Дисертації з теми "Double Nickel"
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Teeters-Kennedy, Shannon Marie. "Infrared surface plasmons in double stacked nickel microarrays lipid bilayer systems /." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1180531191.
Повний текст джерелаTeeters-Kennedy, Shannon M. "Infrared Surface Plasmons in Double Stacked Nickel Microarrays: Lipid Bilayer Systems." The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1180531191.
Повний текст джерелаBarbaroux, Romain. "Développement d'un procédé hydrométallurgique de récupération du nickel." Thesis, Vandoeuvre-les-Nancy, INPL, 2010. http://www.theses.fr/2010INPL087N/document.
Повний текст джерелаThis research has been done in the context of the design of an original method aiming at obtaining high added value products of nickel, combining phytoextraction and valorization. Phytoextraction is conducted with the hyperaccumulating plant Alyssum murale, endemic species of serpentine soils in Albania. Serpentine soils can be considered as secondary resources: they contain high concentrations of nickel, which are not high enough for conventional mining techniques. The plant Alyssum murale can extract and concentrate nickel in its tissues. Nickel present in the biomass could be almost totally solubilized in batch reactor and with a 3 step countercurrent process. This leaching produced a solution containing nickel bound to organic molecules and other metals and organic compounds as well. Direct separation processes (e.g. selective precipitation and electrowinning) did not enable us to obtain nickel. Two methods have been investigated: (i) extraction by an organic nickel –selective solvent (Cyanex 272), extraction by an aqueous solution and electrowinning and (ii) crystallization of a double salt, nickel ammonium sulfate, from a leaching solution obtained from biomass ashes. Nickel products were characterized by different techniques. A technico-economical study showed the high commercial potential of the double salt production
Göllner, Martin [Verfasser], and Bert [Akademischer Betreuer] Nickel. "Double-Gate Pentacene Thin Film Transistors for Biosensing / Martin Göllner. Betreuer: Bert Nickel." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2012. http://d-nb.info/102130803X/34.
Повний текст джерелаSong, Hyo-Jin. "Microstructural Evolution and Deformation Mechanisms in Nickel-Base SuperAlloys." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1282059574.
Повний текст джерелаGuéguen, Bleuenn. "Apport de la géochimie isotopique du Nickel à l'étude des dépôts métallifères océaniques." Thesis, Brest, 2013. http://www.theses.fr/2013BRES0089/document.
Повний текст джерелаScientific explorations implemented for around forty years allow to identifying the diversity and the complexity of geological and geochemical processes conducting to metals concentration on the deep seafloor. Fe- and Mn-rich metalliferous deposits such as hydrogenetic and hydrothermal ferromanganese (Fe-Mn) crusts and polymetallic nodules, present various enrichment in elements of economic interests like Ni, Cu, Co, Te, Pt and Rare Earth Elements. Although the mineralogy and geochemistry of these deposits have been largely studied in the literature, metal sources remain poorly determined. Accordingly, understanding the geochemistry of these deposits implies to know which processes are involved in their formation but also to have a better knowledge of the sources (e.g. the continental and hydrothermal fluxes) and their importance in the global oceanic metal biogeochemical cycles. In order to fill this gap, our approach consisted in using metal stable isotope compositions as biogeochemical tracers. This project is organized around two hypotheses, (1) development and utilization of a new geochemical tool, namely Ni isotopes, for tracing metal enrichment sources and processes in oceanic metalliferous deposits; (2) combination of several isotope systematics such as Fe, Pb, Cu, Zn (and Ni) in Fe-Mn crusts as proxies of the deep seawater isotope composition. Upon developing an analytical method for measuring Ni isotopes by MC-ICP-MS and estimating the Ni isotopes variability in natural systems through the characterization of terrestrial reservoirs, we experimentally evaluated Ni isotope fractionation during adsorption on Fe- and Mn-oxyhydroxides since similar processes may potentially occur in natural Fe-Mn deposits. Results indicate that after Ni adsorption, the solid phase is enriched in light Ni isotopes relatively to the solution with fractionation factors (Δ60/58Nimin/sol) varying from -1 ‰ for birnessite, -0.9 ‰ for goethite and -0.4 ‰ for ferrihydrite. These results, and other recent studies, strengthen our hypothesis according to which Ni isotopes variability in Fe- and Mn-rich metalliferous deposits can be explained by enrichment and formation processes during metal incorporation in Fe and Mn mineral phases rather than variations in the isotopic composition of the sources. Thus, hydrogenetic Fe-Mn crusts formed slowly from seawater dissolved metals do not show significant Ni isotope fractionation, whereas hydrothermal deposits formed by relatively rapid processes as a result of hydrothermal inputs exhibit important Ni isotope fractionation
Wang, Teng. "Nickel based nanomaterials for renewable energy conversion and storage application." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/119163/8/Teng_Wang_Thesis.pdf.
