Literatura académica sobre el tema "Copper thiolate"

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Artículos de revistas sobre el tema "Copper thiolate"

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Stillman, Martin J., Anthony Presta, Ziqi Gui y De-Tong Jiang. "Spectroscopic Studies of Copper, Silver and Gold-Metallothioneins". Metal-Based Drugs 1, n.º 5-6 (1 de enero de 1994): 375–94. http://dx.doi.org/10.1155/mbd.1994.375.

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Metallothionein is a ubiquitous protein with a wide range of proposed physiological roles, including the transport, storage and detoxification of essential and nonessential trace metals. The amino acid sequence of isoform 2a of rabbit liver metallothionein, the isoform used in our spectroscopic studies, includes 20 cysteinyl groups out of 62 amino acids. Metallothioneins in general represent an impressive chelating agent for a wide range of metals. Structural studies carried out by a number of research groups (using H1 and Cd113 NMR, X-ray crystallography, more recently EXAFS, as well as optical spectroscopy) have established that there are three structural motifs for metal binding to mammalian metallothioneins. These three structures are defined by metal to protein stoichiometric ratios, which we believe specifically determine the coordination geometry adopted by the metal in the metal binding site at that metal to protein molar ratio. Tetrahedral geometry is associated with the thiolate coordination of the metals in the M7-MT species, for M = Zn(II), Cd(II), and possibly also Hg(II), trigonal coordination is proposed in the M11-12-MT species, for M = Ag(I), Cu(I), and possibly also Hg(II), and digonal coordination is proposed for the metal in the M17-18-MT species for M = Hg(II), and Ag(I). The M7-MT species has been completely characterized for M = Cd(II) and Zn(II). Cd113 NMR spectroscopic and x-ray crystallographic data show that mammalian Cd7-MT and Zn7-MT have a two domain structure, with metal-thiolate clusters of the form M4(Scys)11 (the α domain) and M3(Scys)9 (the β domain). A similar two domain structure involving Cu6(Scys)11 (α) and Cu6(Scys)9 (β) copper-thiolate clusters has been proposed for the Cu12-MT species. Copper-, silver- and gold-containing metallothioneins luminesce in the 500-600 nm region from excited triplet, metal-based states that are populated by absorption into the 260-300 nm region of the metal-thiolate charge transfer states. The luminescence spectrum provides a very sensitive probe of the metal-thiolate cluster structures that form when Ag(I), Au(I), and Cu(I) are added to metallothionein. CD spectroscopy has been used in our laboratory to probe the formation of species that exhibit well-defined three-dimensional structures. Saturation of the optical signals during titrations of MT with Cu(I) or Ag(I) clearly show formation of unique metal-thiolate structures at specific metal:protein ratios. However, we have proposed that these M=7, 12 and 18 structures form within a continuum of stoichiometries. Compounds prepared at these specific molar ratios have been examined by X-ray Absorption Spectroscopy (XAS) and bond lengths have been determined for the metal-thiolate clusters through the EXAFS technique. The stoichiometric ratio data from the optical experiments and the bond lengths from the XAS experiments are used to propose structures for the metal-thiolate binding site with reference to known inorganic metal-thiolate compounds.
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Felix, K. y U. Weser. "Release of copper from yeast copper-thionein after S-alkylation of copper-thiolate clusters". Biochemical Journal 252, n.º 2 (1 de junio de 1988): 577–81. http://dx.doi.org/10.1042/bj2520577.

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Our knowledge on the release of copper from Cu-thionein in biological systems is limited. Other than oxidative cleavage or direct transfer, the possibility of an alkylation mechanism seemed attractive. Iodoacetamide and methyl methanesulphonate were successfully employed to alkylate the Cu-thiolate sulphur atom of homogeneous Cu(I)-thionein from yeast. The alkylation caused a weakening of the Cu-S bonding, which led to the release of copper. After equilibrium dialysis a proportion of the released copper was found in the dialysis buffer. When iodoacetamide was used carboxymethylcysteine was detected in the protein hydrolysate. A 10-fold molar excess over cysteine was sufficient for complete alkylation, which could be conveniently monitored by c.d. at 328 and 359 nm. The reaction proceeded under both aerobic and anaerobic conditions. E.p.r. measurements of Cu2+ revealed unequivocally the complete cleavage of the Cu-thiolate bonding in less than 5 h. It is possible that this mode of copper release might be of relevance to the molecular transport of this biochemically important transition metal.
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Rungthanaphatsophon, Pokpong, Charles L. Barnes y Justin R. Walensky. "Copper(i) clusters with bulky dithiocarboxylate, thiolate, and selenolate ligands". Dalton Transactions 45, n.º 36 (2016): 14265–76. http://dx.doi.org/10.1039/c6dt02709a.

