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1
Sarson, Stuart C. "Investigations in the copper-lead system." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239160.
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McClinton, Martin Andrew. "An investigation of the copper-difluorodihalomethane-amide trifluoromethylating system." Thesis, University of York, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329701.
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Jackson, A. R. W. "The imidazolethione/copper system : Coordination chemistry and corrosion inhibition." Thesis, University of Newcastle Upon Tyne, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371068.
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Poole, Martin. "Progress towards the development and implementation of an unambiguous copper wire fingerprinting system." Thesis, Rhodes University, 2003. http://eprints.ru.ac.za/214/.
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Plana, Daniela. "An electrochemical investigation of electroless deposition : the copper-DMAB system." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/an-electrochemical-investigation-of-electroless-deposition-the-copperdmab-system(8478ea99-e05f-40c6-8260-2e8788f38efa).html.
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An electrochemical study of the copper electroless deposition process, using dimethylamine borane as a reducing agent, has been performed, in order to gain further understanding of the mechanism and kinetics of electroless deposition. An in-depth study of the electro-oxidation of dimethylamine borane (DMAB) was additionally carried out, due to its increasing relevance, not only in electroless deposition, but also in fuel cell technology. DMAB oxidation was studied using different experimental techniques such as voltammetry, chronoamperometry, single-crystal electrochemistry and in-situ Fourier Transform infrared spectroscopy, which demonstrated that adsorption of the DMAB molecule, and its intermediates, plays an important role in the oxidation mechanism and kinetics. The initial dissociation process is catalysed by the presence of metallic surfaces and the applied potential. On gold surfaces, DMAB undergoes a three-electron transfer at low overpotentials, with a further oxidation process of up to six electrons occurring at high overpotentials. Chemical interactions with gold oxide produce further oxidation of the DMAB molecule. In the potential region of gold oxide formation, in highly alkaline media, the dimethylamine is also oxidised. The voltammetric behaviour of bipolar cells was studied using model reversible and quasi-reversible redox couples, in conjunction with numerical simulations of the system. DMAB oxidation and copper electrodeposition were studied separately and together using the bipolar cell, providing useful information of the 'coupling' effects between the cathodic and anodic processes of electroless deposition. The ability to quantify side reactions associated with electroless plating, namely hydrogen evolution in the copper-DMAB system, was also demonstrated. The kinetics of the copper-DMAB electroless system was studied in detail, using the electroless bath and a galvanic cell configuration. The fact that the rate of deposition decreased upon the physical separation of the two half-reactions, as well as the observed catalysis of the oxidation of DMAB by copper surfaces, lead to the conclusion that the mixed potential theory (MPT) does not apply to this system. Faradaic efficiencies never reached 100% due to the parasitic side reactions mentioned above; the latter were especially prominent in the early stages of deposition. Crystalline copper films were obtained, with a higher fraction of Cu (111) than expected for polycrystalline copper, while the roughness of the deposits was found to increase with deposition time.
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au, sblack@ccwa wa gov, and Silvia Beatriz Black. "The thermodynamic chemistry of the aqueous copper-ammonia thiosulfate system." Murdoch University, 2006. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20070508.154242.
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A fundamental thermodynamic study was undertaken in order to establish the speciation of copper(I) and copper(II) during the leaching and recovery of gold from thiosulfate-copper-ammonia solutions. Despite considerable research into this complex leaching system, the lack of important fundamental chemistry has delayed the implementation of the thiosulfate process as an alternative to cyanidation. Over the last two decades, research in this field has focused on the kinetics and electrochemistry of leaching, which involves the use of copper(II) as an oxidant. However, the fundamental thermodynamic data for copper(I) and copper(II) in this system is limited.
Ion association was found to significantly affect the dissociation constant of the ammonium ion in solutions containing sodium sulfate and/or sodium thiosulfate, thus influencing the free ammonia concentration in solution. These findings highlight the importance of using the correct dissociation constant value in thermodynamic studies that involve ammonia in order to obtain precise stability constants.
It has been established that the mixed-ligand complexes Cu(NH3)(S2O3)23- and Cu(NH3)(S2O3)- exist in solution and they are more stable than the other species Cu(S2O3)35-, Cu(NH3)2+ and Cu(NH3)3+ at high concentrations of ammonia and/or thiosulfate. The relative proportions of each two species is dependant on the [NH3]:[S2O32-] ratio in solution. This is reflected in two- and three- dimensional speciation diagrams that have been constructed for typical leaching and recovery processes using the stability constants obtained in this study. The 3-dimensional diagrams reveal subtle speciation trends that are not easily discernable from the 2-dimensional diagrams.
An investigation into the effect of high sulfate and chloride concentrations showed that these anions are not involved in the complexation with copper(I)-ammonia or copper(I)-ammonia-thiosulfate species under the experimental conditions studied. However, these anions and perchlorate formed relatively stable species with the copper(II)-ammine complexes in the absence of thiosulfate. Stability constants were obtained for the species Cu(NH3)4SO40, Cu(NH3)4Cl+ and Cu(NH3)4ClO4+ and it is suggested that these anionic ligands form outer-sphere complexes with the Cu(NH3)42+ ion.
Various methods of predicting stability constants for mixed-ligand complexes from those for the corresponding single ligand systems have been evaluated for this copper(I) system. Although the results have not been quantitatively accurate, the trends suggest that an appropriate method may serve as a useful qualitative tool to predict the possible existence of mixed-ligand complexes.
The combined application of 2- and 3-dimensional speciation and potential diagrams could be used as a hydrometallurgical tool in the design, optimization and control of possible future processes for the extraction of gold using thiosulfate in the presence of copper ions and ammonia. The work presented in this thesis adds to our understanding of the chemistry of copper(I) and copper(II) in this leaching system.
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Black, Silvia Beatriz. "The thermodynamic chemistry of the aqueous copper-ammonia thiosulfate system." Black, Silvia Beatriz (2006) The thermodynamic chemistry of the aqueous copper-ammonia thiosulfate system. PhD thesis, Murdoch University, 2006. http://researchrepository.murdoch.edu.au/336/.
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A fundamental thermodynamic study was undertaken in order to establish the speciation of copper(I) and copper(II) during the leaching and recovery of gold from thiosulfate-copper-ammonia solutions. Despite considerable research into this complex leaching system, the lack of important fundamental chemistry has delayed the implementation of the thiosulfate process as an alternative to cyanidation. Over the last two decades, research in this field has focused on the kinetics and electrochemistry of leaching, which involves the use of copper(II) as an oxidant. However, the fundamental thermodynamic data for copper(I) and copper(II) in this system is limited.
Ion association was found to significantly affect the dissociation constant of the ammonium ion in solutions containing sodium sulfate and/or sodium thiosulfate, thus influencing the free ammonia concentration in solution. These findings highlight the importance of using the correct dissociation constant value in thermodynamic studies that involve ammonia in order to obtain precise stability constants.
It has been established that the mixed-ligand complexes Cu(NH3)(S2O3)23- and Cu(NH3)(S2O3)- exist in solution and they are more stable than the other species Cu(S2O3)35-, Cu(NH3)2+ and Cu(NH3)3+ at high concentrations of ammonia and/or thiosulfate. The relative proportions of each two species is dependant on the [NH3]:[S2O32-] ratio in solution. This is reflected in two- and three- dimensional speciation diagrams that have been constructed for typical leaching and recovery processes using the stability constants obtained in this study. The 3-dimensional diagrams reveal subtle speciation trends that are not easily discernable from the 2-dimensional diagrams.
An investigation into the effect of high sulfate and chloride concentrations showed that these anions are not involved in the complexation with copper(I)-ammonia or copper(I)-ammonia-thiosulfate species under the experimental conditions studied. However, these anions and perchlorate formed relatively stable species with the copper(II)-ammine complexes in the absence of thiosulfate. Stability constants were obtained for the species Cu(NH3)4SO40, Cu(NH3)4Cl+ and Cu(NH3)4ClO4+ and it is suggested that these anionic ligands form outer-sphere complexes with the Cu(NH3)42+ ion.
Various methods of predicting stability constants for mixed-ligand complexes from those for the corresponding single ligand systems have been evaluated for this copper(I) system. Although the results have not been quantitatively accurate, the trends suggest that an appropriate method may serve as a useful qualitative tool to predict the possible existence of mixed-ligand complexes.
The combined application of 2- and 3-dimensional speciation and potential diagrams could be used as a hydrometallurgical tool in the design, optimization and control of possible future processes for the extraction of gold using thiosulfate in the presence of copper ions and ammonia. The work presented in this thesis adds to our understanding of the chemistry of copper(I) and copper(II) in this leaching system.
8
Barker, Simon William. "Diffusion induced liquid film migration in the aluminum-copper system /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/NQ42721.pdf.
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Bravo, de Nahui Flora. "Mass transfer behaviour for a packed bed copper cementation system." Thesis, University of Exeter, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234559.
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Boston, Rebecca Helen. "Control of crystallisation in the yttrium barium copper oxide system." Thesis, University of Bristol, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.686173.
