摘要 :
Copper concentration and speciation were determined in influent and effluent waters collected from eight power stations that used copper alloys in their cooling systems. Quantities of copper associated with particles, colloids, an...
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Copper concentration and speciation were determined in influent and effluent waters collected from eight power stations that used copper alloys in their cooling systems. Quantities of copper associated with particles, colloids, and organic and inorganic ligands differed with the site, season, and mode of operation of the station. Under normal operating conditions, the differences between influent and effluent waters were generally small, and most of the copper was in bound (complexed) species. However, copper was high in concentration and present in labile species during start-up of water circulation through some cooling systems and during changeover from an open- to closed-cycle operation. Copper sensitivity of selected ecologically and economically important aquatic organisms was also evaluted. Our primary emphasis was on acute effects and most of the testing was performed under controlled laboratory conditions. However, sublethal effects of copper on a population of bluegills living in a power station cooling lake containing water of low pH were also assessed. The toxic response to copper differed with the species and life stage of the animal and with the chemical form of copper in the water. (ERA citation 09:008631)
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摘要 :
Most researchers have concluded that the uncomplexed Cu ion is the primary toxic or bioavailable species while others have suggested that hydroxide, carbonate and organically complexed species may also be toxic. Because the comput...
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Most researchers have concluded that the uncomplexed Cu ion is the primary toxic or bioavailable species while others have suggested that hydroxide, carbonate and organically complexed species may also be toxic. Because the computed activities of the aqueous Cu species are both highly dependent on the thermodynamic data used and highly correlated with each other, it is difficult to show definitively that the individual chemical species-toxicity correlations are valid and it is virtually impossible to determine the statistical relationship between toxicity and copper aqueous speciation using traditional statistical methods. The proposed methodology consists of first computing the aqueous speciation of Cu using the geochemical model, MINTEQ, with a thoroughly reviewed and partially validated thermodynamic data base for Cu. Finally, multivariate statistical techniques applicable to collinear data and underdetermined systems are applied to the activities of the Cu species and the toxicity measurements to determine the relationship between the speciation and toxicity. A reevaluation using this methodology indicates that the primary bioavailable species are the hydroxide species and that the carbonate and phosphate species are not toxic. Based on the results of the statistical analyses and the properties of the statistical techniques, it appears that a combination of factor analysis and ridge regression yield the most information about the structure of the collinearities and provide estimates of the coefficients and the bias. 35 references, 1 figure, 1 table. (ERA citation 09:036383)
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A process for vacuum brazing beryllium copper anode assemblies was required for the Plasma Electrode Pockels Cell System, or PEPC, a component for the National Ignition Facility (NIF). Initial problems with the joint design and we...
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A process for vacuum brazing beryllium copper anode assemblies was required for the Plasma Electrode Pockels Cell System, or PEPC, a component for the National Ignition Facility (NIF). Initial problems with the joint design and wettability of the beryllium copper drove some minor design changes. Brazing was facilitated by plating the joint surface of the beryllium copper rod with silver 0.0006 inch thick. Individual air sampling during processing and swipe tests of the furnace interior after brazing revealed no traceable levels of beryllium.
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The oxygen binding site of hemocyanin has two copper atoms coordinated to the side chains from the polypeptide chain. Copper extended x-ray absorption fine structure (EXAFS) and absorption edges of the protein were studied. Compar...
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The oxygen binding site of hemocyanin has two copper atoms coordinated to the side chains from the polypeptide chain. Copper extended x-ray absorption fine structure (EXAFS) and absorption edges of the protein were studied. Comparison of EXAFS from three molluscan oxyhemocyanins (Megathura crenulata, the alpha /sub c/ and beta /sub c/ of Helix pomatia) indicates that the structure of the binuclear copper sites is very similar in the three proteins. Four different forms (oxy, deoxy, dimer, and half-apo) of hemocyanin from M. crenulata were selected for a detailed study. A structural model of the oxygen binding site is proposed based on the EXAFS results. The oxygen binding site in hemerythrin contains two iron atoms coordinated to the side chains from the polypeptide chain. Iron EXAFS and absorption edges from Phascolopsis gouldii hemerythrin were studied. Five different forms (oxy, deoxy, aquomet, hydroxomet, and azidomet) of the protein were selected for this study. A structural model of the oxygen binding site in hemerythrin is proposed. (ERA citation 09:027102)
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Nuclear model codes were used to compute cross sections for neutron-induced reactions on both sup 63 Cu and sup 65 Cu for incident energies from 1 to 20 MeV. The input parameters for the model codes were determined through analysi...
