Academic literature on the topic 'Chromium carbon and manganese electrodes'

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Journal articles on the topic "Chromium carbon and manganese electrodes"

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Salimi, Abdollah, Bahareh Pourbahram, Samira Mansouri-Majd, and Rahman Hallaj. "Manganese oxide nanoflakes/multi-walled carbon nanotubes/chitosan nanocomposite modified glassy carbon electrode as a novel electrochemical sensor for chromium (III) detection." Electrochimica Acta 156 (February 2015): 207–15. http://dx.doi.org/10.1016/j.electacta.2014.12.146.

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Cekerevac, Milan, Ljiljana Nikolic-Bujanovic, Anja Jokic, and Milos Simicic. "Investigation of electrochemical synthesis of ferrate - Part II: Optimization of the process parameters of ferrate(VI) electrochemical synthesis." Chemical Industry 64, no. 2 (2010): 111–19. http://dx.doi.org/10.2298/hemind100114006c.

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In part I [1] of the investigation the behavior of iron and selected low carbon steels in concentrated (10M - 15 M) water solution of NaOH and KOH in wide range of electrode potentials, between hydrogen evolution reaction and oxygen evolution reaction, is investigated and discussed. On the base of experimental data obtained by LSV and galvanostatic pulse methods, it is concluded [1] that efficient synthesis of ferrate (VI) can be expected in the region of anodic potentials between + 0,55 V and + 0,75 V against Hg|HgO reference electrode. In this paper optimization of electrolysis parameters of the electrochemical synthesis of ferrate(VI) is elaborated. The most important parameters chosen for optimization process were: anode material, alkaline electrolyte concentration, regime of electrical potential control, current density and electrolyte temperature. The best current efficiency and yield of ferrate(VI) synthesis of the explored anode materials (electrical steel, low carbon cold rolled steel plate, and structural steel) is obtained when electrical steel with 3 wt% of silicon is applied. The worst current efficiency is obtained with anodes made of structural steel with higher concentration of manganese, chromium and nickel. The influence of alloying elements on the process of electrochemical synthesis of ferrate(VI) is discussed in terms of their influence on formation and stability of anodic passive layer and oxygen evolution reaction. The increase of electrolyte concentration from 10M to 15M NaOH and KOH provided the increase of current efficiency with maximum obtained for 14M NaOH. The yield of ferrate(VI) synthesis increases with temperature raise, having maximal value at about +50?C, and after that, at higher temperatures, instability of ferrate(VI) increases and the yield of synthesis lessens. Considering the influence of electrical regime control it is concluded that the biggest yield of ferrate(VI) can be expected with constant anodic potential of about +0,65 V against Hg|HgO reference electrode and with pulsating potential with ratio Emax : Emin = +0,8 V : +0,5 V against Hg|HgO electrode and pulse duration of tmax : tmin = 2s : 1s, figure 1. Circulation of electrolyte has shown relatively small, but positive, effect on the synthesis efficiency, particularly in cases when potassium hydroxide is present in the electrolyte.
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Allen, Geoffrey C., and Josephine A. Jutson. "Carbon deposition on iron–manganese–chromium spinels." J. Mater. Chem. 1, no. 1 (1991): 73–78. http://dx.doi.org/10.1039/jm9910100073.

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Szkodo, Marek, Bolesław G. Gireń, and Janusz Steller. "Cavitation resistance of new chromium–manganese and chromium–cobalt electrodes and their metallographic structures." Wear 233-235 (December 1999): 111–19. http://dx.doi.org/10.1016/s0043-1648(99)00203-3.

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Chang, Jeng-Kuei, Chung-Ta Lin, and Wen-Ta Tsai. "Manganese oxide/carbon composite electrodes for electrochemical capacitors." Electrochemistry Communications 6, no. 7 (July 2004): 666–71. http://dx.doi.org/10.1016/j.elecom.2004.04.020.

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Peng, Yiting, Zheng Chen, Jing Wen, Qiangfeng Xiao, Ding Weng, Shiyu He, Hongbin Geng, and Yunfeng Lu. "Hierarchical manganese oxide/carbon nanocomposites for supercapacitor electrodes." Nano Research 4, no. 2 (December 17, 2010): 216–25. http://dx.doi.org/10.1007/s12274-010-0072-y.

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Wang, Yaohui, Hao Liu, Xueliang Sun, and Igor Zhitomirsky. "Manganese dioxide–carbon nanotube nanocomposites for electrodes of electrochemical supercapacitors." Scripta Materialia 61, no. 11 (December 2009): 1079–82. http://dx.doi.org/10.1016/j.scriptamat.2009.08.040.

