Academic literature on the topic 'Oxygen conductor'
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Journal articles on the topic "Oxygen conductor"
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Dumélié, M., G. Nowogrocki, and J. C. Boivin. "Ionic conductor membrane for oxygen separation." Solid State Ionics 28-30 (September 1988): 524–28. http://dx.doi.org/10.1016/s0167-2738(88)80095-x.
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Zhu, Xuefeng, and Weishen Yang. "Composite membrane based on ionic conductor and mixed conductor for oxygen permeation." AIChE Journal 54, no. 3 (2008): 665–72. http://dx.doi.org/10.1002/aic.11410.
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Bastide, Béatrice, Sylvie Villain, Renée Enjalbert, and Jean Galy. "Oxygen diffusion pathway in the anionic conductor Bi26Mo9GeO68." Solid State Sciences 4, no. 5 (April 2002): 599–608. http://dx.doi.org/10.1016/s1293-2558(02)01303-1.
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Michel, C., L. Er-Rakho, and B. Raveau. "The oxygen defect perovskite BaLa4Cu5O13.4, a metallic conductor." Materials Research Bulletin 20, no. 6 (June 1985): 667–71. http://dx.doi.org/10.1016/0025-5408(85)90144-8.
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Bastide, Beatrice, Sylvie Villain, Renee Enjalbert, and Jean Galy. "Oxygen Diffusion Pathway in the Anionic Conductor Bi26Mo9GeO68." ChemInform 33, no. 35 (May 20, 2010): 12. http://dx.doi.org/10.1002/chin.200235012.
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Kramer, S. "A novel titanate-based oxygen ion conductor: Gd2Ti2O7." Solid State Ionics 82, no. 1-2 (November 15, 1995): 15–23. http://dx.doi.org/10.1016/0167-2738(95)00156-z.
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SCHOBER, T. "Transformation of an oxygen ion conductor to a proton conductor by solid state reaction." Solid State Ionics 176, no. 29-30 (September 2005): 2275–77. http://dx.doi.org/10.1016/j.ssi.2005.06.021.
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Paulus, Werner, Rajesh Dutta, Avishek Maity, Anna Marsicano, Monica Ceretti, and Alexei Bosak. "Sub-mesoscale oxygen ordering in non-stoichiometric oxygen ion conductor Pr2NiO4+δ." Acta Crystallographica Section A Foundations and Advances 75, a2 (August 18, 2019): e428-e428. http://dx.doi.org/10.1107/s2053273319091289.
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Martin, M. "Cation Demixing in an Oxygen Ion Conductor Exposed to an Oxygen Potential Gradient." ECS Proceedings Volumes 1999-19, no. 1 (January 1999): 308–16. http://dx.doi.org/10.1149/199919.0308pv.
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Matsushita, Y., A. Roushown, F. Izumi, H. Kitazawa, and M. Yashima. "Ionic path in oxygen-ionic conductor La9.70(Si5.8Mg0.2)O26.35." Acta Crystallographica Section A Foundations of Crystallography 63, a1 (August 22, 2007): s218. http://dx.doi.org/10.1107/s0108767307095025.
Full textDissertations / Theses on the topic "Oxygen conductor"
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Al-Musa, Abdullah Abdulaziz. "Partial oxidation of propene using solid electrolyte membrane reactors." Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/6915.
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This study investigates the efficiency of a calcia stabilised zirconia (CaSZ) solid electrolyte as an oxygen ion conductor. The study also examines the behaviour of the oxygen species conducted by the solid electrolyte compared to species provided in the gas phase for partial oxidation of hydrocarbons. In this work, an electrochemical cell of the form Air, AgHCaSZ//Ag, Carrier gas was used to investigate the electrochemical efficiency and stability of the solid electrolyte CaSZ conducting of oxygen ions under atmospheric pressure conditions at 500 degrees C by applying a range of electrical potentials from I to 16 volts across the electrochemical cell. Due to the applied potential oxygen anions are transferred across the solid electrolyte from the cathode side of the cell to the anode side. It was found that the employed electrolyte is approximately a 100% purely ionic conductor of oxygen ions in the range of electrical voltage applied from I to 10 volts. Above that range the cell started to degrade and loose its ionic efficiency. It was possible to generate gas mixtures containing trace quantities of oxygen. The viscosity of these gas mixtures as a function of oxygen concentration was determined using an established flow perturbation technique (Flux Response Technology). Partial oxidation of propene was used to investigate the difference between the oxygen species produced electrochemically via electrical potential application across the electrochemical cell Air, AgHCaSZ//Ag, Propene, Ar and oxygen provided in the gaseous state co-fed with propene over silver electrode under atmospheric pressure and 450 degrees C and 500 degrees C. It was found that the method of electrochemical provision of oxygen caused the silver catalyst to be more selective to 1,5-hexadeine, whereas the gaseous oxygen provision produced acrolein as the major product. Carbon dioxide formation was not affected by the method of oxygen provision. The Ag electrode was compared to an Au-rich Ag alloy electrode for propene partial oxidation using electrochemical provision. It was found that 1,5-hexadiene was the major product over both electrodes, but the Au-rich alloy was more selective for acrolein than the Ag electrode. This might be due to the gold serving as a separator between Ag particles which hinder the back-spill over of oxygen and allow desorption of molecular oxygen in the gas phase, which then re-adsorb molecularly on silver sites producing acrolein. The effect of the sequence of the method of oxygen provision on the partial oxidation of propene was tested using the electrochemical cell Y-BiMoHAg//CaSZ//Ag at 450 degrees C and atmospheric pressure. A sharp decrease in acrolein selectivity was found when oxygen was provided in the gas phase after treatment with electrochemical oxygen, while no significant effect was noticed when the electrochemical oxygen was used after treatment with gaseous oxygen. This large decrease in acrolein selectivity might be attributed to the severe reduction of the catalyst, which is probably caused by high electrical potential application. A temperature increase from 450 to 500 degrees C seemed to suppress the formation of acrolein for both methods of oxygen provision and enhance the 1,5-hexadiene formation.
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Zhang, Yaoqing. "Exploring novel functionalities in oxide ion conductors with excess oxygen." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2576.
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Functional materials, particularly metal oxides, have been the focus of much attention in solid state chemistry for many years and impact every aspect of modern life. The approach adopted in this thesis to access desirable functionality for enhanced fundamental understanding is via modifying existing materials by deploying reducing synthetic procedures. This work spans several groups of inorganic crystalline materials, but is unified by the development of new properties within host compounds of particular relevance to solid oxide fuel cell technology, which allow interstitial oxide ion conduction at elevated temperatures. The Ca₁₂Al₁₄O₃₂e₂ electride was successfully synthesized by replacing the mobile extra-framework oxygen ions with electrons acting as anions. The high concentration of electrons in the C12A7 electride gives rise to an exceptionally high electronic conductivity of up to 245 S cm⁻¹ at room temperature. Making use of the high density of electrons in Ca₁₂Al₁₄O₃₂e₂ electride, the strong N-N bonds in N₂ was found to be broken when heating Ca₁₂Al₁₄O₃₂e₂ in a N₂ atmosphere. A reaction between silicate apatites and the titanium metal yielded another completely new electride material La₉.₀Sr₁.₀(SiO₄)₆O₂.₄e₀.₂ which was found to be a semiconductor. To fully understand the role of oxygen interstitials in silicate apatites, high-resolution transmission electron microscopy (HRTEM) was employed as the main technique in probing how the oxygen nonstoichiometry is accommodated at the atomic level. Atomic-resolution imaging of interstitial oxygen in La₉.₀Sr₁.₀(SiO₄)₆O₂.₅ proved to be a success in this thesis. Substitution of oxygen in 2a and interstitial sites with fluoride ions in La[subscript(8+y)]Sr[subscript(2- z)](SiO₄)₆O[subscript(2+(3y-2z)/2)] (0
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Corallini, Serena. "Structure and dynamics of a new Brownmillerite compound Sr₂₋ₓBaₓScGaO₅ in view of possible application as oxygen ion electrolite at moderate temperature." Thesis, Rennes 1, 2013. http://www.theses.fr/2013REN1S172.