Повний текст джерелаDuke, Frédéric. "Low-cycle cyclic fatigue properties of novel nickel-titanium rotary endodontic instruments in the single- and double-curvatures." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54277.
Повний текст джерелаDentistry, Faculty of
Graduate
Lu, Zheng-Ya. "Extraction of copper from copper-iron and copper-nickel-iron sulfide concentrates by a double roast-leach process." Thesis, Lu, Zheng-Ya (1986) Extraction of copper from copper-iron and copper-nickel-iron sulfide concentrates by a double roast-leach process. PhD thesis, Murdoch University, 1986. https://researchrepository.murdoch.edu.au/id/eprint/52722/.
Повний текст джерелаDaugherty, Ryan E. "Electrochemical Deposition of Nickel Nanocomposites in Acidic Solution for Increased Corrosion Resistance." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1011756/.
Повний текст джерелаSwirk, Katarzyna. "Design of new catalysts for chemical CO2 utilization." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS367.
Повний текст джерелаReforming of methane, belonging to the Carbon Capture and Utilization technologies, is considered an attractive route for syngas production. Double-layered hydroxides (DLHs) with Ni, Al2O3, MgO components were reported to have promising properties. Promotion with yttrium, zirconium or cerium also positively influence the catalytic performance. Thus, the goal of this PhD thesis was to evaluate the catalytic behavior of Ni/Mg/Al DLHs promoted with Y, and Zr or Ce in dry reforming of methane (DRM), partial oxidation of methane (POM), partial oxidation combined with methane reforming (CRPOM), and tri-reforming of methane (TRM). The catalysts were characterized by XRD, XRF, N2 sorption, TPR-H2, TPD-CO2, H2 chemisorption, TEM, HRTEM, TGA and Raman spectroscopy and tested in TPSR from 600 to 850°C, and at 700°C for 5h. In DRM, the Y promotion increased Ni dispersion and SBET, especially with 2 wt.%. Zr and Y co-impregnation resulted in the YSZ phase formation leading to better stability. The Zr and Y introduction during co-precipitation step increased the Ni dispersion and the total basicity, similarly as for Ce and Y promoted materials. In the oxidative reforming, HTNi and HTNi-Y2.0 were tested. In POM, both were active and stable with H2/CO≈2.0. CRPOM tests showed higher CH4 conversion, but lower for CO2 as compared to DRM. Addition of O2 in the gas feed greatly contributed to the C removal. The carbon formation was inhibited when CO2/H2O=1 during TRM tests. However, with CO2/H2O=0.5, a high amount of C was formed, and the structural stability of Y-catalyst was negatively influenced as periclase was transformed into hydroxides
Santiago, Kamilla GilÃ. "Estudo da viabilidade econÃmica de revestimentos com as ligas de nÃquel AWS ER NiCrMo-3 e AWS ER NiCrMo-4 em chapas de aÃo ASTM 516 GR60 pelo processo MIG/MAG duplo arame." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11562.
