the detailed copper cycles of the specific years 1975, 1985, 1995, 2005 and 2010 are then characterized. Major conclusions include the following: (1) Chinese copper industry has made significant progress driven by large domestic copper demand since 1970s, especially after 1990s. Also the structure of copper industry has shifted from a basic industry to a processing industry. The share of secondary copper production in total refined copper has risen from 20% in 1975 to 38% in 2010; (2) the Chinese society has experienced a rapid copper accumulation since 1990s. The annual input flow to use stage jumped from only 334 Gg (that is 0.36 kg per capita copper consumption) in 1975 to 7,916 Gg (5.90 kg per capita) in 2010; (3) a large amount of copper has to be imported to meet the huge demand, mainly involving in copper concentrate, refined copper and copper scrap. And the NIR (Net Import Ratio) of the three was 53.0%, 38.7% and 63.0% in 2010, respectively; (4) domestically produced copper scrap increased from 74.5 Gg in 1975 to 711.2 Gg in 2010. Comparing it with import scrap and domestic new scrap we found that at current stage the in-use stock is still too small to generate high quantities of copper scrap for domestic secondary copper production. (5) Major copper losses occurred through copper Mining, Refining and WM&R, with the Mining exhibited the lowest copper utilization efficiency (CUE) among the three processes, and may have the great potential for increasing copper utilization rate in China. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  3. The Pearson diffusions: A class of statistically tractable diffusion processes

    DEFF Research Database (Denmark)

    Forman, Julie Lyng; Sørensen, Michael

    classification is presented for the ergodic Pearson diffusions. The class of stationary distributions equals the full Pearson system of distributions. Well-known instances are the Ornstein-Uhlenbeck processes and the square root (CIR) processes. Also diffusions with heavy-tailed and skew marginals are included....... Special attention is given to a skew t-type distribution. Explicit formulae for the conditional moments and the polynomial eigenfunctions are derived. The analyti- cal tractability is inherited by transformed Pearson diffusions, integrated Pearson diffusions, sums of Pearson diffusions, and stochastic...

  4. Anisotropic light diffusion: an oxymoron?

    Science.gov (United States)

    Kienle, Alwin

    2007-05-25

    Light propagation in anisotropic random media is studied in the steady-state and time domains. Solutions of the anisotropic diffusion equation are compared to results obtained by the Monte Carlo method. Contrary to what has been reported so far, we find that even in the "diffusive regime" the anisotropic diffusion equation does not describe correctly the light propagation in anisotropic random media.

  5. Herausforderungen der Diffusion sozialer Innovationen

    NARCIS (Netherlands)

    Brandsen, T.

    2014-01-01

    Unter Rückgriff auf das Diffusions-Modell von Everett M. Rogers und mithilfe der Metapher der Übermittlung von Nachrichten zeigt der Autor auf, hinsichtlich welcher Aspekte sich die Diffusion sozialer Innovationen von der Diffusion anderer, besser erforschter Innovations- Typen im Wirtschaftssektor

  6. Speciation and leachability of copper in mine tailings from porphyry copper mining

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Yianatos, Juan B; Ottosen, Lisbeth M.

    2005-01-01

    Mine tailing from the El Teniente-Codelco copper mine situated in VI Region of Chile was analysed in order to evaluate the mobility and speciation of copper in the solid material. Mine tailing was sampled after the rougher flotation circuits, and the copper content was measured to 1150mgkg^-^1 dry...... matter. This tailing was segmented into fractions of different size intervals: 0-38, 38-45, 45-53, 53-75, 75-106, 106-150, 150-212, and >212@mm, respectively. Copper content determination, sequential chemical extraction, and desorption experiments were carried out for each size interval in order...

  7. Transgenic Nicotiana tabacum plants expressing a fungal copper transporter gene show enhanced acquisition of copper.

    Science.gov (United States)

    Singh, Sudhir; Korripally, Premsagar; Vancheeswaran, Ramachandran; Eapen, Susan

    2011-10-01

    The diets of two-thirds of the world's population are deficient in one or more essential elements and one of the approaches to enhance the levels of mineral elements in food crops is by developing plants with ability to accumulate them in edible parts. Besides conventional methods, transgenic technology can be used for enhancing metal acquisition in plants. Copper is an essential element, which is often deficient in human diet. With the objective of developing plants with improved copper acquisition, a high-affinity copper transporter gene (tcu-1) was cloned from fungus Neurospora crassa and introduced into a model plant (Nicotiana tabacum). Integration of the transgene was confirmed by Southern blot hybridization. Transgenic tobacco plants (T(0) and T(1)) expressing tcu-1, when grown in hydroponic medium spiked with different concentrations of copper, showed higher acquisition of copper (up to 3.1 times) compared with control plants. Transgenic plants grown in soil spiked with copper could also take up more copper compared with wild-type plants. Supplementation of other divalent cations such as Cd(2+) and Zn(2+) did not alter uptake of Cu by transgenic plants. The present study has shown that expression of a heterologous copper transporter in tobacco could enhance acquisition of copper.