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Les conducteurs d'ions oxygène fonctionnant à des températures inférieures à 300 ° C sont des matériaux d'intérêt majeur pour une série d’applications technologiques telles que les piles à combustible solide, les batteries, les électrodes, les capteurs, des catalyseurs, etc. Cependant à l’heure actuelle, les conducteurs d'ions d'oxygène solides fonctionnent raisonnablement seulement à haute température, supérieure à 800°C, ce qui limite leur application. Dans la recherche de l'amélioration des conducteurs d'ions d'oxygène, la structure Brownmillérite (ABO2.5 éq. A2B2O5) a toujours joué un rôle important, en particulier dans le régime à basse température où la dynamique de la chaîne tétraédrique induit la mobilité de l'oxygène. Dans ce contexte, nous avons synthétisé une nouvelle phase Sr2-xBaxScGaO5 (avec x=0 SSGO et x= 0.1 SBSGO), contenant des ions 3d0 diamagnétiques et susceptible d’être un conducteur ionique pur. En fonction de la voie de synthèse, le composé présente deux polymorphes, orthorhombiques et cubiques, qui sont tous deux importants pour la conductivité de l'oxygène. La réaction à l’état solide conduit à une structure de type Brownmillerite orthorhombique tandis que la synthèse de fusion de zone (FTZ) donne une structure Pérovskite déficitaire en oxygène .Par diffraction neutronique sur poudre (D2B @ ILL) nous avons analysé la structure des deux polymorphes, en fonction de la température. Une analyse détaillée du type SSGO Brownmillerite montre que le Sc occupe les sites octaédriques, tandis que Ga occupe exclusivement les tétraèdres autres. Cet ordre de cations est assez inhabituel pour les structures de type Brownmillerite. La deuxième particularité est que Sr2-xBaxScGaO5 subit une transition de phase à partir d'une configuration ordonnée des chaines (GaO4), caractéristiques du groupe d’espace I2mb à température ambiante, vers une configuration désordonnée des chaînes dans le groupe d’espace Imma (à 500°C). Ce résultat important confirme notre hypothèse que le désordre est dynamique et il est la clé pour avoir un conducteur d'ions d'oxygène à températures modérées. La synthèse à des températures élevées (jusqu'à fusion), donne une structure cubique Pm ̅m, stable jusqu'à 1000 ° C. La structure est de type Pérovskite fortement déficitaire en oxygène. La mobilité de l’oxygène de ces nouveaux composés a été ensuite étudiée par la thermogravimétrie (TGA) couplée avec spectroscopie de masse (MS) après échange isotopique 18O-16O, par spectroscopie RAMAN et RMN couplée avec les calculs théoriques ab-initio (WIEN2k), par diffusion inélastique des neutrons (IN6@ILL) couplée avec des calculs de dynamiques moléculaire ab-initio (VASP). Les résultats obtenus via les études structurales et de dynamique de réseau montrent que l’activation de la mobilité ionique est liée à la transition vers la structure désordonnée Imma, qui implique une dynamique importante des chaines GaO4 et une diffusion unidimensionnel le long des canaux lacunaires. Ces résultats ont pu être reproduits par calculs de dynamique moléculaire, dans lesquels la diffusion ne concerne que les oxygènes des plans tétraédriques, et s’expliquent par des paramètres de maille a et c qui sont significativement augmentés par rapport à (Ca/Sr)FeO2.5Oxygen ion conductors operating at low temperature, below 300 ° C, are materials of major interest for several applications in the area of solid state ionicsas solid fuel cells, batteries, electrodes, sensors, catalysts, etc. However till now, the solid oxygen ion conductor works reasonably only at high temperatures above 800 ° C, which limits their application. In the search for improved oxygen ion conductors Brownmillerite structures ( ABO2.5 eq. A2B2O5 ) has always played an important role, especially in the low temperature regime where the dynamics of the tetrahedral chain induced mobility of oxygen. In this context, we have synthesized a new phase Sr1-xBaxScGaO5 with x = 0 (SSGO) and x = 0.1 (SBSGO) containing diamagnetic 3d0 ions to have a pure ion conductor. Depending on the synthesis route, the compound has two polymorphs, orthorhombic and cubic, which are both important for the oxygen conductivity. The reaction in the solid state leads to an orthorhombic Brownmillerite-type structure, while tmeling synthesis (using the Travelling Floating Zone method FTZ ) gives an oxygen-deficient Perovskite structure. The structures of both polymorphs were analyzed using the neutron powder diffraction as function of the temperature (D2B@ILL). A detailed analysis of SSGO Brownmillerite type shows that the Sc occupies octahedral sites, while the Ga occupies exclusively the tetrahedral ones. This cation ordering is unusual for the Brownmillerite structures. Moreover Sr2-xBaxScGaO5 undergoes a phase transition from an ordered configuration of the tetrahedral chains (GaO4) characteristic of I2mb space-group at room temperature, toward a disordered one characteristic of Imma space group (500 ° C). This important result confirms that the disorder of the tetrahedral chains is dynamic and it is the key to have oxygen ion conductor at moderate temperatures. Synthesis at elevated temperatures (up to melting point) gives a cubic structure Pm ̅m, stable up to 1000 ° C. The Perovskite -type structure is highly oxygen deficient. The mobility of the oxygen of these new compounds was studied by thermogravimetry analysis (TGA) coupled with mass spectrometry (MS) after the isotope exchange 18O-16O, by Raman and NMR spectroscopy coupled with theoretical ab-initio calculations (WIEN2k), by inelastic neutron scattering (IN6@ILL) coupled with calculations of ab-initio molecular dynamics (VASP ) . The results obtained from the structural and the lattice dynamics studies show that activation of the ion mobility is related to the transition to a disordered structure Imma, which implies an important dynamics of the chains GaO4 and the diffusion along the one-dimensional vacancy channel. These results have been reproduced by molecular dynamics calculations, in which the diffusion pathway is due only to the oxygen in the tetrahedral planes
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Guironnet, Laure. "Compréhension de l'influence des paramètres micro et nano structuraux sur les performances électrochimiques de conducteurs mixtes." Thesis, Limoges, 2017. http://www.theses.fr/2017LIMO0077.
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La technologie des membranes céramiques pour la production d’oxygène pur connaît un intérêt croissant pour remplacer le procédé de distillation cryogénique, très coûteux sur le plan énergétique. Cependant, à l’heure actuelle, les flux d’oxygène produits par la technologie membranaire ne sont pas suffisamment élevés pour être économiquement viable à l’échelle industrielle. Il est donc nécessaire d’améliorer les performances des membranes. Les résultats obtenus à travers ce travail de thèse, à l’aide d’un dispositif original, nous ont permis de mieux cerner les paramètres architecturaux permettant l’amélioration du flux de semi-perméation à l’oxygène en fonction des mécanismes limitant le transport de l’oxygène à travers la membrane. De ce fait, il est possible d’orienter les recherches vers des architectures plus complexes répondant au moins partiellement aux objectifs industrielsThe technology of ceramic membranes for oxygen separation knows a great interest due to high energetic efficiency in comparison with the cryogenic distillation process. However, for now, the oxygen fluxes produced by the membrane technology are not high enough for industrial applications. It is therefore necessary to improve the performances of the membranes. The results obtained in this work, using an original device, allowed us to a better understanding of the influence of architectural parameters on the oxygen flux and on the mechanisms limiting the transport of oxygen through the membrane. As a result, it is possible to investigate new architectures of membrane of which the oxygen flux could be close to industrial targets
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Akin, Figen Tulin. "Ionic Conducting Ceramic Membrane Reactor for Partial Oxidation of Light Hydrocarbons." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1021991903.
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Miyazaki, Kazunari. "Studies on proton-conducting ceramic fuel cells for hydrogen-carrier utilization." Kyoto University, 2020. http://hdl.handle.net/2433/254526.