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Lee, Seung Woo, Junhyung Kim, Shuo Chen, Paula T. Hammond, and Yang Shao-Horn. "Carbon Nanotube/Manganese Oxide Ultrathin Film Electrodes for Electrochemical Capacitors." ACS Nano 4, no. 7 (June 16, 2010): 3889–96. http://dx.doi.org/10.1021/nn100681d.

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Lin, Chuen-Chang, and Chia-Cheng Yen. "Manganese oxide precipitated into activated carbon electrodes for electrochemical capacitors." Journal of Applied Electrochemistry 38, no. 12 (June 17, 2008): 1677–81. http://dx.doi.org/10.1007/s10800-008-9616-1.

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Zhou, Y. K., B. L. He, F. B. Zhang, and H. L. Li. "Hydrous manganese oxide/carbon nanotube composite electrodes for electrochemical capacitors." Journal of Solid State Electrochemistry 8, no. 7 (June 1, 2004): 482–87. http://dx.doi.org/10.1007/s10008-003-0468-7.

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Dissertations / Theses on the topic "Chromium carbon and manganese electrodes"

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Oliver, Gossett Dunn. "A tribological study of arced sugar cane mill roll shells in Jamaica." Thesis, Brunel University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275927.

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Qwesha, Sibusiso. "Electrodeposition of multi-valent metal oxides at 1-methyl-3-octylimidazolium bis(trifluoromethylsulfonyl) imide ionic liquid - carbon paste electrode." University of the Western Cape, 2012. http://hdl.handle.net/11394/4618.

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>Magister Scientiae - MSc
A study on carbon paste electrode (CPE) materials containing 1-methyl-3-octylimidazolium bis (trifluoromethylsulfonyl) imide [MOIM[Tƒ2N] – a hydrophobic room temperature ionic liquid (IL) - is reported. CPEs with (a) the IL as the only binder (ILCPE) and (b) 1:1 (v/v) IL: paraffin mixture as the binder (ILPCPE) were prepared, characterized, and applied to the electrodeposition of films of multivalent transition metal oxides (MV-TMO) from five precursor ions (Fe2+, Mn2+, Cu2+, Co2+, Ce4+) in aq. KCl. Cyclic voltammetry (CV) showed a potential window of +1.5 V to -1.8 V regardless of the electrode type, including the traditional paraffin CP electrode (PCPE). However, the IL increased the background current by 100-folds relative to paraffin. The electrochemical impedance spectroscopy (EIS) of ILPCPE in aq. KCl (0.1M) revealed two phase angle maxima in contrast with the single maxima for PCPE and ILCP. The study also included the CV and EIS investigation of the electrode kinetics of the Fe(CN)6 3-/4 redox system at these electrodes. The electrodeposition of Fe2+, Co2+, and Mn2+ possibly in the form of the MV-TMOs FexOy, CoxOy, and MnxOy, respectively, onto the electrodes was confirmed by the observation of new and stable cathodic and anodic peaks in a fresh precursor ion –free medium. CVs of H2O2 as a redox probe supported the same conclusions. Both ATR-FTIR spectra and SEM image of surface samples confirmed the formation of electrodeposited films. This study demonstrated that the use of this hydrophobic IL alone or in combination with paraffin as a binder gives viable alternative CPE materials with better performance for the electrodeposition of MV-TMOs films than the paraffin CPE. Thus, in combination with the easy preparation methods and physical “morpheability” in to any shape, these CPEs are potentially more useful in electrochemical technologies based on high surface-area MV-TMO films in general, and MnxOy films in particular.
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Klankowski, Steven Arnold. "Hybrid core-shell nanowire electrodes utilizing vertically aligned carbon nanofiber arrays for high-performance energy storage." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/27651.

