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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

The interaction between water movement, diffusion boundary layers, phosphate uptake and phosphate limited growth of Ulva australis / Patrick William Hone

Hone, Patrick William January 1988 (has links)
Bibliography: leaves 151-184 / vi, 184 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Botany, 1990
22

Remoção de césio e amerício utilizando fibra de coco para a aplicação no tratamento de rejeitos radioativos / Removal of cesium e americium using coconut fiber application for the treatment of radioactive wastes

JESUS, NELLA N.M. de 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:42:25Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:08Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
23

Remoção de césio e amerício utilizando fibra de coco para a aplicação no tratamento de rejeitos radioativos / Removal of cesium e americium using coconut fiber application for the treatment of radioactive wastes

JESUS, NELLA N.M. de 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:42:25Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:08Z (GMT). No. of bitstreams: 0 / A fibra de coco tem sido usada como um adsorvente alternativo e de baixo custo na remoção de diversos metais pesados. A biossorção é um processo que tem alcançado grande importância nas últimas décadas no tratamento de efluentes e de rejeitos radioativos. Este estudo apresenta a eficiência de remoção dos íons 133Cs e 241Am de soluções aquosas utilizando-se a biomassa bruta e ativada. Os estudos foram realizados em batelada e os parâmetros analisados foram: os efeitos do pH e da concentração da solução, tamanho de partícula do biomassa e tempo de contato. Os modelos de isotermas de Langmuir e Freundlich foram aplicados, bem como os modelos cinéticos de ordem de reação. A cinética que melhor representa o processo de adsorção dos íons estudados foi o modelo de pseudo-segunda ordem. O modelo de isotermas que se ajusta ao processo de adsorção do 133Cs e do 241Am é o de Freundlich. Verificou-se também que a melhor condição de remoção para o 241Am foi de cerca de 94% a partir de 30 minutos tanto para a biomassa bruta quanto para a ativada ao passo que o 133Cs foi de 75% a partir de 40 minutos com a biomassa ativada. Os resultados indicaram que a fibra de coco pode ser uma alternativa de tratamento de rejeitos radioativos líquidos que contenham, em sua composição, estes radionuclídeos. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
24

Estudo da OtimizaÃÃo do Processo H2O2/UV para degradaÃÃo do Corante Remazol Vermelho RB 133% / Study of the Process Optimization H2O2/UV for degradation of the dye Remazol Red RB 133%