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Alves, Fortunato Maíra. "La zircone yttriée : un nouveau support pour la catalyse environnementale." Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10175.
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L'objectif de ce travail est l'étude des interactions entre des nanoparticules de platine et la zircone yttriée (YSZ pour Yttria-Stabilized Zirconia), oxyde conducteur ionique. Il s'agissait de transposer les effets de promotion électrochimique de la catalyse mis en évidence sur des films polarisés de platine de faible dispersion déposés sur des membranes denses de YSZ à des systèmes catalytiques conventionnels à base de nanoparticules métalliques dispersées sur des poudres de YSZ. La migration des ions oxydes promoteurs n'est plus contrôlée par une polarisation électrique mais induite thermiquement. Ces travaux ont permis de mettre au point une méthode de mesure de la dispersion du Pt déposé sur la zircone yttriée. Les interactions Pt/YSZ et notamment celles entre les lacunes d'oxygène de YSZ et les nanoparticules de Pt ont été étudiées par réduction en température programmée et spectroscopie infrarouge. L'importance des lacunes d'oxygène du support YSZ sur les propriétés de chimisorption du Pt et sur son activité catalytique pour l'oxydation du propane a été clairement montrée. La migration thermique des ions oxydes a été étudiée par échange isotopique 18O/16O. Un mécanisme de la réaction de combustion du propane a été proposé incluant le rôle prépondérant des oxydes de réseau de YSZ contrairement aux supports conventionnels en silice et en zircone non substituée. Finalement, les paramètres pouvant influencer les interactions Pt/YSZ comme la surface spécifique de YSZ, le taux d'oxyde d'yttrium, la méthode de préparation de YSZ ainsi que la teneur et la taille des nanoparticules de Pt ont été évalués. Les résultats ont mis en évidence la migration thermique des ions oxydes du support vers le Pt dès 100 °C. D'autre part, l'échange entre les oxygènes du réseau et ceux de la phase gaz est extrêmement rapide dès 100°C. L'activité catalytique du Pt semble promue par la mobilité des oxygènes du supportThe aim of this work is to investigate the interactions between Pt nanoparticles and Yttria-Stabilized Zirconia (YSZ), an ionically conducting support. The idea was to overcome the effects of electrochemical promotion of catalysis (EPOC) observed on Pt/YSZ electrochemical catalysts which present low metal dispersion to conventional catalytic systems based on metallic nanoparticles finely dispersed on YSZ powered support. In that configuration, the migration of the oxygen ions from YSZ toward the Pt surface is not electrically controlled but thermally induced without any polarisation. First, we have established a new procedure to measure the Pt dispersion over YSZ. The metal support interactions between Pt and YSZ were characterized by Temperature Programmed Reduction and Infrared Spectroscopy. The importance of the YSZ oxygen vacancies on the chemisorptive behaviours of Pt as well as its catalytic for the propane oxidation was clearly demonstrated. The thermal migration of oxygen ions was validated by using the Isotopic Exchange procedure 18O/16O. The impact of these vacancies was evaluated and a mechanism of the propane deep oxidation on Pt/YSZ was proposed including the important role of bulk YSZ oxygen species in opposition with conventional supports such as silica and non-substituted zirconia. Finally, the key parameters that can influence the Pt/YSZ interactions such as the YSZ specific surface area, the yttria content, the YSZ preparation route as well as the loading and size of Pt nanoparticles were investigated. Our results point out that the thermal migration of oxygen ions from YSZ toward Pt surface occurs from 100 °C. In addition, the exchange between oxygen species from YSZ bulk and those from the gas phase is extremely fast starting from 100 °C. The Pt catalytic activity for the propane deep oxidation seems to be promoted by the mobility of the bulk YSZ oxygen species
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Bu, Junfu. "Advanced BaZrO3-BaCeO3 Based Proton Conductors Used for Intermediate Temperature Solid Oxide Fuel Cells (ITSOFCs)." Doctoral thesis, KTH, Tillämpad processmetallurgi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-165073.
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In this thesis, the focus is on studying BaZrO3-BaCeO3 based proton conductors due to that they represent very promising proton conductors to be used for Intermediate Temperature Solid Oxide Fuel Cells (ITSOFCs). Here, dense BaZr0.5Ce0.3Y0.2O3-δ (BZCY532) ceramics were selected as the major studied materials. These ceramics were prepared by different sintering methods and doping strategies. Based on achieved results, the thesis work can simply be divided into the following parts: 1) An improved synthesis method, which included a water-based milling procedure followed by a freeze-drying post-processing, was presented. A lowered calcination and sintering temperature for a Hf0.7Y0.3O2-δ (YSH) compound was achieved. The value of the relative density in this work was higher than previously reported data. It is also concluded that this improved method can be used for mass-production of ceramics. 2) As the solid-state reactive sintering (SSRS) represent a cost-effective sintering method, the sintering behaviors of proton conductors BaZrxCe0.8-xLn0.2O3-δ (x = 0.8, 0.5, 0.1; Ln = Y, Sm, Gd, Dy) during the SSRS process were investigated. According to the obtained results, it was found that the sintering temperature will decrease, when the Ce content increases from 0 (BZCLn802) to 0.3 (BZCLn532) and 0.7 (BZCLn172). Moreover, the radii of the dopant ions similar to the radii of Zr4+ or Ce4+ ions show a better sinterability. This means that it is possible to obtain dense ceramics at a lower temperature. Moreover, the conductivities of dense BZCLn532 ceramics were determined. The conductivity data indicate that dense BZCY532 ceramics are good candidates as either oxygen ion conductors or proton conductors used for ITSOFCs. 3) The effect of NiO on the sintering behaviors, morphologies and conductivities of BZCY532 based electrolytes were systematically investigated. According to the achieved results, it can be concluded that the dense BZCY532B ceramics (NiO was added during ball-milling before a powder mixture calcination) show an enhanced oxygen and proton conductivity. Also, that BZCY532A (NiO was added after a powder mixture calcination) and BZCY532N (No NiO was added in the whole preparation procedures) showed lower values. In addition, dense BZCY532B and BZCY532N ceramics showed only small electronic conductivities, when the testing temperature was lower than 800 ℃. However, the BZCY532A ceramics revealed an obvious electronic conduction, when they were tested in the range of 600 ℃ to 800 ℃. Therefore, it is preferable to add the NiO powder during the BZCY532 powder preparation, which can lower the sintering temperature and also increase the conductivity. 4) Dense BZCY532 ceramics were successfully prepared by using the Spark Plasma Sintering (SPS) method at a temperature of 1350 ℃ with a holding time of 5 min. It was found that a lower sintering temperature (< 1400 ℃) and a very fast cooling rate (> 200 ℃/min) are two key parameters to prepare dense BZCY532 ceramics. These results confirm that the SPS technique represents a feasible and cost-effective sintering method to prepare dense Ce-containing BaZrO3-BaCeO3 based proton conductors. 5) Finally, a preliminary study for preparation of Ce0.8Sm0.2O2-δ (SDC) and BZCY532 basedcomposite electrolytes was carried out. The novel SDC-BZCY532 based composite electrolytes were prepared by using the powder mixing and co-sintering method. The sintering behaviors, morphologies and ionic conductivities of the composite electrolytes were investigated. The obtained results show that the composite electrolyte with a composition of 60SDC-40BZCY532 has the highest conductivity. In contrast, the composite electrolyte with a composition of 40SDC-60BZCY532 shows the lowest conductivity. In summary, the results show that BaZrO3-BaCeO3 based proton-conducting ceramic materials represent very promising materials for future ITSOFCs electrolyte applications.QC 20150423
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Martin, Manfred. "Oxygen and cation diffusion processes in oxygen ion conductors." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-193656.