Повний текст джерелаA soldagem de revestimentos de ligas de nÃquel à utilizada pelas indÃstrias de petrÃleo e gÃs como opÃÃo de construÃÃo e reparo de estruturas e equipamentos submetidos em ambiente de condiÃÃes severas com o intuito de apresentar desempenhos necessÃrios de resistÃncia à corrosÃo. Muitos trabalhos foram desenvolvidos com superligas de nÃquel AWS ERNiCrMo-3, AWS ERNiCrMo-4 e AWS ERNiCr-Mo14, para avaliar resistÃncias à corrosÃo e a Ãltima se mostrou bem superior, porÃm o seu custo tambÃm à bem mais elevado que as outras duas. Assim, o trabalho vem aliar a alta produtividade do processo de soldagem MIG/MAG â DA atravÃs da soldagem de revestimentos com as ligas AWS ERNiCrMo-3 e AWS ERNiCrMo-4 na intenÃÃo de se obter uma mistura que apresente tanto a composiÃÃo quÃmica prÃxima a da liga AWS ER NiCr-Mo-14 como desempenho de resistÃncia a corrosÃo, porÃm com menor custo. Estudos exploratÃrios foram realizados por meio de soldagem com simples deposiÃÃo para determinaÃÃo da faixa de velocidade de soldagem entre 50 e 100 cm/min, modo de operaÃÃo da fonte em corrente constante pulsada e gÃs de proteÃÃo ArgÃnio puro. Os revestimentos foram soldados com menor energia (7,5 kJ/cm), tecimento triangular, eletrodos posicionados um atrÃs do outro em relaÃÃo a velocidade de soldagem e sem defasagem entre as correntes. Nessa etapa variou-se Ãngulo de ataque e o percentual de sobreposiÃÃo dos cordÃes. A melhor condiÃÃo apresentada foi menor diluiÃÃo, 9,75%, e elevado reforÃo, 3,92 mm, sendo essa obtida utilizando-se a tocha inclinada de 15Â, e sobreposiÃÃes de 50%. A relativa baixa diluiÃÃo encontrada e o elevado reforÃo reduziram a necessidade de uma segunda camada, o que torna o processo uma boa opÃÃo para operaÃÃes de revestimento para indÃstria de petrÃleo e gÃs.
Weld overlayâs Nickel based alloy are used by the oil and gas industry as an option for construction and repair of structures and equipment subjected to severe environment conditions with the purpose to provide performance required like for corrosion resistance. Many works have been developed with Nickel based superalloys AWS ERNiCrMo-3, AWS ERNiCrMo-4 e AWS ERNiCrMo-14, evaluating among several characteristics the last alloy proved to be upper, but their cost is also higher than the other two. Therefore the present work intends to combine the high productivity of GMAW double wire for welding overlay applications using alloy with AWS ERNiCrMo-3, AWS ERNiCrMo-4 with the intention of obtain a mixture presenting both chemical composition similar to the AWS ER NiCrMo-14 such as corrosion resistance performance, but with less cost. Exploratory studies were performed by means of welding with simple deposition to determine the range of welding speed between 50 and 100 cm / min, the operating mode of the source constant current and pulsed pure argon shielding gas. The coatings were welded with low energy (7,56 kJ/cm), triangle weaving, electrodes positioned one behind the other in relation to the welding speed, without out of phase the currents. This step was varied angle of attack and the percentage of overlap the weld beads. The best condition was presented lower dilution, 9.75%, and a high thickness 3.92 mm and that obtained using the torch inclined at 15 Â and overlap of 50%. The relatively low dilution and high thickness found reduced the need for a second coating, which makes the process a good option for coating operations.
Zhang, Xin. "Procédé hydrométallurgique pour la valorisation du nickel contenu dans les plantes hyperaccumulatrices." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0172/document.