Jefferson Pereira Ribeiro 25 May 2011 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / As atividades industriais que consomem excesso de Ãgua no seu processo industrial, geralmente geram um elevado volume de efluentes, onde a indÃstria tÃxtil à um exemplo tÃpico. A oxidaÃÃo quÃmica à um dos processos alternativos para o tratamento de efluentes contendo corantes tÃxteis, entre eles destacam-se os POAs que sÃo baseados na geraÃÃo de radicais hidroxilas (.OH) no qual sÃo altamente oxidantes, podendo decompor compostos de maneira rÃpida e nÃo-seletiva, conduzindo a mineralizaÃÃo parcial ou completa do contaminante. O presente trabalho estudou o uso de processo oxidativo avanÃado para a degradaÃÃo do corante Remazol Vermelho RB 133%. Os estudos foram realizados em duas etapas. Na primeira etapa, no reator com 710 mL de volume Ãtil, foram realizados estudos de otimizaÃÃo dos parÃmetros: cinÃtica de descoloraÃÃo, dosagem do perÃxido de hidrogÃnio, pH, temperatura, adiÃÃo de perÃxido de hidrogÃnio em linha. A cinÃtica de descoloraÃÃo, e o efeito inibitÃrio de Ãnions tambÃm foram estudados. O estudo de cinÃtica mostrou que em 250 minutos houve uma descoloraÃÃo completa da soluÃÃo usando uma dosagem de perÃxido de hidrogÃnio de 1% H2O2 mediante o uso da radiaÃÃo UV. Nestas condiÃÃes houve uma remoÃÃo de 78,41% na DQO. O pH nÃo influenciou no processo de descoloraÃÃo da soluÃÃo, em contraste, para valores de pH iniciais 8 e 10 houve uma maior remoÃÃo na DQO. O estudo do efeito da temperatura do sistema mostrou que com o aumento temperatura a velocidade de descoloraÃÃo à pouco influenciada, ao passo que o aumento da temperatura (80ÂC) diminuiu a eficiÃncia do processo de remoÃÃo da DQO. A adiÃÃo de H2O2 em linha do processo aumentou a eficiÃncia na remoÃÃo de DQO. Os resultados das eficiÃncias de remoÃÃo ao final do processo indicaram que nÃo houve diferenÃa entre os tratamentos na presenÃa dos Ãnions na concentraÃÃo estudada (10 mM) quando comparada a degradaÃÃo sem a presenÃa desses Ãnions, pois ao final de todos os tratamentos a soluÃÃo ficou incolor. Na segunda etapa, no reator com 520 mL de volume Ãtil, foram realizados estudos de vazÃo e potÃncia de radiaÃÃo UV. O estudo mostrou que para as vazÃes estudadas 1,0; 2,0 e 3,0 L/min nÃo houve uma X diferenÃa significativa no processo de descoloraÃÃo. As concentraÃÃes da matÃria orgÃnica ao final de 480 minutos de experimento para as trÃs vazÃes foram 36,63%; 51,08% e 48,35%, respectivamente. O aumento da potÃncia de radiaÃÃo UV proporcionou um aumento na eficiÃncia do processo de descoloraÃÃo e degradaÃÃo da matÃria orgÃnica. O estudo com efluente real mostrou uma baixa eficiÃncia na reduÃÃo de cor e de demanda quÃmica de oxigÃnio. / Industrial processes that consume excess of water, typically generates a high volume of effluent, where the textile industry is a typical example. The oxidation chemistry is one of the alternative processes for the textile dyes treatment. In this context, the Advanced Oxidation Processes (AOPs) are based on the generation of hydroxyl radicals (.OH) on which are highly oxidizing compounds can decompose quickly and non-selective contaminant solutes, for a partial or complete mineralization. This study investigated the use of advanced oxidation process for degradation of the dye Remazol Red RB 133%. The studies were conducted in two stages. For first step, in the reactor with 710 mL of working volume , were studies the parameters: kinetic effect, hydrogen peroxide dosage, temperature, pH, addition of hydrogen peroxide in the line. The kinetics study decolorization and the inhibitory effect of anions were also studied. The study of kinetic showed that in 250 minutes there was a complete decolorization of the solution using a H2O2 dose of 1% (v/v) through the use of UV radiation, and a 78.41% removal in Chemical Oxygen Demand (COD) was observed. The pH effect not influenced in the decolorization process; however has been influenced in removal of COD. The study of temperature effect showed that for an increase in temperature the decolorization rate increases, but a small improvement in the efficiency of COD removal. The addition of H2O2 during the process increased the efficiency of COD removal. The results of the efficiencies of the end of the process indicated that there was no difference between treatments in the presence of anions in the studied concentration (10 mM) when compared to degradation without the presence of these anions, since the end of all treatments, the solution was colorless. In the second stage, was carried in the reactor with 520 mL of working volume flow studies were performed and power of UV radiation. The studies of flow rate showed that for flow rate of 1.0; 2.0 and 3.0 L/min there was no significant difference in the process decolorization process. The of organic matter concentrations at 480 minutes of experiment for the three flow rates were 36.63%, 51.08% and 48.35% respectively. The increased power of UV radiation caused an increase in the XII efficiency of discolouration and degradation of organic matter. The study showed a real effluent with low efficiency to reduce color and chemical oxygen demand.
25

Identification des leptons taus dans l'expérience D0 auprès du Tevatron et recherche de particules supersymétriques se désintégrant avec R_parité violée (couplage $\lambda_{133}$)

Le Bihan, Anne-Catherine 19 April 2005 (has links) (PDF)
Le sujet de cette thèse est la recherche de particules supersymétriques dans l'expérience D0 auprès de l'accélérateur du Tevatron où se produisent des collisions protons-antiprotons à une énergie $\sqrt{s}=1.96 TeV dans le centre de masse. De nombreux argument plaident en faveur du fait que le Modèle Standard malgré ses nombreux succès ne serait qu'une théorie effective décrivant les interactions à basse énergie entre les particules élémentaires. Le Tevatron étant à l'heure actuelle le collisionneur le plus énergétique au monde permet de rechercher les particules supersymétriques non découvertes à ce jour. L'analyse a porté sur un échantillon de données correspondant à une luminosité intégrée de 352 pb$ç{-1}$ (2001-2004). Le modèle supersymétrique retenu est celui où la R-partité est non-conservée par couplage $\lambda_133}$. L'état final peut être caractérisé par la présence de deux électrons, d'énergie transverse manquante et d'au moins un tau se désintégrant de façon hadronique. Aucun excès d'événéments avec une telle signature n'ayant été identifié, de nouvelles limites inférieures sur les masses des neutralinos et charginos ont été obtenues. Afin de pouvoir mener cette analyse à bien nous avons au préalable développé une méthode d'identification des leptons taus dans leurs modes hadroniques. Cette méthode s'appuie sur des réseaux de neurones et utilise les informations du calorimètre et du trajectographe ayant trait à l'isolation et aux dépôts énergétiques longitudinaux et transverses des taus. L'efficacité et la validité de cette méthode ont été estimées dans les données à l'aide du processus Z $\rightarrow \tau \tau \rightarrow \mu \tau _hadr}$. Cette méthode d'identification à l'aide de réseaux de neurones permet de rejeter l'important bruit de fond des jets QCD d'un facteur 100 pour environ 50% d'efficacité. Elle est à l'heure actuelle un outil officiel de l'expérience D0.
26

