• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 1
  • Tagged with
  • 7
  • 7
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
1

Politics Of Renewable Energy Policies In Turkey

Atli, Buket 01 August 2012 (has links) (PDF)
Owing to the unfortunate accidents happened in Fukushima nuclear power plant in Japan on 11th March 2011, renewable energy has again become one of the mostly referred issues in energy related discussions all around the world. Generally, the states are expected to give incentives to the renewable energy sources in order to help the development and spread of those clean energy technologies against the fossil based energy sources. However, the levels of state subsidy to renewable energy sources in Turkey which was announced in 2010 with an Amendment Law was not possible to understand by following the mentioned way of thinking. Unlike other studies in the field of renewable energy policies, the thesis problematizes the role of the states in the formation of renewable energy markets and prefers to use the critical theory while trying to understand how the renewable energy policies in Turkey are formed. The state policies are tried to be understood as a result of historical state and society relations rather than looking for linear reason and result relationships. State is seen not a unified actor but rather a battleground of competing projects each of which arise from a certain way of thinking or in other words, rationalities of government. Consequently, the traces of developmentalism, neoliberalism and neomercantilism are followed starting from the formation of the Turkish electricity market in the late 1990s and the preparation of Renewable Energy Law in 2005 until the aftermath of the recent Amendment to the Renewable Energy Law in 2010.
2

Solidification And Crystallization Behaviour Of Bulk Glass Forming Alloys

Aybar, Sultan 01 September 2007 (has links) (PDF)
The aim of the study was to investigate the crystallization kinetics and solidification behaviour of Fe60Co8Mo5Zr10W2B15 bulk glass forming alloy. The solidification behaviour in near-equilibrium and non-equilibrium cooling conditions was studied. The eutectic and peritectic reactions were found to exist in the solidification sequence of the alloy. The bulk metallic glass formation was achieved by using two methods: quenching from the liquid state and quenching from the semi-state. Scanning electron microscopy, x-ray diffraction and thermal analysis techniques were utilized in the characterization of the samples produced throughout the study. The choice of the starting material and the alloy preparation method was found to be effective in the amorphous phase formation. The critical cooling rate was calculated as 5.35 K/s by using the so-called Barandiaran and Colmenero method which was found to be comparable to the best glass former known to date. The isothermal crystallization kinetics of the alloy was studied at temperatures chosen in the supercooled liquid region and above the first crystallization temperature. The activation energies for glass transition and crystallization events were determined by using different analytical methods such as Kissinger and Ozawa methods. The magnetic properties of the alloy in the annealed, amorphous and as-cast states were characterized by using a vibrating sample magnetometer. The alloy was found to have soft magnetic properties in all states, however the annealed specimen was found to have less magnetic energy loss as compared to the others.
3

Asymptotic properties of the dynamics near stationary solutions for some nonlinear Schrödinger équations

