Дисертації з теми "Potential of hydrogen"
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Johansson, Emil. "Synthesis and Characterisation of Potential Hydrogen Storage Materials." Doctoral thesis, Uppsala universitet, Fysik III, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4509.
Повний текст джерелаVerstraete, Dries. "The Potential of Liquid Hydrogen for long range aircraft propulsion." Thesis, Cranfield University, 2009. http://hdl.handle.net/1826/4089.
Повний текст джерелаBillet, Beau. "Lightweight Intermetallics with Laves Structures as Potential Hydrogen Storage Materials." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1357330819.
Повний текст джерелаMacSween, Jeffrey Vanek. "Investigating the microwave-hydrogen peroxide treatment process for potential commercialization." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/55365.
Повний текст джерелаApplied Science, Faculty of
Civil Engineering, Department of
Graduate
Mcdermott, Morgan Marie. "The Remineralization Potential of Nano-Hydroxyapatite in Hydrogen Peroxide Whitening Mouthwash." Walsh University Honors Theses / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=walshhonors1461323620.
Повний текст джерелаLong, Tyler Richard. "Synthesis of polymers with the potential to release H2S: polydicyclopentadiene nanoporous membranes." Diss., University of Iowa, 2014. https://ir.uiowa.edu/etd/4682.
Повний текст джерелаOlson, Jared K. "Ab Initio Search for Novel BxHy Building Blocks with Potential for Hydrogen Storage." DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/844.
Повний текст джерелаHoy, Jason Michael. "Syntheses of Aluminum Amidotrihydroborate Compounds and Ammonia Triborane as Potential Hydrogen Storage Materials." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1260474478.
Повний текст джерелаZhurakovskyi, Oleksandr. "NOVEL DUAL LEWIS ACID - LEWIS BASE BINDERS AS POTENTIAL HYDROGEN AND CARBONYL ACTIVATORS." Thesis, The University of Arizona, 2010. http://hdl.handle.net/10150/193458.
Повний текст джерелаSorbie, Natalie. "Synthesis and structure of group I and II nitrides as potential hydrogen stores." Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/3284/.
Повний текст джерелаBloss, Elaine. "Diffusion of solid molecular hydrogen and chemical potential changes in submonolayer helium flow." Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324134.
Повний текст джерелаIshibashi, Jacob Shotaro Afaga. "BN Isosteres of Acenes for Potential Applications in Optoelectronic Devices." Thesis, Boston College, 2017. http://hdl.handle.net/2345/bc-ir:107613.
Повний текст джерелаThis dissertation describes progress in the field of polycyclic boron- nitrogen-containing systems, especially for potential application in organic-based optoelectronic devices and hydrogen storage materials. The replacement of a BN unit for a CC unit organic compounds (BN/CC isosterism) can have a profound effect on the electronic structure and even function of a given molecular topology without changing its physical structure very much. Direct comparison between a BN-containing molecule and its direct all-carbon analogue is crucial to establishing the origin of these differences. The synthesis and optoelectronic characterization of boron- nitrogen-containing analogues of naphthalene, anthracene, and tetracene are disclosed. Also examined herein is the aromatic Claisen rearrangement applied to an azaboryl allyl ether. Finally, the chemistry of saturated BN heterocycles, including an iridium-catalyzed transfer dehydrogenation method for synthesizing BN-fused azaborines. Also disclosed is the actual application of these cyclic amine-boranes in supplying hydrogen for a proton exchange membrane (PEM) fuel cell
Thesis (PhD) — Boston College, 2017
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
Wannerberg, Karin. "Evaluation of Odomin and potential factors reducing the hydrogen sulphide levels in sewage systems." Thesis, KTH, Maskinkonstruktion (Inst.), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-175675.
Повний текст джерелаXylem Inc. utvecklar pumpar och lösningar för avloppssystem. De har utvecklat ett nytt koncept för att reducera halten av svavelväte, H2S, i avloppsvattnet. H2S är en giftig, illaluktande gas med kännbar lukt vid 0.002-0.2 ppm. Rekommenderat är att utsättas för högst 15 ppm under 15 minuter. Gasen är löslig i vatten och nivåerna ökar med både höga temperaturer och långa uppehållstider i ledningarna. Normalt sätt kan nivåerna av H2S variera mellan 0-1000 ppm, beroende på årstid. Det nya konceptet som kallas Odomin är en för-kammare som installeras uppströms till en pumpstation. I Odomin oxideras H2S till svavelsyra, H2SO4, på våta ytor. Genom att avloppsvattnet kaskaderar på en platta kan gasen komma i kontakt med våta ytor kring plattan. Examensarbetet syftar till att hitta reduktionstalet mellan Odomin 65 och pumpsumpen samt utvärdera 3 faktorer som kan förbättra effekten av Odomin. De undersökta faktorerna är 1) en offeranod av kolstål 2) en minskad inloppsarea för att öka kaskadet och 3) en ökad inre area, för att öka andelen våta ytor, i Odomin. De 3 faktorerna utvärderas med faktorförsök (factorial design). Utvärderingen ger indikationen att ingen av de tre faktorerna påverkar det dagliga medelvärdet på en 5 % signifikansnivå. Offeranoden är den faktor som tenderar minska både medelvärdet och extremvärdet i pump sumpen. Reduktionen av H2S mellan Odomin 65 och pump sumpen är 5.33 och analysen visar att en ökad kaskadeffekt kan öka reduktionen med 55 %. Testerna influeras av flera yttre faktorer vilket påverkar resultatens trovärdighet. Denna analys bör därför repeteras för att resultaten ska kunna verifieras.
