WorldWideScience

Sample records for aluminium arsenides

  1. Toxicity of indium arsenide, gallium arsenide, and aluminium gallium arsenide.

    Science.gov (United States)

    Tanaka, Akiyo

    2004-08-01

    Gallium arsenide (GaAs), indium arsenide (InAs), and aluminium gallium arsenide (AlGaAs) are semiconductor applications. Although the increased use of these materials has raised concerns about occupational exposure to them, there is little information regarding the adverse health effects to workers arising from exposure to these particles. However, available data indicate these semiconductor materials can be toxic in animals. Although acute and chronic toxicity of the lung, reproductive organs, and kidney are associated with exposure to these semiconductor materials, in particular, chronic toxicity should pay much attention owing to low solubility of these materials. Between InAs, GaAs, and AlGaAs, InAs was the most toxic material to the lung followed by GaAs and AlGaAs when given intratracheally. This was probably due to difference in the toxicity of the counter-element of arsenic in semiconductor materials, such as indium, gallium, or aluminium, and not arsenic itself. It appeared that indium, gallium, or aluminium was toxic when released from the particles, though the physical character of the particles also contributes to toxic effect. Although there is no evidence of the carcinogenicity of InAs or AlGaAs, GaAs and InP, which are semiconductor materials, showed the clear evidence of carcinogenic potential. It is necessary to pay much greater attention to the human exposure of semiconductor materials.

  2. Effect of gallium aluminium arsenide diode laser therapy on Porphyromonas gingivalis in chronic periodontitis: a randomized controlled trial.

    Science.gov (United States)

    Alzoman, H A; Diab, H M

    2016-11-01

    The aim of this randomized, controlled trial was to evaluate the effects of 685-nm gallium aluminium arsenide (GaAlAs) diode laser therapy (1.6 J cm -2 ) as an adjunct to scaling and root planing in the treatment of chronic periodontitis. Thirty-two patients aged 35-60 years old who had chronic periodontitis met the eligibility criteria. They were randomly assigned to two equal groups: scaling and root planing were performed in the SRP group, while scaling, root planing and laser irradiation of periodontal pockets were performed in the SRP + DL group. Subgingival plaque samples were subjected to polymerase chain reaction (PCR) to detect P. gingivalis-colonized sites, and common clinical indices were evaluated before and 2 months after treatment. Clinical examination included gingival index (GI), plaque index (PI), probing depth (PD), clinical attachment level (CAL) and gingival bleeding index (GBI), all of which were recorded. Data from 30 patients [19 women and 11 men; mean age, 48.4 (5.4) years old] were analysed. There were statistically significant improvements in GI, PD, CAL and GBI for the SRP + DL group compared to SRP group but no significant difference in PI between the groups. Additionally, the percentage of P. gingivalis-positive sites in the SRP + DL group decreased from 80% (12/15) to 20% (3/15) after laser irradiation (P < 0.05). No significant changes were noted in the SRP group. GaAlAs diode laser irradiation of diseased periodontal pockets at 685 nm and 1.6 J cm -2 seemed to be an effective adjuvant to mechanical instrumentation to treat chronic periodontitis. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Effect of low-energy gallium-aluminum-arsenide and aluminium gallium indium phosphide laser irradiation on the viability of C2C12 myoblasts in a muscle injury model.

    Science.gov (United States)

    Ferreira, Marcos Paulo Pinheiro; Ferrari, Raquel Agnelli Mesquita; Gravalos, Erick Diomedesse; Martins, Manoela Domingues; Bussadori, Sandra Kalil; Gonzalez, Daniela Aparecida Biasotto; Fernandes, Kristianne Porta Santos

    2009-12-01

    To evaluate the effect of phototherapy on the viability of cultured C2C12 myoblasts under different nutritional conditions (muscle injury model) using low-energy gallium-aluminum-arsenide (GaAlAs) and aluminium-gallium-indium-phosphide (InGaAlP) lasers with different wavelengths and powers. The beneficial effects of phototherapy using low-energy lasers depend on irradiation parameters and type of laser used, but there are no data in the literature on C2C12 myoblasts proliferation after phototherapy with GaAlAs and InGaAlP lasers. A C2C12 cell line cultured in regular (10% fetal bovine serum, FBS) and nutrient-deficient (5% FBS) media were irradiated with low-energy GaAlAs (660 nm) and InGaAlP (780 nm) lasers with energy densities of 3.8, 6.3, and 10 J/cm2, and 3.8, 10, and 17.5 J/cm2, respectively. Cell proliferation was assessed indirectly 24 h after irradiation by measuring the mitochondrial activity and using the crystal violet assay. There were no significant differences in cell viability between laser-treated myoblasts and control cultures for all tested parameters after 24 h of cell culture, although cell cultures grown in regular nutrient medium supplemented with 10% FBS exhibited higher growth rates than cultures, irradiated or not, grown in nutrient-deficient medium. Laser phototherapy did not improve C2C12 viability under regular or nutrient-deficient (muscle injury model) conditions using the above parameters.

  4. Gallium Arsenide Domino Circuit

    Science.gov (United States)

    Yang, Long; Long, Stephen I.

    1990-01-01

    Advantages include reduced power and high speed. Experimental gallium arsenide field-effect-transistor (FET) domino circuit replicated in large numbers for use in dynamic-logic systems. Name of circuit denotes mode of operation, which logic signals propagate from each stage to next when successive stages operated at slightly staggered clock cycles, in manner reminiscent of dominoes falling in a row. Building block of domino circuit includes input, inverter, and level-shifting substages. Combinational logic executed in input substage. During low half of clock cycle, result of logic operation transmitted to following stage.

  5. Aluminium bridges, aluminium bridge decks

    NARCIS (Netherlands)

    Soetens, F.; Straalen, IJ.J. van

    2003-01-01

    Applications of aluminium have grown considerably in building and civil engineering the last decade. In building and civil engineering the increase of aluminium applications is due to various aspects like light weight, durability and maintenance, use of extrusions, and esthetics. The paper starts

  6. Doped Aluminum Gallium Arsenide (AlGaAs)/Gallium Arsenide (GaAs) Photoconductive Semiconductor Switch (PCSS) Fabrication

    Science.gov (United States)

    2016-09-27

    ARL-TR-7819 ● SEP 2016 US Army Research Laboratory Doped Aluminum Gallium Arsenide (AlGaAs)/Gallium Arsenide (GaAs...Laboratory Doped Aluminum Gallium Arsenide (AlGaAs)/Gallium Arsenide (GaAs) Photoconductive Semiconductor Switch (PCSS) Fabrication by...Report 3. DATES COVERED (From - To) January 2016–September 2016 4. TITLE AND SUBTITLE Doped Aluminum Gallium Arsenide (AlGaAs)/Gallium Arsenide (GaAs

  7. Large grain gallium arsenide thin films

    Science.gov (United States)

    Chu, S. S.; Chu, T. L.; Firouzi, H.; Han, Y. X.; Chen, W. J.; Wang, Q. H.

    Polycrystalline gallium arsenide films deposited on tungsten/graphite substrates have been used for the fabrication of thin film solar cells. Gallium arsenide films deposited on foreign substrates of 10 microns or less thickness exhibit, in most cases, pronounced shunting effects due to grain boundaries. MOS solar cells of 9 sq cm area with an AM1 efficiency of 8.5 percent and p(+)/n/n(+) homojunction solar cells of 1 sq cm area with an AM1 efficiency of 8.8 percent have been prepared. However, in order to further improve the conversion efficiency before the development of effective passivation techniques, gallium arsenide films with large and uniform grain structure are necessary. The large grain gallium arsenide films have been prepared by using (1) the arsine treatment of a thin layer of molten gallium on the substrate surface and (2) the recrystallized germanium films on tungsten/graphite as substrates.

  8. Aluminium in human sweat.

    Science.gov (United States)

    Minshall, Clare; Nadal, Jodie; Exley, Christopher

    2014-01-01

    It is of burgeoning importance that the human body burden of aluminium is understood and is measured. There are surprisingly few data to describe human excretion of systemic aluminium and almost no reliable data which relate to aluminium in sweat. We have measured the aluminium content of sweat in 20 healthy volunteers following mild exercise. The concentration of aluminium ranged from 329 to 5329μg/L. These data equate to a daily excretion of between 234 and 7192μg aluminium and they strongly suggest that perspiration is the major route of excretion of systemic aluminium in humans. Copyright © 2013 Elsevier GmbH. All rights reserved.

  9. Window structure for passivating solar cells based on gallium arsenide

    Science.gov (United States)

    Barnett, Allen M. (Inventor)

    1985-01-01

    Passivated gallium arsenide solar photovoltaic cells with high resistance to moisture and oxygen are provided by means of a gallium arsenide phosphide window graded through its thickness from arsenic rich to phosphorus rich.

  10. Human exposure to aluminium.

    Science.gov (United States)

    Exley, Christopher

    2013-10-01

    Human activities have circumvented the efficient geochemical cycling of aluminium within the lithosphere and therewith opened a door, which was previously only ajar, onto the biotic cycle to instigate and promote the accumulation of aluminium in biota and especially humans. Neither these relatively recent activities nor the entry of aluminium into the living cycle are showing any signs of abating and it is thus now imperative that we understand as fully as possible how humans are exposed to aluminium and the future consequences of a burgeoning exposure and body burden. The aluminium age is upon us and there is now an urgent need to understand how to live safely and effectively with aluminium.

  11. Development of a Multi-layer Anti-reflective Coating for Gallium Arsenide/Aluminum Gallium Arsenide Solar Cells

    Science.gov (United States)

    2015-07-01

    Aluminum Gallium Arsenide Solar Cells by Kimberley A Olver Approved for public release; distribution unlimited...Development of a Multi-layer Anti-reflective Coating for Gallium Arsenide / Aluminum Gallium Arsenide Solar Cells by Kimberley A Olver... Aluminum Gallium Arsenide (AlGaAs) Solar Cells 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Kimberley A Olver

  12. Spin Injection in Indium Arsenide

    Directory of Open Access Journals (Sweden)

    Mark eJohnson

    2015-08-01

    Full Text Available In a two dimensional electron system (2DES, coherent spin precession of a ballistic spin polarized current, controlled by the Rashba spin orbit interaction, is a remarkable phenomenon that’s been observed only recently. Datta and Das predicted this precession would manifest as an oscillation in the source-drain conductance of the channel in a spin-injected field effect transistor (Spin FET. The indium arsenide single quantum well materials system has proven to be ideal for experimental confirmation. The 2DES carriers have high mobility, low sheet resistance, and high spin orbit interaction. Techniques for electrical injection and detection of spin polarized carriers were developed over the last two decades. Adapting the proposed Spin FET to the Johnson-Silsbee nonlocal geometry was a key to the first experimental demonstration of gate voltage controlled coherent spin precession. More recently, a new technique measured the oscillation as a function of channel length. This article gives an overview of the experimental phenomenology of the spin injection technique. We then review details of the application of the technique to InAs single quantum well (SQW devices. The effective magnetic field associated with Rashba spin-orbit coupling is described, and a heuristic model of coherent spin precession is presented. The two successful empirical demonstrations of the Datta Das conductance oscillation are then described and discussed.

  13. Graphene on gallium arsenide: Engineering the visibility

    OpenAIRE

    Friedemann, M.; Pierz, K.; Stosch, R.; Ahlers, F. J.

    2009-01-01

    Graphene consists of single or few layers of crystalline ordered carbon atoms. Its visibility on oxidized silicon (Si/SiO\\_2) enabled its discovery and spawned numerous studies of its unique electronic properties. The combination of graphene with the equally unique electronic material gallium arsenide (GaAs) has up to now lacked such easy visibility. Here we demonstrate that a deliberately tailored GaAs/AlAs (aluminum arsenide) multi-layer structure makes graphene just as visible on GaAs as o...

  14. Radiation damage of gallium arsenide production cells

    Science.gov (United States)

    Mardesich, N.; Joslin, D.; Garlick, J.; Lillington, D.; Gillanders, M.; Cavicchi, B.; Scott-Monck, J.; Kachare, R.; Anspaugh, B.

    1987-01-01

    High efficiency liquid phase epitaxy (LPE) gallium arsenide cells were irradiated with 1 Mev electrons up to fluences of 1 times 10 to the 16th power cm-2. Measurements of spectral response and dark and illuminated I-V data were made at each fluence and then, using computer codes, the experimental data was fitted to gallium arsenide cell models. In this way it was possible to determine the extent of the damage, and hence damage coefficients in both the emitter and base of the cell.

  15. Rows of Dislocation Loops in Aluminium Irradiated by Aluminium Ions

    DEFF Research Database (Denmark)

    Henriksen, L.; Johansen, A.; Koch, J.

    1967-01-01

    Single-crystal aluminium specimens, irradiated with 50-keV aluminium ions, contain dislocation loops that are arranged in regular rows along <110 > directions. ©1967 The American Institute of Physics......Single-crystal aluminium specimens, irradiated with 50-keV aluminium ions, contain dislocation loops that are arranged in regular rows along directions. ©1967 The American Institute of Physics...

  16. Design and fabrication of a gallium arsenide composite operational amplifier

    OpenAIRE

    Carson, David B.

    1995-01-01

    Silicon (Si) processes remain the dominant technology in integrated circuit (IC) design, but gallium arsenide (GaAs) is gaining ground. Gallium arsenide's electron mobility is five times greater than Si, so GaGs circuits are faster and have a greater rang U.S. Navy (U.S.N.) author.

  17. Superlattice Intermediate Band Solar Cell on Gallium Arsenide

    Science.gov (United States)

    2015-02-09

    AFRL-RV-PS- AFRL-RV-PS- TR-2015-0048 TR-2015-0048 SUPERLATTICE INTERMEDIATE BAND SOLAR CELL ON GALLIUM ARSENIDE Alexandre Freundlich...SUBTITLE 5a. CONTRACT NUMBER FA9453-13-1-0232 Superlattice Intermediate Band Solar Cell on Gallium Arsenide 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER

  18. Phosphorus enhances aluminium tolerance in both aluminium ...

    African Journals Online (AJOL)

    Seedlings growing in acid soils suffer both phosphorus (P) deficiency and aluminium (Al) toxicity stresses. An experiment was conducted to study the effects of Al and P interaction on Al-tolerant (ET8) and Al-sensitive (ES8) wheat genotypes in an acid soil. This study aimed to determine the interactive effect of Al and P in soil ...

  19. Development of gallium arsenide solar cells

    Science.gov (United States)

    1973-01-01

    The potential of ion implantation as a means to the development of high efficiency gallium arsenide solar cells is investigated. Summaries are included of the results of computer calculations of GaAs cell characteristics, based on a model which includes the effects of surface recombination, junction space-charge region recombination, and built-in fields produced by nonuniform doping in the region; of the fabrication technology developed under the program; and of the results of electrical and optical measurements on the samples produced during the program. It was determined that measured AMO efficiencies were more than a factor of two lower than the calculated values.

  20. Bragg Reflector-Induced Increased Nonradiative Lifetime in Gallium Arsenide (GaAs)/Aluminum Gallium Arsenide (AlGaAs) Double Heterostructures

    Science.gov (United States)

    2015-09-01

    GaAs)/ Aluminum Gallium Arsenide (AlGaAs) Double Heterostructures by Patrick A Folkes, Blair Connelly, Harry Hier, William Beck, and Brenda Van...Lifetime in Gallium Arsenide (GaAs)/ Aluminum Gallium Arsenide (AlGaAs) Double Heterostructures by Patrick A Folkes, Blair Connelly, Harry Hier...3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Bragg Reflector-Induced Increased Nonradiative Lifetime in Gallium Arsenide (GaAs)/ Aluminum

  1. Modelling of the modulation properties of arsenide and nitride VCSELs

    Science.gov (United States)

    Wasiak, Michał; Śpiewak, Patrycja; Moser, Philip; Gebski, Marcin; Schmeckebier, Holger; Sarzała, Robert P.; Lott, James A.

    2017-02-01

    In this paper, using our model of capacitance in vertical-cavity surface-emitting lasers (VCSELs), we analyze certain differences between an oxide-confined arsenide VCSEL emitting in the NIR region, and a nitride VCSEL emitting violet radiation. In the nitride laser its high differential resistance, caused partially by the low conductivity of p-type GaN material and the bottom contact configuration, is one of the main reasons why the nitride VCSEL has much worse modulation properties than the arsenide VCSEL. Using the complicated arsenide structure, we also analyze different possible ways of constructing the laser's equivalent circuit.

  2. Combined isovalent alloying gallium arsenide with bismuth and indium

    International Nuclear Information System (INIS)

    Vorob'eva, V.V.; Zushinskaya, O.V.; Novikov, S.V.; Savel'ev, I.G.; Chaldyshev, V.V.

    1989-01-01

    Electric conductivity and the Hall effect at 77 and 300K of gallium arsenide epitaxial films grown from the melted solution with bismuth and indium additions at 77 and 300K. Different mechanisms of bismuth and indium effect on the ensamble of defects and background addition in gallium arsenide, are established. Bismuth effect is conditioned by the change of liquid phase properties, and indium effect is conditioned by the processes taking place in a crystal. The experimental results have shown that the mutual alloying of gallium arsenide with indium and bismuth in the process of liquid-phase epitaxy ensures high electrophysical film properties

  3. Ion nitriding of aluminium

    International Nuclear Information System (INIS)

    Fitz, T.

    2002-09-01

    The present study is devoted to the investigation of the mechanism of aluminium nitriding by a technique that employs implantation of low-energy nitrogen ions and diffusional transport of atoms. The nitriding of aluminium is investigated, because this is a method for surface modification of aluminium and has a potential for application in a broad spectrum of fields such as automobile, marine, aviation, space technologies, etc. However, at present nitriding of aluminium does not find any large scale industrial application, due to problems in the formation of stoichiometric aluminium nitride layers with a sufficient thickness and good quality. For the purposes of this study, ion nitriding is chosen, as an ion beam method with the advantage of good and independent control over the process parameters, which thus can be related uniquely to the physical properties of the resulting layers. Moreover, ion nitriding has a close similarity to plasma nitriding and plasma immersion ion implantation, which are methods with a potential for industrial application. (orig.)

  4. Computer simulation of radiation damage in gallium arsenide

    Science.gov (United States)

    Stith, John J.; Davenport, James C.; Copeland, Randolph L.

    1989-01-01

    A version of the binary-collision simulation code MARLOWE was used to study the spatial characteristics of radiation damage in proton and electron irradiated gallium arsenide. Comparisons made with the experimental results proved to be encouraging.

  5. Optical Parametric Oscillation in Orientation-Patterned Gallium Arsenide

    National Research Council Canada - National Science Library

    Shell, Scott A

    2007-01-01

    .... Orientation patterned gallium arsenide (OPGaAs) is a promising nonlinear conversion material because it has broad transparency and can be engineered for specific pump laser and output wavelengths using quasi-phase matching techniques...

  6. Optical Characterization of Thick Growth Orientation-Patterned Gallium Arsenide

    National Research Council Canada - National Science Library

    Meyer, Joshua W

    2006-01-01

    .... Orientation patterned gallium arsenide (OPGaAs) is a promising nonlinear conversion material because it has broad transparency and can be engineered for specific pump laser and output wavelengths using quasi-phase matching techniques...

  7. Aluminium in Fisch und Fischereierzeugnissen

    OpenAIRE

    Ranau, Reiner; Oehlenschläger, Jörg

    1997-01-01

    Recent reports associating aluminium with several skeletal (osteomalacia) and neurological disorders (encephalopathy and Alzheimer’s disease) in humans suggest that exposure to aluminium may pose a hazard to health. This requires the examination of aluminiumcontent in different foodstuffs. Therefore, an analytical method for the determination of aluminium in fish and fishery products, especially in fishery products packaged in aluminium cans, was developed using graphite furnace atomic absorp...

  8. Recovery in aluminium

    DEFF Research Database (Denmark)

    Gundlach, Carsten

    2006-01-01

    In the present thesis the development of a unique experimental method for volume characterisation of individual embedded crystallites down to a radius of 150 nm is presented. This method is applied to in-situ studies of recovery in aluminium. The method is an extension of 3DXRD microscopy, an X...... by the combined use of X-ray micro focusing optics, new scanning algorithms and the use of foils. The ratio of foil thickness to crystallite size should be at least 10 such that the central ones are situated in a bulk environment. To avoid thermal drifts, gold reference markers are deposited onto the sample...... are represented as strings. To identify the strings a combination of a 5D connected component type algorithm and multi-peak fitting was found to be superior. The first use of the method was a study of recovery of a deformed aluminium alloy (AA1050). The aluminium alloy was deformed by cold rolling to a thickness...

  9. Method of fabricating germanium and gallium arsenide devices

    Science.gov (United States)

    Jhabvala, Murzban (Inventor)

    1990-01-01

    A method of semiconductor diode fabrication is disclosed which relies on the epitaxial growth of a precisely doped thickness layer of gallium arsenide or germanium on a semi-insulating or intrinsic substrate, respectively, of gallium arsenide or germanium by either molecular beam epitaxy (MBE) or by metal-organic chemical vapor deposition (MOCVD). The method involves: depositing a layer of doped or undoped silicon dioxide on a germanium or gallium arsenide wafer or substrate, selectively removing the silicon dioxide layer to define one or more surface regions for a device to be fabricated thereon, growing a matched epitaxial layer of doped germanium or gallium arsenide of an appropriate thickness using MBE or MOCVD techniques on both the silicon dioxide layer and the defined one or more regions; and etching the silicon dioxide and the epitaxial material on top of the silicon dioxide to leave a matched epitaxial layer of germanium or gallium arsenide on the germanium or gallium arsenide substrate, respectively, and upon which a field effect device can thereafter be formed.

  10. Contact formation in gallium arsenide solar cells

    Science.gov (United States)

    Weizer, Victor G.; Fatemi, Navid S.

    1988-01-01

    Gold and gold-based alloys, commonly used as solar cell contact materials, are known to react readily with gallium arsenide. Experiments were performed to identify the mechanisms involved in these GaAs-metal interactions. It is shown that the reaction of GaAs with gold takes place via a dissociative diffusion process. It is shown further that the GaAs-metal reaction rate is controlled to a very great extent by the condition of the free surface of the contact metal, an interesting example of which is the previously unexplained increase in the reaction rate that has been observed for samples annealed in a vacuum environment as compared to those annealed in a gaseous ambient. A number of other hard-to-explain observations, such as the low-temperature formation of voids in the gold lattice and crystallite growth on the gold surface, are explained by invoking this mechanism.

  11. Gallium Arsenide solar cell radiation damage experiment

    Science.gov (United States)

    Maurer, R. H.; Kinnison, J. D.; Herbert, G. A.; Meulenberg, A.

    1991-01-01

    Gallium arsenide (GaAs) solar cells for space applications from three different manufactures were irradiated with 10 MeV protons or 1 MeV electrons. The electrical performance of the cells was measured at several fluence levels and compared. Silicon cells were included for reference and comparison. All the GaAs cell types performed similarly throughout the testing and showed a 36 to 56 percent power areal density advantage over the silicon cells. Thinner (8-mil versus 12-mil) GaAs cells provide a significant weight reduction. The use of germanium (Ge) substrates to improve mechanical integrity can be implemented with little impact on end of life performance in a radiation environment.

  12. Surface magnetism of gallium arsenide nanofilms

    Science.gov (United States)

    Lu, Huan; Yu, Jin; Guo, Wanlin

    2017-11-01

    Gallium arsenide (GaAs) is the most widely used second-generation semiconductor with a direct band gap, and it is being increasingly used as nanofilms. However, the magnetic properties of GaAs nanofilms have never been studied. Here we find by comprehensive density-functional-theory calculations that GaAs nanofilms cleaved along the 〈111 〉 and 〈100 〉 directions become intrinsically metallic films with strong surface magnetism and the magnetoelectric effect. Surface magnetism and electrical conductivity are realized via a combined effect of charge transfer induced by spontaneous electric polarization through the film thickness and spin-polarized surface states. The surface magnetism of 〈111 〉 nanofilms can be significantly and linearly tuned by a vertically applied electric field, endowing the nanofilms with unexpectedly high magnetoelectric coefficients, which are tens of times higher than those of ferromagnetic metals and transition-metal oxides.

  13. The interaction of gold with gallium arsenide

    Science.gov (United States)

    Weizer, Victor G.; Fatemi, Navid S.

    1988-01-01

    Gold and gold-based alloys, commonly used as solar-cell contact materials, are known to react readily with gallium arsenide. Experiments designed to identify the mechanisms involved in these GaAs-metal interactions have yielded several interesting results. It is shown that the reaction of GaAs with gold takes place via a dissociative diffusion process. It is shown further that the GaAs-metal reaction rate is controlled to a very great extent by the condition of the free surface of the contact metal, an interesting example of which is the previously unexplained increase in the reaction rate that has been observed for samples annealed in a vacuum environment as compared to those annealed in a gaseous ambient. A number of other hard-to-explain observations, such as the low-temperature formation of voids in the gold lattice and crystallite growth on the gold surface, are also explained by invoking this mechanism.

  14. Fire exposed aluminium structures

    NARCIS (Netherlands)

    Maljaars, J.; Fellinger, J.; Soetens, F.

    2005-01-01

    Material properties and mechanical response models for fire design of steel structures are based on extensive research and experience. Contrarily, the behaviour of aluminium load bearing structures exposed to fire is relatively unexplored. This article gives an overview of physical and mechanical

  15. Fire exposed aluminium structures

    NARCIS (Netherlands)

    Maljaars, J.; Fellinger, J.H.H.; Soetens, F.

    2006-01-01

    Material properties and mechanical response models for fire design of steel structures are based on extensive research and experience. Contrarily, the behaviour of aluminium load bearing structures exposed to fire is relatively unexplored. This article gives an overview of physical and mechanical

  16. Activation Analysis of Aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Brune, Dag

    1961-01-15

    An analysis of pure aluminium alloyed with magnesium was per- formed by means of gamma spectrometry , Chemical separations were not employed. The isotopes to be determined were obtained in conditions of optimum activity by suitably choosing the time of irradiation and decay. The following elements were detected and measured quantitatively: Iron, zinc, copper, gallium, manganese, chromium, scandium and hafnium.

  17. Superconductor-semiconductor-superconductor planar junctions of aluminium on DELTA-doped gallium arsenide

    DEFF Research Database (Denmark)

    Taboryski, Rafael Jozef; Clausen, Thomas; Kutchinsky, jonatan

    1997-01-01

    We have fabricated and characterized planar superconductor-semiconductor-superconductor (S-Sm-S) junctions with a high quality (i.e. low barrier) interface between an n++ modulation doped conduction layer in MBE grown GaAs and in situ deposited Al electrodes. The Schottky barrier at the S-Sm inte...

  18. Studies on deep electronic levels in silicon and aluminium gallium arsenide alloys

    International Nuclear Information System (INIS)

    Pettersson, H.

    1993-01-01

    This thesis reports on investigations of the electrical and optical properties of deep impurity centers, related to the transition metals (TMs) Ti, Mo, W, V and Ni, in silicon. Emission rates, capture cross sections and photoionization cross sections for these impurities were determined by means of various Junction Space Charge Techniques (JSCTs), such as Deep Level Transient Spectroscopy (DLTS), dark capacitance transient and photo capacitance transient techniques. Changes in Gibbs free energy as a function of temperature were calculated for all levels. From this temperature dependence, the changes in enthalpy and entropy involved in the electron and hole transitions were deduced. The influence of high electric fields on the electronic levels in chalcogen-doped silicon were investigated using the dark capacitance transient technique. The enhancement of the electron emission from the deep centers indicated a more complex field enhancement model than the expected Poole-Frenkel effect for coulombic potentials. The possibility to determine charge states of defects using the Poole-Frenkel effect, as often suggested, is therefore questioned. The observation of a persistent decrease of the dark conductivity due to illumination in simplified AlGaAs/GaAs high Electron Mobility Transistors (HEMTs) over the temperature range 170K< T<300K is reported. A model for this peculiar behavior, based on the recombination of electrons in the two-dimensional electron gas (2DEG) located at the AlGaAs/GaAs interface with holes generated by a two-step excitation process via the deep EL2 center in the GaAs epilayer, is put forward

  19. Pure silver ohmic contacts to N- and P- type gallium arsenide materials

    Science.gov (United States)

    Hogan, Stephen J.

    1986-01-01

    Disclosed is an improved process for manufacturing gallium arsenide semiconductor devices having as its components an n-type gallium arsenide substrate layer and a p-type gallium arsenide diffused layer. The improved process comprises forming a pure silver ohmic contact to both the diffused layer and the substrate layer, wherein the n-type layer comprises a substantially low doping carrier concentration.

  20. Inhalation developmental toxicology studies: Gallium arsenide in mice and rats

    Energy Technology Data Exchange (ETDEWEB)

    Mast, T.J.; Greenspan, B.J.; Dill, J.A.; Stoney, K.H.; Evanoff, J.J.; Rommereim, R.L.

    1990-12-01

    Gallium arsenide is a crystalline compound used extensively in the semiconductor industry. Workers preparing solar cells and gallium arsenide ingots and wafers are potentially at risk from the inhalation of gallium arsenide dust. The potential for gallium arsenide to cause developmental toxicity was assessed in Sprague- Dawley rats and CD-1 (Swiss) mice exposed to 0, 10, 37, or 75 mg/m{sup 3} gallium arsenide, 6 h/day, 7 days/week. Each of the four treatment groups consisted of 10 virgin females (for comparison), and {approx}30 positively mated rats or {approx}24 positively mated mice. Mice were exposed on 4--17 days of gestation (dg), and rats on 4--19 dg. The day of plug or sperm detection was designated as 0 dg. Body weights were obtained throughout the study period, and uterine and fetal body weights were obtained at sacrifice (rats, 20 dg; mice, 18 dg). Implants were enumerated and their status recorded. Live fetuses were sexed and examined for gross, visceral, skeletal, and soft-tissue craniofacial defects. Gallium and arsenic concentrations were determined in the maternal blood and uterine contents of the rats (3/group) at 7, 14, and 20 dg. 37 refs., 11 figs., 30 tabs.

  1. Thermal stability of gallium arsenide solar cells

    Science.gov (United States)

    Papež, Nikola; Škvarenina, Ľubomír.; Tofel, Pavel; Sobola, Dinara

    2017-12-01

    This article summarizes a measurement of gallium arsenide (GaAs) solar cells during their thermal processing. These solar cells compared to standard silicon cells have better efficiency and high thermal stability. However, their use is partly limited due to high acquisition costs. For these reasons, GaAs cells are deployed only in the most demanding applications where their features are needed, such as space applications. In this work, GaAs solar cells were studied in a high temperature range within 30-650 °C where their functionality and changes in surface topology were monitored. These changes were recorded using an electron microscope which determined the position of the defects; using an atomic force microscope we determined the roughness of the surface and an infrared camera that showed us the thermal radiated places of the defected parts of the cell. The electrical characteristics of the cells during processing were determined by its current-voltage characteristics. Despite the occurrence of subtle changes on the solar cell with newly created surface features after 300 °C thermal processing, its current-voltage characteristic remained without a significant change.

  2. Evaluation of the carcinogenicity of gallium arsenide.

    Science.gov (United States)

    Bomhard, Ernst M; Gelbke, Heinz-Peter; Schenk, Hermann; Williams, Gary M; Cohen, Samuel M

    2013-05-01

    Gallium arsenide (GaAs) is an important semiconductor material. In 2-year inhalation studies, GaAs increased the incidence of lung tumors in female rats, but not in male rats or male and female mice. Alveolar proteinosis followed by chronic active inflammation was the predominant non-neoplastic pulmonary findings. IARC classified GaAs as carcinogenic to humans (group 1) based on the assumption that As and Ga ions are bioavailable. The European Chemical Agency Risk Assessment Committee concluded that GaAs should be classified into Carcinogenicity Category 1B (presumed to have carcinogenic potential for humans; ECHA). We evaluate whether these classifications are justified. Physico-chemical properties of GaAs particles and the degree of mechanical treatment are critical in this evaluation. The available data on mode of action (MOA), genotoxicity and bioavailability do not support the contribution of As or Ga ions to the lung tumors in female rats. Most toxicological studies utilized small particles produced by strong mechanical treatment, destroying the crystalline structure. The resulting amorphous GaAs is not relevant to crystalline GaAs at production and processing sites. The likely tumorigenic MOA is lung toxicity related to particulate-induced inflammation and increased proliferation. It is concluded that there is no evidence for a primary carcinogenic effect of GaAs.

  3. Maskless proton beam writing in gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Mistry, P. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom) and Nano-Electronics Centre, Advanced Technology Institute, University of Surrey, Guildford GU2 7XH (United Kingdom)]. E-mail: p.mistry@surrey.ac.uk; Gomez-Morilla, I. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Smith, R.C. [Nano-Electronics Centre, Advanced Technology Institute, University of Surrey, Guildford GU2 7XH (United Kingdom); Thomson, D. [Advanced Technology Institute, University of Surrey, Guildford GU2 7XH (United Kingdom); Grime, G.W. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Webb, R.P. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Gwilliam, R. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Jeynes, C. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Cansell, A. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Merchant, M. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Kirkby, K.J. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2007-07-15

    Proton beam writing (PBW) is a direct write technique that employs a focused MeV proton beam which is scanned in a pre-determined pattern over a target material which is subsequently electrochemically etched or chemically developed. By changing the energy of the protons the range of the protons can be changed. The ultimate depth of the structure is determined by the range of the protons in the material and this allows structures to be formed to different depths. PBW has been successfully employed on etchable glasses, polymers and semiconductor materials such as silicon (Si) and gallium arsenide (GaAs). This study reports on PBW in p-type GaAs and compares experimental results with computer simulations using the Atlas (copy right) semiconductor device package from SILVACO. It has already been proven that hole transport is required for the electrochemical etching of GaAs using Tiron (4,5-dihydroxy-m-benzenedisulfonic acid, di-sodium salt). PBW in GaAs results in carrier removal in the irradiated regions and consequently minimal hole transport (in these regions) during electrochemical etching. As a result the irradiated regions are significantly more etch resistant than the non-irradiated regions. This allows high aspect ratio structures to be formed.

  4. Maskless proton beam writing in gallium arsenide

    International Nuclear Information System (INIS)

    Mistry, P.; Gomez-Morilla, I.; Smith, R.C.; Thomson, D.; Grime, G.W.; Webb, R.P.; Gwilliam, R.; Jeynes, C.; Cansell, A.; Merchant, M.; Kirkby, K.J.

    2007-01-01

    Proton beam writing (PBW) is a direct write technique that employs a focused MeV proton beam which is scanned in a pre-determined pattern over a target material which is subsequently electrochemically etched or chemically developed. By changing the energy of the protons the range of the protons can be changed. The ultimate depth of the structure is determined by the range of the protons in the material and this allows structures to be formed to different depths. PBW has been successfully employed on etchable glasses, polymers and semiconductor materials such as silicon (Si) and gallium arsenide (GaAs). This study reports on PBW in p-type GaAs and compares experimental results with computer simulations using the Atlas (copy right) semiconductor device package from SILVACO. It has already been proven that hole transport is required for the electrochemical etching of GaAs using Tiron (4,5-dihydroxy-m-benzenedisulfonic acid, di-sodium salt). PBW in GaAs results in carrier removal in the irradiated regions and consequently minimal hole transport (in these regions) during electrochemical etching. As a result the irradiated regions are significantly more etch resistant than the non-irradiated regions. This allows high aspect ratio structures to be formed

  5. Roll bonding of strained aluminium

    DEFF Research Database (Denmark)

    Staun, Jakob M.

    2003-01-01

    This report investigates roll bonding of pre-strained (å ~ 4) aluminium sheets to produce high strain material from high purity aluminium (99.996%) and commercial pure aluminium (99.6%). The degree of bonding is investigated by optical microscopy and ultrasonic scanning. Under the right...... of the cross rolled volume fraction is found. To further asses this effect, and the anisotropy, it is necessary to acquire knowledge about both texture and microstructure, e.g. by TEM. Roll bonding of pre-strained aluminium is found to be a possible alternative to ARB in the quest for ultra-fine grained...

  6. Gallium arsenide processing for gate array logic

    Science.gov (United States)

    Cole, Eric D.

    1989-01-01

    The development of a reliable and reproducible GaAs process was initiated for applications in gate array logic. Gallium Arsenide is an extremely important material for high speed electronic applications in both digital and analog circuits since its electron mobility is 3 to 5 times that of silicon, this allows for faster switching times for devices fabricated with it. Unfortunately GaAs is an extremely difficult material to process with respect to silicon and since it includes the arsenic component GaAs can be quite dangerous (toxic) especially during some heating steps. The first stage of the research was directed at developing a simple process to produce GaAs MESFETs. The MESFET (MEtal Semiconductor Field Effect Transistor) is the most useful, practical and simple active device which can be fabricated in GaAs. It utilizes an ohmic source and drain contact separated by a Schottky gate. The gate width is typically a few microns. Several process steps were required to produce a good working device including ion implantation, photolithography, thermal annealing, and metal deposition. A process was designed to reduce the total number of steps to a minimum so as to reduce possible errors. The first run produced no good devices. The problem occurred during an aluminum etch step while defining the gate contacts. It was found that the chemical etchant attacked the GaAs causing trenching and subsequent severing of the active gate region from the rest of the device. Thus all devices appeared as open circuits. This problem is being corrected and since it was the last step in the process correction should be successful. The second planned stage involves the circuit assembly of the discrete MESFETs into logic gates for test and analysis. Finally the third stage is to incorporate the designed process with the tested circuit in a layout that would produce the gate array as a GaAs integrated circuit.

  7. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Straalen, IJ.J. van

    2004-01-01

    Traffic bridges are subjected to variable loads and should therefore be checked on fatigue. Especially low weight materials, like aluminium, are sensitive to fatigue, because the variable load is a substantial part of the total load. This paper shows the structural design of an aluminium bridge

  8. Advanced shipbuilding in aluminium

    International Nuclear Information System (INIS)

    Larsson, H.; Svensson, L.E.; Karlsson, L.

    1997-01-01

    The applicability of two different welding techniques for welding ships in aluminium is discussed. Conventional MIG welding and the recently developed Friction Super Stir Welding (FSSW) are compared concerning weld metal microstructures and mechanical properties. Results from testing of FSSW welds are also presented. It was observed that the grain size was smaller in FSSW welds are also presented. It was observed that the grain size was smaller in FSSW welds than in MIG welds whereas precipitates generally were larger in FSSW welds. The two methods produced welds with comparable mechanical properties. Good fatigue behaviour was obtained for FSSW welds. Advantages of the welding methods are also discussed. (Author) 7 refs

  9. Electrooptic Waveguide Directional Coupler Modulator in Aluminum Gallium Arsenide-Gallium Arsenide.

    Science.gov (United States)

    Khan, Mujibun Nisa

    A novel optical waveguide intensity modulator in aluminum gallium arsenide and gallium arsenide material system is modeled, designed, and experimentally demonstrated at 0.83 μm wavelength. The modulator utilizes the linear electrooptic effect in a coupled waveguide structure to achieve high extinction ratio at low drive voltage. The device structure consists of a differentially -etched ridge directional coupler, where the ridge height in the gap is smaller that that of the outer sides. The effective index and semivectorial finite difference modeling techniques are developed to analyze the single ridge guides and directional coupler structures. The mode structure results from the two models are compared and the limitations of the effective index method are determined. The differential -etch design is employed to reduce the length as well as the drive voltage of the modulator. A modulation voltage of 2 volts for a 3.5-mm-long device is achieved, which is the lowest reported in literature. These results are compared with those obtained from the simplified analytical expressions for conventional couplers, and higher performance expected from the differential-etch design is verified. The modulator extinction ratio is measured to be 13 dB at 2 volts. The measured optical propagation loss of approximately 3.4 dB/cm for the modulator is speculated to be primarily due to the surface morphology of the epitaxially-grown material, and the light scattering from rough ridge walls produced during the anisotropic dry etching process. The high microwave loss of 15 dB/cm calculated for the modulator electrode design suggests a trade-off between the modulation voltage and the bandwidth, which is expected to be limited to 500 MHz. The measurement of the modulator frequency response up to 100 KHz is presented, because of the test limitations at higher frequencies due to the weak modulated intensity signals.

  10. Rutherford backscatter measurements on tellurium and cadmium implanted gallium arsenide

    International Nuclear Information System (INIS)

    Bell, E.C.

    1979-10-01

    The primary aim of the work described in this thesis was to examine implanted layers of the dopant impurities cadmium and tellurium in gallium arsenide and to experimentally assess their potential for producing electrically active layers. 1.5 MeV Rutherford backscattering measurements of lattice disorder and atom site location have been used to assess post implantation thermal annealing and elevated temperature implantations to site the dopant impurities on either gallium or arsenic lattice positions in an otherwise undisordered lattice. Pyrolitically deposited silicon dioxide was used as an encapsulant to prevent thermal dissociation of the gallium arsenide during annealing. It has been shown that high doses of cadmium and tellurium can be implanted without forming amorphous lattice disorder by heating the gallium arsenide during implantation to relatively low temperatures. Atom site location measurements have shown that a large fraction of a tellurium dose implanted at 180 0 C is located on or near lattice sites. Channeled backscatter measurements have shown that there is residual disorder or lattice strain in gallium arsenide implanted at elevated temperatures. The extent of this disorder has been shown to depend on the implanted dose and implantation temperature. The channeling effect has been used to measure annealing of the disorder. (author)

  11. Thermal processes in gallium arsenide during nanosecond laser irradiation

    International Nuclear Information System (INIS)

    Ivlev, G.D.; Malevich, V.L.

    1990-01-01

    Phase changes in the surface layers of semiconductors during irradiation by nanosecond laser pulses have been the subject of large numbers of papers. The authors have performed numerical modeling and an experimental study of phase changes in the surface layers of single crystal gallium arsenide heated by single pulses of ruby laser light

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

    International Nuclear Information System (INIS)

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

    1991-11-01

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

  13. Aluminium in Drinkwater: voorkomen, herkomst en gezondheidsaspecten

    NARCIS (Netherlands)

    Versteegh JFM; de Boer JLM; van den Velde-Koerts T

    1992-01-01

    Aluminium can occur in drinking water because of the application of aluminium salts as a coagulant in the treatment of drinking water. In the Netherlands mostly iron salts are used instead of aluminium. Besides this aluminium can be present in the source for drinking water. In shallow groundwater

  14. Direct electrodeposition of aluminium nano-rods

    OpenAIRE

    Perre, Emilie; Nyholm, Leif; Gustafsson, Torbjörn; Taberna, Pierre-Louis; Simon, Patrice; Edström, Kristina

    2008-01-01

    Electrodeposition of aluminium within an alumina nano-structured template, for use as high surface area current collectors in Li-ion microbatteries, was investigated. The aluminium electrodeposition was carried out in the ionic liquid 1-ethyl-3-methylimidazolium chloride:aluminium chloride (1:2 ratio). First the aluminium electrodeposition process was confirmed by combined cyclic voltammetry and electrochemical quartz crystal microbalance measurements. Then, aluminium was electrodeposit...

  15. Aluminium in Drinkwater: voorkomen, herkomst en gezondheidsaspecten

    OpenAIRE

    Versteegh JFM; de Boer JLM; van den Velde-Koerts T

    1992-01-01

    Aluminium can occur in drinking water because of the application of aluminium salts as a coagulant in the treatment of drinking water. In the Netherlands mostly iron salts are used instead of aluminium. Besides this aluminium can be present in the source for drinking water. In shallow groundwater high levels have been found probably related to acidification, which is an environmental problem. Aluminium can cause neurological diseases in patients who are on chronic haemodialysis because of ren...

  16. Performance Comparison of Top and Bottom Contact Gallium Arsenide (GaAs) Solar Cell

    Science.gov (United States)

    2014-09-01

    Performance Comparison of Top and Bottom Contact Gallium Arsenide (GaAs) Solar Cell by Naresh C Das ARL-TR-7054 September 2014...September 2014 Performance Comparison of Top and Bottom Contact Gallium Arsenide (GaAs) Solar Cell Naresh C Das Sensors and Electron...From - To) 01/02/2014–07/15/2014 4. TITLE AND SUBTITLE Performance Comparison of Top and Bottom Contact Gallium Arsenide (GaAs) Solar Cell 5a

  17. Running droplets of gallium from evaporation of gallium arsenide.

    Science.gov (United States)

    Tersoff, J; Jesson, D E; Tang, W X

    2009-04-10

    High-temperature annealing of gallium arsenide in vacuum causes excess evaporation of arsenic, with accumulation of gallium as liquid droplets on the surface. Using real-time in situ surface electron microscopy, we found that these droplets spontaneously run across the crystal surface. Running droplets have been seen in many systems, but they typically require special surface preparation or gradient forces. In contrast, we show that noncongruent evaporation automatically provides a driving force for running droplets. The motion is predicted and observed to slow and stop near a characteristic temperature, with the speed increasing both below and above this temperature. The same behavior is expected to occur during the evaporation of similar III-V semiconductors such as indium arsenide.

  18. Two-photon photovoltaic effect in gallium arsenide.

    Science.gov (United States)

    Ma, Jichi; Chiles, Jeff; Sharma, Yagya D; Krishna, Sanjay; Fathpour, Sasan

    2014-09-15

    The two-photon photovoltaic effect is demonstrated in gallium arsenide at 976 and 1550 nm wavelengths. A waveguide-photodiode biased in its fourth quadrant harvests electrical power from the optical energy lost to two-photon absorption. The experimental results are in good agreement with simulations based on nonlinear wave propagation in waveguides and the drift-diffusion model of carrier transport in semiconductors. Power efficiency of up to 8% is theoretically predicted in optimized devices.

  19. Assessment of arsenic exposures and controls in gallium arsenide production.

    Science.gov (United States)

    Sheehy, J W; Jones, J H

    1993-02-01

    The electronics industry is expanding the use of gallium arsenide in the production of optoelectronic devices and integrated circuits. Workers in the electronics industry using gallium arsenide are exposed to hazardous substances such as arsenic, arsine, and various acids. Arsenic requires stringent controls to minimize exposures (the current OSHA PEL for arsenic is 10 micrograms/m3 and the NIOSH REL is 2 micrograms/m3 ceiling). Inorganic arsenic is strongly implicated in respiratory tract and skin cancer. For these reasons, NIOSH researchers conducted a study of control systems for facilities using gallium arsenide. Seven walk-through surveys were performed to identify locations for detailed study which appeared to have effective controls; three facilities were chosen for in-depth evaluation. The controls were evaluated by industrial hygiene sampling. Including personal breathing zone and area air sampling for arsenic and arsine; wipe samples for arsenic also were collected. Work practices and the use of personal protective equipment were documented. This paper reports on the controls and the arsenic exposure results from the evaluation of the following gallium arsenide processes: Liquid Encapsulated Czochralski (LEC) and Horizontal Bridgeman (HB) crystal growing, LEC cleaning operations, ingot grinding/wafer sawing, and epitaxy. Results at one plant showed that in all processes except epitaxy, average arsenic exposures were at or above the OSHA action level of 5 micrograms/m3. While cleaning the LEC crystal pullers, the average potential arsenic exposure of the cleaning operators was 100 times the OSHA PEL. At the other two plants, personal exposures for arsenic were well controlled in LEC, LEC cleaning, grinding/sawing, and epitaxy operations.

  20. Alloys of uranium and aluminium with low aluminium content

    International Nuclear Information System (INIS)

    Cabane, G.; Englander, M.; Lehmann, J.

    1955-01-01

    Uranium, as obtained after spinning in phase γ, presents an heterogeneous structure with large size grains. The anisotropic structure of the metal leads to an important buckling and surface distortion of the fuel slug which is incompatible with its tubular cladding for nuclear fuel uses. Different treatments have been made to obtain an isotropic structure presenting high thermal stability (laminating, hammering and spinning in phase α) without success. Alloys of uranium and aluminium with low aluminium content present important advantage in respect of non allied uranium. The introduction of aluminium in the form of intermetallic compound (UAl 2 ) gives a better resistance to thermal fatigue. Alloys obtained from raw casting present an improved buckling and surface distortion in respect of pure uranium. This improvement is obtained with uranium containing between 0,15 and 0,5 % of aluminium. An even more improvement in thermal stability is obtained by thermal treatments of these alloys. These new characteristics are explained by the fine dispersion of the UAl 2 particles in uranium. The results after treatments obtained from an alloy slug containing 0,4 % of aluminium show no buckling or surface distortion and no elongation. (M.P.)

  1. Effect of hydrogen on aluminium and aluminium alloys: A review

    DEFF Research Database (Denmark)

    Ambat, Rajan; Dwarakadasa, E.S.

    1996-01-01

    Susceptibility of aluminium and its alloys towards hydrogen embrittlement has been well established. Still a lot of confusion exists on the question of transport of hydrogen and its possible role in stress corrosion cracking. This paper reviews some of the fundamental properties of hydrogen...... in aluminium and its alloys and its effect on mechanical properties. The importance of hydrogen embrittlement over anodic dissolution to explain the stress corrosion cracking mechanism of these alloys is also examined in considerable detail. The various experimental findings concerning the link between...... hydrogen embrittlement and stress corrosion cracking are also discussed....

  2. Gallium arsenide differentially affects processing of phagolysosomal targeted antigen by macrophages.

    Science.gov (United States)

    Lewis, T A; Hartmann, C B; McCoy, K L

    1998-03-01

    Gallium arsenide, a semiconductor utilized in the electronics industry, causes immunosuppression in animals. The chemical's effect on macrophages to process antigen for activating pigeon cytochrome-specific helper T cell hybridoma was investigated. Mice were administered 200 mg/kg gallium arsenide or vehicle intraperitoneally. Five-day exposure suppressed processing by splenic macrophages but augmented processing by thioglycollate-elicited and resident peritoneal macrophages. Cytochrome coupled to latex beads was targeted to phagolysosomes to examine processing in lysosomes. Cytochrome beads required phagocytosis for processing and were located in phagolysosomes. Gallium arsenide did not alter the phagocytic ability of macrophages. Peritoneal macrophages normally processed the targeted antigen, indicating that gallium arsenide influenced compartment(s) preceding lysosomes. However, the processing efficiency of exposed splenic macrophages depended on the size of particulate cytochrome, suggesting that processing varied in phagolysosomes of different sizes. Gallium arsenide impacted different intracellular compartments in these macrophages, perhaps contributing to systemic immunotoxicity and local inflammation caused by exposure.

  3. Design and analysis of aluminium brdiges

    NARCIS (Netherlands)

    Soetens, F.; Straalen, IJ.J. van

    2004-01-01

    Applications of aluminium have grown considerably in building and civil engineering the last decade, which is due to various aspects: light weight, durability and maintenance, use of extrusions. The paper starts with a short history of aluminium bridges and then focuses on aluminium bridges in the

  4. Buckwheat stomatal traits under aluminium toxicity

    Directory of Open Access Journals (Sweden)

    Oleksandr E. Smirnov

    2014-04-01

    Full Text Available Aluminium influence on some stomatal parameters of common buckwheat (Fagopyrum esculentum Moench. was studied. Significant changes in stomatal density, stomatal index and stomatal shape coefficient under aluminium treatment were revealed. Stomatal closure and no difference in total stomatal potential conductance index of treatment plants were suggested as aluminium resistance characteristics.

  5. Does Aluminium Trigger Breast Cancer?

    Directory of Open Access Journals (Sweden)

    Peter Jennrich

    2016-08-01

    Full Text Available Summary. Breast cancer is by far the most common cancer in women in the western world. In 90% of breast cancers, environmental factors are among the causes. The frequency with which the tumour occurs in the outer upper part of the breast has risen with above average rates in recent decades. Aluminium salts as ingredients in deodorants and antiperspirants are being absorbed by the body to a greater extent than hitherto assumed. Their toxicity for healthy and diseased breast tissue cells includes various well-documented pathomechanisms. In the sense of primary and secondary prevention, the cancer-triggering potential of aluminium and its use in anti-perspirant deodorants must be re-evaluated. For the same reason the access to a targeted diagnosis and treatment of aluminium loading must be facilitated.

  6. Aluminium phosphide-induced leukopenia.

    Science.gov (United States)

    Ntelios, Dimitrios; Mandros, Charalampos; Potolidis, Evangelos; Fanourgiakis, Panagiotis

    2013-10-30

    Acute intoxication from the pesticide aluminium phosphide is a relatively rare, life-threatening condition in which cardiovascular decompensation is the most feared problem. We report the case of a patient exposed to aluminium phosphide-liberated phosphine gas. It resulted in the development of a gastroenteritis-like syndrome accompanied by severe reduction in white blood cell numbers as an early and prominent manifestation. By affecting important physiological processes such as mitochondrial function and reactive oxygen species homeostasis, phosphine could cause severe toxicity. After presenting the characteristics of certain leucocyte subpopulations we provide the current molecular understanding of the observed leukopenia which in part seems paradoxical.

  7. Laser and electron beam processing of silicon and gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, J.

    1979-10-01

    Laser (photon) and electron beams provide a controlled source of heat by which surface layers of silicon and gallium arsenide can be rapidly melted and cooled with rates exceeding 10/sup 80/C/sec. The melting process has been used to remove displacement damage in ion implanted Si and GaAs, to remove dislocations, loops and precipitates in silicon and to study impurity segregation and solubility limits. The mechanisms associated with various phenomena will be examined. The possible impact of laser and electron beam processing on device technology, particularly with respect to solar cells is discussed.