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Doctor of Philosophy
Department of Chemistry
Jun Li
Nanostructured electrode materials for electrochemical energy storage systems have been shown to improve both rate performance and capacity retention, while allowing considerably longer cycling lifetime. The nano-architectures provide enhanced kinetics by means of larger surface area, higher porosity, better material interconnectivity, shorter diffusion lengths, and overall mechanical stability. Meanwhile, active materials that once were excluded from use due to bulk property issues are now being examined in new nanoarchitecture. Silicon was such a material, desired for its large lithium-ion storage capacity of 4,200 mAh g[superscript]-1 and low redox potential of 0.4 V vs. Li/Li[superscript]+; however, a ~300% volume expansion and increased resistivity upon lithiation limited its broader applications. In the first study, the silicon-coated vertically aligned carbon nanofiber (VACNF) array presents a unique core-shell nanowire (NW) architecture that demonstrates both good capacity and high rate performance. In follow-up, the Si-VACNFs NW electrode demonstrates enhanced power rate capabilities as it shows excellent storage capacity at high rates, attributed to the unique nanoneedle structure that high vacuum sputtering produces on the three-dimensional array. Following silicon’s success, titanium dioxide has been explored as an alternative highrate electrode material by utilizing the dual storage mechanisms of Li+ insertion and pseudocapacitance. The TiO[subscript]2-coated VACNFs shows improved electrochemical activity that delivers near theoretical capacity at larger currents due to shorter Li[superscript]+ diffusion lengths and highly effective electron transport. A unique cell is formed with the Si-coated and TiO[subscript]2-coated electrodes place counter to one another, creating the hybrid of lithium ion battery-pseudocapacitor that demonstrated both high power and high energy densities. The hybrid cell operates like a battery at lower current rates, achieving larger discharge capacity, while retaining one-third of that capacity as the current is raised by 100-fold. This showcases the VACNF arrays as a solid platform capable of assisting lithium active compounds to achieve high capacity at very high rates, comparable to modern supercapacitors. Lastly, manganese oxide is explored to demonstrate the high power rate performance that the VACNF array can provide by creating a supercapacitor that is highly effective in cycling at various high current rates, maintaining high-capacity and good cycling performance for thousands of cycles.
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Brunner, David R. "The Composition and Distribution of Coal-Ash Deposits Under Reducing and Oxidizing Conditions From a Suite of Eight Coals." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2642.

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Eighteen elements, including: carbon, oxygen, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium, calcium, titanium, chromium, manganese, iron, nickel, strontium, and barium were measured using a scanning electron microscope with energy dispersive spectroscopy from deposits. The deposits were collected by burning eight different coals in a 160 kWth, staged, down-fired, swirl-stabilized combustor. Both up-stream and down-stream deposits from an oxidizing region (equivalence ratio 0.86) and reducing region (equivalence ratio 1.15) were collected. Within the deposits, the particle size and morphology were studied. The average particle cross-sectional area from the up-stream deposits ranged from 10 - 75 µm2 and had a standard deviation of 36 - 340 µm2. These up-stream particles were of various shapes: spherical, previously molten particles; irregular particle that had not melted, hollowed spherical shells; and layered or strands of particles. These particles were a mixture of burned and unburned coal being deposited at various stages of burnout and having completed some burnout after deposition. The average particle cross-sectional area from the down-stream deposits ranged 0.9 - 7 µm2 and the standard deviation range of 2.6 - 30 µm2. The shape of the particles on the bottom sleeves are typically spherical indicating melting prior to deposition. Particles contained a distribution of elemental compositions that were not tightly grouped on ternary phase diagrams. This indicated that particles were not single compounds or phases but each particle contained a mixture of multiple compounds. Coals' deposit sulfur was strongly correlated with the calcium and iron content of the ASTM ash analysis. The low rank sub-bituminous and lignite coals that had high calcium content produced high sulfur deposits, particularly in the oxidizing region, down-stream deposits. The high iron bituminous coals, also produced high sulfur deposits, but more so in the reducing region, up-stream deposits. The low calcium and low iron coals produced low sulfur deposits. Mahoning was an exception being high in iron content but remaining low in sulfur content in the deposit. Gatling coal showed numerous deposit particles that contained only iron and sulfur consistent with the high pyrite content of Gatling coal. The average concentration of chlorine was insignificant in all of the deposits with the concentration being less than 100 ppm. Individual particles containing chlorine were found and were associated with potassium, sodium, and iron.
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Kuo, Chung-Lun, and 郭仲倫. "The effects of carbon nanotube modification and manganese oxide annealing on capacitive characteristics of manganese oxide / carbon nanotube composite electrodes." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/58540311873972928094.

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碩士
國立雲林科技大學
化學工程與材料工程系碩士班
100
In recent years with the 3C industry (computers, communications and consumer electronic products)''s flourish, industry for efficient can and high reliability level of the energy storage element needs also will increase, but the purpose of this thesis, the text of for the development of high power density level,electrochemical capacitors for high energy density and long life to take this future increase 3C products in performance, reliability, and cost competitive advantage; this study is to dip way through the thermal decomposition to graft manganese metal oxide nanothe carbon control preparation nanoscale electrochemical capacitor electrodes. The experiment will be to cobalt catalyst plating aluminum foil substrate using chemical vapor deposition method prepared carbon nanotubes, CNTs aluminum foil the pickling or atmospheric heat treatment modified immersion manganese nitrate solution, and then through thermal decomposition of manganese oxide, explore the different thermal decomposition temperature and of its drape manganese oxide capacitance value; CNTs manganese oxide composite electrode prepared in different conditions, cyclic voltammetry and the chronopotentiometry future investigate the capacitor, cycle life, trying to figure out the preparation of the best conditions. The best parts of the experiment: carbon nanotube aluminum foil electrode by 61wt.% HNO3 pickling 5min disseminated 50wt.% Mn(NO3)2 solution 5min, place a high temperature furnace to 300℃ heat treatment generated manganese oxide. The test via cyclic voltammetry, the potential range of 0-1 V, scan rate of 0.1 V/s, electrolyte 0.5M Na2SO4, measured the highest specific capacitance 494.65 mF/cm2
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Tseng, Li-Hsin, and 曾麗馨. "Syntheses of Manganese Dioxide/Activated Carbon/Graphene Composite Electrodes and Their Applications in Supercapacitors." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/qc3g3x.