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We discuss oxygen and cation diffusion processes in oxygen ion conductors. While the high oxygen diffusivity determines the proper oxygen ion conductivity, slow cation diffusion processes are important for sintering and degradation processes. In the first part of the paper we discuss an analytical model for the ionic conductivity of a strongly acceptor doped, fluorite-type oxygen ion conductor, i.e. a concentrated solution of AO2 and BB2O3. The model can be applied, e.g., to yttria doped zirconia (YSZ) and gives a qualitative
explanation of the observed maximum of the conductivity as a function of the dopant fraction. The model considers nearest neighbor interactions between oxygen vacancies and dopant cations, which may be negligible, attractive or repulsive, and jump barriers that depend on the nature of the cation-cation edge that has to be crossed during a jump between adjacent oxygen sites. In the second part we discuss cation diffusion processes in doped lanthanum gallates (LSGM). The experimental results of nearly identical cation
diffusion coefficients in the A- and B-sublattices of the perovskite LSGM can be explained by a bound defect cluster mechanism containing cation vacancies of both the Aand the B- sublattice and anion vacancies.
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Martin, Manfred. "Oxygen and cation diffusion processes in oxygen ion conductors." Diffusion fundamentals 6 (2007) 39, S. 1-16, 2007. https://ul.qucosa.de/id/qucosa%3A14216.
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We discuss oxygen and cation diffusion processes in oxygen ion conductors. While the high oxygen diffusivity determines the proper oxygen ion conductivity, slow cation diffusion processes are important for sintering and degradation processes. In the first part of the paper we discuss an analytical model for the ionic conductivity of a strongly acceptor doped, fluorite-type oxygen ion conductor, i.e. a concentrated solution of AO2 and BB2O3. The model can be applied, e.g., to yttria doped zirconia (YSZ) and gives a qualitative
explanation of the observed maximum of the conductivity as a function of the dopant fraction. The model considers nearest neighbor interactions between oxygen vacancies and dopant cations, which may be negligible, attractive or repulsive, and jump barriers that depend on the nature of the cation-cation edge that has to be crossed during a jump between adjacent oxygen sites. In the second part we discuss cation diffusion processes in doped lanthanum gallates (LSGM). The experimental results of nearly identical cation
diffusion coefficients in the A- and B-sublattices of the perovskite LSGM can be explained by a bound defect cluster mechanism containing cation vacancies of both the Aand the B- sublattice and anion vacancies.
Books on the topic "Oxygen conductor"
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Tuller, Harry L., Johannes Schoonman, and Ilan Riess, eds. Oxygen Ion and Mixed Conductors and their Technological Applications. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-017-2521-7.
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Flynn, Joseph H. Thermal and material transport and the solubility of oxygen and other gases in oxidizing polymers. Gaithersburg, MD: National Bureau of Standards, Dept. of Commerce, 1987.
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Kronhausen, Eberhard. Formula for life: The anti-oxidant, free-radical, detoxification program. New York: Morrow, 1989.
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Kronhausen, Eberhard. Formula for life. New York: Quill, 1999.
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H, Steele B. C., and Institute of Materials, eds. Ceramic oxygen ion conductors and their technological applications. London: Institute of Materials, 1996.
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Steele, B. C. H. Matsci: Ceramic Oxygen Ion Conductors and Their Technological Applications. Taylor & Francis Group, 1996.
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Schoonman, Joop, H. L. Tuller, and Ilan Riess. Oxygen Ion and Mixed Conductors and their Technological Applications. Springer, 2011.
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(Editor), H. L. Tuller, Joop Schoonman (Editor), and Ilan Riess (Editor), eds. Oxygen Ion and Mixed Conductors and their Technological Applications (NATO Science Series E:). Springer, 2000.
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Experimental thermal conductivity, thermal diffusivity, and specific heat values for mixtures of nitrogen, oxygen, and argon. [Boulder, Colo.]: U.S. Dept. of Commerce, National Institute of Standards and Technology, 1991.
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Scuffing characteristics of high-load rolling/sliding contacts operating in liquid oxygen: Effects of materials and surface roughness : technical report for the research conducted under grant/contract no. NAG8-1134. [Washington, DC: National Aeronautics and Space Administration, 1996.
Find full textBook chapters on the topic "Oxygen conductor"
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Kriegel, Ralf, and Christian Kaps. "Determination of the Oxygen Ion Diffusion Coefficients in SrMnO3−y Mixed Conductor by the Reoxidation Kinetics." In Functional Materials, 206–11. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2006. http://dx.doi.org/10.1002/3527607420.ch35.
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Zhang, Heng, Xin Fa Dong, and Wei Ming Lin. "Preparation of SrFe0.6Cu0.3Ti0.1O3-δ Mixed Oxygen-Ionic and Electronic Conductor." In High-Performance Ceramics V, 259–62. Stafa: Trans Tech Publications Ltd., 2008. http://dx.doi.org/10.4028/0-87849-473-1.259.
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Naumovich, E., V. Kharton, and F. M. B. Marques. "Measurement of Oxygen Ionic Transport in Mixed Conductors." In Mixed Ionic Electronic Conducting Perovskites for Advanced Energy Systems, 185–98. Dordrecht: Springer Netherlands, 2004. http://dx.doi.org/10.1007/978-1-4020-2349-1_16.
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Biallas, M., I. Trajkovic, F. Scholkmann, C. Hagmann, and M. Wolf. "How to Conduct Studies with Neonates Combining Near-Infrared Imaging and Electroencephalography." In Oxygen Transport to Tissue XXXIII, 111–17. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4614-1566-4_17.
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Boukamp, B. A., I. C. Vinke, K. J. Vries, and A. J. Burggraaf. "Surface Oxygen Exchange Kinetics of Solid Oxide Ion Conductors." In Fast Ion Transport in Solids, 167–80. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1916-0_9.
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Riess, I. "Solid State Electrochemical Cells." In Oxygen Ion and Mixed Conductors and their Technological Applications, 1–20. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-017-2521-7_1.
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Steele, B. C. H. "Dense Ceramic Ion Conducting Membranes." In Oxygen Ion and Mixed Conductors and their Technological Applications, 323–45. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-017-2521-7_10.
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Bieberle, A., and L. J. Gauckler. "Thermal and Isothermal Expansion." In Oxygen Ion and Mixed Conductors and their Technological Applications, 347–58. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-017-2521-7_11.
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Kleinlogel, C., and L. J. Gauckler. "Temperature Limitations in the Processing Sequence of Solid Oxide Fuel Cells." In Oxygen Ion and Mixed Conductors and their Technological Applications, 359–74. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-017-2521-7_12.
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Bieberle, A., and L. J. Gauckler. "Metallic Interconnector." In Oxygen Ion and Mixed Conductors and their Technological Applications, 375–87. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-017-2521-7_13.
Full textConference papers on the topic "Oxygen conductor"
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Idrus, L. H., A. K. Yahya, Swee-Ping Chia, Kurunathan Ratnavelu, and Muhamad Rasat Muhamad. "Resistance-Based Ceramic Ho123 Ionic Conductor for Oxygen Gas Sensing." In FRONTIERS IN PHYSICS: 3rd International Meeting. AIP, 2009. http://dx.doi.org/10.1063/1.3192242.
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Baek, Seung-Wook, Joongmyeon Bae, and Jung Hyun Kim. "Oxygen Reduction Mechanism at Sm0.5Sr0.5CoO3−δ/Sm0.2Ce0.8O1.9 Composite Cathode for Solid Oxide Fuel Cell." In ASME 2008 6th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2008. http://dx.doi.org/10.1115/fuelcell2008-65059.
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The oxygen reduction mechanism at porous Sm0.5Sr0.5CoO3−δ/Sm0.2Ce0.8O1.9 composite cathode, in which Sm0.5Sr0.5CoO3−δ is a perovskite type mixed ionic and electronic conductor (MIEC), was studied with respect to the oxygen partial pressure and temperature. Symmetric half cells with Sm0.2Ce0.8O1.9 electrolyte were prepared, and cathode behavior was measured by using electrochemical impedance spectroscopy at frequency range of 0.1Hz∼5MHz and temperature range of 400∼900°C. Oxygen partial pressure range for the measurement was from 0.0002 to 1atm. In present research, reaction model based on the empirical equivalent circuit was established. Three elementary reaction steps were considered to describe the oxygen reduction reaction at Sm0.5Sr0.5CoO3−δ/Sm0.2Ce0.8O1.9 composite cathode. Electrode resistances corresponding to the high and low frequency seem to represent the oxygen ion transfer at the interface of electrolyte and gas phase diffusion of oxygen, respectively, from electrochemical impedance analyses as functions of oxygen partial pressure and temperature. The medium frequency process is expected to correspond to the oxygen ion conduction in the bulk cathode from this study.