  8. Improved performance design of gallium arsenide solar cells for space

    Science.gov (United States)

    Parekh, R. H.; Barnett, A. M.

    1984-01-01

    An improved design, shallow junction heteroface, n-p, gallium arsenide solar cell for space applications is reported, with a predicted AM0 efficiency in the 21.9 to 23.0 percent range. The optimized n-p structure, while slightly more efficient, has the added advantage of being less susceptible to radiation-induced degradation by virtue of this thin top junction layer. Detailed spectral response curves and an analysis of the loss mechanisms are reported. The details of the design are readily measurable. The optimized designs were reached by quantifying the dominant loss mechanisms and then minimizing them by using computer simulations.

  9. Testing of gallium arsenide solar cells on the CRRES vehicle

    Science.gov (United States)

    Trumble, T. M.

    1985-01-01

    A flight experiment was designed to determine the optimum design for gallium arsenide (GaAs) solar cell panels in a radiation environment. Elements of the experiment design include, different coverglass material and thicknesses, welded and soldered interconnects, different solar cell efficiencies, different solar cell types, and measurement of annealing properties. This experiment is scheduled to fly on the Combined Release and Radiation Effects Satellite (CRRES). This satellite will simultaneously measure the radiation environment and provide engineering data on solar cell degradation that can be directly related to radiation damage.

  10. Liquid phase epitaxy of gallium arsenide - a review

    International Nuclear Information System (INIS)

    Alexiev, D.; Edmondson, M.; Butcher, K.S.A.; Tansley, T.

    1992-07-01

    Liquid phase epitaxy of gallium arsenide has been investigated intensively from the late 1960's to the present and has now a special place in the manufacture of wide band, compound semiconductor radiation detectors. Although this particular process appears to have gained prominence in the last three decades, the authors point out that its origins reach back to 1836 when Frankenheim made his first observations. A brief review is presented from a semiconductor applications point of view on how this subject developed. 70 refs., 5 figs

  11. Anomalous tensoelectric effects in gallium arsenide tunnel diodes

    Energy Technology Data Exchange (ETDEWEB)

    Alekseeva, Z.M.; Vyatkin, A.P.; Krivorotov, N.P.; Shchegol' , A.A.

    1988-02-01

    Anomalous tensoelectric phenomena induced in a tunnel p-n junction by a concentrated load and by hydrostatic compression were studied. The anomalous tensoelectric effects are caused by the action of concentrators of mechanical stresses in the vicinity of the p-n junction, giving rise to local microplastic strain. Under the conditions of hydrostatic compression prolate inclusions approx.100-200 A long play the role of concentrators. Analysis of irreversible changes in the current-voltage characteristics of tunnel p-n junctions made it possible to separate the energy levels of the defects produced with plastic strain of gallium arsenide.

  12. Testing of gallium arsenide solar cells on the CRRES vehicle

    International Nuclear Information System (INIS)

    Trumble, T.M.

    1985-01-01

    A flight experiment was designed to determine the optimum design for gallium arsenide (GaAs) solar cell panels in a radiation environment. Elements of the experiment design include, different coverglass material and thicknesses, welded and soldered interconnects, different solar cell efficiencies, different solar cell types, and measurement of annealing properties. This experiment is scheduled to fly on the Combined Release and Radiation Effects Satellite (CRRES). This satellite will simultaneously measure the radiation environment and provide engineering data on solar cell degradation that can be directly related to radiation damage

  13. Ca4As3 – a new binary calcium arsenide

    Science.gov (United States)

    Hoffmann, Andrea V.; Hlukhyy, Viktor; Fässler, Thomas F.

    2015-01-01

    The crystal structure of the binary compound tetra­calcium triarsenide, Ca4As3, was investigated by single-crystal X-ray diffraction. Ca4As3 crystallizes in the Ba4P3 structure type and is thus a homologue of isotypic Sr4As3. The unit cell contains 32 Ca2+ cations, 16 As3− isolated anions and four centrosymmetric [As2]4– dumbbells. The As atoms in each of the dumbbells are connected by a single bond, thus this calcium arsenide is a Zintl phase. PMID:26870427

  14. Ca4As3 – a new binary calcium arsenide

    Directory of Open Access Journals (Sweden)

    Andrea V. Hoffmann

    2015-12-01

    Full Text Available The crystal structure of the binary compound tetracalcium triarsenide, Ca4As3, was investigated by single-crystal X-ray diffraction. Ca4As3 crystallizes in the Ba4P3 structure type and is thus a homologue of isotypic Sr4As3. The unit cell contains 32 Ca2+ cations, 16 As3− isolated anions and four centrosymmetric [As2]4– dumbbells. The As atoms in each of the dumbbells are connected by a single bond, thus this calcium arsenide is a Zintl phase.

  15. Effect of Bio char on Plant Growth and Aluminium Form of Soil under Aluminium Stress

    Science.gov (United States)

    Qian, Lianwen; Li, Qingbiao; Sun, Jingwei; Feng, Ying

    2018-01-01

    Aluminium-enriched acid red soils in South China easily cause aluminium toxicity to plants, but biochip can improve soils and eliminate soil contaminations. In this project, biochip was used in potted plant control test to study the effect of biochip on plant growth in soil under acid aluminium stress and the migration and conversion of aluminium in plant-soil system. The fin dings show that the application of biochip increases the pH value of soil under aluminium stress significantly, changes the existing form of aluminium ion in soil, reduces the plants’ absorption of aluminium, and alleviates the aluminium toxicity to plants, but too much biochip may inhibit the growth of plants. In this case, further study should be carried out as regards the volume and way of biochip input in practical applications as well as the timeliness of aluminium toxicity removal.

  16. Constitutive modelling of aluminium foams

    NARCIS (Netherlands)

    Wang, W.M.; Lemmen, P.P.M.

    2001-01-01

    In this paper an aluminium foam model is proposed for a vehicle crash analysis. The model assumes that there is no coupling between stresses and strains in different principal directions. The stress in each principle direction is then interpolated from an experimental recorded uniaxial stress strain

  17. Recovery mechanisms in nanostructured aluminium

    DEFF Research Database (Denmark)

    Yu, Tianbo; Hansen, Niels; Huang, Xiaoxu

    2012-01-01

    Commercial purity aluminium (99.5%) has been cold rolled to a true strain of 5.5 (99.6% reduction in thickness). The material is very strong but low temperature recovery may be a limiting factor. This has been investigated by isothermal annealing treatments in the temperature range 5–100C. Hardness...

  18. Lattice parameters guide superconductivity in iron-arsenides

    International Nuclear Information System (INIS)

    Konzen, Lance M N; Sefat, Athena S

    2017-01-01

    The discovery of superconducting materials has led to their use in technological marvels such as magnetic-field sensors in MRI machines, powerful research magnets, short transmission cables, and high-speed trains. Despite such applications, the uses of superconductors are not widespread because they function much below room-temperature, hence the costly cooling. Since the discovery of Cu- and Fe-based high-temperature superconductors (HTS), much intense effort has tried to explain and understand the superconducting phenomenon. While no exact explanations are given, several trends are reported in relation to the materials basis in magnetism and spin excitations. In fact, most HTS have antiferromagnetic undoped ‘parent’ materials that undergo a superconducting transition upon small chemical substitutions in them. As it is currently unclear which ‘dopants’ can favor superconductivity, this manuscript investigates crystal structure changes upon chemical substitutions, to find clues in lattice parameters for the superconducting occurrence. We review the chemical substitution effects on the crystal lattice of iron-arsenide-based crystals (2008 to present). We note that (a) HTS compounds have nearly tetragonal structures with a -lattice parameter close to 4 Å, and (b) superconductivity can depend strongly on the c -lattice parameter changes with chemical substitution. For example, a decrease in c -lattice parameter is required to induce ‘in-plane’ superconductivity. The review of lattice parameter trends in iron-arsenides presented here should guide synthesis of new materials and provoke theoretical input, giving clues for HTS. (topical review)

  19. Point defects and electric compensation in gallium arsenide single crystals

    International Nuclear Information System (INIS)

    Kretzer, Ulrich

    2007-01-01

    In the present thesis the point-defect budget of gallium arsenide single crystals with different dopings is studied. It is shown, in which way the concentration of the single point defects depende on the concentration of the dopants, the stoichiometry deviation, and the position of the Fermi level. For this serve the results of the measurement-technical characterization of a large number of samples, in the fabrication of which these parameters were directedly varied. The main topic of this thesis lies in the development of models, which allow a quantitative description of the experimentally studied electrical and optical properties of gallium arsenide single crystals starting from the point-defect concentrations. Because from point defects charge carriers can be set free, their concentration determines essentially the charge-carrier concentration in the bands. In the ionized state point defects act as scattering centers for free charge carriers and influence by this the drift mobility of the charge carriers. A thermodynamic modeling of the point-defect formation yields statements on the equilibrium concentrations of the point defects in dependence on dopant concentration and stoichiometry deviation. It is show that the electrical properties of the crystals observed at room temperature result from the kinetic suppression of processes, via which the adjustment of a thermodynamic equilibrium between the point defects is mediated [de

  20. Macroscopic diffusion models for precipitation in crystalline gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Kimmerle, Sven-Joachim Wolfgang

    2009-09-21

    Based on a thermodynamically consistent model for precipitation in gallium arsenide crystals including surface tension and bulk stresses by Dreyer and Duderstadt, we propose two different mathematical models to describe the size evolution of liquid droplets in a crystalline solid. The first model treats the diffusion-controlled regime of interface motion, while the second model is concerned with the interface-controlled regime of interface motion. Our models take care of conservation of mass and substance. These models generalise the well-known Mullins- Sekerka model for Ostwald ripening. We concentrate on arsenic-rich liquid spherical droplets in a gallium arsenide crystal. Droplets can shrink or grow with time but the centres of droplets remain fixed. The liquid is assumed to be homogeneous in space. Due to different scales for typical distances between droplets and typical radii of liquid droplets we can derive formally so-called mean field models. For a model in the diffusion-controlled regime we prove this limit by homogenisation techniques under plausible assumptions. These mean field models generalise the Lifshitz-Slyozov-Wagner model, which can be derived from the Mullins-Sekerka model rigorously, and is well understood. Mean field models capture the main properties of our system and are well adapted for numerics and further analysis. We determine possible equilibria and discuss their stability. Numerical evidence suggests in which case which one of the two regimes might be appropriate to the experimental situation. (orig.)

  1. Evaluation of the male reproductive toxicity of gallium arsenide.

    Science.gov (United States)

    Bomhard, Ernst M; Cohen, Samuel M; Gelbke, Heinz-Peter; Williams, Gary M

    2012-10-01

    Gallium arsenide is an important semiconductor material marketed in the shape of wafers and thus is not hazardous to the end user. Exposure to GaAs particles may, however, occur during manufacture and processing. Potential hazards require evaluation. In 14-week inhalation studies with small GaAs particles, testicular effects have been reported in rats and mice. These effects occurred only in animals whose lungs showed marked inflammation and also had hematologic changes indicating anemia and hemolysis. The time- and concentration-dependent progressive nature of the lung and blood effects together with bioavailability data on gallium and arsenic lead us to conclude that the testicular/sperm effects are secondary to hypoxemia resulting from lung damage rather than due to a direct chemical effect of gallium or arsenide. Conditions leading to such primary effects are not expected to occur in humans at production and processing sites. This has to be taken into consideration for any classification decision for reproductive toxicity; especially a category 1 according to the EU CLP system is not warranted. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Bumblebee pupae contain high levels of aluminium.

    Science.gov (United States)

    Exley, Christopher; Rotheray, Ellen; Goulson, David

    2015-01-01

    The causes of declines in bees and other pollinators remains an on-going debate. While recent attention has focussed upon pesticides, other environmental pollutants have largely been ignored. Aluminium is the most significant environmental contaminant of recent times and we speculated that it could be a factor in pollinator decline. Herein we have measured the content of aluminium in bumblebee pupae taken from naturally foraging colonies in the UK. Individual pupae were acid-digested in a microwave oven and their aluminium content determined using transversely heated graphite furnace atomic absorption spectrometry. Pupae were heavily contaminated with aluminium giving values between 13.4 and 193.4 μg/g dry wt. and a mean (SD) value of 51.0 (33.0) μg/g dry wt. for the 72 pupae tested. Mean aluminium content was shown to be a significant negative predictor of average pupal weight in colonies. While no other statistically significant relationships were found relating aluminium to bee or colony health, the actual content of aluminium in pupae are extremely high and demonstrate significant exposure to aluminium. Bees rely heavily on cognitive function and aluminium is a known neurotoxin with links, for example, to Alzheimer's disease in humans. The significant contamination of bumblebee pupae by aluminium raises the intriguing spectre of cognitive dysfunction playing a role in their population decline.

  3. Friction Welding of Aluminium and Aluminium Alloys with Steel

    Directory of Open Access Journals (Sweden)

    Andrzej Ambroziak

    2014-01-01

    Full Text Available The paper presents our actual knowledge and experience in joining dissimilar materials with the use of friction welding method. The joints of aluminium and aluminium alloys with the different types of steel were studied. The structural effects occurring during the welding process were described. The mechanical properties using, for example, (i microhardness measurements, (ii tensile tests, (iii bending tests, and (iv shearing tests were determined. In order to obtain high-quality joints the influence of different configurations of the process such as (i changing the geometry of bonding surface, (ii using the interlayer, or (iii heat treatment was analyzed. Finally, the issues related to the selection of optimal parameters of friction welding process were also investigated.

  4. Partial molar volumes of aluminium chloride, aluminium sulphate and aluminium nitrate in water-rich binary aqueous mixtures of tetrahydrofuran

    OpenAIRE

    R. C. Thakur; Ravi Sharma; Ashish Kumar; Sanjay Kumar; M. L. Parmar

    2014-01-01

    Partial molar volumes of aluminium chloride, aluminium sulphate and aluminium nitrate have been determined in water rich binary aqueous mixtures of tetrahydrofuran (5, 10, 15, 20% by weight of tetrahydrofuran) with the help of density measurements. The density measurements were made by using Ward and Millero method and results have been analysed by Masson’s equation and interpreted in terms of ion-ion or ion –solvent interactions. The partial molar volumes vary with temperature as a power ser...

  5. Effects of low-energy gallium-aluminum-arsenide laser irradiation on cultured fibroblasts and keratinocytes.

    Science.gov (United States)

    Pogrel, M A; Chen, J W; Zhang, K

    1997-01-01

    To assess whether the gallium-aluminum-arsenide low energy laser will increase cell proliferation, cell attachment, or cell migration in cultured fibroblasts and keratinocyte models. Monolayer cultures of fibroblasts and keratinocytes were subjected to gallium-aluminum-arsenide laser irradiation at varying power densities for varying time intervals. Cell proliferation was assessed by absorbent spectrophotometry while cell adhesion was assessed by a microcolorimetric assay for cells attached to bovine dermis collagen. Cell migration was assessed through a filter utilizing high power microscopic fields. There were no differences in cell proliferation, adhesion, or migration in either the fibroblasts or keratinocyte culture treated with the gallium-aluminum-arsenide laser at any power density or time compared with nontreated controls. The gallium-aluminum-arsenide laser, when utilized at powers 5-100 milliwatts and times of between 10-120 seconds has no biostimulatory effects on fibroblasts or keratinocyte cultures as assessed by cell proliferation, adhesion, or migration.

  6. Deposition and characterization of gallium arsenide films for solar cells applications

    Science.gov (United States)

    Chu, S. S.; Chu, T. L.; Lee, Y. T.

    1980-04-01

    Gallium arsenide films have been deposited on tungsten-coated graphite substrates by the reaction of gallium, hydrogen chloride, and arsine in a hydrogen flow. It has been found that the presence of hydrogen chloride in the gallium monochloride-arsenic mixture is essential in obtaining large-area gallium arsenide films with sufficiently good microstructure suitable for photovoltaic devices. Schottky-barrier and MOS structures have been prepared from n-GaAs/n(+)-GaAs films on tungsten/graphite substrates, and their electrical properties investigated. Under AM1 conditions, MOS structures of area 9 sq cm have conversion efficiencies of up to 4.4 percent (without antireflection (AR) coating, would be about 6.7 percent with proper coating), and the conversion efficiencies can be increased to 5 percent (without AR coating, would be about 7.5 percent with proper coating) by using a thin gallium arsenide-phosphide film at the surface of gallium arsenide.

  7. PREPARATION AND PROPERTIES OF ALUMINIUM COMPOSITE

    OpenAIRE

    T. Albert*, C. Pravin Tamil Selvan

    2017-01-01

    A composite material is the combination of two or more materials, which are having different phases and the properties superior to the base material. Aluminium matrix composite (AMCs) are emerging as advance engineering materials due to their strength, ductility and toughness. The aluminium matrix can strengthened by reinforcing with hard ceramic particles like SiC, Al2o3 , B4C etc. In this paper, an effort is made to enhance the mechanical properties like strength and hardness of aluminium ...

  8. Surface treatments for aluminium alloys

    Science.gov (United States)

    Ardelean, M.; Lascău, S.; Ardelean, E.; Josan, A.

    2018-01-01

    Typically, in contact with the atmosphere, the aluminium surface is covered with an aluminium oxide layer, with a thickness of less than 1-2μm. Due to its low thickness, high porosity and low mechanical strength, this layer does not protect the metal from corrosion. Anodizing for protective and decorative purposes is the most common method of superficial oxidation processes and is carried out through anodic oxidation. The oxide films, resulted from anodizing, are porous, have a thickness of 20-50μm, and are heat-resistant, stable to water vapour and other corrosion agents. Hard anodizing complies with the same obtains principles as well as decorative and protective anodization. The difference is in that hard anodizing is achieved at low temperatures and high intensity of electric current. In the paper are presented the results of decorative and hard anodization for specimens made from several aluminium alloys in terms of the appearance of the specimens and of the thickness of the anodized.

  9. A biogeochemical cycle for aluminium?

    Science.gov (United States)

    Exley, Christopher

    2003-09-15

    The elaboration of biogeochemical cycles for elements which are known to be essential for life has enabled a broad appreciation of the homeostatic mechanisms which underlie element essentiality. In particular they can be used effectively to identify any part played by human activities in element cycling and to predict how such activities might impact upon the lithospheric and biospheric availability of an element in the future. The same criteria were the driving force behind the construction of a biogeochemical cycle for aluminium, a non-essential element which is a known ecotoxicant and a suspected health risk in humans. The purpose of this exercise was to examine the concept of a biogeochemical cycle for aluminium and not to review the biogeochemistry of this element. The cycle as presented is rudimentary and qualitative though, even in this nascent form, it is informative and predictive and, for these reasons alone, it is deserving of future quantification. A fully fledged biogeochemical cycle for aluminium should explain the biospheric abundance of this element and whether we should expect its (continued) active involvement in biochemical evolution.

  10. Toxicity of aluminium on five aquatic invertebrates; Aluminiums toksisitet paa 5 akvatiske invertebrater

    Energy Technology Data Exchange (ETDEWEB)

    Moe, J. [Oslo Univ. (Norway)

    1996-01-01

    The conference paper deals with the experiments done by investigating the effects from the toxicity of aluminium on aquatic invertebrates. The aim of the experiments was to compare the toxicity of unstable aluminium compounds with stable forms of aluminium. 8 refs., 2 figs., 2 tabs.

  11. Aluminium and nickel in human albumin solutions

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Sandberg, E

    1989-01-01

    Five different brands of commercially available human albumin solutions for infusion were analysed for their aluminium and nickel contents by atomic absorption spectrometry. The aluminium concentrations ranged from 12 micrograms/l to 1109 micrograms/l and the nickel concentrations ranged from 17...... micrograms/l to 77 micrograms/l. Examination of the aluminium and nickel contents of the constituents for the production of one brand showed too low levels to explain the final contamination of the product. By following the aluminium and nickel concentrations of the same brand during the production...

  12. Aluminium and nickel in human albumin solutions

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Sandberg, E

    1989-01-01

    Five different brands of commercially available human albumin solutions for infusion were analysed for their aluminium and nickel contents by atomic absorption spectrometry. The aluminium concentrations ranged from 12 micrograms/l to 1109 micrograms/l and the nickel concentrations ranged from 17...... of a batch of albumin solution, filtration was shown to contribute to contamination, although the largest increase in aluminium as well as nickel concentrations appeared during the bulk concentrating process. To avoid health risks to certain patients, regulations should be established requiring aluminium...

  13. First principles predictions of intrinsic defects in aluminum arsenide, AlAs : numerical supplement.

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, Peter Andrew

    2012-04-01

    This Report presents numerical tables summarizing properties of intrinsic defects in aluminum arsenide, AlAs, as computed by density functional theory. This Report serves as a numerical supplement to the results published in: P.A. Schultz, 'First principles predictions of intrinsic defects in Aluminum Arsenide, AlAs', Materials Research Society Symposia Proceedings 1370 (2011; SAND2011-2436C), and intended for use as reference tables for a defect physics package in device models.

  14. Bit-systolic arithmetic arrays using dynamic differential gallium arsenide circuits

    Science.gov (United States)

    Beagles, Grant; Winters, Kel; Eldin, A. G.

    1992-01-01

    A new family of gallium arsenide circuits for fine grained bit-systolic arithmetic arrays is introduced. This scheme combines features of two recent techniques of dynamic gallium arsenide FET logic and differential dynamic single-clock CMOS logic. The resulting circuits are fast and compact, with tightly constrained series FET propagation paths, low fanout, no dc power dissipation, and depletion FET implementation without level shifting diodes.

  15. Density Functional Theory Study on Defect Feature of AsGaGaAs in Gallium Arsenide

    Directory of Open Access Journals (Sweden)

    Deming Ma

    2015-01-01

    Full Text Available We investigate the defect feature of AsGaGaAs defect in gallium arsenide clusters in detail by using first-principles calculations based on the density functional theory (DFT. Our calculations reveal that the lowest donor level of AsGaGaAs defect on the gallium arsenide crystal surface is 0.85 eV below the conduction band minimum, while the lowest donor level of the AsGaGaAs defect inside the gallium arsenide bulk is 0.83 eV below the bottom of the conduction band, consistent with gallium arsenide EL2 defect level of experimental value (Ec-0.82 eV. This suggests that AsGaGaAs defect is one of the possible gallium arsenide EL2 deep-level defects. Moreover, our results also indicate that the formation energies of internal AsGaGaAs and surface AsGaGaAs defects are predicted to be around 2.36 eV and 5.54 eV, respectively. This implies that formation of AsGaGaAs defect within the crystal is easier than that of surface. Our results offer assistance in discussing the structure of gallium arsenide deep-level defect and its effect on the material.

  16. Temperature dependence of carrier capture by defects in gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Wampler, William R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Modine, Normand A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    This report examines the temperature dependence of the capture rate of carriers by defects in gallium arsenide and compares two previously published theoretical treatments of this based on multi phonon emission (MPE). The objective is to reduce uncertainty in atomistic simulations of gain degradation in III-V HBTs from neutron irradiation. A major source of uncertainty in those simulations is poor knowledge of carrier capture rates, whose values can differ by several orders of magnitude between various defect types. Most of this variation is due to different dependence on temperature, which is closely related to the relaxation of the defect structure that occurs as a result of the change in charge state of the defect. The uncertainty in capture rate can therefore be greatly reduced by better knowledge of the defect relaxation.

  17. Gallium arsenide/gold nanostructures deposited using plasma method

    Energy Technology Data Exchange (ETDEWEB)

    Mangla, O. [Department of Physics and Astrophysics, University of Delhi, Delhi, 110007 (India); Physics Department, Hindu College, University of Delhi, Delhi, 110007 (India); Roy, S. [Physics Department, Daulat Ram College, University of Delhi, Delhi, 110007, India. E-mail: savitaroy64@gmail.com (India); Annapoorni, S. [Department of Physics and Astrophysics, University of Delhi, Delhi, 110007 (India)

    2016-05-23

    The fabrication of gallium arsenide (GaAs) nanostructures on gold coated glass, quartz and silicon substrates using the high fluence and highly energetic ions has been reported. The high fluence and highly energetic ions are produced by the hot, dense and extremely non-equilibrium plasma in a modified dense plasma focus device. The nanostructures having mean size about 14 nm, 13 nm and 18 nm are deposited on gold coated glass, quartz and silicon substrates, respectively. The optical properties of nanostructures studied using absorption spectra show surface plasmon resonance peak of gold nanoparticles. In addition, the band-gap of GaAs nanoparticles is more than that of bulk GaAs suggesting potential applications in the field of optoelectronic and sensor systems.

  18. Aluminium in apple juice - no storing of fruit juice in aluminium tanks

    OpenAIRE

    German Federal Institute for Risk Assessment

    2017-01-01

    Elevated aluminium levels in fruit juice, particularly in apple juice, were measured by the official food control authorities. The cause was the incorrect storage of juice in aluminium containers that were not coated with varnish. As aluminium is dissolved by acid-containing and salt-containing food, the metal was able to migrate to the juice. In the case of short-term dietary intake, aluminium is scarcely harmful at all. In the case of elevated, long-term intake, aluminium can, howe...

  19. Effect of gallium-arsenide laser, gallium-aluminum-arsenide laser and healing ointment on cutaneous wound healing in Wistar rats

    OpenAIRE

    Gonçalves,R.V.; Mezêncio,J.M.S.; Benevides,G.P.; Matta,S.L.P.; Neves,C.A.; Sarandy,M.M.; Vilela,E.F.

    2010-01-01

    This study determined the effects of gallium-aluminum-arsenide laser (GaAlAs), gallium-arsenide laser (GaAs) and Dersani® healing ointment on skin wounds in Wistar rats. The parameters analyzed were: type I and III collagen fiber concentrations as well as the rate of wound closure. Five wounds, 12 mm in diameter, were made on the animals’ backs. The depth of the surgical incision was controlled by removing the epithelial tissue until the dorsal muscular fascia was exposed. The animals w...

  20. Aluminium Pneumoconiosis I. In Vitro Comparison of Stamped Aluminium Powders Containing Different Lubricating Agents and a Granular Aluminium Powder

    Science.gov (United States)

    Corrin, B.

    1963-01-01

    The discrepancy in previous reports of the action of aluminium on the lung may be explained by differences between stamped and granular aluminium powders. A stamped powder of the variety causing pulmonary fibrosis showed a brisk reaction with water, but a granular powder was unreactive. This difference is primarily due to the granular particles being covered by inert aluminium oxide, the formation of which is partially prevented in the stamping process by stearine and mineral oil. The reactivity of the flake-like stamped particles is also dependent on their large surface area per unit volume. The appearance of aluminium pneumoconiosis in Britain is explained by the introduction of mineral oil into the stamping industry for, in contrast to stearine, mineral oil permits the powder to react with water. The lung damage is believed to be caused by a soluble form of aluminium. PMID:14072616

  1. Rapidly solidified aluminium for optical applications

    NARCIS (Netherlands)

    Gubbels, G.P.H.; Venrooy, B.W.H. van; Bosch, A.J.; Senden, R.

    2008-01-01

    This paper present the results of a diamond turning study of a rapidly solidified aluminium 6061 alloy grade, known as RSA6061. It is shown that this small grain material can be diamond turned to smaller roughness values than standard AA6061 aluminium grades. Also, the results are nearly as good as

  2. Electron Conditioning of Technical Aluminium Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Le Pimpec, F

    2004-09-02

    The effect of electron conditioning on commercially aluminium alloys 1100 and 6063 were investigated. Contrary to the assumption that electron conditioning, if performed long enough, can reduce and stabilize the SEY to low values (= 1.3, value of many pure elements [1]), the SEY of aluminium did not go lower than 1.8. In fact, it reincreases with continued electron exposure dose.

  3. Thermal formation of corundum from aluminium hydroxides ...

    Indian Academy of Sciences (India)

    Abstract. Aluminium hydroxides have been precipitated from various aluminium salts and the differences in their thermal behaviour have been investigated. Pseudoboehmite derived from the nitrate, sulfate and chloride all form γ-Al2O3 at ~ 400°C but the formation of α-Al2O3 at 1200°C occurs more readily in the material ...

  4. Thermal formation of corundum from aluminium hydroxides ...

    Indian Academy of Sciences (India)

    Aluminium hydroxides have been precipitated from various aluminium salts and the differences in their thermal behaviour have been investigated. Pseudoboehmite derived from the nitrate, sulfate and chloride all form -Al2O3 at ∼ 400°C but the formation of -Al2O3 at 1200°C occurs more readily in the material derived ...

  5. Characterisation and concentration profile of aluminium during ...

    African Journals Online (AJOL)

    An aluminium(Al) characterisation study was conducted at a surface water treatment plant (Buffalo Pound Water Treatment Plant (BPWTP) in Moose Jaw, Saskatchewan, Canada) to understand better the effect of alum coagulant on various Al fractions. The raw water source for BPWTP is Buffalo Pound Lake water. The Al ...

  6. Lactobacillus plantarum CCFM639 alleviates aluminium toxicity.

    Science.gov (United States)

    Yu, Leilei; Zhai, Qixiao; Liu, Xiaoming; Wang, Gang; Zhang, Qiuxiang; Zhao, Jianxin; Narbad, Arjan; Zhang, Hao; Tian, Fengwei; Chen, Wei

    2016-02-01

    Aluminium (Al) is the most abundant metal in the earth's crust. Al exposure can cause a variety of adverse physiological effects in humans and animals. Our aim was to demonstrate that specific probiotic bacteria can play a special physiologically functional role in protection against Al toxicity in mice. Thirty strains of lactic acid bacteria (LAB) were tested for their aluminium-binding ability, aluminium tolerance, their antioxidative capacity, and their ability to survive the exposure to artificial gastrointestinal (GI) juices. Lactobacillus plantarum CCFM639 was selected for animal experiments because of its excellent performance in vitro. Forty mice were divided into four groups: control, Al only, Al plus CCFM639, and Al plus deferiprone (DFP). CCFM639 was administered at 10(9) CFU once daily for 10 days, followed by a single oral dose of aluminium chloride hexahydrate at 5.14 mg aluminium (LD50) for each mouse. The results showed that CCFM639 treatment led to a significant reduction in the mortality rates with corresponding decrease in intestinal aluminium absorption and in accumulation of aluminium in the tissues and amelioration of hepatic histopathological damage. This probiotic treatment also resulted in alleviation of hepatic, renal, and cerebral oxidative stress. The treatment of L. plantarum CCFM639 has potential as a therapeutic dietary strategy against acute aluminium toxicity.

  7. Behaviour of millscale reinforced Aluminium Bronze composite ...

    African Journals Online (AJOL)

    Despite the desirable characteristics exhibited by most aluminium bronze, the deficient responses in certain critical applications have necessitated improvement in the mechanical properties. The microstructural and mechanical properties of cast aluminium bronze reinforced with iron millscale particles were investigated in ...

  8. Acoustic properties of aluminium foams

    Directory of Open Access Journals (Sweden)

    García, L. E.

    2008-09-01

    Full Text Available The article discusses normal incidence sound absorption by aluminium foam manufactured with powder metallurgy technology. Aluminium foams with different surface morphologies were obtained by varying the type of precursor and adding filler materials during the foaming process. The sound absorption coefficients found for these aluminium foams were compared to the coefficient for commercial foams marketed under the name ALPORAS. The effect of foam thickness on the absorption coefficient was studied for each sample prepared. The combination of good acoustic and mechanical properties makes aluminium foams particularly attractive products. The study included an analysis of the effect of 2-, 5- and 10-cm air gaps on the sound absorption coefficient. The results showed that such gaps, which are routinely used in construction to reduce the reverberation period in indoor premises, raised the low frequency absorption coefficient significantly. This increase was found to depend on aluminium foam density and thickness and the depth of the air gap. In this same line, we have investigated the absorption coefficient of the aluminium foams combined with a mineral fiber panel.Se presenta un estudio del coeficiente de absorción acústica a incidencia normal de espumas de aluminio fabricadas mediante la técnica pulvimetalúrgica. Se fabricaron espumas de aluminio de distinta morfología superficial variando el tipo de precursor y usando materiales de relleno durante el proceso de espumación. Se muestra un estudio comparativo del coeficiente de absorción acústica de las espumas de aluminio fabricadas y las espumas comerciales conocidas como ALPORAS. Para cada muestra fabricada se estudió la influencia del espesor sobre el valor del coeficiente de absorción.El atractivo de las espumas de aluminio radica en que en ellas se combinan interesantes propiedades acústicas y mecánicas. Se analizó el efecto de una cámara de aire de 2, 5 y 10 cm de anchura sobre el

  9. Aluminium in foodstuff and the influence of aluminium foil used for food preparation or short time storage.

    Science.gov (United States)

    Ertl, Kathrin; Goessler, Walter

    2018-02-28

    Aluminium is an omnipresent part of everyday life. It is widely used in industry and furthermore in products like cosmetics, sun creams or it can be applied for instance as aluminium foil by consumers during food preparation in households. However, over the last decades the toxicity of aluminium for humans has been heavily discussed and is still not completely clarified. Therefore, food aluminium concentrations were investigated in different untreated foodstuff as well as a possible aluminium transfer from aluminium foil to food. The results show that untreated food is not significantly contaminated. Furthermore, short time contact to aluminium foil increases the food aluminium concentration only marginal. Nevertheless, as soon as the food is in contact to aluminium foil and at the same time in contact with metals (alloys) with a higher standard electrode potential than aluminium (-1.66 V) high aluminium contaminations were observed.

  10. Recent developments in advanced aircraft aluminium alloys

    International Nuclear Information System (INIS)

    Dursun, Tolga; Soutis, Costas

    2014-01-01

    Highlights: • To compete with composites, performance of aluminium alloys should be increased. • Al–Li alloys have higher strength, fracture and fatigue/corrosion resistance. • Improvements of aerospace Al alloys are due to optimised solute content and ratios. • In selecting new materials, there should be no reduction in the level of safety. • The use of hybrid materials could provide additional opportunities for Al alloys. - Abstract: Aluminium alloys have been the primary material for the structural parts of aircraft for more than 80 years because of their well known performance, well established design methods, manufacturing and reliable inspection techniques. Nearly for a decade composites have started to be used more widely in large commercial jet airliners for the fuselage, wing as well as other structural components in place of aluminium alloys due their high specific properties, reduced weight, fatigue performance and corrosion resistance. Although the increased use of composite materials reduced the role of aluminium up to some extent, high strength aluminium alloys remain important in airframe construction. Aluminium is a relatively low cost, light weight metal that can be heat treated and loaded to relatively high level of stresses, and it is one of the most easily produced of the high performance materials, which results in lower manufacturing and maintenance costs. There have been important recent advances in aluminium aircraft alloys that can effectively compete with modern composite materials. This study covers latest developments in enhanced mechanical properties of aluminium alloys, and high performance joining techniques. The mechanical properties on newly developed 2000, 7000 series aluminium alloys and new generation Al–Li alloys are compared with the traditional aluminium alloys. The advantages and disadvantages of the joining methods, laser beam welding and friction stir welding, are also discussed

  11. Design of Indium Arsenide nanowire sensors for pH and biological sensing and low temperature transport through p-doped Indium Arsenide nanowires

    DEFF Research Database (Denmark)

    Upadhyay, Shivendra

    remains the primary material of choice. This research is about investigating Indium Arsenide nanowires as alternative platform for sensing charged species - chemical and biological, in solution. Starting with nanowires grown via molecular beam epitaxy in an ultra-high vacuum chamber, we discuss...

  12. Shot peening of aluminium alloys

    International Nuclear Information System (INIS)

    Le Guernic, Y.

    1998-01-01

    Shot peening is a process of cold-hammering where a metallic surface is pelted with spherical grains. Each grain bumping into the surface acts as a hammer head and creates a small crater. The overlapping of these craters produces a residual compression layer just underneath the surface. It is well known that cracks cannot spread in a compression zone. In most cases of fatigue rupture and stress corrosion cracks propagate from the surface towards the inside so shot peening allows a longer lifetime of castings. Moreover most materials present a better resistance due to the cold-hammering effect of shot peening. Metallic surfaces can be treated in workshops or directly on site. Typical pieces that undergo shot peening on site are storing tanks, gas and steam turbines, tubes of steam generators and piping in oil or nuclear or chemical industries. This article describes shot peening from a theoretical and general point of view and presents the application to aluminium-lithium alloys. In the case of aluminium alloys shot peening can be used to shape the piece (peen-forming). (A.C.)

  13. Method for aluminium dross utilization

    International Nuclear Information System (INIS)

    Lucheva, B.; Petkov, R.; Tzonev, Tz.

    2003-01-01

    A new hydrometallurgical method has been developed for metal aluminum utilization from secondary aluminum dross. Secondary aluminum dross is a powder product with an average of 35% aluminium content (below 1mm). It is waste from primary aluminum dross pyrometallurgical flux less treatment in rotary DC electric arc furnace. This method is based on aluminum leaching in copper chloride water solution. As a result an aluminum oxychloride solution and solids, consisting of copper and oxides are obtained. In order to copper chloride solution regenerate hydrochloric acid is added to the solids. The process is simple, quick, economic and safe. The aluminum oxychloride solution contains 56 g/l Al 2 O 3 . The molar ratios are Al:Cl=0,5; OH:Al=1. The solution has 32 % basicity and 1,1 g/cm 3 density. For increasing the molar ratio of aluminium to chlorine aluminum hydroxide is added to this solution at 80 o C. Aluminum hydroxide is the final product from the secondary aluminum dross alkaline leaching. As a result aluminum oxychloride solution of the following composition is prepared: Al 2 O 3 - 180 g/l; Al:Cl=1,88; OH:Al=4,64; basicity 82%; density 1,22 g/cm 3 , pH=4 -4,5. Aluminum oxychloride solution produced by means of this method can be used in potable and wastewater treatment, paper making, in refractory mixture as a binder etc. (Original)

  14. Analysis tools for the design of aluminium extrusion dies

    NARCIS (Netherlands)

    Koopman, A.J.

    2009-01-01

    The aluminium extrusion process is a forming process where a billet of hot aluminium is pressed through a die to produce long straight aluminium profiles. A large variety of products with different and complex cross-sections can be made. The insight in the mechanics of the aluminium extrusion

  15. Alveolar proteinosis associated with aluminium dust inhalation.

    Science.gov (United States)

    Chew, R; Nigam, S; Sivakumaran, P

    2016-08-01

    Secondary alveolar proteinosis is a rare lung disease which may be triggered by a variety of inhaled particles. The diagnosis is made by detection of anti-granulocyte-macrophage colony-stimulating factor antibodies in bronchoalveolar lavage fluid, which appears milky white and contains lamellar bodies. Aluminium has been suggested as a possible cause, but there is little evidence in the literature to support this assertion. We report the case of a 46-year-old former boilermaker and boat builder who developed secondary alveolar proteinosis following sustained heavy aluminium exposure. The presence of aluminium was confirmed both by histological examination and metallurgical analysis of a mediastinal lymph node. Despite cessation of exposure to aluminium and treatment with whole-lung lavage which normally results in improvements in both symptoms and lung function, the outcome was poor and novel therapies are now being used for this patient. It may be that the natural history in aluminium-related alveolar proteinosis is different, with the metal playing a mediating role in the disease process. Our case further supports the link between aluminium and secondary alveolar proteinosis and highlights the need for measures to prevent excessive aluminium inhalation in relevant industries. © The Author 2016. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Epoxy coatings electrodeposited on aluminium and modified aluminium surfaces

    Directory of Open Access Journals (Sweden)

    Lazarević Zorica Ž.

    2002-01-01

    Full Text Available The corrosion behaviour and thermal stability of epoxy coatings electrodeposited on modified aluminum surfaces (anodized, phosphatized and chromatized-phosphatized aluminium were monitored during exposure to 3% NaCl solution, using electrochemical impedance spectroscopy (EIS and thermogravimetric analysis (TGA. Better protective properties of the epoxy coatings on anodized and chromatized-phosphatized aluminum with respect to the same epoxy coatings on aluminum and phosphatized aluminum were obtained: higher values of Rp and Rct and smaller values of Cc and Cd, from EIS, and a smaller amount of absorbed water inside the coating, from TGA. On the other hand, a somewhat lower thermal stability of these coatings was obtained (smaller values of the ipdt temperature. This behavior can be explained by the less porous structure of epoxy coatings on anodized and chromatized-phosphatized aluminum, caused by a lower rate of H2 evolution and better wet ability.

  17. Aluminium in Biological Environments: A Computational Approach

    Science.gov (United States)

    Mujika, Jon I; Rezabal, Elixabete; Mercero, Jose M; Ruipérez, Fernando; Costa, Dominique; Ugalde, Jesus M; Lopez, Xabier

    2014-01-01

    The increased availability of aluminium in biological environments, due to human intervention in the last century, raises concerns on the effects that this so far “excluded from biology” metal might have on living organisms. Consequently, the bioinorganic chemistry of aluminium has emerged as a very active field of research. This review will focus on our contributions to this field, based on computational studies that can yield an understanding of the aluminum biochemistry at a molecular level. Aluminium can interact and be stabilized in biological environments by complexing with both low molecular mass chelants and high molecular mass peptides. The speciation of the metal is, nonetheless, dictated by the hydrolytic species dominant in each case and which vary according to the pH condition of the medium. In blood, citrate and serum transferrin are identified as the main low molecular mass and high molecular mass molecules interacting with aluminium. The complexation of aluminium to citrate and the subsequent changes exerted on the deprotonation pathways of its tritable groups will be discussed along with the mechanisms for the intake and release of aluminium in serum transferrin at two pH conditions, physiological neutral and endosomatic acidic. Aluminium can substitute other metals, in particular magnesium, in protein buried sites and trigger conformational disorder and alteration of the protonation states of the protein's sidechains. A detailed account of the interaction of aluminium with proteic sidechains will be given. Finally, it will be described how alumnium can exert oxidative stress by stabilizing superoxide radicals either as mononuclear aluminium or clustered in boehmite. The possibility of promotion of Fenton reaction, and production of hydroxyl radicals will also be discussed. PMID:24757505

  18. Investigation of the aluminium-aluminium oxide reversible transformation as observed by hot stage electron microscopy.

    Science.gov (United States)

    Grove, C. A.; Judd, G.; Ansell, G. S.

    1972-01-01

    Thin foils of high purity aluminium and an Al-Al2O3 SAP type of alloy were oxidised in a specially designed hot stage specimen chamber in an electron microscope. Below 450 C, amorphous aluminium oxide formed on the foil surface and was first detectable at foil edges, holes, and pits. Islands of aluminium then nucleated in this amorphous oxide. The aluminium islands displayed either a lateral growth with eventual coalescence with other islands, or a reoxidation process which caused the islands to disappear. The aluminium island formation was determined to be related to the presence of the electron beam. A mechanism based upon electron charging due to the electron beam was proposed to explain the nucleation, growth, coalescence, disappearance, and geometry of the aluminium islands.

  19. Niobium-base grain refiner for aluminium

    International Nuclear Information System (INIS)

    Silva Pontes, P. da; Robert, M.H.; Cupini, N.L.

    1980-01-01

    A new chemical grain refiner for aluminium has been developed, using inoculation of a niobium-base compound. When a bath of molten aluminium is inoculated whith this refiner, an intermetallic aluminium-niobium compound is formed which acts as a powerful nucleant, producing extremely fine structure comparable to those obtained by means of the traditional grain refiner based on titanium and boron. It was found that the refinement of the structure depends upon the weight percentage of the new refiner inoculated as well as the time of holding the bath after inoculation and before pouring, but mainly on the inoculating temperature. (Author) [pt

  20. Synthesis of arsenic transition metal sulfides and metal arsenides

    Energy Technology Data Exchange (ETDEWEB)

    Singhal, G.H.; Brown, L.D.; Ryan, D.F. [Exxon Research & Development Labs, Baton Rouge, LA (United States)

    1993-12-31

    One of the chief problems in upgrading shale oil is the presence of inherent arsenic which is known to poison downstream catalysts. Highly dispersed transition metal sulfides formed in situ from the decomposition of dithiocarbamate (DTC) complexes of transition metals show excellent potential as dearsenation agents. The authors have studied the reaction of these sulfides with various arsenic compositions and characterized the metal arsenides and arsenic metal sulfides formed as well as the ease of their formation. Thus, the reaction of bis(butyldithiocarbamato)Ni, (NiBuDTC) with model compounds was very facile and gave NiAs, NiAsS, and NiAs2=xSx. In general the effectiveness of the sulfides for dearsenation followed the sequence Ni>Mo{much_gt}Co, while iron sulfides were totally ineffective. Based upon these results, tests were run in autoclaves (as well as a fixed-bed flow-through unit) with NiBuDTC and shale oil having 73 ppm inherent As. Under optimum conditions, dearsenation down to les than 1 ppm was obtained.

  1. Gallium arsenide (GaAs) quantum photonic waveguide circuits

    Science.gov (United States)

    Wang, Jianwei; Santamato, Alberto; Jiang, Pisu; Bonneau, Damien; Engin, Erman; Silverstone, Joshua W.; Lermer, Matthias; Beetz, Johannes; Kamp, Martin; Höfling, Sven; Tanner, Michael G.; Natarajan, Chandra M.; Hadfield, Robert H.; Dorenbos, Sander N.; Zwiller, Val; O'Brien, Jeremy L.; Thompson, Mark G.

    2014-09-01

    Integrated quantum photonics is a promising approach for future practical and large-scale quantum information processing technologies, with the prospect of on-chip generation, manipulation and measurement of complex quantum states of light. The gallium arsenide (GaAs) material system is a promising technology platform, and has already successfully demonstrated key components including waveguide integrated single-photon sources and integrated single-photon detectors. However, quantum circuits capable of manipulating quantum states of light have so far not been investigated in this material system. Here, we report GaAs photonic circuits for the manipulation of single-photon and two-photon states. Two-photon quantum interference with a visibility of 94.9±1.3% was observed in GaAs directional couplers. Classical and quantum interference fringes with visibilities of 98.6±1.3% and 84.4±1.5% respectively were demonstrated in Mach-Zehnder interferometers exploiting the electro-optic Pockels effect. This work paves the way for a fully integrated quantum technology platform based on the GaAs material system.

  2. Speed gallium arsenide photoconductors; Photoconducteurs rapides en arseniure de gallium

    Energy Technology Data Exchange (ETDEWEB)

    Foulon, F.; Pochet, T. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Electronique et d`Instrumentation Nucleaire; Brullot, B. [CEA Centre d`Etudes de Bruyeres-le-Chatel, 91 (France)

    1993-12-31

    Gallium arsenide detectors are one of the most efficient gamma and X ray detectors at room temperature. Due to the high carrier mobility and short carrier lifetime, GaAs can be used for the detection of ultrafast gamma, X or laser pulses. GaAs photoconductors allow both pulse shape and intensity measurements. In this paper, we review the results of studies carried out jointly by the CEA/LETI/DEIN and CEA/DAM/CEM in France to improve the response of such detectors. The geometry of the photodetectors and their electrical contacts have been optimized for specific radiation measurements: low energy X rays (< 1 KeV), gamma rays or protons. It has been shown that a pre-irradiation treatment with fission neutrons at doses above 10{sup 14} n/cm{sup 2} induces a significant improvement of the response speed. This result from defect generation in the material and the subsequent carrier life time decrease. Detectors with sensitivities of about 10{sup -8} A/R.s for gamma rays and 10{sup -16} coulomb/proton, response times below 100 ps and good linearity over more than five decades are currently fabricated in our laboratory. (authors). 18 refs., 5 figs., 3 tabs.

  3. Impact of in vitro gallium arsenide exposure on macrophages

    International Nuclear Information System (INIS)

    Harrison, M.Travis; Hartmann, Constance B.; McCoy, Kathleen L.

    2003-01-01

    The semiconductor gallium arsenide (GaAs) is classified as an immunotoxicant and a carcinogen. We previously showed that GaAs in vivo induces several phenotypic changes in macrophages located at the exposure site, indicative of an activated state. These physiological alterations may be a primary or secondary consequence of chemical exposure. To discern primary influences, our current study examined the in vitro effects of the chemical on macrophage cell lines and murine peritoneal macrophages. GaAs augmented cathepsins L and B proteolytic activities in all three sources of macrophages. Expression of the two mature isoforms of invariant chain and its cleavage fragment was also significantly increased, indicating that the chemical directly affects macrophages. However, GaAs did not alter the overall cell surface expression of major histocompatibility complex class II molecules on macrophages nor influence their ability to stimulate antigen-specific helper T cell hybridomas to respond to intact antigens that require processing. These findings raise the possibility that the chemical's complete in vivo impact may involve cytokines. Further, GaAs in vitro enhanced steady-state cathepsin L protein, and cathepsins L and B mRNA expression in macrophages, indicating that GaAs may alter gene expression, which may contribute to the chemical's adverse biological effects

  4. Gallium arsenide deep-level optical emitter for fibre optics.

    Science.gov (United States)

    Pan, Janet L; McManis, Joseph E; Osadchy, Thomas; Grober, Louise; Woodall, Jerry M; Kindlmann, Peter J

    2003-06-01

    Fibre-optic components fabricated on the same substrate as integrated circuits are important for future high-speed communications. One industry response has been the costly push to develop indium phosphide (InP) electronics. However, for fabrication simplicity, reliability and cost, gallium arsenide (GaAs) remains the established technology for integrated optoelectronics. Unfortunately, the GaAs bandgap wavelength (0.85 microm) is far too short for fibre optics at 1.3-1.5 microm. This has led to work on materials that have a large lattice mismatch on GaAs. Here we demonstrate the first light-emitting diode (LED) that emits at 1.5 microm fibre-optic wavelengths in GaAs using optical transitions from arsenic antisite (As(Ga)) deep levels. This is an enabling technology for fibre-optic components that are lattice-matched to GaAs integrated circuits. We present experimental results showing significant internal optical power (24 mW) and speed (in terahertz) from GaAs optical emitters using deep-level transitions. Finally, we present theory showing the ultimate limit to the efficiency-bandwidth product of semiconductor deep-level optical emitters.

  5. Deprotecting thioacetyl-terminated terphenyldithiol for assembly on gallium arsenide.

    Science.gov (United States)

    Krapchetov, Dmitry A; Ma, Hong; Jen, Alex K Y; Fischer, Daniel A; Loo, Yueh-Lin

    2008-02-05

    We characterize the assembly of terphenyldithiol (TPDT) on gallium arsenide (GaAs) from ethanol (EtOH) and tetrahydrofuran (THF) as a function of ammonium hydroxide (NH4OH) concentration. NH4OH facilitates the conversion of thioacetyl end groups of the TPDT precursor to thiolates in the assembly solution. The final structure of TPDT assembled on GaAs is sensitive not only to the assembly solvent but also to NH4OH concentration. In the presence of low concentrations of NH4OH (1 mM), TPDT assemblies from EtOH are oriented upright. The same assemblies are less upright when adsorption is carried out at higher NH4OH concentrations. In THF, TPDT does not adsorb significantly on GaAs at low NH4OH concentrations. The surface coverage and structural organization of these assemblies improve with increasing NH4OH concentrations, although these assemblies are never as organized as those from EtOH. The difference in the final structure of TPDT assemblies is attributed to differences in the thiolate fraction in the assembly solution at the point of substrate immersion.

  6. Impact of in vitro gallium arsenide exposure on macrophages.

    Science.gov (United States)

    Harrison, M Travis; Hartmann, Constance B; McCoy, Kathleen L

    2003-01-01

    The semiconductor gallium arsenide (GaAs) is classified as an immunotoxicant and a carcinogen. We previously showed that GaAs in vivo induces several phenotypic changes in macrophages located at the exposure site, indicative of an activated state. These physiological alterations may be a primary or secondary consequence of chemical exposure. To discern primary influences, our current study examined the in vitro effects of the chemical on macrophage cell lines and murine peritoneal macrophages. GaAs augmented cathepsins L and B proteolytic activities in all three sources of macrophages. Expression of the two mature isoforms of invariant chain and its cleavage fragment was also significantly increased, indicating that the chemical directly affects macrophages. However, GaAs did not alter the overall cell surface expression of major histocompatibility complex class II molecules on macrophages nor influence their ability to stimulate antigen-specific helper T cell hybridomas to respond to intact antigens that require processing. These findings raise the possibility that the chemical's complete in vivo impact may involve cytokines. Further, GaAs in vitro enhanced steady-state cathepsin L protein, and cathepsins L and B mRNA expression in macrophages, indicating that GaAs may alter gene expression, which may contribute to the chemical's adverse biological effects. Copyright 2003 Elsevier Science (USA)

  7. Enhanced photothermal conversion in vertically oriented gallium arsenide nanowire arrays.

    Science.gov (United States)

    Walia, Jaspreet; Dhindsa, Navneet; Flannery, Jeremy; Khodabad, Iman; Forrest, James; LaPierre, Ray; Saini, Simarjeet S

    2014-10-08

    The photothermal properties of vertically etched gallium arsenide nanowire arrays are examined using Raman spectroscopy. The nanowires are arranged in square lattices with a constant pitch of 400 nm and diameters ranging from 50 to 155 nm. The arrays were illuminated using a 532 nm laser with an incident energy density of 10 W/mm(2). Nanowire temperatures were highly dependent on the nanowire diameter and were determined by measuring the spectral red-shift for both TO and LO phonons. The highest temperatures were observed for 95 nm diameter nanowires, whose top facets and sidewalls heated up to 600 and 440 K, respectively, and decreased significantly for the smaller or larger diameters studied. The diameter-dependent heating is explained by resonant coupling of the incident laser light into optical modes of the nanowires, resulting in increased absorption. Photothermal activity in a given nanowire diameter can be optimized by proper wavelength selection, as confirmed using computer simulations. This demonstrates that the photothermal properties of GaAs nanowires can be enhanced and tuned by using a photonic lattice structure and that smaller nanowire diameters are not necessarily better to achieve efficient photothermal conversion. The diameter and wavelength dependence of the optical coupling could allow for localized temperature gradients by creating arrays which consist of different diameters.