Повний текст джерелаSome plants, known as hyperaccumulators, are able to develop on metal containing soils and to accumulate these metals at high concentrations in shoots. Biomass incineration leads to ash containing 10 to 25 wt % nickels, greater than in some mineral ores. This work follows a research that has been carried out by the team for several years, which has resulted in a patent on the hydrometallurgical production of the double salt ammonium and nickel hexahydrate (ANSH) from the biomass of Alyssum murale. It aims at improving the synthesis method of this salt in order to upscale it at the pilot scale and explore new methods leading to new products. The manuscript begins with a bibliographic review on phytomining from hyperaccumulators to metal recycling processes, essentially focused on nickel. Then ca 15 hyperaccumulator plants (genus Alyssum, Leptoplax and Bornmuellera) collected in Greece or Albania have been compared, in the objective of phytomining. Nickel concentrations were measured in the plant organs and in the ashes after combustion. The three types of plants are of great interest for the technology, they contain 1 to 3 wt % of nickel and the ashes 15 to 20%. The hydrometallurgical process of ANSH production was investigated step by step to optimize each step to produce a salt of high purity, to decrease materials and energy consumption and to minimize effluent and waste production. The process was thus improved. Eventually, new ideas have been tested for new processes and nickel products. The obtained results and the current dynamics prove the interest of phytomining and announce its imminent development
Turano, Stephan Parker. "Carbon Nanotubes chemical vapor deposition synthesis and application in electrochemical double layer supercapacitors /." Thesis, Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-02242005-094827/unrestricted/turano%5Fstephan%5Fp%5F200505%5Fmast.pdf.
Повний текст джерелаReady, Jud, Committee Co-Chair ; Carter, Brent, Committee Co-Chair ; Snyder, Bob, Committee Member ; Wang, Zhong Lin, Committee Member. Includes bibliographical references.
Papadopoulos, Konstantinos. "Investigation of magnetic order in nickel-5d transition metal systems." Thesis, Uppsala universitet, Molekyl- och kondenserade materiens fysik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-383009.
Повний текст джерелаKubecka, Petr. "Etude du comportement d'alliages passivables, acier duplex et alliage fer-nickel, soumis a l'action combinée du frottement et de la corrosion." Châtenay-Malabry, Ecole centrale de Paris, 1998. http://www.theses.fr/1998ECAP0584.
Повний текст джерелаDeb, Tapash K. "Bioinspired Redox Active Pseudotetrahedral Ni(II) Thiolate and Phenolate Complexes: Synthesis, Characterization, Alkylation Kinetics and Molecular Oxygen Activation." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1377256181.
Повний текст джерелаMazzei, Lorenzo. "Elettrodi modificati con nanomateriali di carbonio: ottimizzazione della sintesi di idrossidi doppi a strati." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15844/.
Повний текст джерелаRibet, Solange. "Propriétés catalytiques d'hydroxydes doubles lamellaires multicomposants (Co, Ni, Mg, Al). Application à l'hydrogénation de l'acétonitrile." Montpellier 2, 1999. http://www.theses.fr/1999MON20051.
Повний текст джерелаRolland, Alice. "Synthèses et caractérisations de précurseurs de catalyseurs de type métaux supportés : Les hydroxydes doubles lamellaires : appliqués à la semi-hydrogénation de l'adiponitrile." Montpellier 2, 2002. http://www.theses.fr/2002MON20028.
Повний текст джерелаLi, Min. "Preparation of composite materials for high-performance supercapacitors." Thesis, Lille 1, 2020. http://www.theses.fr/2020LIL1I011.
Повний текст джерелаSupercapacitors, as energy storage devices, have drawn great attention in our daily life to bridge the gap between batteries and capacitors. Therefore, the preparation of high-performance material electrodes for supercapacitors plays a vital role in the future technological developments. In this context, layered double hydroxides (LDHs) and Ni(OH)2 have been recognized as promising electrodes for supercapacitors, owing to their fast redox reaction and battery-type behavior.The Chapter 1 of my PhD work gives a brief historic overview, principles and mechanism of energy storage, electrode materials of supercapacitors and the corresponding characterization methods. In Chapter 2, after a brief introduction on LDHs and their investigation as electrode materials in supercapacitors, we summarize our results obtained on Ni-based LDHs as electrodes for supercapacitors. Firstly, NiFe LDHs on Ni foam (NF) coated with reduced graphene oxide (NiFe LDHs/rGO/NF) was