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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

Mining Software Repositories to Support Software Evolution

Kagdi, Huzefa H. 15 July 2008 (has links)
No description available.
22

Modelagem e otimização de misturas ternárias de polipropileno (PP), borracha de etileno-propileno-dieno (EPDM) e pó de pneu (SRT). / Modeling and optimization of polypropylene (PP), ethylene-propylene-diene rubber (EPDM) and scrap rubber tire (SRT) ternary mixtures

Wilson Souza da Silva 29 April 2011 (has links)
O aumento nos rejeitos industriais e a contínua produção de resíduos causam muitas preocupações no âmbito ambiental. Neste contexto, o descarte de pneus usados tem se tornado um grande problema por conta da pequena atenção que se dá à sua destinação final. Assim sendo, essa pesquisa propõe a produção de uma mistura polimérica com polipropileno (PP), a borracha de etileno-propileno-dieno (EPDM) e o pó de pneu (SRT). A Metodologia de Superfície de Resposta (MSR), coleção de técnicas estatísticas e matemáticas úteis para desenvolver, melhorar e optimizar processos, foi aplicada à investigação das misturas ternárias. Após o processamento adequado em extrusora de dupla rosca e a moldagem por injeção, as propriedades mecânicas de resistência à tração e resistência ao impacto foram determinadas e utilizadas como variáveis resposta. Ao mesmo tempo, a microscopia eletrônica de varredura (MEV) foi usada para a investigação da morfologia das diferentes misturas e melhor interpretação dos resultados. Com as ferramentas estatísticas específicas e um número mínimo de experimentos foi possível o desenvolvimento de modelos de superfícies de resposta e a otimização das concentrações dos diferentes componentes da mistura em função do desempenho mecânico e além disso com a modificação da granulometria conseguimos um aumento ainda mais significativo deste desempenho mecânico. / The increase in industrial waste and solid waste production cause many concerns in the environment. In this context, the disposal of used tires has become a major problem because of the little attention given to their final destination. Therefore, this research proposes the production of a polymer blend of polypropylene (PP), rubber of ethylene-propylene-diene (EPDM) and tire dust (SRT). The Response Surface Methodology (RSM), a collection of mathematical and statistical techniques useful for developing, improving and optimizing processes, was applied to the investigation of ternary mixtures. After proper processing on twin screw extrusion and injection molding, the mechanical properties of tensile and impact strength were determined and used as response variables. At the same time, scanning electron microscopy (SEM) was used to investigate the morphology of different blends and better interpretation of results. With specific statistical tools and a minimum number of experiments it was possible to develop models of response surfaces and the optimization of the concentrations of different components of the mixture depending on the mechanical performance and even with the change in particle size could increase even more significant this mechanical performance.
23

Criblage antibactérien par une chimiothèque de molécules - Recherche d'inhibiteurs de deux systèmes d'efflux chez Staphylococcus aureus : les pompes NorA et Msr(A)