  8. Gallium arsenide exposure impairs splenic B cell accessory function.

    Science.gov (United States)

    Gondre-Lewis, Timothy A; Hartmann, Constance B; Caffrey, Rebecca E; McCoy, Kathleen L

    2003-03-01

    Gallium arsenide (GaAs) is utilized in industries for its semiconductor and optical properties. Chemical exposure of animals systemically suppresses several immune functions. The ability of splenic B cells to activate antigen-specific helper CD4(+) T cell hybridomas was assessed, and various aspects of antigen-presenting cell function were examined. GaAs-exposed murine B cells were impaired in processing intact soluble protein antigens, and the defect was antigen dependent. In contrast, B cells after exposure competently presented peptides to the T cells, which do not require processing. Cell surface expression of major histocompatibility complex (MHC) class II molecules and several costimulatory molecules on splenic B cells, which are critical for helper T cell activation, was not affected by chemical exposure. GaAs exposure also did not influence the stability of MHC class II heterodimers, suggesting that the defect may precede peptide exchange. GaAs-exposed B cells contained a normal level of aspartyl cathepsin activity; however, proteolytic activities of thiol cathepsins B and L were approximately half the control levels. Furthermore, two cleavage fragments of invariant chain, a molecular chaperone of MHC class II molecules, were increased in GaAs-exposed B cells, indicative of defective degradation. Thus, diminished thiol proteolytic activity in B cells may be responsible for their impaired antigen processing and invariant chain degradation, which may contribute to systemic immunosuppression caused by GaAs exposure.

  9. Wide band gap gallium arsenide nanoparticles fabricated using plasma method

    Energy Technology Data Exchange (ETDEWEB)

    Jain, D., E-mail: dvjainnov@gmail.com [Physics Department, Banasthali Vidyapith, Rajasthan-304022 (India); Mangla, O. [Department of Physics and Astrophysics, University of Delhi, Delhi, 110007 (India); Physics Department, Hindu College, University of Delhi, Delhi, 110007 (India); Roy, S. [Physics Department, Daulat Ram College, University of Delhi, Delhi, 110007 (India)

    2016-05-23

    In this paper, we have reported the fabrication of gallium arsenide (GaAs) nanoparticles on quartz placed at distance of 4.0 cm, 5.0 cm and 6.0 cm, respectively from top of anode. The fabrication has been carried out by highly energetic and high fluence ions of GaAs produced by hot, dense and extremely non-equilibrium plasma in a modified dense plasma focus device. GaAs nanoparticles have mean size of about 23 nm, 16 nm and 14 nm for deposition at a distance of 4.0 cm, 5.0 cm and 6.0 cm, respectively. The nanoparticles are crystalline in nature as evident from X-ray diffraction patterns. The band gap of nanoparticles is found to increase from 1.425 eV to 5.37 eV at 4.0 cm distance, which further increases as distance increases. The wide band gap observed for fabricated GaAs nanoparticles suggest the possible applications of nanoparticles in laser systems.

  10. Aluminium Toxicity Targets in Plants

    Directory of Open Access Journals (Sweden)

    Sónia Silva

    2012-01-01

    Full Text Available Aluminium (Al is the third most abundant metallic element in soil but becomes available to plants only when the soil pH drops below 5.5. At those conditions, plants present several signals of Al toxicity. As reported by literature, major consequences of Al exposure are the decrease of plant production and the inhibition of root growth. The root growth inhibition may be directly/indirectly responsible for the loss of plant production. In this paper the most remarkable symptoms of Al toxicity in plants and the latest findings in this area are addressed. Root growth inhibition, ROS production, alterations on root cell wall and plasma membrane, nutrient unbalances, callose accumulation, and disturbance of cytoplasmic Ca2+ homeostasis, among other signals of Al toxicity are discussed, and, when possible, the behavior of Al-tolerant versus Al-sensitive genotypes under Al is compared.

  11. Piecewise simulaton proton test of gallium arsenide and thin silicon solar cells

    Science.gov (United States)

    Peterson, D. G.; Billets, S. A.

    1984-01-01

    Gallium Arsenide (GaAs) solar cells are viewed as a potential primary power source on certain future Earth orbiting satellites. However, the relative merits of gallium arsenide over silicon in a space radiation environment are largely unknown because a general degradation model for gallium arsenide does not exist. The results of a test simulating the proton radiation environment existing in a polar orbit and the concomitant effects on GaAs and thin silicon (Si) solar cells are presented. The objectives and methodology of the simulation test were discussed. The electrical characteristics of GaAs and Si solar cells are given in graph form. It was concluded that GaAs cells are viable for use on satellites in low Earth orbit.

  12. Solvent-dependent assembly of terphenyl- and quaterphenyldithiol on gold and gallium arsenide.

    Science.gov (United States)

    Krapchetov, Dmitry A; Ma, Hong; Jen, Alex K Y; Fischer, Daniel A; Loo, Yueh-Lin

    2005-06-21

    The assembly of terphenyldithiol (TPDT) and quaterphenyldithiol (QPDT) on gold and gallium arsenide from ethanol (EtOH), tetrahydrofuran (THF), and solutions consisting of both solvents has been characterized by near-edge X-ray absorption fine structure spectroscopy. The surface coverage and the average orientation of both TPDT and QPDT on gold are solvent-independent. These molecules readily form monolayers on gold with an ensemble-average backbone tilt of 30 degrees +/- 3 degrees from the substrate normal. In sharp contrast, the assembly of TPDT and QPDT on gallium arsenide is extremely solvent-sensitive. At high ethanol fractions, both molecules form monolayers with an ensemble-average orientation that is indistinguishable from those on gold substrates. At low ethanol fractions and in pure THF, however, these molecules are disordered on gallium arsenide and the surface coverage is poor.

  13. Magnetoelectric effect in layered structures of amorphous ferromagnetic alloy and gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Bichurin, M.I., E-mail: mirza.bichurin@novsu.ru; Petrov, V.M.; Leontiev, V.S.; Ivanov, S.N.; Sokolov, O.V.

    2017-02-15

    A paper devotes to theoretical and experimental studying the magnetoelectric interaction in layered structures of amorphous ferromagnetic alloy and single- crystal gallium arsenide. The authors investigated the magnetoelectric effect in the (100) plane of gallium arsenide in the electromechanical resonance range of 200–240 kHz and obtained maximal ME voltage coefficient of 120 V/A at bias field equaled 3.6 kA/m for the direction parallel to the [011] axis. Also the magnetoelectric effect in the (110) and (111) planes is discussed. The results can be used for design of new electronic devices based on the magnetostrictive-semiconductor materials. - Highlights: • Theoretical modeling of ME interaction was conducted. • Experimental dependencies in the resonance range were done. • Maximal ME effect of gallium arsenide was observed.

  14. Irradiation effects in magnesium and aluminium alloys

    International Nuclear Information System (INIS)

    Sturcken, E.F.

    1979-01-01

    Effects of neutron irradiation on microstructure, mechanical properties and swelling of several magnesium and aluminium alloys were studied. The neutron fluences of 2-3 X 10 22 n/cm 2 , >0.2 MeV produced displacement doses of 20 to 45 displacements per atom (dpa). Ductility of the magnesium alloys was severely reduced by irradiation induced recrystallization and precipitation of various forms. Precipitation of transmuted silicon occurred in the aluminium alloys. However, the effect on ductility was much less than for the magnesium alloys. The magnesium and aluminium alloys had excellent resistance to swelling: The best magnesium alloy was Mg/3.0 wt% Al/0.19 wt% Ca; its density decreased by only 0.13%. The best aluminium alloy was 6063, with a density decrease of 0.22%. (Auth.)

  15. Deformation features of aluminium in tensile tests

    International Nuclear Information System (INIS)

    Quadros, N.F. de.

    1984-01-01

    It is presented a method to analyse stress-strain curves. Plastic and elastic strains were studied. The strains were done by tensile tests in four types of materials: highly pure aluminium, pure aluminium, commercially pure aluminium and aluminium - uranium. The chemical compositions were obtained by spectroscopy analysis and neutron activation analysis. Tensile tests were carried out at three strain rates, at room temperature, 100,200, 300 and 400 0 C, with knives extensometer and strain-gages to studied the elastic strain region. A multiple spring model based on two springs model to analyse elastic strain caused by tests without extensometers, taking in account moduli of elasticity and, an interactive analysis system with graphic capability were developed. It was suggested a qualitative model to explain the quantized multielasticity of Bell. (M.C.K.) [pt

  16. Aluminium Process Fault Detection and Diagnosis

    Directory of Open Access Journals (Sweden)

    Nazatul Aini Abd Majid

    2015-01-01

    Full Text Available The challenges in developing a fault detection and diagnosis system for industrial applications are not inconsiderable, particularly complex materials processing operations such as aluminium smelting. However, the organizing into groups of the various fault detection and diagnostic systems of the aluminium smelting process can assist in the identification of the key elements of an effective monitoring system. This paper reviews aluminium process fault detection and diagnosis systems and proposes a taxonomy that includes four key elements: knowledge, techniques, usage frequency, and results presentation. Each element is explained together with examples of existing systems. A fault detection and diagnosis system developed based on the proposed taxonomy is demonstrated using aluminium smelting data. A potential new strategy for improving fault diagnosis is discussed based on the ability of the new technology, augmented reality, to augment operators’ view of an industrial plant, so that it permits a situation-oriented action in real working environments.

  17. The comparison between gallium arsenide and indium gallium arsenide as materials for solar cell performance using Silvaco application

    International Nuclear Information System (INIS)

    Zahari, Suhaila Mohd; Norizan, Mohd Natashah; Mohamad, Ili Salwani; Osman, Rozana Aina Maulat; Taking, Sanna

    2015-01-01

    The work presented in this paper is about the development of single and multilayer solar cells using GaAs and InGaAs in AM1.5 condition. The study includes the modeling structure and simulation of the device using Silvaco applications. The performance in term of efficiency of Indium Gallium Arsenide (InGaAs) and GaAs material was studied by modification of the doping concentration and thickness of material in solar cells. The efficiency of the GaAs solar cell was higher than InGaAs solar cell for single layer solar cell. Single layer GaAs achieved an efficiency about 25% compared to InGaAs which is only 2.65% of efficiency. For multilayer which includes both GaAs and InGaAs, the output power, P max was 8.91nW/cm² with the efficiency only 8.51%. GaAs is one of the best materials to be used in solar cell as a based compared to InGaAs

  18. The comparison between gallium arsenide and indium gallium arsenide as materials for solar cell performance using Silvaco application

    Energy Technology Data Exchange (ETDEWEB)

    Zahari, Suhaila Mohd; Norizan, Mohd Natashah; Mohamad, Ili Salwani; Osman, Rozana Aina Maulat; Taking, Sanna [School of Microelectronic Engineering, Universiti Malaysia Perlis, Kampus Pauh Putra, 02600 Arau, Perlis (Malaysia)

    2015-05-15

    The work presented in this paper is about the development of single and multilayer solar cells using GaAs and InGaAs in AM1.5 condition. The study includes the modeling structure and simulation of the device using Silvaco applications. The performance in term of efficiency of Indium Gallium Arsenide (InGaAs) and GaAs material was studied by modification of the doping concentration and thickness of material in solar cells. The efficiency of the GaAs solar cell was higher than InGaAs solar cell for single layer solar cell. Single layer GaAs achieved an efficiency about 25% compared to InGaAs which is only 2.65% of efficiency. For multilayer which includes both GaAs and InGaAs, the output power, P{sub max} was 8.91nW/cm² with the efficiency only 8.51%. GaAs is one of the best materials to be used in solar cell as a based compared to InGaAs.

  19. The comparison between gallium arsenide and indium gallium arsenide as materials for solar cell performance using Silvaco application

    Science.gov (United States)

    Zahari, Suhaila Mohd; Norizan, Mohd Natashah; Mohamad, Ili Salwani; Osman, Rozana Aina Maulat; Taking, Sanna

    2015-05-01

    The work presented in this paper is about the development of single and multilayer solar cells using GaAs and InGaAs in AM1.5 condition. The study includes the modeling structure and simulation of the device using Silvaco applications. The performance in term of efficiency of Indium Gallium Arsenide (InGaAs) and GaAs material was studied by modification of the doping concentration and thickness of material in solar cells. The efficiency of the GaAs solar cell was higher than InGaAs solar cell for single layer solar cell. Single layer GaAs achieved an efficiency about 25% compared to InGaAs which is only 2.65% of efficiency. For multilayer which includes both GaAs and InGaAs, the output power, Pmax was 8.91nW/cm² with the efficiency only 8.51%. GaAs is one of the best materials to be used in solar cell as a based compared to InGaAs.

  20. Computer simulation of the aluminium extrusion process

    Directory of Open Access Journals (Sweden)

    A. Śliwa

    2017-01-01

    Full Text Available The purpose of the work is computer simulation of the aluminium extrusion process using the Finite elements method (FEM. The impact of the speed of a punch falling on the material in the aluminium extrusion process was investigated. It was found that high stresses are created, leading to material destruction, if the punch is falling too fast. The design cycle is significantly reduced in multiple industrial applications if the FEM is applied, which enhances productivity and profits.

  1. Characterization of aluminium alloys rapidly solidified

    International Nuclear Information System (INIS)

    Monteiro, W.A.

    1988-01-01

    This paper discussed the investigation of the microstructural and mechanical properties of the aluminium alloys (3003; 7050; Al-9% Mg) rapidly solidified by melt spinning process (cooling rate 10 4 - 10 6 K/s). The rapidly solidification process of the studied aluminium alloys brought a microcrystallinity, a minimum presence of coarse precipitation and, also, better mechanical properties of them comparing to the same alloys using ingot process. (author) [pt

  2. Aluminium phosphide induced acute kidney injury

    Directory of Open Access Journals (Sweden)

    Quaiser Saif

    2015-01-01

    Full Text Available Aluminium phosphide is one of the most common agricultural poisons being consumed in north India. Consumption of a fresh tablet is lethal as no antidote is available. Acute intoxication primarily presents with cardiovascular collapse due to myocardial toxicity. We report here a case of acute severe poisoning along with cardiovascular collapse and oliguria. The patient developed acute kidney injury during the illness (a rare entity in aluminium phosphide poisoning, which completely resolved following prompt conservative treatment.

  3. Properties of gallium arsenide alloyed with Ge and Se by irradiation in nuclear reactor thermal column

    International Nuclear Information System (INIS)

    Kolin, N.G.; Osvenskij, V.B.; Tokarevskij, V.V.; Kharchenko, V.A.; Ievlev, S.M.

    1985-01-01

    Dependences of electrophysical properties as well as lattice unit spacing and density of nuclear-alloyed gallium arsenide on the fluence of reactor neutrons and heat treatment are investigated. Neutron radiation of gallium arsenide with different energy spectra is shown to differently affect material properties. Fast neutrons make the main contribution to defect formation. Concentration of compensating acceptor defects formed under GaAs radiation in a thermal column practically equals concentration of introduced donor impurities. Radiation defects of acceptor type are not annealed in the material completely even at 900-1000 deg C

  4. Noise suppression and long-range exchange coupling for gallium arsenide spin qubits

    DEFF Research Database (Denmark)

    Malinowski, Filip

    This thesis presents the results of the experimental study performed on spin qubits realized in gate-defined gallium arsenide quantum dots, with the focus on noise suppression and long-distance coupling. First, we show that the susceptibility to charge noise can be reduced by reducing the gradient...... to put the highest, up to date, lower bound on the electron spin coherence time in gallium arsenide: 870 ms. Later, we study the perspectives of exploiting a multielectron quantum dot as a mediator of the exchange interaction. We investigate interaction between a single spin and the multelectron quantum...

  5. Aluminium exclusion and aluminium tolerance in woody plants

    Directory of Open Access Journals (Sweden)

    Ivano eBrunner

    2013-06-01

    Full Text Available The aluminium (Al cation Al3+ is highly rhizotoxic and is a major stress factor to plants on acid soils, which cover large areas of tropical and boreal regions. Many woody plant species are native to acid soils and are well adapted to high Al3+ conditions. In tropical regions, both woody Al accumulator and non-Al accumulator plants occur, whereas in boreal regions woody plants are non-Al accumulators. The mechanisms of these adaptations can be divided into those that facilitate the exclusion of Al3+ from root cells (exclusion mechanisms and those that enable plants to tolerate Al3+ once it has entered the root and shoot symplast (internal tolerance mechanisms. The biochemical and molecular basis of these mechanisms have been intensively studied in several crop plants and the model plant Arabidopsis. In this review, we examine the current understanding of Al3+ exclusion and tolerance mechanisms from woody plants. In addition, we discuss the ecology of woody non-Al accumulator and Al accumulator plants, and present examples of Al3+ adaptations in woody plant populations. This paper complements previous reviews focusing on crop plants and provides insights into evolutionary processes operating in plant communities that are widespread on acid soils.

  6. Progress to a Gallium-Arsenide Deep-Center Laser

    Directory of Open Access Journals (Sweden)

    Janet L. Pan

    2009-10-01

    Full Text Available Although photoluminescence from gallium-arsenide (GaAs deep-centers was first observed in the 1960s, semiconductor lasers have always utilized conduction-to-valence-band transitions. Here we review recent materials studies leading to the first GaAs deep-center laser. First, we summarize well-known properties: nature of deep-center complexes, Franck-Condon effect, hotoluminescence. Second, we describe our recent work: insensitivity of photoluminescence with heating, striking differences between electroluminescence and photoluminescence, correlation between transitions to deep-states and absence of bandgap-emission. Room-temperature stimulated-emission from GaAs deep-centers was observed at low electrical injection, and could be tuned from the bandgap to half-the-bandgap (900–1,600 nm by changing the electrical injection. The first GaAs deep-center laser was demonstrated with electrical injection, and exhibited a threshold of less than 27 mA/cm2 in continuous-wave mode at room temperature at the important 1.54 μm fiber-optic wavelength. This small injection for laser action was explained by fast depopulation of the lower state of the optical transition (fast capture of free holes onto deep-centers, which maintains the population inversion. The evidence for laser action included: superlinear L-I curve, quasi-Fermi level separations satisfying Bernard-Duraffourg’s criterion, optical gains larger than known significant losses, clamping of the optical-emission from lossy modes unable to reach laser action, pinning of the population distribution during laser action.

  7. Combined Silicon and Gallium Arsenide Solar Cell UV Testing

    Science.gov (United States)

    Willowby, Douglas

    2005-01-01

    The near and long-term effect of UV on silicon solar cells is relatively understood. In an effort to learn more about the effects of UV radiation on the performance of GaAs/Ge solar cells, silicon and gallium arsenide on germanium (GaAs/Ge) solar cells were placed in a vacuum chamber and irradiated with ultraviolet light by a Spectrolab XT 10 solar simulator. Seventeen GaAs/Ge and 8 silicon solar cells were mounted on an 8 inch copper block. By having all the cells on the same test plate we were able to do direct comparison of silicon and GaAs/Ge solar cell degradation. The test article was attached to a cold plate in the vacuum chamber to maintain the cells at 25 degrees Celsius. A silicon solar cell standard was used to measure beam uniformity and any degradation of the ST-10 beam. The solar cell coverings tested included cells with AR-0213 coverglass, fused silica coverglass, BRR-0213 coverglass and cells without coverglass. Of interest in the test is the BRR-0213 coverglass material manufactured by OCLI. It has an added Infrared rejection coating to help reduce the solar cell operating temperature. This coverglass is relatively new and of interest to several current and future programs at Marshall. Due to moves of the laboratory equipment and location only 350 hours of UV degradation have been completed. During this testing a significant leveling off in the rate of degradation was reached. Data from the test and comparisons of the UV effect of the bare cells and cells with coverglass material will be presented.

  8. Indium Phosphide Window Layers for Indium Gallium Arsenide Solar Cells

    Science.gov (United States)

    Jain, Raj K.

    2005-01-01

    Window layers help in reducing the surface recombination at the emitter surface of the solar cells resulting in significant improvement in energy conversion efficiency. Indium gallium arsenide (In(x)Ga(1-x)As) and related materials based solar cells are quite promising for photovoltaic and thermophotovoltaic applications. The flexibility of the change in the bandgap energy and the growth of InGaAs on different substrates make this material very attractive for multi-bandgap energy, multi-junction solar cell approaches. The high efficiency and better radiation performance of the solar cell structures based on InGaAs make them suitable for space power applications. This work investigates the suitability of indium phosphide (InP) window layers for lattice-matched In(0.53)Ga(0.47)As (bandgap energy 0.74 eV) solar cells. We present the first data on the effects of the p-type InP window layer on p-on-n lattice-matched InGaAs solar cells. The modeled quantum efficiency results show a significant improvement in the blue region with the InP window. The bare InGaAs solar cell performance suffers due to high surface recombination velocity (10(exp 7) cm/s). The large band discontinuity at the InP/InGaAs heterojunction offers a great potential barrier to minority carriers. The calculated results demonstrate that the InP window layer effectively passivates the solar cell front surface, hence resulting in reduced surface recombination and therefore, significantly improving the performance of the InGaAs solar cell.

  9. Noble Metal Arsenides and Gold Inclusions in Northwest Africa 8186

    Science.gov (United States)

    Srinivasan, P.; McCubbin, F. M.; Rahman, Z.; Keller, L. P.; Agee, C. B.

    2016-01-01

    CK carbonaceous chondrites are a highly thermally altered group of carbonaceous chondrites, experiencing temperatures ranging between approximately 576-867 degrees Centigrade. Additionally, the mineralogy of the CK chondrites record the highest overall oxygen fugacity of all chondrites, above the fayalite-magnetite-quartz (FMQ) buffer. Me-tallic Fe-Ni is extremely rare in CK chondrites, but magnetite and Fe,Ni sulfides are commonly observed. Noble metal-rich inclusions have previously been found in some magnetite and sulfide grains. These arsenides, tellurides, and sulfides, which contain varying amounts of Pt, Ru, Os, Te, As, Ir, and S, are thought to form either by condensation from a solar gas, or by exsolution during metamorphism on the chondritic parent body. Northwest Africa (NWA) 8186 is a highly metamorphosed CK chondrite. This meteorite is predominately composed of NiO-rich forsteritic olivine (Fo65), with lesser amounts of plagioclase (An52), augite (Fs11Wo49), magnetite (with exsolved titanomagnetite, hercynite, and titanohematite), monosulfide solid solution (with exsolved pentlandite), and the phosphate minerals Cl-apatite and merrillite. This meteorite contains coarse-grained, homogeneous silicates, and has 120-degree triple junctions between mineral phases, which indicates a high degree of thermal metamorphism. The presence of NiO-rich olivine, oxides phases all bearing Fe3 plus, and the absence of metal, are consistent with an oxygen fugacity above the FMQ buffer. We also observed noble metal-rich phases within sulfide grains in NWA 8186, which are the primary focus of the present study.

  10. Progress to a Gallium-Arsenide Deep-Center Laser

    Science.gov (United States)

    Pan, Janet L.

    2009-01-01

    Although photoluminescence from gallium-arsenide (GaAs) deep-centers was first observed in the 1960s, semiconductor lasers have always utilized conduction-to-valence-band transitions. Here we review recent materials studies leading to the first GaAs deep-center laser. First, we summarize well-known properties: nature of deep-center complexes, Franck-Condon effect, photoluminescence. Second, we describe our recent work: insensitivity of photoluminescence with heating, striking differences between electroluminescence and photoluminescence, correlation between transitions to deep-states and absence of bandgap-emission. Room-temperature stimulated-emission from GaAs deep-centers was observed at low electrical injection, and could be tuned from the bandgap to half-the-bandgap (900–1,600 nm) by changing the electrical injection. The first GaAs deep-center laser was demonstrated with electrical injection, and exhibited a threshold of less than 27 mA/cm2 in continuous-wave mode at room temperature at the important 1.54 μm fiber-optic wavelength. This small injection for laser action was explained by fast depopulation of the lower state of the optical transition (fast capture of free holes onto deep-centers), which maintains the population inversion. The evidence for laser action included: superlinear L-I curve, quasi-Fermi level separations satisfying Bernard-Duraffourg’s criterion, optical gains larger than known significant losses, clamping of the optical-emission from lossy modes unable to reach laser action, pinning of the population distribution during laser action.

  11. Structural, energetic, and electronic properties of hydrogenated aluminum arsenide clusters

    Science.gov (United States)

    Guo, Ling

    2011-05-01

    The chemisorptions of hydrogen on aluminum arsenide clusters are studied with density functional theory (DFT). The on-top site is identified to be the most favorable chemisorptions site for hydrogen. And the Al-top site is the preferred one in the most cases for one hydrogen adsorption in (AlAs) n ( n = 2, 5, 6, 8-15) clusters. Top on the neighboring Al and As atoms ground-state structures are found for two hydrogen adsorption on (AlAs) n except for (AlAs)2 cluster. The Al-As bond lengths decrease generally as the size of the cluster increases. And there is a slight increase in the mean Al-As bond lengths after H adsorption on the lowest-energy sites of the most AlAs clusters. In general, the binding energy of H and 2H are both found to decrease with an increase in the cluster size. And the result shows that large binding energies (BE) of a single hydrogen atom on small AlAs clusters and large highest occupied and lowest unoccupied molecular-orbital gaps for (AlAs)H and (AlAs)3H make these species behaving like magic clusters. Calculations on two hydrogen atoms on (AlAs) n clusters show large BE for (AlAs) n H2 with an odd number of n. The stability of these complexes is further studied from the fragmentation energies. (AlAs)7H2 and (AlAs)9H2 clusters are again suggested to be the stable clusters. On the other hand both the fragmentation energy and the binding energy for (AlAs)13H are close to the lowest values.

  12. TEM investigation of aluminium containing precipitates in high aluminium doped silicon carbide

    International Nuclear Information System (INIS)

    Wong-Leung, J.; FitzGerald, J.D.

    2002-01-01

    Full text: Silicon carbide is a promising semiconductor material for applications in high temperature and high power devices. The successful growth of good quality epilayers in this material has enhanced its potential for device applications. As a novel semiconductor material, there is a need for studying its basic physical properties and the role of dopants in this material. In this study, silicon carbide epilayers were grown on 4H-SiC wafers of (0001) orientation with a miscut angle of 8 deg at a temperature of 1550 deg C. The epilayers contained regions of high aluminium doping well above the solubility of aluminium in silicon carbide. High temperature annealing of this material resulted in the precipitation of aluminium in the wafers. The samples were analysed by secondary ion mass spectrometry and transmission electron microscopy. Selected area diffraction studies show the presence of aluminium carbide and aluminium silicon carbide phases. Copyright (2002) Australian Society for Electron Microscopy Inc

  13. Aluminium toxicity in winter wheat

    Directory of Open Access Journals (Sweden)

    Szabó A.

    2015-01-01

    Full Text Available Aluminium is the most frequent metal of the earth crust; it occurs mainly as biologically inactive, insoluble deposit. Environmental problems, industrial contaminations and acid rains increase the soil acidity, leading to the mobilization of Al. Half of the world’s potential arable lands are acidic; therefore, Al-toxicity decreases crop productivity. Wheat is a staple food for 35% of the world population. The effects of Al-stress (0.1 mM were studied on winter wheat; seedlings were grown hydroponically, at acidic pH. After two weeks, the root weight was decreased; a significant difference was found in the P- and Ca-content. The shoot weight and element content changed slightly; Al-content in the root was one magnitude higher than in the shoot, while Al-translocation was limited. The root plasma membrane H+-ATPase has central role in the uptake processes; Al-stress increased the Mg2+-ATPase activity of the microsomal fraction.

  14. Light transport through disordered layers of dense gallium arsenide submicron particles

    NARCIS (Netherlands)

    Van der Beek, T.; Barthelemy, P.J.C.; Johnson, P.M.; Wiersma, D.S.; Lagendijk, A.

    2012-01-01

    We present a study of optical transport properties of powder layers with submicrometer, strongly scattering gallium arsenide (GaAs) particles. Uniform, thin samples with well controlled thicknesses were created through the use of varying grinding times, sedimentation fractionation, annealing, and a

  15. Effect of aluminium phosphate as admixture on oxychloride cement

    Indian Academy of Sciences (India)

    Abstract. The effect of admixing of aluminium phosphate on oxychloride cement in the matrix has been investigated. It is shown that aluminium phosphate retards the setting process of the cement and improves water-tightness.

  16. Aluminium Diphosphamethanides: Hidden Frustrated Lewis Pairs.

    Science.gov (United States)

    Styra, Steffen; Radius, Michael; Moos, Eric; Bihlmeier, Angela; Breher, Frank

    2016-07-04

    The synthesis and characterisation of two aluminium diphosphamethanide complexes, [Al(tBu)2 {κ(2) P,P'-Mes*PCHPMes*}] (3) and [Al(C6 F5 )2 {κ(2) P,P'-Mes*PCHPMes*}] (4), and the silylated analogue, Mes*PCHP(SiMe3 )Mes* (5), are reported. The aluminium complexes feature four-membered PCPAl core structures consisting of diphosphaallyl ligands. The silylated phosphine 5 was found to be a valuable precursor for the synthesis of 4 as it cleanly reacts with the diaryl aluminium chloride [(C6 F5 )2 AlCl]2 . The aluminium complex 3 reacts with molecular dihydrogen at room temperature under formation of the acyclic σ(2) λ(3) ,σ(3) λ(3) -diphosphine Mes*PCHP(H)Mes* and the corresponding dialkyl aluminium hydride [tBu2 AlH]3 . Thus, 3 belongs to the family of so-called hidden frustrated Lewis pairs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Steam Assisted Accelerated Growth of Oxide Layer on Aluminium Alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Yuksel, Serkan; Jellesen, Morten Stendahl

    2013-01-01

    Corrosion resistance of aluminium alloys is related to the composition and morphology of the oxide film on the surface of aluminium. In this paper we investigated the use of steam on the surface modification of aluminium to produce boehmite films. The study reveals a detailed investigation...... of the effect of vapour pressure, structure of intermetallic particles and thickness of boehmite films on the corrosion behaviour of aluminium alloys....

  18. Aluminium contents in infant and follow-on formula

    OpenAIRE

    German Federal Institute for Risk Assessment

    2012-01-01

    The presence of aluminium in food can have different causes. Thus, for example, it can be due to natural contents in certain food ingredients or aluminium-containing additives. Another source can be the transfer of aluminium from food packaging, cooking utensils, or kitchen equipment etc. Below, the Federal Institute for Risk Assessment (BfR) assesses aluminium contents in baby food with regard to their potential health effects. The trigger for the BfR opinion was a British study which me...

  19. Continuum modelling of silicon diffusion in indium gallium arsenide

    Science.gov (United States)

    Aldridge, Henry Lee, Jr.

    A possible method to overcome the physical limitations experienced by continued transistor scaling and continue improvements in performance and power consumption is integration of III-V semiconductors as alternative channel materials for logic devices. Indium Gallium Arsenide (InGaAs) is such a material from the III-V semiconductor family, which exhibit superior electron mobilities and injection velocities than that of silicon. In order for InGaAs integration to be realized, contact resistances must be minimized through maximizing activation of dopants in this material. Additionally, redistribution of dopants during processing must be clearly understood and ultimately controlled at the nanometer-scale. In this work, the activation and diffusion behavior of silicon, a prominent n-type dopant in InGaAs, has been characterized and subsequently modelled using the Florida Object Oriented Process and Device Simulator (FLOOPS). In contrast to previous reports, silicon exhibits non-negligible diffusion in InGaAs, even for smaller thermal budget rapid thermal anneals (RTAs). Its diffusion is heavily concentration-dependent, with broadening "shoulder-like" profiles when doping levels exceed 1-3x1019cm -3, for both ion-implanted and Molecular Beam Epitaxy (MBE)-grown cases. Likewise a max net-activation value of ˜1.7x1019cm -3 is consistently reached with enough thermal processing, regardless of doping method. In line with experimental results and several ab-initio calculation results, rapid concentration-dependent diffusion of Si in InGaAs and the upper limits of its activation is believed to be governed by cation vacancies that serve as compensating defects in heavily n-type regions of InGaAs. These results are ultimately in line with an amphoteric defect model, where the activation limits of dopants are an intrinsic limitation of the material, rather than governed by individual dopant species or their methods of incorporation. As a result a Fermi level dependent point

  20. Gallium interstitial contributions to diffusion in gallium arsenide

    Science.gov (United States)

    Schick, Joseph T.; Morgan, Caroline G.

    2011-09-01

    encountered in fitting experimental results for heavily p-type, Ga-rich gallium arsenide by simply extending a model for gallium interstitial diffusion which has been used for less p-doped material.

  1. Gallium interstitial contributions to diffusion in gallium arsenide

    Directory of Open Access Journals (Sweden)

    Joseph T. Schick

    2011-09-01

    have been encountered in fitting experimental results for heavily p-type, Ga-rich gallium arsenide by simply extending a model for gallium interstitial diffusion which has been used for less p-doped material.

  2. Analysis of aluminium in rat following administration of allergen immunotherapy using either aluminium or microcrystalline-tyrosine-based adjuvants.

    Science.gov (United States)

    McDougall, Stuart A; Heath, Matthew D; Kramer, Matthias F; Skinner, Murray A

    2016-03-01

    Investigation into the absorption, distribution and elimination of aluminium in rat after subcutaneous aluminium adjuvant formulation administration using ICP-MS is described. Assays were verified under the principles of a tiered approach. There was no evidence of systemic exposure of aluminium, in brain or in kidney. Extensive and persistent retention of aluminium at the dose site was observed for at least 180 days after administration. This is the first published work that has quantified aluminium adjuvant retention based on the quantity of aluminium delivered in a typical allergy immunotherapy course. The results indicate that the repeated administration of aluminium-containing adjuvants will likely contribute directly and significantly to an individual's body burden of aluminium.

  3. Aluminium toxicity tolerance in crop plants: Present status of research

    African Journals Online (AJOL)

    ... tolerance of which genes of the Aluminium-activated malate transporter (ALMT) and multidrug and toxic compound extrusion (MATE) families are prominent. In this review, the progress of research in identifying aluminium toxicity tolerant genes is discussed. Keywords: Aluminium toxicity, soil acidity, hydroponic screening, ...

  4. Aluminium allergy and granulomas induced by vaccinations for children

    DEFF Research Database (Denmark)

    Andersen, Rosa Marie O; Zachariae, Claus; Johansen, Jeanne Duus

    2014-01-01

    Vaccination with aluminium-adsorbed vaccines can induce aluminium allergy with persistent itching subcutaneous nodules at the injection site - vaccination granulomas. In this article we give an overview of childhood aluminium-adsorbed vaccines available in Denmark. Through literature studies we...... examine the incidence, the symptoms and the prognosis for the vaccination granulomas and the allergy. Finally we discuss the status in Denmark....

  5. Design and Analysis of Butterfly Valve Disc Using Aluminium (1100 ...

    African Journals Online (AJOL)

    Aluminium (1100) is an extensively used material in the application of water line and drainage applications. If the aluminium (1100) surface contacts the water, an oxide layer will be formed and it prevents the corrosion of aluminium (1100) when compared to other metal and also it has less weight. But due to their low ...

  6. [Aluminium allergy and granulomas induced by vaccinations for children].

    Science.gov (United States)

    Andersen, Rosa Marie Ø; Zachariae, Claus; Johansen, Jeanne Duus

    2015-04-27

    Vaccination with aluminium-adsorbed vaccines can induce aluminium allergy with persistent itching subcutaneous nodules at the injection site – vaccination granulomas. In this article we give an overview of childhood aluminium-adsorbed vaccines available in Denmark. Through literature studies we examine the incidence, the symptoms and the prognosis for the vaccination granulomas and the allergy. Finally we discuss the status in Denmark.

  7. Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders

    NARCIS (Netherlands)

    De Kanter, J.L.C.G.

    2006-01-01

    Summary accompanying the thesis: Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders by Jens de Kanter This thesis presents the investigation of the crush behaviour of both monolithic aluminium cylinders and externally fibre reinforced aluminium cylinders. The research is based

  8. Aluminium and the human breast.

    Science.gov (United States)

    Darbre, P D

    2016-06-01

    The human population is exposed to aluminium (Al) from diet, antacids and vaccine adjuvants, but frequent application of Al-based salts to the underarm as antiperspirant adds a high additional exposure directly to the local area of the human breast. Coincidentally the upper outer quadrant of the breast is where there is also a disproportionately high incidence of breast cysts and breast cancer. Al has been measured in human breast tissues/fluids at higher levels than in blood, and experimental evidence suggests that at physiologically relevant concentrations, Al can adversely impact on human breast epithelial cell biology. Gross cystic breast disease is the most common benign disorder of the breast and evidence is presented that Al may be a causative factor in formation of breast cysts. Evidence is also reviewed that Al can enable the development of multiple hallmarks associated with cancer in breast cells, in particular that it can cause genomic instability and inappropriate proliferation in human breast epithelial cells, and can increase migration and invasion of human breast cancer cells. In addition, Al is a metalloestrogen and oestrogen is a risk factor for breast cancer known to influence multiple hallmarks. The microenvironment is established as another determinant of breast cancer development and Al has been shown to cause adverse alterations to the breast microenvironment. If current usage patterns of Al-based antiperspirant salts contribute to causation of breast cysts and breast cancer, then reduction in exposure would offer a strategy for prevention, and regulatory review is now justified. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  9. Steam Initiated Surface Modification of Aluminium Alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud

    The extensive demand of aluminium alloys in various industries such as in transportationis mainly due to the high strength to weight ratio, which could be translated into fuel economy and efficiency. Corrosion protection of aluminium alloys is an important aspect for all applications which includes...... to 12 present various experimental results in the form of appended papers. The chapters consist of the experimental results obtained by the use of steam-based process and its effect on microstructureand corrosion resistance of the alloy as a function of steam pressure, use of various chemicals...... the use of aluminium alloys in the painted form requiring a conversion coating to improve the adhesion. Chromate based conversion coating processes are extremely good for these purposes, however the carcinogenic and toxic nature of hexavalent chromium led to the search for more benign and eco...

  10. Steam generated conversion coating on aluminium alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    Aluminium and its alloys are widely used in aerospace industry owing to their high strength to weight ratio. The surface of aluminium under normal conditions has a thin oxide film (2.5-10 nm) responsible for its inherent corrosion resistance. This oxide film can further be converted or transformed...... into functional conversion coatings in order to enhance corrosion resistance and adhesion to paint systems. Chromium based conversion coatings have been extensively used on aluminium alloys to improve adhesion of subsequent paint layers and corrosion resistance. However, the use of hexavalent chromium is strictly...... and growth of oxide film on different intermetallic particles and corrosion behaviour of such alloys.Surface morphology was observed by using FEG-SEM, EDX and FIB-SEM. Metal oxide surface characterization and compositional depth profiling were investigated by using XPS and GD-OES respectively...

  11. Internal friction in iron-aluminium alloys having a high aluminium content

    International Nuclear Information System (INIS)

    Hillairet, J.; Delaplace, J.; Silvent, A.

    1966-01-01

    By using a torsion pendulum to measure the internal friction of iron-aluminium alloys containing between 25 and 50 atom per cent of aluminium, it has been possible to show the existence of three damping peaks due to interstitial carbon. Their evolution is followed as a function of the carbon content, of the thermal treatment and of the aluminium content. A model based on the preferential occupation of tetrahedral sites is proposed as an interpretation of the results. A study of the Zener peak in these substitution alloys shows also that a part of the short distance disorder existing at high temperatures can be preserved by quenching. (author) [fr

  12. TITANIUM CARBON ALUMINIUM : A NOVEL GRAIN REFINER FOR ALUMINIUM-LITHIUM ALLOYS

    OpenAIRE

    Birch , M.; Cowell , A.

    1987-01-01

    This work explores the possibility of achieving grain size control in aluminium-lithium alloys with the titanium carbon aluminium (TiCAl) master alloys invented at the Technical University of Berlin and developed by London and Scandinavian Metallurgical Co Ltd (LSM). Grain refining tests were conducted on a single batch of 8090 alloy using addition rates of 0.2wt% and 0.4wt% of TiCAl and 3/1 titanium boron aluminium (TiBAl). Other tests using 0.4wt% of binary TiAl gave poor results, showing t...

  13. Effect of flyash particles with aluminium melt on the wear of aluminium metal matrix composites

    Directory of Open Access Journals (Sweden)

    Vipin K. Sharma

    2017-08-01

    Full Text Available The present work deals with the fabrication and tribological testing of an aluminium flyash composite. The metal matrix selected was aluminium and flyash contents in different percentages were reinforced in it to fabricate the required metal matrix composite (MMC. Stir casting method was used to fabricate the MMC with 2–4–6% weight of flyash contents in aluminium. Tribological analysis of the tribo pairs formed between the smooth surfaces of cast iron disc and smooth MMC pin has been considered and friction force and wear of the MMC were investigated by using a Pin-on-disc setup. It was observed that the MMC with 6% weight of flyash content in aluminium matrix results in less wear (0.32 g and 4% weight of flyash content gives the low coefficient of friction (0.12 between the tribopairs of cast iron surface and MMC surface.

  14. Thermal formation of corundum from aluminium hydroxides ...

    Indian Academy of Sciences (India)

    This contains a higher concentration of anionic impurities related to differences in the solubility of the original aluminium salts. The sulfate is retained in the gel to higher temperatures at which its eventual decomposition may lead to the formation of a reactive pore structure which facilitates the nucleation of -Al2O3.

  15. Indentation of aluminium foam at low velocity

    Directory of Open Access Journals (Sweden)

    Shi Xiaopeng

    2015-01-01

    Full Text Available The indentation behaviour of aluminium foams at low velocity (10 m/s ∼ 30 m/s was investigated both in experiments and numerical simulation in this paper. A flat-ended indenter was used and the force-displacement history was recorded. The Split Hopkinson Pressure bar was used to obtain the indentation velocity and forces in the dynamic experiments. Because of the low strength of the aluminium foam, PMMA bar was used, and the experimental data were corrected using Bacon's method. The energy absorption characteristics varying with impact velocity were then obtained. It was found that the energy absorption ability of aluminium foam gradually increases in the quasi-static regime and shows a significant increase at ∼10 m/s velocity. Numerical simulation was also conducted to investigate this process. A 3D Voronoi model was used and models with different relative densities were investigated as well as those with different failure strain. The indentation energy increases with both the relative density and failure strain. The analysis of the FE model implies that the significant change in energy absorption ability of aluminium foam in indentation at ∼10 m/s velocity may be caused by plastic wave effect.

  16. Performance evaluation of aluminium test piece against ...

    African Journals Online (AJOL)

    Image processing with Catphan 700 uses the automated Quality Assurance software restricted to only Digital Imaging and Communications in Medicine images. For this reason, an aluminium (Al) test piece device was fabricated for image processing in different image format for spatial resolution measurement.

  17. Warm Deep Drawing of Aluminium Sheet

    NARCIS (Netherlands)

    Bolt, P.J.; Werkhoven, R.J.; van den Boogaard, Antonius H.

    2003-01-01

    Aluminium sheet drawing processes can be improved by manipulating local flow behaviour by means of elevated temperatures and temperature gradients in the tooling. Forming tests showed that a substantial improvement is possible not only for 5xxx but also for 6xxx series alloys. Finite element method

  18. Flexural buckling of fire exposed aluminium columns

    NARCIS (Netherlands)

    Maljaars, J.; Twilt, L.; Soetens, F.

    2009-01-01

    In order to study buckling of fire exposed aluminium columns, a finite element model is developed. The results of this model are verified with experiments. Based on a parametric study with the finite element model, it is concluded that the simple calculation model for flexural buckling of fire

  19. Aluminium hydroxide-induced granulomas in pigs

    DEFF Research Database (Denmark)

    Valtulini, S; Macchi, C; Ballanti, P

    2005-01-01

    The effect of intramuscular injection of 40 mg/2 ml aluminium hydroxide in the neck of pigs was examined in a number of ways. The investigation followed repeated slaughterhouse reports, according to which 64.8% of pigs from one particular farm were found at slaughter to have one or more nodules i...

  20. Generation and characterization of nano aluminium powder ...

    Indian Academy of Sciences (India)

    TECS

    Abstract. In the present study, nano aluminium particles were produced by wire explosion process (WEP) in nitrogen, argon and helium atmospheres. Thus produced nano particles were characterized through certain physico-chemical diagnostic studies using wide angle X-ray diffraction (WAXD) and by energy dispersive.

  1. Impact toughness of laser surface alloyed Aluminium

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2012-03-01

    Full Text Available Laser surface alloying of aluminium AA1200 was performed with a 4kW Nd:YAG laser and the impact resistance of the alloys was investigated. The alloying powders were a mixture of Ni, Ti and SiC in different proportions. Surfaces reinforced...

  2. Shape rheocasting of high purity aluminium

    CSIR Research Space (South Africa)

    Curle, UA

    2011-03-01

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

  3. Generation and characterization of nano aluminium powder ...

    Indian Academy of Sciences (India)

    TECS

    as a combustion product. This could be useful in reduced smoke applications, since the visibility ... combustion instability due to appropriate particulate damping. A low concentration of regular-sized aluminium ... tance and L the contribution by the internal inductance of the capacitor and the lead inductance. The basic circuit.

  4. Dissolution of aluminium-cladded fuel elements

    International Nuclear Information System (INIS)

    Bernhard, G.; Boessert, W.; Hladik, O.; Schwarzbach, R.

    1984-01-01

    In the molybdenum production plant at Rossendorf (AMOR) short-term irradiated aluminium-cladded fuel elements from the Rossendorf research reactor RFR are dissolved for the purpose of molybdenum 99 production. The dissolution behaviour of these fuel elements and the appropriate dissolver are described. (author)

  5. COMBINED ALUMINIUM SULFATE/HYDROXIDE PROCESS FOR ...

    African Journals Online (AJOL)

    process has higher fluoride removal efficiency than the Nalgonda Technique with an additional advantage of minimizing ... disadvantages of this technique include high residual aluminium concentration (2–7 mg/L) in the treated ... thermogravimetric analyzer (Mettler Toledo AG–TGA/SDTA851e, Switzerland) using ceramic.

  6. Molecular breeding of cereals for aluminium resistance

    Science.gov (United States)

    Aluminium (Al3+) toxicity is the primary factor limiting crop production on acidic soils worldwide. In addition to an application of lime for soil amelioration, Al3+ resistant plant varieties have been deployed to raise productivity on such hostile soils. This has been possible due to the exploita...

  7. Improving mechanical properties of aluminium alloy through ...

    African Journals Online (AJOL)

    This paper investigates the microstructure and mechanical properties of aluminum alloy (Al-Si-Fe) reinforced with coconut shell-ash particulate. The aluminium (Al-Si-Fe) alloy composite was produced by a double-stir casting process at a speed of 700 rpm for 10 and 5 minutes at first and second stirring respectively.

  8. Creep properties of aluminium processed by ECAP

    Czech Academy of Sciences Publication Activity Database

    Král, Petr; Dvořák, Jiří; Jäger, Aleš; Kvapilová, Marie; Horita, Z.; Sklenička, Václav

    2016-01-01

    Roč. 54, č. 6 (2016), s. 441-451 ISSN 0023-432X R&D Projects: GA MŠk(CZ) LQ1601 Institutional support: RVO:68081723 ; RVO:68378271 Keywords : equal channel angular pressing (ECAP) * aluminium * ultrafine-grained microstructure * creep Subject RIV: JG - Metallurgy; JG - Metallurgy (FZU-D) Impact factor: 0.366, year: 2016

  9. Constant structure creep experiments on aluminium

    Czech Academy of Sciences Publication Activity Database

    Milička, Karel

    2011-01-01

    Roč. 49, č. 5 (2011), s. 307-318 ISSN 0023-432X R&D Projects: GA AV ČR IAA2041203 Institutional research plan: CEZ:AV0Z20410507 Keywords : mechanical properties * high temperature deformation * creep * aluminium Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.451, year: 2011

  10. Design of Indium Arsenide nanowire sensors for pH and biological sensing and low temperature transport through p-doped Indium Arsenide nanowires

    DEFF Research Database (Denmark)

    Upadhyay, Shivendra

    remains the primary material of choice. This research is about investigating Indium Arsenide nanowires as alternative platform for sensing charged species - chemical and biological, in solution. Starting with nanowires grown via molecular beam epitaxy in an ultra-high vacuum chamber, we discuss......H sensing, we apply the same to a more complex system - proteins. The sensing protocol involves the functionalization of the sensor surface with a receptor protein followed by the addition of the protein of interest. Sensor response to oppositely charged proteins is used to confirm the sensitivity...... of the sensor to the protein charge....

  11. Optimal power settings of aluminum gallium arsenide lasers in caries inhibition ? An in vitro study

    OpenAIRE

    Sharma, Sonali; Hegde, Mithra N; Sadananda, Vandana; Mathews, Blessen

    2016-01-01

    Context: Incipient carious lesions are characterized by subsurface dissolution due to more fluoride ions in the 50-100 microns of the tooth′s outer surface. Aims: To determine an optimal power setting for 810 nm aluminum gallium arsenide laser for caries inhibition. Materials and Methods: Fifty-four caries-free extracted teeth were sectioned mesiodistally. The samples were divided into 18 groups for each power setting being evaluated. Each group had six samples. The laser used is 810 n...

  12. An advanced space photovoltaic concentrator array using Fresnel lenses, gallium arsenide cells, and prismatic cell covers

    Science.gov (United States)

    O'Neill, Mark J.; Piszczor, Michael F.

    1988-01-01

    The current status of a space concentrator array which uses refractive optics, gallium arsenide cells, and prismatic cell covers to achieve excellent performance at a very low array mass is documented. The prismatically covered cells have established records for space cell performance (24.2 percent efficient at 100 AM0 suns and 25 C) and terrestrial single-junction cell performance (29.3 percent efficient at 200 AM1.5 suns and 25 C).

  13. Changes in gallium arsenide composition near surface under bombardment by Ar+ ions

    International Nuclear Information System (INIS)

    Bert, N.A.; Konnikov, S.G.; Korol'kov, A.V.; Pogrebitskij, K.Yu.

    1988-01-01

    Experimental data on changes in gallium arsenide chemical composition near surface under bombardment by Ar + ions with 5 keV energy are presented. It is shown that in the process described changes are observed in the chemical composition near surface, which result in formation of neighbouring regions with the ratios X Ga /X As >1 and X Ga /X As <1. This phenomenon may have important consequences when using ion beam processing in different technological methods and diagnostics

  14. Performance of a Medipix3RX spectroscopic pixel detector with a high resistivity gallium arsenide sensor.

    Science.gov (United States)

    Hamann, Elias; Koenig, Thomas; Zuber, Marcus; Cecilia, Angelica; Tyazhev, Anton; Tolbanov, Oleg; Procz, Simon; Fauler, Alex; Baumbach, Tilo; Fiederle, Michael

    2015-03-01

    High resistivity gallium arsenide is considered a suitable sensor material for spectroscopic X-ray imaging detectors. These sensors typically have thicknesses between a few hundred μm and 1 mm to ensure a high photon detection efficiency. However, for small pixel sizes down to several tens of μm, an effect called charge sharing reduces a detector's spectroscopic performance. The recently developed Medipix3RX readout chip overcomes this limitation by implementing a charge summing circuit, which allows the reconstruction of the full energy information of a photon interaction in a single pixel. In this work, we present the characterization of the first Medipix3RX detector assembly with a 500 μm thick high resistivity, chromium compensated gallium arsenide sensor. We analyze its properties and demonstrate the functionality of the charge summing mode by means of energy response functions recorded at a synchrotron. Furthermore, the imaging properties of the detector, in terms of its modulation transfer functions and signal-to-noise ratios, are investigated. After more than one decade of attempts to establish gallium arsenide as a sensor material for photon counting detectors, our results represent a breakthrough in obtaining detector-grade material. The sensor we introduce is therefore suitable for high resolution X-ray imaging applications.

  15. Epitaxial lift-off process for gallium arsenide substrate reuse and flexible electronics.

    Science.gov (United States)

    Cheng, Cheng-Wei; Shiu, Kuen-Ting; Li, Ning; Han, Shu-Jen; Shi, Leathen; Sadana, Devendra K

    2013-01-01

    Epitaxial lift-off process enables the separation of III-V device layers from gallium arsenide substrates and has been extensively explored to avoid the high cost of III-V devices by reusing the substrates. Conventional epitaxial lift-off processes require several post-processing steps to restore the substrate to an epi-ready condition. Here we present an epitaxial lift-off scheme that minimizes the amount of post-etching residues and keeps the surface smooth, leading to direct reuse of the gallium arsenide substrate. The successful direct substrate reuse is confirmed by the performance comparison of solar cells grown on the original and the reused substrates. Following the features of our epitaxial lift-off process, a high-throughput technique called surface tension-assisted epitaxial lift-off was developed. In addition to showing full wafer gallium arsenide thin film transfer onto both rigid and flexible substrates, we also demonstrate devices, including light-emitting diode and metal-oxide-semiconductor capacitor, first built on thin active layers and then transferred to secondary substrates.