Orondo, Peter Omondi. "A theoretical analysis of interstitial hydrogen : pressure-composition-temperature, chemical potential, enthalpy and entropy." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78547.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (p. 371-373).
We provide a first principles analysis of the physics and thermodynamics of interstitial hydrogen in metal. By utilizing recent advances in Density Functional Theory (DFT) to get state energies of the metal-hydrogen system, we are able to model the absorption process fairly accurately. A connection to experiment is made via Pressure-Composition-Temperature (PCT) isotherms, and thermodynamic molar quantities. In the model, we understand the excess entropy of absorbed hydrogen in terms of the change in its accessible microstates. A connection is also made between the entropy and electronic states of interstitial hydrogen. However, our model indicates that this connection is too small to account for experimental results. Therefore, a conclusion is made that the entropy of absorbed hydrogen is mostly (non-ideal) configurational in nature. To model the latter in a manner consistent with experiment, we have explored a new model that posits a weak binding between clusters of hydrogen atoms at neighboring sites. We have developed a formulation and fitted the results to experimental data. We find a least squares fitting of the model to the entropy and enthalpy results in model parameters which seem physically reasonable. The resulting model appears to provide a natural physical explanation for the dependence of the excess entropy on loading.
by Peter Omondi Orondo.
Ph.D.
Svensson, Fredrik. "Potential of reducng the environmental impact of civil subsonic aviation by using liquid hydrogen." Thesis, Cranfield University, 2005. http://dspace.lib.cranfield.ac.uk/handle/1826/10726.
Повний текст джерелаSvensson, Fredrik. "Potential of reducing the environmental impact of civil subsonic aviation by using liquid hydrogen." Thesis, Cranfield University, 2005. http://dspace.lib.cranfield.ac.uk/handle/1826/10726.
Повний текст джерелаNadeem, Muhammad. "Synthesis and characterization of biopolymer nanoapatite composite electrospun bioactive scaffold: A potential application for guided tissue/bone regeneration." University of the Western Cape, 2019. http://hdl.handle.net/11394/7040.
Повний текст джерелаSearch for an ideal scaffold for guided tissue/bone (GTR/GBR) regeneration continues as till now none of the commercially available GTR/GBR membrane fulfils the desired criteria. Currently, a variety of new materials and techniques have been investigated all over the world to improve the properties of GTR/GBR membranes. In the recent past three dimensional bioactive scaffolds composed of natural polymers have gained enormous popularity as potential future GTR/GBR devices. Electrospinning has emerged as one of the relatively simple, cost effective and efficient technique to fabricate three dimensional nanofibrous scaffolds in the field of tissue engineering. The rationale of this project is to investigate the natural polymers based bioactive nanofibrous scaffolds for GTR/GBR applications in the field of Periodontology.
Pritchard, Rachel Elizabeth. "CATALASE ACTIVITY, POTENTIAL VIRULENCE FACTORS, AND THEIR RESPONSE TO OXYGEN IN MYCOPLASMA IOWAE." Miami University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=miami1413553221.
Повний текст джерелаBürchner, Mara [Verfasser], and Ingo [Akademischer Betreuer] Krossing. "Boron ionic liquids as potential hydrogen storage materials = Bor-ionische Flüssigkeiten als potentielle Wasserstoffspeicher-Materialien." Freiburg : Universität, 2014. http://d-nb.info/1123480079/34.
Повний текст джерелаEklund, Melissa. "The potential benefits to balance power shortage in future mobility houses with hydrogen energy storages." Thesis, Uppsala universitet, Elektricitetslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388494.
Повний текст джерелаEvans, Ian Christopher. "Metallated derivatives of ammonia borane with a view to their potential as hydrogen storage materials." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/1702/.
Повний текст джерелаYu, Katayama. "Towards the realization of anion-exchange membrane fuel cell technology: potential of hydrogen-carrier utilization." Kyoto University, 2017. http://hdl.handle.net/2433/227631.