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Svoboda, Robert, Claudio Picech, and Herbert Hehs. "Experiences With Stainless Steel Hollow Conductors for Generator Stator Water Cooling." In ASME 2004 Power Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/power2004-52155.
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Copper is a traditional material for hollow conductors used in generator stator water cooling. However, stainless steel is a promising and proven alternative for use as hollow conductor material. In 30 years of industry experience, no failures were encountered related to cooling water chemistry with this material. This paper describes the history, electrical and mechanical considerations, water chemistry and materials behavior, and experience with stainless steel hollow conductors. Recommendations are provided on use of high purity water with no restriction on oxygen content.
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Bonneau, M., F. Gitzhofer, and M. Boulos. "SOFC/CeO2 Doped Electrolyte Deposition Using Suspension Plasma Spraying." In ITSC 2000, edited by Christopher C. Berndt. ASM International, 2000. http://dx.doi.org/10.31399/asm.cp.itsc2000p0929.
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Abstract Ceria (CeO2) based electrolytes have been considered for use in solid oxide fuel cells (SOFC) for more than 20 years. There are however some limitations to this usage that this study has tried to address, indeed the study objective has been that of synthesizing and thermal spraying thin layers (50 - 100 µm) of doped CeO2 by the technique of suspension plasma spraying, using radio frequency (RF) plasma technology. Various dopant combinations and concentrations have been selected for this work in order to increase the useful partial oxygen pressure range for satisfactory ionic conductivity development, thereby increasing the anionic conductivity and preventing CeO2 reduction in fuel cell service. Ceria possesses the fluorite crystal structure at low temperatures but does not have enough oxygen vacancies to be a good ionic conductor. In ceria the cerium have 4+ oxidation state within the fluorite structure, and by substituting a certain amount of Ce4+ ions by trivalent dopant ions, oxygen vacancies are induced into the structure. Recent studies have demonstrated that at low temperatures doped ceria seems to be a better electrolyte than doped zirconia. Also, it seems that dopants with ionic radii close to Ce4+ ions give rise to better ionic conductivities. The doped ceria conductivity increases with the dopant concentration because more oxygen vacancies are created, but at higher concentrations vacancy ordering occurs which results in decreased ionic conductivity.
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Saji, Genn. "A Review of Root Causes of SCC Phenomena in BWR/RBMK: Issues, Approaches, and Proposals." In 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49432.
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The author looked for potential mechanisms deemed insignificant in the early stages of SCC research and the current approach used in SCC studies were selected. The basis for those mechanisms was in non-nuclear corrosive environments as well as analyses of redox potential data measured under radiation. Three possible mechanisms were identified; ‘long cell action (which suppresses local cell cathodic activities and accelerates remote local cell anodic activities),’ ‘autocatalytic growth of cracks in crevice water chemistry,’ and ‘transpassive corrosion of stainless steel.’ The ‘long cell action’ has been identified as a key mechanism of soil corrosion which is induced by a difference in the availability of oxygen inside the soil. In this mechanism, conduction of electrons through an electric conductor over a long distance plays a significant role. This author proposes a hypothetical mechanism that states; ‘radiation-induced ‘long cell action’ causing electrolytic corrosion.’
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Kondo, Masatoshi, Minoru Takahashi, Susumu Yoshida, Naoki Sawada, Akira Yamada, and Koji Hata. "Experimental Studies on Pb-Bi Flow Technology and Steel Compatibility With Pb-Bi." In 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49285.
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For the development of the Pb-Bi cooled FBR and the ADS with Pb-Bi target, the compatibility of steels for core, structural and window materials with high temperature Pb-Bi is one of the critical issues. The effect of corrosion on the mechanical strength of steels should be also concerned. An oxide layer which is formed and self-healed on the steel surface in Pb-Bi is expected to improve the compatibility if oxide potential in Pb-Bi is controlled and monitored adequately to form stable oxide layer. Therefore, monitoring technology of oxygen concentration in Pb-Bi is required. In the present study, a performance test of oxygen sensor, a steel corrosion test and a steel mechanical strength test, or a pipe rupture test, were performed as follows: (1) Test of oxygen sensor: For the monitor of the oxygen potential in Pb-Bi, a thermal stress proof type oxygen sensor made of electrolyte conductor (MgO-ZrO2 and Y2O3-ZrO2) with the reference fluid of oxygen saturated bismuth was developed, and the performance test was conducted using the corrosion test loop. The performance was stable and reliable in the 1000-hour operation. The electromotive forces (EMF) of the sensor cells of MgO-ZrO2 and Y2O3-ZrO2 were nearly the same as each other, and they were not destructed during the 1000-operation. (2) Steel corrosion test: High Cr steels including heat resisting steels were exposed to a liquid Pb-Bi flow at the temperature of 550°C, the velocity of 1m/s, the oxygen concentration of 1.7×10−8wt% and the temperature difference of 150°C for 1000 and 500 hours. It was found that weight losses were lower in general in the steels with higher Cr content. The steels with high Cr, Si and Al formed thin oxide layers and exhibited better compatibility with Pb-Bi. (3) Steel mechanical strength test (pipe rupture test): Metallurgical analysis for ruptured pipe made of SS-316 was performed. The pipe had experienced the exposure to Pb-Bi at 400°C for 3440 hours, at 350°C for 4 hours, at 300°C for 50 hours, and at 250°C for 622 hours. Pipe rupture occurred possibly due to thermal expansion of Pb-Bi at heat-up processes. The results of the analysis indicated that Pb-Bi penetration to steel matrix occurred more seriously near the ruptured part than the other part of the pipe. The analytical result suggested that a brittle fracture might occur in the inner part of the ruptured pipe wall by liquid metal embrittlement because of Pb-Bi penetration, whereas dimples observed suggested that ductile fracture might occur in the outer part of the ruptured pipe wall.
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Saji, Genn. "A Review of Root Causes of SCC Phenomena in BWR/RBMK: An Overview of Radiation-Induced Long Cell Action Relevant to SCC." In 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49433.
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In a review of recent occurrences of Stress Corrosion Cracking (SCC) in Japanese Boiling Water Reactors (BWRs) and Russian High Power Channel-type Reactors (RBMKs), the author proposes a hypothetical mechanism which states; ‘radiation-induced ‘long cell action’ causing electrolytic corrosion.’ This article provides the currently available technical bases for the proposed mechanism which was introduced in a companion paper also presented at this conference [1]. There is some experimental evidence indicating that long cell action may not be negligible in nuclear reactor environments, when induced by the radiolysis of water. There are also some surprising similarities between SCC in the reactor systems and the basic mechanism of underground corrosion by long cell action. In this mechanism, the ‘long cell action’ is induced by a difference in availability of oxygen inside the soil. Conduction of electrons through an electric conductor over a long distance plays a significant role as they are released by dissolution of metallic ions and sucked up from the metal surface.
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Lee, R. A., and T. R. Lundquist. "Low Resistivity FIB Depositions Within High Aspect Ratio Holes." In ISTFA 1996. ASM International, 1996. http://dx.doi.org/10.31399/asm.cp.istfa1996p0085.
