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Parente, Alexis. "Dualités fonctionnelles de GASP-1 et GASP-2, deux protéines multi-domaines antagonistes de la myostatine." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0028.
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GASP-1 et GASP-2 sont deux protéines très proches structuralement caractérisées par plusieurs modules inhibiteurs de protéases et identifiés comme des inhibiteurs de plusieurs membres de la famille TGF-ß tel que la myostatine ou GDF-11, respectivement régulateurs négatifs de la myogenèse et de l’ostéogénèse. Malgré l’organisation structurale commune des protéines GASPs, leurs profils d’expression différents laissent supposer des rôles physiologiques distincts. C’est pourquoi, nous avons généré des modèles souris Tg(Gasp-1) et Tg(Gasp-2) surexprimant Gasp-1 ou Gasp-2 afin de mieux appréhender les fonctions de ces protéines. Des analyses fonctionnelles, réalisées in vitro et in vivo dans les contextes musculaire, squelettique et anti-protéasique, nous ont permis de mettre en lumière une dualité fonctionnelle entre GASP-1 et GASP-2 dans ces différents contextes. Les deux lignées Tg(Gasp-1) et Tg(Gasp-2) présentent une augmentation de la masse musculaire due à une hypertrophie sans hyperplasie des myofibres. Cependant, les souris Tg(Gasp-1) présentent une dérégulation globale de l’homéostasie du glucose et des défauts métaboliques en vieillissant, phénotype non retrouvé chez les souris Tg(Gasp-2). Ces résultats nous a permis de proposer la protéine GASP-2 comme étant un meilleur candidat thérapeutique dans le cas de maladies musculaires. Dans le contexte squelettique, seule la surexpression de Gasp-2 entraine un phénotype osseux. L’ensemble de nos résultats permet de mettre en évidence un réseau de régulation de l’expression génique des membres de la famille TGF-ß et de leurs inhibiteurs dans le muscle<br>GASP-1 and GASP-2 are two closely related proteins structurally characterized by several protease inhibitor modules and identified as inhibitors of several members of the TGF-ß family such as myostatin or GDF-11, negative regulators of myogenesis and osteogenesis, respectively. Despite the common structural organization of GASPs proteins, their different expression profiles suggest distinct physiological roles. We generated Tg(Gasp-1) and Tg(Gasp-2) mouse models overexpressing Gasp-1 or Gasp-2 in order to better understand the functions of these proteins. Functional analyses, carried out in vitro and in vivo in muscular, skeletal and anti-proteasic context, allowed us to highlight a functional duality between GASP-1 and GASP-2 in the different contexts. Both lines Tg(Gasp-1) and Tg(Gasp-2) exhibit an increase in muscle mass due to myofiber hypertrophy without hyperplasia. However, Tg(Gasp-1) mice have an overall deregulation of glucose homeostasis and metabolic defects with age, a phenotype not found in Tg(Gasp-2) mice. These results allowed us to propose the GASP-2 protein as a better therapeutic candidate for muscle diseases. In the skeletal context, only the Gasp-2 overexpression leads to a bone phenotype. Altogether, our findings highlighted a gene expression regulatory network of TGF-ß members and their inhibitors in muscle
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Perie, Luce. "La myostatine et ses partenaires GASP-1 et GASP-2 : implications dans le développement musculaire et le métabolisme du glucose." Thesis, Limoges, 2015. http://www.theses.fr/2015LIMO0072/document.
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Le muscle squelettique est un tissu hétérogène et dynamique jouant un rôle important dans la mobilité et le métabolisme d’un organisme. C’est un organe actif qui sécrète de nombreuses cytokines participant au « crosstalk » entre tous les tissus impliqués dans ce métabolisme. Parmi ces myokines, la myostatine agit à la fois comme un régulateur négatif du développement musculaire et un médiateur dans l’homéostasie du glucose. En effet, les souris déficientes pour le gène de la myostatine (Mstn-/-) présentent une augmentation de leur masse musculaire associée à une hyperplasie et une hypertrophie des myofibres. Elles présentent également une diminution de leur masse adipeuse. L’expression de la myostatine est finement régulée par des inhibiteurs comme la follistatine, FSTL3 ou les protéines GASP-1 et GASP-2. Si de nombreuses études ont déjà été réalisées sur les autres inhibiteurs, les protéines GASPs sont à l’heure actuelle encore peu étudiées. Le modèle murin surexprimant Gasp-1 (Tg(Gasp-1) généré dans le laboratoire présente un phénotype hypermusclé associé à une hypertrophie mais sans hyperplasie et ne présentent pas de diminution de leur masse adipeuse. Afin de mieux comprendre les conséquences fonctionnelles de la surexpression de Gasp-1, nous avons analysé des cellules musculaires dérivées de cellules satellites de souris Tg(Gasp-1). Cette étude a révélé une dérégulation de l’expression de plusieurs gènes dont une surexpression de la myostatine qui pourrait expliquer l’absence d’hyperplasie. Nous avons voulu également expliquer l’absence de variation de masse adipeuse dans les souris Tg(Gasp-1) en réalisant des analyses métaboliques sur des souris jeunes et âgées. Ces travaux ont révélé une dérégulation globale de l’homéostasie du glucose dans les souris Tg(Gasp-1) associé à une dérégulation du sécrétome musculaire. Enfin nous avons voulu appréhender le rôle de GASP-2 dans le contexte musculaire<br>Skeletal muscle is a heterogeneous and dynamic tissue which plays an important role in mobility and metabolism of organisms. It is an active organ that secretes numerous cytokines involved in "crosstalk" between all tissues implicated in metabolism. Among these myokines, myostatin acts both as a negative regulator of muscle development and a mediator in glucose homeostasis. Indeed, mice deficient for the myostatin gene (Mstn-/-) have an increase of muscle mass associated with hyperplasia and hypertrophy of myofibers. Mstn-/- mice also exhibit a decrease of fat mass. Expression of myostatin is tightly regulated by inhibitors such follistatin, FSTL-3 or GASP-1 and GASP-2 proteins. While many studies have already been performed on the other inhibitors, GASPs proteins are still poorly studied. The mouse model overexpressing Gasp-1 (Tg (Gasp-1)) generated in our lab presents a hypermuscular phenotype associated with hypertrophy without hyperplasia and exhibit no decrease in fat mass. To better understand the functional consequences of Gasp-1 overexpression, we analyzed muscle cells derived from Tg(Gasp-1) satellite cells This study revealed a deregulation of the expression of several genes with an upregulation of myostatin which could explain the absence of hyperplasia in the Tg(Gasp-1) mice. We then want to explain the absence of fat mass changes by performing metabolic assays in young and aged mice. These studies have revealed an overall dysregulation of glucose homeostasis and deregulation of muscle secretome in Tg(Gasp-1) mice. Finally we wanted to capture the role of GASP-2 in a muscular context
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Al, Mansi Montasir. "In vitro study of the structure / function relationship of the proteins GASP-1 and GASP-2 : Involvement of the second Kunitz domain in the functional duality of the GASP proteins." Thesis, Limoges, 2018. http://www.theses.fr/2018LIMO0064/document.
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Les muscles squelettiques, responsables des mouvements volontaires tels que la locomotion ou le maintien de la posture, représentent environ 40% de la masse corporelle.Cette masse musculaire est maintenue par plusieurs voies de signalisation qui régulent entre autres l’équilibre entre la synthèse et la dégradation des protéines myofibrillaires. En ciblant la voie de signalisation Akt/mTOR, la myostatine est un régulateur négatif de la myogenèse. Elle inhibe la différentiation myogénique et le renouvellement cellulaire. Parmi les différents facteurs moléculaires extracellulaires qui régulent la myostatine, les protéines GASP (Growth and differentiation factor Associated Serum Protein) ont été décrites comme des antagonistes de son activité. L’Unité de Génétique Animale a développé plusieurs stratégies qui permettent d’appréhender les mécanismes moléculaires qui régissent le(s) rôle(s) des protéines GASP au cours du développement musculaire. Ainsi, la création de la lignée murine appelée surGasp-1-20 a permis de montrer que la surexpression de Gasp-1 entraîne un phénotype hypermusclé associé à une hypertrophie des myofibrilles. Une analyse de l’expression génique dans des myoblastes dérivés des cellules satellites montre une surexpression de la myostatine corrélant avec une absence d’hyperplasie chez les souris surGasp-1-20. Des études similaires actuellement en cours pour la protéine GASP-2 devraient permettre de préciser son rôle dans le contexte musculaire. Les protéines GASP sont également définies comme des inhibiteurs composés hétérotypiques caractérisés par plusieurs domaines inhibiteurs pouvant moduler l’activité de différentes protéases. Parmi ces différents domaines,le second domaine Kunitz de GASP-2 a été précédemment décrit comme pouvant inhiber la trypsine. Dans ce travail, nous avons pu montrer que les deux protéines entières conservent cette capacité d’inhibition. Nos résultats indiquent cependant que GASP-1 et GASP-2 présentent une différence de spécificité due à la composition du second domaine Kunitz et non à l’environnement moléculaire présent dans chacune des protéines. Enfin, nous proposons un modèle structural du second domaine Kunitz impliqué dans la dualité fonctionnelle dans l'inhibition anti-trypsine de GASP-1 et GASP-2<br>Skeletal muscles, responsible for voluntary movements such as locomotion or posture maintenance, represent about 40% of body mass. This muscle mass is maintened by several signaling pathways that regulate , among other things, the balance between synthesis and degradation of myofibrillar proteins. By targeting the Akt/mTOR pathway, myostatin is anegative regulator of myogenesis. It inhibits myogenic differentiation and cell turnover. Among the various endogenous molecular factors that regulate myostatin, proteins GASP (Growth and differentiation factor Associated Serum Protein) have been described as antagonists of its activity. The Animal Genetics Unit has developed several strategies to understand themolecular mechanisms that govern the role (s) of GASP proteins during muscle development.Thus, the creation of the transgenic mouse line named surGasp-1-20 has shown that overexpression of Gasp-1 results in a hypermuscular phenotype associated with myofibril hypertrophy. An analysis of gene expression in myoblasts derived from satellite cells showed overexpression of myostatin correlating with an absence of hyperplasia in Gasp-1-20 mice.Similar studies currently underway for the protein GASP-2 should clarify its role in the muscular context. Proteins GASP are also defined as compound heterotypic inhibitors characterized by several inhibitory domains that can modulate the activity of different proteases. Among these different modules, the second Kunitz domain of GASP-2 was previously been described asable to inhibit trypsin. In this work, we have shown that the two whole proteins conserve this capacity of inhibition. However, our results indicate that GASP-1 and GASP-2 exhibit a difference in specificity due to the composition of the second Kunitz domain and not to the molecular environment present in each of the proteins. Finally, by modeling, we propose a structural model of the second Kunitz domain of GASP-1 and GASP-2 implicated in the antitrypsin inhibition specificity
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Zheng, Xiaoyi. "GASP-1, a New Tumor Biomarker, Contributes to Tumorigenesis in Breast Cancer." Diss., Temple University Libraries, 2013. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/214816.