Повний текст джерелаGier, Megan Loran. "The potential neuroprotective effects of two South African plant extracts in hydrogen peroxide-induced neuronal toxicity." University of the Western Cape, 2018. http://hdl.handle.net/11394/6553.
Повний текст джерелаBackground: Oxidative stress induced by reactive oxygen species has been strongly associated with many neurodegenerative diseases (NDDs) and many medicinal plant-derived products have been reported to exert potent antioxidant properties. Sutherlandia frutescens (SF) and Carpobrotus edulis (CE) are two indigenous South African plants with known anti-inflammatory, anti-bacterial, antioxidant and anti-cancer properties. However, the neuroprotective effects of SF and CE have not been extensively studied. Aims: This study was done to investigate the neuroprotective potentials of S. frutescens and C. edulis aqueous extracts on hydrogen peroxide (H2O2)-induced toxicity in an SH-SY5Y neuroblastoma cellular model of oxidative stress injury. Methods: The maximum non-toxic dose (MNTD) of SF and CE against SH-SY5Y cells was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Thereafter, the cells were exposed to 250 μM H2O2 for 3 hours before treatment with the determined MNTDs of SF and CE extracts respectively and the effects of the treatments on caspase-9 protease activity, intracellular ROS levels, mitochondrial membrane permeability (MMP), nitric oxide (NO) activity, intracellular calcium activity and endogenous antioxidant activity in SH-SY5Y cells was evalaluated using caspase activity kits, DCFH-DA assay, rhodamine 123 fluorescent dye, Griess reagent, Fluo-4 direct calcium reagent, Hoechst staining dye, Superoxide dismutase (SOD) colorimetric and Catalase (CAT) assays, respectively.
Crisp, Michael G. "Organoplatinum(II) complexes with hydrogen-bonding functionality and their potential use as molecular receptors for adenine : a thesis submitted for the degree of Master of Science." Title page, abstract and contents only, 2002. http://web4.library.adelaide.edu.au/theses/09SM/09smc932.pdf.
Повний текст джерелаEsswein, Stefan Theo. "Probing protein-ligand interactions via solution phase hydrogen exchange mass spectrometry." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4638.
Повний текст джерелаKammler, Marvin. "MD simulations of atomic hydrogen scattering from zero band-gap materials." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://hdl.handle.net/21.11130/00-1735-0000-0003-C17A-A.
Повний текст джерелаArrage, Andrew Anthony. "Characterization of DNA-repair potential in deep subsurface bacteria challenged by UV light, hydrogen peroxide, and gamma radiation." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-08182009-040256/.
Повний текст джерелаChiuta, Steven. "The potential utilization of nuclear hydrogen for synthetic fuels production at a coal–to–liquid facility / Steven Chiuta." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4840.
Повний текст джерелаThesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2011.
Zhou, Xu. "Synthesis and characterization of rigid nanoporous hypercrosslinked copolymers for high surface area materials with potential hydrogen storage capabilities." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/78048.
Повний текст джерелаMaster of Science
Janke, Svenja Maria. "Theoretical Description of Hydrogen Atom Scattering off Noble Metals." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2016. http://hdl.handle.net/11858/00-1735-0000-0028-87A3-4.
Повний текст джерелаDelloStritto, Daniel Justin. "TRPing up the Balance of Oxidative Stress - Transient Receptor Potential Vanilloid 1’s Role in Diabetic Microvascular Disease." NEOMED Integrated Pharmaceutical Medicine / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ne2mh1469567446.
Повний текст джерелаLinnane, Cathal David. "Investigation of high temperature enhanced hydrogen formation in mineral amended sediment slurries, as a potential novel deep biosphere energy source." Thesis, Cardiff University, 2009. http://orca.cf.ac.uk/54810/.
Повний текст джерелаYe, Xuemin. "The effect of water pH on swimming performance, blood pH, red cell pH, ion concentrations and catecholamine concentrations in plasma, and gill potential in rainbow trout (Salmo gairdneri)." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26676.
Повний текст джерелаScience, Faculty of
Zoology, Department of
Graduate
Foster, Rory 1982. "False optimism for the hydrogen economy and the potential of biofuels and advanced energy storage to reduce domestic greenhouse gas emissions." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32818.
Повний текст джерелаIncludes bibliographical references (leaves 52-53).
Discussion of the general domestic energy situation addresses the motivations which underlie the push for an hydrogen energy economy. The validity of claims about such a hydrogen economy and the official DOE position regarding such are evaluated, and then discarded as overly optimistic given the inherent physics of the required production and transportation processes. Biomass is then introduced as a potential source of greenhouse gas reduction in both stationary and mobile applications for the near term future (10-25 years). Combined renewable power (mainly solar and wind power) and attached energy storage to buffer the inherently fluctuating supply is also discussed, and recommended as potential zero-emission power generation technology for the long-term depending on the advances in photovoltaics, wind power and pumped liquid electrolyte battery technology.
by Rory Foster.