  8. RECYCLING OF SCRAP AND WASTE OF COPPER AND COPPER ALLOYS IN BELARUS

    Directory of Open Access Journals (Sweden)

    S. L. Rovin

    2017-01-01

    Full Text Available The construction of a new casting and mechanical shop of unitary enterprise «Tsvetmet» in December 2015 has allowed to solve the complex problem of processing and utilization of scrap and wastes of copper and copper alloys in the Republic of Belarus. The technological processes of fire refinement of copper and manufacturing of copper rod from scrap and production of brass rod by hot pressing (extrusion of the continuously casted round billet have been mastered for the first time in the Republic of Belarus.

  9. Effort on calibration of infrared spark ablation of copper with synthetic copper standards

    Energy Technology Data Exchange (ETDEWEB)

    Wienold, Julia, E-mail: julia.wienold@bam.de; Traub, Heike; Bresch, Harald; Seeger, Stefan; Recknagel, Sebastian; Kipphardt, Heinrich

    2011-06-15

    Two types of copper samples, compact certified copper reference materials and calibration samples prepared from liquid doped, pressed copper powders, were studied in terms of accuracy of obtained calibration functions originating from infrared spark ablation. Additionally, corresponding particle size distributions of the aerosols from infrared spark ablation were recorded. It is shown that the differences in quantification results, originating from the two sets of calibration functions, could not mainly be ascribed to different particle size distributions of the two copper sample types. Possible other causes, as different ablation rates, parts of melting and differences of the chemical constitutions of the two sample types were explored.

  10. Effect of hierarchical meso–macroporous alumina-supported copper catalyst for methanol synthesis from CO2 hydrogenation

    International Nuclear Information System (INIS)

    Witoon, Thongthai; Bumrungsalee, Sittisut; Chareonpanich, Metta; Limtrakul, Jumras

    2015-01-01

    Highlights: • CO 2 hydrogenation over Cu-loaded unimodal and hierarchical alumina catalysts. • Cu-loaded hierarchical catalyst exhibited higher methanol selectivity and stability. • The presence of macropores reduced the probability of side reaction. - Abstract: Effects of pore structures of alumina on the catalytic performance of copper catalysts for CO 2 hydrogenation were investigated. Copper-loaded hierarchical meso–macroporous alumina (Cu/HAl) catalyst exhibited no significant difference in terms of CO 2 conversion with copper-loaded unimodal mesoporous alumina (Cu/UAl) catalyst. However, the selectivity to methanol and dimethyl ether of the Cu/HAl catalyst was much higher than that of the Cu/UAl catalyst. This was attributed to the presence of macropores which diminished the occurrence of side reaction by the shortening the mesopores diffusion path length. The Cu/HAl catalyst also exhibited much higher stability than the Cu/UAl catalyst due to the fast diffusion of water out from the catalyst pellets, alleviating the oxidation of metallic copper to CuO

  11. Determination of Critical Conditions for the Formation of Electrodeposited Copper Structures Suitable for Electrodes in Electrochemical Devices

    Directory of Open Access Journals (Sweden)

    Miomir G. Pavlovic

    2007-01-01

    Full Text Available Electrodeposition of copper from acid sulfate solutions at overpotentials on theplateau of the limiting diffusion current density and at higher overpotentials wasexamined. The average current efficiencies for hydrogen evolution reaction aredetermined by a measurement of the quantity of evolved hydrogen and the overallelectrodeposition current as a function of electrodeposition time, while morphologies ofcopper deposits are examined by the use of the scanning electron microscopy (SEMtechnique. It is found that the open and porous structures of copper deposits (denoted andas honeycomb – like copper structures, suitable for electrodes in electrochemical devicessuch as fuel cells and chemical sensors, were reached by electrodeposition processesfrom solutions with the lower concentrations of Cu (II ions (0.15 M CuSO4 and less in0.50 M H2SO4 at overpotentials outside the plateau of the limiting diffusion currentdensity at which the quantity of evolved hydrogen was enough to change hydrodynamicconditions in the near – electrode layer. The main characteristics of these copperstructures were craters or holes formed primarily due to the attachment hydrogen bubbleswith agglomerates of copper grains between them.