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The control of crystallisation of complex oxides on the nano- and macro-scale is vital for the progression of technology and the fundamental understanding of the processes which govern functional oxide synthesis. The use of biotemplates has been shown to be a highly effective means of controlling both the phase and morphology of complex oxides, with macro- and nano-structures being formed which would otherwise be impossible using standard synthetic techniques. One complex functional material, yttrium barium copper oxide (YBCO), has generated huge amounts of interest for its superconducting properties, in particular its relatively high transition temperature (93 K), however given the complex nature of its crystal structure, it has proved to be very difficult to illicit control over the crystallite growth on the nano- or larger scales. Standard synthetic techniques, whilst very effective in producing a pure phase, are either slow or prohibitively expensive, and, due to the processes involved, offer no control over the final morphology. Herein are presented several new methods for the production of superconducting YBCO, including macro-scale control of polycrystalline samples in the formation of hollow microspheres through the use of the polysaccharide dextran, monolithic foams and highly layered tapes using a graphene oxide template, and nano-scale control to produce nanowires, through which a type of nanowire growth, the microcrucible mechanism, which has been directly observed and characterised for the first time. In addition, two sulphur-containing templates, K-carrageenan and a barnacle cement protein, which were thought to be unsuitable for use with YBCO (and any other phases containing precursors which would form stable sulphates during synthesis) were also investigated and found, after careful optimisation of the synthesis protocol, to be useable under certain experimental constraints. This is significant as it means that sulphur-rich proteins can now be successfully used for the production of YBCO, with the possibility of creating designer morphologies, giving even higher control over crystallisation. Each templating protocol was fully investigated using the standard chemical and physical characterisation techniques such as powder X-ray diffraction and transmission electron microscopy, in order to examine the phases and morphologies produced, and the superconducting properties investigated using a superconducting quantum interference device magnetometer. Where appropriate a number of other techniques such as in situ measurements using heating stages or X-ray micro computer-aided tomography were employed to give a deeper understanding of each templated system. The templating systems detailed here for YBCO should be applicable for other complex oxides, with the insights gained into the mechanisms which govern the phases and morphologies formed allowing optimised systems to be more quickly developed. This may lead to further advances in the production of complex functional oxide materials
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Gendall, Ian Richard. "The porphyry copper system and the precious metal-gold potential." Thesis, Rhodes University, 1994. http://hdl.handle.net/10962/d1005604.
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It has been established that porphyry copper/copper-gold deposits have formed from I Ma to 2 Ga ago. Generally, they are related to the Mesozoic-Cenozoic interval with few reported occurrences from the Palaeozoic or Precambrian. A reason cited is the erosion of these deposits which are often related to convergent plate margins and orogenic belts. Observations of the alteration and mineralisation within and around porphyry copper/copper-gold systems have been included in numerous idealised models. These alteration and mineralisation patterns are dependent on the phases of intrusion, the tectonic setting and rock type, depth of emplacement and relationship to coeval volcanics, physiochemical conditions operative within and surrounding the intrusive and many other mechanical and geochemical conditions. Island arc and cratonic arc/margin deposits are generally considered to be richer in gold than their molybdenum-rich, intra-cratonic counterparts. Metal zonation may occur around these copper/copper-gold deposits, e.g. copper in the core moving out to silver, lead, zinc and gold. This zonation is not always present and gold may occur in the core, intermediate or distal zones. Examples of gold-rich porphyry deposits from British Columbia, Chile and the SW Pacific Island regions suggest gold is closely associated with the potassic-rich zones. Generally these gold-rich zones have greater than 2% magnetite and a high oxygen fugacity is considered to be an important control for gold deposition. High Cl contents within the magma are necessary for gold mobility within the host intrusive centres. Beyond this zone HS₂ becomes an important transporting ligand. Exploration for porphyry copper-gold deposits includes an integrated geological, geophysical and geochemical approach. Petrographic work through to Landsat imagery may be used to determine the chemical conditions of the system, ore association, favourable structural zones and alteration patterns, in order to focus exploration activities.
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Ur, Rehman Bilal. "Modelling a Mineral Froth Flotation Process : Case Study: Minerals process at Boliden AB." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-51600.
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We present an approach to model the dynamic of a copper flotation process. The conventional approach of system identification is applied to model the dynamics. In this research, experiments are performed to collect process data of determined input and output variables. It is followed by data pre-processing to handle outliers and to remove high frequency disturbances. Simulation and validation responses of linear estimated models, which captured the dynamic of the process, are presented. The long term goal is to use estimated models to design a models-based control system.
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Quaranta, Davide. "Analysis and Molecular Characterization of an Unusual Copper Inducible Homeostasis Mechanism in Pseudomonas putida KT2440." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/194391.
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The purpose of this research was to identify and characterize novel molecular mechanisms in copper homeostasis. Pseudomonas putida KT2440 is a soil bacterium studied for its potential use in bioremediation of soils contaminated with aromatic organic contaminants. The cinAQ operon was analyzed. cinAQ is transcribed in presence of copper. The product of cinA is a periplasmic azurin-like protein with a methionine and histidine rich region, characterized by a high redox potential (456 ±4 mV). CinQ was shown to be a pyridine nucleotide-dependent nitrile oxidoreductase that catalyzes the reduction of preQ₀ to preQ₁, the first committed step in the biosynthetic pathway leading to the production of the unusual nucleotide queuosine. Gene disruption of cinQ in Pseudomonas putida KT2440 and in Pseudomonas aeruginosa PAO1 did not result in a significant increase in copper sensitivity on disk assays. Furthermore, a P. putida KT2440 cinA mutant also did not present a greater sensitivity to copper on disk assays while cinA mutants in Pseudomonas aeruginosa PAO1 presented increased toxicity to copper compared to the wild-type. CinA is by sequence similarity proposed to be an electron shuttle, and was shown to be upregulated in the presence of copper. Increasing CinA levels in the periplasm after copper stress may represent a mechanism used to regenerate the multicopper oxidase CopA (involved in Cu(I) to Cu(II) oxidation). Alternatively, CinA could act as an electron shuttle that takes part in an alternative electron transport chain once redox active copper is available, or it could represent a periplasmic copper chaperon. CinQ is involved in the biosynthesis of the rare hyper-modified nucleotide queuosine, found in the wobble position of several tRNAs, and required to avoid the readthrough of the stop codon UAG. Transcription of cinAQ was shown to be under the control of the two component system CinR-CinS. CinS is a histidine kinase, with a sensor domain located in the periplasm. CinR is the cognate response regulator that activates transcription of genes upon phosphorylation from CinS. The CinR-CinS two component system was shown to be responsive to 0.5 LM copper. CinS displayed very high metal specificity and elicited a response only in the presence of copper and silver, but not other metals. Modeling of the CinS protein structure, performed using Swiss Model and using the periplasmic sensor DcuS from Escherichia coli as a template, identified a potential copper binding site, containing H37 and H147. Sequence alignment of copper sensing histidine kinases further identified other conserved residues in the periplasmic domain. Site-Directed Mutagenesis was used to generate CinS mutants that were tested for their ability to activate the cinAQ promoter in presence of Cu. When challenged with copper CinS mutant H37R and H147R had an almost 10 fold reduction in copper sensitivity compared to the wild-type, indicating a possible role in Cu coordination. Other CinS mutants responded similarly to the wild-type in the presence of 10 μM of Cu.
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Andrade, Cassandra Jo. "Background and Research on Copper Alloys as an Antimicrobial Surface and the CusB protein of the Copper-Transporting Efflux System CusCFBA." Thesis, The University of Arizona, 2010. http://hdl.handle.net/10150/146238.
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Bactericidal properties of copper surfaces have been investigated in search of selfsanitizing materials in food and healthcare industries. However, bacteria in these environments are rapidly acquiring antibiotic and heavy metal resistance, which is thought to be a co-selection process (Baker-Austin, 2006). Copper-resistant strains of Escherichia coli and Enterococcus faecium isolated from pigs fed copper sulfate were examined (Hasman, 2002). Survival of strains was tested by timed incubation on onesquare- inch copper alloys with varying degrees of moisture during inoculation of the surfaces. Results showed rapid killing of E. coli and E. faecium copper-resistant strains when samples were spread in a thin layer on alloys with 85 % or greater copper content. E. coli strains had short survival rates under dry conditions while E. faecium strains were less affected. Dry or wet inoculations had no effect on the survival rates on stainless steel, since strains survived equally and no die-off was seen. Re-inoculation with E. coli on the alloys every 3 hours over a 24-hour period showed no CFUs remaining at each time point tested while bacteria survived without reduction of CFUs on the stainless steel controls after 24 hours. Results indicate that the bactericidal properties of metallic copper surfaces can be effective in killing copper-resistant strains of E. coli and E. faecium.
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Henline, Kylie Marie. "Amine- and Sulfide-Sensing Copper(I) Iodide Films and the Structure, Dynamics, and Photophysics in the Copper(I) Iodide-Tetrahydrothiophene System." W&M ScholarWorks, 2014. https://scholarworks.wm.edu/etd/1539626958.
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Parmar, Paresh H. "An investigation into the possible neuroprotective role of melatonin in copper-loading." Thesis, Rhodes University, 2001. http://hdl.handle.net/10962/d1003261.