prepared by electrochemical deposition method. NiFe LDHs/rGO/NF achieved enhanced specific capacity (585 C g-1 at a current density of 5 A g-1). Additionally, a flexible asymmetric supercapacitor was assembled using NiFe LDHs/rGO/NF as the cathode and mesoporous carbon (MC) coated on NF as the anode. The supercapacitor exhibited an energy density of 17.71 Wh kg-1 at a power density of 348.49 W kg-1. Secondly, NiAl LDHs coated on carbon spheres (CS) supported by Ni foam (NiAl LDHs@CS/NF) electrodes were synthesized by a facile hydrothermal method. The performance of the prepared materials as binder-free electrodes in supercapacitors was assessed. The NiAl LDHs@CS/NF electrode achieved the largest areal capacity (1042 mC cm-2), as compared to the areal capacity values attained by NiFe LDHs@CS/NF (705.8 mC cm-2) and NiCr LDHs@CS/NF (814.9 mC cm-2) at 1 mA cm-2. Therefore, a hybrid supercapacitor device comprising NiAl LDHs@CS/NF as the positive electrode and N-doped reduced graphene/NF as the negative electrode was assembled, which attained an energy density of 43 μWh cm−2 at a power density of 0.805 mW cm−2. The hybrid supercapacitor was successfully applied to operate a windmill device continuously for 32 s. Finally, NiMnCr LDHs-carbon spheres modified Ni foam (NiMnCr LDHs@CS/NF) nanocomposite was prepared using a two-step hydrothermal process and exhibited a high specific capacity of 569 C g-1 at 3 A g-1 with good reversibility and stability. Furthermore, a hybrid supercapacitor was fabricated using NiMnCr LDHs@CS/NF as the positive electrode and FeOOH coated on NF (FeOOH/NF) as the negative electrode. The energy storage device reached an energy density of 48 Wh kg-1 at a power density of 402.7 W kg-1. In Chapter 3, Ni(OH)2@CuO@Cu foam binder-free electrodes were fabricated by a two-step process at room temperature with various deposition times (30, 50, 90, 150 and 200s). Among all the samples, Ni(OH)2@CuO@Cu-150 exhibited the largest areal capacity of 7063 mC cm-2 at 20 mA cm-2, and was therefore chosen as the positive electrode in a hybrid supercapacitor. Using N-doped reduced graphene oxide on nickel foam (N-rGO/NF) as the negative electrode, a hybrid supercapacitor was assembled. It displayed good flexibility, cycling stability and high areal energy density of 130.4 μWh cm−2 at a power density of 1.6 mW cm−2.In conclusion, all the results obtained in this thesis imply the promising potential application of Ni-based hydroxide composites as energy storage devices and provide valuable highlights to the exploration of new composite materials for supercapacitor electrodes in future works (Chapter 4)
Pierre-Louis, Olivier. "Intérêt de la double fonctionnalité SP ALDH et de la modélisation des niches hématopoïétiques pour une meilleure approche de la régulation de l'hématopoïèse." Paris 11, 2009. http://www.theses.fr/2009PA11T101.
Повний текст джерелаLauzeral, Christine. "Prédiction du potentiel d'invasion des espèces non natives par des modèles de niche : approches méthodologiques et applications aux poissons d'eau douce sur le territoire français." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1876/.
Повний текст джерелаFreshwaters are among the most anthropogenicaly threatened ecosystems in the world. They especially face serious threats due to invasive species. Efforts are thus needed to control invasions and increase the accuracy of the models used to predict the potential distribution of invasive species. We showed that: - the area of the observed distribution, and thus the area of the distribution predicted by correlative models, increases exponentially with the spatial grain of the data. However, model quality is little affected by the grain of the data and decreases only for the largest grains. - coarse-grained occurrence data remain useful in identifying the species that experience niche shifts. - most of the six fish species that we have studied were able to establish in France under climate change, even without niche shift. - the iterative ensemble modeling method that we developed increases the accuracy of predictions as soon as the occurrence data set contained abundant non environmental absences. This new method is of interest for invasive species niche modeling but also to model the distribution of difficult to detect or endangered species
Subalusky, Amanda Lee. "The role of seasonal wetlands in the ecology of the American alligator." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1640.
Повний текст джерелаGreulich, Sabine. "Compétition, perturbations et productivité potentielle dans la définition de l'habitat d'espèces rares : étude expérimentale du macrophyte aquatique Luronium natans (L) Rafin." Lyon 1, 1999. http://www.theses.fr/1999LYO10077.