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碩士
國立清華大學
材料科學工程學系
105
In this work, three dimensional graphene was synthesized by the chemical vapor deposition method using nickel foam as a template. Activated carbon was dip-coated with graphene to combine carbon materials of different dimensions. Subsequently, MnO2/activated carbon/graphene composite electrodes with hierarchical pore structure and controllable MnO2 loading were synthesized using a self-limiting growth method; this was achieved by redox reactions of KMnO4 on sacrificial carbon materials. Furthermore, the capacitances between the carbon-only electrodes and the MnO2/carbon composite electrodes were compared. The former one are normally electrochemical double-layer capacitors, nevertheless, the latter one also show pseudocapacitive properties. The optimum MnO2/activated carbon/graphene composite electrode exhibited a specific capacitance of 813.0 F/g at a current density of 1 A/g, as well as good stability of 98.4% capacitance retention after 1000 cycles. When the symmetric solid-state supercapacitor was built from MnO2/activated carbon/graphene composite electrodes, it showed an energy density of 33.9 Wh/kg and a power density of 319.3 W/kg. Results of the feasibility tests indicate that the composite electrodes can be promising for supercapacitor applications.
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Chang, Ya Jing, and 張雅菁. "Reactions of hexavalent chromium with black carbon when co-existing with iron or manganese hydrous oxides." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/11149999038953198983.

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碩士
國立中興大學
土壤環境科學系所
100
Cr(VI) is one of the pollutants of major concern in the environment due to its high toxicity and carcinogenicity. In oxic soils, organic matter (OM) and black carbon (BC) are the predominant reductants that can reduce toxic Cr(VI) to less toxic Cr(III). However, Cr(VI) still can be leached to deeper layers of soil or even into groundwater. The low reduction rate of Cr(VI) is presumably attributed to the reactions of other soil constituents with Cr(VI) that inhibit the reduction of Cr(VI) by OM and BC. Thus, in this study, the influences of hydrous oxides of Fe and Mn on the Cr(VI) reduction of BC were investigated. The results showed that the co-existence of goethite with BC inhibited the Cr(VI) reaction of BC due to the fast adsorption rate and strong desorption hysteresis of Cr(VI) on goethite. Nonetheless, the prolonged reaction of Cr(VI) with BC and goethite removed Cr(VI) from solution through the adsorption of Cr(VI) and the subsequent reduction of adsorbed Cr(VI) to Cr(III). The resulting Cr(III) is either released back into solution or bound on BC. When MnO2 coexisted with BC, the aqueous Cr(III) were oxidized to Cr(VI) by MnO2. The Cr(III) oxidation and releasing back into solution occur as coupled reactions. The oxidation of aqueous Cr(III) by MnO2 inhibited the Cr(VI) reduction by BC when MnO2 coexisted with BC. At lower pH, the net positive charge on the surface of BC resulted in electrostatic repulsion between Cr(III) and BC. On the other hand, the oxidation of Cr(III) by Mn oxide led to the formation of Cr(VI) in solution, which was subsequently reduced by BC and consequently enhanced the removal of total Cr by BC at lower pH when BC coexisted with MnO2. In summary, the presence of Fe and Mn oxides inhibited the reduction of Cr(VI) by BC, leading to an increasing risk of Cr(VI) contamination in soil. Thus, the interactions between different soil consitutents need to be considered in order to have better understanding of the environmental risks of Cr contamination in soil.
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Ho, Yu-Sheng, and 何育昇. "Synthesis of vertical alignment and higher density carbon nanotubes for manganese-cobalt-znic oxide/carbon nanotube complex electrodes of electrochemical capacitors." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/48133917945923255250.