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Copper is an extremely toxic metal in biological systems and thus, its availability to the system, must be effectively and efficiently controlled. Copper is vital for life, as it is essential for critical enzymes in biological systems. It is free copper in the biological systems that is toxic, as free copper induces free radical generation, which disrupts lipid membranes, interacts with DNA causing mutations, and eventually leads to cell death. Wilson’s disease is a inherited copper disease, which results in hepatolenticular disease. Copper is unable to be excreted, and thus accumulates, eventually spilling over into the bloodstream from the liver, and “poisons” the patient. The Wilson’s disease patient leads a short life, due to neurological and hepatological problems. There is no cure for Wilson’s disease, only chelation therapy using potent chelators such as penicillamine and EDTA. Zinc, in high doses, can be used to compete with copper absorption. This has proved to be the only successful therapy at present. This study investigates the possible use of melatonin as a copper binder/chelator. Melatonin has been shown to interact with copper in vitro. By binding/chelating to copper, melatonin may inhibit copper-induced free radical generation, and thus prevent copper from interacting with DNA to cause mutations and act as a cytotoxin. In vivo studies on copper (2mg/kg) administered for 2-weeks and 6-weeks were carried out on Wistar rats. The potential of melatonin (12mg/kg) to prevent copper-induced cellular damage was investigated. The results indicate that melatonin does not protect the lipid membranes from copper-induced lipid peroxidation. In vitro investigations using 1mM, 5mM and 10mM copper and 5mM melatonin, show that melatonin prevents copper-induced lipid peroxidation at a copper concentration of 1mM (p<0.001). The 5mM and 10mM copper induces less lipid peroxidation, compared to the 1mM copper. It has been reported that metal ions, antioxidants and chelating agents can influence peroxide decomposition during the assay. Melatonin (5mM) administration does not significantly prevent copper-induced lipid peroxidation at 5mM and 10mM copper. It is possible that due to melatonin’s relatively low concentration, it is unable to inhibit lipid peroxidation induced by the copper. The chemical nature of the interaction between melatonin and copper was also investigated, using NMR, IR and electrochemistry techniques. The NMR and IR techniques show that melatonin coordinates with Cu²⁺ and not Cu¹⁺, at the carbonyl group of melatonin. The electrochemistry experiments using cyclic voltammetry and adsorptive stripping voltammetry, show that melatonin forms a strong bond with Cu¹⁺. Cu²⁺ prefers binding to oxygen, and that is clearly seen in the NMR and IR. Cu¹⁺ prefers binding to nitrogen and then oxygen, and this is seen in the electrochemistry, as Cu¹⁺ is forced to bind through one of the nitrogens on the melatonin. Previously, it has been shown that melatonin binds/chelates with Cu²⁺. Histochemical investigations show that copper administration for 2-weeks and 6-weeks, causes extensive mitochondrial damage in liver and kidney’s proximal convoluted tubule epithelium cells. Melatonin (12mg/kg) co-administration with copper for 2-weeks and 6-weeks did not significantly protect the mitochondria from copper-induced damage. Copper-specific stains (rhodanine, silver sulphide and rubeanic acid) were used to stain liver, brain and kidney tissue samples. Rhodanine and silver sulphide were equally sensitive in staining copper in the 2-week samples, but not at all in the 6-week samples. This could not be explained. Rubeanic acid was ineffective in all samples tested. Thus, it appears that specific copper stains cannot be used in making a definitive diagnosis in cases of copper overload, and that specific copper stains do not always correlate with a high concentration of copper present in tissues. Pineal organ culture was used to determine the effect of copper administration on pineal indole synthesis. Exogenous (³H) tryptophan was administered to the pineal organ cultures, and the level of (³H) pineal indoles synthesised, were measured. Pineals from 2-week and 6-week copper/melatonin treated animals exhibited paradoxical 5- methoxytryptophol (ML) levels, as compared to the 2-week and 6-week copper treated animals. The 2-week copper/melatonin administered animals, showed a decrease in the ML level (p<0.01), and the copper/melatonin administered for 6-weeks, showed an increase in the ML levels (p<0.01). This indicates that melatonin interacts with the HIOMT enzyme. Pineals from 6-week copper/melatonin treated animals, as compared to the 6-week copper treated animals, showed an increase in N-acetylserotonin levels. This indicates that melatonin prevents the inhibition of the NAT enzyme. The final experiment was to determine in vitro, the effect of Cu²⁺ and Cu¹⁺ administration, on mitochondrial electron transport chain. Rat liver homogenate was incubated with and solutions of Cu²⁺ (10mM) and Cu¹⁺ (10mM) and melatonin (10mM). Cu²⁺ administration caused an inhibition of the electron transport at t=0 and t=60, whereas Cu¹⁺ administration at t=0 caused an inhibition of electron transport, but at t=60, Cu¹⁺ administration stimulated electron transport. Melatonin administered with Cu²⁺, resulted in an inhibition of the electron transport chain at t=0 and t=60. The findings of this study indicate that melatonin might have a potentially beneficial effect in copper overloading, by binding/chelating copper.
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McCudden, Corey B. "Hydrothermal zoning in the copper-molybdenum system beneath Red Cone Peak, Colorado /." Connect to resource, 2006. http://hdl.handle.net/1811/24781.
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Miller, Owen David William. "Precious metal mineralization associated with the Coed-y-Brenin porphyry copper system, North Wales." Thesis, University of Aberdeen, 1993. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=236945.
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The Coed-y-Brenin system is a diorite-hosted porphyry copper deposit of early Ordovician age (Tremadoc) situated on the south eastern side of the Harlech Dome: a thick sequence of Cambrian and Ordovician sediments and volcaniclastics that were subject to greenschist facies metamorphism during the Caledonian Orogeny. The copper mineralization occurs as disseminations, coatings on hairline fractures and in late-stage quartz-sulphide-calcite veinlets. Pyrite and chalcopyrite are the main opaque phases but sulphosalts, tellurides and electrum are also present. The copper mineralization is largely confined to the diorite and micro-tonalite dykes and sills associated with the Rhobell Fawr Volcanic centre. This study has shown that epithermal style precious-metal mineralization is also developed in the Coed-y-Brenin area in the shales and siltstones of the Maentwrog and Ffestiniog Flags Formations. It is characterised by pyritization, sericitization and silicification. The gold and silver occur as electrum in fractures and also as tellurides in late stage quartz-pyrite veins. Both styles of mineralization share a close spatial association and are characterised by propylitic and phyllic alteration. Argillic and potassic assemblages are not developed. Geochemical analysis of mineralized and unmineralized material has shown that the diorite-hosted mineralization is enriched in Cu, Au and Ag and depleted in Zn while the epithermal mineralization displays enrichments in Au, Ag, As, Sb and the base metals. Rb:Sr ratios increase with increasing alteration in both styles of mineralization. Sulphur isotope studies have shown that both styles of mineralization have a common, probably magmatic, sulphur source. Fluid inclusion data and 0 and H isotope studies indicate that following magma emplacement and development of the porphyry copper mineralization a low temperature-low salinity meteoric hydrothermal system was established. Fluid inclusion data and 0 and H isotope studies indicate that following magma emplacement and development of the porphyry copper mineralization a low temperature-low salinity meteoric hydrothermal system was established. This was responsible for the late-stage quartzsulphide-calcite veins in the diorites and for all the sediment-hosted mineralization. The association between epithennal and porphyry deposits has become apparent in recent years but the Coed-y-Brenin system is unusual due to its Lower Palaeozoic age and because both styles of mineralization are developed at the same structural level. This study of the Coed-y-Brenin porphyry system demonstrates the potential for the development and preservation of epithermal mineralization in porphyry systems and also in older orogenic belts.
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Gilmer, Amy K. "Petrogenesis of the Don Manuel igneous complex and porphyry copper system, central Chile." Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702924.
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Porphyry copper deposits (PCDs) are associated with shallow-level, subvolcanic intrusions. While PCDs have been studied extensively, the petrology of the host intrusions have received relatively little attention because hydrolytic alteration often destroys the primary petrologic features. However, these features are key to understanding the trans-crustal arc magmatic processes that result in PCDs. The Don Manuel porphyry copper system of the Miocene-Pliocene PCD belt of central Chile, contains significant alteration, but it is localized, allowing investigation of the primary petrology in relatively fresh portions. Fieldwork and examination of drill cores enabled characterization of the Don Manuel igneous complex (DMIC). The DMIC consists of six intrusive units ranging from 53-74 wt.% Si02. Highresolution CA-ID-TIMS U-Pb and whole-rock 40Ar/39Ar dating indicate that the intermediate to felsic units were emplaced in pulses between 4.0-3 .6 Ma, making it the youngest documented PCD system in the Andes. The episodic emplacement of this igneous complex occurred on a timescale similar to eruption and degassing events in arc volcanic systems. Petrographic, geochemical and isotopic data establish the origin and assembly of the diverse magmas that comprise the DMIC. The magmas have undergone polybaric differentiation from parents with varying initial water contents. Mineral chemistry, coupled ~ith thermobarometry, constrain the petrogenesis of the DMIC, indicating that wet magmas began differentiating in the lower to middle crust and continued to evolve in shallow crustal reservoirs. Intermediate porphyry dikes associated with copper mineralization contain diverse crystal cargos that represent mush entrained from different depths, crystals originating in different magmas, and crystals grown in-situ from hybridized magmas. The petrologic complexity and episodic timescale observed in the porphyry copperrelated magmas is analogous to the open system, trans-crustal processes indicated arid observed in arc volcanic systems. Examination of other PCDs through this framework could provide additional information about key ore ingredients such as volatiles, metals, and sulfur.
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Pinto, Cecilia de Agrela. "The two-component system of a novel copper resistant operon of Marinobacter hydrocarbonoclasticus." Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/10062.
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Dissertation for the Master’s Degree in Structural and Functional BiochemistryThe majority of bacterial heavy metal resistance systems are regulated by twocomponent signal transduction systems. Stimuli from the environment interact with the histidine kinase, which in turn activates the response regulator by phosphorylation. The effector domain of the response regulator then binds to DNA, eliciting the specific response. Analysis of the Marinobacter hydrocarbonoclasticus genome revealed the presence of genes, copXAB, that code for proteins associated with copper response. The biochemical characterization of the two-component signal transduction system, copSR, is of interest due to the vital role it plays in the regulation of expression of the copXAB operon. The genes that encode for the CopR and CopS_C (cytosolic sensor domain of CopS) proteins were heterologously expressed in E.coli and expression was optimized for the production of soluble protein using LB medium. Due to solubility problems, the genes that code for these proteins were cloned as hexahistidine or glutathione S-transferase fusion proteins. CopR and its domains were optimally expressed at 16°C for 16 and 3 h after induction, respectively, whilst CopS_C was expressed at 37°C during 3 h after induction. Proteins were purified using different chromatographic strategies, most of them using affinity chromatography. The yields of pure protein per liter of growth culture obtained after complete purification from the soluble cellular extract were: 0.14 to 0.23 mg/L for CopR; 0.42 mg/L, CopR_NHis6; for the CopR_CHis6 it was 0.16 mg/L and 4.2 mg/L of CopS_C. The molecular mass of each protein was determined by gel filtration, 31 kDa for CopR, 17.5 kDa for CopR_NHis6, 15.1 kDa for CopR_CHis6 and 38.2 kDa for CopS_C. In the case of CopS_C there is the possibility that a dimer is formed, which should be evaluated. From the evaluation of disulfide bonds, using SDS PAGE and PAGE gels, all proteins or protein domains appeared to be monomers when in the presence of β-MEtOH. Circular dichroism evaluated the state of folding of the CopS_C and CopR proteins, which were shown to be folded in which the α-helix structures predominate. A model structure for CopR was also determined which agrees with this analysis. However, in the case of the CopR domains, the data obtained merely indicate folding, due to the low concentrations of the proteins. Phosphorylation and electrophoresis mobility shift assays of the CopR protein were, for the most part, inconclusive. However, in the absence of BSA, formation of the CopR:DNA complex in a gel filtration column is observed, though requires additional evaluation.