Marquez-Garrido, Béatrice 28 September 2005 (has links)
Face à l'émergence de bactéries multi-résistantes aux antibiotiques, il est nécessaire de trouver de nouvelles molécules, actives contre les bactéries, ou qui inhibent leurs mécanismes de résistance et restaurent ainsi l'activité des antibiotiques existants. Dans ce contexte, nous avons mis en place un système de criblage robotisé à moyen débit permettant d'étudier l'activité de molécules sur des bactéries en milieu liquide. Les composés testés sont des molécules synthétiques, provenant de la Chimiothèque nationale du CNRS, et des extraits naturels de plantes. La collection de bactéries utilisée se compose de souches sensibles et de nombreuses souches résistantes. Dans le cadre de cette étude, nous nous sommes intéressés à la résistance par mécanisme d'efflux actif. Nous avons étudié en particulier deux systèmes d'efflux chez Staphylococcus aureus: la pompe NorA, qui confère une résistance multiple aux antibiotiques, dont les fluoroquinolones, et la pompe Msr(A), qui est spécifique des macrolides. Un premier criblage sur les souches sensibles (Escherichia coli et S. aureus) permet de détecter des molécules ayant une activité antibactérienne. Pour celles-ci, une étude plus approfondie est menée. Les molécules dépourvues d'activité antibactérienne sont ensuite testées sur les deux souches de S. aureus résistantes par efflux, pour déceler une potentielle activité d'inhibiteur de pompe. Cette activité est alors confirmée par des expériences d'accumulation de l'antibiotique. Au cours de cette étude, une nouvelle série de molécules présentant une bonne activité antibactérienne vis-à-vis des deux souches sensibles a été mise en évidence. Des résultats préliminaires indiquent que ces molécules inhibent la synthèse des protéines. Le criblage réalisé vis-à-vis de la pompe d'efflux NorA a mis en évidence trois familles de molécules actives, dont on a vérifié qu'elles permettent de restaurer l'activité de plusieurs antibiotiques efflués par la pompe. Un criblage similaire réalisé sur la protéine Msr(A) a révélé quelques touches qui montrent une synergie avec l'antibiotique efflué; leur activité sur l'accumulation de l'antibiotique doit être vérifiée. Par ailleurs, un modèle tridimensionnel de la protéine Msr(A) a été établi, par homologie avec les pompes cristallisées de la même famille (protéines à ATP-Binding Cassette). Ce modèle est en cours de validation.
24

Interactions between carbon and power markets in transition

Richstein, Jörn Constantin January 2015 (has links)
In this research, several improvements to the European Union Emissions Trading System (EU ETS) were analysed. The EU ETS is a market for emission allowances and the European Union's main instrument for reducing greenhouse gas emissions (of which CO2 is the main component). However, the CO2 allowance price in this market has been highly volatile and generally too low to stimulate significant long-term reductions in CO2 emissions. National and system-wide price floors and ceilings were investigated, prompted by the UK’s implementation of a CO2 price floor through a supplementary CO2 tax. The effects of the "backloading" of CO2 allowances and the proposed Market Stability Reserve were also investigated. While the latter measures may increase dynamic efficiency, this research showed that a well-designed price corridor is even more efficient, while still achieving the long-term abatement targets and stabilising prices. Furthermore, different methods for adjusting the CO2 emissions cap in response to changes in renewable energy policies were investigated. Finally, the impact of investors' risk aversion on the functioning of the CO2 market was evaluated. The analyses were conducted with the use of EMLab-Generation, an agent-based model that simulates two interconnected electricity markets with a joint CO2 emissions trading system. In this model, the companies have limited knowledge about the future, which makes it possible to investigate the impact of public policy instruments on long-term investment dynamics. / <p>The Doctoral Degrees issued upon completion of the programme are issued by Comillas Pontifical University, Delft University of Technology and KTH Royal Institute of Technology. The invested degrees are official in Spain, the Netherlands and Sweden, respectively.</p><p>copyright notice:(c) 2015 Richstein, J.C. · Creative Commons Attribution-Non- Commercial-NoDerivatives 4.0 International License</p><p>QC 20151109</p>
25

Études préliminaires de sûreté du réacteur à sels fondus MSFR. / Safety studies dedicated to molten salt reactors with a fast neutron spectrum and operated in the Thorium fuel cycle – Innovative concept of Molten Salt Fast Reactor