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Biology<br>Ph.D.<br>Breast cancer is the second leading cause of death in United States. Using 2D-HPLE, a novel separation technology, G-protein coupled receptor-associated sorting protein 1(GASP-1) was identified in sera of patients with early stage cancer, while it could not be detected in sera from healthy individuals. This was the first indication that GASP-1 was positively correlated with breast cancer. However, the function of GASP-1 in breast cancer was unknown. In this study, I verified the 2D-HPLE results by quantifying the expression level of GASP-1 in sera and tissue specimens of cancer patients using specific antibodies against GASP-1. A GASP-1 specific ELISA was developed and used to quantify GASP-1 levels in cancer patient sera. Immunohistochemistry was performed to verify and localize GASP-1 expression in tumor. I also characterized the tumorigenic potential of GASP-1 andidentified the signaling pathways mediated by GASP-1 in breast cancer cells in vitro.GASP-1 expression levelsin MDA-MB-231 cells were modified by transfecting cells with anti-GASP-1 shRNA and over-expression plasmids. Stable cell lines were prepared and their tumorigenic potential was evaluated using cell proliferation, migration, and colony formation assays. These cells were analyzed for markers used to identify epithelial to mesenchymal transition (EMT) using RT-PCR and western blot. They were also analyzed for NFkappaB activity, src phosphorylation, and GPR30 expression. The results showed that GASP-1 was over-expressed in sera and tissue specimens of breast cancer patients and other cancer types including brain, lung, liver and pancreatic cancer and that it correlated with early stage disease. GASP-1 positively regulated migration, and is required for cell proliferation and colony formation. GASP-1 is also necessary for the expression of EMT marker slug, increases NFkappaB activity and GPR30 expression level, while decreases the inhibitory phospho-src Tyr 530. I conclude that GASP-1 is a nearly marker for multiple cancer types. GASP-1 promotes tumorigenesis in breast cancer, possibly through multiple cancer related signaling pathways. These findings may contribute to our understanding of the mechanism of breast cancer tumorigenesis and identify new biomarkers that can be used for diagnosis and therapy of cancer.<br>Temple University--Theses
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Brun, Caroline. "Etude des conséquences fonctionnelles de l’inhibition de la myostatine par GASP-1 au cours du développement musculaire." Limoges, 2013. http://aurore.unilim.fr/theses/nxfile/default/c8d0d105-e5c8-4dc8-b62e-1d305ee479eb/blobholder:0/2013LIMO4031.pdf.
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Le muscle squelettique est un organe possédant une grande plasticité et dont la masse est maintenue par différentes voies de signalisation régulant le turnover protéique et cellulaire. Parmi elles, la voie de signalisation de la myostatine agit comme un régulateur négatif de la croissance musculaire. Elle nécessite une régulation complexe, majoritairement exercée par ses inhibiteurs tels que la follistatine, le propeptide et GASP-1 (Growth and differentiation factor-associated serum protein-1). Bien que de nombreuses analyses aient été menées sur l’inhibition de la myostatine induite par son propeptide ou par la follistatine, les études concernant la protéine GASP-1 se sont jusqu’à présent principalement concentrées sur la caractérisation fonctionnelle de ses domaines. Nous avons généré des lignées murines transgéniques surexprimant Gasp-1, appelées surGasp1. Deux de ces lignées, surGasp1-20 et surGasp1-06, ont été sélectionnées pour leurs niveaux élevés d’expression de Gasp-1 dans le muscle et le cerveau. Ces lignées présentent une augmentation de la masse musculaire due à une hypertrophie des myofibres sans hyperplasie. Pour comprendre les mécanismes moléculaires régulant la masse musculaire des souris surGasp1, nous avons analysé les myoblastes dérivés des cellules satellites des souris sauvages, surGasp1-20 (S20) et Mstn -/-. L’analyse de leurs expressions géniques a révélé une augmentation de la myostatine dans les myoblastes S20. Nous avons également mis en évidence une augmentation de la phosphorylation de ERK1/2 et une diminution de Pax7 dans ces cellules par rapport aux cellules Mstn -/-. Nous avons proposé que la dérégulation de Pax7 dans les myoblastes S20 pourrait être induite par la surexpression de la myostatine et corrèlerait avec l’absence d’hyperplasie chez les souris surGasp1. En parallèle, nous avons montré que les myoblastes S20 présentent une augmentation de la signalisation pro-hypertrophique Akt/mTORC/p70S6K, favorisant la différenciation des myotubes et l’augmentation de leur taille, confirmant que la surexpression de Gasp-1 conduit à une hypertrophie des myofibres<br>Skeletal muscle is a plastic organ that is maintained by multiple factors regulating cell and protein turnover. Among them, myostatin functions as a negative regulator of muscle growth. The regulation of myostatin is mostly carried out by its physiological inhibitors such as its propeptide, follistatin or GASP-1 (Growth and differentiation factor-associated serum protein-1). Although many analyzes were conducted on the inhibition of myostatin induced by its propeptide or follistatin, studies on GASP-1 mainly focused on the functional characterization of its domains. To highlight the Gasp-1 function in vivo, transgenic mouse lines that overexpress Gasp-1 were generated and called surGasp1 mice. Two lines, namely surGasp1-20 and surGasp1-06, were selected for their highest Gasp-1 overexpression in muscle and brain. These mouse lines showed an increased muscle mass due to myofibre hypertrophy rather than hyperplasia. To investigate the molecular mechanisms regulating muscle mass in surGasp1 mice, we studied the myoblasts derived from wild-type, surGasp1-20 (S20) and Mstn -/- satellite cells. Expression array analysis revealed an up-regulation of myostatin expression in S20 myoblasts. We also found an increased ERK1/2 phosphorylation and a decrease of Pax7 in S20 cells compared to the Mstn -/-. We propose that the deregulation of Pax7 in overexpressing Gasp-1 myoblasts is related with an upregulation of myostatin and it could be responsible for the absence of hyperplasia in surGasp1-20 mice. In addition, we showed that S20 myoblasts increase the pro-hypertrophic Akt/mTORC/p70S6K signaling, enhancing myoblast differentiation and myotube size. This confirms that Gasp-1 overexpression leads to myofibre hypertrophy. The P3HT were established. The characterization of layers by advanced techniques, by using an extension of the near-field microscopy called Resiscope, allowed to put emphasize on the evolution of the morphology of P3HT: PCBM heterojunction in bulk and layers in bilayers structures of types P3HT: C60. The use of the image representing the deflection lever enabled the coupling of the layers’ morphology to their current and photocurent mappings
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Abu-Helo, Alaa. "Implication de GASP-1 dans la modulation de l’activité des agonistes du récepteur bêta-2 adrénergique dans la fonction respiratoire." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAJ024/document.
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GASP1 modulerait le trafic intracellulaire des RCPG après endocytose provoquée par les ligands. Au cours de ce travail nous nous sommes focalisés sur l’interaction de GASP-1 avec le récepteur beta2-adrénergique (B2AR) et ses conséquences fonctionnelles. Les agonistes du récepteur B2AR sont des bronchodilatateurs puissants utilisés dans le traitement de l’asthme. Avec le Dr N. Frossard, nous avons montré qu'un traitement chronique avec un agoniste B2AR induit le développement d'une hyper-réactivitée bronchique chez les souris sauvages mais pas chez les KO GASP1. Ce phénotype n’est pas relié à une différence dans la dégradation du récepteur B2AR entre les souris sauvages et KO GASP-1 mais est corrélé avec une augmentation du niveau de collagène dans les poumons des souris sauvages. Nos résultats indiquent que GASP1 joue un rôle important dans ce phénomène adaptatif qui serait relié à un remaniement des tissus bronchiques dépendant de cette protéine<br>GASP1 have been shown to modulate the postendocytic sorting of different GPCRs.In order to better understand the role of GASP1 in regulating the activity and intracellular traffic king of GPCRs, we have focused our project on the functional consequences of the interaction between GASP1 and beta2-adrenergic receptor (B2AR). B2AR agonists are potent bronchodilators used in the treatment of asthma. With Dr. N. Frossard, we have shown that achronic treatment with a B2AR agonist induces the development of bronchial hyperresponsiveness in wild-type but not in KO GASP1 mice. Furthermore, we have shown that this phenotype is not related to a difference of B2AR receptor degradation between wild type and KO animals but correlates with an increase in collagen levels in the lungs of wild type mice that is not observed in GASP1KO animals. Altogether, our data suggest thatGASP1 is critically involved in these adaptations, which could be related to a GASP1-dependent modification of lung tissues
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Doktor, Christoph. "Die Aussen- und Sicherheitspolitik Österreichs und der Schweiz gegenüber der GASP der Europäischen Union : eine diskurstheoretische Analyse /." Münster [u.a.] : LIT, 2009. http://deposit.d-nb.de/cgi-bin/dokserv?id=3372681&prov=M&dokv̲ar=1&doke̲xt=htm.
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Weir, Douglas. "Noble Gas Collision Induced Vibrational Relaxation of (v=1) para-H2." Thesis, University of Waterloo, 2001. http://hdl.handle.net/10012/1227.
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Close coupling scattering calculations have been conducted for the para spin modification of H<sub>2</sub>-{He, Ne and Ar}. The XC(fit) potential energy surfaces for H<sub>2</sub>-Ne and H<sub>2</sub>-Ar have been used for calculations for these two systems, while a newly fitted version of the Schaefer and Kohler potential energy surface was used for the H<sub>2</sub>-He system. The fitting procedure employs nine modified Lennard-Jones oscillator functions to describe accurately 90% of the original tabulated potential energy surface to better than 12% error. The scattering calculations for H<sub>2</sub>-Arfailed at higher energies due to the presence of a previously undocumented potential energy surface turn-over at R less than 1. 0 Angstroms. Manifold-to-manifold v=1 vibrational relaxation calculations for each of these systems are compared with other experimental and theoretical calculations. These comparisons demonstrate a common discrepancy between previous calculations and the current calculations for each system. The current vibrational relaxation rate constants are generally too small when compared to low temperature values of Audibert et al. and Orlikowski, and the high temperature values obtained by Flower et al. and Dove andTeitelbaum. The current calculations indicate the presence of a dramatic up-turn in the low temperature H<sub>2</sub>-He rate constants. Other experimental and theoretical treatments do not exhibit this same up-turn, which is puzzling. A set of follow-up calculations featuring a larger basis set (such as the {16,12,10,8} Flower et al. basis set) and a larger manifold of included relaxation pathways are needed to improve these calculations.
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Reynders, Frederik Jakobus Wilhelm. "Gas-limited hydrogenation of 1-octene in a packed bed reactor." Diss., University of Pretoria, 2011. http://hdl.handle.net/2263/26555.
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Jiao, Mingzhi. "Microfabricated Gas Sensors Based on Hydrothermally Grown 1-D ZnO Nanostructures." Doctoral thesis, Uppsala universitet, Mikrosystemteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-320183.