  12. Interface structure of Be/DSCu diffusion bonding

    Energy Technology Data Exchange (ETDEWEB)

    Makino, T.; Iwadachi, T. [NGK Insulators Ltd., Nagoya (Japan)

    1998-01-01

    Beryllium is used as plasma facing components of the first wall on ITER. Dispersion-Strengthened Copper (DSCu) is used as heat sink material by joining to Be because DSCu has high thermal conductivity and strength. In this study, Be/DSCu diffusion bonding tests using the interlayer of Al, Ni, Nb, Ti, Zr and Be-Cu alloy have been conducted to choose the suitable interlayer materials. As a result of the shear strength tests, Be/DSCu joints by using Be-Cu alloy interlayer showed the strength of about 200 MPa. Diffusion bonding tests using Be-Cu alloy interlayer or no interlayer (direct bonding) at the range of temperature from 600degC to 850degC have been conducted to identify the effect of bonding temperature and time on interface formation and strength. The thickness of diffusion layer was proportional to a square root of bonding time by diffusion controlled process. The shear strength is controlled by the formation of intermetallic layer at Be side. (author)

  13. Radiation-enhanced thermal processes during implantation of gold into copper

    Energy Technology Data Exchange (ETDEWEB)

    Perret, N.E.; King, B.V.; Dastoor, P.C. [Newcastle Univ., NSW (Australia). Dept. of Physics

    1996-12-31

    A copper (100) single crystal has been implanted with gold ions at temperatures ranging from 133 K to 673 K. Rutherford Backscattering Spectroscopy (RBS) has been used to observe the changes in the gold implant distribution that occur as a function of the sample temperature during implantation. Two distinct effects have been observed. Firstly the gold implant distribution, as a function of depth, broadens with sample temperature. This broadening of the gold depth profile is most marked at temperatures above 473 K. Secondly, the gold is implanted deeper into the copper crystal as the sample temperature is increased. These results are discussed in terms of radiation enhanced diffusion and radiation-induced segregation processes. 10 refs., 3 figs.

  14. Carboxymethylated chitosan-stabilized copper nanoparticles: a promise to contribute a potent antifungal and antibacterial agent

    Energy Technology Data Exchange (ETDEWEB)

    Tantubay, Sangeeta, E-mail: sang.chem2@gmail.com [Indian Institute of Technology Kharagpur, Department of Chemistry (India); Mukhopadhyay, Sourav K. [Indian Institute of Technology Kharagpur, Department of Biotechnology (India); Kalita, Himani; Konar, Suraj [Indian Institute of Technology Kharagpur, Department of Chemistry (India); Dey, Satyahari [Indian Institute of Technology Kharagpur, Department of Biotechnology (India); Pathak, Amita, E-mail: ami@chem.iitkgp.ernet.in; Pramanik, Panchanan, E-mail: ppramanik1946@yahoo.in, E-mail: pramanik1946@gmail.com [Indian Institute of Technology Kharagpur, Department of Chemistry (India)

    2015-06-15

    Carboxymethylated chitosan (CMC)-stabilized copper nanoparticles (Cu-NPs) have been synthesized via chemical reduction of copper(II)–CMC complex in aqueous medium by hydrazine under microwave irradiation in ambient atmosphere. Structural morphology, phase, and chemical compositions of CMC-stabilized Cu-NPs (CMC–Cu-NPs) have been analyzed through high-resolution transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Antifungal and antibacterial activities of CMC–Cu-NPs have been evaluated against Candida tropicalis and Escherichia coli through agar well diffusion method, broth microdilution assay, live–dead assay, and microscopic observation. Antimicrobial activity of spherical CMC–Cu-NPs (∼4–15 nm of diameters) has been observed to be significant for both C. tropicalis and E. coli. The cytotoxicity study indicates that CMC–Cu-NPs have no significant toxic effect against normal cell line, L929.

  15. The effect of concentration on the electrocrystallization mechanism for copper on platinum ultramicroelectrodes

    Directory of Open Access Journals (Sweden)

    Barin Cláudia S.

    2000-01-01

    Full Text Available The mechanism of copper electrocrystallization on Pt ultramicroelectrode surfaces has been studied by cyclic voltammetry, chronoamperometry and ex situ atomic force microscopy in acid solutions containing different Cu2+ concentrations. To analyze the potentiostatic transients a new model developed in our laboratories that takes into account spherical diffusion towards a disc-shaped ultramicroelectrode was used. A mechanistic change from progressive to instantaneous nucleation was observed when the Cu2+ concentration was increased from 0.01 to 0.1 mol dm-3. The shape and distribution of the nuclei formed on the surface were investigated by AFM. The dependence of the nucleation rate with potential was analyzed in terms of the atomistic theory of electrocrystallization and the results suggest the presence of only one copper atom in the critical nucleus.

  16. Radiation-enhanced thermal processes during implantation of gold into copper

    International Nuclear Information System (INIS)

    Perret, N.E.; King, B.V.; Dastoor, P.C.