S.B.
Chen, Szu-Lin. "An empirical potential for hydrogen bond energies determination of the orientation of anthracene molecules in the unit cell by means of a refractivity method: some ab initio calculations involving acetonitrile exchange reaction." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/76509.
Повний текст джерелаPh. D.
Rose, Philipp [Verfasser], and M. [Akademischer Betreuer] Wietschel. "Modeling a potential hydrogen refueling station network for fuel cell heavy-duty vehicles in Germany in 2050 / Philipp Rose ; Betreuer: M. Wietschel." Karlsruhe : KIT-Bibliothek, 2020. http://d-nb.info/121100628X/34.
Повний текст джерелаKhalil, R. M. A. "Ab initio studies of the structural, dynamical and thermodynamical properties of graphitic and hydrogenated graphitic materials and their potential for hydrogen storage." Thesis, University of Salford, 2014. http://usir.salford.ac.uk/32059/.
Повний текст джерелаЦейтлин, Мусий Абрамович, та Валентина Федоровна Райко. "Математическое моделирование равновесного состава системы BaS–Ba(HS)₂–H₂S–H₂O". Thesis, Національний технічний університет України "Київський політехнічний інститут імені Ігоря Сікорського", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/41241.
Повний текст джерелаA mathematical model describing the equilibrium composition of the BaS–Ba(HS)₂–H₂S–H₂О system is developed. Model allows, in particular, to calculate the pH of the solution, and was used to calculate the driving force for desorption of hydrogen sulfide in the process of obtaining barium carbonate.
Horbatenko, Yevhen. "Structure and hydrogen dynamic behavior in proton sponge cations and organometallic complexes." Doctoral thesis, Universitat de Girona, 2013. http://hdl.handle.net/10803/128511.
Повний текст джерелаAquesta tesi es centra en l'estudi del comportament dinàmic d'hidrogen en una sèrie de cations d'esponges de protó, així com en bis(silil)hidrur complexos organometàl•lics. Per entendre el comportament dinàmic, una nova eina com l'equació de Schrödinger vibracional tridimensional s'ha derivat i resolt. S'han trobat tres patrons diferents pel moviment vibracional d'hidrogen. S'ha proposat la classificació d'esponges de protó i bis(silil)hidrur complexos amb el comportament d'hidrogen localitzat i deslocalitzat. Per als complexos organometàl·lics s'ha estudiat la influència del moviment vibracional d'hidrogen en J(Si–H) constants d'acoblament de espín-espín. Una altra part d'aquesta tesi presenta un estudi de [Cp*Co(SiR3)2(H)2] complexos de cobalt i els seus anàlegs d'iridi per detectar possibles interaccions Si···H. Basat en geometries moleculars, en els índexs d'enllaç de Wiberg i constants d'acoblament d'espín-espín J(Si-H), s'han detectat almenys dues interaccions residuals Si···H en els complexos de cobalt, mentre que hi ha interaccions rudimentàries Si···H en el cas dels complexos d'iridi
Topriska, Evangelia Vasiliki. "Experimental and computational study of a solar powered hydrogen production system for domestic cooking applications in developing economies." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/12824.
Повний текст джерелаGrant, Paul Allan Anthony. "A study of the neurotoxic effects of hydrogen peroxide and of the potential neuroprotective effects of carbachol in SK-N-SH human neuroblastoma cells." Thesis, King's College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322307.
Повний текст джерелаLIRA, Renato Pereira de. "Qualidade pós-colheita da abóbora brasileirinha (curcubita moshata) em diferentes épocas de colheita e tempos de armazenamento." Universidade Federal de Campina Grande, 2017. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/757.