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In this thesis, gas sensors based on on-chip hydrothermally grown 1-D zinc oxide (ZnO) nanostructures are presented, to improve the sensitivity, selectivity, and stability of the gas sensors. Metal-oxide-semiconductor (MOS) gas sensors are well-established tools for the monitoring of air quality indoors and outdoors. In recent years, the use of 1-D metal oxide nanostructures for sensing toxic gases, such as nitrogen dioxide, ammonia, and hydrogen, has gained significant attention. However, low-dimensional nanorod (NR) gas sensors can be enhanced further. Most works synthesize the NRs first and then transfer them onto electrodes to produce gas sensors, thereby resulting in large batch-to-batch difference. Therefore, in this thesis six studies on 1-D ZnO NR gas sensors were carried out. First, ultrathin secondary ZnO nanowires (NWs) were successfully grown on a silicon substrate. Second, an on-chip hydrothermally grown ZnO NR gas sensor was developed on a glass substrate. Its performance with regard to sensing nitrogen dioxide and three reductive gases, namely, ethanol, hydrogen, and ammonia, was tested. Third, three 1-D ZnO nanostructures, namely, ZnO NRs, dense ZnO NWs, and sparse ZnO NWs, were synthesized and tested toward nitrogen dioxide. Fourth, hydrothermally grown ZnO NRs, chemical vapor deposited ZnO NWs, and thermal deposited ZnO nanoparticles (NPs) were tested toward ethanol. Fifth, the effect of annealing on the sensitivity and stability of ZnO NR gas sensors was examined. Sixth, ZnO NRs were decorated with palladium oxide NPs and tested toward hydrogen at high temperature. The following conclusions can be drawn from the work in this thesis: 1) ZnO NWs can be obtained by using a precursor at low concentration, temperature of 90 °C, and long reaction time. 2) ZnO NR gas sensors have better selectivity to nitrogen dioxide compared with ethanol, ammonia, and hydrogen. 3) Sparse ZnO NWs are highly sensitive to nitrogen dioxide compared with dense ZnO NWs and ZnO NRs. 4) ZnO NPs have the highest sensitivity to ethanol compared with dense ZnO NWs and ZnO NRs. The sensitivity of the NPs is due to their small grain sizes and large surface areas. 5) ZnO NRs annealed at 600 °C have lower sensitivity toward nitrogen dioxide but higher long-term stability compared with those annealed at 400 °C. 6) When decorated with palladium oxide, both materials form alloy at a temperature higher than 350 °C and decrease the amount of ZnO, which is the sensing material toward hydrogen. Thus, controlling the amount of palladium oxide on ZnO NRs is necessary.
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Jin, Lei. "Catalytic oxidation of 1, 4-dichlorobenzene in gas phase and supercritical water /." Access abstract and link to full text, 1991. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/9136877.
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Mundalamo, Ronnie. "Sustainable capital budgeting by SCOPE-1 greenhouse gas contributors in South Africa." Diss., University of Pretoria, 2015. http://hdl.handle.net/2263/52267.
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The main purpose of this study was to establish whether South African Scope-1 greenhouse gas companies practise sustainable capital budgeting. Furthermore, this research aimed to establish whether, and how, companies adapt capital budgeting tools to embed sustainability impacts when evaluating capital budgets. This study is a cross-sectional descriptive quantitative research about practices of sustainable capital budgeting and the adaptation of capital budgeting tools to incorporate sustainability impacts. Data were collected through an online survey via a Likert-type scale structured questionnaire. Quantitative data were analysed using summary tables, central tendencies, bar graphs, radars, Fisher s Exact Test, and Spearman s rank correlation coefficient ( ), while qualitative data were analysed using patterns and categories. The study concluded that Scope-1 companies practice sustainable capital budgeting because they prioritise sustainability and have motives related to competitive advantage as part of their approach to sustainability. Companies also deal with constraints related to sustainable capital budgeting tools, including discounted cash flows deficiencies and the difficulty in measuring sustainability impacts. A holistic model to incorporate sustainability impacts is still imperative and a PPP model has been suggested. This study contributes to the literature and to business by bridging the gap between sustainability and accounting bodies of knowledge, which are normally regarded as distinct.<br>Mini Dissertation (MBA)--University of Pretoria, 2015.<br>vn2017<br>Gordon Institute of Business Science (GIBS)<br>MBA<br>Unrestricted
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Al-Akwaa, Shaaima. "Synthesis and New Characterization Method of Silicalite-1 Membranes for Gas Separation." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/41577.
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Zeolite membranes have great potential in gas separation applications because of
their unique selective properties. The main challenge is in synthesizing defect-free zeolite
membranes. In this study, we synthesized silicalite-1 zeolite membranes on ceramic
supports composed of Al2O3 and TiO2 using the pore-plugging method. We investigated
the effect of the fill-level in the autoclave during the synthesis on the membrane
performance. In particular, we were interested in determining the conditions at which the
defects' contribution to the total transport is minimized. We adopted and further developed
the approach proposed by Carter (2019) to quantify the permeance contribution through
defects. Comparing the membrane performance before and after calcination, we proposed
several modifications to the original analysis of Carter (2019). Knowing the defect
transport contribution, we determined the corrected diffusivity, an intrinsic property of
zeolite crystals at a given temperature, of several adsorbed gases on silicalite-1 crystals.
The defect's contribution decreased as the autoclave fill-level increased from 94 to
98%. A further increase in the autoclave fill-level introduced more defects and caused the
autoclave lid to rupture. Despite the differences in the membranes' performance arising
from the autoclave fill-level, the corrected diffusivities of CO2, CH4, and N2 in silicalite-1
showed minimal variation from membrane to membrane. This proves the validity of the
proposed characterization method. Moreover, the reported corrected diffusivities are
comparable to the literature's values, found using other characterization methods.
However, none of the previously used methods is as simple and straightforward as the one
we further developed in this study.
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Chen, Lin. "Probing roles of ethylene in leaf gas exchange, growth and development using ACC-deaminase containing rhizobacteria and 1-methylcyclopropene (1-MCP)." Thesis, Lancaster University, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.654943.
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Li, Dan. "Identification and Differentiation of Tier 1 Bacterial Agents Using Gas Chromatography-Mass Spectrometry." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/4053.
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A simple method was developed for detection and differentiation of five Tier 1 bacterial agents, including Bacillus anthracis, Francisella tularensis, Yersinia pestis, Burkholderia pseudomallei and Burkholderia mallei as well as their closely related near neighbors by gas chromatography-mass spectrometry (GC-MS). Generally, different classes of compounds can be used as biomarkers for biowarfare agent detection, including nucleic acids (i.e., DNA or RNA), proteins (i.e., antibodies), carbohydrates (i.e., sugars), lipopolysaccharides, lipids (i.e., fatty acids) and small molecules. One-step thermochemolysis (TCM) was developed to provide GC-MS detectable biomarker signatures, including sugars, fatty acids and small molecules. Solid phase micro-extraction (SPME) was used for biomarker extraction, concentration and introduction into the GC-MS. Statistical algorithms were constructed using a combination of biomarkers for the five agents, which were robust against different growth conditions (medium and temperature). A general GC-MS temperature program was developed for all five Tier 1 bacteria. The total analysis time, including TCM, SPME extraction and GC-MS, is approximately 40 min. The total-ion chromatograms are very different for the five species. The final goal of this research was to develop an accurate, fast, simple, robust and automated method for field application. Therefore, an automated sample preparation system was designed, constructed and tested. The system automatically controls the movement of sample vials from one position to another, crimping of septum caps onto the vials, precise delivery of reagents and TCM reaction times and temperatures. The specific operations of introduction of sample vials, SPME sampling, injection into the GC-MS system and ejection of used vials from the system were performed manually in this study, although they can be integrated into the automated system. Manual SPME sampling is performed by following visual and audible signal prompts for inserting the fiber into and retracting it from the sampling port. A rotating carousel design allows for simultaneous sample collection, reaction, biomarker extraction and analysis of sequential samples. Bacillus species were used to test this autoreactor, and 96% of the samples were correctly identified using a statistical algorithm. This research applies not only to the rapid identification of Tier 1 agents after a biological attack, but should also benefit clinical diagnosis, which is essential to effective treatment.
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Cohen, Ruben Y. "Thermalization of a 1-dimensional Rydberg gas and entanglement distribution across quantum networks." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS281/document.