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Kim, Seong-Jin. "Directional crystallization in the bismuth-strontium-calcium-copper-oxygen system: Effect of phase separation." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/186040.
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Novel unidirectional crystallization was tested in glasses of the Bi-Sr-Ca-Cu-O system to produce highly oriented microstructures. Some evidence of liquid-liquid phase separations on cooling melts of Bi₂Sr₂Ca₁Cu₂Oₓ and Pb₀ͺ₃₂Bi₁ͺ₆₈Sr₁ͺ₇₅Ca₂Cu₃Oₓ is found for the first time from Differential Thermal Analysis (DTA), X-ray Diffraction (XRD), and Transmission Electron Microscope (TEM). This made it difficult to produce highly oriented microstructures through the present route because one of the phases in the phase separated structure is likely close to "R"-phase composition and lead to copious nucleation of "R"-phase on heating. This also resulted in sequential crystallization of the current liquids, first to "R"-phase and then to the Bi₂Sr₂Ca₁Cu₂Oₓ phase. Theoretical modelling was performed to understand general questions in the present route. The model suggests that a liquid with high interfacial energy is a good candidate for the present route to produce highly oriented microstructures. The model was tested in lithium diborate glass and showed a highly oriented microstructure. Thus, unidirectional crystallization is generally an attractive processing option for a liquid free of phase separation.
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Jensen, Paul William 1967. "A structural and geochemical study of the Sierrita porphyry copper system, Pima County, Arizona." Thesis, The University of Arizona, 1998. http://hdl.handle.net/10150/291456.
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Detailed mapping of the Sierrita-Esperanza orebody has led to a revised interpretation of the Paleocene intrusive units, and a structural model for the emplacement of those units. A left-lateral wrench fault, expressed through Riedel shears, arranged in a flower structure geometry, is proposed to localize the porphyry intrusions, and control mineralization trends. Miocene extensional deformation has not tilted the orebody more than 10°. The San Xavier Thrust is interpreted to be a low angle detachment, upon which the upper plate has moved to the north-northwest approximately 10 km. When the San Xavier "Thrust" ceased movement, a set of low angle normal faults, striking nearly north-south dissected the Sierrita Range. Molybdenite dating, using the Re-Os system, shows that mineralization of the orebody began at 63.5 Ma (±300 ka, 2σ), and ended sometime after 60.0 Ma (±300 ka, 2σ). An isochron of chalcopyrite and pyrite samples with an age of 59.7 Ma (±17.1 Ma, 2σ), and an initial 187Os/188Os of.152 (±0.33, 2σ) suggests that the lower crust beneath the Sierrita Range has a low 187Os/188Os ratio.
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Rushing, Jason Clark. "Advancing the Understanding of Water Distribution System Corrosion: Effects of Chlorine and Aluminum on Copper Pitting, Temperature Gradients on Copper Corrosion, and Silica on Iron Release." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/34235.
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When severe copper pitting problems impacted customers at a large utility, studies were begun to attempt to diagnose the problem and identify potential solutions. A series of tests were conducted to characterize the nature of pitting. Desktop comparisons of pinhole leak frequency and treatment practices at nearly utilities were also documented to identify treatment factors that might be influencing the initiation and propagation of leaks.
Factors identified included the presence of relatively high levels of free chlorine and aluminum in the distribution system. Experiments were conducted to examine the effect of these constituents on copper pitting under stagnant and flow conditions. That led to discovery of a synergistic redox reaction between chlorine, aluminum solids, and copper metal as evidenced by increased chlorine decay rates, non-uniform corrosion, and rising corrosion potentials.
Temperature changes had been suspected to increase copper pitting frequency and copper release to drinking water. Experiments examined the effect of temperature gradients on copper pipe corrosion during stagnant conditions. The pipe orientation in relation to the temperature gradient determined whether convective mixing would occur, which influenced temperature gradients within the pipe. This work is the first to demonstrate that temperature gradients lead to thermogalvanic currents, influences copper leaching and scale type.
Iron release from corroding water mains is another concern of many water utilities, but little is known about chemistry factors that influence the problem. In laboratory experiments, higher levels of silica caused more iron release to the water and decreased the size of suspended iron particles. Silica levels also changed during the experiment: it decreased through incorporation into a dense scale, and increased by release from cast iron during corrosion. Silica slightly decreased iron corrosion rates near the end of this 6-month test.
Master of Science
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Davis, William. "The Effects of Hydrilla Infestation on Selected Wintering Waterfowl: Santee Copper Lake System, South Carolina." TopSCHOLAR®, 1997. http://digitalcommons.wku.edu/theses/773.
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Hydrilla is an exotic aquatic weed that was introduced into Florida in the 1950's. Since that time it has spread rapidly from lake to lake throughout the southeast and beyond. The Santee Cooper lake system in eastern South Carolina was infested with the weed in the early 1980's. Since that time lake managers have sought ways to eliminate the aquatic plant and have succeeded to a great extent through the use of sterile grass carp as a biological control agent. This paper, however, contains evidence to support the view that hydrilla is actually a beneficial habitat for many species on and in the lake. In addition to the perceived positive impact on certain sportfish populations, especially largemouth bass, hydrilla is also a prime habitat for many species of waterfowl that winter on the lake. While traditional wintering species such as Wigeon and Gadwalls have taken advantage of this new source of nutrition and increased greatly in total numbers, Ringneck ducks have multiplied in total numbers during the years of infestation to levels never before seen on this lake. In addition, many species of waterfowl from the diving duck sub group such as Canvasback, Redhead, Scaup, Shoveler, and Bufflehead have been observed on the lake in greater numbers than any time in the recent past. The newfound success in eliminating the hydrilla from the lake, however, did reduce available hydrilla beds drastically over the 1996 - 97 winter migration year, with the existence of the weed in any substantial amounts in question for next year. If the aquatic plant is effectively eliminated from the lake system in coming years, the impact on waterfowl populations will be substantial.
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Farquharson, Colin. "Studies of connective tissue abnormalities in the skeleton and cardiovascular system of copper deficient rats." Thesis, University of Strathclyde, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278277.
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Mäki, J. (Joni). "Lysyl oxidases:cloning and characterization of the fourth and the fifth human lysyl oxidase isoenzymes, and the consequences of a targeted inactivation of the first described lysyl oxidase isoenzyme in mice." Doctoral thesis, University of Oulu, 2002. http://urn.fi/urn:isbn:9514267397.
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Abstract
Lysyl oxidases (EC 1.4.3.13, protein-lysine 6-oxidases) are extracellular copper enzymes that initiate the cross-linking of collagens and elastin by catalyzing oxidative deamination of the ε-amino group in certain lysine and hydroxylysine residues. The cross-links formed are responsible for the tensile strength of collagen fibers and the unique elastic properties of elastin.
Three human lysyl oxidase isoenzymes, lysyl oxidase (LOX), lysyl oxidase-like protein (LOXL), and lysyl oxidase-like 2 protein (LOXL2), have been identified and characterized so far. Two additional human lysyl oxidase isoenzymes, lysyl oxidase-like 3 (LOXL3) and lysyl oxidase-like 4 (LOXL4), proteins were identified, cloned, and partially characterized in this study. Both polypeptides showed a high degree of overall similarity to each other and to the LOXL2 polypeptide, whereas the two polypeptides showed a significant similarity to LOX and LOXL only in the C-terminal region, which contains all amino acid residues thought to be needed for the catalytic activity of the LOX enzyme. The LOXL3 gene is expressed in several tissues, the highest expression levels being in the placenta, heart, ovary, testis, small intestine, and spleen. The LOXL4 gene is likewise expressed in most human tissues studied, the highest levels being seen in the skeletal muscle, testis, and pancreas. Both polypeptides were shown to be secreted extracellular proteins.
The role of the first described LOX isoenzyme was studied by inactivating its gene in mice. Most Lox-/-
embryos died at the end of gestation, and the few live-born pups were cyanotic and died within a few hours, autopsy revealing large aortic aneurysms. Light microscopy demonstrated structural abnormalities in the aortic walls of Lox-/- embryos, and further analysis by electron microscopy showed highly fragmented elastic fibers, discontinuity in the smooth muscle cell layers, and endothelial cell damage. Doppler ultrasonography of Lox-/- embryos in utero revealed multiple signs of cardiovascular dysfunction, which contributed to the early death of the Lox-/- mice. The results indicate that Lox has an essential role in the development and function of the cardiovascular system and that this role cannot be replaced to any significant extent by other lysyl oxidase isoenzymes.
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Xiao, Weizhong. "EFFECT OF SOURCE WATER BLENDING ON COPPER RELEASE IN PIPE DISTRIBUTION SYSTEM: THERMODYNAMIC AND EMPIRICAL MODELS." Doctoral diss., University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4409.