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Nuclear model codes were used to compute cross sections for neutron-induced reactions on both sup 63 Cu and sup 65 Cu for incident energies from 1 to 20 MeV. The input parameters for the model codes were determined through analysis of experimental data in this energy region. Discussion of the models used, the input data, the resulting calculations, extensive comparisons to measured data, and comparisons to the Evaluated Nuclear Data File (ENDF/B-V) for Cu (MAT 1329) are included in this report. (ERA citation 09:046977)
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The main objective of this research was to determine the role of dissolved sulfide pollutants on the seawater corrosion of two copper nickel alloys--90:10 Cu:Ni (CA 706) and 70:30 Cu:Ni (CA 715). Electrochemical techniques were us...
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The main objective of this research was to determine the role of dissolved sulfide pollutants on the seawater corrosion of two copper nickel alloys--90:10 Cu:Ni (CA 706) and 70:30 Cu:Ni (CA 715). Electrochemical techniques were used to monitor corrosion rates in rotating cylinder experiments and in flow loop experiments. The effects of flow (velocity) and the composition of the seawater environment were considered. The highlights of this work are as follows: (1) Electrochemical methods are suitable for monitoring the corrosion rate of copper-nickel alloys in seawater if certain precautions are taken. (2) The presence of sulfide or one of several sulfide oxidation products turns noncorrosive deaerated seawater into a comparatively corrosive environment. (3) Sulfide-polluted deaerated seawater is less corrosive than unpolluted aerated seawater at Reynolds numbers up to 74,000 (velocities up to 5 m/s). (4) When the velocity of aerated seawater is increased from 2 m/s to 3 m/s (Reynolds number from 30,000 to 44,000), 70:30 Cu:Ni undergoes a transition from fairly uniform mild corrosion to accelerated localized corrosion. This breakaway corrosion phenomenon is interpreted in terms of a 'breakaway potential.' (Author)
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The considerations necessary for the design and construction of an inexpensive, reliable copper halide laser are presented. A broad range of parameters which govern the output of the double-pulse copper-halide laser was studied. T...
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The considerations necessary for the design and construction of an inexpensive, reliable copper halide laser are presented. A broad range of parameters which govern the output of the double-pulse copper-halide laser was studied. The laser has an optimum operating temperature which is different for each halide uCl, CuBr, CuI), but corresponds to a halide vapor pressure of about 0.1 torr for all three halides. At low repetition rates the highest laser output is achieved with helium as buffer gas. The laser output increases linearly with laser tube cross-section. As the tube diameter is increased, the dissociation energy must be increased, but not the excitation energy. A thyratron bias circuit has been developed which permits both dissociation and excitation pulses to be obtained from the same capacitor (with a small delay) without thyratron latch. Use of the single thyratron reduces the laser cost considerably. A laser tube with an operating life of many hundreds of hours has been designed. The description of a laser with an output of 0.5 mJ per pulse at repetition rates of up to 120 pulses per second is given. The design and construction of various components of this laser are given in detail. (Atomindex citation 11:502992)
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Copper and some of its alloys have found wide applications in the electrical industry due to their high electrical and thermal conductivity. This report covers mainly the range of application of high conductivity coppers with litt...
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Copper and some of its alloys have found wide applications in the electrical industry due to their high electrical and thermal conductivity. This report covers mainly the range of application of high conductivity coppers with little alloying elements and briefly describes production of such coppers as electrolytic tough pitch copper, arsenical copper, cadmium copper, chromium copper, silver copper, sulphur copper, and tellurium copper.
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