Ortoleva, Cecilia Maria 18 February 2013 (has links) (PDF)
The present thesis is devoted to the investigation of certain aspects of the large time behavior of the solutions of two nonlinear Schrödinger equations in dimension three in some suitable perturbative regimes. The first model consist in a Schrödinger equation with a concentrated nonlinearity obtained considering a {point} (or contact) interaction with strength $alpha$, which consists of a singular perturbation of the Laplacian described by a self adjoint operator $H_{alpha}$, and letting the strength $alpha$ depend on the wave function: $ifrac{du}{dt}= H_alpha u$, $alpha=alpha(u)$.It is well-known that the elements of the domain of a point interaction in three dimensions can be written as the sum of a regular function and a function that exhibits a singularity proportional to $|x - x_0|^{-1}$, where $x_0$is the location of the point interaction. If $q$ is the so-called charge of the domain element $u$, i.e. the coefficient of itssingular part, then, in order to introduce a nonlinearity, we let the strength $alpha$ depend on $u$ according to the law $alpha=-nu|q|^sigma$, with $nu > 0$. This characterizes the model as a focusing NLS with concentrated nonlinearity of power type. In particular, we study orbital and asymptotic stability of standing waves for such a model. We prove the existence of standing waves of the form $u (t)=e^{iomega t}Phi_{omega}$, which are orbitally stable in the range $sigma in (0,1)$, and orbitally unstable for $sigma geq 1.$ Moreover, we show that for $sigma in(0,frac{1}{sqrt 2}) cup left(frac{1}{sqrt{2}}, frac{sqrt{3} +1}{2sqrt{2}} right)$ every standing wave is asymptotically stable, in the following sense. Choosing an initial data close to the stationary state in the energy norm, and belonging to a natural weighted $L^p$ space which allows dispersive stimates, the following resolution holds: $u(t) =e^{iomega_{infty} t +il(t)} Phi_{omega_{infty}}+U_t*psi_{infty} +r_{infty}$, where $U_t$ is the free Schrödinger propagator,$omega_{infty} > 0$ and $psi_{infty}$, $r_{infty} inL^2(R^3)$ with $| r_{infty} |_{L^2} = O(t^{-p}) quadtextrm{as} ;; t right arrow +infty$, $p = frac{5}{4}$,$frac{1}{4}$ depending on $sigma in (0, 1/sqrt{2})$, $sigma in (1/sqrt{2}, 1)$, respectively, and finally $l(t)$ is a logarithmic increasing function that appears when $sigma in (frac{1}{sqrt{2}},sigma^*)$, for a certain $sigma^* in left(frac{1}{sqrt{2}}, frac{sqrt{3} +1}{2sqrt{2}} right]$. Notice that in the present model the admitted nonlinearities for which asymptotic stability of solitons is proved, are subcritical in the sense that it does not give rise to blow up, regardless of the chosen initial data. The second model is the energy critical focusing nonlinear Schrödinger equation $i frac{du}{dt}=-Delta u-|u|^4 u$. In this case we prove, for any $nu$ and $alpha_0$ sufficiently small, the existence of radial finite energy solutions of the form$u(t,x)=e^{ialpha(t)}lambda^{1/2}(t)W(lambda(t)x)+e^{iDeltat}zeta^*+o_{dot H^1} (1)$ as $tright arrow +infty$, where$alpha(t)=alpha_0ln t$, $lambda(t)=t^{nu}$,$W(x)=(1+frac13|x|^2)^{-1/2}$ is the ground state and $zeta^*$is arbitrarily small in $dot H^1$
4

Výpadek elektrické energie z pohledu krizového štábu ORP Český Krumlov / Power outage from the perspective of the crisis staff ORP Czech Krumlov

FILIPOVÁ, Eva January 2015 (has links)
Electric energy is part of our lives. We use electric energy everyday in our lives at home or work. The use ranges from home lighting to using computers or traffic lights. Electric energy became the indispensable part of our days. Electric energy is included in the fields of critical infrastructure which is essential to maintain safety and running the country. Power cut of critical infrastructure jeopardize the common being of inhabitants and also the safety of this region. Critical infrastructure is based in the Czech law of crisis management nb. 240/2000Cl and also in government regulation nb. 432/2010Cl about criteria of dealing crisis infrastructure. It is necessary to be prepared for every aspect of power cuts in the critical infrastructure field thoroughly as power cut can endanger human society and state. Because of the serious threat human society and state is essential to the individual areas of critical infrastructure failures to adequately prepare.Readiness to electrical power outage is a main theme of this thesis. The thesis focus on region of Cesky Krumlov located in South Bohemia, Czech Republic. Theoretical part of thesis named Power outage from the perspective of the crisis staff ORP Cesky Krumlov deals the aspects of electric energy and critical infrastructure. Reader learns about production, transport and distribution of electrical energy. Reader can also find information about power outages black outs. The thesis explains the meaning of word Infrastructure and also clarifies critical infrastructure and following protection of critical infrastructure. The thesis includes more information about critical infrastructure i.e. which documents deals with the problem of critical infrastructure, when and why the protection of critical infrastructure started and who was pioneer of the field problem. The thesis also describes the field of blackouts and gives the examples of the biggest blackouts which have every occurred in the world. The thesis reveals the cause of mentioned blackouts if the cause was human error, technical problem or overload of transmission system. The thesis shows the impact of blackouts on suffering population time they spent without electricity and how many people was affected with blackout, to complete the picture of blackouts. The last chapter is about crises staff. Reader learns about meaning of crisis staff and why and in which situations is the crisis staff in session. The thesis names and describes the crisis staffs at every level and describes the structure of crisis staff on every level government crises staff, county crisis staff and region crisis staff. The researcher part of this thesis is focused on region of Cesky Krumlov. The region is divided in municipalities and its belonging townships.The thesis gives picture about region population and its average age. The thesis also gives information about main water reservoirs and watercourses in region. The thesis mentions the leading farm economies which can be jeopardize during electric power outage. The thesis defines and analyses secondary crisis situations, which can occur during long lasting electrical power outage. The conclusion focus on the thesis research question "Is crises staff of region CeskýKrumlov prepared for the crises of electrical power outage?" The answer for the research question was ascertain by methods of risk analysing-the Checklist analysis and SWOT analysis. The research question was answered, based on these two analyses. One method was used to check the readiness for electrical power outage and following protection of region population of crisis staff of region CeskýKrumlov. The second method marks off strong and weak parts, opportunities and threats from the electrical power cut point of view. Following percentage calculation shows, what is the biggest danger for region of Cesky Krumlov in the moment of electrical power outage.
5