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This dissertation focuses on copper release in drinking water. Qualitative and quantitative assessment of Cu and Fe corrosion by process water quality was assessed over one year in a field study using finished waters produced from seven different treatment process and eighteen pilot distribution systems (PDSs) that were made from unlined cast iron and galvanized steel pipes, and lined cement and PVC pipes taken from actual distribution systems. Totally seven different waters were studied, which consisted of three source waters: groundwater, surface, and simulated brackish water designated as G1, S1, and RO. With certain pre-established blending ratios, these three waters were blended to form another three waters designated as G2, G3, and G4. Enhanced surface water treatment was CFS, ozonation and GAC filtration, which was designated as S1. The CFS surface water was nanofiltered, which is S2. All seven finished waters were stabilized and chloraminated before entering the PDSs. Corrosion potential was compared qualitatively and quantitatively for all seven waters by monitoring copper and iron release from the PDSs. This dissertation consists of four major parts. (1) Copper corrosion surface characterization in which the solid corrosion products formed in certain period of exposure to drinking water were tried to be identified with kinds of surface techniques. Surface characterization indicated that major corrosion products consists of cuprite (Cu2O) as major underneath corrosion layer and tenorite (CuO), cupric hydroxide (Cu(OH)2) on the top surface. In terms of dissolution/precipitation mechanism controlling the copper concentration in bulk solution, cupric hydroxide thermodynamic model was developed. (2) Theoretical thermodynamic models were developed to predict the copper release level quantitatively based on controlling solid phases identified in part (1). These models are compared to actual data and relative assessment is made of controlling solid phases. (3) Non-linear and linear regression models were developed that accommodated the release to total copper for varying water quality. These models were verified using independent data and provide proactive means of assessing and controlling copper release in a varying water quality environment. (4) Simulation of total copper release was conducted using all possible combinations of water quality produced by blending finished waters from ground, surface and saline sources, which involves the comparison of copper corrosion potentials among reverse osmosis, nanofiltration, enhanced coagulation, lime softening, and conventional drinking water treatment.Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil and Environmental Engineering
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Mathur, Aditi. "Optimization of Polymer Enhanced Diafiltration system by studying copper removal from aqueous solutions using Lambda-carrageenan." Digital WPI, 2008. https://digitalcommons.wpi.edu/etd-theses/993.
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"Excessive discharge of heavy metals has been one of the major causes of water pollution worldwide. Various traditional methods of heavy metal removal have been devised but certain drawbacks like high cost, high energy requirement, and the production of toxic sludge have limited their use. Hence, biosorption is one of the alternative methodologies. This study combined biosorption and diafiltration in an attempt to optimize Polymer Enhanced Diafiltration to study copper removal from aqueous solutions by the use of a biopolymer, lambda-carrageenan. Lambda-carrageenan was studied as a biosorbent owing to properties such as low cost, good water solubility, non-gelling nature and the presence of sulfate groups which can sequester cations. Conditions for binding such as pH, temperature and concentration of copper and lambda-carrageenan were studied. Equilibrium dialysis experiments were performed to study the metal ion membrane transport kinetics and to determine the metal ion binding capacity and strength of the copper-biopolymer association. Rheological measurements were performed to determine how the viscosity of lambda-carrageenan changes with increase in shear stress and with increase in metal concentration. The solution was found to be shear thinning. However, with increase in metal concentration, viscosity was found to increase when high concentrations of polymer (8 g/L and 12 g/L) were used. Solution viscosity was found to decrease with increase in metal concentration when 4 g/L of polymer was used. Polymer Enhanced Diafiltration studies showed no leakage of the polymer through the membrane and no significant binding elsewhere in the PEDF system. It also showed an impressive retention of copper inspite of a rather high metal ion-polymer dissociation constant suggesting a yet not understood series of events occurring on the membrane of the PEDF system. Lambda-carrageenan is a linear polysaccharide, which might be stacking up on the membrane after forming layers, and not allowing any free metal ion to escape. Other reasons could be the sieving effect, degradation of the polymer due to shear and compaction of molecule on metal binding such that the polymer is not itself escaping through the membrane, but also not allowing the free metal ion to escape. Hence, this study suggests the need for more information on the metal-polymer interactions on the surface of the membrane by designing a direct observation experiment with a mini-tangential flow filtration system."
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Beamguard, Miles B. "Mathematical model of arsenic adsorption in a modified zeolite / Microfiltration System." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001804.
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Affandi, Trisiani, and Trisiani Affandi. "Structural and Functional Characterization of the Histidine Kinase CusS in Escherichia coli." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/622937.
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Bacteria may live in harsh environments where they face changing and new conditions. Therefore, the ability to maintain homeostasis in cells may be vital for survival. Transition metals such as iron, zinc, and copper are essential nutrients for cell survival, but become toxic if in excess amount. In order to survive, bacteria have developed defensive mechanisms to protect themselves. Copper and silver levels need to be carefully maintained within cells to balance cellular needs with potential toxicity. This dissertation focuses on the Cus copper and silver efflux system in E. coli. The E. coli cus system is composed of two divergently transcribed operons, cusCFBA and cusRS. The cusCFBA genes encode for a tripartite metal efflux pump CusCBA and a metallochaperone CusF. The cusRS genes encode a two-component system CusS-CusR that regulates the expression of the cusCFBA genes in response to elevated levels of copper or silver in the periplasm. The histidine kinase CusS senses and binds to metals on its periplasmic sensor domain and transduces signal into the cytoplasm to further communicate with its cognate response regulator CusR through histidyl-aspartyl phosphotransfer event. CusR then outputs cellular response by activating the upregulation of the cusCFBA genes, which then turn on the CusCBA efflux pump to eliminate excess copper or silver in the periplasm. While bacterial two-component systems have been widely studied, the mechanisms of ligand-induced signal transduction by histidine kinases remain unclear. It is now known that cusS is essential for copper and silver resistance, and CusS directly binds metal ions in the periplasmic sensor domain and dimerizes upon metal binding. Thus, the goal of this research is to characterize the metal binding properties in the sensor domain, and to elucidate the signal transduction and autophosphorylation mechanisms of CusS upon metal binding. The data from this work reveal that there are two distinct metal binding sites, interface and internal binding sites, in the sensor domain of CusS, and the interface binding site is functionally more important in metal resistance in E. coli. Furthermore, metal-induced dimerization through the interface metal binding site plays an important role in CusS kinase activity. Together, these findings aid in our understanding of the molecular details in metal binding within the sensor domain of CusS. Based on these data, we propose a model for the signal transduction mechanism and histidine phosphorylation mechanism of the histidine kinase CusS.
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Rusk, Brian Geoffrey. "Cathodoluminescent quartz textures and fluid inclusions in veins of the porphyry copper-molybdenum deposit in Butte, Montana : constraints on physical and chemical evolution of the hydrothermal system /." view abstract or download file of text, 2003. http://wwwlib.umi.com/cr/uoregon/fullcit?p3080595.
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Thesis (Ph. D.)--University of Oregon, 2003.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 211-235). Also available for download via the World Wide Web; free to University of Oregon users.
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El, Mallah Nadine Hassan. "Dispersion of the carbon nonotubes in a vacuum arc system and synthesis of copper-carbon nanotubes composites." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99408.
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Electric arcs operating in the thermo-field mode are used in many industrial processes. They are used in electricity transport and distribution, in metal production industry, and in plasma processing applications like in plasma spraying and as the plasma source in physical vapour deposition (PVD) processes. The electric arc-based systems have the common problem of material degradation at the attachment point of the electric arc on the electrode, mainly the cathode surface. The cathode erosion is particularly severe in higher power devices such as plasma torches and circuit breakers. The cathode erodes while producing the ions needed for the electric discharge to occur. Cathode erosion is one big limitation to the use of electric arcs in industry. Carbon nanotubes (CNTs) are 1-D structures with a diameter in the nanoscale range giving them very good field emission properties. These properties make them possible candidates to form metal-CNT composites that can be used as electrodes. The CNTs presence at the electrode surface may help in providing an enhanced electron emission and reduced erosion. The long term objective of this project is to form a new class of electrode materials, namely copper-CNT nanocomposites. One major problem of using these CNTs in composites is their agglomeration and inability to disperse easily. In this project, a pulsed arc discharge system is used to study the capability to ablate, disperse, transport, and deposit the CNTs onto a substrate. The project involves studying the ability to form a nanocomposite made of copper and CNTs from a target and deposition of the copper-CNT mixture on a substrate.
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Sadagopan, Rishi S. "Effect of copper and nickel on the performance of an activated sludge system treating cellulose acetate wastewater." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-09292009-020122/.
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Heinrich, Glen Sean. "An investigation into the use of froth colour as sensor for metallurgical grade in a copper system." Master's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/15427.
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Bibliography: leaves 91-92.In recent years the development of Machine Vision systems has opened up new possibilities for non-intrusive process performance sensors and process control. There are currently various Machine Vision systems on notation plants worldwide (Metso at Kennecott, Frothcam at Escondida). Extensive research has been done on using froth image analysis in closed loop control (Hyotyniemi et aI, 2000; Kittel et aI, 2001; Holtham and Nguyen, 2002; Cipriano et aI, 1998) and recently plants have been using these systems to control the air or level of a flotation cell as a means of controlling mass pull using the froth velocity output. As yet no flotation plants have reported the use of froth colour in their control strategies, however it is well accepted that an experienced operator can judge the metallurgical state of a flotation cell by the appearance of the froth, using colour as a key descriptor of grade, particularly in the case of copper froths. For this reason an investigation was undertaken to evaluate whether a relationship existed between concentrate grade and the froth colour obtained using a Machine Vision system. This relationship could be used to control reagent addition or for system diagnostics. Both would be invaluable tools for the flotation industry. A Machine Vision system called SmartFroth has been developed at University of Cape Town (VCT) as a research tool to investigate the relationships between froth surface indicators and metallurgical parameters. The relationship between froth colour and % solids was also investigated as it was believed that solids loading could be reflected by froth colour. This work was aimed at evaluating the empirical relationship between froth colour and copper grade in the laboratory and then investigating whether a similar relationship existed on plant. Various colour spaces were examined to find one appropriate for the copper flotation froths in order to allow for accurate colour analysis. It also evaluated the use of calibration objects in the colour analysis of flotation froths. This work also evaluated relating froth colour to % solids on plant. Two batch flotation campaigns were done using different ores as well as a preliminary plant trial.
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Morard, Adrien. "Miniaturisation et fiabilité des interconnexions copper pillar sur desassemblages de type « System In Package » (sip) pour le domaine aéronautique." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT068.