  16. Two years of on-orbit gallium arsenide performance from the LIPS solar cell panel experiment

    Science.gov (United States)

    Francis, R. W.; Betz, F. E.

    1985-01-01

    The LIPS on-orbit performance of the gallium arsenide panel experiment was analyzed from flight operation telemetry data. Algorithms were developed to calculate the daily maximum power and associated solar array parameters by two independent methods. The first technique utilizes a least mean square polynomial fit to the power curve obtained with intensity and temperature corrected currents and voltages; whereas, the second incorporates an empirical expression for fill factor based on an open circuit voltage and the calculated series resistance. Maximum power, fill factor, open circuit voltage, short circuit current and series resistance of the solar cell array are examined as a function of flight time. Trends are analyzed with respect to possible mechanisms which may affect successive periods of output power during 2 years of flight operation. Degradation factors responsible for the on-orbit performance characteristics of gallium arsenide are discussed in relation to the calculated solar cell parameters. Performance trends and the potential degradation mechanisms are correlated with existing laboratory and flight data on both gallium arsenide and silicon solar cells for similar environments.

  17. Aluminium in brain tissue in familial Alzheimer's disease.

    Science.gov (United States)

    Mirza, Ambreen; King, Andrew; Troakes, Claire; Exley, Christopher

    2017-03-01

    The genetic predispositions which describe a diagnosis of familial Alzheimer's disease can be considered as cornerstones of the amyloid cascade hypothesis. Essentially they place the expression and metabolism of the amyloid precursor protein as the main tenet of disease aetiology. However, we do not know the cause of Alzheimer's disease and environmental factors may yet be shown to contribute towards its onset and progression. One such environmental factor is human exposure to aluminium and aluminium has been shown to be present in brain tissue in sporadic Alzheimer's disease. We have made the first ever measurements of aluminium in brain tissue from 12 donors diagnosed with familial Alzheimer's disease. The concentrations of aluminium were extremely high, for example, there were values in excess of 10μg/g tissue dry wt. in 5 of the 12 individuals. Overall, the concentrations were higher than all previous measurements of brain aluminium except cases of known aluminium-induced encephalopathy. We have supported our quantitative analyses using a novel method of aluminium-selective fluorescence microscopy to visualise aluminium in all lobes of every brain investigated. The unique quantitative data and the stunning images of aluminium in familial Alzheimer's disease brain tissue raise the spectre of aluminium's role in this devastating disease. Copyright © 2016 The Authors. Published by Elsevier GmbH.. All rights reserved.

  18. Toxicity of dissolved and precipitated aluminium to marine diatoms.

    Science.gov (United States)

    Gillmore, Megan L; Golding, Lisa A; Angel, Brad M; Adams, Merrin S; Jolley, Dianne F

    2016-05-01

    Localised aluminium contamination can lead to high concentrations in coastal waters, which have the potential for adverse effects on aquatic organisms. This research investigated the toxicity of 72-h exposures of aluminium to three marine diatoms (Ceratoneis closterium (formerly Nitzschia closterium), Minutocellus polymorphus and Phaeodactylum tricornutum) by measuring population growth rate inhibition and cell membrane damage (SYTOX Green) as endpoints. Toxicity was correlated to the time-averaged concentrations of different aluminium size-fractions, operationally defined as diatom species. C. closterium was the most sensitive species (10% inhibition of growth rate (72-h IC10) of 80 (55-100)μg Al/L (95% confidence limits)) while M. polymorphus (540 (460-600)μg Al/L) and P. tricornutum (2100 (2000-2200)μg Al/L) were less sensitive (based on measured total aluminium). Dissolved aluminium was the primary contributor to toxicity in C. closterium, while a combination of dissolved and precipitated aluminium forms contributed to toxicity in M. polymorphus. In contrast, aluminium toxicity to the most tolerant diatom P. tricornutum was due predominantly to precipitated aluminium. Preliminary investigations revealed the sensitivity of C. closterium and M. polymorphus to aluminium was influenced by initial cell density with aluminium toxicity significantly (pdiatoms suggesting that mechanisms of aluminium toxicity to diatoms do not involve compromising the plasma membrane. These results indicate that marine diatoms have a broad range in sensitivity to aluminium with toxic mechanisms related to both dissolved and precipitated aluminium. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. [Association between serum aluminium level and methylation of amyloid precursor protein gene in workers engaged in aluminium electrolysis].

    Science.gov (United States)

    Yang, X J; Yuan, Y Z; Niu, Q

    2016-04-20

    To investigate the association between serum aluminium level and methylation of the promoter region of amyloid precursor protein (APP)gene in workers engaged in aluminium electrolysis. In 2012, 366 electrolysis workers in an aluminium factory were enrolled as exposure group (working years >10 and age >40 years)and divided into low-exposure group and high-exposure group based on the median serum aluminium level. Meanwhile, 102 workers in a cement plant not exposed to aluminium were enrolled as control group. Graphite furnace atomic absorption spectrometry was used to measure serum aluminium level, methylation specific PCR was used to measure the methylation rate of the promoter region of APP gene, and ELI-SA was used to measure the protein expression of APP in lymphocytes in peripheral blood. The exposure group had a significantly higher serum aluminium level than the control group (45.07 μg/L vs 30.51 μg/L, P0.05). The multivariate logistic regression analysis showed that with reference to the control group, low aluminium exposure (OR=1.86, 95% CI 1.67~3.52)and high aluminium exposure (OR=2.98, 95% CI 1.97~4.15)were risk factors for a reduced methylation rate of the promoter region of APP gene. Reduced methylation of the promoter region of APP gene may be associated with increased serum aluminium level, and downregulated methylation of the promoter region of APP gene may accelerate APP gene transcription.

  20. Demethylation of Quinine Using Anhydrous Aluminium Trichloride

    Directory of Open Access Journals (Sweden)

    Aiyi Asnawi

    2011-03-01

    Full Text Available Quinine is a natural alkaloid having a methoxy group bound to quinoline ring and an allyl group bound to quinuclidine ring. Demethylation of quinine applying strong acid such as HBr or HI at high temperature was unsuccessful. The aim of this research was to obtain demethylated quinine by means of mild and selective demethylation procedure to prevent the addition reaction of allyl group. Selective demethylation of quinine has been carried out using anhydrous aluminium trichloride as reagent. The demethylation product was achieved in 68.12% yield by mole ratio of quinine to anhydrous aluminium trichloride of 1 to 4 in dried methylene chloride under nitrogen atmosphere. The reaction was firstly carried out at 0°C for 4 h and after the reaction mixture reached room temperature, the reaction was continued up to 24 h.

  1. Diagnostics of ytterbium/aluminium laser plasmas

    International Nuclear Information System (INIS)

    Bailey, J.; Lee, R.W.; Landen, O.L.; Kilkenny, J.D.; Lewis, C.L.; Busquet, M.

    1986-11-01

    Microdot spectroscopy was used to study the x-ray emission from laser-produced plasmas consisting of 10% ytterbium, 90% aluminium. Spectra were recorded with a space-resolving flat crystal (PET) mini-spectrometer in the 4.0-8.0 A range. The Janus research laser at LLNL irradiated the targets with green (0.53 μm) light in a 1 nsec pulse. The power density was varied between 4x10 13 and 3x10 14 W/cm 2 . The plasma electron density and temperature were determined from the aluminium XI, XII and XIII line emission. By examining correlations between changes in the plasma conditions with changes in the ytterbium spectra, we will determine the potential for using ytterbium line emission as a plasma diagnostic

  2. ALUHAB — The Superior Aluminium Foam

    Science.gov (United States)

    Babcsan, N.; Beke, S.; Makk, P.; Soki, P.; Számel, Gy; Degischer, H. P.; Mokso, R.

    A new metal foaming technology has been developed to produce aluminum foams with controlled cell sizes, a wide range of alloy compositions, and attractive mechanical properties. ALUHAB aluminium foams are manufactured from a special foamable aluminium alloy containing ultrafine particles (80-3000 nm). The technology uses high temperature ultrasonication to homogeneously disperse the particles and thus create a stable, foamable aluminum melt. Oscillating gas injector (loud-nozzle) technology permits the injection of optimally sized bubbles into the melt that are independent of the injector orifice diameter. Using this direct gas injection method, bubble size is regulated by the frequency and the power of the ultrasound, producing uniform bubble sizes in the sub-millimeter range. The technology results in extremely stable metal foams which can be cast into complex forms and re-melted without loss of foam integrity. Processing methods and properties of the ALUHAB foams will be discussed.

  3. Melt spun aluminium alloys for moulding optics

    Science.gov (United States)

    Gubbels, G.; Tegelaers, L.; Senden, R.

    2013-09-01

    Melt spinning is a rapid quenching process that makes it possible to create materials with a very fine microstructure. Due to this very fine microstructure the melt spinning process is an enabler for diamond turning optics and moulds without the need of post-polishing. Using diamond turning of melt spun aluminium one can achieve coating concept RSA-905 can be upgraded to a competitive alternative to steel in terms of price, performance and logistics. This paper presents some recent developments for improved mould performance of such concept. Hardness, wear resistance and adhesion are topics of interest and they can be applied by special coatings such as diamond-like carbon (DLC) and chromium nitride (CrN). These coatings make the aluminium alloy suitable for moulding mass production of small as well as larger optics, such as spectacle lenses.

  4. Feet sunk in molten aluminium: The burn and its prevention.

    Science.gov (United States)

    Alonso-Peña, David; Arnáiz-García, María Elena; Valero-Gasalla, Javier Luis; Arnáiz-García, Ana María; Campillo-Campaña, Ramón; Alonso-Peña, Javier; González-Santos, Jose María; Fernández-Díaz, Alaska Leonor; Arnáiz, Javier

    2015-08-01

    Nowadays, despite improvements in safety rules and inspections in the metal industry, foundry workers are not free from burn accidents. Injuries caused by molten metals include burns secondary to molten iron, aluminium, zinc, copper, brass, bronze, manganese, lead and steel. Molten aluminium is one of the most common causative agents of burns (60%); however, only a few publications exist concerning injuries from molten aluminium. The main mechanisms of lesion from molten aluminium include direct contact of the molten metal with the skin or through safety apparel, or when the metal splash burns through the pants and rolls downward along the leg. Herein, we report three cases of deep dermal burns after 'soaking' the foot in liquid aluminium and its evolutive features. This paper aims to show our experience in the management of burns due to molten aluminium. We describe the current management principles and the key features of injury prevention. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

  5. What is the risk of aluminium as a neurotoxin?

    Science.gov (United States)

    Exley, Christopher

    2014-06-01

    Aluminium is neurotoxic. Its free ion, Al(3+) (aq), is highly biologically reactive and uniquely equipped to do damage to essential cellular (neuronal) biochemistry. This unequivocal fact must be the starting point in examining the risk posed by aluminium as a neurotoxin in humans. Aluminium is present in the human brain and it accumulates with age. The most recent research demonstrates that a significant proportion of individuals older than 70 years of age have a potentially pathological accumulation of aluminium somewhere in their brain. What are the symptoms of chronic aluminium intoxication in humans? What if neurodegenerative diseases such as Alzheimer's disease are the manifestation of the risk of aluminium as a neurotoxin? How might such an (outrageous) hypothesis be tested?

  6. Simulation of aluminium STIR casting technique

    International Nuclear Information System (INIS)

    Hafizal Yazid; Mohd Harun; Hanani Yazid; Abd Aziz Mohamed; Muhammad Rawi Muhammad Zain; Zaiton Selamat; Mohd Shariff Sattar; Muhamad Jalil; Ismail Mustapha; Razali Kasim

    2006-01-01

    In this paper, the objective is to determine the optimum impeller speed correlated with holding time to achieve homogeneous reinforcement distribution for a particular set of experimental condition. Attempts are made to simulate the flow behaviourof the liquid aluminium using FLUENT software. Stepwise impeller speed ranging from 50 to 300 rpm.with 2 impeller angle blades of 45 and 90 degree with respect to the rotational plane were used

  7. Aluminium phosphide poising: a case report

    International Nuclear Information System (INIS)

    Hirani, S.A.A.; Rahman, A.

    2010-01-01

    This paper reports the case of a family in which three children were presented at Emergency Room (ER) with poisoning after the use of a pesticide at home. Initially, the cases were managed as routine cases of organophosphorus poisoning; however, the death of two children made the health team members realise that the poison's effects were delayed and devastating. Later, the compound was identified as Aluminium Phosphide (ALP), and the life of the last surviving child in the family was saved. (author)

  8. Helium behaviour in aluminium under hydrostatic pressure

    International Nuclear Information System (INIS)

    Sokurskij, Yu.N.; Tebus, V.N.; Zudilin, V.A.; Tumanova, G.M.

    1989-01-01

    Effect of hydrostatic compression on equilibrium helium bubbles in low aluminium-lithium alloy irradiated in reactor at 570 K is investigated. Measurements of hydrostatic density and electron-microscopic investigations have shown, that application of up to 2 GPa pressure reduces equilibrium size of helium bubbles and reduces helium swelling. Kinetics and thermodynamics of the process are considered with application of 'rigid sphere' equation which describes helium state in bubbles

  9. Swedish research on aluminium reactor technology

    International Nuclear Information System (INIS)

    Forsen, Bjoern

    1960-02-01

    A historical survey of the work done in Sweden this subject is given in the first part of the paper. The second part is elevated to a brief outline of the authors view of the present status of corrosion theories for aluminium in high temperature water. A theory where the crystallization of boehemite from the barrier layer is considered as an important control of the corrosion reaction is presented

  10. Multiply-negatively charged aluminium clusters and fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Noelle

    2008-07-15

    Multiply negatively charged aluminium clusters and fullerenes were generated in a Penning trap using the 'electron-bath' technique. Aluminium monoanions were generated using a laser vaporisation source. After this, two-, three- and four-times negatively charged aluminium clusters were generated for the first time. This research marks the first observation of tetra-anionic metal clusters in the gas phase. Additionally, doubly-negatively charged fullerenes were generated. The smallest fullerene dianion observed contained 70 atoms. (orig.)

  11. Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate

    Directory of Open Access Journals (Sweden)

    B. Bobic

    2010-03-01

    Full Text Available The corrosion behaviour of MMCs with aluminium alloy matrix was presented. The corrosion characteristics of boron-, graphite-, silicon carbide-, alumina- and mica- reinforced aluminium MMCs were reviewed. The reinforcing phase influence on MMCs corrosion rate as well as on various corrosion forms (galvanic, pitting, stress corrosion cracking, corrosion fatique, tribocorrosion was discussed. Some corrosion protection methods of aluminium based MMCs were described

  12. No risk of Alzheimer's disease from aluminium in consumer products

    OpenAIRE

    German Federal Institute for Risk Assessment

    2007-01-01

    Aluminium is the third most frequent element in the earth's crust and occurs naturally in drinking water and other foods, particularly in fruit and vegetables. For consumers the main uptake route is food. There may be additional exposure from aluminium-containing food-contact articles like kitchen utensils, cans, foils or tubes from which the light metal migrates into the food. Furthermore, aluminium may also be contained in medicinal products to neutralise gastric acid, so-called antacids an...

  13. The aluminium content of infant formulas remains too high.

    Science.gov (United States)

    Chuchu, Nancy; Patel, Bhavini; Sebastian, Blaise; Exley, Christopher

    2013-10-08

    Recent research published in this journal highlighted the issue of the high content of aluminium in infant formulas. The expectation was that the findings would serve as a catalyst for manufacturers to address a significant problem of these, often necessary, components of infant nutrition. It is critically important that parents and other users have confidence in the safety of infant formulas and that they have reliable information to use in choosing a product with a lower content of aluminium. Herein, we have significantly extended the scope of the previous research and the aluminium content of 30 of the most widely available and often used infant formulas has been measured. Both ready-to-drink milks and milk powders were subjected to microwave digestion in the presence of 15.8 M HNO3 and 30% w/v H2O2 and the aluminium content of the digests was measured by TH GFAAS. Both ready-to-drink milks and milk powders were contaminated with aluminium. The concentration of aluminium across all milk products ranged from ca 100 to 430 μg/L. The concentration of aluminium in two soya-based milk products was 656 and 756 μg/L. The intake of aluminium from non-soya-based infant formulas varied from ca 100 to 300 μg per day. For soya-based milks it could be as high as 700 μg per day. All 30 infant formulas were contaminated with aluminium. There was no clear evidence that subsequent to the problem of aluminium being highlighted in a previous publication in this journal that contamination had been addressed and reduced. It is the opinion of the authors that regulatory and other non-voluntary methods are now required to reduce the aluminium content of infant formulas and thereby protect infants from chronic exposure to dietary aluminium.

  14. Improving the Crashworthiness of Aluminium Rail Vehicles

    Science.gov (United States)

    Zangani, Donato; Robinson, Mark; Kotsikos, George

    An experimental and modelling programme of work have been undertaken to predict the performance of aluminium welds in rail vehicles under highly dynamic loading conditions and provide design guidelines to reduce the likelihood of the occurrence of weld unzipping. Modelling of weld unzipping in large rail structures is a challenging task since it requires to deal with material instability, to take into account the uncertainties in material parameters and to address the problem of mesh resolution which together pose severe challenges to computability. The proposed methodology to the prediction of weld failure is based on the validation of the numerical models through correlation with laboratory scale tearing tests. The tearing tests were conducted on samples taken from real rail extrusions with the purpose of obtaining the failure parameters under dynamic loading and understanding the effect of weld material composition on joint behaviour. The validated material models were used to construct a FEA simulation of the collision of an aluminium rail car and investigate the effect of both joint geometry and welding techniques on the failure mechanism. Comparisons of the model with the failures observed in an aluminium rail vehicle that was involved in a high speed collision, have shown that it is possible to model the phenomenon of weld unzipping with good accuracy. The numerical models have also been used as a tool for the optimisation of joint design to improve crashworthiness.

  15. Aluminium in the rail transportation market

    Energy Technology Data Exchange (ETDEWEB)

    Zehnder, J. [Alcan Alesa Engineering Ltd., Zurich (Switzerland). Alcan Mass Transportation Systems

    2002-07-01

    Rail-transportation is not, as one might expect, a homogeneous market but extremely fragmented and even with huge differences from continent to continent, i.e. in North America freight transport is dominating whereas in Europe passenger transport prevails. A first segmentation splits infrastructure from vehicles. In a second layer of segmentation we distinguish between light rail vehicles, heavy metros, regional trains, intercity trains, high speed trains with and without tilting, maglev trains, freight vehicles and locomotives. Finally, we find aluminium applications in wheels, suspension parts, brake equipment, traction equipment, body structure, hang on parts and interior trim. On the infrastructure side best use of aluminium is in the field of power supply. In order to have the best solution for each application, all forms of products such as castings, forgings, flat rolled products and extrusions are needed and the engineers are using a broad choice or different alloys for all the requirements such as structural strength, decorative aspect, electrical conductivity, wear resistance, weldability, corrosion resistance etc. Innovation cycles in rail transportation are very slow, mainly because the expected life of vehicles is over 30 years and so no fleet owner will run the risk of getting vehicles with non-proven components, i.e. where a safe life of over 30 years cannot be shown. In the following the most important aluminium applications are shown and discussed. (orig.)

  16. Friction stir welding (FSW of aluminium foam sandwich panels

    Directory of Open Access Journals (Sweden)

    M. Bušić

    2016-07-01

    Full Text Available The article focuses on the influence of welding speed and tool tilt angle upon the mechanical properties at the friction stir welding of aluminium foam sandwich panels. Double side welding was used for producing butt welds of aluminium sandwich panels applying insertion of extruded aluminium profile. Such insertion provided lower pressure of the tool upon the aluminium panels, providing also sufficient volume of the material required for the weldment formation. Ultimate tensile strength and flexural strength for three-point bending test have been determined for samples taken from the welded joints. Results have confirmed anticipated effects of independent variables.

  17. Numerical predicting of recycling friendly wrought aluminium alloy compositions

    Directory of Open Access Journals (Sweden)

    Varužan Kevorkijan

    2013-09-01

    Full Text Available The model presented in this work enables the design of optimal (standard and non-standard “recycling-friendly” compositions and properties of wrought aluminium alloys with significantly increased amounts of post-consumed scrap. The following two routes were modelled in detail: (i the blending of standard and non-standard compositions of wrought aluminium alloys starting from post-consumed aluminium scrap sorted to various degrees simulated by the model; and (ii changing the initial standard composition of wrought aluminium alloys to non-standard “recycling friendly” ones - with broader concentration tolerance limits of alloying elements, without influencing the selected alloy properties, specified in advance.

  18. Investigation process of alcoholysis of hydride aluminium-adobe

    International Nuclear Information System (INIS)

    Numanov, M.I.; Normatov, I.Sh.; Mirsaidov, U.M.

    2001-01-01

    Considering of that process of acid treatment of aluminium-adobe hydride realizes in the ethyl alcohol media it was necessary study the process of alcoholysis of AlH 3 and aluminium additives. In the end of article authors became to conclusion that deficiency of spontaneous alcoholysis of AlH 3 in adobe caused by protective action of fiber; solvate ability of LiCl and alkoxy aluminium hydride of lithium-LiCl·CO 2 H 5 OH, Li Al(OC 2 H 5 ) 4 ·nC 2 H 5 OH decreasing the expectancy of responding of alcohol with aluminium hydride

  19. Serum aluminium levels of workers in the bauxite mines.

    Science.gov (United States)

    de Kom, J F; Dissels, H M; van der Voet, G B; de Wolff, F A

    1997-01-01

    Aluminium is produced from the mineral bauxite. Occupational exposure is reported during the industrial processing of aluminium and is associated with pulmonary and neurotoxicity. However, data on exposure and toxicity of workers in the open bauxite mining industry do not exist. Therefore, a study was performed to explore aluminium exposure in employees involved in this bauxite mining process in a Surinam mine. A group of workers occupationally exposed to aluminium in an open bauxite mine were compared with a group of nonexposed wood processors. Serum aluminium was analyzed using atomic absorption spectrometry Data from the clinical chemistry of the blood and a questionnaire were used to explore determinants for aluminium exposure. No significant difference between serum aluminium in the exposed (4.4 +/- 2.0 micrograms/L, n = 27) and control group (5.1 +/- 1.5 micrograms/L, n = 27) was detected. For the serum concentration of the clinical chemical variables (calcium, citrate, and creatinine), a statistically significant difference was computed (p < or = 0.02) between the exposed and control group. All levels were slightly higher in the exposed group; no statistically significant correlations with serum aluminium were found. In this study, serum aluminium values were in the normal range, no significant difference between the groups could be detected despite long-term occupational exposure.

  20. Trial finds better haemostasis with aluminium chloride during periapical surgery.

    Science.gov (United States)

    Mc Goldrick, Niall; Ross, Carly; Nelson, James

    2017-06-23

    DesignRandomised controlled trial in a university setting.InterventionPatients were randomised to epinephrine impregnated gauze or aluminium chloride for periapical surgery involving a single tooth with a periapical area of aluminium chloride group were analysed. Adequate haemostasis was achieved in 25 (52.1%) of the epinephrine group and 37 (72.5%) of the aluminium chloride group, a statistically significant difference.ConclusionsThe outcome showed better efficacy of haemostasis in the aluminium chloride group than in the gauze impregnated epinephrine group. The analysis of the patients and tooth-dependent variables showed no relationship with the effectiveness of haemostasis.

  1. Determination of Aluminium Content in Aluminium Hydroxide Formulation by FT-NIR Transmittance Spectroscopy

    DEFF Research Database (Denmark)

    Lai, Xuxin; Zheng, Yiwu; Søndergaard, Ib

    2007-01-01

    A method for determining the aluminium content of an aluminium hydroxide suspension using near infrared (NIR) transmittance spectroscopy has been developed. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) was used as reference method. The factors influencing the NIR analysis......-AES and NIR transmittance spectroscopy exhibit comparable precision and accuracy. The NIR method provides several advantages: no complicated sample preparation; easy to operate; fast and non-destructive. In conclusion, NIR transmittance spectroscopy can be an alternative analytical method for determining...

  2. Effect of barrier height on friction behavior of the semiconductors silicon and gallium arsenide in contact with pure metals

    Science.gov (United States)

    Mishina, H.; Buckley, D. H.

    1984-01-01

    Friction experiments were conducted for the semiconductors silicon and gallium arsenide in contact with pure metals. Polycrystalline titanium, tantalum, nickel, palladium, and platinum were made to contact a single crystal silicon (111) surface. Indium, nickel, copper, and silver were made to contact a single crystal gallium arsenide (100) surface. Sliding was conducted both in room air and in a vacuum of 10 to the minus 9th power torr. The friction of semiconductors in contact with metals depended on a Schottky barrier height formed at the metal semiconductor interface. Metals with a higher barrier height on semiconductors gave lower friction. The effect of the barrier height on friction behavior for argon sputtered cleaned surfaces in vacuum was more specific than that for the surfaces containing films in room air. With a silicon surface sliding on titanium, many silicon particles back transferred. In contrast, a large quantity of indium transferred to the gallium arsenide surface.

  3. A new synthesis process for aluminium nitride. Nouveau procede de synthese du nitrure d'aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Haussonne, J.M. (CNET, Centre Lannion B, 22 (France)); Lostec, J. (CNET, Centre Lannion B, 22 (France)); Bertot, J.P. (CNET, Centre Lannion B, 22 (France)); Lostec, L. (CNET, Centre Lannion B, 22 (France)); Sadou, S. (CNET, Centre Lannion B, 22 (France))

    1993-04-01

    Thermodynamic considerations show that, even at room temperature, pure aluminium can react with nitrogen to form the aluminium nitride AlN. However, pure aluminium does not exist: it is always surrounded by an alumina shell that protects the metal from further reactions. Furthermore, in the hypothesis where one has been able to make aluminium react with nitrogen, an aluminium nitride shell will protect as well the metal core from further oxidation. Prompted by the Lanxide process allowing to form Al/Al[sub 2]O[sub 3] composites, we have mixed aluminium powders with lithium salts, and easily synthesized pure aluminium nitride by heating the mixed powders in nitrigen at temperatures ranging from 800 to 1200 C. Starting from aluminium powders with a specific area ranging from 0.3 to 4 m[sup 2]/g, we have been able to produce aluminium nitride with specific are ranging from 1 to 20 m[sup 2]/g. Mixed with Y[sub 2]O[sub 3]-CaO and sintered at 1720 C in N[sub 2], we obtained AlN ceramics owning 92% density and 160 W/m.K thermal conductivity. (orig.).

  4. There is (still too much aluminium in infant formulas

    Directory of Open Access Journals (Sweden)

    Burrell Shelle-Ann M

    2010-08-01

    Full Text Available Abstract Background Infant formulas are sophisticated milk-based feeds for infants which are used as a substitute for breast milk. Historically they are known to be contaminated by aluminium and in the past this has raised health concerns for exposed infants. We have measured the aluminium content of a number of widely used infant formulas to determine if their contamination by aluminium and consequent issues of child health persists. Methods Samples of ready-made milks and powders used to make milks were prepared by microwave digestion of acid/peroxide mixtures and their aluminium content determined by THGA. Results The concentration of aluminium in ready-made milks varied from ca 176 to 700 μg/L. The latter concentration was for a milk for preterm infants. The aluminium content of powders used to make milks varied from ca 2.4 to 4.3 μg/g. The latter content was for a soya-based formula and equated to a ready-to-drink milk concentration of 629 μg/L. Using the manufacturer's own guidelines of formula consumption the average daily ingestion of aluminium from infant formulas for a child of 6 months varied from ca 200 to 600 μg of aluminium. Generally ingestion was higher from powdered as compared to ready-made formulas. Conclusions The aluminium content of a range of well known brands of infant formulas remains high and particularly so for a product designed for preterm infants and a soya-based product designed for infants with cow's milk intolerances and allergies. Recent research demonstrating the vulnerability of infants to early exposure to aluminium serves to highlight an urgent need to reduce the aluminium content of infant formulas to as low a level as is practically possible.

  5. Long-term effects of aluminium dust inhalation.

    Science.gov (United States)

    Peters, Susan; Reid, Alison; Fritschi, Lin; de Klerk, Nicholas; Musk, A W Bill

    2013-12-01

    During the 1950s and 1960s, aluminium dust inhalation was used as a potential prophylaxis against silicosis in underground miners, including in Australia. We investigated the association between aluminium dust inhalation and cardiovascular, cerebrovascular and Alzheimer's diseases in a cohort of Australian male underground gold miners. We additionally looked at pneumoconiosis mortality to estimate the effect of the aluminium therapy. SMRs and 95% CI were calculated to compare mortality of the cohort members with that of the Western Australian male population (1961-2009). Internal comparisons on duration of aluminium dust inhalation were examined using Cox regression. Aluminium dust inhalation was reported for 647 out of 1894 underground gold miners. During 42 780 person-years of follow-up, 1577 deaths were observed. An indication of increased mortality of Alzheimer's disease among miners ever exposed to aluminium dust was found (SMR=1.38), although it was not statistically significant (95% CI 0.69 to 2.75). Rates for cardiovascular and cerebrovascular death were above population levels, but were similar for subjects with or without a history of aluminium dust inhalation. HRs suggested an increasing risk of cardiovascular disease with duration of aluminium dust inhalation (HR=1.02, 95% CI 1.00 to 1.04, per year of exposure). No difference in the association between duration of work underground and pneumoconiosis was observed between the groups with or without aluminium dust exposure. No protective effect against silicosis was observed from aluminium dust inhalation. Conversely, exposure to aluminium dust may possibly increase the risk of cardiovascular disease and dementia of the Alzheimer's type.

  6. Effect of gallium-arsenide laser, gallium-aluminum-arsenide laser and healing ointment on cutaneous wound healing in Wistar rats

    Directory of Open Access Journals (Sweden)

    R.V. Gonçalves

    2010-04-01

    Full Text Available This study determined the effects of gallium-aluminum-arsenide laser (GaAlAs, gallium-arsenide laser (GaAs and Dersani® healing ointment on skin wounds in Wistar rats. The parameters analyzed were: type I and III collagen fiber concentrations as well as the rate of wound closure. Five wounds, 12 mm in diameter, were made on the animals’ backs. The depth of the surgical incision was controlled by removing the epithelial tissue until the dorsal muscular fascia was exposed. The animals were anesthetized with ketamine and xylazine via intraperitoneal injection. The rats were randomly divided into five groups of 6 animals each, according to the treatment received. Group 1 (L4: GaAs laser (4 J/cm²; group 2 (L30: GaAlAs laser (30 J/cm²; group 3 (L60: GaAlAs laser (60 J/cm²; group 4 (D: Dersani® ointment; group 5 (control: 0.9% saline. The applications were made daily over a period of 20 days. Tissue fragments were stained with picrosirius to distinguish type I collagen from type III collagen. The collagen fibers were photo-documented and analyzed using the Quantum software based on the primary color spectrum (red, yellow and blue. Significant results for wound closing rate were obtained for group 1 (L4, 7.37 mm/day. The highest concentration of type III collagen fibers was observed in group 2 (L30; 37.80 ± 7.10%, which differed from control (29.86 ± 5.15% on the 20th day of treatment. The type I collagen fibers of group 1 (L4; 2.67 ± 2.23% and group 2 (L30; 2.87 ± 2.40% differed significantly from control (1.77 ± 2.97% on the 20th day of the experiment.

  7. Effect of gallium-arsenide laser, gallium-aluminum-arsenide laser and healing ointment on cutaneous wound healing in Wistar rats.

    Science.gov (United States)

    Gonçalves, R V; Mezêncio, J M S; Benevides, G P; Matta, S L P; Neves, C A; Sarandy, M M; Vilela, E F

    2010-04-01

    This study determined the effects of gallium-aluminum-arsenide laser (GaAlAs), gallium-arsenide laser (GaAs) and Dersani healing ointment on skin wounds in Wistar rats. The parameters analyzed were: type I and III collagen fiber concentrations as well as the rate of wound closure. Five wounds, 12 mm in diameter, were made on the animals' backs. The depth of the surgical incision was controlled by removing the epithelial tissue until the dorsal muscular fascia was exposed. The animals were anesthetized with ketamine and xylazine via intraperitoneal injection. The rats were randomly divided into five groups of 6 animals each, according to the treatment received. Group 1 (L4): GaAs laser (4 J/cm(2)); group 2 (L30): GaAlAs laser (30 J/cm(2)); group 3 (L60): GaAlAs laser (60 J/cm(2)); group 4 (D): Dersani ointment; group 5 (control): 0.9% saline. The applications were made daily over a period of 20 days. Tissue fragments were stained with picrosirius to distinguish type I collagen from type III collagen. The collagen fibers were photo-documented and analyzed using the Quantum software based on the primary color spectrum (red, yellow and blue). Significant results for wound closing rate were obtained for group 1 (L4), 7.37 mm/day. The highest concentration of type III collagen fibers was observed in group 2 (L30; 37.80 + or - 7.10%), which differed from control (29.86 + or - 5.15%) on the 20th day of treatment. The type I collagen fibers of group 1 (L4; 2.67 + or - 2.23%) and group 2 (L30; 2.87 + or - 2.40%) differed significantly from control (1.77 + or - 2.97%) on the 20th day of the experiment.

  8. Comparative study of the toxic effects of gallium arsenide, indium arsenide and arsenic trioxide following intratracheal instillations to the lung of Syrian golden hamsters.

    Science.gov (United States)

    Tanaka, A; Hirata, M; Omura, M; Zhao, M; Makita, Y; Yamazaki, K; Inoue, N; Gotoh, K

    2000-01-01

    Toxic effects of gallium arsenide (GaAs), indium arsenide (InAs) and arsenic trioxide (As2O3) were studied in male Syrian golden hamsters. GaAs (7.7 mg/kg) and As2O3 (1.3 mg/kg) particles were instilled intratracheally twice a week a total of 16 times, while InAs (7.7 mg/kg) was instilled a total of 14 times. As a control, hamsters were treated with the vehicle, phosphate buffer solution. During the instillation period, the cumulative body weight gain of the InAs-, but not the GaAs- or As2O3-treated hamsters was suppressed significantly, when compared with the control group. Slight to severe inflammatory responses were observed in the lung for all treatment groups. The most severe inflammatory change, characterized by an accumulation of neutrophils and macrophages, exudation, thickness of the pleura and fibrotic proliferation was found in the InAs-treated hamsters. Extensive alveolar or bronchiolar cell hyperplasia with or without keratinizing squamous cell metaplasia was observed in almost all the InAs-treated hamsters. Furthermore, squamous cell metaplasia or squamous cell hyperplasia developed in some of the InAs-treated hamsters, but not in the GaAs- or As2O3-treated hamsters. Slight to mild lesions were found in the convoluted tubules of the kidney in both the GaAs and InAs groups. From the present study, the toxic potency of these particles was provisionally estimated to be in the following order: InAs > GaAs > As2O3, at the dosage level used in this study. Furthermore, there was evidence that InAs particles could induce pulmonary, renal or systemic toxicity, and as such, InAs particles may produce pulmonary precancerous change when instilled intratracheally into hamsters.

  9. The metabolism of inorganic arsenic oxides, gallium arsenide, and arsine: a toxicochemical review

    International Nuclear Information System (INIS)

    Carter, Dean E.; Aposhian, H. Vasken; Gandolfi, A. Jay

    2003-01-01

    The aim of this review is to compare the metabolism, chemistry, and biological effects to determine if either of the industrial arsenicals (arsine and gallium arsenide) act like the environmental arsenic oxides (arsenite and arsenate). The metabolism of the arsenic oxides has been extensively investigated in the past 4 years and the differences between the arsenic metabolites in the oxidation states +III versus +V and with one or two methyl groups added have shown increased importance. The arsenic oxide metabolism has been compared with arsine (oxidation state -III) and arsenide (oxidation state between 0 to -III). The different metabolites appear to have different strengths of reaction for binding aresenic (III) to thiol groups, their oxidation-reduction reactions and their forming an arsenic-carbon bond. It is unclear if the differences in parameters such as the presence or absence of methyl metabolities, the rates of AsV reduction compared to the rates of AsIII oxidation, or the competition of phosphate and arsenate for cellular uptake are large enough to change biological effects. The arsine rate of decomposition, products of metabolism, target organ of toxic action, and protein binding appeared to support an oxidized arsenic metabolite. This arsine metabolite was very different from anything made by the arsenic oxides. The gallium arsenide had a lower solubility than any other arsenic compound and it had a disproportionate intensity of lung damage to suggest that the GaAs had a site of contact interaction and that oxidation reactions were important in its toxicity. The urinary metabolites after GaAs exposure were the same as excreted by arsenic oxides but the chemical compounds responsible for the toxic effects of GaAs are different from the aresnic oxides. The review concludes that there is insufficient evidence to equate the different arsenic compounds. There are several differences in the toxicity of the arsenic compounds that will require substantial

  10. Aluminium and iron air pollution near an iron casting and aluminium foundry in Turin district (Italy).

    Science.gov (United States)

    Polizzi, Salvatore; Ferrara, Mauro; Bugiani, Massimiliano; Barbero, Domenico; Baccolo, Tiziana

    2007-09-01

    This work reports the results of an environmental survey carried out in an industrial area in the Province of Turin: its main aim is to assess the levels of iron and aluminium in the outside air during the period from July to September to assess the influence of industrial activity (a cast-iron and aluminium foundry) which is interrupted during the month of August, on the level of metals present in the air. Conducting the analysis during this period of time made it possible to avoid the confounding effect of pollution due to domestic central heating. The measurements were taken from nine areas at different distances from the foundry in the area and according to the direction of the prevailing winds, as deduced from the historical data. The results of this survey show a statistically significant difference in iron and aluminium levels in the outside air in the geographic areas between the two main periods examined: during August (no foundry activity) v/s July-September (foundry activity). The values recorded are: Aluminium 0.4+/-0.45 microg/m(3) v/s 1.12+/-1.29 microg/m(3) (pIron 0.95+/-0.56 microg/m(3) v/s 1.6+/-1.0 microg/m(3) (piron tended to be higher in the areas farther away from the foundry site in the areas located along the path of the prevailing winds.

  11. Mechanical properties of plasma-sprayed layers of aluminium and aluminium alloy on AZ 91

    Czech Academy of Sciences Publication Activity Database

    Kubatík, Tomáš František; Ctibor, Pavel; Mušálek, Radek; Janata, Marek

    2017-01-01

    Roč. 51, č. 2 (2017), s. 323-327 ISSN 1580-2949 R&D Projects: GA ČR(CZ) GP14-31538P Institutional support: RVO:61389021 Keywords : plasma spraying of aluminium * adhesion of coating * wear * magnesium alloy AZ91 Subject RIV: JG - Metallurgy OBOR OECD: Materials engineering Impact factor: 0.436, year: 2016

  12. Speciation analysis of aluminium and aluminium fluoride complexes by HPIC-UVVIS.

    Science.gov (United States)

    Frankowski, Marcin; Zioła-Frankowska, Anetta

    2010-10-15

    The study presents a new analytical method for speciation analysis in fractionation of aluminium fluoride complexes and free Al(3+) in soil samples. Aluminium speciation was studied in model solutions and soil extract samples by means of high performance ion chromatography (HPIC) with UV-VIS detection using post-column reaction with tiron for the separation and detection of aluminium fluoride complex and Al(3+) forms during one analysis. The paper presents particular stages of the chromatographic process optimization involving selecting the appropriate eluent strength, type of elution or concentration and quantity of derivatization reagent. HPIC was performed on a bifunctional analytical column Dionex IonPac CS5A. The use of gradient elution and the eluents A: 1M NH(4)Cl and B: water acidified to pH of eluent phase, enabled full separation of fluoride aluminium forms as AlF(2)(+), AlF(3)(0), AlF(4)(-) (first signal), AlF(2+) (second signal) and form Al(3+) in a single analytical procedure. The proposed new method HPIC-UVVIS was applied successfully in the quantitative and qualitative analysis of soil samples. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. Terahertz emission from collapsing field domains during switching of a gallium arsenide bipolar transistor.

    Science.gov (United States)

    Vainshtein, Sergey; Kostamovaara, Juha; Yuferev, Valentin; Knap, Wojciech; Fatimy, Abdel; Diakonova, Nina

    2007-10-26

    Broadband pulsed THz emission with peak power in the sub-mW range has been observed experimentally during avalanche switching in a gallium arsenide bipolar junction transistor at room temperature, while significantly higher total generated power is predicted in simulations. The emission is attributed to very fast oscillations in the conductivity current across the switching channels, which appear as a result of temporal evolution of the field domains generated in highly dense electron-hole plasma. This plasma is formed in turn by powerful impact ionization in multiple field domains of ultrahigh amplitude.

  14. Efficiency Enhancement of Gallium Arsenide Photovoltaics Using Solution-Processed Zinc Oxide Nanoparticle Light Scattering Layers

    Directory of Open Access Journals (Sweden)

    Yangsen Kang

    2015-01-01

    Full Text Available We demonstrate a high-throughput, solution-based process for subwavelength surface texturing of a III-V compound solar cell. A zinc oxide (ZnO nanoparticle ink is spray-coated directly on top of a gallium arsenide (GaAs solar cell. The nanostructured ZnO films have demonstrated antireflection and light scattering properties over the visible/near-infrared (NIR spectrum. The results show a broadband spectral enhancement of the solar cell external quantum efficiency (EQE, a 16% enhancement of short circuit current, and a 10% increase in photovoltaic efficiency.

  15. Efficiency Enhancement of Gallium Arsenide Photovoltaic Using Solution-Processed Zinc Oxide Nanoparticle Light Scattering Layers

    International Nuclear Information System (INIS)

    Kang, Y.; Huo, Y.; Chen, Y.; Christoforo, M. G.; Harris, J.S.; Liang, D.; Mehra, S.; Salleo, A.; Harris, J.S.; Harris, J.S.

    2015-01-01

    We demonstrate a high-throughput, solution-based process for sub wavelength surface texturing of a III-V compound solar cell. A zinc oxide (ZnO) nanoparticle ink is spray-coated directly on top of a gallium arsenide (GaAs) solar cell. The nano structured ZnO films have demonstrated antireflection and light scattering properties over the visible/near-infrared (NIR) spectrum. The results show a broadband spectral enhancement of the solar cell external quantum efficiency (EQE), a 16% enhancement of short circuit current, and a 10% increase in photovoltaic efficiency

  16. Comparative performance of silicon and gallium arsenide solar cells on a high altitude sounding rocket

    Science.gov (United States)

    Thomas, N. L.; Chisel, D. M.

    1977-01-01

    The use of sounding rockets for calibrating solar cells offers two principal advantages: (1) there is no effect due to the terrestrial atmosphere, and (2) the cells are recoverable immediately after the calibration. On March 30, 1976, 29 n/p silicon and four p/n gallium arsenide solar cells were calibrated in space and successfully recovered from a NASA-Astrobee F rocket that reached a peak altitude of 230 km. Approximately 75 IV characteristic curves were generated for 32 of the cells to an accuracy of plus or minus 0.2 ma and plus or minus 0.2 mV.

  17. On-orbit performance of LIPS gallium arsenide solar cell experiment

    Science.gov (United States)

    Bavaro, T.; Francis, R.; Pennell, M.

    1984-01-01

    Telemetry from the Living Plume Shield's gallium arsenide solar panel experiment was evaluated to determine degradation. The data were culled to preclude spurious results from possible shadowing or inaccurate measurements on a cold array. Two independent methods were then used to obtain the maximum power points and the various characteristics of the solar array. Fill factor, open circuit voltage, short circuit current, and series and shunt resistances were examined. The data analysis concluded that, to date, nearly all of the solar array degradation is due to the reduction in the short circuit current.

  18. Growth of Gold-assisted Gallium Arsenide Nanowires on Silicon Substrates via Molecular Beam Epitaxy

    Directory of Open Access Journals (Sweden)

    Ramon M. delos Santos

    2008-06-01

    Full Text Available Gallium arsenide nanowires were grown on silicon (100 substrates by what is called the vapor-liquid-solid (VLS growth mechanism using a molecular beam epitaxy (MBE system. Good quality nanowires with surface density of approximately 108 nanowires per square centimeter were produced by utilizing gold nanoparticles, with density of 1011 nanoparticles per square centimeter, as catalysts for nanowire growth. X-ray diffraction measurements, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy revealed that the nanowires are epitaxially grown on the silicon substrates, are oriented along the [111] direction and have cubic zincblende structure.

  19. High Pressure X-ray Diffraction Study on Icosahedral Boron Arsenide (B12As2)

    Energy Technology Data Exchange (ETDEWEB)

    J Wu; H Zhu; D Hou; C Ji; C Whiteley; J Edgar; Y Ma

    2011-12-31

    The high pressure properties of icosahedral boron arsenide (B12As2) were studied by in situ X-ray diffraction measurements at pressures up to 25.5 GPa at room temperature. B12As2 retains its rhombohedral structure; no phase transition was observed in the pressure range. The bulk modulus was determined to be 216 GPa with the pressure derivative 2.2. Anisotropy was observed in the compressibility of B12As2-c-axis was 16.2% more compressible than a-axis. The boron icosahedron plays a dominant role in the compressibility of boron-rich compounds.

  20. Ultra-low power fiber-coupled gallium arsenide photonic crystal cavity electro-optic modulator.

    Science.gov (United States)

    Shambat, Gary; Ellis, Bryan; Mayer, Marie A; Majumdar, Arka; Haller, Eugene E; Vučković, Jelena

    2011-04-11

    We demonstrate a gallium arsenide photonic crystal cavity injection-based electro-optic modulator coupled to a fiber taper waveguide. The fiber taper serves as a convenient and tunable waveguide for cavity coupling with minimal loss. Localized electrical injection of carriers into the cavity region via a laterally doped p-i-n diode combined with the small mode volume of the cavity enable ultra-low energy modulation at sub-fJ/bit levels. Speeds of up to 1 GHz are demonstrated with photoluminescence lifetime measurements revealing that the ultimate limit goes well into the tens of GHz. © 2011 Optical Society of America

  1. DNA detection using plasmonic enhanced near-infrared photoluminescence of gallium arsenide.

    Science.gov (United States)

    Tang, Longhua; Chun, Ik Su; Wang, Zidong; Li, Jinghong; Li, Xiuling; Lu, Yi

    2013-10-15

    Efficient near-infrared detection of specific DNA with single nucleotide polymorphism selectivity is important for diagnostics and biomedical research. Herein, we report the use of gallium arsenide (GaAs) as a sensing platform for probing DNA immobilization and targeting DNA hybridization, resulting in ∼8-fold enhanced GaAs photoluminescence (PL) at ∼875 nm. The new signal amplification strategy, further coupled with the plasmonic effect of Au nanoparticles, is capable of detecting DNA molecules with a detection limit of 0.8 pM and selectivity against single base mismatches. Such an ultrasensitive near-infrared sensor can find a wide range of biochemical and biomedical applications.

  2. Analytical and experimental procedures for determining propagation characteristics of millimeter-wave gallium arsenide microstrip lines

    Science.gov (United States)

    Romanofsky, Robert R.

    1989-01-01

    In this report, a thorough analytical procedure is developed for evaluating the frequency-dependent loss characteristics and effective permittivity of microstrip lines. The technique is based on the measured reflection coefficient of microstrip resonator pairs. Experimental data, including quality factor Q, effective relative permittivity, and fringing for 50-omega lines on gallium arsenide (GaAs) from 26.5 to 40.0 GHz are presented. The effects of an imperfect open circuit, coupling losses, and loading of the resonant frequency are considered. A cosine-tapered ridge-guide text fixture is described. It was found to be well suited to the device characterization.

  3. Development of gallium arsenide high-speed, low-power serial parallel interface modules: Executive summary

    Science.gov (United States)

    1988-01-01

    Final report to NASA LeRC on the development of gallium arsenide (GaAS) high-speed, low power serial/parallel interface modules. The report discusses the development and test of a family of 16, 32 and 64 bit parallel to serial and serial to parallel integrated circuits using a self aligned gate MESFET technology developed at the Honeywell Sensors and Signal Processing Laboratory. Lab testing demonstrated 1.3 GHz clock rates at a power of 300 mW. This work was accomplished under contract number NAS3-24676.

  4. Gallium arsenide particle detectors: a study of the active region and charge-collection efficiency

    International Nuclear Information System (INIS)

    Berluti, L.; D'Auria, S.; Mattei, G.; Proia, M.; Rinaldi, P.; Zichichi, A.

    1995-01-01

    Gallium arsenide particle detectors made by Alenia SpA have been tested within the context of the RD-8 project and found to have a high charge-collection efficiency (75%). We have analysed the data and found the overall behaviour of these detectors to be coherent and understandable in terms of one function: the local charge-collection efficiency. Two ways have been used to measure the width of the active region and the increase of such a width as a function of bias is found not to be consistent with a simple square-root law. ((orig.))

  5. Aluminium and Alzheimer's disease: the science that describes the link

    National Research Council Canada - National Science Library

    Exley, Christopher

    2001-01-01

    ... that has been encircled is the gene for the amyloid precursor protein. (Thanks to Walter Lukiw for supplying this information.) Aluminium and Alzheimer's Disease: The Science that Describes the LinkAluminium and Alzheimer's Disease The Science that Describes the Link Edited by Christopher Exley Birchall Centre for Inorganic Chemistry and Materials Scienc...

  6. Enhanced corrosion protection by microstructural control of aluminium brazing sheet

    NARCIS (Netherlands)

    Norouzi Afshar, F.

    2013-01-01

    Aluminium brazing sheet is a sandwich material made out of two aluminium alloys (AA4xxx/AA3xxx) and is widely used in automotive heat exchangers. One of the main performance criteria for heat exchanger units is the lifetime of the product. The lifetime of the heat exchanger units is determined by

  7. An interesting and efficient green corrosion inhibitor for aluminium ...

    African Journals Online (AJOL)

    An interesting and efficient green corrosion inhibitor for aluminium from extracts of Moringa oleifera in acidic solution. ... L.A. Nnanna, I.O. Owate ... using gravimetric and thermometric techniques at 30 and 60oC. Results obtained showed that Moringa oleifera functioned as an excellent corrosion inhibitor for aluminium in the ...

  8. Effects and mechanisms of grain refinement in aluminium alloys

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Grain refinement plays a crucial role in improving characteristics and properties of cast and wrought aluminium alloys. Generally Al–Ti and Al–Ti–B master alloys are added to the aluminium alloys to grain refine the solidified product. The mechanism of grain refinement is of considerable controversy in the scientific ...

  9. Three body abrasion of laser surface alloyed aluminium AA1200

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2012-06-01

    Full Text Available Laser surface alloying of aluminium AA1200 was performed with a 4 kW Nd:YAG laser to improve the abrasion wear resistance. Aluminium surfaces reinforced with metal matrix composites and intermetallic phases were achieved. The phases present depended...

  10. Comparative study of highly dense aluminium- and gallium-doped ...

    Indian Academy of Sciences (India)

    Administrator

    cause of their optoelectronic properties in addition to low cost, high stability and excellent surface uniformity (low roughness). Doping zinc oxide with some elements like aluminium, gallium, boron, niobium and indium has a great impact for having enhancements of its optical and electrical properties. Aluminium and gallium ...

  11. Laser cladding of aluminium using TiB2

    CSIR Research Space (South Africa)

    Kumar, S

    2010-03-01

    Full Text Available Modification of Aluminium surface by injecting, dispersing and melting TiB2 powder with the help of a laser beam promises to enhance tribological properties of Aluminium. The present work consists of making single lines and various overlapping lines...

  12. The effects of aluminium and selenium supplementation on brain ...

    African Journals Online (AJOL)

    This in vivo study was designed to investigate the potential of aluminium (Al), in the absence of added iron, to participate in either antioxidant or pro-oxidant events. Some markers of oxidative stress were determined in liver and brain of rats exposed to aluminium lactate, either alone or in the presence of dietary supplements ...

  13. Effects and mechanisms of grain refinement in aluminium alloys

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Grain refinement plays a crucial role in improving characteristics and properties of cast and wrought aluminium alloys. Generally Al–Ti and Al–Ti–B master alloys are added to the aluminium alloys to grain refine the solidified product. The mechanism of grain refinement is of considerable controversy in the ...

  14. Carbonaceous alumina films deposited by MOCVD from aluminium ...

    Indian Academy of Sciences (India)

    Spectroscopic ellipsometry was used to characterize carbonaceous, crystalline aluminium oxide films grown on Si(100) by low-pressure metal organic chemical vapour deposition, using aluminium acetylacetonate as the precursor. The presence of carbon in the films, attribured to the use of a metalorganic precursor for the ...

  15. Aluminium removal from water after defluoridation with the electrocoagulation process.

    Science.gov (United States)

    Sinha, Richa; Mathur, Sanjay; Brighu, Urmila

    2015-01-01

    Fluoride is the most electronegative element and has a strong affinity for aluminium. Owing to this fact, most of the techniques used for fluoride removal utilized aluminium compounds, which results in high concentrations of aluminium in treated water. In the present paper, a new approach is presented to meet the WHO guideline for residual aluminium concentration as 0.2 mg/L. In the present work, the electrocoagulation (EC) process was used for fluoride removal. It was found that aluminium content in water increases with an increase in the energy input. Therefore, experiments were optimized for a minimum energy input to achieve the target value (0.7 mg/L) of fluoride in resultant water. These optimized sets were used for further investigations of aluminium control. The experimental investigations revealed that use of bentonite clay as coagulant in clariflocculation brings down the aluminium concentration of water below the WHO guideline. Bentonite dose of 2 g/L was found to be the best for efficient removal of aluminium.

