The deformation of copper whiskers was studied by testing them at room and low temperatures in a specially built tensometer. The whiskers were grown by the standard method of hydrogen reduction of cupric chloride. X-ray studies of straight and kinked whiskers showed that crystallographic directions of the whisker axis other than <100>, <110>, and <111> are possible. In addition the formation of coherent twins is possible in copper whiskers grown by the above method. Tensile tests at various temperatures revealed a step effect, a hesitant flow and yield points in the flow region which were explained by proposing dislocation mechanisms. Tensile tests in dilute sulphuric acid showed that the oxide coating is not solely responsible for the strength of whiskers. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

The corrosion rate of copper in deaerated aqueous, sulfuric-acid solutions, with regard to the effect of strain, temperature and electrolyte concentration was studied. Copper in the form of wire was subjected to applied stresses of 1728, 8640, and 17,280 pounds per square inch. Five temperatures in the range 15°C to 75°C. were investigated for electrolyte concentrations of 0.1, 0.5 and 1.0 molar sulfuric acid. The rate of corrosion was followed by noting the rate of copper uptake by the solution through a polarographic analysis run periodically for up to 30 hours. Reproducible results were obtained, it was found that: 1. The rate of reaction for the dissolution of copper in sulfuric acid was first order with respect to cupric ion concentration. 2. Experimentally, the reaction rate was pseudo-first order with respect to hydrogen ion activity. 3. Stress, in general, increased the reaction rate slightly, the effect becoming less at higher temperatures. 4. The activation energy for unstressed corrosion was 10.6 Kcal. for the temperature range 15-75 degrees. 5. For 1.0M and 0.5M acid solutions, stress decreased the activation energy and hence increased the reaction rate. 6. The average increase in reaction rate for 10 degree changes in temperature between 15 and 75 degrees was about 1.5. 7. A diffusion controlled mechanism could be proposed for the dissolution of copper in sulfuric acid solutions. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

Monoaniline and monopyridine adducts of copper (II) ortho-methyl-, meta-methyl-, ortho-bromo-, and meta-bromobenzoate, and mono-aniline adducts of copper (II) ortho-chloro-, para-methyl-, and para-bromobenzoate were prepared. Magnetic susceptibility measurements of these compounds were made at room temperature on Gouy and Faraday apparatus. Variable temperature susceptibility measurements over the range 77 - 330°K were made employing a Gouy apparatus. Visible diffuse reflectance spectra as well as solution spectra of these compounds were also recorded. Molecular weight measurements could be obtained only for a few of the compounds because of their marked insolubility. Structure and bonding are discussed in the light of the results. / Science, Faculty of / Chemistry, Department of / Graduate

We have studied the quantum diffusion of positive muons in pure copper over the temperature range 20 mK ≤ T ≤ 200 K using the technique of muon spin relaxation (μSR). The rate of diffusion has been deduced from its effect upon the muon polarization function. The measurements were made in a weak longitudinal external magnetic field, where the spin relaxation has proved to be the most sensitive to the muon hop rate below 150 K. Our results for the behaviour of the muon hop rate are well explained by the recently developed theories of the quantum diffusion of light interstitials in metals by Kondo, Yamada and others. These theories stress the effects of the conduction electrons in the metal in providing a form of "friction", retarding the diffusion process. In addition we have utilized the technique of level-crossing resonance spectroscopy, in its first application to μSR measuring the electric quadrupole interaction strength of the copper nuclei. These results have enabled us to show that the muon occupies the same octahedral site at all the temperatures studied. This allows one to rule out the possibility of metastable muon sites contributing to any significant portion of the muon polarization. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The injection dynamics and related accretion build up, as well as bath motion and heat losses in copper converters, have been investigated. The studies involved physical and mathematical models coupled with plant trials at four copper smelters to examine gas discharge phenomena, bath slopping and heat transfer within the converter. The laboratory work, performed on a 1|4th scale model of a converter, indicated significant tuyere interaction. Air discontinuously discharges into the bath with a frequency which increases with gas flow rate and is affected by the bath circulation velocity in the tuyere region. Measurements have delineated slopping behaviour in terms of tuyere submergence and the buoyancy power input to the bath. The industrial trials were conducted in Peirce-Smith, Hoboken and Inspiration converters under normal conditions. A tuyerescope attached to the back of a tuyere permitted the direct observation of accretion growth and the sampling of accretions during blowing. The tests indicated that the copper converter operates under bubbling conditions. Pressure pulses from the tuyeres revealed that in non-ferrous submerged injection processes three regimes of gas-liquid interaction can be identified: bubbling, unstable envelope and channelling. The relative dominance of each regime is affected by tuyere line erosion, viscosity of the bath and tuyere submergence. Analysis of the accretion samples revealed that accretions in the copper converter form mainly by the solidification of bath at the tuyere tip. Oxygen enriched air does not prevent accretion formation, but seems to produce a softer, easy-to-punch accretion. The type of puncher as well as punching frequency affect conditions inside the tuyere pipe and this could have an influence on accretion formation. The mathematical heat transfer model indicated that when the converter is out of the stack, heat losses through the mouth of the converter cause the internal surface to cool rapidly which may lead to freezing at the tuyere line and tuyere blockage when blowing is resumed. The temperature gradient, localized to within 60-80 mm of the refractory inside wall, changes markedly within the first minutes of the converter being out of stack. This may generate thermal stresses in the converter wall and contribute to refractory erosion at the tuyere line. Covering the converter mouth during out-of-stack periods significantly reduces the change in temperature gradient at the inside wall as well as heat losses from the converter. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