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碩士
國立雲林科技大學
化學工程與材料工程研究所
100
Characteristics of electrochemical capacitors include higher energy density, higher power density, and longer life cycle. They can be applied in 3C (Computer, Communication, Consumptive electronic product) and the quality, reliability and cost competition advantage of 3C products can be improved. Thus, Ti will be sputtered on Si and then Co will be sputtered on Ti by radio frequency (RF) and directly subsequent CVD with different different NH3 flow rates as well as temperatures will be used to prepared carbon nanotubes. Next, carbon nanotubes will be annealed by nitrogen-plasma treatment. Finally, manganese-cobalt-zinc oxide will be sputtered on inner and outer walls of carbon nanotubes by radio frequency (RF). In addition, the electrodes will be tested by SEM, XPS, gas adsorption meter, and Raman, etc... Furthermore, in order to find better prepared methods and conditions of the electrodes, the cyclic voltammetry (CV) will be taken for the electrodes.
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Tsai, Jiun-Hsien, and 蔡君賢. "Preparation of the carbon paste electrodes modfied by chromium hexacyanoferrate(II) and its application to amperometric biosensors." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/82066403359479182102.

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碩士
南台科技大學
化學工程系
93
A study was conducted to use the Chromium Hexacyanoferrate(II) [KCrHCF(II)] to modify the carbon paste electrode (CPE). The responding current for detecting H2O2 or glucose at the reductive potential was measured to determine the concentrations H2O2 or glucose. The results showed that the carbon paste electrode modified by KCrHCF(II) possessed a good linearity for detection of H2O2 (the linear range was 0.0125 ~ 15 mM, R2 = 0.9997) and that the sensitivity for reduction of H2O2 was about 151.55 μA/cm2-mM H2O2. The sensitivity (2.01 mA/cm2-mM H2O2) for reduction of H2O2 for the CPE modified by the nanosized KCrHCF(II) could be elevated to about 13 times of that of CPE modified by the unnanosized KCrHCF(II). The linear range was 0.005 ~ 17 mM and the R2 was 0.9995 for reduction of H2O2 for the CPE modified by the nanosized KCrHCF(II). The results showed that the KCrHCF(II) could increase the ability of reduction of H2O2 and if the KCrHCF(II) was nanosized, it could increase the ability of reduction of H2O2 significantly and consequently increase the responding current. If the mixed method was used to immobilize the Glucose Oxidase onto the CPE modified by the KCrHCF(II), the linear range for the detection of glucose was about 0.05 ~ 1.95 mM (R2 = 0.9965) and the sensitivity was about 1.28 μA/cm2-mM C6H12O6. If the entrapping method was used to immobilize the Glucose Oxidase, the linear range for the detection of glucose could be elevated to about 0.025 ~ 1.625 mM (R2 = 0.9993), and also the sensitivity could be elevated to about 23.11 μA/cm2-mM C6H12O6. Furthermore, we had accomplished in the preparation of the amperometric sensing strips for the detection of glucose by using the entrapping method and the screen-printing technique. Through the detection of glucose by the screen-printed electrodes (SPEs), the sensitivity was about 24.76 μA/cm2-mM C6H12O6 and the linear range was about 0.025 ~ 1.875 mM (R2 = 0.9968). The results were not quite satisfactory but since the KCrHCF(II) possesses the pretty good characteristic of catalytic ability for reduction of H2O2. If the method of immobilization of enzyme can be further modified, the sensitivity and linear range for detection of glucose will be elevated and this will be the goal of our further study.
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Poland, Ross Rivers. "Advances in Synthesis of Co- and Ter- Polycarbonates and Polyesters from Non-Petroleum Feedstocks and Kinetic Studies of Ligand Substitution from Manganese Half-Sandwich Complexes." Thesis, 2012. http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-10906.

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This dissertation is written in two parts. The first pertains to polycarbonate and polyester synthesis using relatively benign processes. The synthesis of polycarbonates from the coupling of CO2 and epoxides catalyzed by transition metal catalysts has long been studied in the DJD group. The benefits of this process are that it utilizes comparatively benign reagents, can be performed using no extraneous solvent, and is 100% atom efficient. A method potentially useful for achieving more desirable polycarbonate properties is to produce an epoxide A/epoxide B/CO2 terpolymer, thus allowing more fine "tuning" of properties to what one may desire while simultaneously influencing relative epoxide reactivity to potentially increase catalytic turnovers. Specifically, the coupling of propylene oxide and cyclohexene oxide with CO2 to yield a random copolymer with tunable properties has been studied via a Fineman-Ross analysis. Propylene oxide was found to be incorporated into the resultant polymer chain with anywhere from 4-10 times the preference of cylcohexene oxide. Although it has been reported as early as 1969, the copolymerization of epoxides and cyclic anhydrides catalyzed by transition metal complexes to yield polyesters via a chain-growth mechanism has recently gained much attention. This robust method of polyester synthesis can utilize rather inexpensive reagents to synthesize an array of polyester products which have a wide range of Tg values (-30 degrees C ? 90 degreesC), achievable through simple monomer selection. The second part of this dissertation deals with the kinetic study of ligand substitution from manganese carbonyl metal fragments. Some time ago it was postulated that complexes of the (Cp)M(CO)2L variety undergo ligand substitution via a associative mechanism allowed by a haptotropic eta5-eta3 shift in the eta5 ligand. Through kinetic studies and theoretical modeling, an approximate activation energy barrier of ~34 kJ/mol has been calculated for the ring slip of (2,5-dimethylpyrrole)Mn to occur. Additionally, further kinetic studies were performed in which Tp, a ligand electronically similar to Cp, was compared to MnCp complexes.
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Book chapters on the topic "Chromium carbon and manganese electrodes"