  16. Combined Corrosion and Wear of Aluminium Alloy 7075-T6

    NARCIS (Netherlands)

    Liu, Y.; Mol, J.M.C.; Janssen, G.C.A.M.

    2016-01-01

    The aluminium alloy 7075-T6 is widely used in engineering. In some applications, like slurry transport, corrosion and abrasion occur simultaneously, resulting in early material failure. In the present work, we investigated the combined effect of corrosion and wear on the aluminium alloy 7075-T6. We

  17. Aluminium Tolerance of Four Bean ( Phaseolus vulgaris L.) Varieties ...

    African Journals Online (AJOL)

    Root elongation produced superior differential rating in assessing for aluminium toxicity in the beans. On the other hand, Eriochrome cyanine R staining lacked clear differentiation especially where there were marginal differences of Al tolerance. It follows that, screening for aluminium tolerance in common beans can ...

  18. Aluminium Electroplating on Steel from a Fused Bromide Electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Prabhat Tripathy; Laura Wurth; Eric Dufek; Toni Y. Gutknecht; Natalie Gese; Paula Hahn; Steven Frank; Guy Fredrickson; J Stephen Herring

    2014-08-01

    A quaternary bromide bath (LiBr-KBr-CsBr-AlBr3) was used to electro-coat aluminium on steel substrates. The electrolyte was prepared by the addition of AlBr3 into the eutectic LiBr-KBr-CsBr melt. A smooth, thick, adherent and shiny aluminium coating could be obtained with 80 wt.% AlBr3 in the ternary melt. The SEM photographs of the coated surfaces suggest the formation of thick and dense coatings with good aluminium coverage. Both salt immersion and open circuit potential measurement suggest that the coatings did display good corrosion-resistance behavior. Annealing of the coated surfaces, prior to corrosion tests, suggested the robustness of the metallic aluminium coating in preventing the corrosion of the steel surfaces. Studies also indicated that the quaternary bromide plating bath can potentially provide a better aluminium coating on both ferrous and non-ferrous metals, including complex surfaces/geometries.

  19. Aluminium/iron reinforced polyfurfuryl alcohol resin as advanced biocomposites

    Directory of Open Access Journals (Sweden)

    Rakesh Kumar

    2016-07-01

    Full Text Available Aluminium and iron are widely used in construction sectors for the preparation of advanced composites with epoxy resins as matrices. In recent times, there are several reports on the polymerization of polyfufuryl alcohol (PFA a thermoset bioresins from furfuryl alcohol (FA. FA is obtained from waste of sugarcane bagasse. In this work, first the possibility of curing PFA from FA in the presence of aluminium or iron has been explored. Absorbance results from colorimeter/spectrophotometerindicated that the curing of FA to PFA in presence of aluminium started easily while in presence of iron the curing of FA to PFA could not start. Based on the above results, aluminium wire reinforced composites were successfully prepared with three different weight fractions (0.13, 0.09 and 0.07 of aluminium wire. The mechanical properties of these composites were determined theoretically and reported.

  20. Calculation of electron transmission through aluminium foil

    International Nuclear Information System (INIS)

    Abroyan, M.A.; Mel'ker, A.I.; Mikhajlin, A.I.; Sirotinkin, V.V.; Tokmakov, I.L.

    1987-01-01

    Calculated by Monte Carlo method energy and angular distributions of electrons transmitted through aluminium foil with 50 μm thickness are presented. 200-500 electron energy ranges and angles of electron incidence on foil from 0 to 40 deg C are considered. That allows to use results for more universal accelerator group, for example, for accelerators with scanning beam used in industry. The received values of angular and energy characteristics allow to increase essentially estimation accuracy of accelerator extraction devices and dose distribution on irradiating item

  1. Deviatoric response of the aluminium alloy, 5083

    Science.gov (United States)

    Appleby-Thomas, Gareth; Hazell, Paul; Millett, Jeremy; Bourne, Neil

    2009-06-01

    Aluminium alloys such as 5083 are established light weight armour materials. As such, the shock response of these materials is of great importance. The shear strength of a material under shock loading provides an insight into its ballistic performance. In this investigation embedded manganin stress gauges have been employed to measure both the longitudinal and lateral components of stress during plate impact experiments over a range of impact stresses. In turn, these results were used to determine the shear strength and to investigate the time dependence of lateral stress behind the shock front to give an indication of material response.

  2. Convenient synthesis of deuterated aluminium hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Pawelke, Roland H.; Felderhoff, Michael; Weidenthaler, Claudia [Max-Planck-Institut fuer Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Muelheim an der Ruhr (Germany); Schueth, Ferdi [Max-Planck-Institut fuer Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Muelheim an der Ruhr (Germany)], E-mail: schueth@mpi-muelheim.mpg.de

    2008-09-15

    We describe the ball-milling synthesis of alkali metal deuterides from commercial lithium aluminium deuteride. This reaction principle was exemplified by the mechanochemical synthesis of NaAlD{sub 4} and KAlD{sub 4}. NaAlD{sub 4} was prepared on the multi-gram scale by this procedure and purified by standard wet-chemical separation. Pure NaAlD{sub 4} was obtained and used for the synthesis of Ca(AlD{sub 4}){sub 2}. The formation of all products was verified by X-ray diffraction.

  3. Experimental fatigue curves for aluminium brazed areas

    Science.gov (United States)

    Dimitescu, A.; Babiş, C.; Niţoi, D. F.; Radu, C.

    2017-08-01

    An important factor for the quality of joints is the brazed area. The fatigue check occupies a major position among many test procedures and methods, especially by the joining technologies. The results of processing the fatigue data experiments for aluminium brazed samples are used to find the regression function and the response surface methodology. The fatigue process of mechanical components under service loading is stochastic in nature. The prediction of time-dependent fatigue reliability is critical for the design and maintenance planning of many structural components.

  4. Friction stir welding of single crystal aluminium

    DEFF Research Database (Denmark)

    Fonda, Richard Warren; Wert, John A.; Reynolds, A.P.

    2007-01-01

    Friction stir welds were prepared in different orientations in an aluminium single crystal. The welds were quenched to preserve the microstructure surrounding the tool and then electron backscattered diffraction was used to reveal the generation of grain boundaries and the evolution...... to new crystal orientations, producing new grain boundaries in the process. These refined grains develop a {112}. texture closer to the tool. Large conventionally recrystallised grains sometimes form in the outer regions of the refined grain structure, but become ever more deformed as they approach...

  5. Aluminium and the automobile. Aluminium und Automobil. Vortraege eines internationalen Symposiums der Aluminium-Zentrale, Duesseldorf, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1981-04-01

    The first symposium on 'Aluminium and the Automobile' took place in March 1976. The lectures of the latest symposium report on the time in between; with special regard to the extent and intensity with wich aluminium - whose advantages and desadvantages are known - was a subject of research and development work done by car producers and parts- and accessory producing industry. Producers of engine blocks, wheels brakes, sunroofs, window-glass mechanisms, heat exchangers, air-filters, drive shafts - just to mention a few described their success but also gave and account of so far unsolved problems. Aluminum and car producers from abroad gave valuable contributions as well. Good news is the technical progress which was clearly reflected in all the lectures. The automobile of the future needs to be further developed in order te fulfill the requirements of lower weight and energy saving cost reduction is equally important for the German and European car industry due to the increasingly hard competitive struggle. Contrary to previous predictions a sufficient supply of alluminium with be available in the years to come.

  6. Gas accumulation at grain boundaries during 800 MeV proton irradiation of aluminium and aluminium-alloys

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Horsewell, Andy; Sommer, W. F.

    1986-01-01

    ) showed a complete absence of voids or bubbles in the grain interiors of the aluminium and the aluminium-alloys. Bubbles were clearly visible by TEM at grain boundaries in pure Al and the AlMg3 alloy; but bubbles were not visible in the Al6061 alloy. The bubble density in the AlMg3 alloy was considerably...

  7. Inflammatory process decrease by gallium-aluminium-arsenide (GaAlAs) low intensity laser irradiation on postoperative extraction of impacted lower third molar

    International Nuclear Information System (INIS)

    Atihe, Mauricio Martins

    2002-01-01

    This study aimed the observation of inflammatory process decrease by the use of GaAlAs Low Intensity Laser (λ=830 nm; 40 mW) irradiation. Five patients were selected and submitted to surgery of impacted lower third molars, both right and left sides at different occasions. On a first stage, a tooth of a random chosen side - right or left - was extracted by conventional surgery, without LILT. The inflammatory process was measured at postoperative on the first, third and seventh days. This side was then called 'control side'. After 21 days, period in which the inflammatory process of the first surgery was terminated, the other side surgery took place, this time using LILT (4 J at four spots) at postoperative, first and third days. As the previous surgery, the inflammatory process was also measured at postoperative on the first, third and seventh days. This side was called 'experimental or lased side'. The inflammatory process was evaluated by measuring its four characteristic signs: swelling, pain, color and temperature. It was clearly observed a decrease for swelling, pain and color on the lased side which presented significant inference and descriptive statistics. It can be concluded that GaAlAs Low Intensity Laser (λ=830 nm) can surely be used as an additional and important anti-inflammatory source on impacted lower third molar surgeries. (author)

  8. Optimal power settings of aluminum gallium arsenide lasers in caries inhibition - An in vitro study.

    Science.gov (United States)

    Sharma, Sonali; Hegde, Mithra N; Sadananda, Vandana; Mathews, Blessen

    2016-01-01

    Incipient carious lesions are characterized by subsurface dissolution due to more fluoride ions in the 50-100 microns of the tooth's outer surface. To determine an optimal power setting for 810 nm aluminum gallium arsenide laser for caries inhibition. Fifty-four caries-free extracted teeth were sectioned mesiodistally. The samples were divided into 18 groups for each power setting being evaluated. Each group had six samples. The laser used is 810 nm aluminum gallium arsenide laser with power setting from 0.1 watts to 5 watts. Laser fluorescence based device was used to evaluate the effect of irradiation. Paired "t" test, one-way analysis of variance (ANOVA), Tukey's post hoc test, and the Pearson's correlation test. The paired t-test showed that there is minimum divergence from the control for 3.5 watts. Tukey's post hoc test also showed statistically significantly results for 3.5 watts. The Pearson's correlation test showed that there was negative correlation between the watts and irradiation. The power setting that gave statistically significant results was 3.5 watts.

  9. Optimal power settings of aluminum gallium arsenide lasers in caries inhibition — An in vitro study

    Science.gov (United States)

    Sharma, Sonali; Hegde, Mithra N; Sadananda, Vandana; Mathews, Blessen

    2016-01-01

    Context: Incipient carious lesions are characterized by subsurface dissolution due to more fluoride ions in the 50-100 microns of the tooth's outer surface. Aims: To determine an optimal power setting for 810 nm aluminum gallium arsenide laser for caries inhibition. Materials and Methods: Fifty-four caries-free extracted teeth were sectioned mesiodistally. The samples were divided into 18 groups for each power setting being evaluated. Each group had six samples. The laser used is 810 nm aluminum gallium arsenide laser with power setting from 0.1 watts to 5 watts. Laser fluorescence based device was used to evaluate the effect of irradiation. Statistical Analysis Used: Paired “t” test, one-way analysis of variance (ANOVA), Tukey's post hoc test, and the Pearson's correlation test. Results: The paired t-test showed that there is minimum divergence from the control for 3.5 watts. Tukey's post hoc test also showed statistically significantly results for 3.5 watts. The Pearson's correlation test showed that there was negative correlation between the watts and irradiation. Conclusions: The power setting that gave statistically significant results was 3.5 watts. PMID:27099427

  10. MBE growth of nitride-arsenide materials for long wavelength optoelectronics[Molecular Beam Epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Spruytte, S.G.; Coldren, C.W.; Marshall, A.F.; Larson, M.C.; Harris, J.S.

    2000-07-01

    Group III-Nitride-Arsenides are promising materials for 1.3{micro}m and 1.55{micro}m telecommunications optoelectronic devices grown on GaAs substrates. Nitride-Arsenide materials were grown by molecular beam epitaxy (MBE) using a radio frequency (rf) nitrogen plasma. The plasma conditions that maximize the amount of atomic nitrogen versus molecular nitrogen were determined using the emission spectrum of the plasma. Under constant plasma source conditions and varying group III flux, the nitrogen concentration in the film is inversely proportional to the group III flux (i.e., the nitrogen sticking coefficient is unity). The relationship between nitrogen concentration in the film and lattice parameter of the film is not linear for nitrogen concentrations above 2.9 mole % GaN, indicating that some nitrogen is incorporated on other locations than the group V lattice sites. For films with these higher nitrogen concentrations, XPS indicates that the nitrogen exists in two configurations: a Gallium-Nitrogen bond and another type of nitrogen complex in which nitrogen is less strongly bonded to Gallium atoms. Annealing removes this nitrogen complex and allows some of the nitrogen to diffuse out of the film. Annealing also improves the crystal quality of GaAsN quantum wells.

  11. THE QUANTUM-WELL STRUCTURES OF SELF ELECTROOPTIC-EFFECT DEVICES AND GALLIUM-ARSENIDE

    Directory of Open Access Journals (Sweden)

    Mustafa TEMİZ

    1996-02-01

    Full Text Available Multiple quantum-well (MQW electroabsorptive self electro optic-effect devices (SEEDs are being extensively studied for use in optical switching and computing. The self electro-optic-effect devices which has quantum-well structures is a new optoelectronic technology with capability to obtain both optical inputs and outputs for Gallium-Arsenide/Aluminum Gallium-Arsenide (GaAs/AlGaAs electronic circuits. The optical inputs and outputs are based on quantum-well absorptive properties. These quantum-well structures consist of many thin layers of semiconductors materials of GaAs/AlGaAs which have emerged some important directions recently. The most important advance in the physics of these materials since the early days has been invention of the heterojunction structures which is based at present on GaAs technology. GaAs/AlGaAs structures present some important advantages to relevant band gap and index of refraction which allow to form the quantum-well structures and also to make semiconductor lasers, dedectors and waveguide optical switches.

  12. Reactions on carbon anodes in aluminium electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Eidet, Trygve

    1997-12-31

    The consumption of carbon anodes and energy in aluminium electrolysis is higher than what is required theoretically. This thesis studies the most important of the reactions that consume anode materials. These reactions are the electrochemical anode reaction and the airburn and carboxy reactions. The first part of the thesis deals with the kinetics and mechanism of the electrochemical anode reaction using electrochemical impedance spectroscopy. The second part deals with air and carboxy reactivity of carbon anodes and studies the effects of inorganic impurities on the reactivity of carbon anodes in the aluminium industry. Special attention is given to sulphur since its effect on the carbon gasification is not well understood. Sulphur is always present in anodes, and it is expected that the sulphur content of available anode cokes will increase in the future. It has also been suggested that sulphur poisons catalyzing impurities in the anodes. Other impurities that were investigated are iron, nickel and vanadium, which are common impurities in anodes which have been reported to catalyze carbon gasification. 88 refs., 92 figs., 24 tabs.

  13. Construction and test of a detector plane with gallium arsenide sensor; Aufbau und Test einer Detektorebene mit Galliumarsenidsensor

    Energy Technology Data Exchange (ETDEWEB)

    Kollowa, Sandro

    2012-05-15

    Aim of this thesis was the construction and test of a detector plane with gallium arsenide as sensor for the BeamCal. The front-end-ASICSs (ASIC=Application Specific Integrated Circuit) are first prototype for the readout electronics both for BeamCal and for LumiCal.

  14. Structural and electrooptical characteristics of quantum dots emitting at 1.3 μm on gallium arsenide

    DEFF Research Database (Denmark)

    Fiore, A.; Oesterle, U.; Stanley, R.P.

    2001-01-01

    We present a comprehensive study of the structural and emission properties of self-assembled InAs quantum dots emitting at 1.3 mum. The dots are grown by molecular beam epitaxy on gallium arsenide substrates. Room-temperature emission at 1.3 mum is obtained by embedding the dots in an InGaAs layer...

  15. A novel three-jet microreactor for localized metal-organic chemical vapour deposition of gallium arsenide : Design and simulation

    NARCIS (Netherlands)

    Konakov, S.A.; Krzhizhanovskaya, V.V.

    2016-01-01

    We present a novel three-jet microreactor design for localized deposition of gallium arsenide (GaAs) by low-pressure Metal-Organic Chemical Vapour Deposition (MOCVD) for semiconductor devices, microelectronics and solar cells. Our approach is advantageous compared to the standard lithography and

  16. Dietary exposure to aluminium of the Hong Kong population.

    Science.gov (United States)

    Wong, Waiky W K; Chung, Stephen W C; Kwong, K P; Yin Ho, Yuk; Xiao, Ying

    2010-04-01

    A total of 256 individual food samples were collected in Hong Kong for aluminium testing. Most of food samples were analysed in ready-to-eat form. High aluminium levels were found in steamed bread/bun/cake (mean: 100-320 mg kg(-1)), some bakery products such as muffin, pancake/waffle, coconut tart and cake (mean: 250, 160, 120 and 91 mg kg(-1), respectively), and jellyfish (ready-to-eat form) (mean: 1200 mg kg(-1)). The results demonstrated that aluminium-containing food additives have been widely used in these food products. The average dietary exposure to aluminium for a 60 kg adult was estimated to be 0.60 mg kg(-1) bw week(-1), which amounted to 60% of the new PTWI established by JECFA. The main dietary source was "steamed bread/bun/cake", which contributed to 60% of the total exposure, followed by "bakery products" and "jellyfish", which contributed to 23 and 10% of the total exposure, respectively. However, the estimation did not include the intake of aluminium from natural food sources, food contact materials or other sources (e.g. drinking water). Although the results indicated that aluminium it is unlikely to cause adverse health effect for the general population, the risk to some populations who regularly consume foods with aluminium-containing food additives cannot be ruled out.

  17. New developments in aluminium titanate ceramics and refractories

    Energy Technology Data Exchange (ETDEWEB)

    Alecu, I.D.; Cilia, R.A.; Dean, G.A.; Reuben, R.; Stead, R.J.; Wing, R.F. [Rojan Advanced Ceramics Pty Ltd., Spearwood, WA (Australia)

    2002-07-01

    During the recent years there has been a world-wide resurgence in the interest for aluminium titanate ceramics. Aluminium titanate (AT) possesses a unique collection of outstanding properties that make it a favourite candidate for applications where thermal shock resistance, thermal and / or phonic insulation, or compatibility with molten metals are key requirements. Particularly promising are the applications of aluminium titanate in the non-ferrous metallurgical industry, primarily in aluminium smelters and foundries. Aluminium titanate is best suitable for manufacturing ceramic components for gravity and low-pressure die casting of non-ferrous metals and alloys. Examples of such components are casting nozzles and spouts, sprue bushes, connecting tubes, riser tubes, etc. As aluminium titanate (AT) is generally known as a ceramic material with a modest mechanical strength, most applications have been so far as components that either are small enough, or are subjected to small enough mechanical loads, so that the risk of failure is acceptably low. Currently there is an increasing demand for larger and / or stronger components, which obviously require significantly stronger aluminium titanate ceramic materials, as well as adequate forming technologies. (orig.)

  18. Does allergen-specific immunotherapy induce contact allergy to aluminium?

    Science.gov (United States)

    Netterlid, Eva; Hindsén, Monica; Siemund, Ingrid; Björk, Jonas; Werner, Sonja; Jacobsson, Helene; Güner, Nuray; Bruze, Magnus

    2013-01-01

    Persistent, itching nodules have been reported to appear at the injection site after allergen-specific immuno-therapy with aluminium-precipitated antigen extract, occasionally in conjunction with contact allergy to aluminium. This study aimed to quantify the development of contact allergy to aluminium during allergen-specific immunotherapy. A randomized, controlled, single-blind multicentre study of children and adults entering allergen-specific immunotherapy was performed using questionnaires and patch-testing. A total of 205 individuals completed the study. In the 3 study groups all subjects tested negative to aluminium before allergen-specific immunotherapy and 4 tested positive after therapy. In the control group 4 participants tested positive to aluminium. Six out of 8 who tested positive also had atopic dermatitis. Positive test results were found in 5/78 children and 3/127 adults. Allergen-specific immunotherapy was not shown to be a risk factor for contact allergy to aluminium. Among those who did develop aluminium allergy, children and those with atopic dermatitis were more highly represented.

  19. The varied functions of aluminium-activated malate transporters-much more than aluminium resistance.

    Science.gov (United States)

    Palmer, Antony J; Baker, Alison; Muench, Stephen P

    2016-06-15

    The ALMT (aluminium-activated malate transporter) family comprises a functionally diverse but structurally similar group of ion channels. They are found ubiquitously in plant species, expressed throughout different tissues, and located in either the plasma membrane or tonoplast. The first family member identified was TaALMT1, discovered in wheat root tips, which was found to be involved in aluminium resistance by means of malate exudation into the soil. However, since this discovery other family members have been shown to have many other functions such as roles in stomatal opening, general anionic homoeostasis, and in economically valuable traits such as fruit flavour. Recent evidence has also shown that ALMT proteins can act as key molecular actors in GABA (γ-aminobutyric acid) signalling, the first evidence that GABA can act as a signal transducer in plants. © 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  20. Corrosion issues of powder coated AA6060 aluminium profiles

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Valgarðsson, Smári; Jellesen, Morten Stendahl

    2015-01-01

    In this study detailed microstructural investigation of the reason for unexpected corrosion of powder coated aluminium alloy AA6060 windows profiles has been performed. The results from this study reveals that the failure of the window profiles was originated from the surface defects present...... on the extruded AA6060 aluminium profile after metallurgical process prior to powder coating. Surface defects are produced due to intermetallic particles in the alloy, which disturb the flow during the extrusion process. The corrosion mechanism leading to the failure of the powder coated AA6060 aluminium profiles...

  1. Recurrent sterile abscesses following aluminium adjuvant-containing vaccines.

    Science.gov (United States)

    Klein, Nicola P; Edwards, Kathryn M; Sparks, Robert C; Dekker, Cornelia L

    2009-01-01

    Abscess formation following immunisation is a previously reported complication, generally associated with microbial contamination of the vaccine. Less commonly, such abscesses have been sterile. Here we describe two children evaluated in the Center for Disease Control and Prevention (CDC)-funded Clinical Immunization Safety Assessment (CISA) network who developed recurrent sterile abscesses after administration of vaccines containing aluminium adjuvant, either individually or in combination. Although the abscesses healed without sequelae, these occurrences support an association between receipt of aluminium adjuvant and sterile abscesses in susceptible patients. For patients with similar symptoms, clinicians may wish to choose a vaccine formulation containing the least amount of aluminium adjuvant.

  2. Aluminium determination in U Alx using atomic absorption spectrophotometry

    International Nuclear Information System (INIS)

    Dantas, E.S.K.; Pires, M.A.F.

    1994-01-01

    Available as short communication only. A method for aluminium determination in uranium-aluminium dispersions (U al x ) using atomic absorption spectrometry is presented. The sample is dissolved in nitric acid, heated, dried, and market up the volume with 0.1 N H NO 3 . The uranium is precipitated with 30% NaOH and the aluminium is determined in the solution after filtration. The determination limit achieved was 5 μg Al/mL. The method is reproducible. (author). 7 refs, 2 tabs

  3. Effect of pressurized steam on AA1050 aluminium

    DEFF Research Database (Denmark)

    Jariyaboon, Manthana; Møller, Per; Ambat, Rajan

    2012-01-01

    Purpose - The purpose of this paper is to understand the effect of pressurized steam on surface changes, structures of intermetallic particles and corrosion behavior of AA1050 aluminium. Design/methodology/approach - Industrially pure aluminium (AA1050, 99.5 per cent) surfaces were exposed...... reactivities was observed due to the formation of the compact oxide layer. Originality/value - This paper reveals a detailed investigation of how pressurized steam can affect the corrosion behaviour of AA1050 aluminium and the structure of Fe-containing intermetallic particles....

  4. Characterization of solar cells for space applications. Volume 13: Electrical characteristics of Hughes LPE gallium arsenide solar cells as a function of intensity and temperature

    Science.gov (United States)

    Anspaugh, B. E.; Beckert, D. M.; Downing, R. G.; Miyahira, T. F.; Weiss, R. S.

    1980-01-01

    Electrical characteristics of Hughes Liquid phase epitaxy, P/N gallium aluminum arsenide solar cells are presented in graphical and tabular format as a function of solar illumination intensity and temperature.

  5. Orbital friction stir welding of aluminium pipes

    International Nuclear Information System (INIS)

    Engelhard, G.; Hillers, T.

    2002-01-01

    Friction stir welding (FSW) was originally developed for flat plates. This contribution shows how it can be applied to the welding of aluminium pipes. Pipes made of AlMG 3 (EN5754), AlMg 4.5Mn (EN5083) and AlMgSi 0.5 (EN6106) with dimensions of Da 600 and 520 x 10-8 mm were welded. The FSW orbital system comprises an annular cage with integrated FSW head, a hydraulic system, and a control unit. The welds were tested successfully according to EN 288. The mechanical and technical properties of the welds were somewhat better than with the TIG orbital process, and welding times were about 40 percent shorter [de

  6. Brazing of Titanium with Aluminium Alloys

    Directory of Open Access Journals (Sweden)

    Winiowski A.

    2017-06-01

    Full Text Available This study presents results of vacuum diffusion brazing of Grade 2 titanium with 6082 (AlMg1Si0.6Cu0.3 aluminium alloy using B-Ag72Cu-780 (Ag72Cu28 grade silver brazing metal as an interlayer. Brazed joints underwent shear tests, light-microscopy-based metallographic examinations and structural examinations using scanning electron microscopy (SEM and X-ray energy dispersive spectrometry (EDS. The highest quality and shear strength of 20 MPa was characteristic of joints brazed at 530°C with a 30-minute hold. The structural examinations revealed that in diffusion zone near the boundary with titanium the braze contained solid solutions based on hard and brittle Ti-Al type intermetallic phases determining the strength of the joints.

  7. Experimental analysis of cut welding in aluminium

    DEFF Research Database (Denmark)

    Dorph, Pernille; De Chiffre, Leonardo; Bay, Niels

    1993-01-01

    Cut welding is a newly developed cold pressure welding process. In the present work, an experimental investigation was carried out analyzing the mechanisms involved in cut welding of a block to a strip. Experiments were carried out in technically pure aluminium. The investigation has involved...... tensile testing and metallographic investigations of the welds. The results show that this variant of cut welding is a very reproducible process giving a weld strength equal to 30-40% the strength of the parent material. The experiments have shown that the reason for this relatively low strength...... is an uneven pressure distribution along the weld due to a wave formed during sliding. Attempts to alter the material flow during sliding are presented....

  8. Study of hydrogen implanted in aluminium

    International Nuclear Information System (INIS)

    Bugeat, J.P.; Chami, A.C.; Danielou, R.; Ligeon, E.

    1976-01-01

    An aluminium sample was implanted with deuterium and hydrogen at 5keV and 10keV respectively. The 1 H( 11 B,α) 8 Be* and D( 3 He,p) 4 He reactions were used for the analysis of H and D respectively. The implanted deuterium was shown to be as a whole in a tetrahedral site as far as the implantation temperature is lower than 175K, beyond that temperature the deuterium is randomly located. When the implantation temperature increases from 33K up to 275K the tetrahedral siting remains during annealing. The migration temperatures of hydrogen (or temperature of transition from the tetrahedral siting to a random distribution) experimentally observed during annealing (300K) and for increased implantation temperatures, show that the tetrahedral site is associated with a monovacancy migrating at 300K, the diffusion temperature of hydrogen being lower than 180K [fr

  9. Silane based coating of aluminium mold

    DEFF Research Database (Denmark)

    2013-01-01

    A method of preparing an aluminum mold for injection molding is provided, the method comprises the steps of providing an aluminum mold having a least one surface, subjecting the at least one surface to a gas or liquid phase silane to thereby form an anti-stiction coating, the anti-stiction coating...... comprising a chemically bonded monolayer of silane compounds on the at least one surface wherein the silane is a halogenated silane. The at least one surface coated with the anti-stiction coating may be configured to withstand an injection molding process at a pressure above 100 MPa. Furthermore, a mold...... having at least one closed cavity is provided, at least one surface of the at least one cavity being an aluminium surface coated with a silane based coating layer. The silane based anti-stiction coating improves the anti-stiction properties of the mold which may allow for molding and demolding...

  10. Water state in basic aluminium tungstates

    International Nuclear Information System (INIS)

    Pozharskaya, L.A.; Pitsyuga, V.G.; Mokhosoev, M.V.

    1978-01-01

    Water state in basic aluminium tungstates is investigated using the method of proton magnetic resonance. Existence of various types of water molecules, differing by their geometry and bond energies, is established in the investigated compounds. The obtained results permit to suppose that in Al 6 (OH) 16 WO 4 x10H 2 O, AL 4 (OH) 10 WO 4 x5,5H 2 O and Al 3 (OH) 7 WO 7 x7H 2 O compounds coordinationally non-saturated oxygen atoms in anion are saturated basically at the expense of OH-groups, and water molecules form hydrogen bonds as opposed to Al 2 (OH) 4 WO 4 x7H 2 O and AlOH(WO 4 )x8.5H 2 O in which a considerable part of water molecules is bound directly with anion oxygen atoms

  11. Cost Trade Between Multi-Junction, Gallium Arsenide, and Silicon Solar Cells

    Science.gov (United States)

    Gaddy, Edward M.

    1995-01-01

    Multi-junction (MJ), gallium arsenide (GaAs), and silicon (Si) solar cells have respective test efficiencies of approximately 24%, 18.5% and 14.8%. Multi-junction and gallium arsenide solar cells weigh more than silicon solar 2 cells and cost approximately five times as much per unit power at the cell level. A trade is performed for the TRMM spacecraft to determine which of these cell types would have offered an overall performance and price advantage to the spacecraft. A trade is also performed for the multi-junction cells under the assumption that they will cost over ten times that of silicon cells at the cell level. The trade shows that the TRMM project, less the cost of the instrument, ground systems and mission operations, would spend approximately $552,000 dollars per kilogram to launch and suppon3science in the case of the spacecraft equipped with silicon solar cells. If these cells are changed out for gallium arsenide solar cells, an additional 31 kilograms of science can be launched and serviced at a price of approximately $90 thousand per kilogram. The weight reduction is shown to derive from the smaller area of the array and hence reductions in the weight of the array substrate and supporting structure. ff the silicon solar cells are changed out for multi-junction solar cells, an additional 45 kilograms of science above the silicon base line can be launched and supported at a price of approximately $58,000 per kilogram. The trade shows that even if the multi-junction cells are priced over ten times that of silicon cells, a price that is much higher than projected, that the additional 45 kilograms of science are launched and serviced at $180,000 per kilogram. This is still much less than the original $552,000 per kilogram to launch and service the science. Data and qualitative factors are presented to show that these figures are subject to a great deal of uncertainty. Nonetheless, the benefit of the higher efficiency solar cells for TRMM is far greater

  12. Straw man trade between multi-junction, gallium arsenide, and silicon solar cells

    Science.gov (United States)

    Gaddy, Edward M.

    1995-01-01

    Multi-junction (MJ), gallium arsenide (GaAs), and silicon (Si) solar cells have respective test efficiencies of approximately 24%, 18.5% and 14.8%. Multi-junction and gallium arsenide solar cells weigh more than silicon solar cells and cost approximately five times as much per unit power at the cell level. A straw man trade is performed for the TRMM spacecraft to determine which of these cell types would have offered an overall performance and price advantage to the spacecraft. A straw man trade is also performed for the multi-junction cells under the assumption that they will cost over ten times that of silicon cells at the cell level. The trade shows that the TRMM project, less the cost of the instrument, ground systems and mission operations, would spend approximately $552 thousand dollars per kilogram to launch and service science in the case of the spacecraft equipped with silicon solar cells. If these cells are changed out for gallium arsenide solar cells, an additional 31 kilograms of science can be launched and serviced at a price of approximately $90 thousand per kilogram. The weight reduction is shown to derive from the smaller area of the array and hence reductions in the weight of the array substrate and supporting structure. If the silicon solar cells are changed out for multi-junction solar cells, an additional 45 kilograms of science above the silicon base line can be launched and serviced at a price of approximately $58 thousand per kilogram. The trade shows that even if the multi-junction arrays are priced over ten times that of silicon cells, a price that is much higher than projected, that the additional 45 kilograms of science are launched and serviced at $182 thousand per kilogram. This is still much less than original $552 thousand per kilogram to launch and service the science. Data and qualitative factors are presented to show that these figures are subject to a great deal of uncertainty. Nonetheless, the benefit of the higher efficiency

  13. A Study of Hydrogen Anion Substitution in 1111-type Iron Arsenides

    Science.gov (United States)

    Hosono, Hideo

    2014-03-01

    Hydrogen is the simplest bipolar element and its valence state can be controlled from +1 to -1. We have synthesized the 1111-type iron arsenides CaFeAsH and LnFeAsO1 -xHx (Ln = lanthanide; 0 neutron diffraction and density functional theory calculations. The close similarity in the structural and electrical properties of CaFeAsH and CaFeAsF indicated the formation of the hydride ion (H -) , which is isovalent with the fluoride ion (F -) , in the 1111-type iron arsenides. When some of the O2 - ions in LnFeAsO are replaced by H -, superconductivity is induced by electron doping to the FeAs-layer to maintain charge neutrality. Since the substitution limit of hydrogen in LnFeAsO (x ~ 0.5) is much higher than that of fluorine (x ~ 0.2), the hydrogen substitution technique provides an effective pathway for high-density electron-doping, making it possible to draw the complete electronic phase diagram of LnFeAsO. The x-T diagrams of LnFeAsO1-xHx (Ln = La, Ce, Sm, Gd) have a wide superconducting (SC) region spanning the range x = 0.04 to 0.4, which is far from the parent antiferromagnetic region near x = 0.0. For LaFeAsO1-xHx, another SC dome region was found in the range x = ~ 0.2 to ~ 0.5 with a maximum Tc = 36 K, in addition to a conventional SC dome located at x ~ 0.08 with maximum Tc = 29 K. Density functional theory calculations performed for LaFeAsO1-xHx using virtual crystal approximation indicated that the newly observed Tc is correlated with the appearance of degeneration of the Fe 3d bands (dxy, dyz and dzx), which is caused not only by regularization of the tetrahedral shape of FeAs4 due to chemical pressure effects but also by selective band occupation with doped electrons. Very recently, a new AFM phase was found around x =0.5, suggesting that the double dome Tc structure reflects the presence of two AFM phases at x =0 and 0,5. In this talk, I review the recent progress in superconductivity in 1111-type iron (oxy)arsenides and related compounds induced by

  14. Aluminium alloys in municipal solid waste incineration bottom ash.

    Science.gov (United States)

    Hu, Yanjun; Rem, Peter

    2009-05-01

    With the increasing growth of incineration of household waste, more and more aluminium is retained in municipal solid waste incinerator bottom ash. Therefore recycling of aluminium from bottom ash becomes increasingly important. Previous research suggests that aluminium from different sources is found in different size fractions resulting in different recycling rates. The purpose of this study was to develop analytical and sampling techniques to measure the particle size distribution of individual alloys in bottom ash. In particular, cast aluminium alloys were investigated. Based on the particle size distribution it was computed how well these alloys were recovered in a typical state-of-the-art treatment plant. Assessment of the cast alloy distribution was carried out by wet physical separation processes, as well as chemical methods, X-ray fluorescence analysis and electron microprobe analysis. The results from laboratory analyses showed that cast alloys tend to concentrate in the coarser fractions and therefore are better recovered in bottom ash treatment plants.

  15. Oxygen–induced barrier height changes in aluminium – amorphous ...

    African Journals Online (AJOL)

    Se) films by exposing the samples to oxygen before the aluminium contacts were deposited. Current – voltage (I-V) measurements were carried out on the samples. The results show that the application of voltage causes charge exchange ...

  16. Tailored Aluminium based Coatings for Optical Appearance and Corrosion Resistance

    DEFF Research Database (Denmark)

    Aggerbeck, Martin

    The current project investigated the possibility of designing aluminium based coatings focusing on the effect of composition and surface finish on the optical appearance and on the alkaline corrosion properties using titanium as the main alloying element. The main results and discussions...... of these applications, but the use of recycled aluminium compromises this due to the presence of increased levels of impurity and alloying elements. Knowledge on how different alloying elements affect the optical appearance might therefore increase the applicability of recycled aluminium. It was investigated how...... the optical appearance is affected by the alloy composition, surface morphology, and the microstructure. Four commercial aluminium alloys were studied before and after polishing, etching, anodisation, and hot water sealing, giving an overview on how the alloy composition affects the appearance. It was found...

  17. The management of Frey's syndrome with aluminium chloride hexahydrate antiperspirant.

    OpenAIRE

    Black, M. J.; Gunn, A.

    1990-01-01

    Nine patients suffering from gustatory sweating (Frey's syndrome) following parotidectomy have been treated by topical applications of aluminium chloride hexahydrate. Treatment has successfully controlled gustatory sweating using application intervals varying from 1 to 50 days.

  18. The management of Frey's syndrome with aluminium chloride hexahydrate antiperspirant.

    Science.gov (United States)

    Black, M. J.; Gunn, A.

    1990-01-01

    Nine patients suffering from gustatory sweating (Frey's syndrome) following parotidectomy have been treated by topical applications of aluminium chloride hexahydrate. Treatment has successfully controlled gustatory sweating using application intervals varying from 1 to 50 days. Images Figure 1 PMID:2301903

  19. Deposition of aluminium nanoparticles using dense plasma focus device

    International Nuclear Information System (INIS)

    Devi, Naorem Bilasini; Srivastava, M P; Roy, Savita

    2010-01-01

    Plasma route to nanofabrication has drawn much attention recently. The dense plasma focus (DPF) device is used for depositing aluminium nanoparticles on n-type Si (111) wafer. The plasma chamber is filled with argon gas and evacuated at a pressure of 80 Pa. The substrate is placed at distances 4.0 cm, 5.0 cm and 6.0 cm from the top of the central anode. The aluminium is deposited on Si wafer at room temperature with two focused DPF shots. The deposits on the substrate are examined for their morphological properties using atomic force microscopy (AFM). The AFM images have shown the formation of aluminium nanoparticles. From the AFM images, it is found that the size of aluminium nanoparticles increases with increase in distance between the top of anode and the substrate for same number of DPF shots.

  20. Aluminium leaching from red mud by filamentous fungi.

    Science.gov (United States)

    Urík, Martin; Bujdoš, Marek; Milová-Žiaková, Barbora; Mikušová, Petra; Slovák, Marek; Matúš, Peter

    2015-11-01

    This contribution investigates the efficient and environmentally friendly aluminium leaching from red mud (bauxite residue) by 17 species of filamentous fungi. Bioleaching experiments were examined in batch cultures with the red mud in static, 7-day cultivation. The most efficient fungal strains in aluminium bioleaching were Penicillium crustosum G-140 and Aspergillus niger G-10. The A. niger G-10 strain was capable to extract up to approximately 141 mg·L(-1) of aluminium from 0.2 g dry weight red mud. Chemical leaching with organic acids mixture, prepared according to A. niger G-10 strain's respective fungal excretion during cultivation, proved that organic acids significantly contribute to aluminium solubilization from red mud. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Aluminium Roofing Products Ltd Marketing to the Public Sector, UK

    OpenAIRE

    Hosseini, Sadaf

    2009-01-01

    This management project was undertaken on behalf of Aluminium Roofing Products Ltd ™ (ARP), a young, entrepreneurial company associated predominantly with aluminium products. The project brief was initially untaken by Ian Dunbar - one of the marketing segmentation gurus in the UK. As a result of his investigation, the company aimed to target the public sector in the UK in order to increase their market share. The project was fairly broad and identified several areas of the public sector which...

  2. Adhesive Bonding of Aluminium Alloy A5754 by Epoxy Resins

    Directory of Open Access Journals (Sweden)

    Ivan Michalec

    2013-01-01

    Full Text Available Joining thin sheets of aluminium and its alloys is a promising area in the field of joining materials. Nowadays, joining methods that do not melt the material itself are increasingly being utilised. This paper deals with adhesive bonding of aluminium alloy A5754 by two-component epoxy resins. Theresults show that joints bonded by Hysol 9466 have appropriate mechanical properties, but that joints bonded by Hysol 9492 have better thermal stability.

  3. Numerical Modelling of Drawbeads for Forming of Aluminium Alloys

    OpenAIRE

    Joshi, Y; Christiansen, Peter; Masters, I; Bay, Niels Oluf; Dashwood, R

    2016-01-01

    The drawbeads in stamping tools are usually designed based on experience from the forming of steel. However, aluminium alloys display different forming behaviour to steels, which is not reflected in the drawbead design for tools used for stamping aluminium. This paper presents experimental results from different semi-circular drawbead geometries commonly encountered in automotive dies and compares them to those obtained from Stoughton’s analytical drawbead model and the 2D plane strain drawbe...

  4. Twenty years of isotope applications in the Hungarian aluminium industry

    International Nuclear Information System (INIS)

    Bujdoso, E.

    1982-01-01

    After a short review of the isotope techniques applied in the Hungarian aluminium industry some special applications and their results are briefly outlined. Industrial and laboratory scale trace constituent determinations, isotope and activation analytical methods and the application of sealed radiation sources are discussed. It has been shown that the related R+D activity followed closely the development trends of the aluminium industry. The references given is a comprehensive bibliography of Hungarian publications in this field. (author)

  5. Physiological Characterization of Kenyan Sorghum Lines for Tolerance To Aluminium

    OpenAIRE

    Cheprot, R. K.; Matonyei, T. K.; Maritim, K. K.; Were, B. A.; Dangasuk, O. G.; Onkware, A. O.; Gudu, S.

    2014-01-01

    Eighty nine Kenyan sorghum lines were screened for tolerance to aluminium toxicity in nutrient solution. Relative net root growth; root tip aluminium content and variation in organic acid exudation were used to determine the tolerance or sensitivity of the sorghum lines at 148 µM Al for six days. The lines showed variable reduction in root growth under the Al stress. On the basis of the relative net root growths, three lines were tolerant, nineteen were moderately tolerant and sixty seven wer...

  6. Influence of Chemical Composition on Porosity in Aluminium Alloys

    OpenAIRE

    Kucharčík L.; Brůna M.; Sládek A.

    2014-01-01

    Porosity is one of the major defects in aluminum castings, which results is a decrease of a mechanical properties. Porosity in aluminum alloys is caused by solidification shrinkage and gas segregation. The final amount of porosity in aluminium castings is mostly influenced by several factors, as amount of hydrogen in molten aluminium alloy, cooling rate, melt temperature, mold material, or solidification interval. This article deals with effect of chemical composition on porosity in Al-Si alu...

  7. Aluminium-rich corner in Al-Cu-La system

    International Nuclear Information System (INIS)

    Yunusov, I.; Ganiev, I.N.

    1990-01-01

    Aluminium corner of Al-Cu-La system are investigated by means of microstructural and differential thermal analysis. Existence of LaCu 2 Al 10 and LaCu 0.5 Al 3.5 ternary compounds in the system is confirmed and it is shown, as well, both compounds are in two-phase equilibrium with aluminium solid solution and form with it and between each other eutectic type state diagrams. State diagrams for quasibinary sections are plotted

  8. Gallium arsenide quantum well-based far infrared array radiometric imager

    Science.gov (United States)

    Forrest, Kathrine A.; Jhabvala, Murzy D.

    1991-01-01

    We have built an array-based camera (FIRARI) for thermal imaging (lambda = 8 to 12 microns). FIRARI uses a square format 128 by 128 element array of aluminum gallium arsenide quantum well detectors that are indium bump bonded to a high capacity silicon multiplexer. The quantum well detectors offer good responsivity along with high response and noise uniformity, resulting in excellent thermal images without compensation for variation in pixel response. A noise equivalent temperature difference of 0.02 K at a scene temperature of 290 K was achieved with the array operating at 60 K. FIRARI demonstrated that AlGaAS quantum well detector technology can provide large format arrays with performance superior to mercury cadmium telluride at far less cost.

  9. Cluster-Bethe-lattice treatment of the interstitial boron centre in irradiated gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Kleinert, P. (Akademie der Wissenschaften der DDR, Berlin. Zentralinstitut fuer Elektronenphysik)

    1984-08-01

    The radiation-induced interstitial defect B(1) in GaAs is theoretically analysed by a cluster-Bethe lattice treatment. Theoretical results obtained for a B-Ga dumbbell in gallium arsenide agree quite well with experimental data. The dumbbell coupling is about three times stiffer than the bonds between host-lattice atoms. The separation of the dumbbell atoms amounts to one lattice constant. Due to the isotopy of gallium atoms all B(1) bands should exhibit a double-peak structure with a small frequency split of about 1, 0.1, and 0.4 cm/sup -1/ for the A/sub 1/, B/sub 1/, and B/sub 2/ modes, respectively. A resolution of these splittings would supply additional evidence for the B(1) defect model discussed here.

  10. Self-cleaning and surface chemical reactions during hafnium dioxide atomic layer deposition on indium arsenide.

    Science.gov (United States)

    Timm, Rainer; Head, Ashley R; Yngman, Sofie; Knutsson, Johan V; Hjort, Martin; McKibbin, Sarah R; Troian, Andrea; Persson, Olof; Urpelainen, Samuli; Knudsen, Jan; Schnadt, Joachim; Mikkelsen, Anders

    2018-04-12

    Atomic layer deposition (ALD) enables the ultrathin high-quality oxide layers that are central to all modern metal-oxide-semiconductor circuits. Crucial to achieving superior device performance are the chemical reactions during the first deposition cycle, which could ultimately result in atomic-scale perfection of the semiconductor-oxide interface. Here, we directly observe the chemical reactions at the surface during the first cycle of hafnium dioxide deposition on indium arsenide under realistic synthesis conditions using photoelectron spectroscopy. We find that the widely used ligand exchange model of the ALD process for the removal of native oxide on the semiconductor and the simultaneous formation of the first hafnium dioxide layer must be significantly revised. Our study provides substantial evidence that the efficiency of the self-cleaning process and the quality of the resulting semiconductor-oxide interface can be controlled by the molecular adsorption process of the ALD precursors, rather than the subsequent oxide formation.

  11. A I-V analysis of irradiated Gallium Arsenide solar cells

    Science.gov (United States)

    Heulenberg, A.; Maurer, R. H.; Kinnison, J. D.

    1991-01-01

    A computer program was used to analyze the illuminated I-V characteristics of four sets of gallium arsenide (GaAs) solar cells irradiated with 1-MeV electrons and 10-MeV protons. It was concluded that junction regions (J sub r) dominate nearly all GaAs cells tested, except for irradiated Mitsubishi cells, which appear to have a different doping profile. Irradiation maintains or increases the dominance by J sub r. Proton irradiation increases J sub r more than does electron irradiation. The U.S. cells were optimized for beginning of life (BOL) and the Japanese for end of life (EOL). I-V analysis indicates ways of improving both the BOL and EOL performance of GaAs solar cells.

  12. Gallium arsenide solar cells-status and prospects for use in space

    Science.gov (United States)

    Brandhorst, H. W.; Flood, D.; Weinberg, I.

    1981-01-01

    Gallium Arsenide solar cells now equal or surpass the ubiquitous silicon solar cells in efficiency, radiation resistance, annealability, and in the capability for producing usable power output at elevated temperatures. NASA has developed a long-range research and development program to capitalize on these manifold advantages. In this paper we review the current state and future prospects for R&D in this promising solar cell material, and indicate the progress being made toward development of GaAs cells suitable for a variety of space missions. Results are presented from studies which demonstrate conclusively that GaAs cells can provide a net mission cost and weight savings for certain important mission classes.

  13. Advances in gallium arsenide monolithic microwave integrated-circuit technology for space communications systems

    Science.gov (United States)

    Bhasin, K. B.; Connolly, D. J.

    1986-01-01

    Future communications satellites are likely to use gallium arsenide (GaAs) monolithic microwave integrated-circuit (MMIC) technology in most, if not all, communications payload subsystems. Multiple-scanning-beam antenna systems are expected to use GaAs MMIC's to increase functional capability, to reduce volume, weight, and cost, and to greatly improve system reliability. RF and IF matrix switch technology based on GaAs MMIC's is also being developed for these reasons. MMIC technology, including gigabit-rate GaAs digital integrated circuits, offers substantial advantages in power consumption and weight over silicon technologies for high-throughput, on-board baseband processor systems. In this paper, current developments in GaAs MMIC technology are described, and the status and prospects of the technology are assessed.

  14. Ultraviolet Beam Focusing in Gallium Arsenide by Direct Excitation of Surface Plasmon Polaritons

    Directory of Open Access Journals (Sweden)

    Senfeng Lai

    2015-01-01

    Full Text Available This paper proposed that ultraviolet beam could be focused by gallium arsenide (GaAs through direct excitation of surface plasmon polaritons. Both theoretical analysis and computer simulation showed that GaAs could be a reasonably good plasmonic material in the air in the deep ultraviolet waveband. With a properly designed bull’s eye structure etched in GaAs, the ultraviolet electric field could be enhanced to as high as 20 times the incident value, and the full-width-half-maximum (FWHM of the light beam could be shrunk from ~48° to ~6°. As a plasmonic material, GaAs was compared to Ag and Al. Within the studied ultraviolet waveband, the field enhancement in GaAs was much stronger than Ag but not as high as Al.

  15. Induced superconductivity in high-mobility two-dimensional electron gas in gallium arsenide heterostructures.

    Science.gov (United States)

    Wan, Zhong; Kazakov, Aleksandr; Manfra, Michael J; Pfeiffer, Loren N; West, Ken W; Rokhinson, Leonid P

    2015-06-11

    Search for Majorana fermions renewed interest in semiconductor-superconductor interfaces, while a quest for higher-order non-Abelian excitations demands formation of superconducting contacts to materials with fractionalized excitations, such as a two-dimensional electron gas in a fractional quantum Hall regime. Here we report induced superconductivity in high-mobility two-dimensional electron gas in gallium arsenide heterostructures and development of highly transparent semiconductor-superconductor ohmic contacts. Supercurrent with characteristic temperature dependence of a ballistic junction has been observed across 0.6 μm, a regime previously achieved only in point contacts but essential to the formation of well separated non-Abelian states. High critical fields (>16 T) in NbN contacts enables investigation of an interplay between superconductivity and strongly correlated states in a two-dimensional electron gas at high magnetic fields.

  16. Bowtie nanoantenna integrated with indium gallium arsenide antimonide for uncooled infrared detector with enhanced sensitivity.

    Science.gov (United States)

    Choi, Sangjo; Sarabandi, Kamal

    2013-12-10

    A novel high-impedance nanoantenna with an embedded matching network is implemented to realize a highly sensitive infrared detector. A bowtie antenna is operated at its antiparallel resonance and loaded with a small low-bandgap (E(g)=0.52  eV) indium gallium arsenide antimonide (InGaAsSb) p-n junction. The structure is optimized for maximum power transfer and significant field enhancement at its terminals for a desired frequency band where the maximum quantum efficiency of InGaAsSb is observed. The sensitivity improvement of the proposed detector is evaluated against the traditional bulk detector and it is shown that the detectivity is improved by the field enhancement factor, which is approximately 20 for the case considered here.

  17. Direct observation of the orbital spin Kondo effect in gallium arsenide quantum dots

    Science.gov (United States)

    Shang, Ru-Nan; Zhang, Ting; Cao, Gang; Li, Hai-Ou; Xiao, Ming; Guo, Guang-Can; Guo, Guo-Ping

    2018-02-01

    Besides the spin Kondo effect, other degrees of freedom can give rise to the pseudospin Kondo effect. We report a direct observation of the orbital spin Kondo effect in a series-coupled gallium arsenide (GaAs) double quantum dot device where orbital degrees act as pseudospin. Electron occupation in both dots induces a pseudospin Kondo effect. In a region of one net spin impurity, complete spectra with three resonance peaks are observed. Furthermore, we observe a pseudo-Zeeman effect and demonstrate its electrical controllability for the artificial pseudospin in this orbital spin Kondo process via gate voltage control. The fourfold degeneracy point is realized at a specific value supplemented by spin degeneracy, indicating a transition from the SU(2) to the SU(4) Kondo effect.

  18. Two stream instability in n-type gallium arsenide semiconductor quantum plasma

    Science.gov (United States)

    Ghosh, S.; Muley, Apurva

    2018-01-01

    By using quantum hydrodynamic model, we derive a generalized dielectric response function for two stream instability (convective only) in n-type gallium arsenide semiconductor plasma. We investigate the phase and amplification profiles of two stream instability with externally applied electric field ranging from 2600 to 4000 kV m-1 in presence of non-dimensional quantum parameter- H. In this range, a significant number of electrons in satellite valley become comparable to the number of electrons in central valley. The presence of quantum corrections in plasma medium induces two novel modes; one of it has amplifying nature and propagates in forward direction. It also modifies the spectral profile of four pre-existing modes in classical plasma. The existence of two stream instability is also established analytically by deriving the real part of longitudinal electrokinetic power flow density.