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Abstract The latest IC modification requirement is to decrease the resistivity of Focused Ion Beam (FIB) deposits, especially deposits within a FIB machined hole. The resistivity of platinum conductor deposited by FIB within a hole is much greater (5000-50000 (μΩ-cm) than that deposited on a surface (~200 |μΩ-cm) (1). Auger analysis of surface deposited platinum conductor gives the composition ratios as ~ 50% platinum, ~34% carbon, ~15% gallium and ~1 % Oxygen. The escape solid angle of the organic carrier is much less from a hole than from a surface; therefore, we find more of the non-conductive organic material is trapped inside the hole which increases the fill resistivity. With its planarization and multiple metal levels, advanced IC process technology forces contact to lower level metal to be through high aspect ratio holes. To make a low resistance contact through such a hole, deposited material must have a high ratio of platinum to carbon and Oxygen. An improved technique is needed to remove the organic carrier molecules and deposit material containing this higher platinum percentage. The way to achieve such deposition is to adjust gas arrival rate and beam current to produce a deposition rate that allows sufficient time for the organic carrier molecules to escape. Using this method, we can to obtain fill resistivity of about 1000-2500 (μΩ-cm within high aspect ratio holes. This paper discusses in detail the technique to achieve such low resistivity in high aspect ratio holes. On the surface where space is not so limited, a greater deposition rate yields shorter times to resistance as well as better step coverage, but within a hole a lower resistivity material is needed to result in good conductance to lower level metal.
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Brousse, E., G. Montavon, A. Denoirjean, P. Fauchais, and K. Wittmann-Teneze. "Gastight Yttria-Partially Stabilized Zirconia Layers Manufactured by Suspension Plasma Spraying for SOFC Electrolyte Functional Layers." In ITSC2009, edited by B. R. Marple, M. M. Hyland, Y. C. Lau, C. J. Li, R. S. Lima, and G. Montavon. ASM International, 2009. http://dx.doi.org/10.31399/asm.cp.itsc2009p0120.
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Abstract Intermediate temperature solid oxide fuel cells include in their design a solid electrolyte layer, usually made of yttria-stabilized zirconia, that acts as an ionic conductor through which oxygen ions diffuse. This layer must be as thin as possible to limit ohmic losses yet have a low leakage rate corresponding to a low level of connected stacking defects such as microcracks. Suspension plasma spraying (SPS) appears to be a viable method for manufacturing such layers and is used in this study to produce gastight coatings that with further improvements may meet the requirements of SOFCs. The paper describes the setup and optimization of the SPS process and the methods used to evaluate the solid electrolyte layers.
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Svoboda, Matthias, and Robert Svoboda. "Operation and Maintenance Solutions for Generator Water Cooling." In 2012 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icone20-power2012-54555.
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Plugging of copper hollow conductors in water cooled generators is an issue occasionally encountered in large nuclear, fossil and hydro powered power plants, causing load limitations or even unplanned shut-down. A response is the proper choice of stator water chemistry and of the purification systems. The common water chemistry regimes are with low or high oxygen content, and neutral or alkaline pH in the stator water. All these regimes have proven to work in the field, but none is without problems. This can be due to various causes. There is one common trait however: problems arise when the system is being exposed for any length of time to a regime it was not designed for. Stainless steel hollow conductors have only simple requirements on water chemistry. Hollow conductor plugging can lead to overheating and possibly to catastrophic failure, so swift action to remedy the situation is recommended. There are several options. Hot reverse flush can remove debris and temporarily open up the plugs, and mechanical cleaning can open totally blocked hollow conductors. There are several methods for chemical cleaning, the most common being different forms of acid cleaning and EDTA cleaning. The former has the disadvantage of dissolving base metal and brazing as well as the oxides, while the latter method manipulates less aggressive substances that only dissolve the copper oxides in the system.
Reports on the topic "Oxygen conductor"
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Virkar, Anil. Thermodynamic, Kinetic and Electrochemical Studies on Mixed Proton, Oxygen Ion and Electron (Hole) Conductors. Office of Scientific and Technical Information (OSTI), April 2022. http://dx.doi.org/10.2172/1864586.
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McKinnon, Mark, Craig Weinschenk, and Daniel Madrzykowski. Modeling Gas Burner Fires in Ranch and Colonial Style Structures. UL Firefighter Safety Research Institute, June 2020. http://dx.doi.org/10.54206/102376/mwje4818.
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The test scenarios ranged from fires in the structures with no exterior ventilation to room fires with flow paths that connected the fires with remote intake and exhaust vents. In the ranch, two replicate fires were conducted for each room of origin and each ventilation condition. Rooms of fire origin included the living room, bedroom, and kitchen. In the colonial, the focus was on varying the flow paths to examine the change in fire behavior and the resulting damage. No replicates were conducted in the colonial. After each fire scene was documented, the interior finish and furnishings were replaced in affected areas of the structure. Instrumentation was installed to measure gas temperature, gas pressure, and gas movement within the structures. In addition, oxygen sensors were installed to determine when a sufficient level of oxygen was available for flaming combustion. Standard video and firefighting IR cameras were also installed inside of the structures to capture information about the fire dynamics of the experiments. Video cameras were also positioned outside of the structures to monitor the flow of smoke, flames, and air at the exterior vents. Each of the fires were started from a small flaming source. The fires were allowed to develop until they self-extinguished due to a lack of oxygen or until the fire had transitioned through flashover. The times that fires burned post-flashover varied based on the damage occurring within the structure. The goal was have patterns remaining on the ceiling, walls, and floors post-test. In total, thirteen experiments were conducted in the ranch structure and eight experiments were conducted in the colonial structure. All experiments were conducted at UL's Large Fire Laboratory in Northbrook, IL. Increasing the ventilation available to the fire, in both the ranch and the colonial, resulted in additional burn time, additional fire growth, and a larger area of fire damage within the structures. These changes are consistent with fire dynamics based assessments and were repeatable. Fire patterns within the room of origin led to the area of origin when the ventilation of the structure was considered. Fire patterns generated pre-flashover, persisted post-flashover if the ventilation points were remote from the area of origin.
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Starkey, Eric, Daniel McCay, Chrisopher Cooper, and Mark Hynds. Assessment of estuarine water and sediment quality at Cape Hatteras National Seashore and Cape Lookout National Seashore: 2021 data summary. National Park Service, October 2022. http://dx.doi.org/10.36967/2294854.
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In July 2021 the Southeast Coast Network conducted an assessment of water quality in the vicinity of Cape Hatteras and Cape Lookout National Seashores as part of the National Park Service Vital Signs Monitoring Program. Monitoring was conducted following methods developed by the Environmental Protection Agency (EPA) as part of the National Coastal Assessment Program (EPA 2010). Laboratory analysis measured chlorophyll a and total and dissolved concentrations of nitrogen and phosphorous. Field measurements included water temperature, pH, dissolved oxygen, and salinity. Water clarity, which requires a Secchi depth measurement, was obtained when possible. All measured parameters were rated as good, fair, or poor based on thresholds set by the EPA (2012). All measured parameters were rated as good, fair, or poor based on thresholds set by the EPA (2012). Water clarity was not calculated at all sites due to the shallow depth of the water in the sound. Of the sites where water clarity could be assessed (5 sites), four measured good and one fair. Sites that were too shallow to measure water clarity had water column conditions that did not preclude light from penetrating to the bottom of the water body so no ecological effects would be expected.Turbidity measurements ranged from 1.0 to 8.0 FNU (Formazin Nephelometric Units) and are good (i.e. < 25 NTU [Nephelometric Turbidity Units]) according to North Carolina Standards (NC Administrative Code 2019). Note that turbidity units of FNU and NTU are roughly equivalent. Chlorophyll a concentration was rated good at 29 sites (97%), and fair at one site (3%). Dissolved inorganic nitrogen (DIN) concentration was good at all 30 sites (100%). Dissolved inorganic phosphorus (DIP) concentration was good at all 30 sites (100%). Dissolved oxygen concentration (bottom) was rated good at all 30 sites (100%). A water-quality condition summary index was calculated for each site sampled at Cape Hatteras and Cape Lookout National Seashores based on the categorical assessments of chlorophyll a, DIN and DIP concentrations, dissolved oxygen, and water clarity. This summary index indicated good water-quality conditions at all thirty sites (100%). Based on the summary water-quality index rating, overall water-quality conditions at Cape Hatteras and Cape Lookout National Seashores during sampling in 2021 were good. For sediment, ecological condition was ranked as good at 30 sites (100%). As a result, no adverse impacts to benthic organisms due to sediment contamination are anticipated at any of the sampled sites. This ranking was assigned according to the 2010 Environmental Protection Agency, National Coastal Condition Assessment (NCCA) thresholds for sediment chemistry.