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Wilson, P. R., Z. Chen, Chris R. Killmore, and Stuart J. Laird. "Selective Oxidation of Manganese and Chromium during Annealing of Low Carbon Strip Steels." In THERMEC 2006 Supplement, 762–67. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-429-4.762.

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Varnauskas, Valentinas, Algirdas Vaclovas Valiulis, and Vitalijus Rudzinskas. "Investigation of Alloy Elements Transfer in Arc Facing by High Carbon and Chromium Content Electrodes." In Solid State Phenomena, 257–60. Stafa: Trans Tech Publications Ltd., 2008. http://dx.doi.org/10.4028/3-908451-60-4.257.

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Massardier, Véronique, David Colas, and Jaques Merlin. "Role of Manganese and Chromium on the Segregation Kinetics of Carbon and Nitrogen to the Dislocations in Ferritic Steels." In THERMEC 2006, 4303–8. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-428-6.4303.

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"Internal Oxidation." In Carburizing, 11–36. ASM International, 1999. http://dx.doi.org/10.31399/asm.tb.cmp.t66770011.

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Abstract Gas carburizing is known to promote internal oxidation in steel which can adversely affect certain properties. This chapter discusses the root of the problem and its effect on component lifetime and performance. It explains that gas-carburizing atmospheres contain water vapor and carbon dioxide, providing oxygen that reacts with alloying elements, particularly manganese, chromium, and silicon. It examines the composition and distribution of oxides produced in different steels and assesses the resulting composition gradients. It describes how these changes influence the development of high-temperature transformation products as well as microstructure, hardenability, and carbon content and properties such as fatigue and fracture behaviors, hardness, and wear resistance. It also explains how to manage internal oxidation through material design, process control, and other measures.
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Conference papers on the topic "Chromium carbon and manganese electrodes"

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Eiholzer, Cheryl R. "Laser Cladding Of Chromium-Manganese-Carbon On Low Carbon Steel For Wear Resistance." In 1986 Quebec Symposium, edited by Walter W. Duley and Robert W. Weeks. SPIE, 1986. http://dx.doi.org/10.1117/12.938893.

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Cetin, Bora, Ahmet H. Aydilek, and Lin Li. "Manganese and Chromium Leaching from High Carbon Fly Ash Amended Embankments." In GeoCongress 2012. Reston, VA: American Society of Civil Engineers, 2012. http://dx.doi.org/10.1061/9780784412121.385.

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Li, Siwei, Xiaohong Wang, and Caiwei Shen. "High-energy-density on-chip supercapacitors using manganese dioxide-decorated direct-prototyped porous carbon electrodes." In 2014 IEEE 27th International Conference on Micro Electro Mechanical Systems (MEMS). IEEE, 2014. http://dx.doi.org/10.1109/memsys.2014.6765662.

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Surekha, B., Sudiptha Swain, Abu Jafar Suleman, and Suvan Dev Choudhury. "Performance capabilities of EDM of high carbon high chromium steel with copper and brass electrodes." In INTERNATIONAL CONFERENCE ON FUNCTIONAL MATERIALS, CHARACTERIZATION, SOLID STATE PHYSICS, POWER, THERMAL AND COMBUSTION ENERGY: FCSPTC-2017. Author(s), 2017. http://dx.doi.org/10.1063/1.4990223.

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Fiore, Susan R., and Matthew A. Boring. "Evaluation of Hydrogen Cracking in Weld Metal Deposited Using Cellulosic SMAW Electrodes." In 2006 International Pipeline Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/ipc2006-10392.