  19. Atomistic simulation studies of iron sulphide, platinum antimonide and platinum arsenide

    CSIR Research Space (South Africa)

    Ngoepe, PE

    2005-09-01

    Full Text Available studies of iron sulphide, platinum antimonide and platinum arsenide P.E. Ngoepea,b*, P.S. Ntoahaea, S.S. Mangwejanea, H.M. Sitholec, S.C. Parkerd, K.V. Wrighte and N.H. de Leeuwf Introduction Metal sulphide minerals are of industrial significance because...?S) 2.179 2.177 2.703 2.670 2.361 2.381 Me?X 2.269 2.262 2.678 2.642 2.468 2.495 Elastic constants (GPa) C11 352.6 366.0 265.8 266.0 341.9 355.5+ C44 101.7 105.0 59.17 59.05 97.80 84.93+ C12 47.91 47.00 67.87 68.00 74.10 49.60+ Bulk modulus (GPa) B 149...

  20. Ultrafast photocurrents and terahertz radiation in gallium arsenide and carbon based nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Prechtel, Hans Leonhard

    2011-08-15

    In this thesis we developed a measurement technique based on a common pump-probe scheme and coplanar stripline circuits that enables time-resolved photocurrent measurements of contacted nanosystems with a micrometer spatial and a picosecond time resolution. The measurement technique was applied to lowtemperature grown gallium arsenide (LT-GaAs), carbon nanotubes (CNTs), graphene, and p-doped gallium arsenide (GaAs) nanowires. The various mechanisms responsible for the generation of current pulses by pulsed laser excitation were reviewed. Furthermore the propagation of the resulting electromagnetic radiation along a coplanar stripline circuit was theoretically and numerically treated. The ultrafast photocurrent response of low-temperature grown GaAs was investigated. We found two photocurrent pulses in the time-resolved response. We showed that the first pulse is consistent with a displacement current pulse. We interpreted the second pulse to result from a transport current process. We further determined the velocity of the photo-generated charge carriers to exceed the drift, thermal and quantum velocities of single charge carriers. Hereby, we interpreted the transport current pulse to stem from an electron-hole plasma excitation. We demonstrated that the photocurrent response of CNTs comprises an ultrafast displacement current and a transport current. The data suggested that the photocurrent is finally terminated by the recombination lifetime of the charge carriers. To the best of our knowledge, we presented in this thesis the first recombination lifetime measurements of contacted, suspended, CVD grown CNT networks. In addition, we studied the ultrafast photocurrent dynamics of freely suspended graphene contacted by metal electrodes. At the graphene-metal interface, we demonstrated that built-in electric fields give rise to a photocurrent with a full-width-half-maximum of a few picoseconds and that a photo-thermoelectric effect generates a current with a decay time

  1. Lake restoration with aluminium, bentonite and Phoslock: the effect on sediment stability and light attenuation

    DEFF Research Database (Denmark)

    Egemose, Sara; Reitzel, Kasper; Flindt, Mogens

    treatments on aluminium mobility, sediment stability or light climate. A laboratory flume experiment including three shallow Danish lakes was conducted. We measured the effects of aluminium, Phoslock (a commercial product), bentonite, and a combination of bentonite/aluminium. Each treatment caused a varying...... consolidation of the sediment. The largest consolidation occurred using Phoslock- and bentonite-addition followed by bentonite/aluminium-addition, whereas aluminium alone had no effect. Sediment stability thresholds were measured before and after addition. Especially Phoslock, but also bentonite and bentonite....../aluminium increased sediment erosion threshold, with respectively 200%, 43% and 57%. Aluminium, bentonite/aluminium, and Phoslock improved the light conditions in the water phase, with respectively 60%, 57% and 50%, whereas bentonite created higher turbidity. Conclusively aluminium improved the light conditions...

  2. The binding, transport and fate of aluminium in biological cells.

    Science.gov (United States)

    Exley, Christopher; Mold, Matthew J

    2015-04-01

    Aluminium is the most abundant metal in the Earth's crust and yet, paradoxically, it has no known biological function. Aluminium is biochemically reactive, it is simply that it is not required for any essential process in extant biota. There is evidence neither of element-specific nor evolutionarily conserved aluminium biochemistry. This means that there are no ligands or chaperones which are specific to its transport, there are no transporters or channels to selectively facilitate its passage across membranes, there are no intracellular storage proteins to aid its cellular homeostasis and there are no pathways which evolved to enable the metabolism and excretion of aluminium. Of course, aluminium is found in every compartment of every cell of every organism, from virus through to Man. Herein we have investigated each of the 'silent' pathways and metabolic events which together constitute a form of aluminium homeostasis in biota, identifying and evaluating as far as is possible what is known and, equally importantly, what is unknown about its uptake, transport, storage and excretion. Copyright © 2014 Elsevier GmbH. All rights reserved.

  3. Effect of iron and silicon in aluminium and its alloys

    International Nuclear Information System (INIS)

    Kovacs, I.

    1990-01-01

    The iron and silicon are the main impurities in aluminium, they are always present in alloys made from commercially pure base material. The solid solubility of iron in aluminium is very low, therefore its largest amount forms intermetallic compounds the kind of which depends strongly on the other impurities of alloying elements. Although the solid solubility of silicon is much larger than that of the iron, it is the constituent of both the primary and the secondary particles, the structure of which depends in general on the iron-silicon concentration ratio. These Fe and Si containing particles can cause various and basic changes in the macroscopic properties of the alloy. Since commercially pure aluminium has extensive consumer and industrial use, it is very important to know, not only from scientific but also from practical point of view, the effect of iron and silicon on the physical and mechanical properties of aluminium and its alloys. The aim of the ''International Workshop on the Effect of Iron and Silicon in Aluminium and its Alloys'' was to clarify the present knowledge on this subject. The thirty papers presented at the Workshop and collected in this Proceedings cover many important fields of the subject. I hope that they will contribute to both the deeper understanding of the related phenomena and the improvement of technologies for producing better aluminium alloys

  4. Compressive Behaviour and Energy Absorption of Aluminium Foam Sandwich

    Science.gov (United States)

    Endut, N. A.; Hazza, M. H. F. Al; Sidek, A. A.; Adesta, E. T. Y.; Ibrahim, N. A.

    2018-01-01

    Development of materials in automotive industries plays an important role in order to retain the safety, performance and cost. Metal foams are one of the idea to evolve new material in automotive industries since it can absorb energy when it deformed and good for crash management. Recently, new technology had been introduced to replace metallic foam by using aluminium foam sandwich (AFS) due to lightweight and high energy absorption behaviour. Therefore, this paper provides reliable data that can be used to analyze the energy absorption behaviour of aluminium foam sandwich by conducting experimental work which is compression test. Six experiments of the compression test were carried out to analyze the stress-strain relationship in terms of energy absorption behavior. The effects of input variables include varying the thickness of aluminium foam core and aluminium sheets on energy absorption behavior were evaluated comprehensively. Stress-strain relationship curves was used for energy absorption of aluminium foam sandwich calculation. The result highlights that the energy absorption of aluminium foam sandwich increases from 12.74 J to 64.42 J respectively with increasing the foam and skin thickness.

  5. Surface roughness when diamond turning RSA 905 optical aluminium

    Science.gov (United States)

    Otieno, T.; Abou-El-Hossein, K.; Hsu, W. Y.; Cheng, Y. C.; Mkoko, Z.

    2015-08-01

    Ultra-high precision machining is used intensively in the photonics industry for the production of various optical components. Aluminium alloys have proven to be advantageous and are most commonly used over other materials to make various optical components. Recently, the increasing demand from optical systems for optical aluminium with consistent material properties has led to the development of newly modified grades of aluminium alloys produced by rapid solidification in the foundry process. These new aluminium grades are characterised by their finer microstructures and refined mechanical and physical properties. However the machining database of these new optical aluminium grades is limited and more research is still required to investigate their machinability performance when they are diamond turned in ultrahigh precision manufacturing environment. This work investigates the machinability of rapidly solidified aluminium RSA 905 by varying a number of diamond-turning cutting parameters and measuring the surface roughness over a cutting distance of 4 km. The machining parameters varied in this study were the cutting speed, feed rate and depth of cut. The results showed a common trend of decrease in surface roughness with increasing cutting distance. The lowest surface roughness Ra result obtained after 4 km in this study was 3.2 nm. This roughness values was achieved using a cutting speed of 1750 rpm, feed rate of 5 mm/min and depth of cut equal to 25 μm.

  6. Investigation of different anode materials for aluminium rechargeable batteries

    Science.gov (United States)

    Muñoz-Torrero, David; Leung, Puiki; García-Quismondo, Enrique; Ventosa, Edgar; Anderson, Marc; Palma, Jesús; Marcilla, Rebeca

    2018-01-01

    In order to shed some light into the importance of the anodic reaction in reversible aluminium batteries, we investigate here the electrodeposition of aluminium in an ionic liquid electrolyte (BMImCl-AlCl3) using different substrates. We explore the influence of the type of anodic material (aluminium, stainless steel and carbon) and its 3D geometry on the reversibility of the anodic reaction by cyclic voltammetry (CV) and galvanostatic charge-discharge. The shape of the CVs confirms that electrodeposition of aluminium was feasible in the three materials but the highest peak currents and smallest peak separation in the CV of the aluminium anode suggested that this material was the most promising. Interestingly, carbon-based substrates appeared as an interesting alternative due to the high peak currents in CV, moderate overpotentials and dual role as anode and cathode. 3D substrates such as fiber-based carbon paper and aluminium mesh showed significantly smaller overpotentials and higher efficiencies for Al reaction suggesting that the use of 3D substrates in full batteries might result in enhanced power. This is corroborated by polarization testing of full Al-batteries.

  7. Effects of Aluminium Sulfate on Cadmium Accumulation in Rice

    International Nuclear Information System (INIS)

    Khamvarn, Vararas; Boontanon, Narin; Prapagdee, Benjaphorn; Kumsopa, Acharaporn; Boonsirichai, Kanokporn

    2011-06-01

    Full text: Cadmium accumulation in Pathum Thani 1 and Suphan Buri 60 rice cultivars was investigated upon treatment with aluminium sulfate as a precipitant. Rice was grown hydroponically in a medium containing 4 ppm cadmium nitrate with or without 4 ppm aluminium sulfate. Root, stem with leaves and grain samples were collected and analyzed for cadmium content using atomic absorption spectroscopy and inductively coupled plasma atomic emission spectroscopy. Without the addition of aluminium sulfate, Pathum Thani 1 and Suphan Buri 60 accumulated 24.71∫ 3.14 ppm and 34.43 ∫ 4.51 ppm (dry weight of whole plant) of cadmium, respectively. With aluminium sulfate, cadmium accumulation increased to 40.66 ∫ 2.47 ppm and 62.94 ∫ 10.69 ppm, respectively. The addition of aluminium sulfate to the planting medium did not reduce cadmium accumulation but caused the rice to accumulate more cadmium especially in the shoots and grains. This observation might serve as the basis for future research on the management of agricultural areas that are contaminated with cadmium and aluminium

  8. Irradiation effects on aluminium and beryllium

    International Nuclear Information System (INIS)

    Bieth, M.

    1992-01-01

    The High Flux Reactor (HFR) in Petten (The Netherlands) is a 45 MW light water cooled and moderated research reactor. The vessel was replaced in 1984 after more than 20 years of operation because doubts had arisen over the condition of the aluminium alloy construction material. Data on the mechanical properties of the aluminium alloy Al 5154 with and without neutron irradiation are necessary for the safety analysis of the new HFR vessel which is constructed from the same material as the old vessel. Fatigue, fracture mechanics (crack growth and fracture toughness) and tensile properties have been obtained from several experimental testing programmes with materials of the new and the old HFR vessel. 1) Low-cycle fatigue testing has been carried out on non-irradiated specimens from stock material of the new HFR vessel. The number of cycles to failure ranges from 90 to more than 50,000 for applied strain from 3.0% to 0.4%; 2) Fatigue crack growth rate testing has been conducted: - with unirradiated specimens from stock material of the new vessel; - with irradiated specimens from the remnants of the old core box. Irradiation has a minor effect on the sub-critical fatigue crack growth rate. The ultimate increase of the mean crack growth rate amounts to a factor of 2. However crack extension is strongly reduced due to the smaller crack length for crack growth instability (reduction of K IC ). - Irradiated material from the core box walls of the old vessel has been used for fracture toughness testing. The conditional fracture toughness values K IQ ranges from 30.3 down to 16.5 MPa√m. The lowermost meaningful 'K IC ' is 17.7 MPa√m corresponding to the thermal fluence of 7.5 10 26 n/m 2 for the End of Life (EOL) of the old vessel. - Testing carried out on irradiated material from the remnants of the old HFR core box shows an ultimate neutron irradiation hardening of 35 points increase of HSR 15N and an ultimate tensile yield stress of 589 MPa corresponding to the

  9. In-Plane Electronic Anisotropy of Underdoped ___122___ Fe-Arsenide Superconductors Revealed by Measurements of Detwinned Single Crystals

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Ian Randal

    2012-05-08

    The parent phases of the Fe-arsenide superconductors harbor an antiferromagnetic ground state. Significantly, the Neel transition is either preceded or accompanied by a structural transition that breaks the four fold symmetry of the high-temperature lattice. Borrowing language from the field of soft condensed matter physics, this broken discrete rotational symmetry is widely referred to as an Ising nematic phase transition. Understanding the origin of this effect is a key component of a complete theoretical description of the occurrence of superconductivity in this family of compounds, motivating both theoretical and experimental investigation of the nematic transition and the associated in-plane anisotropy. Here we review recent experimental progress in determining the intrinsic in-plane electronic anisotropy as revealed by resistivity, reflectivity and ARPES measurements of detwinned single crystals of underdoped Fe arsenide superconductors in the '122' family of compounds.

  10. Bioaccumulation of Aluminium in Hydromacrophytes in Polish Coastal Lakes

    Directory of Open Access Journals (Sweden)

    Senze Magdalena

    2015-03-01

    Full Text Available The research on aluminium content was conducted in water and on aquatic flora of Polish lakes in the central part of the coast. The study included the lakes Sarbsko, Choczewskie, Bia.e, K.odno, D.brze and Salino investigated in the summer of 2013. The examined lakes belong mainly to the direct basin of the Baltic Sea. Samples of aquatic plants and lake waters were collected. In the water samples pH and electrolytic conductivity were measured. The aluminium content was determined both in water and aquatic plants. Submerged hydromacrophyte studies included Myriophyllum alterniflorum L., Potamogeton perfoliatus L. and Ceratophyllum demersum L. Emergent hydromacrophyte studies included Phragmites australis (Cav. Trin. ex Steud., Juncus bulbosus L., Iris pseudacorus L., Eleocharis palustris (L. Roem. % Schult., Phalaris arundinacea L., Carex riparia Curt., Mentha aquatic L., Stratiotes aloides L., Alisma plantago-aquatica L., Glyceria maxima (Hartman Holmb., Sagittaria sagittifolia L., Scirpus lacustris L. and Typha angustifolia L. The purpose of this investigation was the determination of the aluminium content in submerged and emergent hydromacrophytes and also the definition of their bioaccumulative abilities. The average concentration of aluminium in water was 2.68 fęg Al dm.3. The average content of aluminium in plants was 2.8015 mg Al kg.1. The bioaccumulation factor ranged from BCF=19.74 to BCF=16619. On the basis of the analysis of the aluminium content in water and aquatic plants results show that both water and plants were characterized by a moderate level of aluminium. The recorded concentrations indicate a mid-range value and are much lower than those which are quoted for a variety of surface waters in various parts of the world.

  11. Accumulation and toxicity of aluminium-contaminated food in the freshwater crayfish, Pacifastacus leniusculus.

    Science.gov (United States)

    Woodburn, Katie; Walton, Rachel; McCrohan, Catherine; White, Keith

    2011-10-01

    The accumulation and toxicity of aluminium in freshwater organisms have primarily been examined following aqueous exposure. This study investigated the uptake, excretion and toxicity of aluminium when presented as aluminium-contaminated food. Adult Pacifastacus leniusculus were fed control (3 μg aluminium/g) or aluminium-spiked pellets (420 μg aluminium/g) over 28 days. Half the crayfish in each group were then killed and the remainder fed control pellets for a further 10 days (clearance period). Concentrations of aluminium plus the essential metals calcium, copper, potassium and sodium were measured in the gill, hepatopancreas, flexor muscle, antennal gland (kidney) and haemolymph. Histopathological analysis of tissue damage and sub-cellular distribution of aluminium were examined in the hepatopancreas. Haemocyte number and protein concentration in the haemolymph were analysed as indicators of toxicity. The hepatopancreas of aluminium-fed crayfish contained significantly more aluminium than controls on days 28 and 38, and this amount was positively correlated with the amount ingested. More than 50% of the aluminium in the hepatopancreas of aluminium-fed crayfish was located in sub-cellular fractions thought to be involved in metal detoxification. Aluminium concentrations were also high in the antennal glands of aluminium-fed crayfish suggesting that some of the aluminium lost from the hepatopancreas is excreted. Aluminium exposure via contaminated food caused inflammation in the hepatopancreas but did not affect the number of circulating haemocytes, haemolymph ion concentrations or protein levels. In conclusion, crayfish accumulate, store and excrete aluminium from contaminated food with only localised toxicity. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Boron Arsenide and Boron Phosphide for High Temperature and Luminescent Devices. [semiconductor devices - crystal growth/crystal structure

    Science.gov (United States)

    Chu, T. L.

    1975-01-01

    The crystal growth of boron arsenide and boron phosphide in the form of bulk crystals and epitaxial layers on suitable substrates is discussed. The physical, chemical, and electrical properties of the crystals and epitaxial layers are examined. Bulk crystals of boron arsenide were prepared by the chemical transport technique, and their carrier concentration and Hall mobility were measured. The growth of boron arsenide crystals from high temperature solutions was attempted without success. Bulk crystals of boron phosphide were also prepared by chemical transport and solution growth techniques. Techniques required for the fabrication of boron phosphide devices such as junction shaping, diffusion, and contact formation were investigated. Alloying techniques were developed for the formation of low-resistance ohmic contacts to boron phosphide. Four types of boron phosphide devices were fabricated: (1) metal-insulator-boron phosphide structures, (2) Schottky barriers; (3) boron phosphide-silicon carbide heterojunctions; and (4) p-n homojunctions. Easily visible red electroluminescence was observed from both epitaxial and solution grown p-n junctions.

  13. Oral co-administration of α-lipoic acid, quercetin and captopril prevents gallium arsenide toxicity in rats.

    Science.gov (United States)

    Bhatt, Kapil; Flora, S J S

    2009-07-01

    Gallium arsenide (GaAs), an inter-metallic semiconductor, known to exhibit superior optical and electronic properties compared to silicon, promotes its use in semiconductor industries. Extensive use of GaAs will inevitably lead to an increase in the exposure of workers manufacturing these products. Antioxidants are exogenous or endogenous compounds acting in several ways, including scavenging reactive oxygen species (ROS) or their precursors, inhibiting ROS formation, and binding metal ions needed for the catalysis of ROS generation. In the present study we investigated the protective efficacy of α-lipoic acid, quercetin and captopril individually against gallium arsenide exposure. Co-administration of α-lipoic acid with GaAs was most effective in reducing GaAs induced inhibition of blood δ-aminolevulinic acid dehydratase (ALAD) activity, liver, kidney and brain reduced glutathione (GSH) level and elevation of oxidized glutathione (GSSG). Captopril, on the other hand was effective in reducing thiobarbituric acid reactive substance (TBARS) levels, while quercetin reduced ROS in liver and kidney. The results suggest comparatively better preventive efficacy of concomitant α-lipoic acid administration during Gallium arsenide exposure compared to quercetin and captopril in preventing GaAs induced oxidative stress. Copyright © 2009 Elsevier B.V. All rights reserved.

  14. SUPERPLASTIC BEHAVIOUR IN DYNAMICALLY RECRYSTALLISING ALUMINIUM ALLOYS

    Directory of Open Access Journals (Sweden)

    R AMICHI

    1999-12-01

    Full Text Available Aluminium alloys can be thermomechanically processed to develop the grain fine microstructures required for superplasticity by either static recrystallisation prior to superplastic forming (SPF or by dynamic recrystallisation during the early stages of deformation. The present work has examined and compared the superplastic behaviour and the microstructural evolution in Al-Li alloys (8090 sheet material processed by the second route for a wide range of temperatures and strain-rates.  It was observed that the material showed a high potential for superplastic flow. Although significant superplasticity was observed at temperature of 400°C and below. The reasons for the high resistance of the material to strain localisation are discussed.  It was noted that ductility enhancement could also be achieved by the control of the strain-rate path. A rapid pre-strain improved significantly the subsequent superplastic elongation to failure at optimum strain rate.  Further enhancement has been obtained by pre-straining at constant velocity following by deformation to failure at lower constant velocity. The microstructure changes prior or during deformation were also examined.

  15. Methemoglobinemia in aluminium phosphide poisoning in rats.

    Science.gov (United States)

    Lall, S B; Peshin, S S; Mitra, S

    2000-01-01

    Aluminium phosphide (AlP) a grain fumigant is the leading cause of intentional poisoning in North India. The mechanisms involved in toxicity are not known and there is no antidote till date. The present study was carried out to investigate the oxygen free radical generation, methemoglobinemia and effect of methylene blue treatment on survival time in rat model of AlP poisoning. AlP (50 mg/kg, intragastric) was administered in one group and the other group received AlP + Methylene Blue (MB) (0.1%, 1 mg/kg/5 min, i.v.). Malonyldialdehyde (MDA) and methemoglobin (MeHb) levels were measured at 10 and 30 min intervals. Blood MDA levels increased at 10 and 30 min after AlP exposure with simultaneous rise in MeHb levels suggesting methemoglobinemia could be due to increased oxygen free radical generation. Methylene blue caused a significant fall in both the parameters with prolongation of survival time. It is concluded that AlP causes methemoglobinemia responding to methylene blue treatment.

  16. Acute aluminium phosphide poisoning, what is new?

    Directory of Open Access Journals (Sweden)

    Yatendra Singh

    2014-01-01

    Full Text Available Aluminium phosphide (AlP is a cheap solid fumigant and a highly toxic pesticide that is commonly used for grain preservation. AlP has currently generated interest with increasing number of cases in the past four decades because of its increased use for agricultural and nonagricultural purposes, and also its easy availability in the markets has led to its increased misuse to commit suicide. Ingestion is usually suicidal in intent, uncommonly accidental and rarely homicidal. The poison affects all systems, shock, cardiac arrhythmias with varied ECG changes and gastrointestinal features being the most prominent. Diagnosis is made on the basis of clinical suspicion, a positive silver nitrate paper test to phosphine, and gastric aspirate and viscera biochemistry. Treatment includes early gastric lavage with potassium permanganate or a combination of coconut oil and sodium bicarbonate, administration of charcoal and palliative care. Specific therapy includes intravenous magnesium sulphate and oral coconut oil. Unfortunately, the lack of a specific antidote Results in very high mortality and the key to treatment lies in rapid decontamination and institution of resuscitative measures. This article aims to identify the salient features and mechanism of AlP poisoning along with its management strategies and prognostic variables.

  17. Design of Grain Refiners for Aluminium Alloys

    Science.gov (United States)

    Tronche, A.; Greer, A. L.

    The efficiency of a grain refiner can be quantified as the number of grains per nucleant particle in the solidified product. Even for effective refiners in aluminium, such as Al-5Ti-1B, it is known from experiments that efficiencies are very low, at best 10-3 to 102. It is of interest to explore the reasons for such low values, and to assess the prospects for increased efficiency though design of refiners. Recently it has been shown [1] that a simple recalescence-based model can make quantitative predictions of grain size as a function of refiner addition level, cooling rate and solute content. In the model, the initiation of grains is limited by the free growth from nucleant particles, the size distribution of which is very important. The present work uses this model as the basis for discussing the effect of particle size distribution on grain refiner performance. Larger particles (of TiB2 in the case of present interest) promote greater efficiency, as do narrower size distributions. It is shown that even if the size distribution could be exactly specified, compromises would have to be made to balance efficiency (defined as above) with other desirable characteristics of a refiner.

  18. Fabrication experience of aluminium clad aluminium matrix dispersion fuels at BARC

    International Nuclear Information System (INIS)

    Ganguly, C.; Hedge, P.W.; Prasad, G.J.

    1995-01-01

    Aluminium clad, aluminium matrix plate type dispersion fuels have been fabricated in BARC in recent years as part of fuel development programme for small non-power research reactors. The present paper describes the flowsheet developed for fabrication of Al-UAl x , Al-U 3 Si 2 and Al-U 3 O 8 fuels at BARC. The Al-20% U alloy fuel for KAMINI neutron radiography reactor was prepared by 'melting and casting' route, followed by picture framing and roll-bonding. For higher 'U' density fuels namely, Al-UAl x , Al-U 3 O 8 and Al-U 3 Si 2 the 'powder metallurgy' route was followed for preparation of fuel meat. The novel features in fabrication route were: addition of Zr for stabilizing UAl 3 phase in Al-20% U alloy; x-ray radiography and microdensitometric scanning of radiographs for location of fuel outline inside fuel element and for confirming homogeneous distribution of fissile atoms; immersion ultrasonic testing for confirming good bonding between mating Al surface of the fuel plate. (author)

  19. Aluminium Matrix Composites Reinforced with Co-continuous Interlaced Phases Aluminium-alumina Needles

    Directory of Open Access Journals (Sweden)

    Elvio de Napole Gregolin

    2002-09-01

    Full Text Available An Al-5SiO2 (5 wt% of SiO2 aluminium matrix fiber composite was produced where the reinforcement consists of fossil silica fibers needles. After being heat-treated at 600 °C, the original fiber morphology was retained but its microstructure changed from solid silica to an interconnected (Al-Si/Al2O3 interlaced structure named co-continuous composite. A technique of powder metallurgy, using commercial aluminium powder and the silica fibers as starting materials, followed by hot extrusion, was used to produce the composite. The co-continuous microstructure was obtained partially or totally on the fibers as a result of the reaction, which occurs during the heat treatment, first by solid diffusion and finally by the liquid Al-Si in local equilibrium, formed with the silicon released by reaction. The internal structure of the fibers was characterized using field emission electron microscope (FEG-SEM and optical microscopy on polished and fractured samples.

  20. Microstructure and properties of aluminium-aluminium oxide graded composite materials

    Science.gov (United States)

    Kamaruzaman, F. F.; Nuruzzaman, D. M.; Ismail, N. M.; Hamedon, Z.; Iqbal, A. K. M. A.; Azhari, A.

    2018-03-01

    In this research works, four-layered aluminium-aluminium oxide (Al-Al2O3) graded composite materials were fabricated using powder metallurgy (PM) method. In processing, metal-ceramic graded composite materials of 0%, 10%, 20% and 30% weight percentage of ceramic concentration were prepared under 30 ton compaction load using a cylindrical die-punch set made of steel. After that, two-step pressureless sintering was carried out at sintering temperature and time 600°C and 3 hours respectively. It was observed that the sintered cylindrical specimens of 30 mm diameter were prepared successfully. The graded composite specimens were analysed and the properties such as density, microstructure and hardness were measured. It was found that after sintering process, the diameter of the graded cylindrical structure was decreased. Using both Archimedes method and rule of mixture (ROM), he density of structure was measured. The obtained results revealed that the microvickers hardness was increased as the ceramic component increases in the graded layer. Moreover, it was observed that the interface of the graded structure is clearly distinguished within the multilayer stack and the ceramic particles are almost uniformly distributed in the Al matrix.

  1. Aluminium concentration versus the base cation to aluminium ratio as predictors for aluminium toxicity in Pinus sylvestris and Picea abies seedlings

    NARCIS (Netherlands)

    Schöll, van L.; Keltjens, W.G.; Hoffland, E.; Breemen, van N.

    2004-01-01

    Aluminium (Al) toxicity is considered an important factor in forest deterioration caused by soil acidification. A ratio of base cations (BC) to Al in the soil solution lower than 1 is widely used as an indicator for potentially adverse effects on tree health. In our view, the validity of the

  2. Photodynamic effect of aluminium and zinc tetrasulfophthalocyanines on melanoma cancer cells

    CSIR Research Space (South Africa)

    Maduray, K

    2010-06-01

    Full Text Available Aluminium and zinc tetrasulfophthalocyanines were activated with a 672nm wavelength laser to investigate the photodynamic effects on melanoma cancer, dermal fibroblast and epidermal keratinocyte cells. Aluminium tetrasulfophthalocyanine was more...

  3. AE Monitoring of Diamond Turned Rapidly Soldified Aluminium 443

    International Nuclear Information System (INIS)

    Onwuka, G; Abou-El-Hossein, K; Mkoko, Z

    2017-01-01

    The fast replacement of conventional aluminium with rapidly solidified aluminium alloys has become a noticeable trend in the current manufacturing industries involved in the production of optics and optical molding inserts. This is as a result of the improved performance and durability of rapidly solidified aluminium alloys when compared to conventional aluminium. Melt spinning process is vital for manufacturing rapidly solidified aluminium alloys like RSA 905, RSA 6061 and RSA 443 which are common in the industries today. RSA 443 is a newly developed alloy with few research findings and huge research potential. There is no available literature focused on monitoring the machining of RSA 443 alloys. In this research, Acoustic Emission sensing technique was applied to monitor the single point diamond turning of RSA 443 on an ultrahigh precision lathe machine. The machining process was carried out after careful selection of feed, speed and depths of cut. The monitoring process was achieved with a high sampling data acquisition system using different tools while concurrent measurement of the surface roughness and tool wear were initiated after covering a total feed distance of 13km. An increasing trend of raw AE spikes and peak to peak signal were observed with an increase in the surface roughness and tool wear values. Hence, acoustic emission sensing technique proves to be an effective monitoring method for the machining of RSA 443 alloy. (paper)

  4. The structure of high-quality aluminium cast iron

    Directory of Open Access Journals (Sweden)

    D. Kopyciński

    2012-01-01

    Full Text Available In this study presents the analyse of aluminium iron cast structure (as-cast condition which are used in high temperature. While producing the casts of aluminium iron major influence has been preserve the structure of technological process parameters. The addition to Fe-C-Al alloy V, Ti, Cr leads to the improvement of functional and mechanical cast qualities. In this study, a method was investigated to eliminate the presence of undesirable Al4C3 phases in a aluminium cast iron structure and thus improve the production process. V and Ti additions in aluminium cast iron allows to development of FeAl - VC or TiC alloys. In particular, V or Ti contents above 5 wt.% were found to totally eliminate the presence of Al4C3. In addition, preliminary work indicates that the alloy with the FeAl - VC or TiC structure reveals high oxidation resistance. The introduction of 5 wt.% chromium to aluminium cast iron strengthened Al4C3 precipitate. Thus, the resultant alloy can be considered an intermetallic FeAl matrix strengthened by VC and TiC or modified Al4C3 reinforcements.

  5. Aluminium Foams in the Design of Transport Means

    Directory of Open Access Journals (Sweden)

    Krešimir Grilec

    2012-07-01

    Full Text Available The requirements for weight reduction and improvement of performances in the design of transport means are often in contradiction to the requirements for increased safety. One of the possible ways of meeting these requirements is the application of metal foams. Thanks to cellular structure of aluminium foam along with low weight, the capability of noise and vibration damping, they feature also excellent capabilities of absorbing impact energy. Their application in the production of impact-sensitive elements of mobile or stationary transport means has significantly contributed to the reduction of the impact or collision consequences.The focus of this paper is on improving the energy absorption characteristics of aluminium foams considering the significance of their application for the technology of traffic and transport.The paper analyzes the influence of the chemical composition and density on the compression behaviour of aluminium foam. The aluminium foam samples were produced from Alulight precursor. The capability of samples to absorb mechanical energy has been estimated according to the results of compression tests. The tests were performed on a universal test machine. The test results showed that aluminium foams feature good energy absorption and the absorption capability decreases with the foam density. The Alulight AlMgSi 0.6 TiH2 - 0.4 foam can absorb more energy than Alulight AlSi 10 TiH2 – 0.8 foam.

  6. Impact properties of aluminium - glass fiber reinforced plastics sandwich panels

    Directory of Open Access Journals (Sweden)

    Mathivanan Periasamy

    2012-06-01

    Full Text Available Aluminium - glass fiber reinforced plastics (GFRP sandwich panels are hybrid laminates consisting of GFRP bonded with thin aluminum sheets on either side. Such sandwich materials are increasingly used in airplane and automobile structures. Laminates with varying aluminium thickness fractions, fiber volume fractions and orientation in the layers of GFRP were fabricated by hand lay up method and evaluated for their impact performance by conducting drop weight tests under low velocity impacts. The impact energy required for initiating a crack in the outer aluminium layer as well as the energy required for perforation was recorded. The impact load-time history was also recorded to understand the failure behavior. The damage depth and the damage area were measured to evaluate the impact resistance. Optical photography and scanning electron micrographs were taken to visualize the crack and the damage zone. The bidirectional cross-ply hybrid laminate (CPHL has been found to exhibit better impact performance and damage resistance than the unidirectional hybrid laminate (UDHL. Increase in aluminium thickness fraction (Al tf and fiber volume fraction (Vf resulted in an increase in the impact energy required for cracking and perforation. On an overall basis, the sandwich panels exhibited better impact performance than the monolithic aluminium.

  7. Cancer risk among workers of a secondary aluminium smelter.

    Science.gov (United States)

    Maltseva, A; Serra, C; Kogevinas, M

    2016-07-01

    Cancer risk in secondary aluminium production is not well described. Workers in this industry are exposed to potentially carcinogenic agents from secondary smelters that reprocess aluminium scrap. To evaluate cancer risk in workers in a secondary aluminium plant in Spain. Retrospective cohort study of male workers employed at an aluminium secondary smelter (1960-92). Exposure histories and vital status through 2011 were obtained through personal interviews and hospital records, respectively. Standardized mortality (SMRs) and incidence ratios (SIRs) were calculated. The study group consisted of 98 workers. We found increased incidence and mortality from bladder cancer [SIR = 2.85, 95% confidence interval (CI) 1.23-5.62; SMR = 5.90, 95% CI 1.58-15.11]. Increased incidence was also observed for prostate cancer and all other cancers but neither were statistically significant. No increased risk was observed for lung cancer. Results of this study suggest that work at secondary aluminium smelters is associated with bladder cancer risk. Identification of occupational carcinogens in this industry is needed. © The Author 2016. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Thermo-chemical properties and electrical resistivity of Zr-based arsenide chalcogenides

    Directory of Open Access Journals (Sweden)

    A. Schlechte, R. Niewa, M. Schmidt, G. Auffermann, Yu. Prots, W. Schnelle, D. Gnida, T. Cichorek, F. Steglich and R. Kniep

    2007-01-01

    Full Text Available Ternary phases in the systems Zr–As–Se and Zr–As–Te were studied using single crystals of ZrAs1.40(1Se0.50(1 and ZrAs1.60(2Te0.40(1 (PbFCl-type of structure, space group P4/nmm as well as ZrAs0.70(1Se1.30(1 and ZrAs0.75(1Te1.25(1 (NbPS-type of structure, space group Immm. The characterization covers chemical compositions, crystal structures, homogeneity ranges and electrical resistivities. At 1223 K, the Te-containing phases can be described with the general formula ZrAsxTe2−x, with 1.53(1≤x≤1.65(1 (As-rich and 0.58(1≤x≤0.75(1 (Te-rich. Both phases are located directly on the tie-line between ZrAs2 and ZrTe2, with no indication for any deviation. Similar is true for the Se-rich phase ZrAsxSe2−x with 0.70(1≤x≤0.75(1. However, the compositional range of the respective As-rich phase ZrAsx−ySe2−x (0.03(1≤y≤0.10(1; 1.42(1≤x≤1.70(1 is not located on the tie-line ZrAs2–ZrSe2, and exhibits a triangular region of existence with intrinsic deviation of the composition towards lower non-metal contents. Except for ZrAs0.75Se1.25, from the homogeneity range of the Se-rich phase, all compounds under investigation show metallic characteristics of electrical resistivity at temperatures >20 K. Related uranium and thorium arsenide selenides display a typical magnetic field-independent rise of the resistivity towards lower temperatures, which has been explained by a non-magnetic Kondo effect. However, a similar observation has been made for ZrAs1.40Se0.50, which, among the Zr-based arsenide chalcogenides, is the only system with a large concentration of intrinsic defects in the anionic substructure.

  9. Determination of aluminium in groundwater samples by GF-AAS, ICP-AES, ICP-MS and modelling of inorganic aluminium complexes.

    Science.gov (United States)

    Frankowski, Marcin; Zioła-Frankowska, Anetta; Kurzyca, Iwona; Novotný, Karel; Vaculovič, Tomas; Kanický, Viktor; Siepak, Marcin; Siepak, Jerzy

    2011-11-01

    The paper presents the results of aluminium determinations in ground water samples of the Miocene aquifer from the area of the city of Poznań (Poland). The determined aluminium content amounted from aluminium determinations were performed using three analytical techniques: graphite furnace atomic absorption spectrometry (GF-AAS), inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). The results of aluminium determinations in groundwater samples for particular analytical techniques were compared. The results were used to identify the ascent of ground water from the Mesozoic aquifer to the Miocene aquifer in the area of the fault graben. Using the Mineql+ program, the modelling of the occurrence of aluminium and the following aluminium complexes: hydroxy, with fluorides and sulphates was performed. The paper presents the results of aluminium determinations in ground water using different analytical techniques as well as the chemical modelling in the Mineql+ program, which was performed for the first time and which enabled the identification of aluminium complexes in the investigated samples. The study confirms the occurrence of aluminium hydroxy complexes and aluminium fluoride complexes in the analysed groundwater samples. Despite the dominance of sulphates and organic matter in the sample, major participation of the complexes with these ligands was not stated based on the modelling.

  10. IEC 61267: Feasibility of type 1100 aluminium and a copper/aluminium combination for RQA beam qualities.

    Science.gov (United States)

    Leong, David L; Rainford, Louise; Zhao, Wei; Brennan, Patrick C

    2016-01-01

    In the course of performance acceptance testing, benchmarking or quality control of X-ray imaging systems, it is sometimes necessary to harden the X-ray beam spectrum. IEC 61267 specifies materials and methods to accomplish beam hardening and, unfortunately, requires the use of 99.9% pure aluminium (Alloy 1190) for the RQA beam quality, which is expensive and difficult to obtain. Less expensive and more readily available filters, such as Alloy 1100 (99.0% pure) aluminium and copper/aluminium combinations, have been used clinically to produce RQA series without rigorous scientific investigation to support their use. In this paper, simulation and experimental methods are developed to determine the differences in beam quality using Alloy 1190 and Alloy 1100. Additional simulation investigated copper/aluminium combinations to produce RQA5 and outputs from this simulation are verified with laboratory tests using different filter samples. The results of the study demonstrate that although Alloy 1100 produces a harder beam spectrum compared to Alloy 1190, it is a reasonable substitute. A combination filter of 0.5 mm copper and 2 mm aluminium produced a spectrum closer to that of Alloy 1190 than Alloy 1100 with the added benefits of lower exposures and lower batch variability. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  11. Fire design of aluminium structures according to Eurocode 9; Part 1-2

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.

    2007-01-01

    There is a tendency to use aluminium as structural material in heavily loaded structures. In a number of these structures, the resistance to fire should be considered in the structural design. Because of the low melting temperature of aluminium, aluminium structures are sensitive to fire and extra

  12. Light-weight aluminium bridges and bridge decks. An overview of recent applications

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Kluyver, D. de

    2008-01-01

    The last decades have shown a large increase in the application of aluminium alloys for light-weight bridges. For bridge construction, aluminium alloys have some specific advantages, but also some points of attention. This paper deals with some recent projects of aluminium bridges, and for these

  13. Structural perturbation of diphtheria toxoid upon adsorption to aluminium hydroxide adjuvant

    NARCIS (Netherlands)

    Regnier, M.; Metz, B.; Tilstra, W.; Hendriksen, C.; Jiskoot, W.; Norde, W.; Kersten, G.

    2012-01-01

    Aluminium-containing adjuvants are often used to enhance the potency of vaccines. In the present work we studied whether adsorption of diphtheria toxoid to colloidal aluminium hydroxide induces conformational changes of the antigen. Diphtheria toxoid has a high affinity for the aluminium hydroxide

  14. PEMBINAAN PENGERAJIN BOKOR ALUMINIUM DI DESA MENYALI

    Directory of Open Access Journals (Sweden)

    I NYOMAN GDE ANTARA, dkk.

    2014-04-01

    Full Text Available Alluminium bowl craft industrial center is located in Menyali village Sawan district Buleleng regency of Bali province. In this business development, they faced some problems such as increasingly expensive alluminium plate raw materials, decreasing selling product prices due to competition among craftsmen, difficulty in extending the marketing, lack of capital, lack of knowledge in business management, and lack of technical capacity and production innovation. Currently the organization has been formed aluminum bowl craftsmen groups, they are “Sumber Urip” and “Sumur Jaya”. This organization is still limited to tradisional associations such as a community organization, has not led to organize in a micro-enterprise or cooperation. Their organization management should not be arranged. Therefore, they need helps from the government and other institutions to build this bowl craftsmen in developing their businesses through a group of micro-enterprises or cooperations. Wishly, with formal business entity that would facilitate access to a variety of coaching and help governments andother institutions. From the SWOT analysis, it is found some problems and solutions that should be done. Alluminium bowl craftsmen groups, named “Sumber Urip” and “Sumur Jaya” is not in the form of business entity or cooperation yet, so that the results of coaching have agreed to form a cooperation. Venture capital assistance for the development and production are still needed and to be an absolute given, but a way to market more absolute yield is given, through participation in various events exhibition to introduce the product is expected to expandits market share up to overseas or exports. In the production process it has been introduced that is appropriate technology for instant a rolling tool to make a wiring groove on the outside of the bowl, so that it will simplify and speed up the process, especially by aged mothers.Keywords: aluminium bowl, Menyali

  15. Behaviour of painted aluminium in Ibero-American atmosphere

    International Nuclear Information System (INIS)

    Morcillo, M.; Simancas, J.; Corvo, F.; Rosales, B.; Fragata, F.; Pena, J.; Sanchez, M.; Flores, S.; Almeida, E.; Rivero, S.; Rincon, O. T. de

    2003-01-01

    Aluminium generally presents good corrosion resistance to the atmosphere. However, unprotected aluminium and aluminium alloys weather outdoors to an ugly grey colour, which deepens to black in industrial atmospheres, and undergo superficial pitting in marine atmospheres, etc. Finishing technologies are applied for their protection and decoration in a wide range of applications. These technologies basically consist of two protection processes: anodizing and painting: the latter going from conventional solvent base paints to modern water-born, high solids and powder coatings. This paper considers the weathering performance of three paint systems: alkyl, polyurethane and polyester, after more than three years of exposure in a wide spectra of Ibero-American atmospheric conditions. The information reported includes resistance to undercutting corrosion at the scribe, filiform corrosion, fungal attack and change in the physico-chemical properties of the paint surface (loss of gloss, colour changes, chalking, etc.). (Author) 9 refs

  16. Application of Anodization Process for Cast Aluminium Surface Properties Enhancement

    Directory of Open Access Journals (Sweden)

    Włodarczyk-Fligier A.

    2016-09-01

    Full Text Available An huge interest is observed in last years in metal matrix composite, mostly light metal based, which have found their applications in many industry branches, among others in the aircraft industry, automotive-, and armaments ones, as well as in electrical engineering and electronics, where one of the most important issue is related to the corrosion resistance, especially on the surface layer of the used aluminium alloys. This elaboration presents the influence of ceramic phase on the corrosion resistance, quality of the surface layer its thickness and structure of an anodic layer formed on aluminium alloys. As test materials it was applied the aluminium alloys Al-Si-Cu and Al-Cu-Mg, for which heat treatment processes and corrosion tests were carried out. It was presented herein grindability test results and metallographic examination, as well. Hardness of the treated alloys with those ones subjected to corrosion process were compared.

  17. Optically Designed Anodised Aluminium Surfaces: Microstructural and Electrochemical Aspects

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy

    was studied in-situ in a transmission electron microscope and also ex-situ using grazing incidence X-ray diffraction. The Al-Metal oxide surface composites based on TiO2, Y2O3, and CeO2 prepared by friction stir processing were employed to generate light scattering anodised surfaces by embedding oxide...... industry. Conventional colouring techniques applied to anodised aluminium surfaces cannot generate glossy white appearing surfaces due to the fundamental differences in the interaction with visible light that is required. Surfaces appearing as perfect white are due to the scattering of visible light......This thesis presents the research work aimed at generating anodised aluminium surfaces with bright, white, and glossy decorative appearance. The aluminium surface finishing industry has been on the lookout for such surfaces due to their potential applications in aerospace, architecture, and design...

  18. Comparative performance of aluminium copper and iron solar stills

    International Nuclear Information System (INIS)

    Dioha, I.J.; Nwagbo, E.E.; Gulma, N.A.

    1990-12-01

    Three different metal sheets have been used in the fabrication of three different single sloping solar stills of the same surface geometry. The metals were galvanized iron, aluminium and copper. This paper presents the performance of the different stills operating under the same environmental conditions. The observed distillate yields was greatest for copper, then aluminium and lastly, iron still. The differences in the yields is attributed to the differences in the thermal conductivities of the metals. The equivalent local costs for the fabrication of the copper, aluminium and iron stills are respectively $160, $95 and $60. Taking the long run costs into consideration, the copper still is preferred because of its availability, durability, weldability and relatively higher conductivity of 380Wm -1 K -1 value. (author). 9 refs, 2 figs, 2 tabs

  19. Quantitative electron probe microanalysis of borides in aluminium

    International Nuclear Information System (INIS)

    Karduck, P.; Schuerhoff, H.J.; Burchard, W.G.

    1983-01-01

    A procedure for the quantitative analysis of borides in aluminium was introduced. For this purpose the optimal apparative boundary conditions for the EPMA of boron were worked out. With these conditions a satisfactory peak to background ratio of 57 could be achieved for B-Kα-radiation. By application of this method the following conclusion should be drawn concerning the kind of nuclei during grain refinement of aluminium with titanium and boron: For grain refinement of aluminium with titanium and boron in the hypoperitectic region of the binary system Al-Ti TiB 2 -particles in clusters provide the high efficiency of refinement. This entails that the TiB 2 -particles already present in the master alloy remain inert in the melt. Hence, the good efficiency of refinement in this region cannot be attributed to the presence of particles like Al 3 Ti, AlB 2 or (Al, Ti) B 2 . (Author)

  20. Aluminium supplier selection for the automotive parts manufacturer

    Directory of Open Access Journals (Sweden)

    M. Cieśla

    2016-04-01

    Full Text Available This paper presents a methodology for selection of the optimal sources of supply, which is also known as the problem of supplier selection. Theoretical considerations are expanded with research related to aluminium supplier selection for a hypothetical manufacturer of aluminium parts for transportation equipment located in Poland. Evaluation of five suppliers of aluminium from Poland, Germany and Slovenia has been conducted using a weighted scoring method, a strengths and weaknesses method and a graphical method. Choosing the best offer and prioritizing suppliers allows not only the most rational decision in the field of supply logistics to be taken but also the quality of service in the metallurgical industry to be improved.

  1. Simultaneous determination of aluminium and phosphorus by neutron activation analysis

    International Nuclear Information System (INIS)

    Gatschke, W.; Gawlik, D.

    1980-01-01

    With the use of the pneumatic tube system of the BER II reactor, the irradiation position of which is equipped with a movable cadmium shield, the aluminium and phosphorus levels in bone powder and in human bone biopsies were determined. The contribution of aluminium and phosphorus to the 28 Al activity could be separated mathematically after the samples had been irradiated with and without cadmium shielding. The sensitivity and limit of quantitative determination of the analytical procedure were determined using the addition method and the fact that the levels of each element measured was independent of the amount of the other element was proved. (author)

  2. Bioactive type glass-ceramics within incorporated aluminium

    International Nuclear Information System (INIS)

    Volzone, C.; Stabile, F.M.; Ortiga, J.

    2012-01-01

    Bioactive glass-ceramics are used as biomaterials for the reparation of bone tissue. They are prepared, generally, by bioglass of specific composition for each particular use. The aluminium addition in the formulation at very small quantities influences on the structural properties. Two glass-ceramics obtained by P 2 O 5 -Na 2 O-CaO-SiO 2 formulation within aluminium (0.5 % in Al 2 O 3 base) added through a reactive alumina and purified feldspar were analyzed. The results showed structural differences between both glass-ceramics. (author)

  3. Fatigue behaviour of GMAW welded aluminium alloy AA7020

    OpenAIRE

    Bloem, Carlos; Salvador Moya, Mª Dolores; Amigó, Vicente; Vicente-Escuder, Ángel

    2009-01-01

    [EN] The aim of this investigation is to evaluate the influence on fatigue behaviour of the finishing of the bulge in a welded aluminium zinc magnesium alloy AA7020. It was determined that total or partial elimination of the bulge has very little influence on its behaviour, giving a very similar result on both cases, where one is better than the other by only 3%. Bloem, C.; Salvador Moya, MD.; Amigó, V.; Vicente-Escuder, Á. (2009). Fatigue behaviour of GMAW welded aluminium alloy AA7020. W...

  4. Axillary hyperhidrosis treated with alcoholic solution of aluminium chloride hexahydrate.

    Science.gov (United States)

    Scholes, K T; Crow, K D; Ellis, J P; Harman, R R; Saihan, E M

    1978-01-01

    Sixty-five patients with axillary hyperhidrosis took part in a trial of treatment with a solution of 20% aluminium chloride hexahydrate in absolute alcohol, applied topically each night for a week and then whenever the patient thought it necessary. Excellent control of sweating was achieved in 64 patients, and occlusion of the area was found to be unnecessary. No troublesome side effects were reported. The results of this study indicate that 20% aluminium chloride hexahydrate in absolute alcohol is the treatment of first choice for patients with axillary hyperhidrosis. PMID:667571

  5. Transport phenomena of aluminium oxide in metal halide lamps

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, S; Markus, T [Institute for Energy Research, Forschungszentrum Juelich GmbH, D-52425 Juelich (Germany); Niemann, U [Philips GmbH, Research Laboratories, PO Box 500145, Aachen, D-52085 (Germany)], E-mail: s.fischer@fz-juelich.de

    2008-07-21

    A better understanding of the transport phenomena observed in metal halide lamps can be achieved using computer-based model calculations. The chemical transport of aluminium oxide in advanced high-pressure discharge vessels was calculated as a function of temperature and composition of the salt mixture relevant to the lamp. Below 1773 K chemical transport is the prevailing process; above this temperature the vaporization and condensation of the envelope material-aluminium oxide-become more important. The results of the calculations show that the amount of transported alumina increases linearly with the number of iteration cycles and exponentially with the temperature gradient.

  6. Determination of cadmium in aluminium by atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Batistoni, D.A.; Erlijman, L.H.

    1978-12-01

    A direct method for the determination of cadmium in elemental aluminium is described. Metal samples are dissolved in diluted hydrochloric acid and cadmium is determined by atomic absorption spectrometry in an air-acetylene flame. Interference by non-specific absorption observed at the analytical wavelength incorrected for by means of a non-absorbing line emitted by the hollow-cathode lamp. Relatively large amounts of arsenic do not interfere. The minimun determinable concentration of cadmium for this procedure is 2-3 ppm, expressed on aluminium basis. (author) [es

  7. Towards an understanding of the adjuvant action of aluminium

    Science.gov (United States)

    Marrack, Philippa; McKee, Amy S.; Munks, Michael W.

    2011-01-01

    The efficacy of vaccines depends on the presence of an adjuvant in conjunction with the antigen. Of these adjuvants, the ones that contain aluminium, which were first discovered empirically in 1926, are currently the most widely used. However, a detailed understanding of their mechanism of action has only started to be revealed. In this Timeline article, we briefly describe the initial discovery of aluminium adjuvants and discuss historically important advances. We also summarize recent progress in the field and discuss their implications and the remaining questions on how these adjuvants work. PMID:19247370

  8. Effects of aluminium surface morphology and chemical modification on wettability

    DEFF Research Database (Denmark)

    Rahimi, Maral; Fojan, Peter; Gurevich, Leonid

    2014-01-01

    of a monolayer of fluorinated silane, and a combination of those. The effect of these surface modification techniques on roughness and wettability of the aluminium surfaces was elucidated by ellipsometry, contact angle measurements and atomic force microscopy. We demonstrated that by employing different types...... of surface modifications the contact angle of water droplets on aluminium samples can be varied from 12° to more than 120°. A crossover from Cassie–Baxter to Wenzel regime upon changing the surface roughness was also observed....

  9. Accumulation of Aluminium and Physiological Status of Tree Foliage in the Vicinity of a Large Aluminium Smelter

    Directory of Open Access Journals (Sweden)

    E. D. Wannaz

    2012-01-01

    Full Text Available A pollution gradient was observed in tree foliage sampled in the vicinity of a large aluminium production facility in Patagonia (Argentina. Leaves of Eucalyptus rostrata, and Populus hybridus and different needle ages of Pinus spec. were collected and concentrations of aluminium (Al and sulphur (S as well as physiological parameters (chlorophyll and lipid oxidation products were analyzed. Al and S concentrations indicate a steep pollution gradient in the study showing a relationship with the physiological parameters in particular membrane lipid oxidation products. The present study confirms that aluminium smelting results in high Al and sulphur deposition in the study area, and therefore further studies should be carried out taking into account potentially adverse effects of these compounds on human and ecosystem health.