    1996-01-01

    A copper (100) single crystal has been implanted with gold ions at temperatures ranging from 133 K to 673 K. Rutherford Backscattering Spectroscopy (RBS) has been used to observe the changes in the gold implant distribution that occur as a function of the sample temperature during implantation. Two distinct effects have been observed. Firstly the gold implant distribution, as a function of depth, broadens with sample temperature. This broadening of the gold depth profile is most marked at temperatures above 473 K. Secondly, the gold is implanted deeper into the copper crystal as the sample temperature is increased. These results are discussed in terms of radiation enhanced diffusion and radiation-induced segregation processes. 10 refs., 3 figs

  17. Simulation of through via bottom—up copper plating with accelerator for the filling of TSVs

    International Nuclear Information System (INIS)

    Wu Heng; Tang Zhen'an; Wang Zhu; Cheng Wan; Yu Daquan

    2013-01-01

    Filling high aspect ratio through silicon vias (TSVs) without voids and seams by copper plating is one of the technical challenges for 3D integration. Bottom—up copper plating is an effective solution for TSV filling. In this paper, a new numerical model was developed to simulate the electrochemical deposition (ECD) process, and the influence of an accelerator in the electrolyte was investigated. The arbitrary Lagrange—Eulerian (ALE) method for solving moving boundaries in the finite element method (FEM) was used to simulate the electrochemical process. In the model, diffusion coefficient and adsorption coefficient were considered, and then the time-resolved evolution of electroplating profiles was simulated with ion concentration distribution and the electric current density. (semiconductor technology)

  18. Electrodialytic remediation of copper mine tailings

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Rojo, A.; Ottpsen, Lisbeth M.

    2005-01-01

    Mining activities in Chile have generated large amounts of solid waste, which have been deposited in mine tailing impoundments. These impoundments cause concern to the communities due to dam failures or natural leaching to groundwater and rivers.This work shows the laboratory results of nine...... electrodialytic remediation experiments on copper mine tailings. The results show that electric current could remove copper from watery tailing if the potential gradient was higher than 2V/cm during 21 days. With addition of sulphuric acid, the process was enhanced because the pH decreased to around 4......, and the copper by this reason was released in the solution. Furthermore, with acidic tailing the potential gradient was less than 2V/cm.The maximum copper removal reached in the anode side was 53% with addition of sulphuric acid in 21 days experiment at 20V using approximately 1.8kg mine tailing on dry basis...

  19. Thermally modified bentonite clay for copper removal

    International Nuclear Information System (INIS)

    Bertagnolli, C.; Kleinübing, S.J.; Silva, M.G.C.

    2011-01-01

    Bentonite clay coming from Pernambuco was thermally modified in order to increase its affinity and capacity in the copper removal in porous bed. The application of this procedure is justified by the low cost of clay, their abundance and affinity for various metal ions. Thermally treatment modifies the clay adsorption properties enables its use in porous bed system, with the increase in surface area and mechanical strength. The material was characterized by x-ray diffraction, thermogravimetric analysis and N 2 physisorption. Then tests were carried out for adsorption of copper in various experimental conditions and evaluated the mass transfer zone, useful and total adsorbed removal amounts and total copper removal percentage. The results showed that the clay treated at higher temperature showed higher copper removal. (author)

  20. Copper catalysed synthesis of indolylquinazolinone alkaloid ...

    Indian Academy of Sciences (India)

    We describe the total synthesis of indolylquinazolinone alkaloid bouchardatine and some of the quinazolinone derivatives. The aerobic oxidation induced by copper(I) bromide, followed by Vilsmeier-Haack formylation gives the natural product bouchardatine alkaloid in good yield.

  1. Purity test for copper-plating solutions

    Science.gov (United States)

    Mansfeld, F. B.

    1977-01-01

    Electrode configuration can be used to measure extent of impurities in acid-copper plating solution. It can be inserted into any plating tank and will show whether bath is clean or contaminated, within fifteen minutes.

  2. Electroless Copper Deposition: A Sustainable Approach

    Science.gov (United States)

    Kutnahorsky, Marika Renee

    A sustainable electroless copper coating process was developed for plating automotive fasteners shaped from AISI 9255 low carbon, high silicon steel. The objective was to minimize the ionic and organic species present in each step of the plating process. A sulfuric acid solution inhibited with quinine was defined to clean the steel prior to plating. The corrosivity of the solution was examined through electrochemical and weight loss measurements to evaluate the efficiency of the cleaning process at high temperatures and high acid concentrations. An electroless copper coating process was then developed using a simple copper sulfate chemistry inhibited with quinine to extend the possible operating window. Finally, benzotriazole was evaluated as a possible anti-oxidant coating. Accelerated thioacetamide corrosion tests were used to evaluate the corrosion inhibition of benzotriazole on copper coatings.

  3. Antimicrobial Properties of Copper Nanoparticles and Amino Acid Chelated Copper Nanoparticles Produced by Using a Soya Extract

    OpenAIRE

    DeAlba-Montero, I.; Guajardo-Pacheco, Jes?s; Morales-S?nchez, Elpidio; Araujo-Mart?nez, Rene; Loredo-Becerra, G. M.; Mart?nez-Casta??n, Gabriel-Alejandro; Ruiz, Facundo; Compe?n Jasso, M. E.