Brovchenko, Mariya 25 October 2013 (has links)
Les réacteurs nucléaires de 4ème génération devront permettre une utilisation optimisée desressources naturelles. Les travaux réalisés durant cette thèse se placent ainsi dans le cadre del’étude du potentiel de déploiement d’un tel réacteur : le MSFR (Molten Salt Fast Reactor), réacteurà sels fondus à spectre neutronique rapide dans une configuration innovante et encore peuétudiée. Comme un excellent niveau de sûreté est une condition nécessaire pour le déploiementde l’énergie nucléaire, il est important de soulever la question de la sûreté de ce type de réacteurdès les premières phases de sa conception.Le MSFR a fait l’objet d’études comparatives des outils de simulations numériques dans lecadre d’un benchmark neutronique au sein du projet européen EVOL. La définition et l’analysedu benchmark neutronique statique et en évolution ont été réalisées pendant cette thèse. Lescomparaisons des différentes grandeurs physiques ont permis de conclure à un bon accord entreles différents codes et méthodes utilisés par les partenaires du projet, et ont mis en avant l’influencedu choix des bases de données nucléaires. Dans l’objectif de l’étude de sûreté du MSFR,la puissance résiduelle a aussi été étudiée en détails. Un outil de calcul de chaleur résiduellea été développé et validé, permettant ainsi d’évaluer la puissance résiduelle précise du MSFR.Les sources de chaleur de chaque localisation contenant des produits radioactifs ont alors étéquantifiées. Ceci a permis de conclure que le sel combustible et l’unité de bullage constituent lessources majeures de puissance résiduelle.Nous avons initié un travail sur la méthodologie de l’étude de sûreté. Les principes fondamentauxde sûreté sont directement transposables au MSFR, mais leurs applications concrètes nele sont pas. En effet, la spécificité du design, due à l’état liquide du combustible et aux systèmesde retraitement associés au réacteur, ainsi que l’état embryonnaire du design, font qu’un travailpréliminaire de transposition des éléments de sûreté a dû être réalisé. Ce travail a conduit entreautres à dresser une liste d’accidents propres au MSFR. Enfin, nous avons pu mener des étudesphysiques préliminaires sur les conséquences possibles de certains de ces accidents, qui serontutilisées comme base pour des études plus approfondies avec des outils plus sophistiqués. / The nuclear reactors of the 4th generation must allow an optimized use of natural resources,while performing at a high safety level. The framework of this thesis is the deployment study ofone of such a system, an innovative and still little studied Molten Salt Fast Reactor. An excellentsafety is an ultimate requirement of the nuclear energy deployment, so it is important to raisethis question at the current early stage of the MSFR concept development.This concept was the subject of a neutronic tool benchmark within a European projectEVOL. Definition, calculations and results analyses were performed during this thesis. Comparisonsof static neutronic and burn-up calculations, performed by the project participants,concluded to a good agreement between the different codes and methods used and pointed outthe sensibility of the nuclear database choice on the results. With the aim of safety analysis ofthe MSFR, the decay heat was studied in detail. The tool used for the decay heat calculationwas developed and validated, to finally evaluate the decay heat in the reactor. The decay heatsource presented in different zones was quantified, concluding to a high importance of the coolingof the fuel salt and the bubbling system enclosing a part of the fission products.The safety analysis methodology was also studied in this thesis. Even if the safety principlesare directly transposable to the MSFR, the precise recommendations are not. This is due to thespecificity of the design that relies on the liquid state of the fuel, on the reprocessing systemslocated in the reactor and the embryonic stage of the design. First, a preliminary transpositionwork of some criteria to the MSFR design was realized, resulting amongst other things in a listof accidental scenarios particular for MSFR. Finally, a preliminary physical study of some typesof accidental scenarios was performed, that can be used as a basis for further analyses with moresophisticated tools.
26

Modelagem e otimização de misturas ternárias de polipropileno (PP), borracha de etileno-propileno-dieno (EPDM) e pó de pneu (SRT). / Modeling and optimization of polypropylene (PP), ethylene-propylene-diene rubber (EPDM) and scrap rubber tire (SRT) ternary mixtures