Повний текст джерелаTisseuil, Clément. "Modéliser l'impact du changement climatique sur les écosystèmes aquatiques par approche de downscaling." Toulouse 3, 2009. http://thesesups.ups-tlse.fr/763/.
Повний текст джерелаThis thesis aimed at assessing the impact of global change on freshwater ecosystems during the 21st century in the Adour Garonne area (SW France). A downscaling approach was developed linking techniques from climate, hydro-chemical and ecological sciences. The main results suggest an increase of high flows in winter as well as more severe low flows in summer. Nitrogen concentrations and thermophile fish species distribution may also increase. Reducing green house gas emissions and modifying agricultural practices (e. G reducing nitrate fertilizers) could reduce the intensity of ecological disturbances. This study is an original contribution to the management of future hydrological and ecological resources
Zhao, Tian. "Effets des invasions biologiques sur les patrons de diversité fonctionnelle et la structure trophique des communautés de poissons d'eau douce." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30120.
Повний текст джерелаUnderstanding the relationship between biodiversity and ecosystem functioning is a central question in modern ecology. This question is particularly crucial in the general context of human perturbations on both biodiversity and ecosystems. Biological invasions are considered as one of the leading causes of the ongoing taxonomic diversity crisis and the modification of ecosystems. This is especially true in freshwater ecosystems since the widespread introductions of non-native fish can modify recipient communities notably by changing the biotic interactions between species. Trophic interactions represent the linkage between the structural characteristics of biodiversity and the functioning of ecosystems, describing the network of species and the energy links between them. Identifying the impacts of non-native fish species on the trophic structure of recipient communities is therefore crucial to estimate how ecosystem functioning and ecosystem services might respond to biological invasions. In the present study, fish communities from 18 gravel pit lakes were selected and monitored during two consecutive years to test the effects of biological invasions on functional diversity patterns and the trophic structure of fish communities. We first investigated the environmental determinants of fish community composition and structure in these gravel pit lakes. Our results demonstrated that fish community structure significantly differed between lakes and we notably found that lakes highly managed for angling hosted higher levels of taxonomic diversity. We also found that native and non-native species were dominant in lakes with different environmental conditions, while management practices play a critical role in shaping fish species composition. Overall, these findings demonstrated that fish community composition followed a predictable shift along an environmental gradient linked to the natural maturation of gravel pit lakes and the associated human practices. Second, we quantified the importance of intraspecific variability in functional traits in a model species, the largemouth bass (Micropterus salmoides). We sampled a whole population in a private pond and found that functional trait variability among individuals within the same population could affect estimates of functional diversity. Moreover, the extremely low overlap for both functional and stable isotope niches between age-classes indicated that different age classes within a species should be considered as distinct functional entities. We also demonstrated the existence of a significant correlation between functional traits and stable isotope values, suggesting the existence of a linkage between trophic specialization and differences in functional traits within each life stage. Third, incorporating intraspecific variation in functional traits at the community level, we examined the functional attributes of fish communities in the studied lakes. Our results demonstrated that native and non-native fish significantly differed in terms of functional traits. We also demonstrated that niche partitioning was the principal mechanism allowing the coexistence of native and non-native fish with similar functional traits
Buisson, Laetitia. "Poissons des rivières françaises et changement climatique : impacts sur la distribution des espèces et incertitudes des projections." Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT005A/document.
