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1
Yu, Kyunghee. „Test of copper red glazes in reduction and oxidation“. Virtual Press, 1987. http://liblink.bsu.edu/uhtbin/catkey/495302.
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The problem is to test how the copper red color will turn out depending on the recipes of the glazes and the firing methods. Sixteen different copper red glazes are tested for the reduction and the oxidation firing. Through the repeated firings some glazes are recommended for its consistency and color. It is also learned that the unpredictability is the biggest problem in the reduction firing. Unlike the reduction firing, the result from the oxidation firing is quite consistent, but none of the glazes has the successful local reduction in the oxidation firing.
2
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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3
Howieson, Kathryn E. „A diffuse reflectance infra-red study of the alkali promotion of copper-based catalysts“. Thesis, University of Edinburgh, 1998. http://hdl.handle.net/1842/14113.
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This study concerns the alkali promotion of Cu/ZnO/Al2O3 catalysts which are used for the low temperature water-gas shift reaction. Preliminary high pressure microreactor studies revealed that, on addition of the promoter, an enhanced selectivity to the desired products was achieved rather than for by-product methanol formation. Diffuse Reflectance Infra-red Fourier Transform Spectroscopy (DRIFTS) has been employed during adsorption and subsequent temperature programmed desorption (TPD) and temperature programmed reaction (TPR) experiments in order to determine the mode of action of the promoter. The catalysts were prepared via a layered hydrotalcite-type precursor by co-precipitating the mixed metal nitrates with ammonium bicarbonate, thus generating the catalyst alkali free. Promotion was achieved by impregnation with alkali metal salts. Detailed carbon monoxide adsorption experiments have been used to explore the various parameters in the pre-treatment procedure and their effect on the resultant carbon monoxide stretching band. These studies have also allowed the presence of stepped copper planes to be identified following reduction of the sample, along with partially oxidised copper and a small amount of copper oxide. Catalysts promoted with potassium to different levels (0.02 to 1 weight %) were studied using carbon monoxide as a probe molecule, where the main observation was a sharp attenuation in the CO stretching frequency intensity and a site blocking mechanism of the promoter was invoked in explanation. No shift in the CO stretching frequency was observed. Another, more subtle, effect was identified for the support, bicarbonate formation on alumina was hindered while another surface species with a higher desorption temperature dominated. This was suggested as being a potassium-associated carbonate. Similarly, the effect on the support was seen in analogous carbon dioxide adsorption studies. In addition, the formation of CO following the exposure of the catalysts to CO2 was found to increase on promotion, and, again, a potassium-associated species such as a carboxylate was invoked to explain this.
4
Ni, Wen. „Copper and other mineralization in metamorphosed red beds, West Carbery area, South West Cork, Ireland“. Thesis, University of Birmingham, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.543607.
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More than 100 mineralized localities have been found in the west Carbery area. The stratiform mineralisations are mainly hosted in the top of the predominantly,red coloured Devonian West Cork Sandstone Formation. "Major" sulphide-quartz veins are mainly, hosted in the base of the overlying Devonian Coomhola Formation where green-grey colour is dominant. Apart from the dominant copper sulphides, gold, native bismuth, and a large variety of Cu, Bi, Sb, As and Pb bearing sulphosalts have been found in the vein type mineralisations. Two metamorphic stages metamorphism) have (burial metamorphism and tectonic been recognized. Textures and compositions of phyllosilicates, carbonate compositions and reflectance of carbonaceous materials (graphite) have been used to estimate the metamorphic temperature. The estimated peak metamorphic temperature is 350±25°C and pressure is likely to be -2 kbar on regional geological evidence. Fluid inclusion study and ore mineralogy suggest that "major veins" formed at a temperature of about 300o C.- The trapping pressure obtained from Group 2 subgroup· B inclusions of Ballycurnmisk Veins is about 2 kbar and from other inclusions is < 1kbar. Stable isotope study suggests that vein forming fluids are typical metamorphic fluids. Sulphur from stratiform localities was probably bacterially reduced and sulphur in the "major veins" may be. metamorphically modified from the same ultimate source.
5
KUPFERLE, MARGARET JANE. „FACTORS AFFECTING ELECTROLYTIC TREATMENT OF WASTEWATER CONTAINING DIRECT RED 83, A COPPER-COMPLEXED AZO DYE“. University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1013085676.
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6
Inglis, Patrick Joseph. „A life cycle assessment of utility poles, a comparative analysis of eestern red cedar treated with copper chromated arsenate (CCA), untreated western red cedar, and concrete“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ62021.pdf.
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7
Sandberg, Disa. „Effects of the copper-based antifouling paint "Fabi" on growth of the red alga Ceramium tenuicorne“. Thesis, Södertörns högskola, Institutionen för livsvetenskaper, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-2645.
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The antifouling paint Fabi 3959 is painted on the hulls of vessels to avoid fouling caused by marine organisms attached to surfaces. The paint is registered for use on pleasure boats and other vessels weighing over 200 kg which are mainly running on the Swedish west coast (www.kemi.se). Fabi 3959 contains copper as its active component, which is highly toxic to marine organisms and thus classified as a biocide. Fabi antifouling paint was tested under laboratory conditions on the red macro alga Ceramium tenuicorne, in natural brackish water taken from the Baltic Sea. The Ceramium growth inhibition-test was performed using cloned algae exposed to leakage water with and without sediment. The samples containing only water held concentrations in the range of 0.11% of volume-18% of volume per liter, while the samples using sediment held doses measuring between 0.11% of volume-36% of volume leakage water per liter. The study showed a growth inhibiting effect on the Ceramium in both water and sediment samples down to the lowest concentration used in the test. There was a difference between the water series and the sediment series in the EC50 values of the leakage water. The mean EC50 value was almost 10 times lower within the sediment series compared to the water series (0.114±0.10 and 1.024±0.75, respectively). This indicates that the sediment series are more toxic to Ceramium than the water series. However, if the mean values of EC50 are expressed as copper-concentration, there is no clear difference between the two series (0.59 ± 0.13µg/l for the sediment series and 0.62 ± 0.12 µg/l for the water series). Apparently, the test did not indicate that the sediment was absorbing the copper. Instead it cannot be excluded that another substance involved could have a growth inhibiting impact on Ceramium.Båtbottenfärgen Fabi 3959 målas på fartygsskrov för att undvika påväxt av marina organismer. Färgen är registrerad att användas på fritidsbåtar och andra fartyg med en egenvikt på över 200 kg och med huvudsaklig fart på Västkusten (www.kemi.se). Den aktiva komponenten i Fabi 3959 är koppar, vilket är mycket giftigt för marina organismer och därför klassificeras den som en biocid. Fabi båtbottenfärg testades i laborativ miljö, på den röda makroalgen Ceramium tenuicorne i naturligt brackvatten från Östersjön. Ett tillväxthämningstest utfördes på Ceramium-kloner vilka exponerades för lakvatten i bägare med och utan sediment. Proverna endast innehållande vatten bestod av koncentrationer i intervallen 0,11-18 volym% per liter medan proverna med sedimentvatten hade koncentrationer på 0,11-36 volym% per liter. Studien visade på en signifikant tillväxthämningseffekt på Ceramium i både vatten och sediment, ner till den lägsta använda koncentrationen. Det förelåg en tydlig skillnad mellan vattenserierna och sedimentserierna med avseende på resultaten av EC50-värdena på lakvattnet; EC50-värdena av den toxiska nivån för lakvattnet visade sig ligga tio gånger lägre i sedimentserierna än i vattenserierna (0,114 ± 0,10 i sediment och 1,024 ± 0,75 i vatten). Medelvärdena av EC50 för koppar visar inte någon påtaglig skillnad mellan serierna (0,59 ± 0,13µg/l för sediment 0,62 ± 0,12 µg/l för vatten). Testet indikerade därmed inte att sedimentet absorberade koppar. Istället föreligger en möjlighet att en annan substans orsakade tillväxthämning på Ceramium.
8
Maxwell, Mandy Jill. „The reception and adaptation of oriental ceramics in Britain, with particular reference to Imperial Chinese copper-red wares“. Thesis, University of Glasgow, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428748.
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Norris, Jessica Rose. „Evolution of alteration and mineralization at the Red Chris copper-gold porphyry deposit East zone, northwestern British Columbia, Canada“. Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/42207.
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Located in northwestern British Columbia within the Stikine terrane, the Red Chris Cu-Au porphyry deposit is hosted in the Late Triassic Red Stock (~203.8 Ma). The Red Stock is a quartz monzodiorite to monzonite intrusion hosted in the broadly contemporaneous volcanic rocks of the Stuhini Group. Red Chris has features that are characteristic of calc-alkalic and alkalic porphyry deposits and shares many similarities with the Ridgeway deposit of the Cadia district in New South Wales, Australia. A combined measured and indicated resource of 936 million tonnes at 0.374 % Cu, 0.385 g/t Au, and 1.224 g/t Ag has been outlined from the Main and East zones.
Copper and gold are associated with bornite, chalcopyrite and lesser pyrite, hosted in quartz veins and stockworks as disseminations and fracture-controlled veinlets. High-grade mineralization is directly associated with high quartz vein density. Copper-iron sulphide minerals are laterally zoned, with a bornite > chalcopyrite core, grading outward to a chalcopyrite > pyrite shell and outward and upward to a pyrite > chalcopyrite halo. Five major groups of veins are recognized, of which the oldest two sets contain much of the copper and gold.
Stable isotopic analysis indicates the presence of magmatic and mixed magmatic-meteoric hydrothermal fluids. Evidence from sulphur isotopes demonstrates a high temperature oxidized magmatic fluid was responsible for transporting and depositing much of the copper and gold. A vertical and lateral zonation in sulphur isotopes exists, whereby deep regions exhibit δ34S values between -1.9 to -0.9 % and transition to near-surface regions in the pyrite halo that exhibit δ34S values between +0.9 to +1.9 %. Isotopic analysis of oxygen and deuterium of hydrothermal alteration minerals provide evidence for a magmatic fluid (secondary biotite and muscovite) and a mixed magmatic-meteoric fluid (illite and kaolinite). Low temperature clay alteration (illite-kaolinite; intermediate argillic assemblage) significantly overprinted high temperature alteration (K-silicate, phyllic) in the upper levels of the system and gradually diminished intensity with depth. Carbonate veins and alteration also characterize the shallow levels and isotopic analysis of carbon and oxygen suggest a magmatic source with the possibility of minor mixing with an external meteoric fluid.
10
Simson, William Ronald. „Removing Reds from the Old Red Scar: Maintaining and Industrial Peace in the East Tennessee Copper Basin from the Great War through the Second World War“. Digital Archive @ GSU, 2010. http://digitalarchive.gsu.edu/history_diss/17.
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This study considers industrial society and development in the East Tennessee Copper Basin from the 1890s through World War II; its main focus will be on the primary industrial concern, Tennessee Copper Company (TCC 1899), owned by the Lewisohn Group, New York. The study differs from other Appalachian scholarship in its assessment of New South industries generally overlooked. Wars and increased reliance on organic chemicals tied the basin to defense needs and agricultural advance. Locals understood the basin held expanding economic opportunities superior to those in the surrounding mountains and saw themselves as participants in the nation’s industrial and economic progress, and a vital part of its defense. The study upends earlier scholarship contending local industrial concerns acted proactively to challenges from farmers harmed by industrial pollution; investigation shows firms hesitated to initiate new production processes and manipulated local elections. Partisan developments woven amid all this underscore errors in assuming ancient regional affinity for Republicans. Confederate heritage gave Democrats an historic advantage that fractured before New Deal progressivism and expanding basin Republican power. Markets forced basin firms to merge and embrace technological change affecting working people’s relationships, forcing workers to improve skills or settle for low-skill jobs. Excepting TCC managers and supervisory staff, provincialism ruled; suspicions and competitiveness among workers grew as most miners lived a few scattered villages and most managers and craftsmen settled in the basin’s “Twin-cities” district. Early union efforts collapsed before union mismanagement, rational management and a company union based upon Sam Lewisohn’s ideals. Management managed to wrest control of its industrial relations despite the effects of Depression and the New Deal’s empowerment of workers. Workers’ infighting, reflecting neighborhood demographics and ideological differences, benefitted TCC; it convinced locals TCC could best protect industrial peace. The submissive AFL union installed fit of ownership’s nationally recognized program for industrial relations reliant on federal power. After competition crippled local industry, locals continued their reliance on government: to investigate the medical consequences of extraction work and coordinate environmental restoration. Recent regional anti-government populism makes the basin’s peculiar historic reliance on federal help engaging.
11
Krantz-Frid, Madelene. „Ecotoxicological effects from three antifouling paints on the red macroalga Ceramium tenuicorne.“ Thesis, Södertörns högskola, Institutionen för livsvetenskaper, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-3070.
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Antifouling paints are applied on vessels to prevent growth of fouling organisms such hasbarnacles. Presently, there are a number of different paints available on the Swedish marketwith different strategies and active substances. The paints might work by either continuouslyreleasing biocides or physically by peeling off or provide an easily cleansed surface whereorganisms cannot attach. The physically working paints do not need to register an activesubstance since its purpose is not to affect living organisms by a chemical or biological modeof action. In this study, two commercially available paints, the copper-based Fabi 3959(International Paint Ltd) and physically eroding, biocide-free labelled Mille Light (HempelFärg AB) were compared to Hard Racing superior, containing copper and the forbiddensubstance Tributyltin. Fabi International is only allowed to be used on the Swedish west coastdue to 6% added as active substance while the biocide-free Mille Light is eligible for eastcoast usage. The toxic effect from respective paint was investigated by assembling a growthinhibition test with the red macro alga Ceramium tenuicorne. The results show that all thestudied paints had a negative effect on growth and therefore leaked substances inconcentrations high enough to be harmful to the alga. The toxic response differed with theeffect on growth being in the following order, Hard racing superior>Fabi >Mille Light.Implications regarding the current legalization involving biocide-free labelled antifoulingpaints are discussed.