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La thèse s’inscrit dans un contexte d’ouverture vers de nouvelles solutions techniques. L’objectif quiest porté par cette étude est double, le premier est de miniaturiser l’électronique pour atteindre un gaind’un facteur 10 en intégration par rapport à une technologie CMS classique, le second est d’améliorer lafiabilité des assemblages de type « System In Package » ainsi obtenus pour les domaines aéronautique,défense et spatial.La première phase de travail concerne la fabrication d’un assemblage composé d’une puce en siliciumet d’un substrat organique. Ces deux entités permettront l’étude du report par flip chip. Pour ce faire, desconnexions de type micro-piliers en cuivre et en alliage étain-argent, autrement appelées « copper pillar »seront mises en place. L’impact des différents paramètres de conception et d’assemblage sur la fiabilité encycles thermiques seront étudiés.Dans une seconde phase, des simulations par éléments finis sont effectuées sur les assemblages afind’obtenir des prédictions sur la fiabilité au cours de cycles thermiques en utilisant comme critère l’énergieviscoplastique. Les simulations et les résultats expérimentaux seront finalement comparés et les écartsseront discutés.L’analyse de défaillances au cours des cycles thermiques reposera sur l’analyse des interconnexions« copper pillar » par micro-sections et imagerie SEM et EBSD. Les évolutions d’épaisseur d’intermétalliques,des fissurations dans la brasure ainsi que la taille des grains et les phénomènes de recristallisation serontprésentés et commentés.Les objectifs finaux de ce travail sont, d‘un point de vue académique, de mettre en lumière toutd’abord, les comportements mis en jeu dans la fiabilité de telles interconnexions dans un environnementthermo-mécanique contraignant, et, par ailleurs, les mécanismes de défaillance. Ensuite, il s’agit d’établirun modèle de vieillissement qui soit représentatif des résultats expérimentaux obtenus. Enfin, il s’agira dedéfinir des règles de conception qui pourront ensuite être utilisées au niveau de Safran pour la réalisationdes assemblages SIP intégrés dans des systèmes embarquésThe thesis is opening towards new technical solutions. The aim of this study is twofold, the first is tominiaturize the electronics to achieve a factor of 10 in integration compared to a conventional CMStechnology, the second is to improve the system in package reliability for aeronautics, defense and space.The first step concerns the manufacture of an assembly composed by a silicon chip and an organicsubstrate. These two entities will allow the study of the report by flip chip. To do so, micro-pillar type copperand tin-silver solder connections, otherwise known as copper pillar, will be used. The impact of differentdesign and assembly parameters on thermal cycles reliability will be studied.In a second step, finite element simulations are carried out on the assemblies in order to obtainpredictions on the reliability during thermal cycles using as a criterion the viscoplastic energy. Thesimulations and the experimental results will eventually be compared, and the gaps will be discussed.Failures analysis during thermal cycles will be based on the analysis of copper pillar interconnectionsby micro-sections and SEM and EBSD imaging. Thickness changing in intermetallic, cracking in the solder aswell as grain size and recrystallization phenomena will be presented and commented.The final objectives of this work are, from an academic point of view, to highlight first of all, theC2 - Restrictedbehaviors involved in the reliability of such interconnections in a binding thermo-mechanical environment,and moreover, the failure mechanisms. Then, it is to establish a predict life model that is representative ofthe experimental results obtained. Finally, it will define design rules that can then be used at Safran for therealization of SIP
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Muraco, Cory E. "Isolation and Characterization of Oxidized Lysozyme Variants Produced by a Copper(II)/Hydrogen Peroxide Metal-Catalyzed Oxidation System." Youngstown State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1369228839.
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Edwards, Sion Charles. "The behaviour of mercury and copper contamination in a lowland river system and their accumulation by some biota." Thesis, Imperial College London, 1995. http://hdl.handle.net/10044/1/7457.
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Sunyer, i. Borrell Alba. "Arsenic inertization through alunite-type phases: Application to copper pyrometallurgy." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/128666.
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Nowadays, arsenic is an important problem in water pollution. Non-ferrous metallurgical industries generate arsenic residues because the ores contain this mineral. The high technology improvement is increasing the demand of some metals such as copper. This increasing demand and the scarce of copper ores with low arsenic content is generating a problem with arsenic wastes in lots of countries, but especially in Asia and in South and Central America. In these countries, groundwater is polluted by arsenic and generates health problems to the inhabitants. With the aim to precipitate and control the arsenic generated by these industries, different methods has been studied: Calcium arsenate, ferrihydrite and scorodite. The former is just a precipitation method with a very low arsenate stability. On the other hand, ferrihydrite and scorodite pass the TCLP from different countries, however, the long-term stability is not satisfactory, and many studies indicate that these phases easily decompose in long-term storage producing arsenic release. Moreover, these are iron-phases, that’s mean that not only the arsenic release can also be easily produced in reductive conditions.
With the aim to found a phase with a good stability in long term, this thesis proposes the arsenic inertization through alunite-type phases, concretely with aluminum in the structure. Aluminum was chosen instead of iron because its good properties in reductive environments, which make it very difficult to be reduced. These phases has the characteristic to be able to substituted part of the sulfate present in the structure by arsenate. This substitution is the one studied in natroalunites, alunites and hydroniumalunites, as well as in analogous members. The incorporation of arsenate is possible in natroalunites and alunites members with the same partition: (AsO4/(SO4+AsO4))S ≅ 0.5(AsO4/(SO4+AsO4))L. With the arsenate incorporation in the natroalunite/alunite structure, the c cell parameter increased with a slope of ~0.58 Å. However, a higher initial c cell parameter does not have any effect in the arsenate incorporation in the structure. Other alunite-type phases such as hydronium-alunite, barium-alunite and leadalunite were also investigated with different results. Hydronium-alunite was formed under the same conditions of alunite and natroalunite. However, with the addition of arsenic in the medium this phase formation decreased, and arsenic was practically not incorporated in the structure. Barium-alunite and lead-alunite syntheses were performed from barium and lead sulfates respectively. However, the insolubility of its sulfates
made not possible the syntheses of these alunites, instead, hydronium alunites were precipitated with barium or lead sulfate, and depending on the arsenic concentration with mansfieldite. Arsenical natroalunites were also performed with real wastes from copper pyrometallurgical plants. These arsenical natroalunites give the same results as the synthetic, with the same incorporation of arsenate and the same c cell parameter increase. Short, medium and long-term stability tests were performed in all synthesized natroalunites, in some arsenical alunites and in scorodites (synthetic and natural).
Arsenical natroalunites and arsenical alunites gave good results in short-term tests (0.01-0.03 mg As/L). In long-term tests (up to 6 months) were done in natroalunites. These tests also gave a great stability of arsenical natroalunite, which were stabilized at 0.1 mg As/L. Medium-term tests (up to 5 weeks) were performed in arsenical alunites and scorodites (natural and synthetic). Arsenical alunites were stabilized at 0.3 mg As/L, similar values were obtained for natural scorodite (0.4 mg As/L). Whereas synthetic scorodite presented higher values (1.3 mg As/L) than arsenical natroalunites and arsenical alunites, indicating less stability in the same conditions.Avui en dia l’arsènic és un problema de contaminació de les aigües important. Una de les fonts de generació de residus amb arsènic són les indústries metal•lúrgiques no ferroses. En la metal•lúrgia del coure, la important demanda d’aquest metall està obligant a obtenir el coure de menes que cada cop contenen més arsènic. Així doncs, cada cop es generen més residus amb arsènic que han de ser abocats a llocs controlats. En alguns països, aquests residus estan provocant problemes de contaminació a les aigües freàtiques. Per tal d’evitar aquests problemes, s’han fet nombrosos estudis per a la precipitació i estabilització de l’arsènic. Malgrat tot, totes les fases estudiades contenen ferro, que és pot reduir fàcilment en sòls reductors. A més a més, molts estudis indiquen que totes aquestes fases, a llarg termini s’acaben descomponent permetent la dissolució de l’arsènic que contenen. Amb la intenció de trobar una solució a aquest problema, en aquesta tesi es proposa la inertització d’arsènic a través de fases del supergrup de l’alunita, concretament les que porten alumini i no ferro en l’estructura. Aquestes fases presenten la característica de poder substituir part del sulfat de l’estructura per arseniat. Aquesta substitució és la que s’ha estudiat en natroalunites, alunites i hidroni alunites, així com en d’altres membres anàlegs. La incorporació d’arseniat ha estat possible en natroalunites i alunites, seguint la mateixa partició: (AsO4/(SO4+AsO4))S ≅ 0.5(AsO4/(SO4+AsO4))L. Amb la incorporació d’arseniat el paràmetre de cel•la c s’incrementava amb una pendent de ~0.58 Å. No obstant, un paràmetre de cel•la c inicial de l’alunita més gran, no té efecte en la incorporació d’arseniat a l’estructura. Finalment, l’estabilitat a curt, a mig i a llarg termini de les natroalunites i les alunites ha resultat sé molt bona. A curt termini aquesta era de 0.01-0.03 mg As/L a pH’s entre 5 i 8. A llarg termini (6 mesos) la natroalunita es va estabilitzar a 0.1 mg/L. En tests a mig termini (5 setmanes) l’alunita es va estabilitzar a 0.3 mg As/L. Aquests valors de dissolució són molt més bons que en d’altres fases utilitzades, com per exemple les escorodites, les quals presenten un valors a curt termini un ordre de magnitud més elevats. A mig termini es va veure que l’escorodita natural presenta un valor similar al de l’alunita (0.4 mg/L), mentre que l’escorodita sintètica presenta un valor de 1.3 mg/L, molt més elevat que els obtinguts per alunites i per natroalunites.
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MacNevin, David. "THE EFFECTS OF PHOSPHATE AND SILICATE INHIBITORS ON SURFACE ROUGHNESS AND COPPER RELEASE IN WATER DISTRIBUTION SYSTEMS." Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3713.