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Le comportement collectif des atomes de Rydberg est au cœur de nombreux protocoles d'information quantique, notamment de répéteurs quantiques. Cette thèse traite de deux sujets distincts: la dynamique collective de nuages d'atomes de Rydberg et l'utilisation de répéteurs quantiques dans des réseaux complexes. Dans la première partie, nous étudions un système simple composé d'une chaîne 1D d'atomes de Rydberg couplée à un laser résonnant sur la transition vers un niveau de Rydberg dans le régime contenant quelques excitations. Les atomes de Rydberg sont soumis à une forte interaction dipolaire qui tend à empêcher l'excitation simultanée de deux atomes proches l'un de l'autre. C'est ce phénomène de blocage de Rydberg qui fait des atomes de Rydberg d'éminents candidats pour des protocoles d'information quantique. Ce blocage induit une distribution spatiale particulière des excitations le long de la chaîne d'atomes. Le calcul exact de cette distribution est souvent impossible en pratique même numériquement, et des approximations sont a priori nécessaires:- l'approximation des sphères de Rydberg dures: l'interaction dipolaire est modélisée par une sphère centrée autour de chaque excitation, à l'intérieur de laquelle toute autre excitation est impossible;- l'hypothèse de thermalisation: le système est supposé thermaliser, c'est-à-dire qu'après suffisamment de temps, même sans effets dissipatifs, le système tendra vers un état quasi-thermique qui peut être décrit par la physique statistique et plus précisément l'ensemble microcanonique. Cette thèse présente une étude de la thermalisation d'un ensemble 1D d'atomes de Rydberg et, plus particulièrement, de l'acuité des prédictions de l'ensemble microcanonique en supposant l'hypothèse des sphères dures. Nous avons simulé numériquement la dynamique d'un tel système composé de 100 atomes, dans le régime contenant au plus deux excitations dans l'ensemble. De plus, un modèle analytique à 6 dimensions est présenté. Comparant les trois approches, nous montrons que le modèle analytique corrobore la simulation numérique, tandis que simulation et modèle mis ensemble contredisent les prédictions microcanoniques. Dans ce régime, l'utilisation de cet ensemble est donc inadaptée. La seconde partie de cette thèse porte sur la distribution d'intrication dans un réseau de répéteurs quantiques. Ces derniers devraient permettre la communication quantique de deux parties distantes. Ces répéteurs quantiques sont presque toujours connectés en un réseau linéaire. Dans cette thèse, nous explorons les possibilités offertes par des réseaux arbitraires constitués de ces répéteurs connectant une multitude de clients. Nous avons représenté ces réseaux à l'aide de graphes non orientés. Nous avons étudié deux scénarios de routage:- le routage classique d'intrication qui corresponds au cas où des clients, très limités par leurs dispositifs quantiques, souhaitent partager des paires intriqués. Sur ces réseaux, les problèmes de communication sont équivalents à des problèmes de chemins disjoints. Lorsque les clients souhaitant communiquer ensemble (les terminaux) sont choisis par un adversaire, nous avons obtenu deux bornes: l'une proportionnelle au genre topologique, et l'autre au degré minimal du graphe. Nous proposons deux architectures de réseau saturant la plus contraignante, celle due au degré minimal. D'autre part, lorsque les clients sont répartis dans un espace à 2-3 dimensions, nous avons montré une limitation géométrique sur la fraction de clients pouvant communiquer simultanément.- le routage quantique utilisant le codage de réseau, qui correspond au cas où le réseau quantique est composé de petits processeurs quantiques capable d'effectuer des opérations locales. Nous avons étudié un problème de communication, le réseau papillon, où le routage classique de l'intrication entre deux paires de clients est impossible. Grâce au codage de réseau, nous avons résolu ce problème de communication<br>The collective behavior of Rydberg gases is at the heart of many proposals for quantum information. This thesis treats two distinct topics: the collective dynamic of a Rydberg ensemble and the use of quantum repeaters across quantum networks.In the first part of this thesis, we choose to focus on a simple system involving Rydberg atoms: a 1-dimensional Rydberg gas coupled to a laser resonant with the Rydberg transition. Rydberg atoms interact together through the dipole-dipole interaction. This particular feature is used for quantum information purposes, like applying multi-qubits gates for example. This interaction is strong enough so that the dynamic of such system in the regime of few excitations in the gas ensemble is already intractable without any assumptions. One of them is the hardcore Rydberg sphere assumption: we approximate this interaction by a sphere around each excitation inhibiting any second excitation within it. Another one is to suppose that the system thermalizes in such regime; a statistical treatment could then be applied. We have investigated the thermalization of a 1D-Rydberg gas and evaluated the accuracy of the microcanonical ensemble predictions under the first assumption. To do so, we have numerically simulated the dynamic of such system constituted by 100 atoms, in the regime of at most two excitations in the chain, in the initial excitation-less state. Furthermore, we constructed a 6-dimensional analytical model. Comparing the three approaches together, we have concluded that the numerical simulation and the analytical model both agree together but contradicts the microcanonical treatment. In this regime, the microcanonical ensemble is unadapted.In the second part of this thesis, we have studied the distribution of entanglement across a generic quantum network. We have mapped these quantum networks to undirected graphs and studied two different routing scenarios:- the classical routing of quantum entanglement corresponding to the scenario where clients of the network can perform only a single Bell measurement or keep a single qubit. This is the usual model of quantum repeaters. On these networks, peer-to-peer communication problems are equivalent to the vertex disjoint path problem. When the peers are chosen by an adversary, we have found two limitations due to the topological genus and the minimum degree of the graph. We have found two network architectures (almost) saturating the most constraining one, the minimum degree inequality. For the case where the peers are chosen at random, we have studied a specific graph lying in a 2- or 3-dimensional manifold and investigated the trade-off between the quantum links and the number of peers that can communicate simultaneously through the network.- true quantum routing problem (using network coding) corresponding to the situation where the quantum network is composed by small quantum processors that could apply local gates. We focus on a particular communication problem, namely the butterfly network, where classical routing is impossible. Using network coding, this communication is solved
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Das, Elif. "Effect Of Controlled Atmosphere Storage, Modified Atmosphere Packaging And Gaseous Ozone Treatment On The Survival Characteristics Of Salmonella Enteritidis At Cherry Tomatoes." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605337/index.pdf.
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iv
In recent years, outbreaks of infections associated with raw and
minimally processed fruits and vegetables have been reported. Possible
sources for contamination are irrigation water, manure, wash water, handling
by workers and contact with contaminated surfaces. Pathogens can occur on
raw and minimally processed produce at populations ranging from 103 to 109
CFU/g and able to survive and sometimes grow under various storage
conditions. The objective of this study was to analyse the growth/survival of
Salmonella Enteritidis at spot-inoculated or stem-injected cherry tomatoes
during passive modified atmosphere packaging (MAP), controlled
atmosphere (CA) and air storage at 7 and 22°<br>C. Low density polyethylene
(LDPE) with a package size of 10x10 cm2 for 25±<br>2 g tomatoes was used for
MAP storage in which the gas composition equilibrated to 6% O2/ 4% CO2
and a carbon dioxide incubator was used for CA storage in which the CO2
level was monitored and maintained as 5% through the term of storage at 7
and 22°<br>C. During the research, the effect of ozone treatment (5-30 mg/L
ozone gas for 0-20 min) was also considered for surface sanitation. The
results demonstrate that S.Enteritidis can survive and/or grow during the
storage of tomatoes depending on the location site of the pathogen on fruit,
suspension cell density and storage temperature. During MAP, CA and air
storage, S.Enteritidis with initial population of 7.0 log10 CFU/tomato survived
on tomato surfaces with an approximate decrease of 4.0-5.0 log10
CFU/tomato in population within the storage period<br>however, in the case of
initial population of 3.0 log10 CFU/tomato, cells died completely on day 4
during MAP storage and on day 6 during CA and air storage. The death rate
of S.Enteritidis on the surfaces of tomatoes that were stored in MAP was
faster than that of stored in air. Storage temperature was effective on the
survival of S.Enteritidis for the samples stored at ambient atmosphere<br>cells
died completely on day 6 at 7°<br>C and on day 8 at 22°<br>C. Stem scars provided
protective environments for Salmonella<br>an approximate increase of 1.0 log10
CFU/tomato in stem-scar population was observed during MAP, CA and air
storage at 22°<br>C within the period of 20 days. Cells survived with no
significant change in number at 7°<br>C. The development of the microbial
association in tomatoes was dominated by lactic acid bacteria (LAB). The pH
values of the tomatoes changed approximately from 4.0 to 3.0 during the
storage period. LAB grew well under all atmospheric conditions with or
without the presence of S.Enteritidis. Gaseous ozone treatment has
bactericidal effect on S.Enteritidis, inoculated on the surface of the tomatoes.
5 mg/L ozone gas treatment was not effective. 30 mg/L ozone gas treatment
affected surface color.
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Hagey, H. Louis. "Compound catalyst for the production of C¦1-C¦4 hydrocarbons from synthesis gas." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq21065.pdf.
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Vanwalleghem, Gilles. "Adaptations of Trypanosoma brucei to the innate immunity proteins TNF-gas and ApoL-1." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209725.
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This work allowed the first characterization of the three members of the chloride channel CLC family in T.brucei. The TbCLCs are expressed in the two proliferative stages of the parasite and two of their members appear non-essential. The three TbCLCs act as chloride transporters in X.laevis oocytes and some of their biophysical properties were determined. Furthermore, TbCLC-b appeared to be involved in lysis by the human innate immunity protein apoL-1<p>A novel function of T.brucei adenylate cyclases was discovered in their ability to suppress expression of the innate immunity protein TNF-α. The suppression of the innate response occurs before the first peak of parasitemia and reduces the host ability to control the parasite.<p><br>Doctorat en Sciences<br>info:eu-repo/semantics/nonPublished
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Althumayri, Khalid Abdulmohsen M. "Polymers of intrinsic microporosity and incorporation of graphene into PIM-1 for gas separation." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/polymers-of-intrinsic-microporosity-and-incorporation-of-graphene-into-pim1-for-gasseparation(4e8909e1-4c5d-4ba2-b8a3-276295b3d5c4).html.
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Membrane-based gas separation processes are an area of interest owing to their high industrial demand for a wide range of applications, such as natural gas purification from CO2 or H2, and N2 or O2 separation from air. This thesis is focused on developing and investigating polymeric-based membranes. Firstly, novel mixed matrix membranes (MMMs) were prepared, incorporating few-layer graphene in the polymer of intrinsic microporosity PIM-1. Secondly, novel polyphenylene-based polymers of intrinsic microporosity (PP-PIMs) were synthesised. An optimum preparation method of graphene/PIM-1 MMMs (GPMMMs) was established from numbers of experiments. In this study, graphene exfoliation was a step towards GPMMM preparation. Starting from graphene exfoliation in chloroform, as a good solvent for PIM-1, enhancement in graphene dispersibility was obtained with addition of PIM-1. This result helped in GPMMM preparation with high graphene content (up to 4 wt.%). Characterizations techniques such as Raman spectroscopy and scanning electron microscopy (SEM) of GPMMMs, confirmed the few layer graphene content, with morphology changes in the polymeric matrix compared to pure PIM-1.Gas permeability results of GPMMMs showed an enhancement in permeability with low loading graphene (0.1 wt.%) using a relatively low permeability PIM-1 batch, due to high water content. However, less influence of graphene incorporation on permeability was observed with a highly permeable PIM-1 batch. Reduction in permeability over time, termed an ageing effect, is known for a polymer of high-free volume like PIM-1. However, the enhancement of GPMMMs permeability after eight months storage was shown to be retained. Novel PP-PIMs were prepared from novel precursors using a series known organic reactions. PP-PIMs were divided into two groups of polymers based on their polymerization reactions. A group of polymers were prepared from condensation polymerization between bis-catecol monomers and tetrafluoroterephthalonitrile (TFTPN). Another group of polymers were prepared from Diels Alder polymerization between monomers of terminal bisphenylacetylene groups and bis tetraphenylcyclopentadienones (TPCPDs). All of which yielded polymers with apparent BET surface area in the range 290-443 m2 g-1.
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Johnson, Helen Louise. "The evolution of gas kinematics in star-forming field and cluster galaxies since z~1." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12428/.
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A fundamental pursuit of astronomy is to understand how galaxies form and evolve. What drives the decline in the cosmic star formation rate density? Why are high redshift galaxies clumpy and turbulent? How can we explain the emergence of the Hubble sequence? To answer these questions we must unravel a complex interplay of different processes, including gas accretion, star formation, feedback, and environmental effects. Studying the gas kinematics of galaxies can provide valuable insight. In this thesis we use integral field spectroscopy to probe the evolution of star-forming field and cluster galaxies over the past 8 billion years. We first present a multi-wavelength analysis of 27 dusty starburst galaxies in a massive cluster at z~0.4. It is thought that starbursts represent an intermediate phase in the transition from spirals to S0s in dense environments. We combine H-alpha kinematics with far-infrared imaging and millimetre spectroscopy, and find that most galaxies are rotationally supported, with high angular momentum and large cold gas reservoirs. It appears that the starbursts have only recently been accreted to the cluster. To complete the transition to S0s, they must undergo a dynamical heating of the disk, increase in concentration, and reduce their angular momentum by ~40%. We conclude that the most likely way to achieve this is via multiple tidal interactions with other cluster members. We next study the velocity dispersion properties of 472 galaxies observed as part of the KMOS Redshift One Spectroscopic Survey (KROSS). Most galaxies at this epoch are rotationally supported, but dynamically hot and highly turbulent. In order to make robust kinematic measurements, we model the effects of beam smearing using a series of mock KMOS data cubes. We then combine KROSS with data from the SAMI survey (z~0.05) and an intermediate redshift MUSE sample (z~0.5), and find that while there is a weak trend between velocity dispersion and stellar mass, at fixed mass there is a strong increase in velocity dispersion with redshift. At all redshifts, galaxies appear to follow the same weak trend of increasing velocity dispersion with star formation rate. We also test the predictions of two analytic models which suggest that turbulence in the ISM is driven by gravitational instabilities or stellar feedback. However we find that further observations are required to rule-out either model. Finally, to understand the role of galaxy kinematics in “crystallising” the Hubble sequence, we study the HST images of 231 KROSS galaxies. We quantify differences in morphology using the asymmetry parameter. This metric correlates very well with our visual interpretation of “clumpiness”, however there are no strong trends as a function of galaxy kinematics. On average, the velocity dispersion of clumps is consistent with the underlying disk, and there is no evidence to suggest that these star-forming regions are preferentially located towards the outskirts of the galaxy. We propose that adaptive optics assisted IFU observations would provide further insight, allowing us to test clump evolution theories and to study the radial distribution of angular momentum.