12
Frese, Thomas Jay. „Acute toxicity of copper sulfate in juvenile red drum (Sciaenops ocellatus) and the establishment of safe methods to control parasitic disease“. FIU Digital Commons, 1994. http://digitalcommons.fiu.edu/etd/3418.
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A series of static 96 hour acute toxicity tests were performed on juvenile red drum of different sizes. The tests were implemented to assess the acute toxicity of copper sulfate to juvenile red drum and establish narrowly defined guidelines for its usage in the treatment of Amyloodinium ocellatum and Cryptocaryon irritans. Median lethal concentrations at which a 50 percent mortality response (LC5 o) were observed ranged from 0.28 mg/1 to 0.88 mg/l in the series of five 96h static acute toxicity tests. A significantly higher sensitivity was observed in early juveniles (2.9 g, 53.3 mm) versus the test runs using older juveniles (11.9, 24.4, 24.7, and 34.4 g). Based on the results of acute toxicity tests and actual experimental treatment regimes performed throughout this study, administration of 0.4 mg/1 CuSO4 for 3h daily over a 14d duration is believed to be a relatively safe, yet effective dose for maturing juvenile red drum.
13
Lecumberri, Sanchez Pilar. „Spatial and temporal evolution of fluids in hydrothermal ore deposits“. Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/50960.
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Magmatic-hydrothermal systems typically have vertical extents of several hundredmeters and their geochemical characteristics (e.g. mineral assemblages) vary considerably
over that vertical extent. As a consequence the expression in outcrop varies depending on
the level of erosion. Therefore understanding the geochemical zonation of magmatic-hydrothermal
ore deposits opens the possibility to detect deep magmatic-hydrothermal
systems, and to assess qualitatively the degree of erosion that has taken place in the area
and at which level the mineralization may occur. This dissertation presents the
characterization of two shallow hydrothermal systems and their potential relations with
deeper magmatic-hydrothermal systems. In addition, this dissertation develops the
equations to directly interpret thermometric data from the fluid inclusion type dominant in
one of those deposits (fluid inclusions that homogenize by halite disappearance).
Red Mountain, AZ is a porphyry copper system with a well-preserved lithocap
providing an ideal candidate to characterize the shallow expression of porphyry copper
systems in the southwestern US. The distribution of fluid inclusions, alteration mineralogy
and grade indicate that the intrusive responsible for the mineralization was only partially
intercepted during the exploration program and that one single magmatic event was likely
responsible for the mineralization detected. Fluid inclusion types and clay minerals are
systematically distributed within the deposit. The fluid responsible for the shallow
hypogene mineralization was a low pH-intermediate temperature-low density fluid while a
high salinity fluid was responsible for deep mineralization.
Wutong is a Pb-Zn-Ag deposit in the Nanling belt (southeast China). The combination
of fluid inclusion and mineral thermometry indicates that the Wutong deposit formed at
relatively low pressures. The age and isotopic composition of the mineralization indicates
that the deposit formed during the Cretaceous from crustal derived fluids. The occurrence
of a shallow magmatic-hydrothermal system of Cretaceous age in this region suggests that
Cretaceous intrusions, despite not outcropping very commonly in this particular region may
occur at deeper levels.
Ph. D.
14
Walter, Sunette. „Characterization of heterotrophic plate count (HPC) bacteria from biofilm and bulk water samples from the Potchefstroom drinking water distribution system / by S. Walter“. Thesis, North-West University, 2009. http://hdl.handle.net/10394/4977.
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The presence of heterotrophic plate count (HPC) bacteria in drinking water distribution systems is usually not considered harmful to the general consumer. However, precautions must be taken regarding the immunocompromised. All water supply authorities in South Africa are lawfully required to provide consumers with high-quality drinking water that complies with South African-and international standards. This study mainly focused on the isolation, identification and characterization of HPC and other bacteria from biofilm-and bulk water samples from two sampling points located within the Potchefstroom drinking water distribution system. Based on five main objectives set out in this study, results indicated that the bulk water at the J.S. van der Merwe building was of ideal quality fit for lifetime consumption. Application of enrichment-and selective media allowed for the isolation of 12 different bacterial morphotypes. These were identified by way of biochemical-and molecular methods as Bacillus cereus, Bacillus subtilis, Brevundimonas spp., Clostridiaceae, Corynebacterium renale, Flavobacteriaceae, Kytococcus sedentarius, Leuconostoc lactic, Lysinibacillus sphaericus, Pseudomonas spp., Staphylococcus aureus and Staphylococcus capitis. The greatest diversity of bacteria was detected early autumn 2008, while the lowest diversity occurred during mid-winter 2007. Bacillus cereus, Kytococcus sedentarius and Staphylococcus capitis displayed potential pathogenic properties on blood agar. Kytococcus sedentarius could be classified as potentially the most pathogenic among the isolates. All isolates displayed multiple-resistant patterns towards tested antibiotics. Corynebacterium renale and Staphylococcus aureus were least resistant bacterial species and Lysinibacillus sphaericus the most resistant. All isolates were susceptible to ciprofloxacin (CIP) and streptomycin (S), but most were resistant to erythromycin (E). Transmission electron microscopy (TEM) allowed for detailed examination of Brevundimonas spp., Pseudomonas spp. and Staphylococcus spp. The capability of Brevundimonas spp. to produce slime and store nutrients within inclusion bodies, suggests the ability of this bacterium to form biofilm and persist in the drinking water for prolonged periods. Despite the inhibitory or toxic effect of copper against bacterial growth, scanning electron microscopy (SEM) revealed the presence of biofilms as well as diatoms on red-copper coupons. Biofilm activity was also observed on reverse-osmosis (RO) filters. Since corrosion was evident on red-copper coupons, it is recommended that prospective studies also look into the significance of microbial induced corrosion (MIC) within the Potchefstroom drinking water distribution system. Other prospects include determining minimum inhibitory concentrations of isolates against antibiotics and the application of culture independent methods such as SSCP and DGGE to investigate biofilm development. The use of diatoms as an index of the drinking water quality is also suggested.Thesis (M.Sc. (Environmental Science))--North-West University, Potchefstroom Campus, 2010.
15
Sutch, Peter John F. „Consumption and loss of formaldehyde in electroless copper plating“. Master's thesis, University of Central Florida, 1993. http://digital.library.ucf.edu/cdm/ref/collection/RTD/id/21775.
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University of Central Florida College of Engineering ThesisThe objectives of this research were to quantify formaldehyde consumption due to plating and parasitic reactions and determine the magnitude and distribution of formaldehyde losses from the electroless copper plating process. Plating and rinse bath samples obtained from three electroless copper plating operations were analyzed for formaldehyde and copper in order to develop a mass balance analysis about the plating bath for periods of active production and no production. Fugitive air and stack releases of formaldehyde were estimated using emission factors developed from air sampling at the three facilities. It was determined that approximately 90% of the formaldehyde added to the plating process was sonsumed by some type of chemical reaction. The remaining 10% of formaldehyde represents losses from the plating operation. For the facilities with a waste plating solution stream, atmospheric losses accounted for approximately 25% of the total losses. The mass of fugitive air formaldehyde measured approximately 2.8 times that escaping through the stack. Dragout accounted for approximately 2.3% of the losses with the remaining going to the waste stream. For the facility without a plating solution waste stream, formaldehyde losses were distributed 59% to atmospheric relases and 41% to the rinse tank. Fugitive and stack releases were approximately the same at 29% of the formaldehyde losses. Formaldehyde consumption due to parasitic reactions for periods of active plating and no plating were determined for two facilities. The rate of parasitic consumption during periods of production was found to be approximately 3 times greater than that for no production. The rate of parasitic consumption was observed to increase with increasing bath temperature.
M.S.;
Civil and Environmental Engineering;
Engineering;
Environmental Engineering;
206 p.
xii, 206 leaves, bound : ill. ; 28 cm.
16
Noirot, Cécile. „Colorations rouge et orange de verres et glaçures sur céramique : étude du redox et de la cristallisation du cuivre“. Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS427.
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Le cuivre est un élément multivalent qui donne aux verres ou aux glaçures une coloration bleue (ions Cu2+), rouge, ou orange (nano ou micro-cristaux de cuivre métallique Cu0 ou de cuprite Cu2O). Ces colorations sont utilisées depuis le début de la manufacture verrière, et se retrouvent dans de nombreux verres archéologiques et historiques, ainsi que dans les glaçures sur céramique. Le contrôle du redox et de la cristallisation lors de l’élaboration des verres rouges ou orange repose cependant sur des recettes en grande partie empiriques. Elles nécessitent la réduction du cuivre à l’aide d’agents réducteurs et/ou d’une atmosphère de fusion réductrice. D’autre part, les procédés de fabrications anciens sont mal connus. L’objectif de cette thèse est d’étudier l’état redox et la cristallisation du cuivre dans les verres silicatés à différentes étapes de l’élaboration de verres rouges et orange. Ainsi, on vérifie que lors de fusions sous air, l’étain permet la réduction du cuivre. On montre que cette réduction continue en même temps que la cristallisation de Cu0 pendant une deuxième étape de recuit. En atmosphère réductrice, on constate que la réduction et la cristallisation peuvent avoir lieu conjointement dans un verre à l’état liquide, mais aussi lors d’un recuit sans fusion réductrice préalable. L’étude est élargie à l’analyse de six tesselles de mosaïque romaines (4eme siècle) rouges et orange. Les parties rouges, colorées par Cu0, et orange, colorées par Cu2O mélangé avec Cu+, coexistent sous forme de rayures dans deux tesselles. L’analyse des compositions établit que les rayures correspondent au même verre de base auquel Cu, Sn et Pb ont été ajoutés, à de plus fortes concentrations pour les parties oranges. Les colorations par Cu2O ne sont pas utilisées en production modernes mais courantes dans les verres archéologiques, et corrélées avec de fortes proportion en cuivre, et souvent en plomb. A partir de nos résultats et d’un bilan de la littérature, un groupe de compositions [haut Cu/ bas Pb] est proposé, et le rôle du plomb dans la formation de Cu2O et la forme de cristaux est discuté. On montre que de fortes concentrations en cuivre et en plomb modifient peu le redox du cuivre. Nos résultats attestent que le choix de la durée et de la température de fusion de verres riches en cuivre et en plomb sont des leviers de contrôle du redox pour obtenir la cristallisation de Cu2OCopper is a multivalent element that colours glasses in blue (Cu2+), red or orange (nano or micro-crystals of metallic copper Cu0 or cuprite Cu2O). These colourations have been used since the dawn of human glass-making and are thus found in numerous archaeological and historical glasses as well as in ceramic glazes. The control of redox and crystallization in the making of these red and orange glasses however rely on somewhat empirical recipes. They require the reduction of copper from added agents or the heating treatment atmosphere. Besides, there are still many unknowns about ancient processes for the production of red and oranges. The purpose of this thesis is to study redox and crystallization of copper in silicate glasses in different steps of the red and orange glasses elaboration. It is thus verified that tin reduces copper when melting in air. We show that this reduction also happen along with crystallization of Cu0 during a second annealing step. In a reducing atmosphere, we observed that reduction and crystallization can happen concurrently in a liquid glass but also during an annealing without previously melting the glass in a reducing atmosphere. The study was broadened to the analysis of six red and orange Roman mosaic tesserae (4th century). The red parts, coloured by Cu0, and the orange one, coloured by Cu2O mixed with Cu+, coexist as stripes in two tesserae. Compositional analyses establish that the stripes correspond to the same base glass to which Cu, Sn and Pb were added, in higher proportions for the orange parts. Colourations by Cu2O are not used in modern production but common in archaeological glasses, and correlated to high copper and often high lead contents. From our results and a literature review, a [high Cu/low Pb] compositional group is put forward, and the role of lead in Cu2O crystallisation is discussed. We show that high copper and lead contents have little impact on copper redox. Our results indicate that the tuning of melting time and temperature of copper and lead-rich glasses is a way to control redox to attain the crystallization of Cu2O
17
Vega-Garcia, Jean-Paul. „Microstructural Investigation of Precipitation Hardened CuNi2S+Zr Alloys for Rotor Applications“. Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2157.
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Industrial generator components experience high stresses and electrical fields during their service life. Material integrity is key in guaranteeing component performance. CuNi2SiZr, used as rotor wedges in generators, serve to maintain rotor slot content in place while experiencing high centrifugal stresses and low cycle fatigue during start and stop at elevated temperature. The quality and integrity of this material in service can be directly related to its microstructure, which is determined by the processing procedures of the wedges. In this study, the microstructure development in this material is evaluated to eliminate grain boundary defects by optimizing processing parameters, determining the best temperature/time combination for precipitation hardening, and determining cold work effect on aging parameters. Two chemistries containing Nickel-to-Silicon ratios of 3.2 and 3.8 were selected for analysis. Cast samples were hot extruded, cold worked, and precipitation hardened. Parameters were varied at each processing step. Five different levels of cold work (4, 5, 7, 10 and 13%) were evaluated using 5 different aging temperatures (450, 460, 470, 490 and 500°C). Each processing parameters' effect on microstructure and subsequently on hardness, conductivity, and tensile strength was recorded to assess material performance and identify grain boundary defects origination. Finding of this study identified observed grain boundary defects, using Transmission Electron Analysis, as voids/micro-tears. These defects on grain boundary are detrimental to low cycle fatigue, creep rupture and tensile strength properties and important aspects of the material performance. Grain boundary defects were observed at all levels of cold work, however, origination of defects was only observed in grain sizes larger than 50µm. The strengthening phases for the CuNi2Si+Zr alloy system were identified as Ni2Si and Cr3Si. The Nickel-to-Silicon ratio had an evident effect on the electrical conductivity of the material. However, aging benefits were not clearly established between the two Nickel-to-Silicon ratios.M.S.M.S.E.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Materials Science & Engr MSMSE
18
Wood, Avery. „Copper Weathervane Pointing Nowhere: Poems“. Honors in the Major Thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/815.