Full textAbstract:
The effects of corrosion inhibitors on water quality and the distribution system were studied. This dissertation investigates the effect of inhibitors on iron surface roughness, copper surface roughness, and copper release. Corrosion inhibitors included blended poly/ortho phosphate, sodium orthophosphate, zinc orthophosphate, and sodium silicate. These inhibitors were added to a blend of surface water, groundwater, and desalinated brackish water. Surface roughness of galvanized iron, unlined cast iron, lined cast iron, and polyvinyl chloride was measured using pipe coupons exposed for three months. Roughness of each pipe coupon was measured with an optical surface profiler before and after exposure to inhibitors. For most materials, inhibitor did not have a significant effect on surface roughness; instead, the most significant factor determining the final surface roughness was the initial surface roughness. Coupons with low initial surface roughness tended to have an increase in surface roughness during exposure, and vice versa, implying that surface roughness tended to regress towards an average or equilibrium value. For unlined cast iron, increased alkalinity and increased temperature tended to correspond with increases in surface roughness. Unlined cast iron coupons receiving phosphate inhibitors were more likely to have a significant change in surface roughness, suggesting that phosphate inhibitors affect stability of iron pipe scales. Similar roughness data collected with new copper coupons showed that elevated orthophosphate, alkalinity, and temperature were all factors associated with increased copper surface roughness. The greatest increases in surface roughness were observed with copper coupons receiving phosphate inhibitors. Smaller increases were observed with copper coupons receiving silicate inhibitor or no inhibitor. With phosphate inhibitors, elevated temperature and alkalinity were associated with larger increases in surface roughness and blue-green copper (II) scales.. Otherwise a compact, dull red copper (I) scale was observed. These data suggest that phosphate inhibitor addition corresponds with changes in surface morphology, and surface composition, including the oxidation state of copper solids. The effects of corrosion inhibitors on copper surface chemistry and cuprosolvency were investigated. Most copper scales had X-ray photoelectron spectroscopy binding energies consistent with a mixture of Cu2O, CuO, Cu(OH)2, and other copper (II) salts. Orthophosphate and silica were detected on copper surfaces exposed to each inhibitor. All phosphate and silicate inhibitors reduced copper release relative to the no inhibitor treatments, keeping total copper below the 1.3 mg/L MCLG for all water quality blends. All three kinds of phosphate inhibitors, when added at 1 mg/L as P, corresponded with a 60% reduction in copper release relative to the no inhibitor control. On average, this percent reduction was consistent across varying water quality conditions in all four phases. Similarly when silicate inhibitor was added at 6 mg/L as SiO2, this corresponded with a 25-40% reduction in copper release relative to the no inhibitor control. Hence, on average, for the given inhibitors and doses, phosphate inhibitors provided more predictable control of copper release across changing water quality conditions. A plot of cupric ion concentration versus orthophosphate concentration showed a decrease in copper release consistent with mechanistic control by either cupric phosphate solubility or a diffusion limiting phosphate film. Thermodynamic models were developed to identify feasible controlling solids. For the no inhibitor treatment, Cu(OH)2 provided the closest prediction of copper release. With phosphate inhibitors both Cu(OH)2 and Cu(PO4)·2H2O models provided plausible predictions. Similarly, with silicate inhibitor, the Cu(OH)2 and CuSiO3·H2O models provided plausible predictions.Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engineering PhD
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Bashir, Muhammad Muqarrab. "Modeling reliability in copper/low-k interconnects and variability in cmos." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41092.
Full textAbstract:
The impact of physical design characteristics on backend dielectric reliability was modeled. The impact of different interconnect geometries on backend low-k time dependent dielectric breakdown was reported and modeled. Physical design parameters that are crucial to backend dielectric reliability were identified. A methodology was proposed for determining chip reliability but combining the insights gathered by modeling the impact of physical design on backend dielectric breakdown.
A methodology to model variation in device parameters and characteristics was proposed. New methods of electrical and physical parameter extraction were proposed. Models that consider systematic and random source of variation in electrical and physical parameters of CMOS devices were proposed, to aid in circuit design and timing analysis.
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Thompson, Denis Alan. "Removal of copper and nickel from solution by the non-viable biomass of the water fern Azolla filiculoides in an upscaled fixed-bed column system." Thesis, Rhodes University, 2001. http://hdl.handle.net/10962/d1003973.
Full textAbstract:
The potential of non-viable Azalia filiculaides for the removal of Cu and Ni from aqueous solutions and the possibility of scaling up existing lab scale Azalia column systems was investigated. The effects of factors such as metal starting concentration, pH and two metals in solution on the removal of Ni and Cu from aqueous solution by dried and crushed Azalia biomass were studied in batch systems. Aqueous solutions of Ni with starting concentrations between 1000 and 2000J.lmolll gave the most efficient Ni removal by Azalla biomass. For Cu the optimum starting concentration for adsorption was 50J.lmol/l. The adsorption capacity of both eu and Ni increased as the starting pH of the sorption media increased. The optimum pH for Ni adsorption was found at pH 7 and for Cu, at pH 5. - Awlla biomass had a higher. maximum binding capacity (qrnax) for Cu than for Ni at pH 5. The removal of both Cu allct Ni showed little or no variation with the presence another metal in solution. Kinetic studies show that both Cu and Ni adsorbed rapidly onto the Azalia biomass. The removal of Cu and Ni from aqueous solutions using non-viable Azalia biomass was investigated in a lab scale fixed-bed column and an upscaled 4L column system. The nonviable Azalla filiculaides biomass when dried and used in a column for adsorption of Cu and Ni showed good physical stability under many different conditions. Preparation of the biomass before it could be used in the columns was very simple and did not involve any significant pretreatment steps. Prolonged exposure to UV light decreases Azalia biomass capacity for Ni and Cu adsorption. Column adsorption of Cu and Ni from aqueous solutions was successfully upscaled approximately 100 times. Relative to the lab scale column, the 4L column performed better for the uptake of Cu and Ni per gram of biomass. The larger column was also able to operate at relatively higher flow rates. The biomass showed good reusability with little change in the amount of Ni adsorbed in 10 consecutive cycles. Electron micrographs showecf little or no change in the physical structure and integrity of the Azolla biomass after exposure to mineral acids, Ni solution and high flow rates over 10 consecutive adsorption and desorption cycles. As much as 80% Ni and 70 % Cu was recovered when desorption profiles were generated using O.lMHCI as a desorption agent. The 4L column system was also tested using a highly concen~rat:~ Ni plating bath solution.(Nicrolyte 1). Only 18 % of the Ni could be removed from the expended Nicrolyte 1 pla~Jng solution after treating only 25L, indicating that Azolla biomass is more suited for removal of metals from more dilute industrial effluents.
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Farooqi, Owais Ehtisham. "An Assessment and Modeling of Copper Plumbing pipe Failures due to Pinhole Leaks." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/33918.
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Pinhole leaks in copper plumbing pipes are a big concern for the homeowners. The problem is spread across the nation and remains a threat to plumbing systems of all ages. Due to the absence of a single acceptable mechanistic theory no preventive measure is available to date. Most of the present mechanistic theories are based on analysis of failed pipe samples however an objective comparison with other pipes that did not fail is seldom made. The variability in hydraulic and water quality parameters has made the problem complex and unquantifiable in terms of plumbing susceptibility to pinhole leaks.
The present work determines the spatial and temporal spread of pinhole leaks across United States. The hotspot communities are identified based on repair histories and surveys. An assessment of variability in water quality is presented based on nationwide water quality data. A synthesis of causal factors is presented and a scoring system for copper pitting is developed using goal programming. A probabilistic model is presented to evaluate optimal replacement time for plumbing systems. Methodologies for mechanistic modeling based on corrosion thermodynamics and kinetics are presented.Master of Science
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Xiao, Zhifeng 1966. "Experimental and theoretical studies of the solubility of copper in liquid and vapor in the system NaC1-HC1-HO." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36733.
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Copper solubility in water vapor and liquid was measured in the HCl-NaCl-H 2O system at temperatures up to 400°C and vapor-saturated pressure by two series of experiments. The thermodynamic data from these experiments were then applied to model the genesis of volcanogenic massive sulfide deposits and the partitioning of copper between vapor and liquid.The solubility of copper in liquid was measured in vapor-saturated aqueous HCl/NaCl solutions at temperatures ranging from 40 to 300°C, total chloride concentrations from 0.01 to 1 m, and pH from 0 to 3.5. Copper was found to dissolve primarily as CuCl(aq), CuCl2- and CuCl32-. Data collected from the experiments were regressed to determine the equilibrium constants as functions of temperature (K): Cu(s) + 1/4O2(g) + H+ + xCl- = CuClx1-x +1/2 H2O(l), where x varied from 1 to 3.
Data obtained on the solubility of copper in the liquid phase were used to model gold-copper and gold-zinc mineralization in VMS deposits. Equilibrium path calculations, employing EQ3/6, predict temperatures of precipitation, the paragenetic sequence of minerals, and the chemical composition of chimneys associated with vents on the seafloor at 21°N, East Pacific Rise. The modeling results suggest that the co-precipitation of gold with copper and zinc at different temperatures is determined by the behavior of their complexes in the solution. However, among the models simulated, only the conductive cooling model and combined mixing and cooling model predict the co-precipitation of gold and copper at high temperature (>300°C) and gold-zinc at low temperature (<250°C), which is common in VMS deposits.
The solubility of CuCl(s) in the vapor was measured in a vapor-saturated H2O(I)-H2O(v)-NaCl-HCl (NaCl/HCl; 9:1) system at temperatures ranging from 360 to 400°C, and total chloride concentration from 0.01 to 5 m. At 360°C, the copper solubility can be described by the reaction: CuCl(s) + H2O(v) = CuCl⁺H2O(v), and the equilibrium relationship for this reaction by KC = mCuCl⁺H2Ov /rH2Ov , where mCuCl⁺H2Ov is the molality of copper in the vapor phase and rH2Ov is the density of water vapor; the log KC value is ~-2.01. At 380°C and 400°C, copper solubility is controlled by the reaction: CuCl(s) + 4 H2O(v) = CuCl ⁺ 4H 2O(v). The equilibrium relationship for this reaction is KC = mCuCl⁺4H2O v/r4 H2Ov , and the values of log KC values are 0.22 and 1.17 at 380 and 400°C, respectively.