Повний текст джерелаMade available in DSpace on 2018-05-21T14:11:42Z (GMT). No. of bitstreams: 1 RENATO PEREIRA DE LIRA - DISSERTAÇÃO - PPGHT 2017.pdf: 987783 bytes, checksum: 8391dfae9bf28758906732802082b7e7 (MD5) Previous issue date: 2017-08-24
A abóbora ‘Brasileirinha’ é uma cultivar que produz frutos bicolores (verde e amarelo) com excelente potencial nutricional. No entanto, a época de colheita e o tempo de armazenamento podem ser considerados fatores que interferem diretamente na qualidade do fruto. Assim, objetivou-se avaliar a qualidade pós–colheita da abóbora brasileirinha em diferentes épocas de colheita e tempo de armazenamento. Os frutos foram colhidos em uma área de cultivo, localizado no município de Teixeira – PB a 103 km de Pombal – PB. A pesquisa foi realizada entre março e maio de 2016, no Laboratório de Química, Bioquímica e Análises de Alimentos do Centro de Ciências e Tecnologia Agroalimentar da Universidade Federal de Campina Grande, Pombal - PB. Utilizou-se o delineamento inteiramente casualizado, em esquema fatorial 3 x 6, três épocas de colheita da abóbora (70, 90 e 110 dias após o plantio) e seis tempos de armazenamento (0, 7, 14, 21, 28 e 35 dias), contendo 5 repetições, com 1 fruto por repetição. As características físicas avaliadas foram: perda de massa fresca, comprimento longitudinal, diâmetros superior e inferior, cavidade interna, espessura da polpa, espessura da polpa do pescoço e firmeza. As características químicas avaliadas foram: potencial hidrogeniônico (pH), vitamina C, sólidos solúveis (SS), acidez titulável (AT), razão (SS/AT), carotenóides total, compostos fenólicos, flavonoides, antocianinas, açucares solúveis totais e açucares redutores. As características físicas avaliadas, não apresentaram diferença significativa nas três épocas de colheita, com exceção da firmeza que variou de 136 a 158 N. Os frutos oriundos da terceira época de colheita aos (110 dias) foram os que apresentaram os maiores teores de sólidos solúveis, vitmina C e carotenóides durante os 35 dias de armazenamento. A razão SS/AT foi maior na primeira época de colheita aos (70 dias). Os frutos oriundos da terceira época de colheita aos (110 dias) foram os que resultaram melhor qualidade para as características físicas e químicas estudadas, sendo recomendado a melhor época de colheita para o consumo da abóbora brasileirinha.
A 'Brasileirinha' pumpkin is a cultivar that produces bicolour fruits (green and yellow) with excellent nutritional potential. However, a harvesting time and storage time can be considered factors that interfere in the quality of the fruit. The objective of this study was to evaluate a post-harvest quality of the Brazilian pumpkin at different harvesting times and storage time. The fruits were harvested in a growing area, located in the municipality of Teixeira - PB, 103 km from Pombal - PB. The research was carried out between March and May of 2016, not Laboratory of Chemistry, Biochemistry and Food Analysis of the Center of Sciences and Technology Agrifood of the Federal University of Campina Grande, Pombal - PB. A completely randomized design was used in a 3 x 6 factorial design, three pumpkin harvest times (70, 90 and 110 days after the plan) and six storage times (0, 7, 14, 21, 28 and 35 days ), containing 5 replicates, with 1 fruit per replicate. The physical characteristics evaluated were: loss of fresh mass, longitudinal length, upper and lower diameters, internal cavity, pulp thickness, neck pulp thickness and firmness. The chemical characteristics evaluated were: hydrogenation potential (pH), vitamin C, soluble solids (SS), titratable acidity (AT), ratio (SS / AT), total carotenoids, phenolic compounds, flavonoids, anthocyanins, total soluble sugars and sugars. . The physical characteristics evaluated did not present the difference in the three harvest periods, with the exception of the company that ranged from 136 to 158 N. The fruits from the third harvest season at (110 days) were those that presented the highest solids soluble Vitmina C and carotenoids during the 35 days of storage. The SS / AT ratio was higher in the first harvest season at (70 days). The fruits from the third harvest season at (110 days) were the ones that resulted in better quality for the physical and chemical characteristics studied, being recommended the best harvest season for the Brazilian pumpkin consumption.
Haurais, Florian. "Evaluate the contribution of the fuel cladding oxidation process on the hydrogen production from the reflooding during a potential severe accident in a nuclear reactor." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS375/document.