Significant differences were found to exist in the copper tolerance of the life-history stages of the marine copepod, Tiqriopus californicus, using artificial seawater as medium. The copper response of Tigriopus to copper was found to occur predominantly over the concentration range 1.0X10⁻⁶ M to 1.5X10⁻⁵ M. The N-2 was the most sensitive and the C-6 was the most tolerant life-history stage. Copper equilibrated with the food of Tiqriopus did not significantly affect adult fecundity (between 1.0x10⁻¹⁰ and 1.0X10⁻⁶ M Cu) or mortality (between 1.0x10⁻¹⁰ and 1.0X10⁻⁵ M). Copper equilibrated with SOW did not significantly alter the rate of egg survival (between 1.0X10⁻⁹ and 1.0X10⁻⁶ M) or naupliar activity (between 1.0x10⁻⁸ and 1.0X10⁻⁶ M). Exposure to widely varying but natural ecological conditions appears to have increased the tolerance of Tigriopus to unnatural stress. The copper-manganese interaction observed for some species of phytoplankton such as Thalassiosira pseudonana was not found to hold for Tiqriopus in SOW medium. No significant reduction in copper toxicity was observed upon addition of manganese (between 1.0 X 10⁻⁶ and 1.0X10⁻⁴ M) to copper 10X10⁻⁶ M) solutions. An attempt was made to quantify the proportion of copper and manganese in biologically available forms (i.e., able to react with or pass through biological membranes) using the cation resin technique of Zorkin et al., ( 1986). It is thought that this attempt failed due to the resin columns being supersaturated with metal ions. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

There has been significant increase in production of copper treated lumber since a voluntary halt of chromated copper arsenate (CCA) for residential use by the wood treating industry. Disposal of copper treated wood wastes has become an environmental issue for companies using these products for residential applications. This study evaluated recovery of copper from sawdust of copper azole(CA),micronized copper azole(MCA), alkaline copper quat(ACQ), and micronized copper quat(MCQ) using three different extraction procedures; toxicity characteristic leaching procedure(TCLP), sonication with heated water, and sonication with room temperature water. Two extraction fluids were used, monoethanolamine (MEA) and acidic water. No significant differences in copper recovery were observed between CA, MCA, MCQ, and ACQ using acidic water in any extraction procedures. Copper recovery was significantly higher for MEA than acidic water for all preservatives. Significantly higher levels of copper were recovered for CA and MCA than ACQ and MCQ with MEA extraction fluid.

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Theaters used to an important civic space, and nowadays urban spaces have begun to be viewed as theatrical spaces. Theaters as well as cinemas are primarily shared spaces. As online viewing of films has become more prevalent, it is pertinent to explore how a shared experience can be enhanced. An outdoor theater where neighbors could gain access by foot, an atrium where preview viewing, discussion and gallery viewing could happen concurrently, are a few examples of what this multiplex offers. The multiplex is located at Van Ness Metro Station facing Connecticut Ave in Washington D.C. The Multiplex comprises eleven movie theaters with seating capacity ranging from 35 to 150, an outdoor theater, a restaurant and several roof terraces. / Master of Architecture