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Savard, Lalancette Jimmy. "Le gène suppresseur de métastases Growth Arrest-Specific 1 (Gas1) est réprimé épigénétiquement chez le mélanome métastatique." Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/30532/30532.pdf.
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Nous avons récemment découvert que le gène Gas1 agit comme un suppresseur de métastases chez le mélanome. Ce gène pourrait être utilisé pour d’éventuelles thérapies contre la métastase. Afin de découvrir le mécanisme réprimant l’expression de Gas1 chez les cellules métastatiques, nous avons utilisé des ChIP, des inhibiteurs chimiques et des petits ARN interférents contre des molécules susceptibles de réprimer Gas1. Chez le mélanome métastatique murin B16-F10, nous avons observé plusieurs groupements méthyles sur l’îlot CpG du promoteur de Gas1, ainsi que la marque de répression H3K9me3 et l’absence de la polymérase II. Chez les cellules humaines C8161 et Lox-IMVI, nous avons découvert qu’il y avait une forte présence d’acétylation au niveau de l’histone 3 et de polymérase II. Par ailleurs, nous avons prouvé que c-MYC et BRD4 étaient impliqués dans la régulation de GAS1. Finalement, ces résultats pourront être utilisés pour développer d’éventuelles thérapies contre la métastase.
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Savard-Lalancette, Jimmy. "Le gène suppresseur de métastases Growth Arrest-Specific 1 (Gas1) est réprimé épigénétiquement chez le mélanome métastatique." Master's thesis, Université Laval, 2013. http://hdl.handle.net/20.500.11794/24676.
Full textAbstract:
Nous avons récemment découvert que le gène Gas1 agit comme un suppresseur de métastases chez le mélanome. Ce gène pourrait être utilisé pour d’éventuelles thérapies contre la métastase. Afin de découvrir le mécanisme réprimant l’expression de Gas1 chez les cellules métastatiques, nous avons utilisé des ChIP, des inhibiteurs chimiques et des petits ARN interférents contre des molécules susceptibles de réprimer Gas1. Chez le mélanome métastatique murin B16-F10, nous avons observé plusieurs groupements méthyles sur l’îlot CpG du promoteur de Gas1, ainsi que la marque de répression H3K9me3 et l’absence de la polymérase II. Chez les cellules humaines C8161 et Lox-IMVI, nous avons découvert qu’il y avait une forte présence d’acétylation au niveau de l’histone 3 et de polymérase II. Par ailleurs, nous avons prouvé que c-MYC et BRD4 étaient impliqués dans la régulation de GAS1. Finalement, ces résultats pourront être utilisés pour développer d’éventuelles thérapies contre la métastase.
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Liao, Chaqing. "Gas ejector modeling for design and analysis." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3206.
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Elmqvist-Möller, Christel. "1-D simulation of turbocharged SI engines : focusing on a new gas exchange system and knock prediction." Licentiate thesis, KTH, Machine Design (Div.), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4218.
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<p>This licentiate thesis concerns one dimensional flow simulation of turbocharged spark ignited engines. The objective has been to contribute to the improvement of turbocharged SI engines’ performance as well as 1 D simulation capabilities.</p><p>Turbocharged engines suffer from poor gas exchange due to the high exhaust pressure created by the turbine. This results in power loss as well as high levels of residual gas, which makes the engine more prone to knock.</p><p>This thesis presents an alternative gas exchange concept, with the aim of removing the high exhaust pressure during the critical periods. This is done by splitting the two exhaust ports into two separate exhaust manifolds.</p><p>The alternative gas exchange study was performed by measurements as well as 1-D simulations. The link between measurements and simulations is very strong, and will be discussed in this thesis.</p><p>As mentioned, turbocharged engines are prone to knock. Hence, finding a method to model knock in 1-D engine simulations would improve the simulation capabilities. In this thesis a 0-D knock model, coupled to the 1-D engine model, is presented</p>
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Elmqvist-Möller, Christel. "1-D simulation of turbocharged SI engines : focusing on a new gas exchange system and knock prediction /." Stockholm : KTH, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4218.
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Simo, Aline. "Physical properties of vanadium dioxide nanoparticles: application as 1-d nanobelts room temperature for hydrogen gas sensing." Thesis, University of the Western Cape, 2013. http://hdl.handle.net/11394/4581.
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Philosophiae Doctor - PhD<br>Transition metal oxides magneli phases present crystallographic shear structure which is of great interest in multiple applications because of their wide range of valence, which is exhibited by the transition metals. The latter affect chemical and physical properties of the oxides. Amongst them we have nanostructures VO2 system of V and O components which are studied including chemical and physical reactions based on non-equilibrium thermodynamics. Due to their structural classes of corundum, rocksalt, wurtzite, spinel, perovskite, rutile, and layer structure, these oxides are generally used as catalytic materials which are prepared by common methods under mild conditions presenting distortion or defects in the case of VO2. Existence of an intermediate phase is proved using an x-ray thermodiffraction experiment providing structural information as the nanoparticles are heated. Potential application as gas sensing device has been the first time obtained due to the high surface to volume ratio, and good crystallinity, purity of the material and presence of suitable nucleating defects sites due to its n-type semiconductor behavior. In addition, annealing effect on nanostructures VO2 nanobelts shows a preferential gas reductant of Ar comparing to the N2 gas. Also, the hysteresis loop shows that there is strong size dependence to annealing treatment on our samples. This is of great interest in the need of obtaining high stable and durable material for Mott insulator transistor and Gas sensor device at room temperature.
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Hurley, Margaret M. "Analysis of the dipolar lattice gas as a model for self-assembly in 1 and 2-dimensional systems /." The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487780393265179.
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Erturk, Mehmet. "Efficiency Analysis Of Turkish Natural Gas Distribution Companies By Using Dea Method." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610796/index.pdf.
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The history of natural gas in Turkey started in 1970s by the usage of domestic gas in cement factories. However, natural gas began penetrating the energy market in 1980s with the usage of natural gas in Ankara. In the following years, the number of cities using natural gas reached six. Then, a new era started with the enactment of Natural Gas Market Law in 2001 and 53 distribution tenders have been realized by Energy Market Regulatory Authority until 2009. This thesis analyzes the performance of 38 Turkish natural gas distribution companies by using a non-parametric method, Data Envelopment Analysis. The results are used to determine the most proper model specification, to detect the important criteria affecting the efficiency levels and to find the common characteristics of the most inefficient firms. The results show that public firms compared to private firms, non-tender firms compared to tender firms,
large firms compared to small firms and firms operating in more developed areas compared to firms operating in underdeveloped areas utilize resources and manage costs more efficiently. However, we can not get a certain conclusion about the comparison of old firms and new firms. Lastly, we try to detect the common characteristics of the most inefficient firms and find that the major problem is low delivery amount.
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Mert-gauthier, Esra. "Modeling Permian Petroleum System Of Northeast Netherlands: Hydrocarbon Generation And Migration." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612508/index.pdf.
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Groningen Gas Field is located within the southern part of the South Permian Basin in
the northeast Netherlands. Since several wells have been producing from the
Carboniferous-Permian Petroleum System, the field is considered as mature for
hydrocarbon exploration. More detailed work is necessary to evaluate further
exploration and development opportunities. Thus, evaluation of the subsurface has been
carried out as part of the petroleum system concept by using the basin modeling.
In this study, seismic interpretation was performed by using 3-dimensional seismic and
borehole data with Petrel software in order to understand stratigraphy and structural
settings of the area. PetroMod basin analysis software has been used for 1-dimensional
and 2-dimensional basin modeling study by integrating interpreted geophysical,
geological and geochemical data.
Results show that the most recognized traps were formed during pre-Zechstein, and the
major generation-migration and accumulation of hydrocarbon commenced during
Middle Jurassic and continues to the present time. Since the timing of main hydrocarbon
generation varies spatially and has begun after trap formation, both early and late
migration enhances the potential of the porous Upper Rotliegend reservoirs. Prospective
hydrocarbon traps may occur in the southwestern regions of the basin due to shallower
depth of burial. On the other hand, all local structural highs that formed as a result of
salt movement create potential traps in the region.
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Cornetero, Muro Blanca Alicia, Centurion Zulma De Jesus Cortijo, Rivera Natalie Liz Nakamura, and Allcca Jorge Luis Navarro. "Desarrollo de un plan para la Dirección Del Proyecto: Ampliación de la Red de Gas de Cálidda – Tramo 1." Master's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2016. http://hdl.handle.net/10757/593334.
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La presente tesis tiene como objetivo aplicar los lineamientos de la Guía de los Fundamentos para la Dirección de Proyectos (Guía del PMBOK®) – Quinta edición a la dirección de un proyecto que fue desarrollado por GYM S.A. del grupo Graña y Montero en el año 2010 para la empresa Cálidda – Gas Natural de Lima y Callao S.A., el mismo que es parte de un proyecto integral. Este proyecto integral comprende la construcción de la Ampliación de Red de Gas que se inicia en un City Gate, recorre 39 Km de tubería en tres tramos, cruzando los distritos de Lurín y Pachacámac, hasta llegar a un Terminal Station que a su vez se interconecta con la red de gas existente, ubicada aproximadamente a 1.5 Km del trébol de Javier Prado con la Vía Evitamiento. La dirección del proyecto que se desarrollará se aplicará al Tramo 1 de esta red de Gas desde el City Gate ubicado en el Distrito de Lurín, hasta el empalme al tramo 2 de dicha red.<br>Tesis
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Aydin, Ayse Esra. "European Union." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614743/index.pdf.