Повний текст джерелаIn nuclear power plants, a severe accident is a very unlikely sequence of events during which components of the reactor core get significantly damaged, through chemical interactions and/or melting, because of very high temperatures. This may potentially lead to radiotoxic releases in the containment building and to air ingress in the reactor core. In that context, this thesis work led at EDF R&D aimed at modeling the deterioration of the nuclear fuel cladding, made of zirconium alloys, in accidental conditions: high temperature and either pure steam or air-steam mixture. The final objective was to improve the simulation by the MAAP code of the cladding oxidation and of the hydrogen production, in particular during a core reflooding with water. Due to the progressive thickening of a dense and protective ZrO2 layer, the oxidation kinetics of Zr in steam at high temperatures is generally (sub-)parabolic. However, at certain temperatures, this oxide layer may crack, becoming porous and not protective anymore. By this “breakaway” process, the oxidation kinetics becomes rather linear. Additionally, the temperature increase can lead core materials to melt and to relocate down to the vessel lower head whose failure may induce air ingress into the reactor core. In this event, oxygen and nitrogen both react with the pre-oxidized claddings, successively through oxidation of Zr (thickening the ZrO2 layer), nitriding of Zr (forming ZrN particles) and oxidation of ZrN (creating oxide and releasing nitrogen). These self-sustained reactions enhance the cracking of the cladding and of its ZrO2 layer, inducing a rise of its open porosity.In order to quantify this cladding porosity, an innovative two-step experimental protocol was defined and applied: it consisted in submitting ZIRLO® cladding samples first to various accidental conditions during several time periods and then to measurements of the open porosity through porosimetry by mercury intrusion. The tested corrosion conditions included numerous temperatures ranging from 1100 up to 1500 K as well as both pure steam and a 50-50 mol% air-steam mixture. For the ZIRLO® samples oxidized in pure steam, except at 1200 and 1250 K, the “breakaway” kinetic transitions do not occur and the open porosity remains negligible along the oxidation process. However, for all other samples, corroded in air-steam or oxidized in pure steam at 1200 or 1250 K, “breakaway” transitions are observed and the porosimetry results show that the open porosity increases along the corrosion process, proportionally to the mass gain. Moreover, it was evidenced that the pore size distribution of ZIRLO® samples significantly extends during corrosion, especially after “breakaway” transitions. Indeed, the detected pore sizes ranged from 60 μm down to around: 2 μm before the transition, 50 nm just after and 2 nm longer after. Finally, a two-step numerical model was developed in the MAAP code to improve its simulation of the cladding oxidation. First, thanks to the proportionality between open porosity and mass gain of cladding samples, porosity correlations were implemented for each tested corrosion condition. Second, the calculated porosity values are used to proportionally enhance the cladding oxidation rate. This improved model thus simulates not only chemical reactions of Zr-based claddings (oxidation and nitriding) but also their mechanical degradation and its impact on their oxidation rate. It was validated by simulating QUENCH tests (-06, -08, -10 and -16), conducted at KIT to study the behavior of claddings in accidental conditions with a final reflooding. These simulations show a better cladding thermal behavior and a hydrogen production significantly higher and so closer to experimental values, in particular during the reflooding
Guimarães, João de Jesus. "Comportamento agronômico do lúpulo (Humulus lupulus L.) em cultivo protegido submetido a irrigações com diferentes faixas de pH da água na região de Botucatu-SP /." Botucatu, 2020. http://hdl.handle.net/11449/192238.
Повний текст джерелаResumo: O cultivo de lúpulo (Humulus Lupulus L) exige um adequado fornecimento de água, principalmente na fase de desenvolvimento, o qual envolve a formação e crescimento dos ramos laterais, florescimento, formação das inflorescências e maturação dos cones. Sabendo da importância do fornecimento de água na fase de desenvolvimento, a irrigação passou a ser utilizada nas áreas de cultivo desde o século XIX. No contexto da irrigação, a qualidade da água é um fator importante e que, quando não se dá a devida atenção, pode causar efeitos deletérios no sistema de irrigação, solo e na planta. O potencial hidrogeniônico (pH) é um dos parâmetros que caracteriza a qualidade de água para irrigação podendo influenciar na microbiologia do solo e no processo de intercâmbio de cátions (solo para a solução e vice-versa). Em virtude da importância da irrigação e dos poucos estudos relacionados ao pH da água da irrigação da cultura do lúpulo, este trabalho teve como objetivo avaliar o efeito da irrigação com diferentes faixas de pH da água sob o desenvolvimento agronômico do lúpulo, variedade Cascade, cultivado em ambiente protegido. A pesquisa foi conduzida em casa de vegetação no Departamento de Bioprocessos e Biotecnologia – DBB da Faculdade de Ciências Agronômicas – FCA/UNESP, Campus de Botucatu. O delineamento estatístico utilizado foi o inteiramente casualizados (DIC) com três tratamentos e dez repetições. Os tratamentos foram constituídos por três faixas de pH da água, sendo: T1 – pH 6 a 6,5, T... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Hop cultivation (Humulus Lupulus L) requires a adequate supply of water, especially at the developmental stage, or as involved in lateral branch formation and growth, flowering, inflorescence formation and cone maturation. Knowing the importance of water supply in the development phase, irrigation has been used in cultivated areas since the 19th century. In the context of irrigation, water quality for irrigation is an important factor which, when not given due attention, can have deleterious effects on the irrigation system, soil and the plant. The hydrogen potential (pH) of water is one of the parameters that characterizes the quality of water for irrigation and can influence soil microbiology and the cation exchange process (soil for solution and vice versa). Due to the importance of irrigation and the few studies related to the water pH of the irrigation of the hop culture, this work had as objective evaluate the effect of irrigation with different water pH ranges on the agronomic development of hops, Cascade variety cultivated in protected environment. The research was conducted in a greenhouse at the Department of Bioprocesses and Biotechnology – DBB of the Faculty of Agronomic Sciences - FCA/UNESP, Botucatu Campus. The statistical design used was the completely randomized design (CRD) with three treatments and ten replications. The treatments consisted of three water pH ranges: T1 - pH 6 to 6.5, T2 - pH 6.5 to 7 and T3 - 7 to 7.5. To obtain the treatments, 0,1 mol L-1 s... (Complete abstract click electronic access below)
Mestre
Polischuk, Vladimir. "Etude et réalisation de structure à base de silicium poreux en vue de la détection de gaz." Ecully, Ecole centrale de Lyon, 1999. http://www.theses.fr/1999ECDL0016.