Asymptotic properties of the dynamics near stationary solutions for some nonlinear Schrödinger équations / Propriétés asymptotiques de la dynamique dans un voisinage des solutions stationnaires de certaines équations de Schrödinger non-linéaires

Ortoleva, Cecilia Maria 18 February 2013 (has links)
Cette thèse est consacrée à l'étude de certains aspects du comportement en temps longs des solutions de deux équations de Schrödinger non-linéaires en dimension trois dans des régimes perturbatives convenables. Le premier modèle consiste en une équation de Schrödinger avec une non-linéarité concentrée obtenue en considérant une interaction ponctuelle de force $alpha$, c'est-à-dire une perturbation singulière du Laplacien décrite par un opérateur autoadjoint $H_{alpha}$, où la force $alpha$ dépend de la fonction d'onde : $ifrac{du}{dt}= H_alpha u$, $alpha=alpha(u)$. Il est bien connu que les éléments du domaine d'une interaction ponctuelle en trois dimensions peuvent être décrits comme la somme d'une fonction régulière et d'une fonction ayant une singularité proportionnelle à $|x - x_0|^{-1}$, où $x_0$ est l'emplacement du point d'interaction. Si $q$ est la charge d'un élément du domaine $u$, c'est-à-dire le coefficient de sa partie singulière, alors pour introduire une non-linéarité, on fait dépendre la force $alpha$ de $u$ selon la loi $alpha=-nu|q|^sigma$, avec $nu > 0$. Ce modèle est défini comme une équation de Schrödinger non-linéaire focalisant de type puissance avec une non-linéarité concentrée en $x_0$. Notre étude regarde la stabilité orbitale et asymptotique des ondes stationnaires de ce modèle. Nous prouvons l'existence d'ondes stationnaires de la forme $u (t)=e^{iomega t}Phi_{omega}$, qui soient orbitalement stables pour $sigma in (0,1)$ et orbitalement instables quand $sigma geq 1.$ De plus nous montrons que si $sigma in (0,frac{1}{sqrt 2}) cup (frac{1}{sqrt 2}, 1)$, alors chaque onde stationnaire est asymptotiquement stable, à savoir que pour des données initiales proches d'un état stationnaire dans la norme d'énergie et appartenant à un espace $L^p$ pondéré où les estimations dispersives sont valides, l'affirmation suivante est vérifiée : il existe $omega_{infty} > 0$ et $psi_{infty} in L^2(R^3)$ tel que $psi_{infty} = O_{L^2}(t^{-p})$ quand $t rightarrow +infty$, tel que $u(t) = e^{iomega_{infty} t +il(t)} Phi_{omega_{infty}} +U_t*psi_{infty} +r_{infty}$, où $U_t$ est le propagateur de Schrödinger libre, $p = frac{5}{4}$, $frac{1}{4}$ respectivement en fonction de $sigma in (0, 1/sqrt{2})$, $sigma in left( frac{1}{sqrt{2}}, frac{sqrt{3} +1}{2sqrt{2}} right)$, et $l(t)$ est une fonction à croissance logarithmique qui apparaît quand $sigma in (frac{1}{sqrt{2}}, sigma^*)$, où $sigma^* in left( frac{1}{sqrt{2}},frac{sqrt{3} +1}{2sqrt{2}} right]$. Notons que dans ce modèle les non-linéarités pour lesquelles on a la stabilité asymptotique sont sous-critiques dans le sens où quelle que soit la donnée initiale il n'y a pas de solutions explosives. Quant au deuxième modèle, il s'agit de l'équation de Schrödinger non-linéaire focalisant à énergie critique : $i frac{du}{dt}=-Delta u-|u|^4 u$. Pour ce cas, nous prouvons, pour tout $nu$ et $alpha_0$ suffisamment petits, l'existence de solutions radiales à énergie finie de la forme $u(t,x)=e^{ialpha(t)}lambda^{1/2}(t)W(lambda(t)x)+e^{iDelta