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This thesis examines the bilateral relations of European Union and Russia in terms of energy trade. The main question of this thesis is whether European Union could realize its energy strategies of supply security and supply diversification in its natural gas trade with Russia. The main argument of this thesis is<br>Russia has been undermining the EU&rsquo<br>s energy strategy, by using the contradictions between the EU&rsquo<br>s energy strategy priorities of supply security and supply diversification. Emphasizing the significance of supply security for the European Union, Russia undermines the EU-sponsored projects of supply diversification. The fact that, Russia will be the principal supplier of natural gas to Europe, is likely remain as the key actor in energy market of EU. However, Russia is also dependent on EU for its hydrocarbon exports. Consequently Russia&rsquo<br>s role as EU&rsquo<br>s primary supplier in natural gas , and EU&rsquo<br>s role as Russia&rsquo<br>s main hydrocarbon importer, are likely to be the main factor that will continue to shape the thereon energy security in the foreseeable future.
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Rudnick, Gregory, Jacqueline Hodge, Fabian Walter, et al. "Deep CO(1–0) Observations of z = 1.62 Cluster Galaxies with Substantial Molecular Gas Reservoirs and Normal Star Formation Efficiencies." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/627107.
Full textAbstract:
We present an extremely deep CO(1-0) observation of a confirmed z = 1.62 galaxy cluster. We detect two spectroscopically confirmed cluster members in CO(1-0) with signal-to-noise ratio >5. Both galaxies have log (M-star/M-circle dot) > 11 and are gas rich, with M-mol/(M-star + M-mol) similar to 0.17-0.45. One of these galaxies lies on the star formation rate (SFR)-M-star sequence, while the other lies an order of magnitude below. We compare the cluster galaxies to other SFR-selected galaxies with CO measurements and find that they have CO luminosities consistent with expectations given their infrared luminosities. We also find that they have gas fractions and star formation efficiencies (SFE) comparable to what is expected from published field galaxy scaling relations. The galaxies are compact in their stellar light distribution, at the extreme end for all high-redshift star-forming galaxies. However, their SFE is consistent with other field galaxies at comparable compactness. This is similar to two other sources selected in a blind CO survey of the HDF-N. Despite living in a highly quenched protocluster core, the molecular gas properties of these two galaxies, one of which may be in the process of quenching, appear entirely consistent with field scaling relations between the molecular gas content, stellar mass, star formation rate, and redshift. We speculate that these cluster galaxies cannot have any further substantive gas accretion if they are to become members of the dominant passive population in z < 1 clusters.
34
Hause, Stephan [Verfasser], Gunter [Akademischer Betreuer] Wolf, Karlheinz [Akademischer Betreuer] Friedrich, and Karl [Akademischer Betreuer] Hilgers. "Genexpression von Gas2L 1 und Gas2 in Podozyten unter Einfluss von advanced Glycation Endproducts / Stephan Hause. Gutachter: Gunter Wolf ; Karlheinz Friedrich ; Karl Hilgers." Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2015. http://d-nb.info/1079217576/34.
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35
McPherson, Matthew Joseph. "Control of water and toxic gas adsorption in metal-organic frameworks." Thesis, University of St Andrews, 2016. http://hdl.handle.net/10023/16489.
Full textAbstract:
The research presented in this thesis aims to determine the effectiveness of the uptake of toxic gases by several MOFs for future use in gas-mask cartridges, and to attempt to compensate for any deficiencies they show in “real-world” conditions. The main findings of this thesis confirm that MOFs are suitable candidates for the use in respirator cartridge materials and provide high capacity for adsorption of toxic gases like ammonia and STAM-1 in particular showed an impressive improvement in humid conditions, which normally decrease the performance of MOFs made from the same materials, such as HKUST-1. STAM-1's improved performance in humid conditions is attributed to the structural shift it displays upon dehydration and rehydration and this was shown to be the case in a structural analogue, CuEtOip, which was synthesised in the author's research group. This analogue was analysed using a combination of single crystal XRD and solid state MAS-NMR, both of which showed the structural change occurring and displays similar gas sorption behaviours, suggesting that this mechanism is the source of STAM-1's improved performance in humid conditions. This thesis also examines the “Armoured MOF” process and investigates the transferability of the process of deposition of mesoporous silica onto MOFs with vastly different properties and synthetic methods compared to those published in the original publication. Alongside this, attempts to protect MOFs using mesoporous silicates were investigated for their viability.
36
Kutluer, Kutlu. "Electrical, Optical, And Noise Characterizations Of Mwir Type-ii Inas/gasb Superlattice Single Pixel Detectors." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614737/index.pdf.
Full textAbstract:
Detection of mid-wavelength infrared radiation is crucial for many industrial, military and biomedical applications. Photon detectors in the market can operate at only low temperature which increases weight, power consumption and total cost. Type-II InAs/GaSb superlattice infrared detectors are expected to have a major role in the infrared detector market with providing high quality detection characteristics at higher temperatures. Therefore, in the past decade, there has been an increasing interest in infrared detectors based on type-II InAs/GaSb superlattice technology due to their long range adjustable bandgap, low tunneling current and Auger recombination rates which bring potential of high temperature operation. Characterization of this photodiodes requires detailed investigations on different aspects.
This study focuses on various optical and electrical characterization techniques for single pixel infrared detectors: responsivity characterization using FTIR and blackbody source, dark I-V and R-V characterizations, response time measurement. Characterizations of detector noise with respect to frequency and bias voltage are studied in detail. These characterization techniques are carried out in order to observe the effects of design with three different &ldquo<br>standard&rdquo<br>and a new &ldquo<br>N&rdquo<br>structure designs and also to understand the effects of surface passivation with atomic layer deposited Al2O3 layer and ordinary PECVD deposited Si3N4 and SiO2 layers. When standard photodiodes are compared, we observed that the one with the thickest active absorber region has the highest response and dark current density values. &ldquo<br>N&rdquo<br>structure design photodiode has very low dark current density while its optical performance is not as high as the standard designs. Si3N4 passivation degrades both optical and electrical performances. SiO2 and Al2O3 passivation layers improve optical and electrical characteristics of photodiodes. Theoretical and experimental dark current noise values of SiO2 passivated sample in agreement up to 0.18V reverse bias while those values of unpassivated and Si3N4 passivated samples agree only at zero bias. Temperature dependent R-V characteristics of photodiodes are analyzed and the surface limited activation energy is calculated in order to investigate the additional noise. At the end, surface recombination noise is proposed to cover the deficit on the noise calculation.
37
Soufi, Jihène. "Traitement des gaz d’échappement des groupes électrogènes alimentés par des gasoils, fuels marines ou bio-huiles : élimination des HAP en présence ou non de SOx." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1120.
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Kucukbahar, Duygu. "Modeling Monthly Electricity Demand In Turkey For 1990-2006." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609318/index.pdf.
Full textAbstract:
Factors such as economical development, rapid increase in population and climate change increased electricity demand in Turkey as well as in other countries. Thus, using the correct methods to estimate short, medium and long term electricity demand forms a basis for the countries to develop their energy strategy. In this study, monthly electricity demand of Turkey is estimated. First, the effect of natural gas price and
consumption to electricity demand and elasticities are searched with a simple regression model. Although, natural gas is known as a substitute of electricity, natural
gas consumption and natural gas over electricity price ratio are found to be nearly inelastic. Second part includes two models and cointegration relation is investigated
in nonstationary industry production index, electricity consumption per capita and electricity prices series in the first one. An error correction model is then formed with
an additional average temperature variable and 12 months electricity demand is forecasted. In the second one, heating degree-days and cooling degree-days are used instead of the average temperature variable and a new error correction model is formed. The first model performs better than the second one, indicating the seasonality of electricity consumption during a year. The results of both models are
also compared with previous studies to investigate the effect of different weather variables.
39
Samadov, Hidayat. "Analyzing Reservoir Thermal Behavior By Using Thermal Simulation Model (sector Model In Stars)." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613336/index.pdf.
Full textAbstract:
It is observed that the flowing bottom-hole temperature (FBHT) changes as a result of production, injection or shutting the well down. Variations in temperature mainly occur due to geothermal gradient, injected fluid temperature, frictional heating and the Joule-Thomson effect. The latter is the change of temperature because of expansion or compression of a fluid in a flow process involving no heat transfer or work. CMG STARS thermal simulation sector model developed in this study was used to analyze FBHT changes and understand the reasons. Twenty three main and five additional cases that were developed by using this model were simulated and relation of BHT with other parameters was investigated. Indeed the response of temperature to the change of some parameters such as bottom-hole pressure and gas-oil ratio was detected and correlation was tried to set between these elements. Observations showed that generally FBHT increases when GOR decreases and/or flowing bottom-hole pressure (FBHP) increases. This information allows estimating daily gas-oil ratios from continuously measured BHT. Results of simulation were compared with a real case and almost the same responses were seen. The increase in temperature after the start of water and gas injection or due to stopping of neighboring production wells indicated interwell communications. Additional cases were run to determine whether there are BHT changes when initial temperature was kept constant throughout the reservoir. Different iteration numbers and refined grids were used during these runs to analyze iteration errors<br>however no significant changes were observed due to iteration number differences and refined grids. These latter cases showed clearly that variations of temperature don&rsquo<br>t occur only due to geothermal gradient, but also pressure and saturation changes. On the whole, BHT can be used to get data ranging from daily gas-oil ratios to interwell connection if analyzed correctly.
40
Ghazanfari, Nader. "Rapidly Rotating Ultracold Atoms In Harmonic Traps." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613282/index.pdf.
Full textAbstract:
In this study we investigate the properties of trapped atoms
subjected to rapid rotations. The study is divided into two distinct
parts, one for fermions, another for bosons. In the case of the
degenerate Fermi gas we explore the density structure of
non-interacting cold atoms when they are rotated rapidly. On the
other hand, for rapidly rotating two component Bose condensate, we
search for new lattice structures in the presence of contact and
dipolar interactions.
First, the density structure of Fermi gases in a rotating trap is
investigated. We focus on the anisotropic trap case, in which two
distinct regimes, two and one dimensional regimes, depending on
rotation frequency and anisotropy are observed. Two regimes can be
illustrated by a simple description of maximum number of states
between two Landau levels, which is strongly related to the
dimensionality of the system. The regimes are separated from each
other by a minimum point in this description. For small anisotropy
values the density profiles show a step structure where each step is
demonstrated by an elliptical plateau. Each plateau represents a
Landau level with a constant density. The local density
approximation describes the two dimensional regime with a perfect
similarity in the structure of fermion density. The case for one
dimensional regime is a little different from the two dimensional
case. For large anisotropy values the Friedel oscillation is the
dominant aspect of the density profiles. The density profiles show
gaussian structure along the direction of strong trapping, and a
semicircular form with prominent oscillations along the weak
confining direction. Again, the system is nicely described by local
density approximation in this regime. A smooth crossover between two
regimes is observed, with a switching from a step structure profile
to a soft edge transition with Friedel oscillations. At finite
temperatures, the step structures are smeared out in two dimension.
In one dimensional regime the Friedel oscillations are cleaned as
soon as the temperature is turned on.