Повний текст джерелаPinto, Marcelo Mendes. ""Influência do pH de armazenamento no crescimento subcrítico de trincas de porcelanas odontológicas com diferentes microestruturas"." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/23/23140/tde-28082006-200019/.
Повний текст джерелаThe objective of the study was to determine the effect of the pH of the storage medium (pH 3,5; 7,0 e 10,0) on the fatigue parameters (n and ? f0) of two dental porcelains with different microstructures (with and without leucite). The hypothesis tested was that the pH affects the fatigue parameters of both materials. The dental porcelains tested were: 1) Ultropaline Dentin (UD), JenDental/Ucraine; 2) Veneer Material 7 (VM7), Vita/Germany. UD contains leucite and VM7 is only vitreous. Disc specimens were produced with both materials following manufacturers firing cycles. The specimens were stored in water solutions with different pHs (3,5; 7,0 e 10,0) for 10 days and after that the fatigue parameters were obtained by means of the dynamic fatigue test. Hardness and fracture toughness were determined by means of the indentation fracture technique. Microstructural analysis of the materials was also carried out. The effect of the pH in the fatigue parameters was different for the two materials tested. The results showed that, for VM7, the n value did not vary as a function of the pH. For porcelain UD, the n value was lower when the specimens where stored in pH 3,5. The parameter ? f0 was also affected by the pH. For both materials, the storage in basic pH resulted in a decrease in the ? f0 value. The hardness of both materials decreased with the increase in the pH of the storage media, and fracture toughness was not affect by the pH. Based on the results, it was possible to conclude that the effect of the pH (of the storage media) on the fatigue parameters of the dental porcelains studied varied according to the porcelains microstructure.
Nylén, Linda. "Influence of the electrolyte on the electrode reactions in the chlorate process." Doctoral thesis, KTH, Tillämpad elektrokemi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4681.
Повний текст джерелаFramställning av klorat är mycket energiintensiv och kräver stora mängder elenergi. Stigande elpriser, som dessutom ofta varierar under dygnet eller säsongsvis, gör att man vill reducera onödiga förluster samt ibland försöka anpassa produktionen så att man när elpriset är högt minskar den, för att sedan öka produktionen igen då elpriset sjunker. Denna flexibla drift kräver ny kunskap om hur elektroderna beter sig i ett större strömintervall än vad som tidigare varit av intresse. Målet med detta arbete var att, med fokus på elektrolytens betydelse, identifiera möjliga förbättringar för kloratprocessen och därmed minska energiförbrukningen. Studierna har i huvudsak varit experimentella men även matematisk modellering har använts. Ett brett strömintervall har undersökts för att bättre förstå fenomenen och för att även kunna använda resultaten då höga elpriser gör att man vill köra processen vid lägre laster än normalt. För att driften av anoden ska vara så energieffektiv som möjligt bör anodpotentialen inte överskrida den kritiska potentialen (Ecr), där den anodiska polarisationskurvan får en högre lutning (troligtvis pga Ru(VIII)-bildning) och bireaktionen syrgasutveckling ökar. I detta arbete har påverkan av olika elektrolytparametrar på Ecr undersökts. Det visade sig att en ökad kloridkoncentration och ökad temperatur sänkte Ecr. Trots att detta borde göra att Ecr lättare överskrids, blev inte detta fallet eftersom kloridoxidationen samtidigt gynnades. Slutsatsen blir därför att elektrolytparametrarna bör optimeras så att lägsta möjliga anodpotential uppnås, vilket då även gör att strömtätheten kan ökas utan att Ecr överskrids. Slutsatsen är vidare att polarisationskurvans högre lutning vid Ecr kan ha att göra med att rutenium oxiderat till rutenium(VIII) har lägre aktivitet för kloridoxidation. Vid full last visade sig katodens potential vara relativt oberoende av elektrolytsammansättningen trots att denna varierades kraftigt. Katodens sammansättning verkar vara viktigare att ta hänsyn till än elektrolytens för kunna åstadkomma en större energibesparing. Ett alternativ till att öka katodens aktivitet skulle vara att in-situ belägga elektrodytan med en katalytisk