    2017-01-01

    This paper reports a comparison of the antibacterial properties of copper-amino acids chelates and copper nanoparticles against Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. These copper-amino acids chelates were synthesized by using a soybean aqueous extract and copper nanoparticles were produced using as a starting material the copper-amino acids chelates species. The antibacterial activity of the samples was evaluated by using the standard microdilution method (CLSI M...

  4. Treatment of Copper Converter Flue Dust for the Separation of Metallic/non-metallic Copper by Hydrometallurgical Processing

    OpenAIRE

    Martín, M. I.; López-Delgado, Aurora; López Gómez, Félix Antonio; Gómez Coedo, Aurora; Dorado López, María Teresa; Alguacil, Francisco José

    2003-01-01

    A hydrometallurgical procedure for the separation of copper soluble species from metallic copper of a copper converter flue dust was studied. The high content of metallic copper in the starting material made unique a procedure of such characteristics for the treatment of this secondary copper resource. The procedure consists of leaching and solvent extraction operations. Leaching was carried out under atmospheric conditions using sulphuric acid. Under various experimental conditions the metal...

  5. Electrodialytic Remediation of Copper Mine Tailings

    DEFF Research Database (Denmark)

    Hansen, H.K.; Rojo, A.; Ottosen, L.M.

    2012-01-01

    This work compares and evaluates sixteen electrodialytic laboratory remediation experiments on copper mine tailings. Different parameters were analysed, such as remediation time, addition of desorbing agents, and the use of pulsed electrical fields.......This work compares and evaluates sixteen electrodialytic laboratory remediation experiments on copper mine tailings. Different parameters were analysed, such as remediation time, addition of desorbing agents, and the use of pulsed electrical fields....

  6. Pharmacological Properties of Nanometals (Silver, Copper, Iron

    Directory of Open Access Journals (Sweden)

    Chekman, I.S.

    2015-01-01

    Full Text Available The article summarizes the results of studies on the pharmacological, toxicological and specific properties of nanometals (silver, iron, copper. It is established that nanoparticles of silver, copper, iron exhibit antimicrobial action. Acute toxicity of nanometals depends on their nature, administration route and animal sex. Effects on heart activity and hemodynamic status as well as erythrocyte osmotic fragility have dose-dependent nature.

  7. Bioremediation: Copper Nanoparticles from Electronic-waste

    OpenAIRE

    D. R. MAJUMDER

    2012-01-01

    A single-step eco-friendly approach has been employed to synthesize copper nanoparticles. The superfast advancement in the field of electronics has given rise to a new type of waste called electronic waste. Since the physical and chemical recycling procedures have proved to be hazardous, the present work aims at the bioremediation of e-waste in order to recycle valuable metals. Microorganisms such as Fusarium oxysporum and Pseudomonas sp. were able to leach copper (84-130 nm) from integrated ...

  8. Atomistic simulations of dislocation processes in copper

    DEFF Research Database (Denmark)

    Vegge, T.; Jacobsen, K.W.

    2002-01-01

    We discuss atomistic simulations of dislocation processes in copper based on effective medium theory interatomic potentials. Results on screw dislocation structures and processes are reviewed with particular focus on point defect mobilities and processes involving cross slip. For example, the sta......We discuss atomistic simulations of dislocation processes in copper based on effective medium theory interatomic potentials. Results on screw dislocation structures and processes are reviewed with particular focus on point defect mobilities and processes involving cross slip. For example...

  9. Copper stable isotopes to trace copper behavior in wetland systems.

    Science.gov (United States)

    Babcsányi, Izabella; Imfeld, Gwenaël; Granet, Mathieu; Chabaux, François

    2014-05-20

    Wetlands are reactive zones of the landscape that can sequester metals released by industrial and agricultural activities. Copper (Cu) stable isotope ratios (δ(65)Cu) have recently been used as tracers of transport and transformation processes in polluted environments. Here, we used Cu stable isotopes to trace the behavior of Cu in a stormwater wetland receiving runoff from a vineyard catchment (Alsace, France). The Cu loads and stable isotope ratios were determined in the dissolved phase, suspended particulate matter (SPM), wetland sediments, and vegetation. The wetland retained >68% of the dissolved Cu and >92% of the SPM-bound Cu, which represented 84.4% of the total Cu in the runoff. The dissolved Cu became depleted in (65)Cu when passing through the wetland (Δ(65)Cuinlet-outlet from 0.03‰ to 0.77‰), which reflects Cu adsorption to aluminum minerals and organic matter. The δ(65)Cu values varied little in the wetland sediments (0.04 ± 0.10‰), which stored >96% of the total Cu mass within the wetland. During high-flow conditions, the Cu flowing out of the wetland became isotopically lighter, indicating the mobilization of reduced Cu(I) species from the sediments and Cu reduction within the sediments. Our results demonstrate that the Cu stable isotope ratios may help trace Cu behavior in redox-dynamic environments such as wetlands.