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In a previous study of the limitations of cellulosic coated electrodes, it was found that arc length has a pronounced effect on carbon, manganese, and silicon recovery in welds made using these electrodes. The effect of arc length could not explain the extremely rich compositions observed in a series of cracked girth welds that were analyzed, however. Subsequent investigation demonstrated that it was possible to effectively double the manganese concentration and triple the silicon concentration when using cellulosic-coated electrodes with low moisture contents in the coatings. A variety of multipass weld metal cracking tests were reviewed and a test method that can be performed as part of a procedure qualification/material qualification test to determine appropriate preheat/interpass temperatures was developed. This paper describes the results of a follow-on program funded by Pipeline Research Council International (PRCI) and the US Department of Transportation. The objectives of the program were to further define the conditions that can lead to hydrogen cracking in weld metal deposited using cellulosic coated electrodes, in terms of operator preference (arc length), electrode properties, power supply selection, and materials handling, and to develop welding and safe handling guidelines to prevent weld metal hydrogen cracking. Cellulosic coated electrodes were procured from several manufacturers. Initially, they were checked for weld metal chemical composition in the as-received and dried conditions. The coating moisture of each electrode in each condition was also determined. Some of the electrodes were selected for additional testing in the as-received, dried and re-hydrated conditions. Pipe sections were welded with each electrode in each condition, using both a short arc length and a medium arc length. Weld metal testing included tensile testing, bend testing and weld metal chemical analysis. In the second phase of this program, additional welds were made with two of the electrodes using different power sources. Electrodes were also exposed to conditions intended to simulate actual weather conditions from around the world, in an effort to produce guidelines for maximum exposure times at the various conditions.
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6

Rajan, Viadyanath, and Dennis Hartman. "Metal-Cored Welding GMAW Consumables Development for Girth Welding of X-100 Pipe." In 2006 International Pipeline Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/ipc2006-10358.

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Metal-cored wire electrodes with different compositions were used to make girth weld joints at a heat input of 0.7–0.8 kJ/mm. Design of experiments methodology was used to create a response surface primarily in carbon (C), manganese (Mn) and nickel (Ni) space in steel containing molybdenum (Mo), titanium (Ti), and boron (B) additions. This allowed the modeling of all-weld-metal yield strength, tensile strength and Charpy impact toughness as a function of weld metal composition. Results indicated that weld metal yield and tensile strengths have a linear dependence on the %C, %Mn and %Ni content of the weld. The Charpy impact toughness behavior at −20° C was more complex, initially showing a dependence on %C and %Ni in small scale trials, and subsequently showing a dependence on the %oxygen (O) and %Mn content in full scale production trials. These results can be combined for graphical optimization of the response surface to identify regions in weld metal composition that contain the desired weld metal yield, tensile and Charpy impact toughness for design of metal-cored wire electrodes for the welding of X-100 pipe. These results and their implications for design of girth welds in X-100 pipe are presented in this study.
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7

Collins, L. E., P. Wei, S. Nafisi, P. Wang, and J. B. Wiskel. "Effects of Segregation on the Mechanical Performance of X70 Line Pipe." In 2016 11th International Pipeline Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/ipc2016-64302.

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Elemental segregation during continuous casting of steel is an inherent part of the solidification process. After rolling, the segregation is evident through banding of the microstructure, particularly at the centerline where the enrichment of such elements as carbon, manganese, molybdenum and chromium, may locally increase the hardenability of the steel and result in the formation of harder microstructural features. While operational steps may be taken to minimize segregation during casting, complete elimination of segregation is almost impossible. Various slab rating systems have been defined over the years which are employed as a means to measure slab quality taking into account such factors as internal cracks and segregation. While these slab rating systems were intended to aid mill operators in assessing slab quality, in recent years slab ratings have been prescribed as a means of assessing pipe quality. In this study the properties of pipe produced from a slab with Mannesmann rating of 2 are compared to those of pipe produced from a slab with a rating of 3. The work has been supplemented by microprobe analyses to measure the degree of segregation. Increased levels of Mn and Si were found at the centerline of pipe processed from the Mannesmann 3 slab. In the final pipe, these centerline bands were 10 to 20 μm in thickness and exhibited increased hardness (HV 50g) in the Mannesmann 3 pipe as compared to the Mannesmann 2 pipe. Despite evidence of increased segregation, the mechanical properties (YS, UTS, Charpy, DWTT) of both pipes comfortably met X70 property requirements.
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8

Fiore, Susan. "New FCAW Electrode for Producing Ultra-Clean High-Toughness Welds in X-80 and X-100 Steel." In 2016 11th International Pipeline Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/ipc2016-64361.