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Compel, W. Scott. "Metallogels through glyme coordination". Dalton Transactions 45, n.º 11 (2016): 4509–12. http://dx.doi.org/10.1039/c6dt00255b.

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Neuba, Adam, Roxana Haase, Wolfram Meyer-Klaucke, Ulrich Flörke y Gerald Henkel. "A Halide-Induced Copper(I) Disulfide/Copper(II) Thiolate Interconversion". Angewandte Chemie International Edition 51, n.º 7 (10 de enero de 2012): 1714–18. http://dx.doi.org/10.1002/anie.201102714.

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Espinoza-Cara, Andrés, Ulises Zitare, Damián Alvarez-Paggi, Sebastián Klinke, Lisandro H. Otero, Daniel H. Murgida y Alejandro J. Vila. "Engineering a bifunctional copper site in the cupredoxin fold by loop-directed mutagenesis". Chemical Science 9, n.º 32 (2018): 6692–702. http://dx.doi.org/10.1039/c8sc01444b.

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Zhang, Meng-Juan, Hong-Xi Li, Hai-Yan Li y Jian-Ping Lang. "Copper(i) 5-phenylpyrimidine-2-thiolate complexes showing unique optical properties and high visible light-directed catalytic performance". Dalton Transactions 45, n.º 44 (2016): 17759–69. http://dx.doi.org/10.1039/c6dt03721f.

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Copper(i) 5-phenylpyrimidine-2-thiolate complexes exhibit intriguing luminescence properties and excellent visible light-directed catalytic activity towards aerobic oxidative hydroxylation of arylboronic acids.
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Brader, Mark L. y Michael F. Dunn. "Insulin stabilizes copper(II)-thiolate ligation that models blue copper proteins". Journal of the American Chemical Society 112, n.º 11 (mayo de 1990): 4585–87. http://dx.doi.org/10.1021/ja00167a090.

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Mroczka, Robert, Agnieszka Słodkowska, Agata Ładniak y Agnieszka Chrzanowska. "Interaction of Bis-(sodium-sulfopropyl)-Disulfide and Polyethylene Glycol on the Copper Electrodeposited Layer by Time-of-Flight Secondary-Ion Mass Spectrometry". Molecules 28, n.º 1 (3 de enero de 2023): 433. http://dx.doi.org/10.3390/molecules28010433.

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The interactions of the functional additives SPS (bis-(sodium-sulfopropyl)-disulfide) and polyethylene glycol (PEG) in the presence of chloride ions were studied by time-of-flight secondary-ion mass spectrometry (TOF-SIMS) in combination with cyclic voltammetry measurements (CV). The PEG, thiolate, and chloride surface coverages were estimated and discussed in terms of their electrochemical suppressing/accelerating abilities. The conformational influence of both the gauche/trans thiolate molecules, as well as around C-C and C-O of PEG, on the electrochemical properties were discussed. The contribution of the hydrophobic interaction of -CH2-CH2- of PEG with chloride ions was only slightly reduced after the addition of SPS, while the contribution of Cu-PEG adducts diminished strongly. SPS and PEG demonstrated significant synergy by significant co-adsorption. It was shown that the suppressing abilities of PEG that rely on forming stable Cu-PEG adducts, identified in the form C2H4O2Cu+ and C3H6OCu+, were significantly reduced after the addition of SPS. The major role of thiolate molecules adsorbed on a copper surface in reducing the suppressing abilities of PEG rely on the efficient capture of Cu2+ ions, diminishing the available copper ions for the ethereal oxygen of PEG.
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Kongsumrit, Pacharaporn y Soorathep Kheawhom. "Thermal Stability of Thiolate Self-Assembled Monolayers on Copper Surface". Advanced Materials Research 646 (enero de 2013): 18–23. http://dx.doi.org/10.4028/www.scientific.net/amr.646.18.