  10. Particle diffusion in a spheromak

    International Nuclear Information System (INIS)

    Meyerhofer, D.D.; Levinton, F.M.; Yamada, M.

    1988-01-01

    The local carbon particle diffusion coefficient was measured in the Proto S-1/C spheromak using a test particle injection scheme. When the plasma was not in a force-free Taylor state, and when there were pressure gradients in the plasma, the particle diffusion was five times that predicted by Bohm and was consistent with collisional drift wave diffusion. The diffusion appears to be driven by correlations of the fluctuating electric field and density. During the decay phase of the discharge when the plasma was in the Taylor state, the diffusion coefficient of the carbon was classical. 23 refs., 4 figs

  11. Advanced diffusion processes and phenomena

    CERN Document Server

    Öchsner, Andreas; Belova, Irina

    2014-01-01

    This topical volume on Advanced Diffusion Processes and Phenomena addresses diffusion in a wider sense of not only mass diffusion but also heat diffusion in fluids and solids. Both diffusion phenomena play an important role in the characterization of engineering materials and corresponding structures. Understanding these different transport phenomena at many levels, from atomistic to macro, has therefore long attracted the attention of many researchers in materials science and engineering and related disciplines. The present topical volume captures a representative cross-section of some of the

  12. Dietary management of labrador retrievers with subclinical hepatic copper accumulation.

    Science.gov (United States)

    Fieten, H; Biourge, V C; Watson, A L; Leegwater, P A J; van den Ingh, T S G A M; Rothuizen, J

    2015-01-01

    Genetic and environmental factors, including dietary copper intake, contribute to the pathogenesis of copper-associated hepatitis in Labrador retrievers. Clinical disease is preceded by a subclinical phase in which copper accumulates in the liver. To investigate the effect of a low-copper, high-zinc diet on hepatic copper concentration in Labrador retrievers with increased hepatic copper concentrations. Twenty-eight clinically healthy, client-owned Labrador retrievers with a mean hepatic copper concentration of 919 ± 477 mg/kg dry weight liver (dwl) that were related to dogs previously diagnosed with clinical copper-associated hepatitis. Clinical trial in which dogs were fed a diet containing 1.3 ± 0.3 mg copper/Mcal and 64.3 ± 5.9 mg zinc/Mcal. Hepatic copper concentrations were determined in liver biopsy samples approximately every 6 months. Logistic regression was performed to investigate effects of sex, age, initial hepatic copper concentration and pedigree on the ability to normalize hepatic copper concentrations. In responders (15/28 dogs), hepatic copper concentrations decreased from a mean of 710 ± 216 mg/kg dwl copper to 343 ± 70 mg/kg dwl hepatic copper after a median of 7.1 months (range, 5.5-21.4 months). Dogs from a severely affected pedigree were at increased risk for inability to have their hepatic copper concentrations normalized with dietary treatment. Feeding a low-copper, high-zinc diet resulted in a decrease in hepatic copper concentrations in a subset of clinically normal Labrador retrievers with previous hepatic copper accumulation. A positive response to diet may be influenced by genetic background. Determination of clinical benefit requires further study. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  13. Cellular membrane accommodation of copper-induced oxidative conditions in the coral Seriatopora caliendrum

    International Nuclear Information System (INIS)

    Tang, Chuan-Ho; Lin, Ching-Yu; Lee, Shu-Hui; Wang, Wei-Hsien

    2014-01-01

    Highlights: • Coral cells alter membrane lipid to accommodate copper-induce oxidative conditions • Coral membrane repair occur due to lipid alterations • Zooxanthellae release results from membrane repair by symbiosome fusion • Copper-induced lipid alterations perturb membrane-related functions in coral cells • Copper chronic effect on coral fitness are related to long-term membrane perturbation - Abstract: Oxidative stress has been associated with copper-induced toxicity in scleractinian corals. To gain insight into the accommodation of the cellular membrane to oxidative conditions, a pocilloporid coral, Seriatopora caliendrum, was exposed to copper at distinct, environmentally relevant dose for various lengths of time. Glycerophosphocholine profiling of the response of the coral to copper exposure was characterized using a validated method. The results indicate that coral lipid metabolism is programmed to induce membrane alterations in response to the cellular deterioration that occurs during the copper exposure period. Decreasing lyso-phosphatidylcholines and exchanging polyunsaturated phosphatidylcholines for polyunsaturated plasmanylcholines were the initial actions taken to prevent membrane permeabilization. To relax/resist the resulting membrane strain caused by cell/organelle swelling, the coral cells inversely exchanged polyunsaturated plasmanylcholines for polyunsaturated phosphatidylcholines and further increased the levels of monounsaturated glycerophosphocholines. At the same time, the levels of saturated phosphatidylcholines were also increased to increase membrane rigidity and protect against oxidative attack. Interestingly, such alterations in lipid metabolism were also required for membrane fusion to repair the deteriorated membranes by repopulating them with proximal lipid reservoirs, similar to symbiosome membranes. Additionally, increasing saturated and monounsaturated plasmanylcholines and inhibiting the suppression of saturated lyso