Strategic Entry Decisions, Accounting Signals, and Risk Management Disclosure

Zou, Youli 14 January 2014 (has links)
This dissertation investigates the economic consequences from hedge accounting signals and risk management disclosure. I first examine the product market consequences to these accounting signals and related disclosure in Chapter 1, then stock market reactions to disclosure requirements in Chapter 2. Chapter 1 examines potential entrants’ strategic entry decisions in response to incumbents’ accounting information and related disclosure. I predict that potential entrants are more likely to enter markets in which the incumbents’ accounting information suggests higher future production costs that are specific to the incumbents themselves. I further hypothesize that the relation is stronger when the accounting signals are accompanied by more disclosure. Using detailed U.S. airline industry data and hedge accounting disclosure under SFAS 133, I find that potential entrants are more likely to enter routes in which the incumbents’ lower accumulated other comprehensive income from fuel hedges suggests their higher future production costs. This entry pattern is stronger when incumbents have more transparent annual report disclosure regarding their fuel hedge programs. The entry pattern is also stronger after a systematic increase in risk management disclosure requirements following the (exogenous) adoption of SFAS 161. Chapter 2 analyzes stock returns of U.S. airlines around events leading up to the adoption of SFAS 161. SFAS 161 enhanced the disclosure requirements for derivatives and hedging activities. I find that U.S. airlines experienced statistically significant positive returns around the key events leading up to the adoption of SFAS 161. I then examine the cross-sectional variation of the returns around these events. Regression results provide initial support for the real effects theory that greater disclosure requirements could distort firms’ hedging and production decisions and lead to suboptimal behavior. In summary, this dissertation provides evidence that competitors use hedge accounting signals and related disclosure in making product market decisions. Meanwhile, additional risk-management disclosures may also distort firms’ hedging and production behavior, leading to suboptimal decisions. This dissertation sheds light on the ongoing projects by the FASB and the IASB on hedge accounting and disclosure and informs the regulators that costs and benefits should be weighted in hedge accounting policy setting.
27

Strategic Entry Decisions, Accounting Signals, and Risk Management Disclosure

Zou, Youli 14 January 2014 (has links)
This dissertation investigates the economic consequences from hedge accounting signals and risk management disclosure. I first examine the product market consequences to these accounting signals and related disclosure in Chapter 1, then stock market reactions to disclosure requirements in Chapter 2. Chapter 1 examines potential entrants’ strategic entry decisions in response to incumbents’ accounting information and related disclosure. I predict that potential entrants are more likely to enter markets in which the incumbents’ accounting information suggests higher future production costs that are specific to the incumbents themselves. I further hypothesize that the relation is stronger when the accounting signals are accompanied by more disclosure. Using detailed U.S. airline industry data and hedge accounting disclosure under SFAS 133, I find that potential entrants are more likely to enter routes in which the incumbents’ lower accumulated other comprehensive income from fuel hedges suggests their higher future production costs. This entry pattern is stronger when incumbents have more transparent annual report disclosure regarding their fuel hedge programs. The entry pattern is also stronger after a systematic increase in risk management disclosure requirements following the (exogenous) adoption of SFAS 161. Chapter 2 analyzes stock returns of U.S. airlines around events leading up to the adoption of SFAS 161. SFAS 161 enhanced the disclosure requirements for derivatives and hedging activities. I find that U.S. airlines experienced statistically significant positive returns around the key events leading up to the adoption of SFAS 161. I then examine the cross-sectional variation of the returns around these events. Regression results provide initial support for the real effects theory that greater disclosure requirements could distort firms’ hedging and production decisions and lead to suboptimal behavior. In summary, this dissertation provides evidence that competitors use hedge accounting signals and related disclosure in making product market decisions. Meanwhile, additional risk-management disclosures may also distort firms’ hedging and production behavior, leading to suboptimal decisions. This dissertation sheds light on the ongoing projects by the FASB and the IASB on hedge accounting and disclosure and informs the regulators that costs and benefits should be weighted in hedge accounting policy setting.
28