t}zeta^*+o_{dot H^1} (1)$ tout $trightarrow +infty$, où $alpha(t)=alpha_0ln t$, $lambda(t)=t^{nu}$, $W(x)=(1+frac13|x|^2)^{-1/2}$ est l'état stationnaire et $zeta^*$ est arbitrairement petit en $dot H^1$ / The present thesis is devoted to the investigation of certain aspects of the large time behavior of the solutions of two nonlinear Schrödinger equations in dimension three in some suitable perturbative regimes. The first model consist in a Schrödinger equation with a concentrated nonlinearity obtained considering a {point} (or contact) interaction with strength $alpha$, which consists of a singular perturbation of the Laplacian described by a self adjoint operator $H_{alpha}$, and letting the strength $alpha$ depend on the wave function: $ifrac{du}{dt}= H_alpha u$, $alpha=alpha(u)$.It is well-known that the elements of the domain of a point interaction in three dimensions can be written as the sum of a regular function and a function that exhibits a singularity proportional to $|x - x_0|^{-1}$, where $x_0$is the location of the point interaction. If $q$ is the so-called charge of the domain element $u$, i.e. the coefficient of itssingular part, then, in order to introduce a nonlinearity, we let the strength $alpha$ depend on $u$ according to the law $alpha=-nu|q|^sigma$, with $nu > 0$. This characterizes the model as a focusing NLS with concentrated nonlinearity of power type. In particular, we study orbital and asymptotic stability of standing waves for such a model. We prove the existence of standing waves of the form $u (t)=e^{iomega t}Phi_{omega}$, which are orbitally stable in the range $sigma in (0,1)$, and orbitally unstable for $sigma geq 1.$ Moreover, we show that for $sigma in(0,frac{1}{sqrt 2}) cup left(frac{1}{sqrt{2}}, frac{sqrt{3} +1}{2sqrt{2}} right)$ every standing wave is asymptotically stable, in the following sense. Choosing an initial data close to the stationary state in the energy norm, and belonging to a natural weighted $L^p$ space which allows dispersive stimates, the following resolution holds: $u(t) =e^{iomega_{infty} t +il(t)} Phi_{omega_{infty}}+U_t*psi_{infty} +r_{infty}$, where $U_t$ is the free Schrödinger propagator,$omega_{infty} > 0$ and $psi_{infty}$, $r_{infty} inL^2(R^3)$ with $| r_{infty} |_{L^2} = O(t^{-p}) quadtextrm{as} ;; t right arrow +infty$, $p = frac{5}{4}$,$frac{1}{4}$ depending on $sigma in (0, 1/sqrt{2})$, $sigma in (1/sqrt{2}, 1)$, respectively, and finally $l(t)$ is a logarithmic increasing function that appears when $sigma in (frac{1}{sqrt{2}},sigma^*)$, for a certain $sigma^* in left(frac{1}{sqrt{2}}, frac{sqrt{3} +1}{2sqrt{2}} right]$. Notice that in the present model the admitted nonlinearities for which asymptotic stability of solitons is proved, are subcritical in the sense that it does not give rise to blow up, regardless of the chosen initial data. The second model is the energy critical focusing nonlinear Schrödinger equation $i frac{du}{dt}=-Delta u-|u|^4 u$. In this case we prove, for any $nu$ and $alpha_0$ sufficiently small, the existence of radial finite energy solutions of the form$u(t,x)=e^{ialpha(t)}lambda^{1/2}(t)W(lambda(t)x)+e^{iDeltat}zeta^*+o_{dot H^1} (1)$ as $tright arrow +infty$, where$alpha(t)=alpha_0ln t$, $lambda(t)=t^{nu}$,$W(x)=(1+frac13|x|^2)^{-1/2}$ is the ground state and $zeta^*$is arbitrarily small in $dot H^1$
6