  14. Copper accumulation in senescent cells: Interplay between copper transporters and impaired autophagy

    Directory of Open Access Journals (Sweden)

    Shashank Masaldan

    2018-06-01

    Full Text Available Cellular senescence is characterized by irreversible growth arrest incurred through either replicative exhaustion or by pro-oncogenic cellular stressors (radioactivity, oxidative stress, oncogenic activation. The enrichment of senescent cells in tissues with age has been associated with tissue dyshomeostasis and age-related pathologies including cancers, neurodegenerative disorders (e.g. Alzheimer's, Parkinson's, etc. and metabolic disorders (e.g. diabetes. We identified copper accumulation as being a universal feature of senescent cells [mouse embryonic fibroblasts (MEF, human prostate epithelial cells and human diploid fibroblasts] in vitro. Elevated copper in senescent MEFs was accompanied by elevated levels of high-affinity copper uptake protein 1 (Ctr1, diminished levels of copper-transporting ATPase 1 (Atp7a (copper export and enhanced antioxidant defence reflected by elevated levels of glutathione (GSH, superoxide dismutase 1 (SOD1 and glutaredoxin 1 (Grx1. The levels of intracellular copper were further increased in senescent MEFs cultured in copper supplemented medium and in senescent Mottled Brindled (Mobr MEFs lacking functional Atp7a. Finally, we demonstrated that the restoration/preservation of autophagic-lysosomal degradation in senescent MEFs following rapamycin treatment correlated with attenuation of copper accumulation in these cells despite a further decrease in Atp7a levels. This study for the first time establishes a link between Atp7a and the autophagic-lysosomal pathway, and a requirement for both to effect efficient copper export. Such a connection between cellular autophagy and copper homeostasis is significant, as both have emerged as important facets of age-associated degenerative disease. Keywords: Senescence, Copper, Ageing, Homeostasis, Autophagy

  15. Calculation and optimization of copper and uranium isolation process according to two-stage ion exchange scheme

    International Nuclear Information System (INIS)

    Sorochan, A.M.; Saldadze, K.M.; Kats, Eh.M.; Komarova, I.V.; Pron', S.V.; Stroganova, N.V.

    1981-01-01

    A variant of a two-stage scheme of ion exchange isolation of copper and uranium from seawater is suggested. Industrial anionites - AN-31 for copper and AN-2F for uranium are used at the first stage. A solution for linear isotherm and inner diffusion is used to describe the dynamics of microcomponent sorption on the anionites of the first stage. The adequate character of the given model of sorption is confirmed by the agreement between the calculation and experiment. Copper and uranium desorption from anionites is realized with 0.5 mol/l HCl. The optimization of the first stage is carried out taking account of expenditures for electrical energy, ionite and reagents. Initial data on copper and uranium sorption at semiindustrial selective sorbents of the second stage (ANKB-2 for copper and KF-7 for uranium) from 0.5 mol/l HCl solution are obtained, which helped to calculate regimes of the second stage operation to the given ion overshoot [ru

  16. Diffusion in amorphous media

    Science.gov (United States)

    Iotov, Mihail S.

    The goals of this research are twofold: First, to develop methods and tools for studying problems in chemistry, material science and biology, as well as accurate prediction of the properties of structures and materials of importance to those fields. Second, use those tools to apply the methods to practical problems. In terms of methodology development this thesis focuses on two topics: One: Development of a massively parallel computer program to perform electronic, atomic, molecular levels simulations of problems in chemistry, material science and biology. This computer program uses existing and emerging hardware platforms and parallel tools and is based on decades long research in computer modeling and algorithms. We report on that development in Chapter 3. Two: Development of tools for Molecular Dynamics simulation and methods and tools for course-grained meso-scale modeling of transport properties and especially diffusion of gas penetrants in polymers. We have formulated a new method for extracting coarse-grained information from short (0.2-0.5 nanoseconds [ns]) MD simulations and use this in a meso-scale simulation to calculate diffusion constants in polymer matrices. This is a grid-based method, which calculates the average probability of each grid point of being a void and performs constrained and biased Monte Carlo (MC) dynamics to reach much longer time regimes than possible in MD. The MC method mimics the three regimes of mean square deviation (MSD) behavior seen in MD, thus accounting for the proper mobility of the voids and the compressibility of the polymer matrix. Theoretical discussions and justification for the method is presented in chapter 6. Initial results on He diffusion in a low-density polyethylene (PE) matrix are presented in chapter 7. The behavior at different temperatures follows closely the trend observed from calibrating long term MD for this particular system.