Functional relevance of naturally occurring mutations in adhesion G protein-coupled receptor ADGRD1 (GPR133)

Fischer, Liane, Wilde, Caroline, Schöneberg, Torsten, Liebscher, Ines 18 August 2016 (has links) (PDF)
Background: A large number of human inherited and acquired diseases and phenotypes are caused by mutations in G protein-coupled receptors (GPCR). Genome-wide association studies (GWAS) have shown that variations in the ADGRD1 (GPR133) locus are linked with differences in metabolism, human height and heart frequency. ADGRD1 is a Gs protein-coupled receptor belonging to the class of adhesion GPCRs. Results: Analysis of more than 1000 sequenced human genomes revealed approximately 9000 single nucleotide polymorphisms (SNPs) in the human ADGRD1 as listed in public data bases. Approximately 2.4 % of these SNPs are located in exons resulting in 129 non-synonymous SNPs (nsSNPs) at 119 positions of ADGRD1. However, the functional relevance of those variants is unknown. In-depth characterization of these amino acid changes revealed several nsSNPs (A448D, Q600stop, C632fs [frame shift], A761E, N795K) causing full or partial loss of receptor function, while one nsSNP (F383S) significantly increased basal activity of ADGRD1. Conclusion: Our results show that a broad spectrum of functionally relevant ADGRD1 variants is present in the human population which may cause clinically relevant phenotypes, while being compatible with life when heterozygous.
29

Three essays on competition and innovation

Nepelski, Daniel 12 February 2010 (has links)
Informations- und Kommunikationstechnologien (IKT) sind der Antrieb des modernen Innovationsprozesses. Für besseres Verständnis dieser Dynamik, analysiert diese Dissertation die Wechselwirkungen zwischen Innovation und Wettbewerb. Die Arbeit umfasst zwei Teile: Erstens wird die Frage behandelt, wie die Märkte organisiert werden können, um das optimale Marktergebnis zu erreichen. Zweitens werden die Rückwirkungen der innovativen Tätigkeit auf Wettbewerb und auf Organisation der wirtschaftlichen Tätigkeit analysiert. Betrachtet man den Einfluss von Wettbewerb auf Innovation, zeigt eine empirische Analyse, dass IKT-getriebene Innovationen in konzentrierten Industrien vorherrschen. Im Gegensatz dazu gedeihen Innovationen, die auf anderen Technologien basieren, in eher vollkommenen Märkten. Der Vergleich suggeriert, dass die IKT-getriebene Innovationen andere Charakteristika aufweisen als Innovationen, die auf anderen Technologien basieren. Betrachtet man die Rückwirkung von Innovation auf Wettbewerb, sind zwei Ergebnisse wert genannt zu werden. Erstens, obwohl profitabel von der Perspektive einzelner Unternehmen aus, sinkt der Industrieprofit, wenn eine produktvielfalt-steigernde Technologie durch alle Firmen übernommen wird. Des Weiteren sind die Entscheidungen der Unternehmen in Bezug auf die Technologieadoption nicht immer optimal aus Sicht der sozialen Wohlstandsmaximierung. Zweitens in Bezug auf Organisation der wirtschaftlichen Tätigkeit wird gezeigt, dass IKT sowohl zu mehr Wettbewerb als auch zu der Entstehung von hybriden Organisationsformen führen kann, was von den jeweiligen Charakteristika der Unternehmen abhängt. Obwohl diese Dissertation nur ein kleines Stück der Komplexität analysiert, wirft sie ein neues Licht auf die Zusammenhänge von Marktesstruktur und Innovation und ihre gegenseitigen Rückwirkungen. Interessanterweise sind die Ergebnisse weit entfernt von gewohnten Sichtweisen und in vielen Fällen entgegen der intuitiven Ausgangserwartung. / Information and communication technologies (ICT) are driving the modern innovation process. To better understand these dynamics, the current dissertation analyses the interactions between innovation and competition. The scope of this work can be divided into two areas: The first one deals with a question of how markets could be organized to produce the most optimal outcome. The second one analyses the feedback effects of innovative activity on competition and the organisation of economic activity. Regarding the impact of competition on innovation, an empirical analysis reveals that ICT- driven innovations dominate in concentrated industries, whereas innovations based on other technologies flourish in moderately competitive markets. This suggests that there are some features that make ICT-enabled innovations exceptional, compared to innovations based on other technologies. Concerning the impact of innovation, two findings are worth emphasising. First, as shown in a theoretical analysis, although profitable from an individual producer’s perspective, the adoption of a technology increasing product variety across the entire industry erodes firms’ payoffs. In addition, firms'' decisions with respect to the technology adoption are not always efficient from the social welfare point of view. Second, another empirical analysis included in this work reveals that ICT leads to more competition and facilitates the emergence of hybrid organization forms, subject to firm''s and industry''s characteristics. Although this dissertation reveals only a small piece of the complexity of the ICT-driven innovation process, it casts some new light on the importance of market structure for ICT- enabled innovation and the feedback effect of the technology on firms’ environment. Interestingly, the outcomes of this thesis show that these interactions are often far from straightforward and in many cases counterintuitive.
30