The second part of the study is devoted to the investigation of
different lattice structures in two component Bose condensates
subjected to very fast rotation, this time in the presence of
interactions. We explore the existence of new vortex lattice
structures for dipolar two component condensates scanning a wide
range of interaction strengths. We introduce a phase diagram as a
function of intra and inter-component interactions showing different
type of vortex lattice structures. New types of lattice structures,
overlapped square and overlapped rectangular, emerge as a
result of dipolar interactions and s-wave interaction for a two
component condensate. The region where the attractive
inter-component interactions dominate the repulsive interactions, the
overlapped lattices are formed. The intra-component interactions,
which defines the behavior of each component inside, result in
different type of lattices by changing the strength of interactions.
Two different limits of phase diagram reproduce the results of
ordinary two component and dipolar one component Bose condensates.
The results of calculation are in agreement with the results of
previous studies for two regimes.
41
Tawalbeh, Muhammad. "Silicalite-1 Membranes Synthesis, Characterization, CO2/N2 Separation and Modeling." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/30330.
Full textAbstract:
Zeolite membranes are considered to be a promising alternative to polymeric membranes and they have the potential to separate gases under harsh conditions. Silicalite-1 membranes in particular are easy to prepare and suitable for several industrial applications. In this research project, silicalite-1/ceramic composite membranes were prepared using the pore plugging hydrothermal synthesis method and supports with zirconium oxide and/or titanium oxide as active layers. The effect of the support’s pore size on the morphology and permeation performance of the prepared membranes was investigated using five supports with different active layer pore sizes in the range of 0.14 – 1.4 m.
The prepared membranes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), electron diffraction spectrometer (EDS), single gas and binary gas mixtures permeation tests. The results confirmed the presence of a typical silicalite-1 zeolite structure with a high internal crystalline order grown inside the pores of the active layer of the supports, with a dense film covering most of the supports active layers. Silicalite-1 crystals in the prepared membranes were preferably oriented with either a- or b-axes perpendicular to the support surface.
Single gas permeation results illustrated that the observed permeances were not directly related to the kinetic diameter of permeants. Instead, the transport of the studied gases through the prepared membranes occurred by adsorption followed by surface diffusion mechanism. Binary gas tests performed with CO2 and N2 mixtures showed that the prepared membranes were selective and very permeable with CO2/N2 permselectivities up to 30 and a CO2 permeances in the order of 10-6 mol m-2 Pa-1 s-1.
A model was developed, based on Maxwell−Stefan equations and Extended Langmuir adsorption isotherm, to describe the transport of binary CO2 and N2 mixtures through the prepared silicalite-1 membranes. The model results showed that the exchange diffusivities (D12 and D21) were less dependent on the feed pressure and feed composition compared to the permeances and the permselectivities. Hence, they are more appropriate to characterize the intrinsic transport properties of the prepared silicalite-1 membranes.
42
Lee, Kyung Ha. "A comparative study of selected violin works of Isang Yun Gasa für Violine und Klavier (1963) and Sonate für Violine und Klavier Nr. 1 (1991) /." Columbus, Ohio : Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=osu1243887615.
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Karabulut, Orhan. "Structural, Electrical And Optical Characterization Of N- And Si-implanted Gase Single Crystal Grown By Bridgman Method." Phd thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1135755/index.pdf.
Full textAbstract:
Single crystals of GaSe were grown from the melt using 3-zone vertical Bridgman-Stockbarger system. In order to determine the doping effect, nitrogen and silicon ions were implanted to the grown crystals. Surface morphology and stoichiometry were examined using scanning electron microscope equipped with EDAX and structure properties were examined by x-ray diffraction technique. It was observed that the resulting ingot was stoichiometric and the structure was hexagonal. To identify the effects of ion implantation on the physical properties of the samples depending on annealing<br>electrical conductivity, hall measurements, current-voltage characteristics, photoconductivity and photoluminescence measurements were carried out in the temperature range of 100-450 K. Also spectral transmission measurements were carried out for all the samples at room temperature.
It was observed that both N- and Si- implantation followed by annealing process decreased the resisitivity values from 107 to 103 (&<br>#61527<br>-cm). Temperature dependent conductivity measurements were analyzed to deduce the dominant transport mechanisms. The trap levels were also investigated by the space charge limited currents (SCLC) measurements. The temperature dependence of hole concentrations showed that as-grown, N- and Si-implanted samples behave as partially compensated p-type semiconductors. Using suitable statistical method, transport parameters such as acceptor level, donor and acceptor concentrations were extracted from the experimental data.
Trapping centers and recombination mechanisms were determined from the temperature dependent photoconductivity measurements by investigating the relation between photocurrent and illumination intensity. N- and Si- implantation effects on GaSe were also examined by spectral photoconductivity and transmission measurements. And lastly, radiative recombination mechanisms in as-grown GaSe were investigated through photoluminescence (PL) measurements and the information related to the structural defects, the exciton levels and the structure of the forbidden gap were investigated.
44
Karaagac, Hazbullah. "Structural, Electrical And Optical Characterization Of Ge -implanted Gase Single Crystal Grown By Bridgman Method." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12606522/index.pdf.
Full textAbstract:
In this work, structural, electrical and optical characterization of as-grown, Ge-implanted, and annealed GaSe single crystals grown by using 3-zone vertical Bridgman-Stockbarger system, have been studied by carrying out X-ray Diffraction (XRD), electrical conductivity, Hall effect, photoconductivity, and spectral transmission measurements. The temperature dependent electrical conductivity of these samples have been measured between 100 and 400 K. As a result, it was observed that upon implanting GaSe with germanium following annealing process, the resistivity is reduced from 2.1x109 to 6.5x105 &<br>#937<br>-cm. Also it was found that Ge-implantation followed by annealing at 500 oC increases the conductivity in exponential fashion. From the temperature dependent conductivities, the activation energies have been found to be 4, 34 and 314 meV for as-grown, 36 and 472 meV for as-implanted, and 39 and 647 meV for implanted and annealed at 500 oC GaSe single crystals.
Using XRD measurements it was observed that there is an increase in peak intensities at specific annealing temperatures (300 and 500 C) and a decrease in higher annealing temperatures (700 C).
Temperature dependent carrier concentration and Hall mobility measurement were performed in the temperature range of 230 - 410 and 100 - 400 K for as-grown and Ge-implanted and annealed GaSe samples, respectively. All of the samples in this study were found to be p-type with the help Hall measurements. In addition, the density of donor and acceptor atoms are found for each sample and results are compared with each other.
In addition, using photoconductivity measurement the relation between photocurrent and illumination intensity and the character of photoconduction were determined. As a result it was found that while at specific temperature intervals impurity scatterings are dominant, in other intervals phonon scatterings start to dominate.
Finally, in order to determine annealing dependent change of band gap of unimplanted and Ge-implanted GaSe samples at room temperature, the transmission measurement have been carried out as a optical characterization part of our study. As a consequence of this measurement it was observed that there is almost no considerable change in optical band gap of samples with increasing annealing temperatures for as-grown GaSe samples and a slight shift of optical band gap toward to high energy for Ge-implanted samples with annealing process.
45
Okuroglu, Sule. "An Analysis Of Metafictional Self-reflexivity In Laurence Sterne." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12606560/index.pdf.
Full textAbstract:
This thesis evaluates metafictional self-reflexivity, and presents it within the scope of certain structuralist and post-structuralist approaches especially by referring to William Gass&rsquo<br>definition of metafiction and Raymond Federman&rsquo<br>s theories on the devices of metafiction. Then aspects of the works of William Gass&rsquo<br>Willie Master&rsquo<br>s Lonesome Wife and Laurence Sterne&rsquo<br>s The Life and Opinions of Tristram Shandy are discussed within this framework.
46
Soydas, Belma. "Characterization Of Zeolite Membranes By Gas Permeation." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610603/index.pdf.
Full textAbstract:
Zeolite membranes are attractive materials to separate gas and liquid mixtures.
MFI is a widely studied zeolite type due to its ease of preparation and
comparable pore size with the molecular size of many substances. In this
study MFI type membranes were synthesized over porous &<br>#945<br>-Al2O3 supports
and characterized with XRD, SEM and gas permeation measurements.
In the first part of this study the effect of soda concentration of the synthesis
solution on the membrane morphology and crystal orientation was investigated.
The synthesis was carried out from solutions with a molar composition of (0-
6.5)Na2O:25SiO2:6.9TPABr:1136H2O at 150oC. At soda concentrations
between 0.45 and 1.8 the membrane layers with (h0h)/c-directed orientation
were obtained. At lower and higher soda concentrations membrane layer
formed from randomly oriented crystals. The (h0h)/c-oriented membranes
showed H2/n-C4H10 ideal selectivities of 478 and 36 at 25°<br>C and 150°<br>C,
respectively.In the second part, MFI membranes were synthesized from mixtures with
different concentrations of template molecules. Tetrapropylammonium
hydroxide, tetrapropylammonium bromide or mixture of both types were used
as template. The nucleation period, the size of MFI crystals, membrane
thickness decreased as the tetrapropylammonium hydroxide concentration
increased. Besides conversion of SiO2 in the synthesis solution to MFI passed
through a maximum with increasing concentration of tetrapropylammonium
hydroxide in the synthesis solution. When tetrapropylammonium bromide
was used as template thicker membranes were obtained.
In the third part MFI type membranes with a thickness of 1.5-2 &<br>#956<br>m were
synthesized by mid-synthesis addition of silica to the synthesis medium. The
membranes synthesized with and without mid-synthesis addition of silica have
n-C4H10/i-C4H10 ideal selectivities of 47 and 8 at 100oC, respectively. The
change of composition during the synthesis increases the crystal growth rate
and the size of the crystals forming the membrane, thus better quality
membranes can be obtained by mid-synthesis addition of silica to the synthesis
medium.
In the last part of this study, thin MFI type zeolite membranes were synthesized
in a recirculating flow system at 95°<br>C on the inner side of the tubular &<br>#945<br>-
alumina supports. A membrane synthesized by two consecutive synthesis steps
had a separation selectivity of 38 and 86 for equimolar mixtures of n-
C4H10/CH4 and n-C4H10/N2 at 25oC, respectively. The membrane selectively
permeated large n-C4H10 over small CH4 and N2, suggesting that the separation
is essentially adsorption-based and the membrane has few nonselective
intercrystalline pores.
47
Celiker, Dilara Gulcin. "Post-paleogene Deformation In Northernmost Tip Of Tuzgolu Fault Zone (pasadag, South Of Ankara), Turkey." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611376/index.pdf.
Full textAbstract:
The research area is located to the northern tip of Tuzgolu fault zone in the junction of neotectonic structures, namely, EskiSehir-Cihanbeyli, Sungurlu-Kirikkale and Tuzgö<br>lü<br>fault zones (Central Anatolia).
The study is carried out in Paleocene sequences of PaSadag group on the structural analysis of bed, gash vein, fault and fault plane slippage data. The method of study based on i) the rose and stereo analysis of the planar structure (beds, gash veins and faults) on ROCKWORKS 2009 software and ii) on fault slip analysis on ANGELIER 1979 software.