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The challenges associated with the welding of high-strength pipeline steels, such as X-80 and X100, are well established. While there are many filler metals that provide either adequate strength or good impact toughness, it is difficult to find products that provide both. Add to that the need for all-position welding and high deposition rates, and the options become almost non-existent. Several years ago, Hobart® Filler Metals began working on a line of flux-cored arc welding (FCAW) consumables that are unique in the welding industry. The products have a basic slag system, but do not operate like traditional EXXXT-5 electrodes. Traditional T-5 electrodes have a low-melting, fluid slag, which makes welding out-of-position especially difficult. They also have a high level of calcium fluoride, which affects the stability of the arc and causes weld spatter. While the weld metal mechanical properties and crack-resistance are excellent, the welder appeal and ease-of-use tend to be sorely lacking in most EXXXT-5 electrodes. The new approach utilizes aluminum for deoxidation, which has the added benefit of very clean weld deposits. The composition has been carefully optimized with appropriate levels of carbon, silicon, nickel and manganese. Alternative fluorine sources are used in place of calcium fluoride, which results in very good welder appeal and all-positional capabilities, including vertical down. The novel use of aluminum in a gas shielded process results in very low oxygen, nitrogen and sulfur content, providing exceptionally clean, tough weld deposits. Although the new products have been produced over a range of strength levels, the primary emphasis of this paper is on E691T5-GC (E101T5-GC) and E831T5-GC (E121T5-GC) electrodes. Testing shows that tensile strength levels ranging from 700–880 MPa (100–128 ksi) can be achieved, with toughness levels of 120 J at −60°C (90 ft-lbs at −76°F) or better. The highly basic slag, combined with low weld metal hydrogen (less than 4 ml/100 gm), provides excellent resistance to cracking. The product can be used in all positions, including vertically down, making it an especially appealing choice for welding high-strength pipe.
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9

Pe´rez-Guerrero, Faustino, and Stephen Liu. "Explaining Porosity Formation in Underwater Wet Welds." In ASME 2007 26th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2007. http://dx.doi.org/10.1115/omae2007-29696.

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Macroscopic porosity in underwater wet welds is one of the main defects that deteriorate the mechanical properties of the wet welded joints. It is well established that weld metal porosity is a function of pressure, thus water depth. However, the mechanism of porosity formation is not well understood, therefore the problem is not yet mitigated to acceptable levels, particularly at water depths close to and beyond 100 m. To purposely produce porous welds similar to those obtained in wet welding, bead-on-plate (BOP) welds were deposited in air with gas metal arc welding (GMAW) with no shielding gas, with autogenous gas tungsten arc welding (GTAW) and GTAW with cold wire feed using insufficient shielding gas (8 CFH). During welding with both processes, oxygen from the atmosphere readily reacts with the alloying elements in the molten tip of the wire and in the weld pool. Under these conditions, droplets that detach from the wire electrode will generally contain a gas bubble, which is transported into the weld metal. These two welding processes were selected because there is no slag produced in the process. Slag slows down the cooling while giving enough time for degassing to occur, as in the case of shielded metal arc welding (SMAW) in air. Even with insufficient shielding gas, the autogenous GTAW welds did not exhibit porosity because there was no metal addition in the form of droplets. However, when a wire was fed into the arc, droplets detached from the wire in the oxidizing atmosphere transported gas into the weld pool, manifested as external and internal weld metal porosity. Similarly, the GMAW BOP welds exhibited internal porosity. When quenched in water, the droplets that detached from the electrode in these oxidizing conditions exhibited internal voids. Metal transfer analysis performed on the GMAW BOP welds associated short circuiting mode with large droplets and high porosity contents (10 pct.). Conversely, small droplets are expected to transport less gas and produce less porosity. Proof of concept welds using the pulsed current GMAW (GMAW-P) process resulted in higher droplet detachment frequency, smaller droplets and a low number of short circuiting droplets. Even though a few short circuiting events were still present, the GMAW-P process drastically reduced porosity to only 0.2 pct. Chemical reaction between oxygen and carbon generates CO gas at the bottom surface of the droplets in flat welding position, this gas ascends and is partially trapped inside the droplet. However, when the welding torch and base metal are rotated 90 degrees or in horizontal welding position, the CO gas generated escapes. Consequently there is no CO bubble in the pendant droplet or porosity in the weld metal. Wet welds were made with pulsed current using AWS E6010 electrode at a pressure equivalent to 50 m water depth. Porosity was reduced from 3.9 with constant current to 2.5 pct with pulsed current. Even when porosity was reduced with pulsed current, higher pulse frequency needs to be tested along with different peak and background current values to further reduce porosity. Flux covered electrodes with ferro-manganese, ferro-titanium and boron additions were extruded for wet welding. These electrodes produced wet welds with an average porosity of 1.2 pct., which could be further reduced to 0.85 pct. by better control of the arc at the beginning side of the weld.
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