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The formation of self-assembled monolayers (SAMs) of organothiol is one of the excellent methods for corrosion protection. This work studies the thermal stability of thiolate SAMs coating on a copper surface. Three types of thiolate SAMs including 1-octanethiol (OTT), 2-ethylhexanethiol (2-EHT), and 2-phenylethanethiol (2-PET) are investigated. These chemicals are similar in terms of the chemical formula but different in chemical structure. Contact angle, AFM, FT-IR, XPS, and potentiodynamic polarization are used to analyze hydrophilic and hydrophobic features, roughness, decomposition of SAMs, and corrosion inhibition efficiency, respectively. The optimum condition of oxygen plasma treatment is determined. The results show that the optimum time for the treatment is 15 s. The oxygen plasma increases roughness of the Cu surface and induces the hydrophilic feature, which is suitable for SAMs to form on the Cu surface. The Cu surfaces coated by each SAMs are annealed at the temperature ranging from 25 to 250°C. The OTT is decomposed at 80°C while the 2-EHT is decomposed at 140°C. The 2-PET is not decomposed at 140°C, because the 2-PET consists of aromatic rings that are more stable than other functional groups in OTT and 2-EHT structures. These results also refer to improvement of thiolate bond stability aided by aromatic ring in the 2-PET molecule. All SAMs are completely decomposed at 250°C. In conclusion, the 2-PET is the most favorable in terms of thermal stability.
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Tesis sobre el tema "Copper thiolate"

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Branscombe, Neil D. J. "Studies on binuclear compartmental Schiff-base thiolate complexes". Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299550.

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Dicks, Andrew P. "Mechanistic studies of copper and thiolate ion induced S-nitrosothiol decompositions". Thesis, Durham University, 1997. http://etheses.dur.ac.uk/4703/.

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A detailed study concerning the aqueous decomposition characteristics of S-nitrosothiols in both the presence and absence of cupric ions was undertaken. Spectrophotometric measurements established that the true catalytic species generating nitric oxide from S-nitrosothiols is Cu(^+), formed by the reduction of copper(II) ions by thiolate, which is present as an impurity in solution. Introduction of the specific cuprous ion chelator neocuproine inhibited reaction, with the concentration of thiol in situ having a significant influence on the absorbance/time traces obtained. Under certain conditions thiolate ions clearly promoted S-nitrosothiol decomposition, whereas at times an opposite effect was noted. These results have been correlated with the reductive ability and chelation properties towards Cu(^2+) of each thiol in question. Structure/reactivity studies were extended further to include a range of S-nitrosated aromatic and heterocyclic thiols which generated the corresponding disulfides in distilled water yet reformed the appropriate thione at pH 7.4, along with nitric oxide in both media. A mechanism has been proposed which accounts for these observations. The reaction of S-nitrosothiols with cupric ions bound to biologically significant molecules such as amino acids, peptides and proteins was followed. Despite Cu(^2+) being chelated in this manner, S-nitrosothiol decomposition was apparent, albeit at a slower rate than that seen when copper(II) sulfate pentahydrate was utilised. Thiolate ions were capable of reducing Cu(^2+) Cu(^+) which was bound to such molecules suggesting a possible mechanism for nitric oxide formation from S-nitrosothiols in vivo. The blue copper protein ceruloplasmin also promoted NO generation under physiological conditions. A brief investigation into the direct reaction of thiolate ion with its corresponding S-nitrosothiol was also carried out. It was discovered that the major reaction product in this instance is ammonia and not nitric oxide, suggesting that a different copper-ion independent process is occurring involving direct interaction between the two species.
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馮潔媚 y Kit-mai Wendy Fung. "Luminescent polynuclear copper(I) and silver(I) complexes of bridging acetylides and related studies on copper(I) thiolates". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B3123687X.

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Fung, Kit-mai Wendy. "Luminescent polynuclear copper(I) and silver(I) complexes of bridging acetylides and related studies on copper(I) thiolates /". Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19102665.