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This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucfBachelors
Arts and Sciences
English; Creative Writing
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Maniprasad, Pavithra. „Novel copper loaded core-shell silica nanoparticles with improved copper bioavailability synthesis, characterization and study of antibacterial properties“. Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4794.
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A novel core-shell silica based antimicrobial nanoparticle was synthesized. The St??ber silica shell has been engineered to accommodate copper. Synthesis of the core-shell Cu-silica nanoparticle (C-S CuSiNP) involves preparation of base-hydrolyzed St??ber silica "seed" particles first, followed by the acid-catalyzed seeded growth of the Cu-silica shell layer around the core. Scanning electron microscopy and transmission electron microscopy showed monodispersed, spherical shaped nanoparticles with smooth surface morphology. Characterization of particle size distribution in solution by the Dynamic Light Scattering (DLS) technique was fairly consistent with the electron microscopy results. Loading of Cu to nanoparticles was confirmed by the SEM-Energy Dispersive X-Ray Spectroscopy (EDS) and Atomic Absorption Spectroscopy (AAS). Antibacterial efficacy of C-S CuSiNP was evaluated against E.coli and B.subtilis using Cu hydroxide ("Insoluble" Cu compound) and copper sulfate as positive control and silica "seed" particles (without Cu loading) as negative control. Minimum Inhibitory Concentration (MIC) of C-S CuSiNP was evaluated by measuring the fluorescent intensity of resorufin to determine the decrease in viable cells with increase in copper concentration in C-S CuSiNP. The MIC value of C-S CuSiNP against both E.coli and B.subtilis was estimated to be 4.9 ppm. Bac-light fluorescence microscopy based assay was used to count relative population of the live and dead bacteria cells. Antibacterial study clearly shows that C-S CuSiNP is more effective than insoluble Cu hydroxide particles and copper sulfate at equivalent metallic Cu concentration, suggesting more soluble Cu in C-S CuSiNP material due to its core-shell design.ID: 031001483; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Title from PDF title page (viewed July 22, 2013).; Thesis (M.S.)--University of Central Florida, 2011.; Includes bibliographical references (p. 43-48).
M.S.
Masters
Molecular Biology and Microbiology
Medicine
Molecular and Microbiology
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Contino, Catherine Marie. „The electromigration behavior of single crystal copper“. Honors in the Major Thesis, University of Central Florida, 2001. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/217.
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This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Engineering
Electrical Engineering
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Read, Elizabeth Stevens. „Investigation of the effects of copper source, copper and zinc levels, and dietary protein source on CU bioavailability in rainbow trout“. Thesis, Montana State University, 2012. http://etd.lib.montana.edu/etd/2012/read/ReadE0512.pdf.
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Limited research has examined the effects that plant-based diets have on copper (Cu) and Zinc (Zn) absorption and utilization in rainbow trout. Few studies have been conducted to determine if interactions exist in the utilization of Cu when increasing levels of supplementary Zn were offered. The objectives of this research were to: first determine what effect protein source (plant vs. animal based), Cu source (complex vs. inorganic) and concentrations of Cu (0, 5, 10, 15, 20 ppm) in the diet had on rate and efficiency of gain and Cu tissue levels in rainbow trout. The second experiment was to determine if interactions occur due to increasing diet content of Zn (0, 30, 300, 1500 ppm) and Cu provided at two levels (0 or 10 ppm) on tissue levels of Cu in rainbow trout. From experiment one, trout fed plant-based diet had higher (P < 0.05) ADG and improved (P < 0.05) FCR in comparison to fishmeal fed trout. Highest (P < 0.05) hepatic Cu concentrations were also observed in trout fed plant-based diets. No differences (P >0.05) were observed in growth or hepatic concentrations due to Cu source. From experiment two, no antagonistic interactions were observed between increasing levels of dietary Zn and Cu. Trout fed the two highest levels of dietary Zn (300 and 1500 ppm) had the greatest (P < 0.05) weight gains. Dietary Zn supplementation increased (P < 0.05) whole body Cu at 12 wks. With increasing dietary Zn supplementation, resulted in increased (P < 0.05) whole body Zn. Cataracts and tail rot were observed at 12 wks in trout fed the Cu and Zn deficient diet. In conclusion, plant-based diets enhanced Cu bioavailability indicated by higher weight gains and hepatic Cu concentrations in experiment one, compared to trout fed fishmeal-based diets. Cu supplementation is required in a plant-based in order to achieve optimal growth in trout. Results of the second study indicate rainbow trout fed plant-based diets require Zn supplementation to obtain sufficient growth. The highest levels of Zn supplementation did not impair Cu uptake in rainbow trout.
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Luo, Ying. „SLURRY CHEMISTRY EFFECTS ON COPPER CHEMICAL MECHANICAL PLANARIZATION“. Master's thesis, University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4470.
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Chemical-mechanical Planarization (CMP) has emerged as one of the fastest-growing processes in the semiconductor manufacturing industry, and it is expected to show equally explosive growth in the future (Braun, 2001). The development of CMP has been fueled by the introduction of copper interconnects in microelectronic devices. Other novel applications of CMP include the fabrications of microelectromechanical systems (MEMS), advanced displays, three dimensional systems, and so on (Evans, 2002). CMP is expected to play a key role in the next-generation micro- and nanofabrication technologies (Singh, et al., 2002). Despite the rapid increase in CMP applications, the fundamental understanding of the CMP process has been lacking, particularly the understanding of the wafer-slurry-pad interactions that occur during the CMP process. Novel applications of CMP are expected to expand to materials that are complex chemically and fragile mechanically. Thus, fundamental understanding and improvement of slurry design for CMP is the key to the development of sophisticated next-generation CMP processes. Slurry performance for CMP can be determined by several output parameters including removal rate, global planarity, surface topography, and surface defectivity. To achieve global planarity, it is essential to form a very thin passivating surface layer (<2 nm) that is subsequently removed by the mechanical component of the slurry (Kaufman et al., 1991) or by combined chemo-mechanical effects (Tamboli, 2000). Chemical additives like hydrogen peroxide (H?O?), potassium ferricyanide, and ferric chloride are added to slurries as oxidizers in order to form a desirable surface layer. Other chemical additives such as inhibitors (e.g. benzotriazole) and complexing agents (e.g. ammonia) are added to the copper slurry in order to modify the oxide layer. That the removal rate of the thin surface layer is greater at the highest regions of the wafer surface than at the lowest regions leads to surface planarity. In this study, various complexing agents and inhibitors are combined to form slurry chemistry for copper CMP processing in H?O? based slurries at pH values ranging from 2 to 10. Two complexing agents (glycine and Ethylenediamine) and one inhibitor (3-amino-1, 2, 4-triazole) were selected as slurry constituents for detailed chemical synergistic effect study because they showed good materials removal and surface planarity performances. To understand the fundamental mechanisms involved in copper CMP process with the afore-mentioned slurry chemical formations, various techniques, such as electrochemical testing techniques (including potentiodynamic polarization and electrochemical impedance spectroscopy), x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM), were applied. As a result, guidelines for optimized slurry chemical formulation were arrived at and the possible mechanisms of surface-chemical-abrasive interactions were determined. From applications point of view, this study serves as a guide for further investigations in pursuing highly effective slurry formulations for copper/low-k interconnect applications.M.S.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Mechanical, Materials and Aerospace Engineering;
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Long, Xiang. „Numerical study on reinforcement mechanism of copper/carbon nanotubes composite“. Master's thesis, University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5409.
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Because of its high stiffness, carbon nanotubes (CNTs) are considered as one of the widely used reinforcement materials in the metal matrix composites. In this thesis, finite element (FE) models were built in Ls-Dyna3D to simulate Copper/CNTs composite deformation and fracture, and to explore CNTs reinforcement mechanisms. Several possible mechanisms were discussed. Deformation and failure of Cu/CNT composites were studied numerically using unit cell FE models, which consist of both metal matrix and CNTs. The simulation results have been verified by existing experiment data reported by Chen's group. The matrix material was modeled as elasto-plastic ductile solids. The CNTs material properties were taken from literature results using molecular dynamics simulation. FE simulations have showed that CNTs deformation exceeds material elastic limit, which means that CNTs plasticity should be taken into account as well. 2D unit cell models were developed using axial symmetric elements with suitable boundary conditions. Several mechanisms are found to affect CNTs reinforcement prediction. The first one is the boundary condition imposed in the models. The CNTs significantly affect the plastic flow of copper during plastic deformation, which is one important reinforcement mechanism. The second reinforcement mechanism is found to be the hardening zone of Cu matrix around CNTs, which is introduced by mismatch of coefficient of thermal expansion (CTE). A round of parametric studies was performed to investigate the effects of several modeling parameters in the FE simulations; these parameters include the volume fraction of CNTs, aspect ratio of CNTs, the size of hardening zone, and the residual plastic strain in the zone. A tool combining Matlab and Ls-Dyna was developed to automatically build 2D unit cell models and automatically post-process simulation results. Picking up suitable parameters, 2D unit cell model results well predict the experimental results from Chen's group. It should be noted that the interface between Cu and CNTs was assumed to be perfect in FE simulations since no CNTs debonding was observed in the experiments. Also, a 3D unit cell model using tetrahedral elements (with element numbers up to one million) was tentatively developed to obtain more accurate results. The purpose was to explore the interface properties of Cu/CNTs, the effect of CNTs orientation distribution, and the other reinforcement mechanism coming from geometry necessary dislocation (GND) since the size of Cu matrix is divided into nano scales by CNTs. 3D unit models are also used to verify the 2D unit cell one, which is a simplified and effective approach. Very interesting results was observed in this part of study. Further works are needed to overcome the difficulties in 3D modeling and the limitation of current CPU speed.ID: 031001326; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Adviser: Yuanli Bai.; Title from PDF title page (viewed April 8, 2013).; Thesis (M.S.M.E.)--University of Central Florida, 2012.; Includes bibliographical references (p. 59-66).
M.S.M.E.
Masters
Mechanical and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering; Thermofluids
24
Hoyt, Sue Allen. „Masters, pupils and multiple images in Greek red-figure vase painting“. Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1150472109.
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Deshpande, Sameer Arun. „SURFACE CHEMISTRY OF APPLICATION SPECIFIC PADS AND COPPER CHEMICAL MECHANICAL PLANARIZATION“. Master's thesis, University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4474.
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Advances in the interconnection technology have played a key role in the continued improvement of the integrated circuit (IC) density, performance and cost. Copper (Cu) metallization, dual damascenes processing and integration of copper with low dielectric constant material are key issues in the IC industries. Chemical mechanical planarization of copper (Cu-CMP) has emerged as an important process for the manufacturing of ICs. Usually, Cu-CMP process consists of several steps such as the removal of surface layer by mechanical action of the pad and the abrasive particles, the dissolution of the abraded particles in the CMP solution, and the protection of the recess areas. The CMP process occurs at the atomic level at the pad/slurry/wafer interface, and hence, slurries and polishing pads play critical role in its successful implementation. The slurry for the Cu-CMP contains chemical components to facilitate the oxidation and removal of excess Cu as well as passivation of the polished surface. During the process, these slurry chemicals also react with the pad. In the present study, investigations were carried out to understand the effect of hydrogen peroxide (H[subscript 2]O[subscript 2]) as an oxidant and benzotriazole (BTA) as an inhibitor on the CMP of Cu. Interaction of these slurry components on copper has been investigated using electrochemical studies, x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS). In the presence of 0.1M glycine, Cu removal rate was found to be high in the solution containing 5% H[subscript 2]O[subscript 2] at pH 2 because of the Cu-glycine complexation reaction. The dissolution rate of the Cu was found to increase due to the formation of highly soluble Cu-glycine complex in the presence of H[subscript 2]O[subscript 2]. Addition of 0.01M BTA in the solution containing 0.1M glycine and 5% H[subscript 2]O[subscript 2] at pH 2 exhibited a reduction in the Cu removal rate due to the formation of Cu-BTA complex on the surface of the Cu further inhibiting the dissolution. XPS and SIMS investigations revealed the formation of such Cu-glycine complex, which help understand the mechanism of the Cu-oxidant-inhibitor interaction during polishing. Along with the slurry, pads used in the Cu-CMP process have direct influence an overall process. To overcome problems associated with the current pads, new application specific pad (ASP) have been developed in collaboration with PsiloQuest Inc. Using plasma enhanced chemical vapor deposition (PECVD) process; surface of such ASP pads were modified. Plasma treatment of a polymer surface results in the formation of various functional groups and radicals. Post plasma treatment such as chemical reduction or oxidation imparts a more uniform distribution of such functional groups on the surface of the polymer resulting in unique surface properties. The mechanical properties of such coated pad have been investigated using nano-indentation technique in collaboration with Dr. Vaidyanathan's research group. The surface morphology and the chemistry of the ASP are studied using scanning electron microcopy (SEM), x-ray photoelectron spectroscopy (XPS), and fourier transform infrared spectroscopy (FTIR) to understand the formation of different chemical species on the surface. It is observed that the mechanical and the chemical properties of the pad top surface are a function of the PECVD coating time. Such PECVD treated pads are found to be hydrophilic and do not require being stored in aqueous medium during the not-in-use period. The metal removal rate using such surface modified polishing pad is found to increase linearly with the PECVD coating time. Overall, this thesis is an attempt to optimize the two most important parameters of the Cu-CMP process viz. slurry and pads for enhanced performance and ultimately reduce the cost of ownership (CoO).M.S.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Mechanical, Materials and Aerospace Engineering
26
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.
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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
27
Gadkari, Parag. „EFFECT OF ANNEALING ON COPPER THIN FILMS:THE CLASSICAL SIZE EFFECT AND AGGLOMERATION“. Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2937.