Human resources development (HRD) for effective localisation of workforces : an empirical study for identifying the key success factors for the energy sector in the United Arab Emirates (UAE)

Al-Marzouqi, Yehya January 2010 (has links)
The objective of the current study is to explore and identify the Critical Success Factors (CSFs), which impact upon the effective implementation of Human Resource Development (HRD) initiatives in support of nationalisation, and to recommend a model for practical application and future research. Accordingly the study focused on identifying and analysing the various factors in the localisation of a workforce with regard to five broad categories, namely: national level factors, organisational (policies and practices related) factors, organisational (HR related) factors, individual level (expatriate and experienced staff related) factors and individual level (UAE national related) factors. The data for the study was collected using both qualitative and quantitative methods. Qualitative methods were used to develop an in-depth case study of the Emiratisation process in an oil and gas organisation, as well as for identifying the critical success factors to be included in the survey questionnaire for collecting the quantitative data. The results of the study indicated that the critical success factors identified in the study are part of a complicated reality and need to be managed to ensure success of the localisation of a workforce. The mean scores obtained on the various factors differed significantly across the organisations or sub groups of respondents used in the study. This indicates that the impact of various factors that facilitate or constrain the localisation efforts are highly contextual and organisation specific. The findings of the study revealed valuable insights that could enrich not only future research in the area, but also the practical application of HR tools and methods to support the localisation process. The current study also developed a model for practical application and future research in the area. The model identified the role of HR strategies and tools as critical for managing the CSFs and ensuring the success of the process of localisation. The model developed in the current study also emphasises the need to define the 'success' of localisation in much broader terms, by addressing complex issues such as, employee morale and motivation, expectations of all employees, including expatriates and so forth, rather than just focusing on the number of UAE nationals employed and their competencies. The current study also identified some of the limitations of the study and highlighted suggestions for future research.
7

Sur l’explosion critique et surcritique pour les équations des ondes et de la chaleur semi-linéaires / On critical and supercritical blow-up for the semilinear heat and wave equations

Collot, Charles 08 November 2016 (has links)
Cette thèse porte sur l’étude des propriétés qualitatives des solutions des équations des ondes et de la chaleur semi-linéaires. Les résultats qui y sont décrits sont les suivants. Les deux premiers concernent l’existence et la description de dynamiques explosives de concentration en temps fini de l’état stationnaire à symétrie radiale dans le régime dit énergie surcritique ; en outre, pour l’équation des ondes la stabilité de ces phénomènes est étudiée dans le cas radial, et pour l’équation de la chaleur le cas plus général d’un domaine borné avec conditions de Dirichlet au bord est considéré. Le troisième porte sur la classification des dynamiques possibles près de l’état stationnaire radial pour l’équation de la chaleur dans le régime dit énergie critique, trois scénarios ayant lieu : la stabilisation, l’instabilité par explosion auto-similaire à profil explosif constant en espace, et l’instabilité par dissipation vers la solution nulle. Enfin, le quatrième a pour objet l’existence et la stabilité de profils explosifs auto-similaires non constants en espace pour l’équation de la chaleur dans le cas énergie surcritique / This thesis is devoted to the study of qualitative properties for solutions to the semilinear heat and wave equations. The results that are described are the following. The first two concern the existence and description of blow-up dynamics in which the radially symmetric stationary state is concentrated in finite time in the so-called energy supercritical regime; in addition, for the wave equation the stability of these phenomena is studied in the radial case, and for the heat equation the more general case of a bounded domain with Dirichlet condition at the boundary is considered. The third one deals with the classification of the possible dynamics near the radial stationary state for the heat equation in the so-called energy critical regime, where three scenarii occur: stabilization, instability by blow-up with the constant in space blow-up profile, and instability by dissipation to the null solution. Eventually, in the forth result we investigate the existence and the stability of self-similar blow-up profiles that are not constant in space, for the heat equation in the energy supercritical case

Page generated in 0.073 seconds