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Petit, Samuel. "Structures de complexes dans le système (cuivre (II)-oxine-sulfoxine-eau), étude expérimentale et modélisation moléculaire de la cristallisation et de transitions de phases". Rouen, 1994. http://www.theses.fr/1994ROUES025.

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La résolution structurale d'une nouvelle variété anhydre d'oxinate de cuivre(II) (noté X) a été effectuée d'après le diagramme de diffraction X sur poudre. L'étude des filiations structurales et la prise en compte des données cinétiques, thermodynamiques et physico-chimiques ont mené à proposer un modèle pour les transitions solide-solide entre variétés dihydratées et anhydres d'oxinate de cuivre(II) (déshydratations et transitions polymorphiques). La résolution de structure sur monocristal et sur poudre de deux variétés hydratées de sulfoxinate de cuivre(II) a permis une étude par modélisation moléculaire de la nucléation homogène en solution aqueuse des variétés de structure connue. La croissance cristalline des sulfoxinates de cuivre(II) a été envisagée, conduisant à considérer la croissance d'une face associée à une tranche contenant deux molécules de conformations différentes. Le concept de sous-tranches non équivalentes par les opérations de symétrie du groupe d'espace est défini. Deux approches complémentaires ont été utilisées en vue d'expliquer l'influence de la sulfoxine sur l'évolution des oxinates de cuivre(II). D'une part, une étude des molécules d'oxine et de sulfoxine par les méthodes de chimie théorique a permis d'interpréter leur comportement en milieu aqueux. D'autre part, une étude expérimentale des complexes mixtes cuivre-oxine-sulfoxine a été entreprise
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Faulmann, Christophe. "Conducteurs derives de metaux de transition : complexes moleculaires, polymeres, oxydes de cuivre". Toulouse 3, 1988. http://www.theses.fr/1988TOU30160.

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Lin, Tso-Yu y 林佐諭. "Synthesis and Characterization of Penta-Copper/Silver-Thiolate Complex with Dithiol Ligand". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/56864843514774716078.

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碩士
高雄醫學大學
醫藥暨應用化學系碩士班
96
Copper is an essential element in all living organisms, serving as a cofactor for many important proteins and enzymes involved in electron transfer, oxidase and oxygenase activities and detoxification of oxygen radicals. The metallochaperone proteins deliver copper ions to specific physiological partners by direct protein-protein interactions. The Atx1-like chaperones transfer copper to intracellular copper transporters, and the CCS chaperones shuttle copper to copper, zinc superoxiede dismutase. In this work, we had synthesized a series of novel clusters containing copper(I) and silver(I) with the NS2 donor ligand. [PPh4][(C7H7NS2)3Cu5](12), [PPh4][(C8H9NS2)3Cu5] (13)and [Na][(C8H8S2)2Cu](14) were synthesized from their corresponding ligands.Thoes new compounds have been characterized by x-ray, mass and NMR spectroscopy. Those copper compounds and their transformation may help us to mimic the copper chaperone behavior.
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Lv, Xiaoyun. "Nanocrystalline materials for photovoltaic and nanomedicine applications". Doctoral thesis, 2018. http://hdl.handle.net/11562/977691.