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With continued shrinking of CMOS technology to reduce the gate delay times, an increase in the resistivity of the metal corresponding to the wire dimension is a concern. This phenomenon of increase in resistivity with decreasing dimension of the thin metallic film or interconnect is known as the "classical size effect". Various theories have been postulated to explain the phenomenon of classical size effect; these theories can be broadly classified as resistivity due to scattering arising from surface and grain boundaries. The total resistivity of metals depends on the electron scattering due to impurities, phonons, surfaces, grain boundaries, and other crystal defects. Managing the size effect in a practical and manufacturing way is of major concern to the microelectronics industry. Since each of the processes (phonon, surface and grain boundary scattering) adds to the resistivity and are interrelated, it further complicates managing the size effect. However, these effects have been separately studied. In this work, the effect of annealing on the classical size effect in Cu thin films deposited on SiO2 substrate is investigated. Polycrystalline Cu thin films having thicknesses in the range of 10nm to 200nm were ultra high vacuum sputter deposited on thermally grown SiO2 surfaces. The films were annealed at temperatures in the range of 150°C to 800°C in argon and argon+3% hydrogen gases. The un-annealed Cu thin films exhibit higher resistivity than the annealed films. The resistivities of un-annealed films were in good agreement with Mayadas and Shatzkes model. When annealed the films undergoes grain growth resulting in lowering the resistivities by about 20%-30% thereby confirming the role of grain size on resistivity of the film. However, there is a limit to annealing, i.e. agglomeration phenomenon. Agglomeration is a thermally activated process resulting in a reduction of the free energy of the film–substrate system and can occur well below the melting point of the material by surface and interfacial diffusion. The reduction of film-substrate interfacial energy, film-surface interfacial energy and stresses within the film are possible driving forces for agglomeration. This work also includes the study of agglomeration phenomenon. The agglomeration behavior of Cu is investigated and compared with that of Ru, Au and Pt thin films with thicknesses in the range of 10 nm to 100 nm UHV deposited on thermally grown SiO2 substrate. The films were annealed at temperatures in the range of 150°C to 800°C in argon and argon+3% hydrogen gases. Scanning electron microscopy was used to investigate the agglomeration behavior, and transmission electron microscopy was used to characterize the microstructure of the as-deposited and annealed films. The agglomeration sequence in all the films is found to follow a two step process of void nucleation and void growth. However, void growth in Au and Pt thin films is different from Cu and Ru thin films. Residual stress and adhesion were observed to play important part in deciding the mode of void growth in Au and Pt thin films. Lastly, it is also observed that the tendency for agglomeration can be reduced by encapsulating the metal film with an oxide overlayer, which in turn improves the resistivity of the thin film due to prolonged grain growth without film breakup.M.S.E.E.
Department of Electrical and Computer Engineering
Engineering and Computer Science
Electrical Engineering
28
Chen, Wei, und 陈伟. „Origin and tectonic environment of the Lala Fe-Cu-(Mo, REE) deposit, Sichuan province, SW China“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/197093.
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The Hekou Group in the Kangdian region, SW Yangtze Block is a metavolcanic-metasedimentary succession hosting the giant Lala Fe-Cu-(Mo, REE) deposit. Mafic volcanic rocks of the Hekou Group and nearby gabbroic intrusions have identical zircon U-Pb ages of ~1700 Ma. The sedimentary and mafic rocks are suggested to have formed in an intra-continental rift, similar to those of the North Australian Craton. Such a similarity suggests that the Yangtze Block was likely linked with the North Australian Craton in the Columbia supercontinent during late Paleoproterozoic.
Overlying the Hekou Group is a thick sedimentary sequence of the Julin Group containing basaltic layers with zircon U-Pb ages of ~1050 Ma. The basalts and other coeval igneous rocks in the region have geochemical affinity of within-plate rocks, representing a ~1.05-1.1 Ga rifting event. Occurrence of the within-plate rocks does not support existence of a Grenvillian orogenic belt in the region, and thus agrues against previous hypothesis that proposed the Yangtze Block to be located in the interior of the Rodinia supercontinent on the basis of the so-called Grenvillian orogenic belt.
The Lala deposit contains 200 Mt of ores with an average grade of 13 wt.% Fe, 0.92 wt.% Cu, 0.018 wt.% Mo, 0.022 wt.% Co, 0.25 wt.% REE2O3 and 0.16 ppm Au, and is one of the largest IOCG deposits in the region. The ores are hosted mostly in meta-vocalnic rocks (albitite) and schists, and are characterized by abundant low-Ti magnetite with subordinate chalcopyrite, pyrite, molybdenite and REE minerals. The paragenetic sequence includes Stage I of Na-alteration, Stage II of Fe mineralization, Stage III of Cu-Mo-REE mineralization, Stage IV of chalcopyrite-pyrite-calcite veins and Stage V of hematite-calcite-quartz veins. Molybdenite of Stage III has a Re-Os isotopic age of 1086 ± 8 Ma, similar to U-Pb ages of the primary allanite as 1067 ± 41 Ma, suggesting that mineralization of the Lala deposit is coeval with the ~1.05-1.1 Ga within-plate magmatism in the region. The secondary allanite has U-Pb ages of 880-850 Ma, comparable to Ar-Ar and Pb-Pb ages of undeformed Stage IV and V veins, representing a younger hydrothermal event.
C-O-S isotopes suggest that the Fe and Cu mineralization stages (II and III) at Lala have formed from high temperature magmatic-hydrothermal fluids (385-430ºC). However, compositions of fluid inclusions and minerals demonstrate that the Fe and Cu mineralizing fluids have different compositions. Strontium isotopic compositions of apatite and calcite suggest that the Fe mineralizing fluid has formed from magmatic fluids interacted with late Paleoproterozoic host rocks, whereas the Cu mineralizing fluid with much higher 87Sr/86Sr ratios has possibly involved magmatic fluids that have interacted with older basement beneath. Close association of monazite-bearing apatite, Cu-sulfides and REE-minerals at Lala suggests that REE mobilization and mineralization is genetically related to the Cu mineralizing fluid. This study suggests that the Cu mineralizing fluid contains Cl-, K, CO2, F-, PO43- and CO32- with low Na activity, and is thus responsible for mobilization, transportation and deposition of LREEs in the Lala deposit.published_or_final_version
Earth Sciences
Doctoral
Doctor of Philosophy
29
Earls, Alison. „Genuine cherry red : a fiction novel“. Thesis, Queensland University of Technology, 2003.
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"Genuine Cherry Red" is a fiction novel.
It is the story of three people who live in a house beside a hill in the flattest place on earth - an almost fable-like setting. In different ways, each is locked inside the order and control they have constructed through the years. Surrounded by nature and its reliable cycle, they are resisting change and denying the unpredictable randomness of life. Marta is a young woman who is both intelligent and naïve, caught inside a private maze of thinking and rethinking. She lives with her mother's cousin Ena who gave up nursing to take Marta in when her mother succumbed to depression, and Ena' s husband Len, a successful and prolific writer of cowboy fiction. Since a cancer diagnosis, Len - who had been living with multiple
sclerosis - has been virtually catatonic ... until Grey Bob suddenly arrives. The central character of Len's fictional stories permeates their lives and things begin to change.
The natural environment, the people of the nearby town, the order of the house all transform and Marta, Ena and Len struggle to cope. But they have no choice. When the inevitable shifts occur, spontaneous events have impact and disease progresses, each member of the family eventually finds a way to deal with the fact that reality can be
haphazard and out of their control. So, through the presence of a fictional character, three people are forced to confront the erratic nature of human life.
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Vaidya, Rajendra D. „USING ELECTROCHEMICAL MONITORING TO PREDICT METAL RELEASE IN DRINKING WATER DISTRIBUTION SYSTEMS“. Doctoral diss., University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3982.
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ABSTRACT Corrosion of distribution system piping and home plumbing materials is a major concern in the water community. Iron release adverse affects aesthetic water quality and the release of copper and lead is regulated by the Lead and Copper rule (LCR) and can adversely affect consumer health. Corrosion control is typically done by pH regulation and/or addition of corrosion inhibitors. Monitoring of corrosion control is typically done after the fact by monitoring metal release, functional group concentration of the selected chemical species or water quality. Hence, the associated laboratory analyses create a significant delay prior to the assessment of corrosion in drinking water systems. As corrosion in drinking water systems is fundamentally an electrochemical process, measurement of the electrical phenomena associated with corrosion can be use for real-time corrosion monitoring. This dissertation focuses on using parameters associated with electrochemical corrosion monitoring (EN) measurements in a field facility to predict and control the release of Iron, Copper and Lead in finished waters produced from ground, surface and saline sources with and without usage of corrosion inhibitors. EN data has not been used previously to correlate water quality and metal release; hence the use of EN data for corrosion control in drinking water systems has not been developed or demonstrated. Data was collected over a one year period from a large field facility using finished waters that are distributed to each of the fourteen pilot distribution systems (PDSs), corrosion loops and Nadles each. The PDSs have been built from aged pipes taken from existing distribution systems and contain links of PVC, lined cast Iron, unlined cast Iron and galvanized Steel pipe. The effluent for each PDS was split in two parts. One was delivered to the corrosion loops which are made from coiled copper pipe with lead-tin coupon inserted inside each loop and the other was delivered to the Nadles which housed the EN probes with electrodes for Fe or Cu or Pb-Sn. Finished water quality was monitored in and out of each PDS and total and dissolved Copper and Lead were monitored out of each corrosion loop. Photographs, scanning electron microscope (SEM) micrographs and energy disruptive x-ray spectroscopy (EDAX) conducted on all EN electrodes. EN electrodes showed dark brown to blackish voluminous scales for Fe, and EDAX revealed occurrence of two scales in distinct areas for all Fe electrodes; one comprised of porous, spongy looking structures and scales with more Fe content where the other had denser and more compact scales richer in Ca and P or Si. Cu electrodes had an orange to dark brown thin scale with blue green spots. Small pits were consistently observed mostly in the centre of such blue green spots which were identified as copper carbonates. The Pb electrodes visually showed a thin shiny transparent film with a surface very similar to the unexposed electrodes. Numerous pits were visually for pH controls and not seen for inhibitors; but SEM revealed that all electrodes had pits but the inhibitors reduced number and size of pits compared with pH controls. Thin hexagonal hydrocerussite plates were observed to occur in distinct growth areas and the presence of P or Si inhibitor seemed to increase the occurrence of hydrocerussite. Both Fe & Pb release were mostly in the particulate form while Cu release was mostly in the dissolved form. Total and dissolved Fe, Cu and Pb release models using EN parameters were developed by nonlinear regression. Fe release increased with localized corrosion (PF) and the EN model predicts that Fe release can be effectively controlled to the same degree by pH elevation or inhibitors. Cu release increased with general corrosion (LPRCR) and was also influenced by localized corrosion (ECNCR). However general corrosion was more significant for copper release which was mostly in the dissolved form. Pb release was depended on both general corrosion (LPRCR & HMCR) and localized corrosion (PF). The EN models predict that both Cu and Pb release is highest for pH control and all inhibitors reduced Cu and Pb release, which is consistent with the data. Inhibitors ranked by increasing effectiveness for reducing both Cu and Pb release are pH elevation, Si, ZOP, OP and BOP. EN monitoring is faster and less labor intensive than water quality monitoring and represents a significant advance for controlling metal release in drinking water distribution systems. The EN models were found to be comparable to water quality models developed from this study for metal release, and since EN is a real-time technique it offers a tremendous advantage over traditional water quality sampling techniques. Remote access of EN monitoring equipment is possible and the system requires little to no maintenance with the exception of a power supply or battery. The rapid turn around of corrosion rates from EN can be used to estimate metal release in drinking water proactively and mitigating measures can be implemented before the full adverse impacts are realized.Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engineering PhD
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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
32
Withanage, Wenura Kanchana. „MAGNESIUM DIBORIDE (MGB2) THIN FILMS ON COPPER AND SILICON FOR RADIOFREQUENCY CAVITY AND ELECTRONIC APPLICATIONS“. Diss., Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/539283.
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PhysicsPh.D.