  17. The diffuse ensemble filter

    Directory of Open Access Journals (Sweden)

    X. Yang

    2009-07-01

    Full Text Available A new class of ensemble filters, called the Diffuse Ensemble Filter (DEnF, is proposed in this paper. The DEnF assumes that the forecast errors orthogonal to the first guess ensemble are uncorrelated with the latter ensemble and have infinite variance. The assumption of infinite variance corresponds to the limit of "complete lack of knowledge" and differs dramatically from the implicit assumption made in most other ensemble filters, which is that the forecast errors orthogonal to the first guess ensemble have vanishing errors. The DEnF is independent of the detailed covariances assumed in the space orthogonal to the ensemble space, and reduces to conventional ensemble square root filters when the number of ensembles exceeds the model dimension. The DEnF is well defined only in data rich regimes and involves the inversion of relatively large matrices, although this barrier might be circumvented by variational methods. Two algorithms for solving the DEnF, namely the Diffuse Ensemble Kalman Filter (DEnKF and the Diffuse Ensemble Transform Kalman Filter (DETKF, are proposed and found to give comparable results. These filters generally converge to the traditional EnKF and ETKF, respectively, when the ensemble size exceeds the model dimension. Numerical experiments demonstrate that the DEnF eliminates filter collapse, which occurs in ensemble Kalman filters for small ensemble sizes. Also, the use of the DEnF to initialize a conventional square root filter dramatically accelerates the spin-up time for convergence. However, in a perfect model scenario, the DEnF produces larger errors than ensemble square root filters that have covariance localization and inflation. For imperfect forecast models, the DEnF produces smaller errors than the ensemble square root filter with inflation. These experiments suggest that the DEnF has some advantages relative to the ensemble square root filters in the regime of small ensemble size, imperfect model, and copious

  18. Diffusion in silicon isotope heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Silvestri, Hughes Howland [Univ. of California, Berkeley, CA (United States)

    2004-01-01

    The simultaneous diffusion of Si and the dopants B, P, and As has been studied by the use of a multilayer structure of isotopically enriched Si. This structure, consisting of 5 pairs of 120 nm thick natural Si and 28Si enriched layers, enables the observation of 30Si self-diffusion from the natural layers into the 28Si enriched layers, as well as dopant diffusion from an implanted source in an amorphous Si cap layer, via Secondary Ion Mass Spectrometry (SIMS). The dopant diffusion created regions of the multilayer structure that were extrinsic at the diffusion temperatures. In these regions, the Fermi level shift due to the extrinsic condition altered the concentration and charge state of the native defects involved in the diffusion process, which affected the dopant and self-diffusion. The simultaneously recorded diffusion profiles enabled the modeling of the coupled dopant and self-diffusion. From the modeling of the simultaneous diffusion, the dopant diffusion mechanisms, the native defect charge states, and the self- and dopant diffusion coefficients can be determined. This information is necessary to enhance the physical modeling of dopant diffusion in Si. It is of particular interest to the modeling of future electronic Si devices, where the nanometer-scale features have created the need for precise physical models of atomic diffusion in Si. The modeling of the experimental profiles of simultaneous diffusion of B and Si under p-type extrinsic conditions revealed that both species are mediated by neutral and singly, positively charged Si self-interstitials. The diffusion of As and Si under extrinsic n-type conditions yielded a model consisting of the interstitialcy and vacancy mechanisms of diffusion via singly negatively charged self-interstitials and neutral vacancies. The simultaneous diffusion of P and Si has been modeled on the basis of neutral and singly negatively charged self-interstitials and neutral and singly

  19. Diffusion or bulk flow

    DEFF Research Database (Denmark)

    Schulz, Alexander

    2015-01-01

    assimilate movement includes an apoplasmic step, this mode is called apoplasmic loading. Well established is also the polymer-trap loading mode, where the phloem-transport sugars are raffinose-family oligomers in herbaceous plants. Also this mode depends on the investment of energy, here for sugar...... is currently matter of discussion, called passive symplasmic loading. Based on the limited material available, this review compares the different loading modes and suggests that diffusion is the driving force in apoplasmic loaders, while bulk flow plays an increasing role in plants having a continuous...

  20. Preventing Addiction.

    Science.gov (United States)

    Moore, Susan Fordney

    The purpose of this paper is to provide the beginning counselor with an overview of prevention concepts. Prevention is a relatively new emphasis in community efforts to stem the rising costs of substance abuse and other high-risk behaviors. The paper discusses agent, host, and environmental prevention models and how they relate to causal theories…