  10. Hair removal using an 810 nm gallium aluminum arsenide semiconductor diode laser: A preliminary study.

    Science.gov (United States)

    Williams, R M; Gladstone, H B; Moy, R L

    1999-12-01

    Laser hair removal is a popular treatment method for removing unwanted hair. Several laser systems are available for laser hair removal. The gallium aluminum arsenide semiconductor diode (GAASD) laser is one of the newer laser modalities to be studied. To evaluate the efficacy of the GAASD laser system in removing unwanted hair. Twenty-six patients with brown or black hair growth were treated with the GAASD laser at fluences of 20-80 J/cm2. Hair regrowth was measured 4 weeks after the first treatment, 4 weeks after the second treatment, 4 weeks after the third treatment, and 4 weeks, 8 weeks, and 8 months after the fourth treatment. GAASD laser treatment resulted in hair growth delay in all treated regions. Repeated laser treatments did not produce an increased number of vellus hairs. The percentage of hair reduction fluctuated between 5% and 13% with the second or third treatment averaging the highest percent reduction. In all cases, the percentage of hair reduction of the treatment sites evaluated at 8 months after the fourth treatment was less than both the second and third treatments (highest average percent reduction) and the fourth (last) treatment.

  11. Radiation effects in silicon and gallium arsenide solar cells using isotropic and normally incident radiation

    Science.gov (United States)

    Anspaugh, B. E.; Downing, R. G.

    1984-01-01

    Several types of silicon and gallium arsenide solar cells were irradiated with protons with energies between 50 keV and 10 MeV at both normal and isotropic incidence. Damage coefficients for maximum power relative to 10 MeV were derived for these cells for both cases of omni-directional and normal incidence. The damage coefficients for the silicon cells were found to be somewhat lower than those quoted in the Solar Cell Radiation Handbook. These values were used to compute omni-directional damage coefficients suitable for solar cells protected by coverglasses of practical thickness, which in turn were used to compute solar cell degradation in two proton-dominated orbits. In spite of the difference in the low energy proton damage coefficients, the difference between the handbook prediction and the prediction using the newly derived values was negligible. Damage coefficients for GaAs solar cells for short circuit current, open circuit voltage, and maximum power were also computed relative to 10 MeV protons. They were used to predict cell degradation in the same two orbits and in a 5600 nmi orbit. Results show the performance of the GaAs solar cells in these orbits to be superior to that of the Si cells.

  12. Irradiation effects of swift heavy ions on gallium arsenide, silicon and silicon diodes

    International Nuclear Information System (INIS)

    Bhoraskar, V.N.

    2001-01-01

    The irradiation effects of high energy lithium, boron, oxygen and silicon ions on crystalline silicon, gallium arsenide, porous silicon and silicon diodes were investigated. The ion energy and fluence were varied over the ranges 30 to 100 MeV and 10 11 to 10 14 ions/cm 2 respectively. Semiconductor samples were characterized with the x-ray fluorescence, photoluminescence, thermally stimulated exo-electron emission and optical reflectivity techniques. The life-time of minority carriers in crystalline silicon was measured with a pulsed electron beam and the lithium depth distribution in GaAs was measured with the neutron depth profiling technique. The diodes were characterized through electrical measurements. The results of optical reflectivity, life-time of minority carriers and photoluminescence show that swift heavy ions induce defects in the surface region of crystalline silicon. In the ion-irradiated GaAs, migration of silicon, oxygen and lithium atoms from the buried region towards the surface was observed, with orders of magnitude enhancement in the diffusion coefficients. Enhancement in the photoluminescence intensity was observed in the GaAs and porous silicon samples that, were irradiated with silicon ions. The trade-off between the turn-off time and the voltage, drop in diodes irradiated with different swift heavy ions was also studied. (author)

  13. Measurement of arsenic and gallium content of gallium arsenide semiconductor waste streams by ICP-MS.

    Science.gov (United States)

    Torrance, Keith W; Keenan, Helen E; Hursthouse, Andrew S; Stirling, David

    2010-01-01

    The chemistry of semiconductor wafer processing liquid waste, contaminated by heavy metals, was investigated to determine arsenic content. Arsenic and gallium concentrations were determined for waste slurries collected from gallium arsenide (GaAs) wafer processing at three industrial sources and compared to slurries prepared under laboratory conditions. The arsenic and gallium content of waste slurries was analyzed using inductively coupled plasma mass-spectrometry (ICP-MS) and it is reported that the arsenic content of the waste streams was related to the wafer thinning process, with slurries from wafer polishing having the highest dissolved arsenic content at over 1,900 mgL(-1). Lapping slurries had much lower dissolved arsenic (manufacturing process, with limited recycling. Although gallium can be economically recovered from waste slurries, there is little incentive to recover arsenic, which is mostly landfilled. Options for treating GaAs processing waste streams are reviewed and some recommendations made for handling the waste. Therefore, although the quantities of hazardous waste generated are miniscule in comparison to other industries, sustainable manufacturing practices are needed to minimize the environmental impact of GaAs semiconductor device fabrication.

  14. Seeded growth of boron arsenide single crystals with high thermal conductivity

    Science.gov (United States)

    Tian, Fei; Song, Bai; Lv, Bing; Sun, Jingying; Huyan, Shuyuan; Wu, Qi; Mao, Jun; Ni, Yizhou; Ding, Zhiwei; Huberman, Samuel; Liu, Te-Huan; Chen, Gang; Chen, Shuo; Chu, Ching-Wu; Ren, Zhifeng

    2018-01-01

    Materials with high thermal conductivities are crucial to effectively cooling high-power-density electronic and optoelectronic devices. Recently, zinc-blende boron arsenide (BAs) has been predicted to have a very high thermal conductivity of over 2000 W m-1 K-1 at room temperature by first-principles calculations, rendering it a close competitor for diamond which holds the highest thermal conductivity among bulk materials. Experimental demonstration, however, has proved extremely challenging, especially in the preparation of large high quality single crystals. Although BAs crystals have been previously grown by chemical vapor transport (CVT), the growth process relies on spontaneous nucleation and results in small crystals with multiple grains and various defects. Here, we report a controllable CVT synthesis of large single BAs crystals (400-600 μm) by using carefully selected tiny BAs single crystals as seeds. We have obtained BAs single crystals with a thermal conductivity of 351 ± 21 W m-1 K-1 at room temperature, which is almost twice as conductive as previously reported BAs crystals. Further improvement along this direction is very likely.

  15. Arsenic moiety in gallium arsenide is responsible for neuronal apoptosis and behavioral alterations in rats

    International Nuclear Information System (INIS)

    Flora, Swaran J.S.; Bhatt, Kapil; Mehta, Ashish

    2009-01-01

    Gallium arsenide (GaAs), an intermetallic semiconductor finds widespread applications in high frequency microwave and millimeter wave, and ultra fast supercomputers. Extensive use of GaAs has led to increased exposure to humans working in semiconductor industry. GaAs has the ability to dissociate into its constitutive moieties at physiological pH and might be responsible for the oxidative stress. The present study was aimed at evaluating, the principle moiety (Ga or As) in GaAs to cause neurological dysfunction based on its ability to cause apoptosis, in vivo and in vitro and if this neuronal dysfunction translated to neurobehavioral changes in chronically exposed rats. Result indicated that arsenic moiety in GaAs was mainly responsible for causing oxidative stress via increased reactive oxygen species (ROS) and nitric oxide (NO) generation, both in vitro and in vivo. Increased ROS further caused apoptosis via mitochondrial driven pathway. Effects of oxidative stress were also confirmed based on alterations in antioxidant enzymes, GPx, GST and SOD in rat brain. We noted that ROS induced oxidative stress caused changes in the brain neurotransmitter levels, Acetylcholinesterase and nitric oxide synthase, leading to loss of memory and learning in rats. The study demonstrates for the first time that the slow release of arsenic moiety from GaAs is mainly responsible for oxidative stress induced apoptosis in neuronal cells causing behavioral changes.

  16. Forward-biased current annealing of radiation degraded indium phosphide and gallium arsenide solar cells

    Science.gov (United States)

    Michael, Sherif; Cypranowski, Corinne; Anspaugh, Bruce

    1990-01-01

    The preliminary results of a novel approach to low-temperature annealing of previously irradiated indium phosphide and gallium arsenide solar cells are reported. The technique is based on forward-biased current annealing. The two types of III-V solar cells were irradiated with 1-MeV electrons to a fluence level of (1-10) x 10 to the 14th electrons/sq cm. Several annealing attempts were made, varying all conditions. Optimum annealing was achieved when cells were injected with minority currents at a constant 90 C. The current density for each type of cell was also determined. Significant recovery of degraded parameters was achieved in both cases. However, the InP cell recovery notably exceeded the recovery in GaAs cells. The recovery is thought to be caused by current-stimulated reordering of the radiator-induced displacement damage. Both types of cell were then subjected to several cycles of irradiation and annealing. The results were also very promising. The significant recovery of degraded cell parameters at low temperature might play a major role in considerably extending the end of life of future spacecraft.

  17. Study of the Hall effect in gallium and indium arsenides in solid and liquid phases

    International Nuclear Information System (INIS)

    Glazov, V.M.; Kol'tsov, V.B.; Sulejmanov, I.R.

    1985-01-01

    Hall effect in gallium and indium arsenides in solid and liquid state is investigated within the framework of a united experiment for the first time. As a result the Hall constant change in the course of these compounds melting is determined experimentally, and on the basis of data obtained and using well-known hopping electric conductivity values, changes of charge carrier density and mobility are estimated. The observed differences in the jumps of pointed characteristics in the course of melting of GaAs compounds on the one hand and InAs - on the other are explained by behaviour peculiarities of the latter in a solid phase dose to the melting temperature. Data on Hall effect in GaAs and InAs melts is abtaned for the first time. Thermal width values of forbidden zone of A 3 As compound calculated on the basis of Hall measurements, conform well with assessment results on the basis of data on electric conductivity

  18. Ab-initio Electronic, Transport and Related Properties of Zinc Blende Boron Arsenide (zb-BAs)

    Science.gov (United States)

    Nwigboji, Ifeanyi H.; Malozovsky, Yuriy; Bagayoko, Diola

    We present results from ab-initio, self-consistent density functional theory (DFT) calculations of electronic, transport, and bulk properties of zinc blende boron arsenide (zb-BAs). We utilized a local density approximation (LDA) potential and the linear combination of atomic orbital (LCAO) formalism. Our computational technique follows the Bagayoko, Zhao, and Williams method, as enhanced by Ekuma and Franklin. Our results include electronic energy bands, densities of states, and effective masses. We explain the agreement between these findings, including the indirect band gap, and available, corresponding, experimental ones. This work confirms the capability of DFT to describe accurately properties of materials, provided the computations adhere to the conditions of validity of DFT [AIP Advances, 4, 127104 (2014)]. Acknowledgments: This work was funded in part by the National Science Foundation (NSF) and the Louisiana Board of Regents, through LASiGMA [Award Nos. EPS- 1003897, NSF (2010-15)-RII-SUBR] and NSF HRD-1002541, the US Department of Energy - National, Nuclear Security Administration (NNSA) (Award No. DE- NA0002630), LaSPACE, and LONI-SUBR.

  19. Transport-reaction model for defect and carrier behavior within displacement cascades in gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Wampler, William R.; Myers, Samuel Maxwell,

    2014-02-01

    A model is presented for recombination of charge carriers at displacement damage in gallium arsenide, which includes clustering of the defects in atomic displacement cascades produced by neutron or ion irradiation. The carrier recombination model is based on an atomistic description of capture and emission of carriers by the defects with time evolution resulting from the migration and reaction of the defects. The physics and equations on which the model is based are presented, along with details of the numerical methods used for their solution. The model uses a continuum description of diffusion, field-drift and reaction of carriers and defects within a representative spherically symmetric cluster. The initial radial defect profiles within the cluster were chosen through pair-correlation-function analysis of the spatial distribution of defects obtained from the binary-collision code MARLOWE, using recoil energies for fission neutrons. Charging of the defects can produce high electric fields within the cluster which may influence transport and reaction of carriers and defects, and which may enhance carrier recombination through band-to-trap tunneling. Properties of the defects are discussed and values for their parameters are given, many of which were obtained from density functional theory. The model provides a basis for predicting the transient response of III-V heterojunction bipolar transistors to pulsed neutron irradiation.

  20. Itinerant Double-Q Spin-Density Wave in Iron Arsenide Superconductors

    Science.gov (United States)

    Osborn, Raymond; Allred, Jared; Chmaissem, Omar; Rosenkranz, Stephan; Brown, Dennis; Taddei, Keith; Krogstad, Matthew; Bugaris, Daniel; Chung, Duck-Young; Claus, Helmut; Lapidus, Saul; Kanatzidis, Mercouri; Kang, Jian; Fernandes, Rafael; Eremin, Ilya

    The recent observation of a tetragonal magnetic (C4) phase in hole-doped iron arsenide superconductors has provided evidence of a magnetic origin for the electronic nematicity in the C2 phase of these compounds. Now, Mössbauer data shows that the new phase also establishes the itinerant character of the antiferromagnetism of these materials and the primary role played by magnetic over orbital degrees of freedom. Neutron diffraction had shown that the magnetic order in the C4 phase was compatible with a double-Q structure arising from a collinear spin-density wave along both the X and Y directions simultaneously. The coherent superposition of the two modulations produces a non-uniform magnetic structure, in which the spin amplitudes vanish on half of the sites and double on the others, a uniquely itinerant effect that is incompatible with local moment magnetism. Mössbauer spectra in the C4 phase confirm this double-Q structure, with 50% of the spectral weight in a zero-moment peak and 50% with double the magnetic splitting seen in the C2 phase. Supported by the US DOE Office of Science, Materials and Engineering Division.

  1. Arsenic moiety in gallium arsenide is responsible for neuronal apoptosis and behavioral alterations in rats.

    Science.gov (United States)

    Flora, Swaran J S; Bhatt, Kapil; Mehta, Ashish

    2009-10-15

    Gallium arsenide (GaAs), an intermetallic semiconductor finds widespread applications in high frequency microwave and millimeter wave, and ultra fast supercomputers. Extensive use of GaAs has led to increased exposure to humans working in semiconductor industry. GaAs has the ability to dissociate into its constitutive moieties at physiological pH and might be responsible for the oxidative stress. The present study was aimed at evaluating, the principle moiety (Ga or As) in GaAs to cause neurological dysfunction based on its ability to cause apoptosis, in vivo and in vitro and if this neuronal dysfunction translated to neurobehavioral changes in chronically exposed rats. Result indicated that arsenic moiety in GaAs was mainly responsible for causing oxidative stress via increased reactive oxygen species (ROS) and nitric oxide (NO) generation, both in vitro and in vivo. Increased ROS further caused apoptosis via mitochondrial driven pathway. Effects of oxidative stress were also confirmed based on alterations in antioxidant enzymes, GPx, GST and SOD in rat brain. We noted that ROS induced oxidative stress caused changes in the brain neurotransmitter levels, Acetylcholinesterase and nitric oxide synthase, leading to loss of memory and learning in rats. The study demonstrates for the first time that the slow release of arsenic moiety from GaAs is mainly responsible for oxidative stress induced apoptosis in neuronal cells causing behavioral changes.

  2. Dynamics and control of gold-encapped gallium arsenide nanowires imaged by 4D electron microscopy.

    Science.gov (United States)

    Chen, Bin; Fu, Xuewen; Tang, Jau; Lysevych, Mykhaylo; Tan, Hark Hoe; Jagadish, Chennupati; Zewail, Ahmed H

    2017-12-05

    Eutectic-related reaction is a special chemical/physical reaction involving multiple phases, solid and liquid. Visualization of a phase reaction of composite nanomaterials with high spatial and temporal resolution provides a key understanding of alloy growth with important industrial applications. However, it has been a rather challenging task. Here, we report the direct imaging and control of the phase reaction dynamics of a single, as-grown free-standing gallium arsenide nanowire encapped with a gold nanoparticle, free from environmental confinement or disturbance, using four-dimensional (4D) electron microscopy. The nondestructive preparation of as-grown free-standing nanowires without supporting films allows us to study their anisotropic properties in their native environment with better statistical character. A laser heating pulse initiates the eutectic-related reaction at a temperature much lower than the melting points of the composite materials, followed by a precisely time-delayed electron pulse to visualize the irreversible transient states of nucleation, growth, and solidification of the complex. Combined with theoretical modeling, useful thermodynamic parameters of the newly formed alloy phases and their crystal structures could be determined. This technique of dynamical control aided by 4D imaging of phase reaction processes on the nanometer-ultrafast time scale opens new venues for engineering various reactions in a wide variety of other systems. Copyright © 2017 the Author(s). Published by PNAS.

  3. Structural anomalies in undoped Gallium Arsenide observed in high resolution diffraction imaging with monochromatic synchrotron radiation

    Science.gov (United States)

    Steiner, B.; Kuriyama, M.; Dobbyn, R. C.; Laor, U.; Larson, D.; Brown, M.

    1988-01-01

    Novel, streak-like disruption features restricted to the plane of diffraction have recently been observed in images obtained by synchrotron radiation diffraction from undoped, semi-insulating gallium arsenide crystals. These features were identified as ensembles of very thin platelets or interfaces lying in (110) planes, and a structural model consisting of antiphase domain boundaries was proposed. We report here the other principal features observed in high resolution monochromatic synchrotron radiation diffraction images: (quasi) cellular structure; linear, very low-angle subgrain boundaries in (110) directions, and surface stripes in a (110) direction. In addition, we report systematic differences in the acceptance angle for images involving various diffraction vectors. When these observations are considered together, a unifying picture emerges. The presence of ensembles of thin (110) antiphase platelet regions or boundaries is generally consistent not only with the streak-like diffraction features but with the other features reported here as well. For the formation of such regions we propose two mechanisms, operating in parallel, that appear to be consistent with the various defect features observed by a variety of techniques.

  4. Resonant photo-thermal modification of vertical gallium arsenide nanowires studied using Raman spectroscopy.

    Science.gov (United States)

    Walia, Jaspreet; Boulanger, Jonathan; Dhindsa, Navneet; LaPierre, Ray; Tang, Xiaowu Shirley; Saini, Simarjeet S

    2016-06-17

    Gallium arsenide nanowires have shown considerable promise for use in applications in which the absorption of light is required. When the nanowires are oriented vertically, a considerable amount of light can be absorbed, leading to significant heating effects. Thus, it is important to understand the threshold power densities that vertical GaAs nanowires can support, and how the nanowire morphology is altered under these conditions. Here, resonant photo-thermal modification of vertical GaAs nanowires was studied using both Raman spectroscopy and electron microscopy techniques. Resonant waveguiding, and subsequent absorption of the excited optical mode reduces the irradiance vertical GaAs nanowires can support relative to horizontal ones, by three orders of magnitude before the onset of structural changes occur. A power density of only 20 W mm(-2) was sufficient to induce local heating in the nanowires, resulting in the formation of arsenic species. Upon further increasing the power, a hollow nanowire morphology was realized. These findings are pertinent to all optical applications and spectroscopic measurements involving vertically oriented GaAs nanowires. Understanding the optical absorption limitations, and the effects of exceeding these limitations will help improve the development of all III-V nanowire devices.

  5. Near-infrared photoluminescence biosensing platform with gold nanorods-over-gallium arsenide nanohorn array.

    Science.gov (United States)

    Zhang, Yiming; Jiang, Tao; Tang, Longhua

    2017-11-15

    The near-infrared (NIR) optical detection of biomolecules with high sensitivity and reliability have been expected, however, it is still a challenge. In this work, we present a gold nanorods (AuNRs)-over-gallium arsenide nanohorn-like array (GaAs NHA) system that can be used for the ultrasensitive and specific NIR photoluminescence (PL) detection of DNA and proteins. The fabrication of GaAs NHA involved the technique of colloidal lithography and inductively coupled plasma dry etching, yielding large-area and well-defined nanostructural array, and exhibiting an improved PL emission compared to the planar GaAs substrate. Importantly, we found that the DNA-bridged AuNRs attachment on NHA could further improve the PL intensity from GaAs, and thereby provide the basis for the NIR optical sensing of biological analytes. We demonstrated that DNA and thrombin could be sensitively and specifically detected, with the detection limit of 1 pM for target DNA and 10 pM for thrombin. Such ultrasensitive NIR optical platform can extend to the detection of other biomarkers and is promising for clinical diagnostics. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. The formation of amplitude spectra in X-ray pixel detectors made of gallium arsenide.

    Science.gov (United States)

    Ayzenshtat, Gennadiy; Prokopiev, Dmitriy; Baidali, Sergey; Tolbanov, Oleg; Dorzheeva, Larisa

    2017-02-21

    This study aims to analyse energy spectra formation in semiconductor X-ray pixel detectors using a simple experimental method. The calculations were performed for the pixel detectors made of high-resistivity gallium arsenide compensated by chromium GaAs (Cr). A peculiar feature of these detectors is an extremely short lifetime of the holes. When using ordinary detectors with planar electrodes the spectra with high energy resolution could not be observed. In this study, the shape of amplitude spectra of gamma rays were calculated with energy W0 = 60 and 17 keV. The calculations were performed for the pixel detector of GaAs (Cr) with the thickness of d = 500μm and pixel pitch of 50μm. The mobility of electrons and holes were assumed to be μn = 3000 cm2/Vs, μp = 300 cm2/Vs, and the lifetimes were τn = 20 ns and τp = 1 ns, respectively. It was demonstrated that in the pixel detector, where there was practically no collection of holes and the amplitude spectra occurred with the energy resolution of 3.5 keV. The calculations show that energy spectra of the pixel detectors has a high energy resolution at an appropriate polarity applied bias voltage. The calculation results were conformed by the experimental data.

  7. In vitro toxicity of gallium arsenide in alveolar macrophages evaluated by magnetometry, cytochemistry and morphology.

    Science.gov (United States)

    Okada, M; Karube, H; Niitsuya, M; Aizawa, Y; Okayasu, I; Kotani, M

    1999-12-01

    Gallium arsenide (GaAs), a chemical compound of gallium and arsenic, causes various toxic effects including pulmonary diseases in animals. Since the toxicity is not completely investigated, GaAs has been used in workplaces as the material of various semiconductor products. The present study was conducted to clarify the toxicity of GaAs particles in the alveolar macrophages of hamsters using magnetometry, enzyme release assays and morphological examinations. Alveolar macrophages obtained from hamsters by tracheobronchial lavage and adhered to the disks in the bottom of wells were exposed to ferrosoferric oxide and GaAs particles. Ferrosoferric oxide particles were magnetized externally and the remanent magnetic field was measured. Relaxation, a fast decline of the remanent magnetic fields radiated from the alveolar macrophages, was delayed and decay constants were decreased dose-dependently due to exposure to GaAs. Because the relaxation is thought to be associated with cytoskeleton, the exposure of GaAs may have impaired the motor function of them. Enzyme release assay and morphological findings indicated the damage to the macrophages. Thus the cytotoxicity causes cytostructural changes and cell death. According to DNA electrophoresis and the TUNEL method, necrotic changes occur more frequently than apoptotic changes.

  8. Do oral aluminium phosphate binders cause accumulation of aluminium to toxic levels?

    Directory of Open Access Journals (Sweden)

    Roberts Norman B

    2011-10-01

    Full Text Available Abstract Background Aluminium (Al toxicity was frequent in the 1980s in patients ingesting Al containing phosphate binders (Alucaps whilst having HD using water potentially contaminated with Al. The aim of this study was to determine the risk of Al toxicity in HD patients receiving Alucaps but never exposed to contaminated dialysate water. Methods HD patients only treated with Reverse Osmosis(RO treated dialysis water with either current or past exposure to Alucaps were given standardised DFO tests. Post-DFO serum Al level > 3.0 μmol/L was defined to indicate toxic loads based on previous bone biopsy studies. Results 39 patients (34 anuric were studied. Mean dose of Alucap was 3.5 capsules/d over 23.0 months. Pre-DFO Al levels were > 1.0 μmol/L in only 2 patients and none were > 3.0 μmol/L. No patients had a post DFO Al levels > 3.0 μmol/L. There were no correlations between the serum Al concentrations (pre-, post- or the incremental rise after DFO administration and the total amount of Al ingested. No patients had unexplained EPO resistance or biochemical evidence of adynamic bone. Conclusions Although this is a small study, oral aluminium exposure was considerable. Yet no patients undergoing HD with RO treated water had evidence of Al toxicity despite doses equivalent to 3.5 capsules of Alucap for 2 years. The relationship between the DFO-Al results and the total amount of Al ingested was weak (R2 = 0.07 and not statistically significant. In an era of financial prudence, and in view of the recognised risk of excess calcium loading in dialysis patients, perhaps we should re-evaluate the risk of using Al-based phosphate binders in HD patients who remain uric.

  9. A Numerical Analysis of the Resistance and Stiffness of the Aluminium and Concrete Composite Beam

    Directory of Open Access Journals (Sweden)

    Polus Łukasz

    2015-03-01

    Full Text Available In this paper a numerical analysis of the resistance and stiffness of the aluminium and concrete composite beam is presented. Composite aluminium and concrete structures are quite new and they have not been thoroughly tested. Composite structures have a lot of advantages. The composite aluminium and concrete beam is more corrosion-resistant, fire-resistant and stiff than the aluminium beam. The contemporary idea of sustainable buildings relies on new solutions which are more environmentally friendly. Aluminium is lighter and more resistant to corrosion than steel, which is often used in composite structures.

  10. Studi Perbandingan Keefektifan Penggunaan Poly Aluminium Chloride (PAC) dan Tawas (Alum) Terhadap Turbiditas dan Kadar Logam Aluminium Pada Air Baku Instalasi Pengolahan Air Di PDAM Tirtanadi Hamparan Perak

    OpenAIRE

    Gea, Deswanti Mariana

    2017-01-01

    The comparative effectiveness study of the usage of the poly aluminium chloride (PAC) and alum towards the turbidity and the aluminium levels at the water treatment installation of PDAM Hamparan Perak has been carried out. The concentration of aluminium chloride and alum usage compared in the raw water has initial turbidity 73,3 NTU and aluminium levels of 0,048 mg/l is respectively 19 ppm; 21 ppm and 23 ppm. And being stirred with agiator found in the Jar Test with a 140 rpm rotation spee...

  11. Experimental weathering rates of aluminium silicates

    International Nuclear Information System (INIS)

    Gudbrandsson, Snorri

    2013-01-01

    The chemical weathering of primary rocks and minerals in natural systems has a major impact on soil development and its composition. Chemical weathering is driven to a large extent by mineral dissolution. Through mineral dissolution, elements are released into groundwater and can readily react to precipitate secondary minerals such as clays, zeolites, and carbonates. Carbonates form from divalent cations (e.g. Ca, Fe and Mg) and CO 2 , and kaolin clay and gibbsite formation is attributed to the weathering of aluminium-rich minerals, most notably the feldspars. The CarbFix Project in Hellisheidi (SW-Iceland) aims to use natural weathering processes to form carbonate minerals by the re-injection of CO 2 from a geothermal power plant back into surrounding basaltic rocks. This process is driven by the dissolution of basaltic rocks, rich in divalent cations, which can combine with injected CO 2 to form and precipitate carbonates. This thesis focuses on the dissolution behaviour of Stapafell crystalline basalt, which consists of three major phases (plagioclase, pyroxene, and olivine) and is rich in divalent cations. Steady-state element release rates from crystalline basalt at far-from-equilibrium conditions were measured at pH from 2 to 11 and temperatures from 5 to 75 C in mixed-flow reactors. Steady-state Si and Ca release rates exhibit a U-shaped variation with pH, where rates decrease with increasing pH at acid condition but increase with increasing pH at alkaline conditions. Silicon release rates from crystalline basalt are comparable to Si release rates from basaltic glass of the same chemical composition at low pH and temperatures ≥25 C but slower at alkaline pH and temperatures ≥50 C. In contrast, Mg and Fe release rates decrease continuously with increasing pH at all temperatures. This behaviour is interpreted to stem from the contrasting dissolution behaviours of the three major minerals comprising the basalt: plagioclase, pyroxene, and olivine. Element

  12. Antioxidant Activity of Natural Products against Aluminium Fluoride ...

    African Journals Online (AJOL)

    Evaluation of antioxidant potential of natural products against Aluminium fluoride (AlF4) induced oxidative stress in albino mice were represented in the present study. Gossypin, Quercetin dehydrate, (-)-Epicatechin gallate, Gallic acid and Suramin sulphate (G-protein inhibitor) were evaluated for antioxidant activity by ...

  13. System for processing aluminium dross in a reduced oxygen environment

    Energy Technology Data Exchange (ETDEWEB)

    Rezac, K.-H.

    1987-01-01

    The processing of dross is becoming an increasingly important economic and environmental consideration in the production, recycling and foundry use of aluminium. It is important, therefore, to develop processes and equipment for cooling and processing dross in the most economical way possible combined with maximum environmental protection. This paper describes the equipment used for carrying out such processing and its operation.

  14. Aluminium dissolution for spray pulverization with nitric acid

    International Nuclear Information System (INIS)

    Rodrigo Otero, A.; Rodrigo Vilaseca, F.; Morales Calvo, G.

    1977-01-01

    A comparative study of the nitric acid dissolution of aluminium, by immersion and spray pulverization has been carried out in laboratory scale. As a result, the optimum operation conditions to control reaction in the plant are fixed. Operation costs are also evaluated. (author) [es

  15. Diamond turning and polishing tests on new RSP aluminium alloys

    NARCIS (Netherlands)

    Horst, R. ter; Haan, M. de; Gubbels, G.P.H.; Senden, R.; Venrooy, B.W.H. van; Hoogstrate, A.M.

    2012-01-01

    For years now conventional aluminium 6061 T6 has widely been used for mirrors in astronomical instruments, being diamond turned or since a few years also being optically polished. This allows the development of optical systems that can be tested and operated at any temperature, without being

  16. Microstructure and defect chemistry of yttrium aluminium garnet ceramics

    International Nuclear Information System (INIS)

    Schuh, L.H.

    1989-01-01

    This thesis describes basic aspects concerning the defect chemistry and the microstructure of yttrium aluminium garnet ceramics. The work consists of three parts: a literature study, an experimental part and a section giving computer simulation data of defects. (author). 320 refs.; 68 figs.; 72 schemes; 32 tabs

  17. Superhydrophobic coatings for aluminium surfaces synthesized by chemical etching process

    Directory of Open Access Journals (Sweden)

    Priya Varshney

    2016-10-01

    Full Text Available In this paper, the superhydrophobic coatings on aluminium surfaces were prepared by two-step (chemical etching followed by coating and one-step (chemical etching and coating in a single step processes using potassium hydroxide and lauric acid. Besides, surface immersion time in solutions was varied in both processes. Wettability and surface morphologies of treated aluminium surfaces were characterized using contact angle measurement technique and scanning electron microscopy, respectively. Microstructures are formed on the treated aluminium surfaces which lead to increase in contact angle of the surface (>150°. Also on increasing immersion time, contact angle further increases due to increase in size and depth of microstructures. Additionally, these superhydrophobic coatings show excellent self-cleaning and corrosion-resistant behavior. Water jet impact, floatation on water surface, and low temperature condensation tests assert the excellent water-repellent nature of coatings. Further, coatings are to be found mechanically, thermally, and ultraviolet stable. Along with, these coatings are found to be excellent regeneration ability as verified experimentally. Although aforesaid both processes generate durable and regenerable superhydrophobic aluminium surfaces with excellent self-cleaning, corrosion-resistant, and water-repellent characteristics, but one-step process is proved more efficient and less time consuming than two-step process and promises to produce superhydrophobic coatings for industrial applications.

  18. Optical and morphological investigation of aluminium and nickel ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 38; Issue 2. Optical and morphological investigation of aluminium and nickel oxide composite films deposited by spray pyrolysis method as a basis of solar thermal absorber. A Bagheri Khatibani S M Rozati. Volume 38 Issue 2 April 2015 pp 319-326 ...

  19. Depth profiling of aluminium metal using slow positron beam ...

    African Journals Online (AJOL)

    Slow positron beam Doppler-broadening technique was used to study depth profiling of aluminium metals sample. The variation of the line-shape parameters with incident positron energy was studied. Also, the depth profile of the S parameter was investigated. The positron implantation profile and backscattering fraction for ...

  20. Aluminium structures in building and civil engineering applications

    NARCIS (Netherlands)

    Soetens, F.

    2010-01-01

    Structural applications of aluminium are considered in this paper. Although the discussion is mainly devoted to Europe, the paper also refers, where possible, to developments in other parts of the world. The problems faced by a designer in creating an optimum design are described, followed by a

  1. Effect of strain path on severely deformed aluminium

    Czech Academy of Sciences Publication Activity Database

    Kunčická, L.; Kocich, R.; Král, Petr; Pohludka, M.; Marek, M.

    2016-01-01

    Roč. 180, OCT (2016), s. 280-283 ISSN 0167-577X Institutional support: RVO:68081723 Keywords : Twist channel angular pressing * Aluminium * Texture * Microstructure Electron microscopy * Metal forming and shaping Subject RIV: JG - Metallurgy Impact factor: 2.572, year: 2016

  2. Oxygen–induced barrier height changes in aluminium – amorphous ...

    African Journals Online (AJOL)

    The results show that the application of voltage causes charge exchange between the surface states and the semiconductor leading to a change in the height of the potential barrier for electrons passing from aluminium into the a-Se films. The empirically determined values of barrier height of Al/a-Se diodes with thin and ...

  3. Sensitivity analysis on ultimate strength of aluminium stiffened panels

    DEFF Research Database (Denmark)

    Rigo, P.; Sarghiuta, R.; Estefen, S.

    2003-01-01

    This paper presents the results of an extensive sensitivity analysis carried out by the Committee III.1 "Ultimate Strength" of ISSC?2003 in the framework of a benchmark on the ultimate strength of aluminium stiffened panels. Previously, different benchmarks were presented by ISSC committees on ul...

  4. Natural Aging Behaviour Of AA6111 Aluminium | Quainoo | Ghana ...

    African Journals Online (AJOL)

    In the continuing drive for weight reduction in new automobile designs, the 6000 series aluminium alloys have emerged as the most promising age-hardenable body sheet material in the automotive industry. Currently, one of the body sheet alloys used for its combination of strength and formability in the (T4) temper is ...

  5. Effects of Aluminium in Forest. Results of a pilot experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mulder, J.; Wit, H. de; Nygaard, P.H.

    1996-01-01

    This conference paper deals with an Norwegian pilot project which started in 1995 and finishing early 1999, investigates the solubility and phyto-toxicity of aluminium (Al) in mature forest ecosystems. The project consists of three major parts, including field manipulation study of Norwegian spruce stands, laboratory experiments and modelling Al chemistry in the root zone. 15 refs.

  6. Differential effects of aluminium on the seedling parameters of wheat ...

    African Journals Online (AJOL)

    ... different aluminium (Al) concentrations on the seedling parameters of wheat and the effect of malate and citrate treatments as chelates for reducing the noxious effect of Al in medium culture and seedlings of two wheat cultivars, Darab (Al sensitive) and Maroon (Al tolerant) were grown on hydroponic solution (non modified ...

  7. Pressurized air ionization chamber with aluminium walls for radiometric dosimetry

    International Nuclear Information System (INIS)

    Rodrigues, R.G.S.; Pela, C.A.; Netto, T.G.

    1996-01-01

    A pressurized air ionization chamber with 23 cm 3 and aluminium walls is evaluated concerning its sensitiveness in low exposure rate. Considering conventional ionization chambers, this chamber shows a better performance since the air pressure of 2500 kPa minimizes the energy dependence to less than 5% between 40 and 1.250 keV

  8. Laser alloying of aluminium to improve surface properties - MSSA 2010

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2010-07-01

    Full Text Available Aluminium is vastly used in industry due to its low cost, light weight and excellent workability, but lacks in wear resistance and hardness. Laser alloying is used to improve the surface properties such as hardness by modifying the composition...

  9. Cavitation-aided grain refinement in aluminium alloys

    NARCIS (Netherlands)

    Atamanenko, T.V.

    2010-01-01

    This thesis deals with grain refinement under the influence of ultrasonic-driven cavitation in aluminium casting processes. Three major goals of this research were: (1) to identify the mechanism of the cavitation-aided grain refinement at different stages of solidification; (2) to reveal the

  10. Contribution to comprehensive study of aluminium alloy Aa 5083 ...

    African Journals Online (AJOL)

    Corrosion induced by elemental mercury in aqueous media of industrial Aluminium alloys AA5083 used in heat exchanger industries of natural gas liquefaction has been studied by linear sweep voltammétry on rotating amalgamated disk electrode. Corrosion process depends on: • Chemical processes of amalgamation of ...

  11. Local electrochemical behaviour of 7xxx aluminium alloys

    NARCIS (Netherlands)

    Andreatta, F.

    2004-01-01

    Aluminium alloys of the 7xxx series (Al-Zn-Mg-Cu) are susceptible to localized types of corrosion like pitting, intergranular corrosion and exfoliation corrosion. This represents a limitation for the application of these alloys in the aerospace components because localized corrosion might have a

  12. Hole quality and burr reduction in drilling aluminium sheets

    DEFF Research Database (Denmark)

    Pilny, Lukas; De Chiffre, Leonardo; Piska, Miroslav

    2011-01-01

    Optimization of the metal drilling process requires creation of minimum amount of burrs and uniform appearance of the drilled holes. In this paper, an experimental investigation was performed on 2 mm sheets of wrought aluminium alloy Al99.7Mg0.5Cu-H24, using 1.6 and 2 mm diameter drills. Cutting...

  13. Hole quality and burr reduction in drilling aluminium sheets

    DEFF Research Database (Denmark)

    Pilny, Lukas; De Chiffre, Leonardo; Piska, Miroslav

    2012-01-01

    Optimization of the metal drilling process requires creation of minimum amount of burrs and uniform appearance of the drilled holes. In this paper, an experimental investigation was performed on 2 mm sheets of wrought aluminium alloy Al99.7Mg0.5Cu-H24, using 1.6 and 2 mm diameter drills. Cutting...

  14. Differential effects of aluminium on the seedling parameters of wheat ...

    African Journals Online (AJOL)

    ALADDIN

    2011-04-25

    Apr 25, 2011 ... Key words: Triticum aestivum L., hydroponic, aluminium-tolerant, length of root, regression analysis. ... cat-ions those immediately surrounding the apical root ... A separate model statement is required for linear, quadratic and cubic trends. RESULTS. ANOVA revealed that, for seedling growth parameters.

  15. Combined aluminium sulfate/hydroxide process for fluoride removal ...

    African Journals Online (AJOL)

    Combined aluminium sulfate/hydroxide process for fluoride removal from drinking water. ... The reported removal efficiency of Nalgonda Technique is 70% at alum dose of 150-170 mg alum/mg F. Besides, sludge production is also minimized. Therefore, this process is highly efficient and could be applied in areas where the ...

  16. Aluminium hydride: a reversible material for hydrogen storage.

    Science.gov (United States)

    Zidan, Ragaiy; Garcia-Diaz, Brenda L; Fewox, Christopher S; Stowe, Ashley C; Gray, Joshua R; Harter, Andrew G

    2009-07-07

    Aluminium hydride has been synthesized electrochemically, providing a synthetic route which closes a reversible cycle for regeneration of the material and bypasses expensive thermodynamic costs which have precluded AlH(3) from being considered as a H(2) storage material.

  17. Examples on cold forged aluminium components in automotive industry

    DEFF Research Database (Denmark)

    Bay, Niels; Kolsgaard, A.

    2000-01-01

    The present paper describes the possibilites of applying cold forging for manufacturing of light weight components in aluminium. A short description of the basic cold forming processes forms the basis for describing the great variety in design of cold forged components. Examples are mainly taken ...... from automotive industry but in a few cases also from other industrial sectors to show the possibilities....

  18. Novel package for inhibition of aluminium corrosion in alkaline solutions

    International Nuclear Information System (INIS)

    Abdel-Gaber, A.M.; Khamis, E.; Abo-Eldahab, H.; Adeel, Sh.

    2010-01-01

    Inhibition of aluminium corrosion in 2 M sodium hydroxide solution by a package composed of the cationic surfactant cetyl trimethyl ammonium bromide (CTAB) and lupine seed extract has been investigated employing different electrochemical techniques and chemical gasometry measurements. Potentiodynamic polarization curve measurements showed that lupine seed extract controls both the anodic dissolution of aluminium and the hydrogen gas evolved at the cathodic sites of aluminium surface. Nyquist plots showed two capacitive semicircles in the high and low frequency regions separated by an inductive loop at intermediate frequencies. The inductive loop may be explained by the occurrence of adsorbed intermediates on the surface. A proposed equivalent circuit was used to analyse the impedance spectra for aluminium in NaOH solutions. The corrosion inhibition data have been analysed using different isotherms. The results showed excellent agreement between the kinetic-thermodynamic model and Flory-Huggins isotherm. Gasometry measurements showed that the Inhibitive effect of the surfactant increases at a composition around its critical micelle concentration (cmc). The presence of both the surfactant and lupine seed extract did not indicate synergistic action between them. The mode of adsorption of the surfactant molecules corresponding to their structure is also discussed.

  19. Elaboration in the area of aluminium containing alloys

    International Nuclear Information System (INIS)

    Mirsaidov, U.M.

    2002-01-01

    In the Institute of Chemistry was elaborated the experimental-industrial installation and technology of deep aluminium purification by the methods of zone melting and recrystallization. The developed technology let receive the metal of model A5 N A6 N dependence from number of induction zone passage

  20. Ultraviolet sensing properties of polyvinyl alcohol-coated aluminium ...

    Indian Academy of Sciences (India)

    Electrochemical; aluminium-doped zinc oxide; PVA-coated; UV sensing. 1. Introduction. Metal oxide semiconductors have received considerable attention due to their excellent physical and chemical prop- erties (Johnson et al 2001; Vayssieres et al 2001; Kolmakov and Moskovits 2004). Zinc oxide (ZnO), one of the most.

  1. Cold forming of aluminium - State of the art

    DEFF Research Database (Denmark)

    Bay, Niels

    1997-01-01

    The ongoing development of cold forging technology has been manifested lately by the increasing application of components in cold forged aluminium alloys. Applying precipitation hardening alloys components with great strength/weight ratio can be produced with a strength comparable to that of unal...

  2. Amelioration of behavioural toxicity of aluminium by oligomeric ...

    African Journals Online (AJOL)

    Despite its limited solubility at neutral pH, aluminium is significantly accumulated by the freshwater snail Lymnaea stagnalis, leading to behavioral toxicity. Both organic (humic acid) and non-organic (oligomeric silicic acid) ligands have been shown to reduce Al accumulation probably owing to their binding affinity for Al. This ...

  3. A vector valued Stefan problem from aluminium industry

    NARCIS (Netherlands)

    F.J. Vermolen; C. Vuik

    1998-01-01

    textabstractDissolution of stoichiometric multi-component particles in ternary alloys is an important process occurring during the heat treatment of as-cast aluminium alloys prior to hot-extrusion. A mathematical model is proposed to describe such a process. In this model an equation is given to

  4. Ultraviolet sensing properties of polyvinyl alcohol-coated aluminium ...

    Indian Academy of Sciences (India)

    295–300. c Indian Academy of Sciences. Ultraviolet sensing properties of polyvinyl alcohol-coated aluminium-doped zinc oxide nanorods. KANCHAN SAXENA. ∗. , AMIT KUMAR, NISHANT MALIK, PRAMOD KUMAR and V K JAIN. Amity Institute of Advanced Research and Studies (Materials and Devices), Amity University, ...

  5. Friction factor of CP aluminium and aluminium–zinc alloys

    Indian Academy of Sciences (India)

    zinc alloys using ring compression test at different temperatures from 303 K to 773 K. It is found that CP aluminium exhibits stick- ing whereas Al–Zn alloys do not exhibit sticking at elevated temperatures. Hot working of Al–Zn alloy is easier.

  6. STRUCTURE OF ECAP ALUMINIUM AFTER DIFFERENT NUMBER OF PASSES

    Directory of Open Access Journals (Sweden)

    Lucia Ilucová

    2011-05-01

    Full Text Available The structure of high purity (99.99% aluminium processed by equal channel angular pressing in the as pressed state after different number of passes was examined using various stereological methods. An extreme inhomogeneity and complicated anisotropy was observed along the body of rod-like specimens.

  7. Study of the dielectric parameters of aluminium ore bauxite of ...

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    are also calculated in the present studies. Keywords. Dielectric parameters; aluminium ore; packing density; minability of ore. 1. Introduction. Dielectric properties of solids in the form of powders may be useful in understanding the structural behaviour of particles in an alternating field. These studies may also be used to for-.

  8. Optical and morphological investigation of aluminium and nickel ...

    Indian Academy of Sciences (India)

    spectrophotometry, various physical properties were investigated. Different optical quantities such as optical band gap, refractive index, extinction coefficient, dielectric constants, volume and surface energy loss functions and optical conductivity were determined. Within this paper for different nickel to aluminium ratio (from ...

  9. Impact toughness of laser alloyed aluminium AA1200 alloys

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2013-08-01

    Full Text Available Laser surface alloying of aluminium AA1200 was performed with a 4kW Nd:YAG laser and impact resistance of the alloys was investigated. The alloying powders were a mixture of Ni, Ti and SiC in different proportions. Surfaces reinforced...

  10. Mechanochemical route to the synthesis of nanostructured Aluminium nitride

    Science.gov (United States)

    Rounaghi, S. A.; Eshghi, H.; Scudino, S.; Vyalikh, A.; Vanpoucke, D. E. P.; Gruner, W.; Oswald, S.; Kiani Rashid, A. R.; Samadi Khoshkhoo, M.; Scheler, U.; Eckert, J.

    2016-01-01

    Hexagonal Aluminium nitride (h-AlN) is an important wide-bandgap semiconductor material which is conventionally fabricated by high temperature carbothermal reduction of alumina under toxic ammonia atmosphere. Here we report a simple, low cost and potentially scalable mechanochemical procedure for the green synthesis of nanostructured h-AlN from a powder mixture of Aluminium and melamine precursors. A combination of experimental and theoretical techniques has been employed to provide comprehensive mechanistic insights on the reactivity of melamine, solid state metal-organic interactions and the structural transformation of Al to h-AlN under non-equilibrium ball milling conditions. The results reveal that melamine is adsorbed through the amine groups on the Aluminium surface due to the long-range van der Waals forces. The high energy provided by milling leads to the deammoniation of melamine at the initial stages followed by the polymerization and formation of a carbon nitride network, by the decomposition of the amine groups and, finally, by the subsequent diffusion of nitrogen into the Aluminium structure to form h-AlN. PMID:27650956

  11. Structure analysis of 3104 aluminium alloy applied to deep drawing

    Energy Technology Data Exchange (ETDEWEB)

    Klyszewski, A.; Lech-Grega, M.; Zelechowski, J.; Szymanski, W. [Light Metals Div., Skawina (Poland). Inst. of Non-Ferrous Metals

    2000-07-01

    Optical and electron microscopy observations and X-ray investigations of 3104 aluminium alloy ingots and bands after experimental heat treatment were carried out. The influence of ingots homogenisation temperature and parameters of material heat treatment after hot rolling on structure, texture and earing of band 0.3 mm thick was analysed. (orig.)

  12. Ultraviolet sensing properties of polyvinyl alcohol-coated aluminium ...

    Indian Academy of Sciences (India)

    Undoped and aluminium (Al)-doped zinc oxide (ZnO) nanorods have been synthesized by electrochemical route. The synthesized materials have been characterized by X-ray diffraction, UV–visible spectrometer and scanning electron microscope. The Al-doped ZnO nanorods have been coated with polyvinyl alcohol.

  13. Establishment of integrated information displays in aluminium surfaces using nanomanufacturing

    DEFF Research Database (Denmark)

    Prichystal, Jan; Hansen, Hans Nørgaard; Bladt, Henrik H.

    2006-01-01

    Bang & Olufsen has been working with a method for manufacturing ultra-thin structures in aluminium that can be penetrated by light. This work has resulted in a patent describing how to obtain this effect by material removal in local areas in a solid material. The idea behind an invisible display...

  14. Thin-film cryogenic resistors from aluminium alloys

    Science.gov (United States)

    Tadros, N. N.; Holdeman, L. B.

    The temperature dependence of the resistances of thin films sputtered from three commercially available aluminium alloys (5052, 5086, 5456) has been measured in the temperature range 1.5-4.2 K. The 5052-alloy films had a positive temperature coefficient of resistance (TCR) throughout this temperature range, whereas films of the other two alloys had a negative TCR.

  15. Verification of Some Vegetable Oils as Cutting Fluid for Aluminium

    African Journals Online (AJOL)

    Akorede

    ABSTRACT: Vegetable oils (palm oil, groundnut oil, shear butter oil and cotton seed oil) have been used as lubricants in the turning operation of aluminum under varying spindle speeds, feed rates and depths of cut and the results compared with kerosene (due to the gummy nature of aluminium metal). The parameters ...

  16. Aluminium localization and toxicity symptoms related to root growth ...

    Indian Academy of Sciences (India)

    We correlated root growth inhibition with aluminium (Al3+) localization and toxicity symptoms in rice roots using seedlings of two genotypes (tolerant and sensitive) that were exposed to different AlCl3 concentrations. Al3+ localization was evaluated by hematoxylin in primary roots and by morin in cross-sections of the root ...

  17. Aluminium(III) alkoxides as unique synthons for heterocyclic ...

    Indian Academy of Sciences (India)

    Administrator

    Facile reactivity of aluminium(III) alkoxides with organic protic reagents with alcohol as the only side product provides a convenient method for the synthesis of a variety of products which may not be synthesized by any other route. The possibility of removal of alcohol azeotropically with solvent benzene makes it possible to ...

  18. Pack nitriding of aluminium using cassava waste | Shitta | Journal of ...

    African Journals Online (AJOL)

    Pack Nitriding is a process analogous to pack carbonizing. In this work, cassava leaves were employed as a source of nitrogen. Upon heating, slow decomposition of the compound provides Nitrogen, the Nitrogen was allowed to interact with aluminium metal surfaces, which were packed nitrided at temperature of 350°c.

  19. Verification of Some Vegetable Oils as Cutting Fluid for Aluminium ...

    African Journals Online (AJOL)

    Vegetable oils (palm oil, groundnut oil, shear butter oil and cotton seed oil) have been used as lubricants in the turning operation of aluminum under varying spindle speeds, feed rates and depths of cut and the results compared with kerosene (due to the gummy nature of aluminium metal). The parameters investigated are ...

  20. A multiple buckling curve formulation for design of aluminium alloy ...

    African Journals Online (AJOL)

    The paper refers to the overall stability design of aluminium structural elements. Buckling curves for members subjected to compression and members subjected to bending are dealt with. The formulation is based on probabilistic considerations of two random events, namely the elastic buckling of a perfect member and the ...

  1. Electrochemical Characterisation of Filiform Corrosion on Aluminium Rolled Products

    NARCIS (Netherlands)

    Huisert, M.

    2001-01-01

    When aluminium is protected by an organic coating a special form of corrosion can occur underneath the organic coating; filiform corrosion. This form of corrosion manifests itself as threadlike filaments under the coating, it causes local delamination of the coating and the coating cannot protect

  2. Aluminium, een nieuw probleem voor landbouw en volksgezondheid? : een literatuuronderzoek

    NARCIS (Netherlands)

    Vos, G.

    1985-01-01

    Door middel van literatuuronderzoek zijn gegevens verzameld met betrekking tot het gedrag van aluminium in de bodem, de toxiciteit voor mens, plant en dier, het voorkomen in levensmiddelen en analysemethoden voor de bepaling van dit element. De huidige aluminiumbelasting via het

  3. Microwave assisted hydrolysis of aluminium metal and preparation ...

    Indian Academy of Sciences (India)

    Centre for Materials for Electronics Technology (C-MET), Department of Information Technology, Government of India, Athani PO, Thrissur 680 581, India. MS received 30 June 2009; revised 27 July 2009. Abstract. Phase pure boehmite particles were prepared by microwave assisted hydrolysis of aluminium sheets.

  4. Dissolved aluminium and the silicon cycle in the Arctic Ocean

    NARCIS (Netherlands)

    Middag, R.; de Baar, H. J. W.; Laan, P.; Bakker, K.

    2009-01-01

    Concentrations of dissolved (0.2 mu m filtered) aluminium (Al) have been determined for the first time in the Eurasian part of the Arctic Ocean over the entire water column during expedition ARK XXII/2 aboard R.V. Polarstern (2007). An unprecedented number of 666 samples was analysed for 44 stations

  5. Trap levels in Y-aluminium garnet scintillating crystals

    Czech Academy of Sciences Publication Activity Database

    Vedda, A.; Di Martino, D.; Martini, M.; Mareš, Jiří A.; Mihóková, Eva; Nikl, Martin; Solovieva, Natalia; Blažek, K.; Nejezchleb, K.