Magnesium diboride is a known material since the 1950s. However, superconductivity in MgB2 was discovered in 2001. Soon after the discovery of superconductivity in MgB2, there was a rush to understand its complex nature of superconductivity and other properties. However, current research in MgB2 is mainly focused on applications. MgB2 possesses excellent superconducting properties such as a high transition temperature (Tc) of 39 K, a high critical current density (Jc) of ~107 A·cm-2, a high thermodynamic critical field (Hc), absence of weak links at grain boundaries, etc. Because of these properties, it is considered one of the candidate materials for applications such as superconducting wires, superconducting radiofrequency (SRF) cavities, superconducting electronic devices, etc. SRF cavities play an important role in modern particle accelerators. The main objective of an SRF cavity is to accelerate charged particle beams. SRF cavities are characterized by two figures of merit: the quality factor (Q) and the accelerating gradient (Eacc). Q characterizes the energy efficiency of an RF cavity and Eacc is the average accelerating field of an RF cavity. The state-of-the-art SRF technology is based on niobium. It is a well-matured technology and it is reaching the theoretical limits on both Q and Eacc. Additionally, Nb cavities operate at 2 K, which requires large-scale liquid helium refrigeration and distribution systems. This adds substantial capital and operational costs for large particle accelerators such as HL-LHC and proposed ILC. Because of these reasons, new SRF materials with higher Q, higher Eacc, and higher operational temperatures are desired. Currently, few superconducting materials such as Nb3Sn and MgB2 are in the research and development process. Nb3Sn has a Tc of 18 K, which is significantly lower than the Tc of MgB2. MgB2-coated cavities are theoretically predicted to have higher Q and Eacc compared to Nb cavities. In addition, owing to its high Tc, MgB2-coated cavities are expected to operate above 4.2 K (20-25 K). Operation at around 20–25 K will allow the use of hydrogen- or neon-based cryocooler technology, eliminating the use of helium. This will substantially reduce the capital and operational cost of a MgB2-based accelerator. However, this will not be possible with Nb3Sn-based SRF cavities due to the low Tc of Nb3Sn. The main goal of the research presented in this thesis is to develop MgB2-coated copper superconducting radiofrequency cavities utilizing hybrid physical-chemical vapor deposition (HPCVD) technique. MgB2-coated Cu SRF cavities will have an added advantage due to the high thermal conductivity of the Cu. The excellent thermal conductivity of Cu enhances the heat transfer between the superconducting MgB2 layer and the cavity body, thus providing better resistance to thermal breakdown. RF characterization of MgB2–coated Cu is a crucial requirement because it is the first step toward the MgB2 –coated Cu SRF cavities. For these characterizations, small-sized samples (e.g., 2-inch diameter) are usually required. Among several MgB2 growth techniques, the HPCVD process produces the best quality MgB2 thin films. However, the growth of MgB2 films on Cu using the HPCVD technique is challenging as Mg, and Cu readily react to form several Mg-Cu alloys. Therefore, a new MgB2 growth process on Cu was developed by modifying the existing HPCVD process and in the new process, the deposition takes place at ~470 °C. With this new process, high-quality MgB2 thin films were successfully deposited on 2-inch diameter Cu discs, and these samples were characterized in terms of structural and superconducting properties. Surface morphology showed well-connected crystallites with no pinholes on the coating, and the cross-sectional studies showed conformal growth of MgB2 on Cu. The Tc of these samples were ~37 K and the ~107 A·cm-2 zero field Jc was observed. Most importantly, RF characterizations at 11.4 GHz showed Q close to 2 x 107 at 4 K, which was comparable to the Q of Nb. After successful RF testing of MgB2-coated Cu discs, this process was scaled up to coat 3 GHz Cu RF cavities. As the first step, a MgB2 thin film was synthesized on the inner wall of Cu tubes with dimensions (~1.5-inch inner diameter and 8-inch length), similar to a beam tube of a 3 GHz RF cavity. The MgB2 film on the Cu tubes showed conformal coating with Tc ~37 K. Next, the coating of the 3 GHz Cu test cavity was carried out. Cu test cavities were assembled using two half-cells pressed at Thomas Jefferson National Accelerator Facility (JLab) and two beam tubes machined at Temple University. The MgB2 film was successfully synthesized on the inner wall of 3 GHz test cavities and the MgB2 coating on the two half-cells showed uniform growth with Tc distributed around 35 K. However, slight damages to the cavity wall were observed and these damages were mainly due to the deformation of the Cu surface, caused by the formation of Mg-Cu alloy liquid. Current research is focused on developing damage-free MgB2-coated Cu RF cavities. In addition to MgB2 growth on Cu for SRF cavity applications, development of high-quality MgB2 thin film on Si substrates was carried out. This will be used in electronic device applications such as fabrication of hot-electron bolometers (HEB). An issue similar to the Mg-Cu reaction was observed with Si; Si and Mg react at elevated temperatures, forming Mg2Si, and this was observed at around 550°C. This reaction prevents the use of the HPCVD technique directly on Si. Previous attempts at synthesizing MgB2 films on Al2O3-buffered Si substrates at low temperatures (500–600°C) were reported. However, these films have shown extremely rough surfaces with poor superconducting properties. In this work, a ~220 nm-thick boron buffer layer was used to prevent the Mg-Si reaction, and it was observed that the boron was effective even above 700°C. High-quality MgB2 thin films were synthesized on boron-buffered Si substrates using the standard HPCVD technique. However, the resultant films showed enhanced roughness due to the polycrystalline growth. Ar ion milling at an ultra-low angle (1°) was used to smooth the MgB2 films, and the resultant films showed roughness comparable to epitaxial films grown on SiC substrates with a slight degrade in superconducting properties. Finally, Al ion implantation in the MgB2 thin film was studied and this project was carried out to synthesize MgB2 films with modified superconducting properties. In this study, 80 nm-thick MgB2 films were irradiated with a 75 keV Al ion beam. A 30 nm Au buffer layer was used on top of the MgB2 films in order to position the projected range of Al ions near the center of the MgB2 films. Al ion doses were kept between 2×1011–1×1016 atoms·cm-2. Superconducting properties and the structural properties of these Al ion irradiated films showed systematic change with the Al dose. Superconducting transition temperature decreased with increasing Al dose. Also, for the Al ion dose at or above 2 × 1014 atoms·cm-2, the irradiated samples did not show any superconducting transition. Al ion irradiated films showed an increase in the c-axis lattice parameter of MgB2 with increasing ion dose. These observed changes in the superconducting properties and structural properties of Al ion irradiated films can be attributed to the ion damage.
Temple University--Theses
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Engström, Erik. „Direct poly(A) RNA nanopore sequencing on the freshwater duck mussel Anodonta anatina following exposure to copper : A pilot study“. Thesis, Högskolan i Skövde, Institutionen för biovetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-17508.
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Aquatic ecotoxicology is the study of toxic chemicals and its effects on aquatic biological systems with the aim of minimising threats to human health and ensure self-sustained ecosystems. Freshwater bivalves are excellent sentinels for use in ecotoxilogical research due to their filter feeding properties, stationary lifestyle and inability to regulate body temperature. This project aimed to assess the feasibility and use of nanopore sequencing, a real-time single-molecule sequencing technology in comparative expression analysis by sequencing transcriptomic RNA from the freshwater mussel Anodonta anatina following exposure to copper. RNAs were extracted from 80 mg hepatopancreas tissue, followed by poly(A) RNA selection. Furthermore, the poly(A) RNA was used to construct a nanopore sequencing library. Sequencing a total amount of 560 ng poly(A) RNA over the course of two separate runs generated 239,448 reads, in which 75% of the reads were obtained during the first run (control) and 25% of the reads were obtained during the second run (case). The median read lengths ranged between 534-650 nucleotides, with a base call accuracy <90%. Due to the big differences in sequence data output between the two sequencing runs, the data was ineligible for comparative analysis. The findings conclude that nanopore sequencing is capable of generating longer read lengths when compared to other sequencing platforms. However, the technology is error-prone in terms of accurate base call identifications and relies on other platforms for error corrections. Future advances include de novo transcriptome assembly for efficient use of Anodonta anatina as a bioindicator in aquatic ecotoxicology.
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Jones, Jamie. „Chemophysical Characteristics and Application of Biosorption Activated Media (BAM) for Copper and Nutrient Removal in Stormwater Management“. Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5954.
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For high groundwater table areas, stormwater wet detention ponds are utilized as the preferred stormwater management throughout the state of Florida. Previous research has found that accumulations of nutrients, algae, heavy metals, pesticides, chlorophyll a, fecal coliform bacteria and low concentrations of dissolved oxygen (DO) are common characteristics of stormwater wet detention ponds. Although these pollutant levels are not regulated within the ponds, states are required to compute the pollutant load reductions through total maximum daily load (TMDL) programs to meet the water quality requirements addressed by the Clean Water Act (CWA). In this study, field sampling data of stormwater ponds throughout Florida are presented to identify concentration levels of the main contaminants of concern in the discharge of wet detention ponds. Sampling was done to identify possible sources, in addition to possible removal mechanisms via the use of specific sorption media. Nutrients were found as a main problematic pollutant, of which orthophosphate, total phosphorus, ammonia, nitrate, and total nitrogen were targeted whereas heavy metals exhibited minor concerns. Accumulation of high nutrient concentrations may be mitigated by the adoption of best management practices (BMPs) utilizing biosorption activated media (BAM) to remove phosphorus and nitrogen species through physical, chemical, and biological processes. This study aims to increase overall scientific understanding of phosphorus removal dynamics in sorption media systems via Langmuir and Freundlich isotherms and column studies. The removal of phosphorus (P) was proven effective primarily through chemophysical processes. The maximum orthophosphate adsorption capacities were determined under varying conditions of the media within the columns, which were found up to 0.000534 mg-P adsorbed per gram BAM with influent concentrations of 1 mg?L-1 orthophosphate in distilled water and 1 hour hydraulic residence time (HRT). When using spiked pond water under the same conditions, the adsorption capacity was increased about 30 times to 0.01507 mg-P?g-1 BAM presumably due to the properties and concentrations of ions affecting the diffusion rate regulating the surface orthophosphate reactions. These equilibrium media uptake values (q) were used to calculate the life expectancies of the media under varying HRT and influent concentrations of treatment. Chemophysical and biological removal capabilities of the media for total nitrogen, ammonia, and nitrate were effective in columns using 1100 g of BAM. In flow-through column conditions, ammonia had a consistent ~95% removal while effluent nitrate concentrations were highly variable due to the simultaneous nitrification-denitrification processes once an aerobic-anaerobic environment was established. Batch column experiments simulating no-flow conditions within a media bed reactor resulted in orthophosphate removals comparable with the continuous flow conditions, increased total phosphorus effluents indicative of chemical precipitation of orthophosphate, decreased ammonia removal, and increased nitrate removal. Due to a biofilm's sensitivity to even low copper concentrations and accumulation in ponds, a copper sorption media mix of “green” materials was generated. Freundlich and Langmuir isotherm tests concluded a successful mix resulting in copper removal efficiencies up to 96%.M.S.
Masters
Civil, Environmental, and Construction Engineering
Engineering and Computer Science
Environmental Engineering; Environmental Engineering Sciences
35
McIntosh, Melissa Clark Timothy B. „Copper-catalyzed diboration of ketones : facile synthesis of tertiary a-Hydroxyboronate esters /“. Online version, 2010. http://content.wwu.edu/cdm4/item_viewer.php?CISOROOT=/theses&CISOPTR=336&CISOBOX=1&REC=11.
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36
Lattanzi, Gregory Denis. „THE VALUE OF RECIPROCITY: COPPER, EXCHANGE AND SOCIAL INTERACTION IN THE MIDDLE ATLANTIC REGION OF THE EASTERN WOODLANDS OF NORTH AMERICA“. Diss., Temple University Libraries, 2013. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/237820.
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AnthropologyPh.D.
Native Americans in the Eastern Woodlands participated in extensive trade networks with their surrounding neighbors, beginning over 4,500 years ago. Lithics, perishable goods, exotics, and knowledge have crisscrossed the landscape throughout prehistory. By determining a general region from which copper artifacts originated and linking it with the location of their use and eventual discard, this research reveals "trade" patterns and thus advances our understanding of culture change in the Eastern Woodlands. This project focuses on evaluating the nature and extent of this interaction using copper artifacts from Early to Middle Woodland period sites within the Middle Atlantic region. These sites include Abbott Farm and Rosenkrans Ferry in New Jersey and Nassawango in Maryland. This study uses laser ablation multi-collector inductively coupled plasma-mass spectrometry to examine trace-element concentrations of copper in artifacts and thus tests existing regional models of prehistoric exchange. By examining the elemental composition of copper this study was able to determine whether the artifacts from these sites were made on raw material from single or multiple geological sources, and where those sources might be located. The elemental study showed that geologic sources of copper represented by the artifacts found on a site could have come from Pennsylvania, New Jersey, North Carolina and Canada. These geological sources are all located within the eastern United States. This helped to clarify how native peoples in the Middle Atlantic Region acquired copper and whether current reconstructions of ancient patterns of trade could account for the regional distribution of copper artifacts. A series of expectations based on interpretations of the chemical data were constructed to evaluate existing exchange models. Certain aspects of the exchange models did hold up in light of this study. A broad-based (down the line) exchange network was identified for the Early Woodland site examined in this study. Similarly, broad-based exchange networks were seen at Middle Woodland sites; with the addition of a more complex focused exchange network with copper coming from within the region. This means that prehistoric groups in this region, while they appear to exhibit signs of increased socio-cultural complexity, provide stronger evidence of a reciprocally shared ideology based on probable kin relations. Similarly, these results agree with previous copper sourcing studies carried out in the mid-continent. Identifying the provenance of artifacts used in exchange networks is important for understanding interactions among prehistoric groups and the impact of these networks on social organization. Furthermore, by combining geological, archaeological, and anthropological data this research elucidates processes of material resource acquisition and determines if they change through time. Research into the identification of raw material sources, the archaeological context of exotic artifacts, the movement of those artifacts between groups, and the significance or value attached to those artifacts through the act of exchange all contribute to an understanding of prehistoric behavioral and social processes.
Temple University--Theses
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Stone, Erica. „EFFECTS OF ORTHOPHOSPHATE CORROSION INHIBITOR IN BLENDED WATER QUALITY ENVIRONMENTS“. Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2961.