Partition coefficients for copper between vapor and liquid were calculated for the CuCl-NaCl-HCl-H2O(l)-H2O(v) system at the following conditions, where T = 400°C, P = water vapor saturated pressure, mNaCl = 0.5--2.3m, and mHCl = 0.001 m. The close similiarity of the partition coefficients for copper to those of sodium under the same conditions suggests that partitioning data for NaCl can be used to estimate copper (I) chloride partition coefficients at conditions for which no data are available.
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張曉筑. "Add Thiourea for Acidic Copper System." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/18954122324851127846.
Full textAbstract:
碩士明新科技大學
化學工程與材料科技研究所
100
There were different kinds of additives used in the process of electroplating copper. The experiment focused on the effect of the electroplating procedure of copper by changing the thiourea concentration, observing the structure of the surface, rate of metal deposition, analysis of crystal structure and the change of resistivity with the equipments of SEM, EDS, XRD and four-point prove. The reason to use additives was to improve the roughness, smoothness and sameness of the coating. The acid sulfuric acid copper was the main electroplating solution due to it’s simple composition, stability, high current rate and high efficiency. The results showed that when the additive of sulfur urea was at 10 ppm, the structure of the specimen was denser, the coating smoother, the deposition faster, resistivity higher and so on.
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CHENG, CHUNG-HAO, and 鄭中豪. "Development of Automatic Copper Wire Elongation System." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/br2syh.
Full textAbstract:
碩士國立勤益科技大學
電子工程系
107
Copper wire is currently a most widely used conductive material for transmitting various signals. Its size can be produced as small as 0.01mm, particularly in medical health equipment. Although most of the wire elongation process has been atomized, it still requires human to thread the wire through tens of die molds in advance, usually taking tens of minutes. To resolve this problem, this paper develops an automatic mechanical control system for wire elongation. The proposed hardware system mainly contain three pneumatic claws that can replace the human hands operation are designed in the proposed system. The first claw is used to clamp the wire. The second claw fixed in the rotating mechanism is to draw the heated wire. The third claw is used to move the wire going through the die molds. The wire drawing power is generated from the gear connection controlled by the serer motor. The control software is developed by PLC programming. The experimental results confirm that the proposed can work efficiently in terms of robust and rapid performance.
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Bolcavage, Ann. "A study of the copper-indium binary system." 1991. http://catalog.hathitrust.org/api/volumes/oclc/24334235.html.
Full textAbstract:
Thesis (M.S.)--University of Wisconsin--Madison, 1991.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 67-68).
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Tsai, Wen-Ching, and 蔡文慶. "High Frequency Pulse Plating in Acid Copper System." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/94402318544442499309.
Full textAbstract:
博士國立清華大學
化學工程學系
91
In this dissertation, the effects of high frequency pulse plating on copper deposition in acid copper system were theoretically and experimentally studied. In the part of theoretical analysis, numerical simulations were employed to predict the influence of additive with various inclusion rates and capacities on potential response and mass transfer. The analyses of potential responses at various pulse periods were employed to account for the variation of current efficiency by pulse current. In the experimental analysis, copper electrodeposition in plated-through-hole (PTH) process and onto copper seed layer over silicon wafer by high frequency pulse current (PC) and pulse-reverse current (PR) were characterized by linear sweep voltammetry (LSV), cyclic voltammogram (CV), impedance, scanning electron microscopy (SEM) and x-ray diffraction (XRD). 80 ppm chloride ions (Cl-), 100 ppm polyethylene glycol (PEG) with 4000 average molecular weight and 40 ppm 3-mercapto-1-propanesulfonate (MPS) were used as additives and compared with the baths without additives. In the absence of additives, capacitive current density can be neglected owing to the smaller overpotential. However, the double layer effect can not be neglected in the millisecond range pulse plating in the presence of additives. Overpotential response is strongly affected by the presence of additives. Capacitive current density not only increases in the presence of additives due to increase in overpotential but also increases with increasing capacity of double layer. Then, the variation of surface concentrations of additives and metal ions diminishes as a result of the fast charging and discharging of the double layer. This prediction is consistent with the experimental overpotential response on a copper rotating disk electrode in a bath with and without 100 ppm PEG. The current efficiency of copper deposition decreases with shortening pulses in the millisecond range but increases with shortening pulses in the microsecond range. Shortening the pulse period could change the rate-determining step from the first-step charge transfer and surface diffusion to the first-step charge transfer. Only in the millisecond range, the current efficiency decreases with shortening pulse period due to the disproportionation of cuprous ions and the dissolution of copper adatom. However, in the microsecond range, the current efficiency was found to increase with decreasing pulse period because the adatoms are directly incorporated into steps and kink sites, and the disproportionation of cuprous ions or the dissolution of copper adatoms has less chance to occur. High frequency PC and PR can improve the deposition uniformity in PTH. In an additive-free electrolyte, the deposition uniformity in PTH with high frequency PC and PR at 20 mA/cm2 average current density is better than that with low frequency PC and PR. Based on impedance analysis, plating at low frequency is controlled by the diffusion of cuprous or cupric ion while plating at high frequency is controlled by charge transfer. Changing the rate-determining step from diffusion control to charge transfer control results in an improved metal distribution. In the presence of additives (PEG+MPS+Cl), the uniformity improves with DC at 20 or 10mA/cm2. The trend in the baths with additives using PC and PR at high and low frequency is similar to that in the bath without additives. However, the improvement by high frequency PC and PR is not significant since the plating is under adsorption control. The resistivity of copper deposit decreases with increasing PC and PR frequency in the baths with and without additives. The deposit becomes smoother with larger grain size as the frequency increases. Since overpotential decreases with increasing pulse frequency, it results in lower resistivity. In addition, the increase in the fraction of (200) at high frequency also reduces the resistivity. In the presence of additives, the copper resistivity of a bath with additives is generally lower than that without additives. A larger grain size can be obtained in the presence of additives because the additives tend to decrease overpotential, which naturally lead to lower resistivity.
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楊世權. "Research of Fabrication Copper Nanofluid by Plasma Arc System." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/13634383109450458847.
Full textAbstract:
碩士國立臺灣師範大學
機電科技研究所
99
The purpose of experiment is aim to a methods of nanofluid produce by arc plasma. Refer to previous research data and correction. Consist with several stages: preparation, modification, system installation, tested; use “Evaporation synthesi- zed condensation system” to implement copper/water nanofluid by selected high energy plasma arc that can vaporize any kind of metal as a heating source, collect vaporized nanoparticle into nanofluid collector. To avoid condensed bigger size of particle due to high temperature or cluster, take paramenter in consideration during the period of experiment; such as working current, collector function, trying to obtain process minimum and average nanoparticle. By mean of two stage experiment, base on different current parameter (50A, 60A, 70A, 80A) collector to gain the proper nanoparticle by target meterial melting situation. Preliminary analyze to determine what type of current maybe optimum parameter. Marcoscopic results show current 60A and 70A are optimum parameter for particle collect on stage one. In the second stage, base on fixed current used three different working current plasma arc torch pulse. Then stimulate with ultrasonic after that, analyze by SEM, EDS, particle size analyzer to define which process can produce perfect nanoparticle. As a result, working current 60A/25Hz average particle is 548nm, 70A/25Hz average particle is 3500nm, process copper/water nanofluid heating resistance test, found that heating resistance reach to -30% under water temperature 50℃, paramenter 70A/25Hz.
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CHEN, HAUAN-CHU, and 陳宣竹. "System software development for automatic Copper Wire Elongation process." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/k9cu6t.
Full textAbstract:
碩士國立勤益科技大學
電子工程系
107
Before the industry conducts automatic wire drawing operations, the wires have been manually thinned and passed through the eye molds. However, increasing labor cost is becoming a big challenge in industry. For this reason, design an automation system software, with the wire through the eye mold mechanism, the software design proposed in this paper includes wire extension system, eye mold crossing system, man-machine interface. PLC is used as a core controller that controls pneumatic cylinder and server motor. Human machine interface is also designed for friendly operation. The simulation performance results confirm that the proposed is capable of carrying out an automatic Copper Wire Elongation process effectively.
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Lin, Ming-Yuan, and 林明源. "Electrochemical Analyses of Leveler Additives in Copper Electrodeposition System." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/13804705372999412483.
Full textAbstract:
碩士國立聯合大學
能源工程學系碩士班
103
High aspect ratio (HAR) though-Si via and though hole filling by copper plating is an important technology for 3D IC package to vertically connect chip-to-chip as interposers. In order to achieve a conformal copper metallization in high aspect ratio vias and holes filling, organic additives such as bis(3-sulfopropyl)disulfide (SPS), polyethylene glycol (PEG), and (Janus Green B, JGB) are commonly used in the Cu plating bath. In this work, a study of concentration effect of additives, the competition adsorption of the leveler additives on the copper electrodeposition, and forced convection behavior are performed by cyclic voltammetry (CV) and the galvanostatic measurements (GM) with rotating disk electrode under a well control of forced convection strength. According to the electrochemical analyses, the acceleration performance of SPS is better than that of MPS. The inhibition behavior of PEG did not increase isometrically with concentration of PEG if the amount of Cl－ ion maintained at the same concentration. The electrochemical behavior of JGB is depended on bias current density and potential. The interaction studies between additives is according to the GM results with different injection sequence. By controlling the selected additives adsorbed on the surface of electrode, the antagonistic adsorption or synergistic behavior was discussed. Furthermore, we introduce a novel lever, Indione Blue (IB), in the plating bath to study the electrochemical behavior. Compare to the traditional lever, JGB, a better inhibit behavior was shown in the CV and GM results. An obvious increase of the cathodic potential was revealed by subsequently inject 1 ppm IB at a current density of 10 mA/cm2 indicating a good inhibit behavior. At the last part, electrolyte containing 0.88 M CuSO4‧5H2O、0.54 M H2SO4, 40 ppm Cl-, 200 ppm PEG, 1 ppm SPS, 1 ppm JGB or 1 ppm IB was used to fill blind holes on Si wafers. The blind holes with diameter of 50 μm and depth of 100 μm were successfully filled with copper electrodeposited at constant current density to achieve a void-free filling of TSV.