Wilson Souza da Silva 29 April 2011 (has links)
O aumento nos rejeitos industriais e a contínua produção de resíduos causam muitas preocupações no âmbito ambiental. Neste contexto, o descarte de pneus usados tem se tornado um grande problema por conta da pequena atenção que se dá à sua destinação final. Assim sendo, essa pesquisa propõe a produção de uma mistura polimérica com polipropileno (PP), a borracha de etileno-propileno-dieno (EPDM) e o pó de pneu (SRT). A Metodologia de Superfície de Resposta (MSR), coleção de técnicas estatísticas e matemáticas úteis para desenvolver, melhorar e optimizar processos, foi aplicada à investigação das misturas ternárias. Após o processamento adequado em extrusora de dupla rosca e a moldagem por injeção, as propriedades mecânicas de resistência à tração e resistência ao impacto foram determinadas e utilizadas como variáveis resposta. Ao mesmo tempo, a microscopia eletrônica de varredura (MEV) foi usada para a investigação da morfologia das diferentes misturas e melhor interpretação dos resultados. Com as ferramentas estatísticas específicas e um número mínimo de experimentos foi possível o desenvolvimento de modelos de superfícies de resposta e a otimização das concentrações dos diferentes componentes da mistura em função do desempenho mecânico e além disso com a modificação da granulometria conseguimos um aumento ainda mais significativo deste desempenho mecânico. / The increase in industrial waste and solid waste production cause many concerns in the environment. In this context, the disposal of used tires has become a major problem because of the little attention given to their final destination. Therefore, this research proposes the production of a polymer blend of polypropylene (PP), rubber of ethylene-propylene-diene (EPDM) and tire dust (SRT). The Response Surface Methodology (RSM), a collection of mathematical and statistical techniques useful for developing, improving and optimizing processes, was applied to the investigation of ternary mixtures. After proper processing on twin screw extrusion and injection molding, the mechanical properties of tensile and impact strength were determined and used as response variables. At the same time, scanning electron microscopy (SEM) was used to investigate the morphology of different blends and better interpretation of results. With specific statistical tools and a minimum number of experiments it was possible to develop models of response surfaces and the optimization of the concentrations of different components of the mixture depending on the mechanical performance and even with the change in particle size could increase even more significant this mechanical performance.
27

Conscious or zombies self-perception in Callithrix jacchus & Dinoponera quadriceps

Polari, Daniel Silva 04 March 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-13T19:54:01Z No. of bitstreams: 1 DanielSilvaPolari_DISSERT.pdf: 1547318 bytes, checksum: 92ebdd280f0c098be7201ceab8cc41b4 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-02-14T21:42:04Z (GMT) No. of bitstreams: 1 DanielSilvaPolari_DISSERT.pdf: 1547318 bytes, checksum: 92ebdd280f0c098be7201ceab8cc41b4 (MD5) / Made available in DSpace on 2017-02-14T21:42:04Z (GMT). No. of bitstreams: 1 DanielSilvaPolari_DISSERT.pdf: 1547318 bytes, checksum: 92ebdd280f0c098be7201ceab8cc41b4 (MD5) Previous issue date: 2016-03-04 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Consci?ncia como fen?meno biol?gico pode consistir de diferentes estados sensoriais, sentimentos e emo??es. Comportamentos especializado, a??es sofisticadas de comunica??o, meta-cogni??o, intera??o social, orienta??o especial, use de mapas mentais para navega??o e mem?ria espaciais, apontam para tipos diferentes de processamentos consciente em g?neros que n?o o Homo. O presente trabalho busca identificar a auto-percep??o em diferentes esp?cies, com testes do espelho em Callithrix jacchus e com testes de auto-localiza??o em Dinoponera quadriceps. O comportamento de C. jacchus no espelho foi catalogado utilizando dois protocolos diferentes: com marca e sem marca. A capacidade de navega??o de D. quadriceps durante o forrageio, foi calculada considerando tr?s diferentes categorias: (1) acesso livre ao ninho/recurso, (2) acesso direto bloqueado por objeto opaco; e 3) bloqueado por objeto transparente. Nossos resultados apontam para auto-percep??o e mambas as esp?cies, com C. jacchus apresentando comportamentos de verifica??o de conting?ncia, auto-observa??o, al?m de utilizar a imagem refletida para observar o ambiente e reagir a marca. D. quadriceps foram capazes de perceber sua pr?pria localiza??o no ambiente e calcular caminhos curtos at? a col?nia ap?s obter o recurso alimentar, em todos os tr?s tipos de testes. Aqui n?s apresentamos evid?ncia de estados conscientes em outras esp?cies que n?o vertebrados. / Consciousness, as a biological phenomenon, may consists of states of feeling, sensation or awareness. Specialized behaviour, sophisticated actions of communication, metacognition, social interaction, spatial orientation, the use of mental maps for navigation, and spatial memory, all point to conscious processing in genus other than Homo. This work aims to identify self-awareness states in two different species: using mirror self-recognition tests in Callithrix jacchus, and using self-perception tests in Dinoponera quadriceps. Displays of C. jacchus self-recognition using a mirror, were appraised with two protocols: no mark and with mark. D.quadriceps navigational capability displays during foraging trips to food resource, were appraised considering three different tests categories: (1) free access, (2) blocked by opaque object; and 3) blocked by clear object. Our results show self-perception in both studied species. With marmosets displaying contingency check behaviour to the specular image, self-observation, environmental exploration using the mirror as a tool and little, but significant mark reactions. Tocandiras were able to perceive its own location and to calculate short return paths to the colony after obtaining the food resource in all three types of tests. Here we provide further evidence of conscious states for species other than vertebrates.
28