The bed analyses done on 605 measurements manifest N10°<br>-20°<br>E bedding attitude. The analysis done on 64 gash veins shows a general trend of NNE-SSW (N15°<br>E). The final analysis done on 160 fault planes pointed out a general trend of NNWSSE (N20°<br>W).
Analysis based on the fault plane slip data manifest two stages of faulting under almost NE-SW compression during post-Paleocene &ndash<br>pre-Miocene period and one stage of faulting under WNW-ESE extension most probably during post-Miocene.
To conclude, the Paleocene sequences are deformed continuously under WNW-ESE directed compression which is followed by a NE-SW to N-S compression resulted in the development of a reverse to dextral strike slip faulting during post-Paleocene &ndash<br>pre-Miocene period.
48
Hughes, Dimitri O. "A hardware-based transient characterization of electrochemical start-up in an SOFC/gas turbine hybrid environment using a 1-D real time SOFC model." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41229.
Full textAbstract:
Solid oxide fuel cell/gas turbine (SOFC/GT) hybrid systems harness the capability to operate nearly 15 to 20 percentage points more efficiently than standard natural gas or pulverized coal power plants. Though the performance of these systems is quite promising, a number of system integration challenges, primarily with regards to thermal transport, still remain. It is for that reason that the Hybrid Performance Project (HyPer) facility, a Hardware-in-the-Loop SOFC/GT hybrid simulator, was built at the National Energy Technology Laboratory in Morgantown, WV. The HyPer facility couples an actual gas turbine with a combination of hardware and software that are used to simulate an actual SOFC. The facility is used to empirically address the system integration issues associated with fuel cell/gas turbine hybrids. Through this dissertation project, the software component of the SOFC simulator was upgraded from a 0-D lumped SOFC model to a 1-D, distributed, real-time operating SOFC model capable of spatio-temporal characterization of a fuel cell operating with a gas turbine in a hybrid arrangement. Once completed and verified, the upgraded HyPer facility was used to characterize the impact of cold air by-pass and initial fuel cell load on electrochemical start-up in an SOFC/GT hybrid environment. The impact of start-up on fuel cell inlet process parameters, SOFC performance and SOFC distributed behavior are presented and analyzed in comparative manner. This study represents the first time that an empirical parametric study, characterizing system operation during electrochemical start-up has been conducted.
49
Figueiredo, Wallace Torres de. "Elucidation of catalytic events at atomic level in CuNi1-/CeO2 (0<<1) nanoparticles applied to the reverse water-gas shift (RWGS) reaction." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/169734.
Full textAbstract:
A molécula de CO2 é a principal responsável pelas consequências negativas do efeito estufa. Os números cada vez maiores associados à emissão de CO2 na atmosfera têm atraído a atenção de cientistas na busca de novos catalisadores para reações de dissociação de CO2. Simultaneamente, vários eventos atômicos podem influenciar as propriedades catalíticas de tal sistema, como o efeito de forte interação metal-suporte (SMSI - Strong Metal-Support Interaction) e o rearranjo atômico nas nanopartículas bimetálicas expostas a atmosferas gasosas. Este trabalho apresenta os resultados de um estudo sobre o comportamento de nanopartículas (NPs) de CuNi1-/CeO2 (0<<1) durante o tratamento de redução em H2 (etapa usada na ativação de catalisadores) seguido da reação inversa de deslocamento gás-água (RWGS - Reverse Water-Gas Shift). As amostras foram inicialmente caracterizadas em termos de suas composições, componentes químicas, arranjo atômico e tamanhos usando as técnicas de espectroscopia de raios X por dispersão em energia (EDS - Energy Dispersive X-ray Spectroscopy), espectroscopia de fotoelétrons excitados por raios X (XPS - X-ray Photoelectron Spectroscopy) e microscopia eletrônica de transmissão (TEM - Transmission Electron Microscopy). Após, as amostras foram aquecidas até 500 ∘C em uma atmosfera de H2. Em 500 ∘C as amostras foram expostas às atmosferas de H2 e H2+CO2. Durante todos esses tratamentos, as amostras foram caracterizadas in situ pelas técnicas de XPS em pressões próximas à ambiente (NAP-XPS - Near Ambient Pressure X-ray Photoelectron Spectroscopy) com energias de fótons incidentes de 1250 eV e 2000 eV, espectroscopia de absorção de raios X (XAS - X-ray Absorption Spectroscopy) e XAS resolvido no tempo medido no modo transmissão nas bordas K do Cu (8979 eV), K do Ni (8333 eV) e L3 do Ce (5723 eV). As medidas in situ realizadas mostraram uma migração de átomos de Cu (Ni) para a superfície das nanopartículas durante o tratamento em atmosfera de H2 (H2+CO2). Além disso, a população atômica de Cu na superfície é dependente da quantidade de Cu usada no processo de síntese. Uma maior concentração de Cu durante a síntese implica em uma menor população de Cu na superfície durante as reações de redução em H2 e de RWGS. A ocorrência do fator geométrico do efeito SMSI, caracterizado por uma camada de óxido de cério em torno das nanopartículas durante o tratamento de redução, foi observado para algumas nanopartículas, revelando a existência de um limite na concentração de Cu para a ocorrência do efeito. Somente as nanopartículas com grande quantidade de Cu apresentaram o efeito SMSI durante o tratamento de redução em H2. A superfície das nanopartículas apresentando o efeito SMSI retorna ao estado inicial (sem a camada de óxido de cério) após a inserção da atmosfera de CO2. Além disso, a natureza do efeito SMSI foi elucidada pela primeira vez: a camada de óxido de cério interage com os átomos de Cu e Ni através dos estados iniciais Ce3d10O2p6Ce4f0 e Ce3d10O2p6Ce4f1, dependendo do caso estudado. Como consequência do efeito SMSI, os átomos de Cu das nanopartículas reduzem antes (temperaturas mais baixas) do que nanopartículas semelhantes que não apresentam o efeito SMSI. Os resultados de reatividade para a formação de CO através da reação RWGS, associados aos eventos catalíticos a nível atômico observados (efeito SMSI, população atômica de superfície, mudança no estado de oxidação dos catalisadores) levaram à projeção de um catalisador otimizado aplicado à reação RWGS. A camada de óxido de cério do efeito SMSI tem consequência negativa nos resultados de reatividade. A migração de átomos de Ni para a superfície levou a uma diminuição da reatividade catalítica na reação RWGS. Baseado nesses resultados, é proposta a síntese de nanopartículas com uma grande quantidade de Ni visando evitar a ocorrência do efeito SMSI e permitir uma grande população atômica de Cu na superfície durante a reação RWGS, ambos desempenhando um papel fundamental nos resultados de reatividade para a reação RWGS.<br>The CO2 molecule is the main responsible for the negative consequences of the greenhouse effect. The increasing numbers associated to the amount of CO2 emission in the atmosphere have attracted the attention of scientists aiming the discovery of new catalysts to CO2 dissociation reactions. At the same time, several atomic events may influence the catalytic properties of such systems, like the Strong Metal-Support Interaction (SMSI) effect and atomic rearrangement when the bimetallic nanoparticles (NPs) are exposed to a gaseous atmosphere. This work presents the results of a study about the behavior of CuNi1-/CeO2 (0<<1) NPs during the H2 reduction treatment (step used in the activation of the catalysts) followed by the reverse water-gas shift (RWGS) reaction. The samples were initially characterized in terms of their compositions, chemical components, atomic arrangement and sizes, using the Energy Dispersive X-ray Spectroscopy (EDS), X-Ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM) techniques. Afterwards, these samples were heated to 500 ∘C in a H2 atmosphere. At 500 ∘C the samples were exposed to H2 and H2+CO2 atmospheres. During all these treatments, the samples were characterized in situ by Near Ambient Pressure XPS (NAP-XPS) with incident photon energies of 1250 eV and 2000 eV, X-ray Absorption Spectroscopy (XAS) and time-resolved XAS techniques in transmission mode at the Cu K (8979 eV), Ni K (8333 eV) and Ce L3 (5723 eV) edges. The in situ measurements performed showed a copper (nickel) migration to the nanoparticles surface during H2 (H2+CO2) gaseous treatment. Moreover, the Cu surface atomic population is dependent on the Cu amount used in the synthesis process. The higher concentration of Cu during the synthesis implies in a smaller Cu surface atomic population during H2 reduction and RWGS reaction. The occurrence of the geometrical factor of the SMSI effect, characterized by a cerium oxide capping layer surrounding the nanoparticles during reduction treatment, was observed for some of the NPs, revealing the existence of a threshold in the Cu concentration to occur the SMSI effect. Only nanoparticles with high amounts of Cu present the SMSI effect during the H2 reduction treatment. The surface of the nanoparticles presenting the SMSI effect is recovered to the initial state (free of the capping layer) after inserting the CO2 atmosphere. Moreover, the nature of the SMSI effect was elucidated for the first time: the capping layer interacts with the Cu and Ni atoms via Ce3d10O2p6Ce4f0 and Ce3d10O2p6Ce4f1 initial states, depending on the case studied. As a consequence of the SMSI effect, the Cu atoms of the nanoparticles reduce earlier (lower temperature) than similar nanoparticles that do not present the SMSI effect. The reactivity results towards the CO formation in the RWGS reaction, associated to the catalytic events at atomic level observed (SMSI effect, surface atomic population, change on the oxidation state of the catalysts) led to the design of an optimized catalyst applied to this reaction. The capping layer of the SMSI effect has a negative influence on the reactivity results. The migration of Ni atoms to the surface led to a decrease of the catalyst reactivity in the RWGS reaction. Based on these results, it is proposed a synthesis of nanoparticles with a high amount of Ni in order to avoid the SMSI effect and to allow a high Cu surface atomic population during the RWGS reaction, both playing a key role in the reactivity results towards the RWGS reaction.
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Guler, Mehmet. "Evaluation Of State Owned Indigenous Coal Fired Power Plants Including Coal Reserves." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611591/index.pdf.
Full textAbstract:
Fossil fuels has preserved their importance in gradually increasing production and consumption of both energy and electricity of the world. Asia, especially China and India, has arisen new actors of the sector.
Energy and electricity consumption of Turkey has also increased in parallel with her economic development, but due to her limited resources, she has become more and more energy dependent in order to meet her growing demand.
Although hard coal is only found around Zonguldak region, with its abundant and widely spread reserves, Turkey ranked world&rsquo<br>s third place in lignite production in 2008. Having low calorific value together with high ash and moisture content, most of lignites extracted is being consumed in thermic power plants located near those reserves.
In the first two chapters of this study, energy in the world and Turkey will be considered seperately, then coal resources in Turkey will be analysed in the next coming chapter. Indirect and direct greenhouse emissions presented to the UNFCCC will be handled in the fifth chapter
In the last chapter, first past and present performances of all indigenous coal fired power plants will be analysed, then after projecting their generation and fuel needs, they are evaluated considering with the reserves they are located. Finally, at the end of decomissioning of those power plants, remaining reserves will be re-evaluated and additional new units will be proposed accordingly.