Повний текст джерелаClimate change and its impact on biodiversity are receiving increasing attention from scientists and people managing natural ecosystems. Indeed, climate has a major influence on the biology and ecology of fauna and flora, from physiology to distribution. Climate change may thus have major consequences on species and assemblages. Among freshwater ecosystems, stream fish have no physiological ability to regulate their body temperature and they have to cope with streams' hydrological variability and strong anthropogenic pressures. Yet their response to current and future climate change has been poorly studied. The aim of this PhD thesis is to assess the potential impact of climate change on fish in French streams, mainly on species distribution and assemblages' structure. Data provided by the Office National de l'Eau et des Milieux Aquatiques combined with a modelling approach based on species' ecological niche (i.e., distribution models) have been used. Several sources of uncertainty have also been considered in an ensemble modeling framework in order to account for the variability between projected impacts and to provide reliable estimates of such impact. First, we have identified the main environmental factors that determine the spatial distribution of fish species within river networks. Overall, it appears that a combination of both climatic variables and variables describing the local habitat and its position within the river network is important to explain the current species distribution. Moreover, each fish species responded differently to the environmental factors. Second, we have highlighted that the choice of the statistical method used to model the fish ecological niche is crucial given that the current and future patterns of distribution predicted by different statistical methods vary significantly. The statistical method appears to be the main source of uncertainty, resulting in more variability in projections than the global circulation models and greenhouse gas emission scenarios. The variability between predictions from several statistical methods can be taken into account by a consensus approach. Consensual predictions based on the computation of the average of the whole predictions ensemble have achieved accurate predictions of the current species distribution and assemblages' composition. We have therefore selected this approach to assess the potential impacts of climate change on fish in French streams at the end of the 21st century with the highest degree of confidence. We have found that most fish species could be sensitive to the future climate modifications. Only a few cold-water species (i.e., brown trout, bullhead) could restrict their distribution to the most upstream parts of river networks. On the contrary, cool- and warm-water fish species could colonize many newly suitable habitats and expand strongly their distribution. These changes of species distribution could lead to a rearrangement of fish assemblages both at the taxonomic and functional levels. An increase in local diversity together with an increase in regional similarity (i.e., homogenization) are therefore expected. All these results bring new insights for the understanding of stream fish species distribution and expected consequences of climate change. This work thus provides biodiversity managers and conservationists with a basis to take efficient preservation measures. In addition, methodological developments considered in this PhD thesis are an important contribution to the improvements of projections by statistical models of species distribution and to the quantification of their uncertainty
Cogerino, Laurent. "Les rives aquatiques de grands cours d'eau : caractérisation mésologique et faunistique." Lyon 1, 1989. http://www.theses.fr/1989LYO10136.
Повний текст джерелаYang, Hui_Chun, and 楊慧君. "The Research of Nickel-Containing Double Strand Polymer." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/10818171542395395035.
Повний текст джерела國立臺灣大學
化學研究所
90
The synthesis of norbornene containing organonickel thiolato complexes [Ni(Cp)2(SR)2] is described. The Dlels-Alder reaction of cyclopentadiene and maleic imide yields the norbornene derivative. Reduction of the imide and ester groups using lithium aluminum hydride affords tertiary amine and hydroxy methyl groups. Transformation of the terminal hydroxy group into the corresponding mercaptan is achieved by treatment of the alcohol with phosphorus(Ⅴ) pentasulfide. Reaction of bis(cyclopentadienyl)nickel with the mercaptan gives the corresponding monomer by means of the Grubbs catalyst Cl2(PCy3)2Ru=CHPh yields the double strand polymer. XRD is employed for structural elucidation. It has been shown that the polymer may adopt regular architecture with a regular spacing 5.3 Å which would be attributed to the Ni─Ni distance between two monomeric units. Similar distance is observed by EXAFS measurements. TEM shows that the polymer has bundle structure. These evidences appear to be consistent with a structure of a double strand polymer.
Alikarami, Mohammad. "Dynamic impedance studies of oxidation of nickel and glycerol at nickel electrodes." Thesis, 2019. http://hdl.handle.net/1828/10788.
Повний текст джерелаGraduate
2019-10-23
Ni, Liang-Chieh, and 倪亮傑. "Investigation of Micro Double Slip Model by Tension Test of Pure Copper and Nickel." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/55300657255671037590.