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The aim of this thesis is to investigate the property of some typical photovoltaic and luminescent materials, and the possible application of these materials in the fields of solar energy, light emitting diode and biomedical imaging. Earth abundant and nontoxic material quaternary semiconductor copper zinc tin sulfide (CZTS) provides a photovoltaic capability with favorable optical and electronic properties. Crystalized into either kesterite or wurtzite phases in aqueous or organic solution, CZTS represents potential application in the field of solar cell. Low cost and easy producing material methylammonium lead halide perovskite CH3NH3PbX3 (X=I, Br and Cl) possess superior optoelectronic properties, it represents a great potential for a variety of applications, such as high-efficiency photovoltaic cells and light-emitting diodes, but the involvement of toxic element and the instability is a concerning issue. Some efforts are in progress in the recent years to replace it with nontoxic and stable varieties such as cesium tin halide (CsSnX3, X=Cl, Br, I) and the derivative Cs2SnX6 (X=Cl, Br, I). Ternary I–III–VI semiconductor CuInS2 possesses unique properties such as large Stokes shift and high absorption coefficient. By doping with lanthanide ion Gd3+, the dual-modal MRI contrast agent with good relaxivity and fluorescent probe-CuInS2@ZnS:Gd3+ quantum dots have been investigated. Synthesized in a very simple way, the copper thiolate compounds exhibit bright emission in the optical region of green, yellow to white. The life time of copper thiolate is in the range of micrometers. These compounds possess interesting mechanochromic and thermochromism luminescent properties. The α-NaYbF4, β-NaGdF4, β-NaGdF4:(Yb,Tm), orthorhombic KYb2F7, α-KGdF4, α-KGdF4:(Yb,Tm), MGdF4:Ce@MGdF4:Eu/Tb, MGdF4:(Yb,Tm)@MGdF4:Eu/Tb, and MGdF4:Yb,Tm@MGdF4:Eu/Tb@MGdF4:Ce (M: Na or K) NPs have been synthesized hydrothermally. Under 365-400 nm UV excitation, the Eu3+/Tb3+ doped NaYbF4, NaGdF4 and KGdF4 samples emit red or green light. Not only by longer UV excitation, MGdF4:Ce@MGdF4:Eu3+/Tb3+ NPs and MGdF4:Yb,Tm@MGdF4:Eu3+/Tb3+@MGdF4:Ce NPs can also emit red or green light under short UV excitation 254 nm by a Ce3+-> Gd3+ -> Eu3+/Tb3+ energy transfer process. Under 980 nm NIR laser excitation, these potassium and sodium based core shell and core-shell-shell NPs emit red or green light by an energy transfer process of Yb3+ -> Tm3+-> Gd3+ -> Eu3+/Tb3+. The potassium based NPs exhibit brighter UCPL than sodium based NPs.
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Capítulos de libros sobre el tema "Copper thiolate"

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Winge, D. R., C. T. Dameron, G. N. George, I. J. Pickering y I. G. Dance. "Cuprous-Thiolate Polymetalic Clusters in Biology". En Bioinorganic Chemistry of Copper, 110–23. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-6875-5_9.

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Janssen, Maurits D., David M. Grove y Gerard Van Koten. "Copper(I), Lithium, and Magnesium Thiolate Complexes: An Overview with Due Mention of Selenolate and Tellurolate Analogues and Related Silver(I) and Gold(I) Species". En Progress in Inorganic Chemistry, 97–149. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470166475.ch2.

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Pardasani, R. T. y P. Pardasani. "Magnetic properties of copper(II) complex with 2-pyridinemethane thiole-1-oxide". En Magnetic Properties of Paramagnetic Compounds, 528–29. Berlin, Heidelberg: Springer Berlin Heidelberg, 2017. http://dx.doi.org/10.1007/978-3-662-49202-4_252.

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Ulrich, Weser y Hartmann Hans-Jürgen. "Copper-Thiolate Proteins (Metallothioneins)". En Copper Proteins and Copper Enzymes, 151–74. CRC Press, 2018. http://dx.doi.org/10.1201/9781351070898-5.

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Masmoudi, Mohamed. "Infrared Characterization and Electrochemical Study of Silanes Grafted into Surface of Copper". En Thin Films [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.99782.

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The formation of a protective layer of tow silane coupling agents: γ -methacryloxypropyltrimethoxysilane (γ-MPS) or γ-aminopropyltriethoxysilane (γ-APS) on copper is studied by diffuse reflectance infrared spectroscopy (DRIFT), electrochemical (Potentiodynamic polarization) and gravimetric chemical (Weight loss) measurements. Dried in ambient conditions, the silane adsorbed on the copper subtract physically, however its protective action is not reliable. Thiolate and siloxane band formation ameliorate the protective action of the silanic layer on the surface of copper especially after curing process. Potentiodynamic polarization and Weight loss experiments show that the performances protective action of cured treatment (cured/Cu-silane) is higher than that of aging process (aged/Cu-silane).
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Drabowicz, J., P. Kiełbasiński y M. Mikołajczyk. "Reactions with Copper Thiolates". En Ene-X Compounds (X=S, Se, Te, N, P), 1. Georg Thieme Verlag KG, 2007. http://dx.doi.org/10.1055/sos-sd-033-00094.