Three essays in competition economics

Guo, Dongyu 18 November 2015 (has links)
Die Dissertation handelt über Wettbewerbsökonomie. Kapitel 1 betrachtet eine Fusion zwischen zwei regulierten Firmen, die in getrennten Märkten agieren und jeweils mit unregulierten Firmen konkurrieren. Die optimale Fusionspolitik für regulierte Firmen hängt von der Intensität des Wettbewerbs zwischen den unregulierten Firmen ab, verschärfter Wettbewerb zwischen den unregulierten Firmen induziert eine mildere Fusionspolitik. Das Gegenteil gilt, wenn die regulierten Firmen in ein wettbewerbsfähiges Marktsegment expandieren und die regulierten und unregulierten Waren komplementär sind. Kapitel 2 untersucht die optimale Fusionspolitik zwischen zwei wettbewerbsfähigen Firmen. Unter den strukturellen Auflagen, die sich am effektivsten herausgestellt haben um einen wirksamen Wettbewerb wiederherzustellen, gibt es eine die sich stark hervorhebt, nämlich die Veräußerung von differenzierten Marken an andere Wettbewerber. Dies ist eine effektive Möglichkeit, um die Marktmacht der neuen Firma zu verringern und sie kann die Möglichkeiten für privat und sozial wünschenswerte Fusionen erhöhen. Vor allem wenn die Güter annähernd perfekt substituierbar sind, ist der Bereich der Effizienzgewinne, die eine Fusion unter Auflagen erlauben, größer. Kapitel 3 untersucht die allgemein etablierte Feststellung, dass Einzelhandelspreise sich schneller anpassen, wenn Input Preise steigen, als wenn sie fallen. Durch die Anwendung eines dynamischen zwei Perioden Preiswettbewerb Modells zeigt sich das Folgende für die Angebotsseite für asymmetrische Preisanpassung: die Existenz von profitablen Lagerungsmöglichkeiten ermöglicht es wettbewerbsfähigen Firmen sich glaubhaft zu verpflichten, ihre Preise umgehend über die marginalen Kosten zu setzen, wenn sie höhere Input Preise antizipieren. Dies lockert den Wettbewerb sodass Firmen positive Gewinne erzielen. Wenn erwartet wird das Input Preise sinken, landen die Firmen im Bertrand Paradoxon und die Preisanpassung erfolgt langsamer. / This thesis is about competition economics. Chapter 1 considers a merger between two regulated firms operating in two separate markets, and in each market there are unregulated competitors. The optimal merger policy for regulated firms depends on the intensity of competition between unregulated firms, fiercer competition between unregulated firms induces a more lenient merger policy. These results are reversed if the regulated firms expand into a competitive segment of the market and the regulated and unregulated goods are complements. Chapter 2 studies the optimal merger policy between two competitive firms. Among the structural remedies which have being treated as the most effective manners to restore effective competition, there is one relevant type, namely, the divestiture of differentiated brands to other competitor(s). It is a powerful tool to lessen the merged entity''s market power and can increase the scope for privately and socially desirable mergers. In particular, when goods are closer to perfect substitutability, the range of the efficiency gains which allows the merger with remedies to be approved is larger. Chapter 3 investigates the well-established observation that retail prices adjust faster when input costs rise than when they fall. From the supply side to asymmetric price adjustments, using a model of two-period dynamic price competition, it shows that the presence of profitable storing allows competitive firms to credibly commit to immediately increase their prices above current marginal costs when they anticipate higher input costs. This relaxes competition and firms earn positive profits. If input costs are expected to decline, the firms are trapped in the Bertrand paradox and price adjustment is slower.

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