Повний текст джерела國立臺灣大學
土木工程學系
86
The research of this thesis includes two parts: double-slip model and micro tension test. The aim is to relate the microscopic deformation characteristics of polycrystalline materials, especially the slip line orientation, with their macroscopic stress-strain behavior. To this end we performed micro tension tests on pure copper and nickel foil specimens, observing the changing slip band orientations in grains and recorded the time histories of loading and elongation, and then compared the experimental data with those simulated by a double-slip model. The planar double-slip models for polycrystal plasticity have been studied by many scholars and in this thesis a model recently developed by H.-K. Hong and C.-S. Liu is presented. Our model features that the slip line orientations are evolving; moreover, we are able to obtain the closed-form solutions of the slip line orientation and of the orientation distribution function (ODF) under constant velocity gradient and constant hardening, and to prove analytically the normalization condition of the ODF. The micro tension tests were executed using the micro-forcing-heating device and micro-recorder-image analyzer system, which were originally designed by H.-K. Hong and C.-G. Cheng and updated in this thesis work about its power system, changing from an hydraulic actuator to a servomotor, and its image-processing system, changing from an analogy type to a digital type with improved software. In the tests the foil specimens of pure nickel and copper were gradually loaded toward final failure and the evolution of the surfaces of the specimens including grain boundaries and slip bands inside grains were simultaneously observed and recorded through microscope and CCD camera. Comparison with the experimental data shows that the double-slip model is capable of relating the particular microscopic evolution with the macroscopic stress-strain relationship to a certain degree.
Tsai, Yi-Ying, and 蔡宜穎. "Nickel iron layered double hydroxide derived bifunctional oxygen electrode catalyst for rechargeable zinc/air batteries." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/qwd872.
Повний текст джерела國立臺灣科技大學
化學工程系
106
In recent years, rechargeable zinc-air batteries have attracted much attention owing to its high energy density, promising safety, and economic viability. In air electrode, bi-functional electrocatalysts are desirable since the dual functionality of the oxygen evolution reaction (OER) and oxygen oxygen reduction reaction (ORR) are required on the same electrode under charging and discharging processes, respectively. Unfortunately, both ORR catalyst Pt/C and OER catalyst IrO2 don’t have bifunctional property. The high cost of precious Pt/C and IrO2 catalysts also limit their wide spread application. In the light of this, this work provides a promising bi-functional electrocatalyst with earth-abundant elements to enable the oxygen conversion reaction efficiently. Carbon supported NiFe layered double hydroxide (NiFe LDH/C) can be synthesized by a facile hydrothermal method which can precisely control the catalyst’s composition. Then, the optimal NiFe LDH/C was used as precursor and further reduced to bi-functional catalyst by hydrogen reduction and thermal ammonolysis. The results show that NiFe/NiFeN/NC nanocomposites, characterized by duel electroactive sites for OER and ORR, can be simultaneously derived by thermal ammonolysis process. According to the electrochemical measurements by linear sweep voltammetry (LSV), NiFe/NiFeN/NC nanocomposite calcined in ammonia at 500 oC demonstrates excellent activities for oxygen conversion reaction, when compared to NiFe LDH and NiFe/C. Its overpotential △E between the ORR current density of 3 mA cm−2 and OER current density of 10 mA cm−2 is 0.91 (V). In the stability test, a chronoamperometry method was used in 0.1 M KOH. After 6 hours, NiFe/NiFeN/NC catalyst calcined at 500 oC showed high stability with a decline of current of 8.9% and 14.1% in OER and ORR, comparable to 29.1% for IrO2 and 7.7% for Pt/C, respectively. In addition, the ORR stability test in 1 M KOH showed that the activity decayed 18.4% for NiFe/NiFeN/NC, whereas 23.1% for Pt/C. This indicates that the composite catalyst is more suitable for operations under harsh environments. This study further attempts to establish a rechargeable zinc-air battery test platform and analyze material performance. NiFe/NiFeN/NC shows good stability and its performance is comparable to that of Pt/C+IrO2, confirming its bi-functional property. Considering the cost and mass production, NiFe/NiFeN/NC offers more advantages than the combination of noble materials with Pt/C and IrO2. Keywords:Alkaline, Bifunctional electrocatalyst, Layered double hydroxide, N-doped carbon, Rechargeable zinc-air battery.
Pult, Jonas Robert Wilhelm. "Präparation gekrümmter Wurzelkanäle mit drei Nickel-Titan-Systemen - eine Mikro-CT-Studie." Doctoral thesis, 2021. http://hdl.handle.net/21.11130/00-1735-0000-0005-1599-7.
Повний текст джерелаSheng-YiWang and 汪昇毅. "Development of high performance pH sensors based on nickle oxide nanostructures on Si platform with a double-fold surface roughening." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/g6j7vv.
Повний текст джерела