    2004-01-01

    Roč. 38, - (2004), s. 673-676 ISSN 1350-4487 Grant - others:NATO SfP (XX) 973510 Institutional research plan: CEZ:AV0Z1010914 Keywords : aluminium garnets * scintillators * cerium * thetmoluminescence Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.664, year: 2004

  6. Corrosion of research reactor aluminium clad spent fuel in water

    International Nuclear Information System (INIS)

    2009-12-01

    A large variety of research reactor spent fuel with different fuel meats, different geometries and different enrichments in 235 U are presently stored underwater in basins located around the world. More than 90% of these fuels are clad in aluminium or aluminium based alloys that are notoriously susceptible to corrosion in water of less than optimum quality. Some fuel is stored in the reactor pools themselves, some in auxiliary pools (or basins) close to the reactor and some stored at away-from-reactor pools. Since the early 1990s, when corrosion induced degradation of the fuel cladding was observed in many of the pools, corrosion of research reactor aluminium clad spent nuclear fuel stored in light water filled basins has become a major concern, and programmes were implemented at the sites to improve fuel storage conditions. The IAEA has since then established a number of programmatic activities to address corrosion of research reactor aluminium clad spent nuclear fuel in water. Of special relevance was the Coordinated Research Project (CRP) on Corrosion of Research Reactor Aluminium Clad Spent Fuel in Water (Phase I) initiated in 1996, whose results were published in IAEA Technical Reports Series No. 418. At the end of this CRP it was considered necessary that a continuation of the CRP should concentrate on fuel storage basins that had demonstrated significant corrosion problems and would therefore provide additional insight into the fundamentals of localized corrosion of aluminium. As a consequence, the IAEA started a new CRP entitled Corrosion of Research Reactor Aluminium Clad Spent Fuel in Water (Phase II), to carry out more comprehensive research in some specific areas of corrosion of aluminium clad spent nuclear fuel in water. In addition to this CRP, one of the activities under IAEA's Technical Cooperation Regional Project for Latin America Management of Spent Fuel from Research Reactors (2001-2006) was corrosion monitoring and surveillance of research

  7. The Hamlet dilemma for aluminium cans in the circular economy: to be or not to be in a closed loop?

    OpenAIRE

    Niero, Monia; Hoffmeyer, Simon B.; Langen, Håkon; Olsen, Stig Irving

    2015-01-01

    In the context of circular economy the focus is not only on recycling from a quantitative point of view, but also on improving the quality of materials. We considered the case of aluminium cans, and quantified the influence of alloying elements on the overall environmental performances of aluminium can recycling. We performed a Life Cycle Assessment (LCA) comparing different sources of aluminium: primary aluminium and mixed scraps, Used Beverage Can (UBC) scrap, mixed aluminium packaging scra...

  8. Adsorption of lithium ion to amorphous hydrous aluminium oxide

    International Nuclear Information System (INIS)

    Wada, Hideo; Kitamura, Takao; Fujii, Ayako; Katoh, Shunsaku

    1982-01-01

    Adsorption process of lithium ion to amorphous hydrous aluminium oxide (a-HAO) was investigated by pH titration method with lithium chloride-lithium hydroxide mixed solution and X-ray diffraction analysis of a-HAO after pH titration. In the pH titration, the addition of hydroxide ion in amount from 0 to 4.0 mmol.g -1 gave no change to the pH of the solution and caused adsorption of lithium ion equivalent in amount to added hydroxide ion. X-ray diffraction analysis showed the formation of lithium hydrogenaluminate LiH (AlO 2 ) 2 .5H 2 O (LHA) in the a-HAO after pH titration. These results showed that adsorption of lithium ion by a-HAO was related to a reaction which consumed hydroxide ion and formed LHA. In order to elucidate detail process of the reaction, changes of pH, aluminium concentration and lithium concentration of the solution, respectively with time, were determined. The pH of the solution decreased in two stages. At the first stage of the pH decrease, the aluminium concentration increased whereas the lithium concentration did not change. At the second stage, the lithium concentration decreased together with the decrease of the aluminium concentration. It was inferred that adsorption of lithium ion proceeded through dissolution of a-HAO and precipitation of LHA. Theoretical adsorption capacity calculated from the above formula for LHA and aluminium content in a-HAO was 4.7 mmol.g -1 and agreed fairly well with observed value 4.0 mmol.g -1 . (author)

  9. High altitude calibration of thirty-three silicon and gallium arsenide solar cells on a sounding rocket

    Science.gov (United States)

    Thomas, N. L.; Sarles, F. W., Jr.

    1976-01-01

    Twenty-nine n/p silicon and four p/n gallium arsenide solar cells were calibrated on board a high-altitude sounding rocket which provided a stable platform outside the earth's atmosphere. Approximately 75 characteristic current-voltage curves were obtained for each of thirty-two of the cells; the calibration accuracy for both current and voltage was 0.1%. For comparison, the short circuit current, open circuit voltage, and maximum power of the solar cells were also measured under solar simulators (air mass = 0) and on the ground (air mass = 1.2).

  10. Initial oxidation of gallium arsenide (001)-β2(2 x 4) surface using density functional theory.

    Science.gov (United States)

    Kim, Dae-Hee; Kim, Dae-Hyun; Kim, Yeong-Cheol

    2014-10-01

    The initial oxidation of a gallium arsenide (001)-β2(2 x 4) surface with an oxygen molecule was investigated using density functional theory. The oxygen molecule was adsorbed on the surface without any energy barrier. The dissociation of the oxygen molecule on the first arsenic layer had two dissociation paths; the inter-dimer and intra-dimer. The inter-dimer dissociation was the dominant dissociation path based on the energy barriers. The two dissociated oxygen atoms preferred breaking the arsenic-gallium back-bond to form arsenic-oxygen-gallium bonds. Our results are in good agreement with literature of the scanning tunneling microscope study.

  11. Coherent detection of THz waves based on THz-induced time-resolved luminescence quenching in bulk gallium arsenide.

    Science.gov (United States)

    Chu, Zheng; Liu, Jinsong; Wang, Kejia

    2012-05-01

    A kind of photoluminescence quenching, in which the time-resolved photoluminescence is modulated by a THz pulse, has been theoretically investigated by performing the ensemble Monte Carlo method in bulk gallium arsenide (GaAs) at room temperature. The quenching ratio could reach up to 50% under a strong THz field (100  kV/cm). The range in which luminescence quenching is linearly proportional to the THz field could be over 60  kV/cm. On the basis of these results, a principle for THz modulation and coherent detection is proposed.

  12. The Influence of the Annealing Regime on the Properties of Terahertz Antennas Based on Low-Temperature-Grown Gallium Arsenide

    Science.gov (United States)

    Nomoev, S. A.; Vasil'evskii, I. S.; Vinichenko, A. N.; Kozlovskii, K. I.; Chistyakov, A. A.; Mishina, E. D.; Khusyainov, D. I.; Buryakov, A. M.

    2018-01-01

    Low-temperature gallium arsenide (LT-GaAs) films were grown by the method of molecularbeam epitaxy (MBE) at a reduced temperature (230°C) on GaAs(100) substrates and subjected to postgrowth annealing in various regimes. Photoconductive antennas (PCAs) with flag geometry formed on the film surface were characterized by terahertz (THz) response power at various bias voltages. The method of THz spectroscopy was used to study the characteristics of PCAs based on LT-GaAs films annealed in various regimes and the optimum interval of postgrowth annealing temperatures (670-720°C) was established.

  13. Gallium arsenide (GaAs) island growth under SiO(2) nanodisks patterned on GaAs substrates.

    Science.gov (United States)

    Tjahjana, Liliana; Wang, Benzhong; Tanoto, Hendrix; Chua, Soo-Jin; Yoon, Soon Fatt

    2010-05-14

    We report a growth phenomenon where uniform gallium arsenide (GaAs) islands were found to grow underneath an ordered array of SiO(2) nanodisks on a GaAs(100) substrate. Each island eventually grows into a pyramidal shape resulting in the toppling of the supported SiO(2) nanodisk. This phenomenon occurred consistently for each nanodisk across a large patterned area of approximately 50 x 50 microm(2) (with nanodisks of 210 nm diameter and 280 nm spacing). The growth mechanism is attributed to a combination of 'catalytic' growth and facet formation.

  14. Size and environment dependence of surface phonon modes of gallium arsenide nanowires as measured by Raman spectroscopy.

    Science.gov (United States)

    Spirkoska, D; Abstreiter, G; Fontcuberta I Morral, A

    2008-10-29

    Gallium arsenide nanowires were synthesized by gallium-assisted molecular beam epitaxy. By varying the growth time, nanowires with diameters ranging from 30 to 160 nm were obtained. Raman spectra of the nanowire ensembles were measured. The small linewidth of the optical phonon modes agree with an excellent crystalline quality. A surface phonon mode was also revealed, as a shoulder at lower frequencies of the longitudinal optical mode. In agreement with the theory, the surface mode shifts to lower wavenumbers when the diameter of the nanowires is decreased or the environment dielectric constant increased.

  15. Corrosion of aluminium in copper-aluminium couples under a marine environment: Influence of polyaniline deposited onto copper

    Energy Technology Data Exchange (ETDEWEB)

    Vera, Rosa, E-mail: rvera@ucv.c [Instituto de Quimica, Facultad de Ciencias, Pontificia Universidad Catolica de Valparaiso, Avda. Brasil 2950, Casilla 4059, Valparaiso (Chile); Verdugo, Patricia [Departamento de Quimica y Bioquimica, Facultad de Ciencias, Universidad de Valparaiso, Av. Gran Bretana 1111, Valparaiso (Chile); Orellana, Marco; Munoz, Eduardo [Instituto de Quimica, Facultad de Ciencias, Pontificia Universidad Catolica de Valparaiso, Avda. Brasil 2950, Casilla 4059, Valparaiso (Chile)

    2010-11-15

    Research highlights: {yields} The presence of Polyaniline in the Al-Cu system produces a decrease in the oxygen reduction reaction. {yields} In the marine enviroment, aluminium in Al-Cu couples, suffers pitting and exfoliation. {yields} The aluminium deterioration increases with chloride and enviromental sulphur dioxide presence, mainly when it is united to bare copper. - Abstract: In this study, we examined how aluminium corrosion in Al-Cu/PANI galvanic couples in a marine environment is influenced by deposition of polyaniline (PANI) on copper. Polarization curves and immersion assays in 0.1 M NaCl were performed. The morphologies of etched Al and corrosion products were observed by SEM, and the Al ions in solution were quantified by atomic absorption spectroscopy. A reduction in aluminium damage due to galvanic corrosion was observed as a result of decreased effective area for the oxygen reduction reaction on Cu/PANI electrode. Furthermore, an electrochemical reduction of PANI from leucoemeraldine to emeraldine base is proposed.

  16. Decreased toxicity of aluminium when the ionic strength increases in water; Blir aluminium mindre toksisk naar ionestyrken i vannet oeker?

    Energy Technology Data Exchange (ETDEWEB)

    Alstad, E.W. [Oslo Univ. (Norway)

    1996-01-01

    The conference paper evaluates the acute mortality of fish caused by the toxicity of aluminium in water. The evaluation is based on the polymerization hypothesis. According to the author, the level of toxicity decreases when the concentration and charge of ions increase. The paper presents the preliminary results from the executed experiment. 2 refs., 2 figs., 1 tab.

  17. Corrosion of aluminium in copper-aluminium couples under a marine environment: Influence of polyaniline deposited onto copper

    International Nuclear Information System (INIS)

    Vera, Rosa; Verdugo, Patricia; Orellana, Marco; Munoz, Eduardo

    2010-01-01

    Research highlights: → The presence of Polyaniline in the Al-Cu system produces a decrease in the oxygen reduction reaction. → In the marine enviroment, aluminium in Al-Cu couples, suffers pitting and exfoliation. → The aluminium deterioration increases with chloride and enviromental sulphur dioxide presence, mainly when it is united to bare copper. - Abstract: In this study, we examined how aluminium corrosion in Al-Cu/PANI galvanic couples in a marine environment is influenced by deposition of polyaniline (PANI) on copper. Polarization curves and immersion assays in 0.1 M NaCl were performed. The morphologies of etched Al and corrosion products were observed by SEM, and the Al ions in solution were quantified by atomic absorption spectroscopy. A reduction in aluminium damage due to galvanic corrosion was observed as a result of decreased effective area for the oxygen reduction reaction on Cu/PANI electrode. Furthermore, an electrochemical reduction of PANI from leucoemeraldine to emeraldine base is proposed.

  18. Energy conversion from aluminium and phosphate rich solution via ZnO activation of aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Slaughter, Gymama, E-mail: gslaught@umbc.edu; Sunday, Joshua; Stevens, Brian

    2015-08-01

    Electrochemical power sources have motivated intense research efforts in the development of alternative ‘green’ power sources for ultra-low powered bioelectronic devices. Biofuel cells employ immobilized enzymes to convert the available chemical energy of organic fuels directly into electricity. However, biofuel cells are limited by short lifetime due to enzyme inactivation and frequent need to incorporate mediators to shuttle electrons to the final electron acceptor. In this context, other electrochemical power sources are necessary in energy conversion and storage device applications. Here we report on the fabrication and characterization of a membrane-free aluminium/phosphate cell based on the activation of aluminium (Al) using ZnO nanocrystal in an Al/phosphate cell as a ‘green’ alternative to the traditional enzymatic biofuel cells. The hybrid cell operates in neutral phosphate buffer solution and physiological saline buffer. The ZnO modifier in the phosphate rich electrolyte activated the pitting of Al resulting in the production of hydrogen, as the reducing agent for the reduction of H{sub 2}PO{sub 4}{sup −} ions to HPO{sub 3}{sup 2−} ions at a formal potential of −0.250 V vs. Ag/AgCl. Specifically, the fabricated cell operating in phosphate buffer and physiological saline buffer exhibit an open-circuit voltage of 0.810 V and 0.751 V and delivered a maximum power density of 0.225 mW cm{sup −2} and 1.77 mW cm{sup −2}, respectively. Our results demonstrate the feasibility of generating electricity by activating Al as anodic material in a hybrid cell supplied with phosphate rich electrolyte. Our approach simplifies the construction and operation of the electrochemical power source as a novel “green” alternative to the current anodic substrates used in enzymatic biofuel cells for low power bioelectronics applications. - Graphical abstract: Display Omitted - Highlights: • ZnO activation of metallic Al for generating electricity for

  19. Investigation on properties of ultrafast switching in a bulk gallium arsenide avalanche semiconductor switch

    International Nuclear Information System (INIS)

    Hu, Long; Su, Jiancang; Ding, Zhenjie; Hao, Qingsong; Yuan, Xuelin

    2014-01-01

    Properties of ultrafast switching in a bulk gallium arsenide (GaAs) avalanche semiconductor switch based on semi-insulating wafer, triggered by an optical pulse, were analyzed using physics-based numerical simulations. It has been demonstrated that when a voltage with amplitude of 5.2 kV is applied, after an exciting optical pulse with energy of 1 μJ arrival, the structure with thickness of 650 μm reaches a high conductivity state within 110 ps. Carriers are created due to photons absorption, and electrons and holes drift to anode and cathode terminals, respectively. Static ionizing domains appear both at anode and cathode terminals, and create impact-generated carriers which contribute to the formation of electron-hole plasma along entire channel. When the electric field in plasma region increases above the critical value (∼4 kV/cm) at which the electrons drift velocity peaks, a domain comes into being. An increase in carrier concentration due to avalanche multiplication in the domains reduces the domain width and results in the formation of an additional domain as soon as the field outside the domains increases above ∼4 kV/cm. The formation and evolution of multiple powerfully avalanching domains observed in the simulations are the physical reasons of ultrafast switching. The switch exhibits delayed breakdown with the characteristics affected by biased electric field, current density, and optical pulse energy. The dependence of threshold energy of the exciting optical pulse on the biased electric field is discussed

  20. Molybdenum disulphide (MoS2) - gallium arsenide (GaAs) heterostructures for solar cell applications

    International Nuclear Information System (INIS)

    Jamieson, I.M.; Jakovidis, G.

    2004-01-01

    Full text: Heterostructures provide a means of absorbing a greater range of the broad solar spectrum in photovoltaic cells compared with single band gap materials. Several layered transition metal dichalcogenides are potential candidates since they have near ideal top layer band gap energy, high absorption coefficients, long minority carrier lifetimes, and large diffusion lengths. One major problem with heterostructures has been the lattice parameter mismatch leading to misfit dislocations. Such defects act as recombination centres that are detrimental to cell performance. Two dimensional layered materials overcome this difficulty because a weak Van der Waals interaction exists at the interface instead of the usual epitaxial growth, with crystallographic texture an important film structural property. If the layered compounds are to be useful as solar cells then they must be grown in a highly textured manner with the c-axis perpendicular to the substrate. Much effort has been devoted to such growth, to date there is no method which does not rely on metal particles or substrates that promote precursor phases to achieve this aim. In this study, thin films of a model material from this class, molybdenum disulphide, MoS 2 , (band gap E g = 1.8 eV), has been deposited by radio frequency magnetron sputtering and pulsed laser deposition techniques on a gallium arsenide substrate (E g =1.4 eV). Thin film structures are characterised mainly by angle dispersive x-ray diffraction, scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. These techniques reveal that there exists a region of parameter space where substantial desired bulk texturing of MoS 2 takes place without the need for metal or precursor phases. It was found that higher substrate temperatures, lower power density and higher sputtering gas pressures favoured the desired texture

  1. Gallium arsenide selectively up-regulates inflammatory cytokine expression at exposure site.

    Science.gov (United States)

    Becker, Stephen M; McCoy, Kathleen L

    2003-12-01

    Gallium arsenide (GaAs), a technologically and economically important semiconductor, is widely utilized in both military and commercial applications. This chemical is a potential health hazard as a carcinogen and immunotoxicant. We previously reported that macrophages at the exposure site exhibit characteristics of activation. In vitro culture of macrophages with GaAs fails to recapitulate the in vivo phenotype, suggesting that complete GaAs-mediated activation in vivo may require other cells or components found in the body's microenvironment. Our present study examined the role of cytokines upon GaAs-mediated macrophage activation. Intraperitoneal administration of GaAs elicited rapid specific recruitment of blood monocytes to the exposure site. This recruitment occurred concomitant with up-regulation of 17 chemokine and inflammatory cytokine mRNAs, while transcripts of three inhibitory cytokines diminished. Administration of latex beads caused less cytokine induction than GaAs, indicating that changes in mRNA levels could not be attributed to phagocytosis. Four representative chemokines and cytokines were selected for further analysis. Increased cytokine mRNA expression was paralleled by similar increases in cytokine protein levels, and secreted protein products were detected in peritoneal fluid. Cytokine protein expression was constrained to myeloid cells, and to a lesser extent to B cells. Alterations in patterns of cytokine gene expression elucidate mechanisms for increased cellular activation and antigen processing, and modulation of the inflammatory response. Our findings indicate that in vivo GaAs exposure alters cytokine gene expression, which may lead to an inflammatory reaction and contribute to pathological tissue damage.

  2. An Indium Gallium Arsenide Visible/SWIR Focal Plane Array for Low Light Level Imaging

    Science.gov (United States)

    Cohen, Marshall J.; Ettenberg, Martin H.; Lange, Michael J.; Olsen, Gregory H.

    1999-01-01

    PIN photodiodes fabricated from indium gallium arsenide lattice-matched to indium phosphide substrates (In(.53)Ga(.47)As/InP) exhibit low reverse saturation current densities (JD 10(exp 6) omega-sq cm) at T=290K. Backside-illuminated, hybrid-integrated InGaAs FPAs are sensitive from 0.9 micrometers to 1.7 micrometers. 290K detectivities, D(*), greater than 10(exp 14) cm-(square root of Hz/W) are demonstrated. This represents the highest room temperature detectivity of any infrared material. The long wavelength cutoff (1.7 micrometers) makes In(.53)Ga(.47)As an idea match to the available airglow that has major peaks at 1.3 micrometers and 1.6 micrometers. The short wavelength 'cut-on' at 0.9 micrometers is due to absorption in the InP substrate. We will report on new InGaAs FPA epitaxial structures and processing techniques. These have resulted in improved performance in the form of a 10 x increase in detectivity and visible response via removal of the InP substrate. The resulting device features visible and SWIR response with greater than 15% quantum efficiency at 0.5 micrometers while maintaining the long wavelength cutoff. Imaging has been demonstrated under overcast starlight/urban glow conditions with cooling provided by a single stage thermoelectric cooler. Details on the material structure and device fabrication, quantitative characterization of spectral response and detectivity, as well as examples of night vision imagery are presented.

  3. Aluminium tolerance in rice is antagonistic with nitrate preference and synergistic with ammonium preference.

    Science.gov (United States)

    Zhao, Xue Qiang; Guo, Shi Wei; Shinmachi, Fumie; Sunairi, Michio; Noguchi, Akira; Hasegawa, Isao; Shen, Ren Fang

    2013-01-01

    Acidic soils are dominated chemically by more ammonium and more available, so more potentially toxic, aluminium compared with neutral to calcareous soils, which are characterized by more nitrate and less available, so less toxic, aluminium. However, it is not known whether aluminium tolerance and nitrogen source preference are linked in plants. This question was investigated by comparing the responses of 30 rice (Oryza sativa) varieties (15 subsp. japonica cultivars and 15 subsp. indica cultivars) to aluminium, various ammonium/nitrate ratios and their combinations under acidic solution conditions. indica rice plants were generally found to be aluminium-sensitive and nitrate-preferring, while japonica cultivars were aluminium-tolerant and relatively ammonium-preferring. Aluminium tolerance of different rice varieties was significantly negatively correlated with their nitrate preference. Furthermore, aluminium enhanced ammonium-fed rice growth but inhibited nitrate-fed rice growth. The results suggest that aluminium tolerance in rice is antagonistic with nitrate preference and synergistic with ammonium preference under acidic solution conditions. A schematic diagram summarizing the interactions of aluminium and nitrogen in soil-plant ecosystems is presented and provides a new basis for the integrated management of acidic soils.

  4. Aluminium content of foods originating from aluminium-containing food additives.

    Science.gov (United States)

    Ogimoto, Mami; Suzuki, Kumi; Haneishi, Nahoko; Kikuchi, Yuu; Takanashi, Mayu; Tomioka, Naoko; Uematsu, Yoko; Monma, Kimio

    2016-09-01

    Aluminium (Al) levels of 90 food samples were investigated. Nineteen samples contained Al levels exceeding the tolerable weekly intake (TWI) for young children [body weight (bw): 16 kg] when consuming two servings/week. These samples were purchased multiple times at specific intervals and were evaluated for Al levels. Al was detected in 27 of the 90 samples at levels ranging from 0.01 (limit of quantitation) to 1.06 mg/g. Of these, the Al intake levels in two samples (cookie and scone mix, 1.3 and 2 mg/kg bw/week, respectively) exceeded the TWI as established by European Food Safety Authority, although the level in the scone mix was equivalent to the provisional TWI (PTWI) as established by Joint Food and Agriculture Organization of the United Nations/World Health Organization Expert Committee on Food Additives. The Al levels markedly decreased in 14 of the 19 samples with initially high Al levels. These results indicated reductions in the Al levels to below the PTWI limits in all but two previously identified food samples.

  5. Method of preparing an Al-Ti-B grain refiner for aluminium-comprising products, and a method of casting aluminium products

    NARCIS (Netherlands)

    Brinkman, H.J.; Duszczyk, J.; Katgerman, L.

    1999-01-01

    The invention relates to a method of preparing an Al-Ti-B grain refiner for cast aluminium-comprising products. According to the invention the preparation is realized by mixing powders selected from the group comprising aluminium, titanium, boron, and alloys and intermetallic compounds thereof,

  6. Clinical evaluation of dentin hypersensitivity treatment with the low intensity Gallium-Aluminum-Arsenide laser - AsGaAl.

    Science.gov (United States)

    Gentile, Luciana Chucre; Greghi, Sebastião Luiz Aguiar

    2004-12-01

    The dentin hypersensitivity is a painful condition rather prevalent in the general population. There are several ways of treatment for such condition, including the low intensity lasers. The proposal of this study was to verify the effectiveness of the Gallium-Aluminum-Arsenide diode laser in the treatment of this painful condition, using a placebo as control. Thirty-two patients were selected, 22 females and 10 males, with ages ranging from 20 to 52 years old. The 32 patients were randomly distributed into two groups, treated and control; the sample consisted of 68 teeth, 35 in the treated group and 33 in the control group. The treated group was exposed to six laser applications with intervals from 48 to 72 hours, and the control group received, as placebo, applications of a curing light. A significant reduction was observed in the pain condition between the initial phase and after six laser applications; however, such reduction could also be observed for the control group exposed to the placebo. Therapy with the low intensity Gallium-Aluminum-Arsenide laser - AsGaAl induces a statistically significant reduction in the painful condition after each application and between the beginning and end of treatment, although there was no statistically significant difference between the treated group (laser) and the control group (placebo) at the end of treatment and after the mediate evaluation results (after 6 weeks), this way impairing the real measurement of laser effectiveness and placebo effect.

  7. Phase diagram of (Li(1-x)Fe(x))OHFeSe: a bridge between iron selenide and arsenide superconductors.

    Science.gov (United States)

    Dong, Xiaoli; Zhou, Huaxue; Yang, Huaixin; Yuan, Jie; Jin, Kui; Zhou, Fang; Yuan, Dongna; Wei, Linlin; Li, Jianqi; Wang, Xinqiang; Zhang, Guangming; Zhao, Zhongxian

    2015-01-14

    Previous experimental results have shown important differences between iron selenide and arsenide superconductors which seem to suggest that the high-temperature superconductivity in these two subgroups of iron-based families may arise from different electronic ground states. Here we report the complete phase diagram of a newly synthesized superconducting (SC) system, (Li1-xFex)OHFeSe, with a structure similar to that of FeAs-based superconductors. In the non-SC samples, an antiferromagnetic (AFM) spin-density-wave (SDW) transition occurs at ∼127 K. This is the first example to demonstrate such an SDW phase in an FeSe-based superconductor system. Transmission electron microscopy shows that a well-known √5×√5 iron vacancy ordered state, resulting in an AFM order at ∼500 K in AyFe2-xSe2 (A = metal ions) superconductor systems, is absent in both non-SC and SC samples, but a unique superstructure with a modulation wave vector q = (1)/2(1,1,0), identical to that seen in the SC phase of KyFe2-xSe2, is dominant in the optimal SC sample (with an SC transition temperature Tc = 40 K). Hence, we conclude that the high-Tc superconductivity in (Li1-xFex)OHFeSe stems from the similarly weak AFM fluctuations as FeAs-based superconductors, suggesting a universal physical picture for both iron selenide and arsenide superconductors.

  8. Characterization of solar cells for space applications. Volume 14: Electrical characteristics of Hughes liquid phase epitaxy gallium arsenide solar cells as a function of intensity, temperature and irradiation

    Science.gov (United States)

    Anspaugh, B. E.; Downing, R. G.; Miyahira, T. F.; Weiss, R. S.

    1981-01-01

    Electrical characteristics of liquid phase epitaxy, P/N gallium aluminum arsenide solar cells are presented in graphical and tabular format as a function of solar illumination intensity and temperature. The solar cells were exposed to 1 MeV electron fluences of, respectively, 0, one hundred trillion, one quadrillion, and ten quadrillion e/sq cm.

  9. Optical parametric generation by a simultaneously Q-switched mode-locked single-oscillator thulium-doped fiber laser in orientation-patterned gallium arsenide.

    Science.gov (United States)

    Donelan, Brenda; Kneis, Christian; Scurria, Giuseppe; Cadier, Benoît; Robin, Thierry; Lallier, Eric; Grisard, Arnaud; Gérard, Bruno; Eichhorn, Marc; Kieleck, Christelle

    2016-11-01

    Optical parametric generation is demonstrated in orientation-patterned gallium arsenide, pumped by a novel single-oscillator simultaneously Q-switched and mode-locked thulium-doped fiber laser, downconverting the pump radiation into the mid-infrared wavelength regime. The maximum output energy reached is greater than 2.0 μJ per pump pulse.

  10. Thermal Effect of Ceramic Nanofiller Aluminium Nitride on Polyethylene Properties

    Directory of Open Access Journals (Sweden)

    Omer Bin Sohail

    2012-01-01

    Full Text Available Ethylene polymerization was done to form polyethylene nano-composite with nanoaluminum nitride using zirconocene catalysts. Results show that the catalytic activity is maximum at a filler loading of 15 mg nanoaluminum nitride. Differential scanning calorimeter (DSC and X-ray diffraction (XRD results show that percentage crystallinity was also marginally higher at this amount of filler. Thermal behavior of polyethylene nanocomposites (0, 15, 30, and 45 mg was studied by DSC and thermal gravimetric analyzer (TGA. Morphology of the component with 15 mg aluminium nitride is more fibrous as compared to 0 mg aluminium nitride and higher filler loading as shown by SEM images. In order to understand combustibility behavior, tests were performed on microcalorimeter. Its results showed decrease in combustibility in polyethylene nanocomposites as the filler loading increases.

  11. Environment pollution with aluminium around a coalburning electric power plant

    International Nuclear Information System (INIS)

    Hermann, J.

    1997-01-01

    The experiments were carried out from November 1991 till November 1993 on the area surrounding an electric power plant within the circle of 20 km diameter and five geographical directions (N, S, SE, E, W). The results presented in this paper have indicated the threats caused by emissions of the power plant ashes and dusts. Mean aluminium content in soil has been multiply surpassed on the area studied. This must have as impact on fauna and flora. The distribution and intensity of pollution is determined first of all by the distance from the emitters and direction of prevailing winds. A part of aluminium contained in water soluble compounds can be distributed on large areas, what adds a lot to the threat to animals. That is why high chimneys do not solve the problem of pollution around big industrial plants. (author)

  12. High-pressure direct synthesis of aluminium nitride

    CERN Document Server

    Bockowski, M; Grzegory, I; Krukowski, S; Wróblewski, M; Porowski, S

    2002-01-01

    We report the results of direct synthesis of aluminium nitride (AlN) under high nitrogen pressure up to 1 GPa and temperatures up to 2000 K. At pressure from 10 to 650 MPa we observe the combustion synthesis of AlN. As the result of the combustion process one can obtain the AlN sintered powder or AlN/Al metal matrix composites. For N sub 2 pressure higher than 650 MPa the crystal growth of AlN from the solution of atomic nitrogen in aluminium is possible. Both needle-like and bulk AlN single crystals, up to 1 cm and 1 mm, respectively, have been obtained.

  13. TORSIONAL DEFORMATION AND FATIGUE BEHAVIOUR OF 6061 ALUMINIUM ALLOY

    Directory of Open Access Journals (Sweden)

    marini marno

    2012-02-01

    Full Text Available Torsional deformation and fatigue behaviour of both solid and thin-walled tubular specimens were made from as-received and heat treated 6061 aluminium alloy were studied. 6061 aluminium alloy have been widely used as a candidate material in automobile, aerospace, aircraft and structural application because of their superior mechanical properties such as high strength to weight ratio, good ductility and others. The differences in cyclic deformation and fatigue behaviours between round and solid specimens where a stress gradient exist, and thin-walled tubular specimens where a uniform stress state is commonly assumed, are also discussed. Von Mises and Tresca criteria has been used to predict the monotonic and cyclic deformation curve and compared to the torsional data obtained from the experiment. The S-N curve was used to present and evaluate the fatigue life of the specimens. Through fractographic analysis, failure criteria of fracture surfaces were observed and discussed. 

  14. Numerical Modelling of Drawbeads for Forming of Aluminium Alloys

    Science.gov (United States)

    Joshi, Y.; Christiansen, P.; Masters, I.; Bay, N.; Dashwood, R.

    2016-08-01

    The drawbeads in stamping tools are usually designed based on experience from the forming of steel. However, aluminium alloys display different forming behaviour to steels, which is not reflected in the drawbead design for tools used for stamping aluminium. This paper presents experimental results from different semi-circular drawbead geometries commonly encountered in automotive dies and compares them to those obtained from Stoughton's analytical drawbead model and the 2D plane strain drawbead model set up using LS-DYNA. The study was conducted on lubricated NG5754 strips. The results presented are in terms of drawbead restraining force versus strip displacement, as a function of drawbead depth. The FE drawbead model agrees well with the experiments whereas the analytical model overpredicted the drawbead forces.

  15. Dynamical properties of aluminium from experimental dispersion relations

    International Nuclear Information System (INIS)

    Salles Filho, J.B.V.; Fulfaro, R.; Vinhas, L.A.

    1987-05-01

    Measurements of phonon dispersion relations of aluminium along the high symmetry directions were performed by coherent inelastic scattering of thermal neutrons technique. All measurements were taken at room temperature using the IPEN triple axis neutorn spectrometer. The results obtained with accuracy are in good agreement with the published data. The dispersion relations were calculated theoretically within the framework of Born-von Karman and Axially Symmetric models, including interactions up to the fifth nearest shell of atoms. The elastic constants were determined using the values of sound propagating velocity obtained directly from the dispersion relations along of high symmetry directions of the crystal. Applying theoretical models the force constants of aluminium were also determined. From these data several physical properties of the metal can be obtained. (Author) [pt

  16. Neutron small angle scattering of irradiated aluminium-silicon alloys

    International Nuclear Information System (INIS)

    Kostorz, G.

    1976-01-01

    Technically pure aluminium and aluminium-silicon alloys (0.43, 0.83 and 1.2% Si, also containing 0.11 to 0.14 at. % Fe) were investigated by slow neutron small angle scattering after irradiation with fast neutrons at low temperatures. Different irradiation levels, ageing at room temperature and at 60/70 0 C had no measurable effect upon small angle scattering cross-sections. From the experimental precision upper limit for the amount of Si involved in clustering after irradiation can be given. The observed small angle scattering shows a strong dependence on scattering angles and is attributed to large precipitates of Al 12 Fe 3 Si. A surface layer on the as-received samples is identified as another source of low-intensity small angle scattering. (orig.) [de

  17. Longitudinal study of workers of an aluminium die casting factory.

    Science.gov (United States)

    Discalzi, G L; Capellaro, F; Baracco, A

    1992-01-01

    We conducted a 5-year longitudinal study on 76 workers of a high and medium aluminium alloy die-casting factory. As in a previous cross-sectional study conducted in 1986 and in accordance with the data in the literature, the 1990 follow-up study showed: a low prevalence of chronic bronchitis (as defined by the ECSC questionnaire on respiratory symptoms); normal mean functional values of FVC, FEV1, FEV1/FVC%. We did not find any significant difference in the levels of lung function over the period of 1986-90. These results show that workers in the secondary aluminium industry are not exposed to a significant risk of chronic pulmonary disease.

  18. Nanosized f.c.c. thallium inclusions in aluminium

    International Nuclear Information System (INIS)

    Johnson, E.; Johansen, A.; Thoft, N.B.; Andersen, H.H.; Sarholt-Kristensen, L.

    1993-01-01

    Ion implantation of pure aluminium with thallium induces the formation of nanosized crystalline inclusions of thallium with a f.c.c. structure. The size of the inclusions depends on the implantation conditions and subsequent annealing treatments and is typically in the range from 1 to 10 nm. The inclusions are aligned topotactically with the aluminium matrix with a cube-cube orientation relationship and they have a truncated octahedral shape bounded by {111} and {001} planes. The lattice parameter of the f.c.c. thallium inclusions is 0.484 ± 0.002 nm, which is slightly but significantly larger than in the high-pressure f.c.c. thallium phase known to be stable above 3.8 GPa. (Author)

  19. Influence of Chemical Composition on Porosity in Aluminium Alloys

    Directory of Open Access Journals (Sweden)

    Kucharčík L.

    2014-06-01

    Full Text Available Porosity is one of the major defects in aluminum castings, which results is a decrease of a mechanical properties. Porosity in aluminum alloys is caused by solidification shrinkage and gas segregation. The final amount of porosity in aluminium castings is mostly influenced by several factors, as amount of hydrogen in molten aluminium alloy, cooling rate, melt temperature, mold material, or solidification interval. This article deals with effect of chemical composition on porosity in Al-Si aluminum alloys. For experiment was used Pure aluminum and four alloys: AlSi6Cu4, AlSi7Mg0, 3, AlSi9Cu1, AlSi10MgCu1.

  20. Persistent Skin Reactions and Aluminium Hypersensitivity Induced by Childhood Vaccines.

    Science.gov (United States)

    Salik, Elaha; Løvik, Ida; Andersen, Klaus E; Bygum, Anette

    2016-11-02

    There is increasing awareness of reactions to vaccination that include persistent skin reactions. We present here a retrospective investigation of long-lasting skin reactions and aluminium hypersensitivity in children, based on medical records and questionnaires sent to the parents. In the 10-year period 2003 to 2013 we identified 47 children with persistent skin reactions caused by childhood vaccinations. Most patients had a typical presentation of persisting pruritic subcutaneous nodules. Five children had a complex diagnostic process involving paediatricians, orthopaedics and plastic surgeons. Two patients had skin biopsies performed from their skin lesions, and 2 patients had the nodules surgically removed. Forty-two children had a patch-test performed with 2% aluminium chloride hexahydrate in petrolatum and 39 of them (92%) had a positive reaction. The persistent skin reactions were treated with potent topical corticosteroids and disappeared slowly. Although we advised families to continue vaccination of their children, one-third of parents omitted or postponed further vaccinations.

  1. Melting and solidification of bismuth inclusions in aluminium

    DEFF Research Database (Denmark)

    Thoft, N.B.; Bohr, J.; Buras, B.

    1995-01-01

    Supercooling of crystalline bismuth inclusions in aluminium crystals has been observed and studied with different techniques: x-ray diffraction, in situ Rutherford backscattering/channelling spectrometry and transmission electron microscopy. The results of the measurements with different experime......Supercooling of crystalline bismuth inclusions in aluminium crystals has been observed and studied with different techniques: x-ray diffraction, in situ Rutherford backscattering/channelling spectrometry and transmission electron microscopy. The results of the measurements with different...... experimental methods (and on different samples) agree remarkably well. The inclusions melt at temperatures at or below the bismuth bulk melting point, and the solid/liquid phase transition exhibits a hysteresis of 100-150 K. Average inclusion sizes ranged from a few nm to some tens of nm. The x-ray diffraction...

  2. Experimental wear behaviour of cryogenically treated aluminium 6063 and 8011 materials

    Directory of Open Access Journals (Sweden)

    K. K. Padmanabhan

    2016-12-01

    Full Text Available The aim of this paper is to focus on the effect of cryogenic treatment on the microstructure, mechanical and wear properties of Al 6061 and Al 8011. The first objective was to understand the degree to which wear behaviour has shown improvement with aluminium grades being treated cryogenically on the specimens. To conduct wear test Aluminium experimental investigation has been carried out on aluminium alloys with cryogenic coolants. The cryogenic coolant has increased the wear resistance properties of aluminium upto 25% when compared to wear of non-cryogenically treated aluminium. The cryogenic treatment was carried out under three different timings for three different rpm’s under varying loads. The paper also studies the micro structural changes under these varying conditions. The experimental investigation of the paper concludes that cryogenically treated aluminium shows increase in wear resistance of nearly 25%.

  3. Simulation of Acoustic Wave Propagation in Aluminium Coatings for Material Characterization

    Directory of Open Access Journals (Sweden)

    Eva Grünwald

    2017-12-01

    Full Text Available Aluminium coatings and their characterization are of great interest in many fields of application, ranging from aircraft industries to microelectronics. Here, we present the simulation of acoustic wave propagation in aluminium coatings via the elastodynamic finite integration technique (EFIT in comparison to experimental results. The simulations of intensity (I–defocus (z curves, obtained by scanning acoustic microscopy (SAM, were first carried out on an aluminium bulk sample, and secondly on a 1 µm aluminium coating deposited on a silicon substrate. The I(z curves were used to determine the Rayleigh wave velocity of the aluminium bulk sample and the aluminium coating. The results of the simulations with respect to the Rayleigh velocity were corroborated by non-destructive SAM measurements and laser ultrasonic measurements (LUS.

  4. Aluminium in food and daily dietary intake assessment from 15 food groups in Zhejiang Province, China.

    Science.gov (United States)

    Zhang, Hexiang; Tang, Jun; Huang, Lichun; Shen, Xianghong; Zhang, Ronghua; Chen, Jiang

    2016-06-01

    Aluminium was measured in 2580 samples of 15 food groups and dietary exposure was estimated. Samples were purchased and analysed during 2010 to 2014. High aluminium levels were found in jellyfish (mean 4862 mg/kg), laver (mean 455.2 mg/kg) and fried twisted cruller (mean 392.4 mg/kg). Dietary exposure to aluminium was estimated for Zhejiang residents. The average dietary exposure to aluminium via 15 food groups in Zhejiang Province was 1.15 mg/kg bw/week, which is below the provisional tolerable weekly intake of 2 mg/kg bw /week. Jellyfish is the main Al contributor, providing 37.6% of the daily intake via these 15 food groups. This study provided new information on aluminium levels and assessment of aluminium (Al) dietary exposure in Zhejiang Province of China.

  5. RESPONSE OF PHENOLIC METABOLISM INDUCED BY ALUMINIUM TOXICITY IN FAGOPYRUM ESCULENTUM MOENCH. PLANTS.

    Science.gov (United States)

    Smirnov, O E; Kosyan, A M; Kosyk, O I; Taran, N Yu

    2015-01-01

    Buckwheat genus (Fagopyrum Mill.) is one of the aluminium tolerant taxonomic units of plants. The aim of the study was an evaluation of the aluminium (50 μM effect on phenolic accumulation in various parts of buckwheat plants (Fagopyrum esculentum Moench). Detection of increasing of total phenolic content, changes in flavonoid and anthocyanin content and phenylalanine ammonia-lyase activity (PAL) were revealed over a period of 10 days of exposure to aluminium. The most significant effects of aluminium treatment on phenolic compounds accumulation were total phenolic content increasing (by 27.2%) and PAL activity rising by 2.5 times observed in leaves tissues. Received data could be helpful to understand the aluminium tolerance principles and relationships of phenolic compounds to aluminium phytotoxicity.

  6. Response of phenolic metabolism induced by aluminium toxicity in Fagopyrum esculentum Moench. plants

    Directory of Open Access Journals (Sweden)

    O. E. Smirnov

    2015-12-01

    Full Text Available Buckwheat genus (Fagopyrum Mill. is one of the aluminium tolerant taxonomic units of plants. The aim of the study was an evaluation of the aluminium (50 µM effect on phenolic accumulation in various parts of buckwheat plants (Fagopyrum esculentum Moench.. Detection of increasing of total phenolic content, changes in flavonoid and anthocyanin content and phenylalanine ammonia-lyase activity (PAL were revealed over a period of 10 days of exposure to aluminium. The most significant effects of aluminium treatment on phenolic compounds accumulation were total phenolic content increasing (by 27.2% and PAL activity rising by 2.5 times observed in leaves tissues. Received data could be helpful to understand the aluminium tolerance principles and relationships of phenolic compounds to aluminium phytotoxicity.

  7. Corrosion behaviour of laser-cleaned AA7024 aluminium alloy

    Science.gov (United States)

    Zhang, F. D.; Liu, H.; Suebka, C.; Liu, Y. X.; Liu, Z.; Guo, W.; Cheng, Y. M.; Zhang, S. L.; Li, L.

    2018-03-01

    Laser cleaning has been considered as a promising technique for the preparation of aluminium alloy surfaces prior to joining and welding and has been practically used in the automotive industry. The process is based on laser ablation to remove surface contaminations and aluminium oxides. However the change of surface chemistry and oxide status may affect corrosion behaviour of aluminium alloys. Until now, no work has been reported on the corrosion characteristics of laser cleaned metallic surfaces. In this study, we investigated the corrosion behaviour of laser-cleaned AA7024-T4 aluminium alloy using potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET). The results showed that the laser-cleaned surface exhibited higher corrosion resistance in 3.5 wt.% NaCl solution than as-received hot-rolled alloy, with significant increase in impedance and decrease in capacitance, while SVET revealed that the active anodic points appeared on the as-received surface were not presented on the laser-cleaned surfaces. Such corrosion behaviours were correlated to the change of surface oxide status measured by glow discharge optical emission spectrometry (GDOES) and X-ray photoelectron spectroscopy (XPS). It was suggested that the removal of the original less protective oxide layer consisting of MgO and MgAl2O4 on the as-received surfaces and the newly formed more protective oxide layer containing mainly Al2O3 and MgO by laser cleaning were responsible for the improvement of the corrosion performance.

  8. Non-LTE aluminium abundances in late-type stars

    Science.gov (United States)

    Nordlander, T.; Lind, K.

    2017-11-01

    Aims: Aluminium plays a key role in studies of the chemical enrichment of the Galaxy and of globular clusters. However, strong deviations from LTE (non-LTE) are known to significantly affect the inferred abundances in giant and metal-poor stars. Methods: We present non-local thermodynamic equilibrium (NLTE) modeling of aluminium using recent and accurate atomic data, in particular utilizing new transition rates for collisions with hydrogen atoms, without the need for any astrophysically calibrated parameters. For the first time, we perform 3D NLTE modeling of aluminium lines in the solar spectrum. We also compute and make available extensive grids of abundance corrections for lines in the optical and near-infrared using one-dimensional model atmospheres, and apply grids of precomputed departure coefficients to direct line synthesis for a set of benchmark stars with accurately known stellar parameters. Results: Our 3D NLTE modeling of the solar spectrum reproduces observed center-to-limb variations in the solar spectrum of the 7835 Å line as well as the mid-infrared photospheric emission line at 12.33 μm. We infer a 3D NLTE solar photospheric abundance of A(Al) = 6.43 ± 0.03, in exact agreement with the meteoritic abundance. We find that abundance corrections vary rapidly with stellar parameters; for the 3961 Å resonance line, corrections are positive and may be as large as +1 dex, while corrections for subordinate lines generally have positive sign for warm stars but negative for cool stars. Our modeling reproduces the observed line profiles of benchmark K-giants, and we find abundance corrections as large as -0.3 dex for Arcturus. Our analyses of four metal-poor benchmark stars yield consistent abundances between the 3961 Å resonance line and lines in the UV, optical and near-infrared regions. Finally, we discuss implications for the galactic chemical evolution of aluminium.

  9. Methods for production of aluminium powders and their application fields

    Energy Technology Data Exchange (ETDEWEB)

    Gopienko, V.G.; Kiselev, V.P.; Zobnina, N.S. (Vsesoyuznyj Nauchno-Issledovatel' skij i Proektnyj Inst. Alyuminievoj, magnievoj i ehlektrodnoj promyshlennosti (USSR))

    1984-12-01

    Different types of powder products made of alluminium and its alloys (powder, fine powders, granules and pastes) as well as their basic physicochemical properties are briefly characterized. The principle methods for alluminium powder production are outlined: physicochemical methods, the melt spraying by compressed gas being the mostly developed among them, and physico-mechanical ones. Main application spheres for powder productions of aluminium and its alloys are reported in short.

  10. Natural Aging Behaviour Of AA6111 Aluminium | Quainoo | Ghana ...

    African Journals Online (AJOL)

    Natural aging is observed to affect the kinetic reaction of AA6111. Dans la campagne continue pour la réduction en poids dans le nouveau modèle d\\' automobile, les séries 6000 d\\' aluminium en alliage ont émergé comme le matériau de feuille de carrosserie la plus prometteuse endurcirable avec l\\'âge dans l\\'industrie de ...

  11. Friction factor of CP aluminium and aluminium–zinc alloys

    Indian Academy of Sciences (India)

    The Rock- well hardness of all the samples were also measured. 3. Results and discussion. Friction factor, m, of CP aluminium is given in table 1 for various test temperatures. The friction factor, m, was low. (0⋅09–0⋅34) up to 673 K but it reached 0⋅90 at 773 K ex- hibiting sticking behaviour. Figure 5 shows the plot of.

  12. Cyclic behaviour and fatigue life prediction in welded aluminium joints

    International Nuclear Information System (INIS)

    Kosteas, D.

    1979-01-01

    The paper gives an overall state-of-the-art view of international attempts to find a solution, describes cyclic stress-strain behavior for the different zones of aluminium weldments, as stated above, states results from a recent research program of the Versuchsanstalt Stahl, Holz, und Steine in Karlsruhe and gives a step by step model for the calculation procedure of fatigue life. (orig.) 891 RW/orig. 892 RKD [de

  13. Configuration and mobility of hydrogen implanted in aluminium

    International Nuclear Information System (INIS)

    Bugeat, J.P.; Chami, A.C.; Ligeon, E.

    1976-01-01

    Localization methods through channeling and nuclear reaction analysis using low energy ion beam were applied to the study of deuterium and hydrogen implanted in aluminium single crystals. It was shown that implanted hydrogen occupies a tetrahedral site in the lattice as far as the implantation temperature is lower than 175K. This fact is interpreted by considering an interaction between hydrogen and monovacancies created during the implantation [fr

  14. Numerical modeling of aluminium foam on two scales

    Czech Academy of Sciences Publication Activity Database

    Němeček, J.; Denk, F.; Zlámal, Petr

    2015-01-01

    Roč. 267, September (2015), s. 506-516 ISSN 0096-3003 R&D Projects: GA ČR(CZ) GAP105/12/0824 Institutional support: RVO:68378297 Keywords : closed-cell aluminium foam * Alporas * multiscale modeling * homogenization * FFT * finite element modeling Subject RIV: JI - Composite Materials Impact factor: 1.345, year: 2015 http://www.sciencedirect.com/science/article/pii/S0096300315001162

  15. Texture development during recrystallization of aluminium containing large particles

    DEFF Research Database (Denmark)

    Juul Jensen, Dorte; Hansen, Niels; Humphreys, F. J.

    1985-01-01

    The recrystallization process in heavily deformed commercially pure aluminium containing large intermetallic particles was studied by in situ neutron diffraction texture measurements and various microscopical techniques including texture measurements in local areas and simultaneous determination...... of orientations takes place close to larger particles or clusters of particles early in the recrystallization process. The texture of fully recrystallized material, however, contains only a relatively weak random component showing that the randomisation effect of the particles was limited. This was ascribed...

  16. Development of Niobium Boron grain retainer for aluminium silicon alloys

    OpenAIRE

    Nowak, Magdalena

    2011-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University Aluminium castings with a large grain structure have poor mechanical properties which are primarily due to casting defects as opposed to fine grain structure. The grain refinement practice using chemical addition is well established for wrought alloys, however in the case of casting alloys, the practice of adding grain refiners and the impact on castability is not well established. The additio...

  17. Study of twist boundaries in aluminium. Structure and intergranular diffusion

    International Nuclear Information System (INIS)

    Lemuet, Daniel

    1981-01-01

    This research thesis addresses the study of grain boundaries in oriented crystals, and more particularly the systematic calculation of intergranular structures and energies of twist boundaries of <001> axis in aluminium, the determination of intergranular diffusion coefficients of zinc in a set of twist bi-crystals of same axis encompassing a whole range of disorientations, and the search for a correlation between these experimental results and calculated structures

  18. Aluminium and Aroma Compound Concentration in Beer During Storage at Different Temperatures

    Directory of Open Access Journals (Sweden)

    Marija Soldo Gjeldum

    2006-01-01

    Full Text Available Problem of aluminium in beer has been elaborated in several papers over the last decade. However, the effect of aluminium on organoleptic properties of beer has been observed in few papers where it has been stated that aluminium gives beer a »metallic« and bitter flavour without any observations on particular aroma compound changes. Also, the number of reports on precise changes of aroma components throughout different storage conditions is surprisingly scarce. In order to investigate the changes of aluminium concentration along with aroma compound changes, graphite furnace-atomic absorption spectrophotometry (GF-AAS with Zeeman background correction and gas chromatography with static headspace sampler (GC-HSS were used in this work. Analyses were conducted periodically throughout seven months of storage on three different brands of beer from name breweries. Samples were taken before and after filling in aluminium cans. One part of samples was stored in a refrigerator (4 °C and the other in a thermostatic chamber (22 °C. The effects of beer brand and storage conditions on aluminium concentration and level of aroma compounds were measured. To prove the effect of aluminium concentration on the changes of aroma compounds, the adequate level of aluminium sulphate was added to bottled beer samples stored at 28 °C. Although different beer types showed significantly different aluminium concentration, it could be the result of other factors (different batches of identical beer type showed significantly different aluminium concentration as well. Samples that were stored in the refrigerator were protected from aluminium migration from the can to the beer and showed increased aroma stability. Level of aroma constituents of analyzed beer brands was significantly different. Elevated aluminium concentration did not have any noticeable effect on the level of aroma compounds in beer samples stored at 28 °C.

  19. Physical and chemical bases of complex processing of aluminium production wastes

    International Nuclear Information System (INIS)

    Ruziev, D.R.

    1998-01-01

    The purpose of the present work is development of scientific bases of processing of aluminium production wastes. For this it was necessary consider following base processes: water extraction of useful components from mud of aluminium production; receiving of soda ash, liquid glass, glaze, cryolite and alumina from aluminium production wastes; remove of carbon from mud and screening of refuse tip by flotation and incineration method

  20. Anisotropic behaviour law for sheets used in stamping: A comparative study of steel and aluminium

    OpenAIRE

    Sinou, Jean-Jacques; Macquaire, Bruno

    2008-01-01

    International audience; For a car manufacturer, reducing the weight of vehicles is an obvious aim. Replacing steel by aluminium moves towards that goal. Unfortunately, aluminium's stamping numerical simulation results are not yet as reliable as those of steel. Punch-strength and spring-back phenomena are not correctly described. This study on aluminium validates the behaviour law Hill 48 quadratic yield criterion with both isotropic and kinematic hardening. It is based on the yield surface an...