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This study evaluated the effects of orthophosphate (OP) inhibitor addition on iron, copper, and lead corrosion on coupons exposed to different blends of groundwater, surface water, and desalinated seawater. The effectiveness of OP inhibitor addition on iron, copper, and lead release was analyzed by statistical comparison between OP treated and untreated pilot distribution systems (PDS). Four different doses of OP inhibitor, ranging from zero (control) to 2 mg/L as P, were investigated and non-linear empirical models were developed to predict iron, copper, and lead release from the water quality and OP doses. Surface characterization evaluations were conducted using X-ray Photoelectron Spectroscopy (XPS) analyses for each iron, galvanized steel, copper, and lead/tin coupon tested. Also, a theoretical thermodynamic model was developed and used to validate the controlling solid phases determined by XPS. A comparison of the effects of phosphate-based corrosion inhibitor addition on iron, copper, and lead release from the PDSs exposed to the different blends was also conducted. Three phosphate-based corrosion inhibitors were employed; blended orthophosphate (BOP), orthophosphate (OP), and zinc orthophosphate (ZOP). Non-linear empirical models were developed to predict iron, copper, and lead release from each PDS treated with different doses of inhibitor ranging from zero (control) to 2 mg/L as P. The predictive models were developed using water quality parameters as well as the inhibitor dose. Using these empirical models, simulation of the water quality of different blends with varying alkalinity and pH were used to compare the inhibitors performance for remaining in compliance for iron, copper and lead release. OP inhibitor addition was found to offer limited improvement of iron release for the OP dosages evaluated for the water blends evaluated compared to pH adjustment alone. Empirical models showed increased total phosphorus, pH, and alkalinity reduced iron release while increased silica, chloride, sulfate, and temperature contributed to iron release. Thermodynamic modeling suggested that FePO4 is the controlling solid that forms on iron and galvanized steel surfaces, regardless of blend, when OP inhibitor is added for corrosion control. While FePO4 does not offer much control of the iron release from the cast iron surfaces, it does offer protection of the galvanized steel surfaces reducing zinc release. OP inhibitor addition was found to reduce copper release for the OP dosages evaluated for the water blends evaluated compared to pH adjustment alone. Empirical models showed increases in total phosphorus, silica, and pH reduced copper release while increased alkalinity and chloride contributed to copper release. Thermodynamic modeling suggested that Cu3(PO4)2•2H2O is the controlling solid that forms on copper surfaces, regardless of blend, when OP inhibitor is added for corrosion control. OP inhibitor addition was found to reduce lead release for the OP dosages evaluated for the water blends evaluated compared to pH adjustment alone. Empirical models showed increased total phosphorus and pH reduced lead release while increased alkalinity, chloride, and temperature contributed to lead release. Thermodynamic modeling suggested that hydroxypyromorphite is the controlling solid that forms on lead surfaces, regardless of blend, when OP inhibitor is added for corrosion control. The comparison of phosphate-based inhibitors found increasing pH to reduce iron, copper, and lead metal release, while increasing alkalinity was shown to reduce iron release but increase copper and lead release. The ZOP inhibitor was not predicted by the empirical models to perform as well as BOP and OP at the low dose of 0.5 mg/L as P for iron control, and the OP inhibitor was not predicted to perform as well as BOP and ZOP at the low dose of 0.5 mg/L as P for lead control. The three inhibitors evaluated performed similarly for copper control. Therefore, BOP inhibitor showed the lowest metal release at the low dose of 0.5 mg/L as P for control of iron, copper, and lead corrosion.Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engineering PhD
38
Lintereur, Phillip. „EFFECTS OF SOURCE WATER BLENDING FOLLOWING TREATMENT WITH SODIUM SILICATE AS A CORROSION INHIBITOR ON METAL RELEASE WITHIN A WAT“. Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2967.
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A study was conducted to investigate and quantify the effects of corrosion inhibitors on metal release within a pilot distribution system while varying the source water. The pilot distribution system consisted of pre-existing facilities from Taylor et al (2005). Iron, copper, and lead release data were collected during four separate phases of operation. Each phase was characterized by the particular blend ratios used during the study. A blended source water represented a water that had been derived from a consistent proportion of three different source waters. These source waters included (1) surface water treated through enhanced coagulation/sedimentation/filtration, (2) conventionally treated groundwater, and (3) finished surface water treated using reverse osmosis membranes. The corrosion inhibitors used during the study were blended orthophosphate (BOP), orthophosphate (OP), zinc orthophosphate (ZOP), and sodium silicate (Si). This document was intended to cite the findings from the study associated with corrosion treatment using various doses of sodium silicate. The doses were maintained to 3, 6, and 12 mg/L as SiO2 above the blend-dependent background silica concentration. Sources of iron release within the pilot distribution system consisted of, in the following order of entry, (1) lined cast iron, (2) un-lined cast iron, and (3) galvanized steel. Iron release data from these materials was not collected for each individual iron source. Instead, iron release data represented the measurement of iron upon exposure to the pilot distribution system in general. There was little evidence to suggest that iron release was affected by sodium silicate. Statistical modeling of iron release suggested that iron release could be described by the water quality parameters of alkalinity, chlorides, and pH. The R2 statistic implied that the model could account for only 36% of the total variation within the iron release data set (i.e. R2 = 0.36). The model implies that increases in alkalinity and pH would be expected to decrease iron release on average, while an increase in chlorides would increase iron release. The surface composition of cast iron and galvanized steel coupons were analyzed using X-ray photoelectron spectroscopy (XPS). The surface analysis located binding energies consistent with Fe2O3, Fe3O4, and FeOOH for both cast iron and galvanized steel. Elemental scans detected the presence of silicon as amorphous silica; however, there was no significant difference between scans of coupons treated with sodium silicate and coupons simply exposed to the blended source water. The predominant form of zinc found on the galvanized steel coupons was ZnO. Thermodynamic modeling of the galvanized steel system suggested that zinc release was more appropriately described by Zn5(CO3)2(OH)6. The analysis of the copper release data set suggested that treatment with sodium silicate decreased copper release during the study. On average the low, medium, and high doses decreased copper release, when compared to the original blend source water prior to sodium silicate addition, by approximately 20%, 30%, and 50%, respectively. Statistical modeling found that alkalinity, chlorides, pH, and sodium silicate dose were significant variables (R2 = 0.68). The coefficients of the model implied that increases in pH and sodium silicate dose decreased copper release, while increases in alkalinity and chlorides increased copper release. XPS for copper coupons suggested that the scale composition consisted of Cu2O, CuO, and Cu(OH)2 for both the coupons treated with sodium silicate and those exposed to the blended source water. Analysis of the silicon elemental scan detected amorphous silica on 3/5 copper coupons exposed to sodium silicate. Silicon was not detected on any of the 8 control coupons. This suggested that sodium silicate inhibitor varied the surface composition of the copper scale. The XPS results seemed to be validated by the visual differences of the copper coupons exposed to sodium silicate. Copper coupons treated with sodium silicate developed a blue-green scale, while control coupons were reddish-brown. Thermodynamic modeling was unsuccessful in identifying a controlling solid that consisted of a silicate-based cupric solid. Lead release was generally decreased when treated with sodium silicate. Many of the observations were recorded below the detection limit (1 ppb as Pb) of the instrument used to measure the lead concentration of the samples during the study. The frequency of observations below the detection limit tended to increase as the dose of sodium silicate increased. An accurate quantification of the effect of sodium silicate was complicated by the observations recorded below detection limit. If the lead concentration of a sample was below detection limit, then the observation was recorded as 1 ppb. Statistical modeling suggested that temperature, alkalinity, chlorides, pH, and sodium silicate dose were important variables associated with lead release (R2 = 0.60). The exponents of the non-linear model implied that an increase in temperature, alkalinity, and chlorides increased lead release, while an increase in pH and sodium silicate dose were associated with a decrease in lead release. XPS surface characterization of lead coupons indicated the presence of PbO, PbO2, PbCO3, and Pb3(OH)2(CO3)2. XPS also found evidence of silicate scale formation. Thermodynamic modeling did not support the possibility of a silicate-based lead controlling solid. A solubility model assuming Pb3(OH)2(CO3)2 as the controlling solid was used to evaluate lead release data from samples in which lead coupons were incubated for long stagnation times. This thermodynamic model seemed to similarly describe the lead release of samples treated with sodium silicate and samples exposed to the blended source water. The pH of each sample was similar, thus sodium silicate, rather than the corresponding increase in pH, would appear to be responsible if a difference had been observed. During the overall study, the effects of BOP, OP, ZOP, and Si corrosion inhibitors were described by empirical models. Statistically, the model represented the expected value, or mean average, function. If these models are to be used to predict a dose for copper release, then the relationship between the expected value function and the 90th percentile must be approximated. The USEPA Lead and Copper Rule (LCR) regulates total copper release at an action level of 1.3 mg/L. This action level represents a 90th percentile rather than a mean average. Evaluation of the complete copper release data set suggested that the standard deviation was proportional to the mean average of a particular treatment. This relationship was estimated using a linear model. It was found that most of the copper data sub-sets (represented by a given phase, inhibitor, and dose) could be described by a normal distribution. The information obtained from the standard deviation analysis and the normality assumption validated the use of a z-score to relate the empirical models to the estimated 90th percentile observations. Since an analysis of the normality and variance (essentially contains the same information as the standard deviation) are required to assess the assumptions associated with an ANOVA, an ANOVA was performed to directly compare the effects of the inhibitors and corresponding doses. The findings suggested that phosphate-based inhibitors were consistently more effective than sodium silicate when comparing the same treatment levels (i.e. doses). Among the phosphate-based inhibitors, the effectiveness of each respective treatment level was inconsistent (i.e. there was no clear indication that any one phosphate-based inhibitor was more effective than the other). As the doses increased for each inhibitor, the results generally suggested that there was a corresponding tendency for copper release to decrease.Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Electrical Engineering PhD
39
Pethe, Shirish A. „Optimization of process parameters for reduced thickness CIGSeS thin film solar cells“. Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4623.
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With the advent of the 21st century, one of the serious problems facing mankind is harmful effects of global warming. Add to that the ever increasing cost of fuel and the importance of development of clean energy resources as alternative to fossil fuel has becomes one of the prime and pressing challenges for modern science and technology in the 21st century. Recent studies have shown that energy related sources account for 50% of the total emission of carbon dioxide in the atmosphere. All research activities are focused on developing various technologies that are capable of converting sunlight into electricity with high efficiency and can be produced using a cost-effective process. One of such technologies is the CuIn[sub1-x]Ga[subx]Se[sub2] (CIGS) and its alloys that can be produced using cost-effective techniques and also exhibit high photo-conversion efficiency. The work presented here discusses some of the fundamental issues related to high volume production of CIGS thin film solar cells. Three principal issues that have been addressed in this work are effect of reduction in absorber thickness on device performance, micrononuniformity involved with amount of sodium and its effect on device performance and lastly the effect of working distance on the properties of molybdenum back contact. An effort has been made to understand the effect of absorber thickness on PV parameters and optimize the process parameters accordingly. Very thin (<1 [micro]m) absorber film were prepared by selenization using metallorganic selenium source in a conventional furnace and by RTP using Se vapor. Sulfurization was carried out using H2S gas. Devices with efficiencies reaching 9% were prepared for very thin (<1 [micro]m) CIGS and CIGSeS thin films. It was shown through this work that the absorber thickness reduction of 64% results in the efficiency drop of only 32%. With further optimization of the reaction process of the absorber layer as well as the other layers higher efficiencies can be achieved. The effect of sodium on the device performance is experimentally verified in this work. To the best of our knowledge the detrimental effect of excess sodium has been verified by experimental data and effort has been made to correlate the variation in PV parameter to theoretical models of effect of sodium. It has been a regular practice to deposit thin barrier layer prior to molybdenum deposition to reduce the micrononuniformities caused due to nonuniform out diffusion of sodium from the soda lime glass. However, it was proven in this work that an optimally thick barrier layer is necessary to reduce the out diffusion of sodium to negligible quantities and thus reduce the micrononuniformities. Molybdenum back contact deposition is a bottleneck in high volume manufacturing due to the current state of art where multi layer molybdenum film needs to be deposited to achieve the required properties. In order to understand and solve this problem experiments were carried out. The effect of working distance (distance between the target and the substrate) on film properties was studied and is presented in this work. During the course of this work efforts were taken to carry out a systematic and detailed study of some of the fundamental issues related to CIGS technology and particular for high volume manufacturing of CIGS PV modules and lay a good foundation for further improvement of PV performance of CIGS thin film solar cells prepared by the two step process of selenization and sulfurization of sputtered metallic precursors.ID: 030423396; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2010.; Includes bibliographical references (p. 108-116).
Ph.D.
Doctorate
Department of Electrical Engineering and Computer Science
Engineering and Computer Science
40
Wilson, James. „Production, control and actuation of micron-sized particles in a microfluidic T-junction“. Honors in the Major Thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/934.
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This research is directed towards understanding the mechanisms associated with the manufacture of solid microspheres less than 100 [micrometers], from liquid droplets with nanosuspensions in a microfluidic T-junction, which are heated downstream of the channel. Preliminary material characterization tests on colloidal suspensions of alumina and copper oxide demonstrate promising temperature dependent viscosity results indicating solidification in the temperature range of 40°C-50°C. The solidification mechanism is referred to as Temperature Induced Forming and is described by polymeric bridges formed between nanoparticles in suspension at elevated temperatures, resulting in a solid structure. The polymer network results from the ionization of alumina at elevated temperatures whereby polymeric binders adhere to newly formed charged sites on the alumina particle. This study aims to investigate the aspects of manufacturing microstructures in microfluidic Tjunctions, droplet morphology, size and frequency of production. Preliminary low solid concentration experiments (1%-10% volume concentration of alumina in H2O) have indicated solidification and a regression in droplet diameter when heated near the saturation temperature of the water used to disperse the particles. The microstructures from this solidification process are uniform and are estimated to be 30 [micrometers] in size.B.S.M.E.
Bachelors
Mechanical, Material and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering
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Souto, Maria Veronilda Macedo. „S?ntese e caracteriza??o de CuNb2O6 e CuNbC atrav?s de rea??o s?lido- s?lido e g?s- s?lido a baixa temperatura“. Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12825.