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Actas de conferencias sobre el tema "Copper thiolate"

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Si, Xiuhua, Jinxiang Xi y Xihai Tao. "The Study of Calcium Carbonate Scaling on Low Energy Surfaces". En 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-22058.

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Scale deposition on heat transfer surfaces from water containing dissolved salts reduces the efficiency and performance of heat transfer equipments considerably. Scale deposition could be reduced through physical or chemical methods. In some cases, chemical methods are unacceptable, due to cost, contamination issues, etc. In these cases, physical methods are the only acceptable choices. Surface energy of the heat exchanger has been thought to be one important factor affecting the growth of fouling. Applying low energy surfaces to reduce scaling deposition is one of the effective physical methods. The formation and the characteristics of the calcium carbonate scaling on low energy surfaces have been studied in this paper. Copper and stainless steel surfaces were modified by micro-scale (μm thickness) PTFE (Poly-Tetrofluorethylene) films and nano-scale (nm thickness) thiolate SAMs (Self-Assembly Monolayers). The resulting surface energy of PTFE films and SAMs layers based on copper and stainless steel were significantly reduced compared with the original metal surfaces. To study the formation of the calcium carbonate scale, a recirculation cooling water system was used. The formation of the calcium carbonate scale on PTFE surfaces, SAMs surfaces, polished copper surfaces, and polished stainless steel surfaces were investigated respectively. The rate of calcium carbonate scale formation was decreased and the induction period was prolonged with the decrease of the heat transfer surface energy. The characteristics of the calcium carbonate scale formed on heat transfer surfaces with different surface energies was analyzed with fractal theory after taking photos with SEM (Scanning Electron Microscope). The fractal dimension values of the calcium carbonate scale on different heat transfer surfaces with different surface energies were calculated. The results showed that the fractal dimension values of calcium carbonate scale formed on lower energy PTFE and Cu-SAMs surfaces were greater than those that formed on higher energy Cu and stainless steel surfaces. Results of this study clearly indicated that the formation of calcium carbonate scaling on lower energy heat transfer surfaces is reduced.
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Si, Xiuhua, Sungmin Youn y Jinxiang Xi. "Reducing Scale Deposition by Surface Modification and Magnetic Water Treatment". En ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-12796.

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Scale deposition (or fouling) on metal surfaces from salt-containing water considerably reduces the efficiency and performance of heat transfer equipments. In industrial practices, scale deposition could be reduced through physical or chemical methods. However, in some cases chemical methods are unpractical due to cost and contamination issues, rendering the physical methods the only feasible options. The objective of this study was to evaluate the effectiveness of two physical treatments in reducing scale depositions. One is to decrease the surface energy of the heat exchanger wall through surface modification; the other one is to change the crystallography of the small solid particles formed in the solution by applying a magnetic field. For the first method, the scale deposition on PTFE surfaces, SAMs (self-assembly monolayers) surfaces, polished copper surfaces, and polished stainless steel surfaces are investigated respectively. Copper and stainless steel surfaces were modified by micro-scale (μm thickness) PTFE (Poly-Tetrofluorethylene) films and nano-scale (nm thickness) thiolate SAMs. The surface energy of PTFE films and SAMs layers based on copper and stainless steel were significantly reduced compared with the untreated metal surfaces. To study the magnetic treatment effect on the formation of the calcium carbonate scale, a magnetic field up to 0.6 T was implemented in a simulated recirculation cooling water system. A large number of experiments were performed to study the effects of fluid velocity, heat flux, and the bulk concentration of the solution on the fouling rate and induction period of calcium carbonate on various modified surfaces. The experiments showed that the formation rate of the calcium carbonate scale was decreased on modified surfaces and the induction period was prolonged with the decrease of the surface energy. The study also showed that the nucleation and nucleate growth of calcium carbonate particles were enhanced through magnetic water treatment. In addition, using a higher flow rate and/or filtration of suspended calcium carbonate particles achieves a longer induction period.
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