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Sommer, Stefan, Sascha Flögel, Michael Walter, and Frank Wenzhöfer. Autonomous Robotic Network to Resolve Coastal Oxygen Dynamics : Cruise No. AL547, 20.10. – 31.10.2020, Kiel – Kiel, ARCODYN. GEOMAR Helmholtz Centre for Ocean Research Kiel, 2022. http://dx.doi.org/10.3289/cr_al547.
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The ALKOR cruise AL547 represents a concluding milestone of the Helmholtz innovation project ARCHES (Autonomous Robotic Networks to Help Modern Societies). The aim was to implement a heterogeneous robotic sensing network to simultaneously monitor changes in the water column and at the seafloor. The network has been developed by a consortium of partners from AWI, DLR, GEOMAR and the University of Kiel. The participating sensing platforms allow for real-time data transfer and the entire network shall be able to autonomously respond to environmental changes in the ocean. The network comprised seven different mobile and stationary platforms. Tests were conducted at the Mittelgrund working area in the entrance of the Eckernförde Bay (western Baltic Sea). During 47 stations the various sensing platforms were deployed and recovered for maintenance. A total of 87853 messages were sent using hydro-acoustics, of which 71734 messages contained O 2 data, 15177 were status messages, 926 messages were commands to trigger a change of the measurement behavior of a platform and 16 messages represented broadcasts about the environmental status. We synoptically recorded short-term O 2 time series on the different platforms, which were placed along a depth gradient in the working area. As the Eckernförde Bay is known for sporadic fish kills by anoxia we hope to contribute to a better understanding of the O 2 dynamics in coastal areas. - (ALKOR-Berichte ; AL547)
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Patil, Bhimanagouda S., Ron Porat, G. K. Jayaprakasha, and K. N. C. Murthy. Optimization of Postharvest Storage Conditions to Maintain Fruit Quality and Health Maintaining Properties of Grapefruit. United States Department of Agriculture, January 2010. http://dx.doi.org/10.32747/2010.7613879.bard.
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Antioxidant activity of fruits is gaining wide interest among consumers due to its importance in counteracting oxidative stress, free radicals and preventing DNA damage. Oxygen radical absorbance capacity (ORAC) assay is one of the commonly used assays to measure the antioxidant activity, which is based on hydrogen atom transfer mechanism. Furocoumarins present in grapefruit are reported to have antiproliferative activity, induce GST activity, inhibit biofilm formation and increase bioavailability of drugs. In the present project ORAC values were measured of Star Ruby grapefruit undergone ethylene degreening treatment, cold storage and temperature conditioning treatment, and modified atmosphere packaging which were stored at different temperatures for prolonged period. In addition, furocoumarins were quantified in Star Ruby grapefruits from cold storage and conditioning experiment conducted in Israel. Conditioning treatment is practiced prior cold storage to reduce chilling injury in grapefruits during cold storage for prolonged period. Levels of 6,7-dihyrdoxy bergamottin decreased during storage period in all three treatments.
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Cahaner, Avigdor, Sacit F. Bilgili, Orna Halevy, Roger J. Lien, and Kellye S. Joiner. effects of enhanced hypertrophy, reduced oxygen supply and heat load on breast meat yield and quality in broilers. United States Department of Agriculture, November 2014. http://dx.doi.org/10.32747/2014.7699855.bard.
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Original objectivesThe objectives of this project were to evaluate the growth performance, meat yield and quality attributes of broiler strains widely differing in their genetic potential under normal temperature vs. warm temperature (short and long-term) conditions. Strain differences in breast muscle accretion rate, metabolic responses under heat load and, gross and histopathological changes in breast muscle under thermal load was also to be characterized. BackgroundTremendous genetic progress has been made in broiler chicken growth rate and meat yield since the 1950s. Higher growth rate is driven by higher rates of feed intake and metabolism, resulting in elevated internal heat production. Hot rearing conditions negatively affect broiler growth by hindering dissipation of heat and may lead to a lethal elevation in body temperature. To avoid heat-induced mortality, broilers reduce feed intake, leading to depressed growth rate, lower weight gain, reduce breast meat yield and quality. Thus, the genetic potential of contemporary commercial broilers (CCB) is not fully expressed under hot conditions. Major conclusions, solutions, and achievementsResearch conducted in Israel focused on three broiler strains – CCB, Featherless, Feathered sibs (i.e., sharing similar genetic background). Complimentary research trials conducted at Auburn utilized CCB (Cobb 500, Cobb 700, Ross 308, Ross 708), contrasting their performance to slow growing strains. Warm rearing conditions consistently reduced feed intake, growth rate, feed efficiency, body weight uniformity and breast muscle yield, especially pronounced with CCB and magnified with age. Breast meat quality was also negatively affected, as measured by higher drip loss and paler meat color. Exposure to continuous or short-term heat stress induced respiratory alkalosis. Breast muscle histomorphometrics confirmed enhanced myofiber hypertrophy in CCB. Featherless broilers exhibited a significant increase in blood-vessel density under warm conditions. Rapid growth and muscle accretion rate was correlated to various myopathies (white striping, woody and necrotic) as well as to increases in plasma creatinekinase levels. Whether the trigger(s) of muscle damage is loss of cellular membrane integrity due to oxidative damage or tissue lactate accumulation, or to loss of inter-compartmental cation homeostasis is yet to be determined. Based on genome-wide single-nucleotide polymorphism array genotyping, identification of the gene with the recessive mutation Scaleless (sc) facilitated the development a dCAPS assay to discriminate between sc carrier (sc/+) and non-carrier (+/+) individuals. ImplicationsThis project confirmed that featherless broiler strains grow efficiently with high yield and quality of breast meat, even under warm rearing conditions that significantly depress the overall performance of CCB. Therefore, broiler meat production in hot regions and climates can be substantially improved by introducing the featherless gene into contemporary commercial broiler stocks. This approach has become more feasible with the development of dCAPS assay. A novel modification of the PCR protocol (using whole blood samples instead of extracted DNA) may contribute to the efficient development of commercial featherless broiler strains. Such strains will allow expansion of the broiler meat production in developing countries in warm climates, where energy intensive environmental control of rearing facilities are not economical and easily achievable.
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Kudin, Roman, Prabhat Chand, and Anura Bakmeedeniya. Mitigating Nitrogen Oxides Exhaust Emissions from Petrol Vehicles by Application of a Fuel Additive. Unitec ePress, August 2020. http://dx.doi.org/10.34074/rsrp.083.
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This research has been commissioned by Eco Fuel Global Limited, a New Zealand-based company, to further evaluate the effects of their fuel-additive product on the tailpipe exhaust emissions of petrol cars. At the time this research was conducted (end of 2018), the product was still in development and had not been released to the market. Prior to the testing in this research, an initial pilot test was done for the same product on a single car (Nissan Pulsar 1998), which showed favourable results, with a reduction in hydrocarbons and oxides of nitrogen at the tailpipe by more than 70%. The current research included five test cars, all running on RON 95 fuel, with the years of manufacture ranging between 1994 and 2006, and the odometer readings between 112,004 km and 264,001 km. The effects of the fuel-additive product were assessed by comparing the emissions from a car running on standard fuel with the emissions from the same car after it completed a road run (250±20 km) on the additive-treated fuel. The exhaust emissions were measured using the AVL series 4000 Emission Tester, which analyses five components: carbon monoxide (CO), carbon dioxide (CO2), oxides of nitrogen (NOX), hydrocarbons (HC) and oxygen (O2). The most noticeable outcome of using the fuel-additive product was the reduction in the concentration of oxides of nitrogen in the tailpipe exhaust (by up to 27.7%), when compared with the same cars running on standard fuel. In addition, the results showed a decrease in residual oxygen concentration, which normally indicates more complete utilisation of O2 as an oxidising agent. Mitigating Nitrogen Oxides Exhaust Emissions from Petrol Vehicles by Application of a Fuel Additive Dr Roman Kudin, Prabhat Chand and Anura Bakmeedeniya 2 The changes for other emission parameters were either relatively small (below 1%) or were not statistically significant. The application of such fuel-additive products could be beneficial for mitigating nitrogen oxides exhaust emissions from petrol vehicles in countries with ageing car fleets. These include New Zealand, which has a relatively high proportion of old cars in use, with no government-run scrappage scheme, and without a mandatory objective emissions testing.