Mining Git Repositories : An introduction to repository mining

Carlsson, Emil January 2013 (has links)
When performing an analysis of the evolution of software quality and software metrics,there is a need to get access to as many versions of the source code as possible. There isa lack of research on how data or source code can be extracted from the source controlmanagement system Git. This thesis explores different possibilities to resolve thisproblem. Lately, there has been a boom in usage of the version control system Git. Githubalone hosts about 6,100,000 projects. Some well known projects and organizations thatuse Git are Linux, WordPress, and Facebook. Even with these figures and clients, thereare very few tools able to perform data extraction from Git repositories. A pre-studyshowed that there is a lack of standardization on how to share mining results, and themethods used to obtain them. There are several tools available for older version control systems, such as concurrentversions system (CVS), but few for Git. The examined repository mining applicationsfor Git are either poorly documented; or were built to be very purpose-specific to theproject for which they were designed. This thesis compiles a list of general issues encountered when using repositorymining as a tool for data gathering. A selection of existing repository mining tools wereevaluated towards a set of prerequisite criteria. The end result of this evaluation is thecreation of a new repository mining tool called Doris. This tool also includes a smallcode metrics analysis library to show how it can be extended.
29

Studium chování jaderného reaktoru chlazeného tekutými solemi / Reseach of Molten Salt Cooled Nuclear Reactor Behavior

Kostečka, Jan January 2018 (has links)
The master ‘s thesis deals with the studying behavior of nuclear reactors cooled by liquid salts and with application of liquid salts for IV. Generation of nuclear reactors. For the use of liquid salts, it’s necessary to change the concept of the structure of nuclear reactors. There are new ways to use new fuel in a liquid state. Each salt compound or a set thereof is original in its nature. Therefore, it is necessary to consider a suitable compound for the purposes employed. These points are discussed in the theoretical part. The thesis examines particularly chloride salts, with which there is not much experience. The practical part monitors and verifies the nuclear properties of chloride salts, in our case it is a solid-state chloride sodium chloride’s compound. In addition to the experimental measurement, the MCNP simulation program is used also.
30

Metody pro analýzu vlastností přenosových vedení / Methods for properties analysis of transmission lines

Žůrek, Dalibor January 2012 (has links)
This work focuses on a search of available literature on the theory of transmission lines and verify the possibility of simulation processes on these lines using a suitable simulation program. Initially, for the introduction to the parameters and the phenomenon that characterize the line and are important for understanding the issue. These parameters are then measured and compared with traces from the simulation in program PSpice. In another part of the work, the reader is familiar with the basics of reflectometry and fault detection capabilities on transmission lines with the basic reflectometry methods TDR and FDR, as well as with other methods of OTDR, MSR, and PD-FDR. For the TDR, FDR and MSR methods were made experimental measurements with a view to determining the position of the various types of faults on the tested leadership.

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