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The refractory metal carbides have proven important in the development of engineering materials due to their properties such as high hardness, high melting point, high thermal conductivity and high chemical stability. The niobium carbide presents these characteristics. The compounds of niobium impregnated with copper also have excellent dielectric and magnetic properties, and furthermore, the Cu doping increases the catalytic activity in the oxidation processes of hydrogen. This study aimed to the synthesis of nanostructured materials CuNbC and niobium and copper oxide from precursor tris(oxalate) oxiniobate ammonium hydrate through gas-solid and solid-solid reaction, respectively. Both reactions were carried out at low temperature (1000?C) and short reaction time (2 hours). The niobium carbide was produced with 5 % and 11% of copper, and the niobium oxide with 5% of copper. The materials were characterized by X-Ray Diffraction (XRD), Rietveld refinement, Scanning Electron Microscopy (SEM), X-Ray Fluorescence Spectroscopy (XRF), infrared spectroscopy (IR), thermogravimetric (TG) and differential thermal analysis (DTA , BET and particle size Laser. From the XRD analysis and Rietveld refinement of CuNbC with S = 1.23, we observed the formation of niobium carbide and metallic copper with cubic structure. For the synthesis of mixed oxide made of niobium and copper, the formation of two distinct phases was observed: CuNb2O6 and Nb2O5, although the latter was present in small amounts
Os carbetos de metais refrat?rios t?m se revelado importantes no desenvolvimento de materiais de engenharia devido as suas propriedades, tais como: alta dureza, alto ponto de fus?o, alta condutividade t?rmica e alta estabilidade qu?mica. O carbeto de ni?bio apresenta essas caracter?sticas. Os compostos de ni?bio impregnados com cobre tamb?m possuem excelentes propriedades diel?tricas e magn?ticas e, al?m disso, a dopagem com Cu aumenta a atividade catal?tica em processos de oxida??o de hidrog?nio. Este trabalho teve como objetivo a s?ntese dos materiais CuNbC e ?xido de ni?bio e cobre nanoestruturados a partir do precursor tris(oxalato)oxiniobato de am?nio hidratado, atrav?s de rea??o g?s-s?lido e s?lido-s?lido, respectivamente. Para ambos, as rea??es foram realizadas a baixa temperatura (1000?C) e curto tempo de rea??o (2 horas). O carbeto de ni?bio foi produzido com 5% e 11% de cobre e o ?xido de ni?bio e cobre com 5% de cobre. Os materiais obtidos foram caracterizados atrav?s dos ensaios de Difra??o de Raios X (DRX), Refinamento Rietveld, Microscopia Eletr?nica de Varredura (MEV), Espectroscopia por Fluoresc?ncia de Raios-X (FRX), Espectroscopia de Infravermelho (IV), Termogravim?trica (TG), An?lise Termodiferencial (DTA), BET e granulometria a Laser. A partir das an?lises de DRX e do refinamento Reitiveld para o CuNbC com S= 1,23, observou-se a forma??o do carbeto de ni?bio e cobre puro com estrutura c?bica. Na s?ntese realizada do ?xido misto de ni?bio e cobre correu a forma??o de duas fases distintas: CuNb2O6 e Nb2O5, embora a ?ltima tenha sido formada em pequena quantidade
2020-01-01
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OLIVEIRA, Janaína Cortêz de. „Caracterização de isolados de Xanthomonas citri subsp. malvacearum e redução da mancha-angular do algodoeiro mediada pelo silício“. Universidade Federal Rural de Pernambuco, 2010. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/6601.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The bacterial blight caused by Xanthomonas citri subsp. malvacearum (Xcm) is the most important bacterial disease of cotton in the Middle-West and Northeast Regions of Brazil. The variability of a population formed by 100 Xcm strains obtained from commercial fields in the states of Goiás, Mato Grosso, Mato Grosso do Sul and Bahia, Brazil, was analyzed based upon genetic and phenotypic characteristics. The enzymes amylase, lipase, cellulase and the polysaccharide levan were produced by all Xcm isolates while the caseinase was only produced by 20 strains. All strains induced hipersensitivity reaction in tomato leaves. The 100 strains were sensitive to copper oxychloride (1500 mg L-1), copper hidroxide (1614 mg L-1), oxytetracicline (600 mg L-1), oxytetracicline (90 mg L-1) + tribasic copper sulfate (1500 mg L-1) and oxytetracicline (76.6 mg L-1) + streptomycin sulfate (367.2 mg L-1), but resistant to kasugamycin (60 mg L-1). Among the eighteen tested antibiotics the strains presented variable reaction in relation to: nalidixic acid, amoxicillin, azithromycin, bacitracin, eritromicin, kanamycin, pefloxacin, tobramycin e vancomycin. Rep-PCR (REP, ERIC and BOX) showed the formation of five groups at 70% similarity level. Group I contained 98 strains, including the reference strain Xcm IBSBF1733, group II contained only two strains from Bahia and the other three groups included strains of Xanthomonas citri pv. anacardii, X. citri pv. mangiferaeindicae e X. axonopodis pv. spondiae used for comparison. This work also evaluated the effect of silicon (Si) on the bacterial blight of cotton control and the putative mechanisms involved in the resistance potentialized by this element were evaluated. Calcium silicate (CaSiO3) was incorporated into the soil at concentrations of 0.00, 0.25, 0.50, 1.50 and 3.00 g of SiO2 kg-1 soil 25 days before planting. Leaves of 33-day-old-plants were inoculated by infiltration with 0.5 mL suspension of Xcm (108 CFU ml-1). Components of resistance were evaluated every two days until 10 days after inoculation, at which point plant development and the accumulation of Si and Calcium (Ca) were also determined. H2O2 production and the activity of enzymes related to plant defenses were analyzed at 6, 12 and 24 hours after inoculation in plants +/-Si. In vitro inhibition of pathogen growth due to Si was also assessed. No significant difference was seen among the treatments regarding incubation period, disease incidence or inhibition of bacterial growth. However, with the application of 1.50 g of SiO2 kg-1 of soil, a reduction in severity (54.9%) was observed along with a reduction in the area under the disease progression curve (35.76%) and an increase in plant height (7.04%). There was no observable accumulation of Si in the cotton leaves. Levels of soluble proteins and H2O2 and activity of the enzymes SOD, APX, guaiacol peroxidase, PAL and b Glu were altered in the presence of Si (1.80 g SiO2 kg-1). Thus based on the genetic and phenotypic characteristics studied we conclude that the population of 100 Xcm strains presents low variability, and that the reduction of cotton bacterial blight severity mediated by Si is probably associated to the characteristic events of induced resistance observed.
A mancha-angular, causada por Xanthomonas citri subsp. malvacearum (Xcm), é a principal doença bacteriana do algodoeiro no Centro-Oeste e Nordeste do Brasil. A variabilidade de uma população de 100 isolados de Xcm, oriundos de plantas com sintomas típicos de mancha-angular em áreas produtoras de algodoeiro dos estados de Goiás, Mato Grosso, Mato Grosso do Sul e Bahia, Brasil, foi analisada com base em características fenotípicas e genéticas. As enzimas amilase, lipase e celulase e o polissacarídeo levana foram produzidos por todos os isolados de Xcm, enquanto a caseinase foi produzida apenas por 20 isolados. Todos os isolados induziram reação de hipersensibilidade em folhas de tomateiro. Os 100 isolados foram sensíveis a oxicloreto de cobre (1500 mg l-1), hidróxido de cobre (1614 mg l-1), oxitetraciclina (600 mg l-1), oxitetraciclina (90 mg l-1) + sulfato tribásico de cobre (1500 mg l-1) e oxitetraciclina (76,6 mg l-1) + sulfato de estreptomicina (367,2 mg l-1), e resistentes a casugamicina (60 mg l-1). Dentre os 18 antibióticos testados, os isolados bacterianos apresentaram reação variável a nove: ácido nalidíxico, amoxicilina, azitromicina, bacitracina, eritromicina, kanamicina, pefloxacina, tobramicina e vancomicina. Rep-PCR (REP, ERIC e BOX) revelou a formação de cinco grupos ao nível de 70% de similaridade, sendo o grupo I constituído de 98 isolados, incluindo o isolado referência de Xcm IBSBF1733, o grupo II, formado apenas por dois isolados oriundos da Bahia e os três outros grupos por isolados de X. citri pv. anacardii, X. citri pv. mangiferaeindicae e X. axonopodis pv. spondiae utilizados para comparação. Neste trabalho também foi avaliado o efeito do silício (Si) no controle da mancha-angular do algodoeiro, e os possíveis mecanismos envolvidos na resistência potencializada por este elemento. O silicato de cálcio (CaSiO3) foi incorporado ao solo nas doses de 0,00; 0,25; 0,50; 1,50 e 3,00 g de SiO2 kg-1 de solo 25 dias antes do plantio. Plantas com 33 dias tiveram as folhas inoculadas por infiltração com 0,5 mL de suspensão de Xcm (108 UFC ml-1). Os componentes da resistência foram avaliados a cada dois dias até 10 dias após a inoculação, quando o desenvolvimento da planta e o acúmulo de Si e Ca foram também determinados. Foram ainda analisadas a atividade de enzimas relacionadas à defesa vegetal e a produção de H2O2 às 6, 12 e 24 h após a inoculação em plantas +/-Si e a inibição in vitro do crescimento do patógeno. Não foi verificada diferença significativa entre os tratamentos quanto ao período de incubação, incidência da mancha-angular e inibição do crescimento da bactéria. Com a aplicação da dose 1,50 g SiO2 kg-1 de solo, observou-se redução da severidade (54,9%), da área abaixo da curva de progresso da doença (35,76%) e aumento na altura das plantas (7,04%). Não foi verificado acúmulo de Si nas folhas de algodoeiro. Níveis de proteínas solúveis e H2O2 e atividade das enzimas SOD, APX, POX, PAL e GLU foram alterados na presença do Si (1,80 g SiO2 kg-1). Com base nas características fenotípicas e genéticas analisadas, conclui-se que a população de 100 isolados de Xcm estudada apresenta baixa variabilidade e que a redução da severidade da mancha-angular do algodoeiro mediada por Si está provavelmente associada aos eventos característicos de indução de resistência observados.
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Lima, Maria Jos? Santos. „S?ntese e caracteriza??o de TaC e ?xido misto de t?ntalo e cobre nanoestruturados a partir do precursor ox?lico de t?ntalo atrav?s de rea??es g?s-s?lido e s?lido-s?lido a baixa temperatura“. Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12797.
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Previous issue date: 2013-06-20Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
The research and development of nanostructured materials have been growing significantly in the last years. These materials have properties that were significantly modified as compared to conventional materials due to the extremely small dimensions of the crystallites. The tantalum carbide (TaC) is an extremely hard material that has high hardness, high melting point, high chemical stability, good resistance to chemical attack and thermal shock and excellent resistance to oxidation and corrosion. The Compounds of Tantalum impregnated with copper also have excellent dielectric and magnetic properties. Therefore, this study aimed to obtain TaC and mixed tantalum oxide and nanostructured copper from the precursor of tris (oxalate) hydrate ammonium oxitantalato, through gas-solid reaction and solid-solid respectively at low temperature (1000 ? C) and short reaction time. The materials obtained were characterized by X-ray diffraction (XRD), Rietveld refinement, Scanning Electron Microscopy (SEM), Spectroscopy X-Ray Fluorescence (XRF), infrared spectroscopy (IR), thermogravimetric (TG), thermal analysis (DTA) and BET. Through the XRD analyses and the Reitiveld refinement of the TaC with S = 1.1584, we observed the formation of pure tantalum carbide and cubic structure with average crystallite size on the order of 12.5 nanometers. From the synthesis made of mixed oxide of tantalum and copper were formed two distinct phases: CuTa10O26 and Ta2O5, although the latter has been formed in lesser amounts
A pesquisa e o desenvolvimento de materiais nanoestruturados v?m crescendo significativamente nos ?ltimos anos. Estes materiais apresentam propriedades significativamente modificadas em compara??o ?s dos materiais convencionais, devido ?s dimens?es extremamente reduzidas dos cristalitos. O carbeto de t?ntalo (TaC) ? um material extremamente duro, apresentando elevada dureza, elevado ponto de fus?o, elevada estabilidade qu?mica, boa resist?ncia ao ataque qu?mico e choque t?rmico e excelente resist?ncia ? oxida??o e corros?o. Os compostos de T?ntalo impregnados com Cobre tamb?m possuem excelentes propriedades diel?tricas e magn?ticas. Desta forma este trabalho teve como objetivo a obten??o de TaC e do ?xido misto de t?ntalo e cobre nanoestruturado a partir do precursor tris(oxalato)oxitantalato de am?nio hidratado, atrav?s de rea??o g?s-s?lido e s?lido-s?lido, respectivamente,a baixa temperatura (1000?C) e curto tempo de rea??o. Os materiais obtidos foram caracterizados atrav?s de Difra??o de Raios-X (DRX), Refinamento Rietveld, Microscopia Eletr?nica de Varredura (MEV), Espectroscopia por Fluoresc?ncia de Raios-X (FRX), Espectroscopia de Infravermelho (IV), Termogravim?trica (TG), Analise Termodiferencial (DTA) e BET. Atrav?s das analises de DRX e do refinamento Reitiveld para o TaC com S= 1,1584 observou-se a forma??o do carbeto de t?ntalo puro com estrutura c?bica e tamanho m?dio de cristalitos na ordem de 12,5 nan?metros. Para a s?ntese realizada do ?xido misto de t?ntalo e cobre houve a forma??o de duas fases distintas: CuTa10O26 e Ta2O5, embora esta ?ltima tenha sido formada em menor quantidade
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SALOMONE, FABIO. „Addressing the challenges of the Power-to-Fuel technologies from a catalyst development and techno-economic point of view“. Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2907012.
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Lenoble, Marie-Anne. „Dépot électrolytique de CoFeCu, matériau magnétique doux de forte induction pour tetes magnétiques“. Grenoble INPG, 1995. http://www.theses.fr/1995INPG0156.
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L'alliage cofecu a ete choisi pour son aptitude a repondre aux criteres que doit remplir tout nouveau materiau magnetique doux des tetes magnetiques. Une etude electrochimique des phenomenes de depot, a permis de preciser les parametres operatoires qui influent sur la composition de l'alliage. Des depots sont d'abord realises sur de grandes surfaces pour les caracterisations magnetiques et structurales: un lien est etabli entre la composition donnant les proprietes optimales et la structure de l'alliage. Les depots dans des caissons de taille micronique pour les tetes magnetiques couches minces sont ensuite etudies pour optimiser l'obtention de la piece polaire superieure. Le depot est enfin realise sur de vraies tetes qui sont ensuite testees. Les resultats obtenus sont encourageants car l'overwrite et le wiggle sont bien ameliores. La tenue en frequence pourrait etre amelioree en appliquant un champ magnetique plus eleve pendant le depot. Des ajouts de molybdene dans l'alliage ont conduit a de meilleures proprietes magnetiques laissant esperer une reponse encore meilleure de la tete
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EndahingPertiwi, Mustika, und 貝達心. „Synthesis of Titania Coated Copper–Zinc Oxide Nanopowdersas Dark Color Pigment with High Near-Infra Red Reflective Property“. Thesis, 2011. http://ndltd.ncl.edu.tw/handle/48633211432515916409.