film. Försök gjordes att sätta till Y(III) till kloridelektrolyt för att under vätgasutveckling fälla ut en yttriumhydroxidfilm på den alkaliska katodytan. Yttriumhydroxidfilmen aktiverade vattenreduktion (vätgasutveckling) och inhiberade hypokloritreduktion, protonreduktion och nitratreduktion. De inhiberande egenskaperna är viktiga för att förhindra bireaktioner, vilka idag hindras av att Cr(VI) i elektrolyten reduceras på katoden och bildar en hindrande kromhydroxidfilm. Försöken med Y(III) visar att det finns goda möjligheter att hitta alternativ till det miljöfarliga Cr(VI). Kromattillsatsen i kloratelektrolyt ger förutom ett högt katodiskt strömutbyte även en buffrande effekt till elektrolyten. Effekten av buffert har undersökts för en av de anodiska bireaktionerna, syrgasutveckling ur vatten, samt för vätgasutvecklingen på katoden. Dessa system har modellerats för att bättre förstå samspelet mellan buffert, elektrodreaktioner och materietransport och resultaten har verifierats experimentellt. Kromatbufferten ökade gränsströmmen för katodisk H+-reduktion betydligt och katodöverpotentialen sjönk kraftigt vid lägre strömmar än gränsströmmen. Detta kan vara ett problem om överpotentialen sjunker så lågt att elektroden inte är katodiskt skyddad. För syrgasutvecklingen ökade närvaron av kromatbuffert gränsströmmen för syrgasutveckling ur OH-. Modellering av dessa system visar att de homogena reaktioner som var kopplade till elektrodreaktionerna inte var i jämvikt vid elektrodytan. Vidare visade det sig vara mycket viktigt med en bra upplösning av gränsskiktet vid elektrodytan, då den buffring som är viktig för elektrodreaktionerna sker i ett mycket tunt reaktionsskikt (nanometertjockt).
QC 20100901
Abdel, Latif Marwa K. "Electrochemical oxidation of aliphatic carboxylates: Kinetics, thermodynamics, and evidence for a shift from a concerted to a stepwise mechanism in the presence of water." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/82522.
Повний текст джерелаPh. D.
Bataillon, Christian. "Application de l'analyse spectrale du bruit electrochimique a l'etude de la corrosion par piqures des alliages d'aluminium." Paris 6, 1987. http://www.theses.fr/1987PA066251.
Повний текст джерелаPEREIRA, Francinaldo de Freitas. "Desenvolvimento e avaliação de um sistema de aquecimento utilizando hidrogênio eletrolítico como combustível." Universidade Federal de Campina Grande, 2005. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/2009.
Повний текст джерелаMade available in DSpace on 2018-10-18T14:27:42Z (GMT). No. of bitstreams: 1 FRANCINALDO DE FREITAS PEREIRA - TESE PPGEP 2005..pdf: 5181579 bytes, checksum: 4b0502fc646549fa86f1d070395e206c (MD5) Previous issue date: 2005-08-26
Capes
O objetivo deste trabalho é estudar o desempenho de um forno tipo mufla adaptado para utilizar hidrogénio eletrolítico como combustível. O sistema de aquecimento poderá ser aplicado em fornos de produção de tijolos, telhas, materiais cerâmicos, e produtos derivados do trigo. Neste sentido o hidrogénio eletrolítico substituiria os combustíveis de origem orgânica, que são os grandes vetores da poluição atmosférica, o hidrogénio poderá ser produzido usando-se energias renováveis como painéis fotovoltaicos e/ou turbinas eólicas. O hidrogénio foi produzido a partir da eletrolise da água em um reator bipolar usando hidróxido de potássio como eletrólito. O consumo de energia e a produção de hidrogénio foram estimados para diferentes níveis temperaturas de 300°C, 900°C e, 1100°C.
The objective of this work is the study of an oven adapted to use electrolytic hydrogen as fuel. The possible applications are the cooking of clay used in the production of ceramic materiais, bricks and tiles; as well as the production of derived products of the wheat. The electrolytic hydrogen, used as a fuel in replacement of carbonaceous fuels which contribute to the atmospheric pollution, can be produced using renewable energies like photovoltaic solar paneis and/or aeolian turbine power generators. The hydrogen production is done by electrolysis of water which occurs in a bipolar reactor using potassium hydroxide as electrolyte. The energy consumption and the hydrogen production are calculated for different temperatures of 300°C, 900°C and 1100°C range. They are respectively, 0,9 kWh and 0,131 m3, 2,1 kWh and 0,311 m3 and 3,2 kWh and 0,498 m3.