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Rossi, Ruggero, David Jones, Jaewook Myung, Emily Zikmund, Wulin Yang, Yolanda Alvarez Gallego, Deepak Pant, et al. Evaluating a multi-panel air cathode through electrochemical and biotic tests. Engineer Research and Development Center (U.S.), December 2022. http://dx.doi.org/10.21079/11681/46320.
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To scale up microbial fuel cells (MFCs), larger cathodes need to be developed that can use air directly, rather than dissolved oxygen, and have good electrochemical performance. A new type of cathode design was examined here that uses a “window-pane” approach with fifteen smaller cathodes welded to a single conductive metal sheet to maintain good electrical conductivity across the cathode with an increase in total area. Abiotic electrochemical tests were conducted to evaluate the impact of the cathode size (exposed areas of 7 cm², 33 cm², and 6200 cm²) on performance for all cathodes having the same active catalyst material. Increasing the size of the exposed area of the electrodes to the electrolyte from 7 cm² to 33 cm² (a single cathode panel) decreased the cathode potential by 5%, and a further increase in size to 6200 cm² using the multi-panel cathode reduced the electrode potential by 55% (at 0.6 A m⁻²), in a 50 mM phosphate buffer solution (PBS). In 85 L MFC tests with the largest cathode using wastewater as a fuel, the maximum power density based on polarization data was 0.083 ± 0.006Wm⁻² using 22 brush anodes to fully cover the cathode, and 0.061 ± 0.003Wm⁻² with 8 brush anodes (40% of cathode projected area) compared to 0.304 ± 0.009Wm⁻² obtained in the 28 mL MFC. Recovering power from large MFCs will therefore be challenging, but several approaches identified in this study can be pursued to maintain performance when increasing the size of the electrodes.
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Regan, Jack, and Robin Zevotek. Study of the Fire Service Training Environment: Safety and Fidelity in Concrete Live Fire Training Buildings. UL Firefighter Safety Research Institute, July 2018. http://dx.doi.org/10.54206/102376/wxtw8877.
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The goal of fire service training is to prepare students for the conditions and challenges that they face on the fireground. Among the challenges that firefighters routinely face on the fireground are ventilation-controlled fires. The hazard of these fires has been highlighted by several line-of-duty deaths and injuries in which a failure to understand the fire dynamics produced by these fires has been a contributing factor. The synthetic fuels that commonly fill contemporary homes tend to result in ventilation-controlled conditions. While synthetic fuels are common on the residential fireground, the fuels that firefighters use for fire training are more often representative of natural, wood-based fuels. In order to better understand the fire dynamics of these training fires, a series of experiments was conducted in a concrete live fire training building in an effort to evaluate the fidelity and safety of two training fuels, pallets and OSB, and compare the fire dynamics created by these fuels to those created by a fuel load representative of a living room set with furniture items with a synthetic components. Additionally, the effects of the concrete live fire training building on the fire dynamics were examined. The two training fuel loads were composed of wooden pallets and straw, and pallets, straw, and oriented strand board (OSB). The results indicated that the high leakage area of the concrete live fire training building relative to the fuel load prevented the training fuel packages from becoming ventilation-controlled and prevented the furniture package from entering a state of oxygen-depleted decay. The furniture experiments progressed to flashover once ventilation was provided. Under the conditions tested, the wood based fuels, combined with the construction features of this concrete live fire training building, limited the ability to teach ventilation-controlled fire behavior and the associated firefighting techniques. Additionally, it was shown that the potential for thermal injury to firefighters participating in a training evolution existed well below thresholds where firefighter PPE would be damaged.
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Hochman, Ayala, Thomas Nash III, and Pamela Padgett. Physiological and Biochemical Characterization of the Effects of Oxidant Air Pollutants, Ozone and Gas-phase Nitric Acid, on Plants and Lichens for their Use as Early Warning Biomonitors of these Air Pollutants. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7697115.bard.
Full textAbstract:
Introduction. Ozone and related oxidants are regarded as the most important phytotoxic air pollutant in many parts of the western world. A previously unrecognized component of smog, nitric acid, may have even greater deleterious effects on plants either by itself or by augmenting ozone injury. The effects of ozone on plants are well characterized with respect to structural and physiological changes, but very little is known about the biochemical changes in plants and lichens exposed to ozone and/or HNO3. Objectives.To compare and contrast the responses of crop plants and lichens to dry deposition of HNO3 and O3., separately, and combined in order to assess our working hypothesis that lichens respond to air pollution faster than plants. Lichens are most suitable for use as biomonitors because they offer a live-organism-based system that does not require maintenance and can be attached to any site, without the need for man-made technical support systems. Original Immediate aims To expose the tobacco (Nicotiana tabacum L.) cultivar Bel-W3 that is ozone supersensitive and the ozone sensitive red kidney bean (Phaseolusvulgaris) and the lichen Ramalinamenziesii to controlled HNO3 and O3 fumigations and combined and to follow the resulting structural, physiological and biochemical changes, with special reference to reactive oxygen species related parameters. Revised. Due to technical problems and time limitations we studied the lichen Ramalinamenziesii and two cultivar of tobacco: Bel-W3 that is ozone supersensitive and a resistant cultivar, which were exposed to HNO3 and O3 alone (not combined). Methodology. Plants and lichens were exposed in fumigation experiments to HNO3 and O3, in constantly stirred tank reactors and the resulting structural, physiological and biochemical changes were analyzed. Results. Lichens. Exposure of Ramalinamenziesiito HNO3 resulted in cell membrane damage that was evident by 14 days and continues to worsen by 28 days. Chlorophyll, photosynthesis and respiration all declined significantly in HNO3 treatments, with the toxic effects increasing with dosage. In contrast, O3 fumigations of R. menziesii showed no significant negative effects with no differences in the above response variables between high, moderate and low levels of fumigations. There was a gradual decrease in catalase activity with increased levels of HNO3. The activity of glutathione reductase dropped to 20% in thalli exposed to low HNO3 but increased with its increase. Glucose 6-phosphate dehydrogenase activity increase by 20% with low levels of the pollutants but decreased with its increase. Tobacco. After 3 weeks of exposure of the sensitive tobacco cultivar to ozone there were visible symptoms of toxicity, but no danmage was evident in the tolerant cultivar. Neither cultivar showed any visible symptoms after exposure to HNO3.In tobacco fumigated with O3, there was a significant decrease in maximum photosynthetic CO2 assimilation and stomatal conductance at high levels of the pollutant, while changes in mesophyll conductance were not significant. However, under HNO3 fumigation there was a significant increase in mesophyll conductance at low and high HNO3 levels while changes in maximum photosynthetic CO2 assimilation and stomatal conductance were not significant. We could not detect any activity of the antioxidant enzymes in the fumigated tobacco leaves. This is in spite of the fact that we were able to assay the enzymes in tobacco leaves grown in Israel. Conclusions. This project generated novel data, and potentially applicable to agriculture, on the differential response of lichens and tobacco to HNO3 and O3 pollutants. However, due to experimental problems and time limitation discussed in the body of the report, our data do not justify yet application for a full, 4-year grant. We hope that in the future we shall conduct more experiments related to our objectives, which will serve as a basis for a larger scale project to explore the possibility of using lichens and/or plants for biomonitoring of ozone and nitric acid air pollution.