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Weng, De-Feng, und 翁得峰. „Cloning, expression and characterization of the red porgy copper/zinc superoxide dismutase and cloning of the zebrafish 12-lipoxygenase“. Thesis, 2001. http://ndltd.ncl.edu.tw/handle/35879762510350618191.
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碩士國立海洋大學
水產生物技術研究所
89
Abstract A full-length cDNA clone of 774 bp encoding a putative copper / zinc-superoxide dismutase ( Cu/Zn-SOD ) from red porgy (Pagrus major ) was cloned by PCR approach. Nucleotide sequence analysis of this cDNA clone revealed that it comprises a complete epenreading frame coding for 154 amino acid residues. The deduced amino acid sequence showed high similarity (53~91%) with the sequences of the Cu/Zn-SOD from other species. Computer analysis of the residues required for coordinating copper ( His-47, 49, 64 and 121 ) and zinc ( His-64, 72, 81 and Asp-84 ), as well as the two cysteines ( 58 and 147 ) that form a single disulfide bond, were well conserved among all reported Cu/Zn-SOD sequences. To further characterize the red porgy Cu/Zn-SOD, the coding region was subcloned into an expression vector, pET-20b (+), and transformed into Escherichia coli BL21(DE3). The expression of the Cu/Zn-SOD was confirmed by enzyme activity stained on a native gel and purified by Ni2+- nitrilotriacetic acid Sepharose superflow. Dimer was the major form of the enzyme in equilibrium. The dimerization of the enzyme was inhibited under acidic pH (below 4.0 or higher than 10.0). The enzyme retained about 75% activity after heating 70 ℃for 10 min. The half-life was 15 min and the inactivation rate constant (Kd) was 9.64×10-2 min-1 at 70℃. About 30% protein of the enzyme was dissociated into monomer from under 4% SDS or 1M imidazole. The enzyme was much more resistant to trypsin attack than chymotrypsin.
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Stockham, Katherine. „Antioxidants in food systems: influencing factors“. Thesis, 2017. https://vuir.vu.edu.au/37865/.
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For well over 20 years the Oxygen Radical Absorbance Capacity (ORAC) assay has been an important research tool in identifying antioxidant candidates in food and serum samples. The ORAC value is derived from a series of fluorescence intensity measurements taken over a period of time, usually a few hours. The kinetics of this reaction is controlled by the sustained release of peroxyl radicals at 37°C by an azo compound (AAPH). The peroxyl radicals attack the fluorescent probe causing a gradual decrease in fluorescence intensity. Ultimately, the test yields fluorescence decay curves over time, with the presence of any antioxidants in a sample having a protective effect, delaying probe decay and resulting in a greater area under the decay curve. This forms the basis of the ORAC measurement.
Concerns have been raised about the applicability of this assay, chemical interferences influencing the data, and the use of ORAC values to attribute health benefits of foods. In an effort to curb misrepresentation of health benefits from ORAC data, the USDA retracted its ORAC database in 2012 and published a statement by Dr Ronald Prior, a founding researcher for the ORAC assay. The explanatory statement by Dr Prior identified the misapplication of ORAC values and misleading perceived health benefits as major reasons for withdrawal of the database.
Despite this, ORAC remains a popular assay, and the method is widely used as a product development and marketing tool. Some researchers have reported that ORAC values can be influenced by factors such as choice of solvent, chemical constituents in matrices, and pH conditions. However, little has been published on antioxidant synergies in food systems and their contribution to the ORAC value.
Given the predisposition of the assay to interferences, a better understanding of antioxidant synergies is necessary to understand the contributing factors to measurement in real foods, and also to determine how these values may be manipulated. With the USDA caution in mind, this research was carried out to systematically investigate the factors influencing the ORAC measurement and its interpretation.
Firstly, an alternative mode of reporting antioxidant activity to consumers on product labeling was proposed. Calculations needed to convert ORAC units from μM Trolox equivalents (μM T.E/kg or μM T.E/L) to mass units (g T.E/kg or g T.E/L) of Trolox equivalents per kg or per L of foodstuff are provided. We propose that mass units are less misleading to consumers, by not reporting very large and impressive-looking values when a simple conversion reveals most of them to be much more modest when viewed as a mass of vitamin E equivalent. For example, the antioxidant activity of blueberries when measured by the ORAC assay was equivalent to over 71,000 μM of Trolox equivalents. When converted, the blueberries can be said to have the same antioxidant activity as 17.9g of vitamin E per kg of fruit (17.9g T.E/kg). This new mode of reporting was successfully applied to a range of commodities including fruit, confection and beverages.
Influencing factors, including environmental conditions, role of additives and nanoparticles and interactions between classes of chemical constituents were all investigated. Environmental conditions, specifically rainfall, were found to influence the levels of antioxidant compounds/bioactives in Australian wines. Six chemical constituents were identified as warranting further investigation; namely 6-methylcoumarin, protocatechuic acid, vanillic acid, p-coumaric acid, rutin and chlorogenic acid. Significant differences were also observed between the antioxidant capacity of wines by in vitro ORAC and ex vivo CAA-RBC assays, where wines with similar ORAC values had vastly different bioavailability and activity in the cellular system.
Amino acids and CuNPs additives were found to greatly influence the antioxidant measurements of “superfoods”. Results indicated strong enhancements and synergies related to the properties of the amino acids and complexes formed with Cu(I) and essentially matrix independent.. The order of antioxidant enhancement in bilberry, coffee berry, and apple concentrates was Tryptophan > Tyrosine > Methionine ≥ Histidine ≥ 4-Hydroxyproline. This order was also consistent with the order of calculated bond dissociation energies (BDEs), reflecting the inherent antioxidant potentials of the amino acids studied. Density Functional Theory (DFT) was used to support a proposed “substrate zone” and “antioxidant zone” postulate for amino acids and related additives and this concept assists in demonstrating potential mechanisms involved in achieving such extraordinary enhancements and synergies. Histidine was used as a model system for DFT calculations, and allowable species had homolytic BDEs ranging from high (deactivated) to very low (activated), in the case of species (b) the BDE was at a level well below that of vitamin E, making it an excellent and potentially potent antioxidant. DFT calculations revealed that the histidine-Cu(I) complex had a comparable BDE to that of Trolox, again demonstrating how interactions between chemical constituents can influence, and in this case enhance antioxidant activity measurements.
Synergies and antagonisms were also reported for eight classes of chemical constituents typically found in navel oranges. These mixtures were prepared based on the levels reported in nutritional data tables, and analyzed by ORAC and CAA-RBC assays. A correlation analysis revealed that the ORAC and CAA-RBC data did not correlate overall, however distinct clustering and several interesting outliers were noted. Cluster (a) had low ORAC and low CAA-RBC values, involving combinations of preservatives, sugars and CuNPs. Cluster (b) had low to moderate responses in both assays, and was made up primarily of vitamins in combination with CuNPs, preservatives, sugars and flavonoids. Cluster (c) was dominated by phenolics and their interactions with a number of groups, which gave high antioxidant activity in both ORAC and CAA-RBC assays, and amino acids are the main contributors in cluster (d). Organic acids featured in both outliers, firstly with a high antioxidant activity in both assays when combined with polyphenolics, and secondly as having an auto-oxidation effect in the CAA-RBC assay but a high ORAC value when analysed individually. Antioxidant activities of individual mixtures and combinations of classes of compounds showed antagonism/suppression of antioxidant activity between sugars and vitamins, and between polyphenolics and flavonoids in the ORAC assay. However, these same solutions resulted in antioxidant synergy in the CAA-RBC assay. In fact, the auto-oxidation effect of organic acids was reversed and synergies were noted in interaction with polyphenolics. A number of synergisms ex vivo involved polyphenolics in combination with other constituents such as vitamins, the amino acid Tryptophan, preservatives and CuNPs. These findings support the postulate that interactions at the “substrate zone” are influencing factors of antioxidant capacity at the molecular level. Computational chemistry was used to postulate mechanisms for antioxidant synergy, activation and deactivation of phenolic O-H groups, using quercetin and (-)-epicatechin-3-gallate as examples.
It was concluded that factors including rainfall, amino acid and CuNPs addition, and interactions between common classes of food constituents influenced antioxidant activity in food systems. Computational chemical calculations were used to postulate mechanisms for antioxidant enhancement and synergy, a major influencing factor in antioxidant measurements. This research describes the potential for unlocking new and powerful antioxidant synergies in food systems, nutrition and health and the medical/pharmaceutical fields.
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Young, Mikaeel. „Mixed Valence Copper(Cu)/Silica Nanocomposite: Synthesis, Characterization and Systematic Antimicrobial Studies“. Master's thesis, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/6208.
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Copper (Cu) compounds are widely used as effective agricultural bactericides. Continuous use of these materials has led to Cu accumulation in soil over time. The United States Environmental Protection Agency (US EPA) is concerned about potential Cu contamination in the environment. Improving biocidal efficacy of Cu is an attractive alternative, allowing reduction of Cu amount per application. In this research, we focused on making water-soluble mixed-valence Copper/Silica composite nanogel (CuSiNG) material. The objective is to improve the efficacy of Cu by manipulating Cu valence states. It has been shown in the literature that Cu (0) and Cu (I) states are more potent that Cu (II) states in terms of their antimicrobial efficacy. It is hypothesized that mixed valence Cu will exhibit improved efficacy over Cu (II). A water-soluble mixed valence Cu/silica nanogel (MV-CuSiNG) composite has been synthesized and characterized. Structure, morphology, crystallinity and composition of the MV-CuSiNG material was characterized using High-Resolution Transmission Electron Microscopy (HRTEM), HRTEM Selected Area Electron Diffraction (SAED) and X-ray Photoelectron Spectroscopy (XPS). Amount of Cu loading in MV-CuSiNG composite material was estimated by Atomic Absorption Spectroscopy (AAS). To confirm presence of Cu (I) in the MV-CuSiNG material, Neocuproine (Nc, a Cu (I) specific chelator) assay was used. Antimicrobial efficacy of MV-CuSiNG and CuSiNG was evaluated against X.alfalfae, B.subtilis and E.coli using Kocide 3000 (“Insoluble Cu (II)” compound), Copper sulfate (“Soluble Cu (II)” compound) and Cuprous chloride (Copper (I) compound) as positive controls and silica “seed” particles (without Cu loading) as negative control. Antimicrobial studies included observing bacterial growth inhibition and determining the Minimum Inhibitory Concentration (MIC). Improved antimicrobial efficacy was observed in MV-CuSiNG when compared to CuSiNG and other controls. For the assessment of plant safety of MV-CuSiNG and CuSiNG materials, phytotoxicity studies were conducted using Vinca sp and Hamlin orange under environmental conditions. It was observed that MV-CuSiNG material was safe to plants at commercially used (standard) spray application rate.M.S.
Masters
Molecular Biology & Micro
Medicine
Biotechnology; Professional Science Master's Track
50
Yang, Chengyu. „First Principle Studies of Cu-Carbon Nanotube Hybrid Structures with Emphasis on the Electronic Structures and the Transport Properties“. Doctoral diss., 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/6207.
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Carbon nanotubes have been regarded as ideal building blocks for nanoelectronics and multifunctional nanocomposites due to their exceptional strength, stiffness, flexibility, as well as their excellent electrical properties. However, carbon nanotube itself has limitations to fulfill the practical application needs: 1) an individual carbon nanotube has a low density of states at the Fermi level, and thus its conductivity is only comparable to moderate metals but lower than that of copper. 2) Metallic and semiconducting nanotubes are inherently mixed together from the synthesis, and the selection/separation is very difficult with very low efficiency. 3) Carbon nanotubes alone cannot be used in practical application and a bonding material is normally needed as the join material for actual devices.
In this work, we fundamentally explored the possibility that metals (Cu, Al) could tailor carbon nanotube's electronic structure and even transit it from semiconducting to metallic, thus skipping the selection between the metallic and the semiconducting CNTs. We also found out a novel way to enhance a semiconducting CNT system's conductance even better than that of a metallic CNT system. All these researches are done under density functional theory (DFT) frame in conjunction with non-equilibrium Green functions (NEGF).
At first we studied the adsorbed copper's influence on the electronic properties of CNT (10, 0) and CNT (5, 5). Results indicate that both the Density of States (DOS) and the transmission coefficients of CNT (5,5) /Cu have been increased. For CNT (10,0)/Cu, the band gap has been shrank, which means the improved conducting properties by the incorporation of copper .
As a further case, semiconductor SWCNT (10, 0) with more adsorbed copper chains outside has been studied. 1, 4, 5 and 6 Cu chains have been added onto the carbon nanotube (10,0), and the adsorption of 6 Cu chains finally lead to the transform of the system from semiconducting to metallic.
Considering the confining effect, the case that Cu filled into CNT (10, 0) is also studied. It is found that the filled copper chains could modify the system to be metallic more efficiently than the adsorbed Cu chain.
Similarly, Al adsorbed on CNT (10, 0) is also studied, and it is found that Al has a better efficiency than copper in tuning the semiconducting CNT to metallic. The existing chemical bonds between the CNT and Al atoms may account for this higher efficiency. In addition, the resultant conductivity of the Al/CNT system is better than that of Cu/CNT system.
The Cu/CNT (5,5)+Cu/Cu junction, as another realistic device setup, has been studied in terms of the conductance. The results show that the incorporation of Cu would enhance the conductance of the Cu/CNT/Cu system due to the interaction between Cu and the CNT.Ph.D.
Doctorate
Materials Science Engineering
Engineering and Computer Science
Materials Science and Engineering