Hydrogen fuel cells are devices used to generate electricity from the electrochemical reaction between air and hydrogen gas. An attractive advantage of these devices is that their byproduct is water, which is very safe to the environment. However, hydrogen fuel cells still lack some improvements in terms of increasing their life time and electricity production, decreasing power losses, and optimizing their operating conditions. In this thesis, the cathode part of the hydrogen fuel cell will be considered. This part mainly consists of an air gas channel and a gas diffusion layer. To simulate the fluid dynamics taking place in the cathode, we present two models, a general model and a simple model both based on a set of conservation laws governing the fluid dynamics and chemical reactions. A numerical method to solve these models is presented and verified in terms of accuracy. We also show that both models give similar results and validate the simple model by recovering a polarization curve obtained experimentally. Next, a shape optimization problem is introduced to find an optimal design of the air gas channel. This problem is defined from the simple model and a cost functional, $E$, that measures efficiency factors. The objective of this functional is to maximize the electricity production, uniformize the reaction rate in the catalytic layer and minimize the pressure drop in the gas channel. The impact of the gas channel shape optimization is investigated with a series of test cases in long and short fuel cell geometries. In most instances, the optimal design improves efficiency in on- and off-design operating conditions by shifting the polarization curve vertically and to the right. The second primary goal of the thesis is to analyze mathematical issues related to the introduced shape optimization problem. This involves existence and uniqueness of the solution for the presented model and differentiability of the state variables with respect to the domain of the air channel. The optimization problem is solved using the gradient method, and hence the gradient of $E$ must be found. The gradient of $E$ is obtained by introducing an adjoint system of equations, which is coupled with the state problem, namely the simple model of the fuel cell. The existence and uniqueness of the solution for the adjoint system is shown, and the shape differentiability of the cost functional $E$ is proved.

Les travaux de cette thèse portent sur la modélisation et l’étude numérique dessystèmes couplés de deux équations de Schrödinger non linéaires. Dans un premiertemps, nous considérons un système de deux équations de Schrödinger non linéairesPT −symétrique qui modélise des phénomèmes de fibre optique biréfringent. Lecomportement de la solution est étudié dans certains espaces comme l’espace de SobolevH1. De plus, l’étude numérique du modèle est faite afin de valider les résultatsanalytiques et, montre clairement le comportement qualitatif de la solution dansles espaces choisis. Pour ce même modèle en dimension supérieure, des conditionssuffisantes sont établies pour que la solution explose en temps fini pour certainesnon linéarités et pour le cas général de la non linéarité focalisante, nous faisonsl’étude numérique du modéle et nous présentons certains cas d’explosion de la solutionen temps fini et aussi des solutions du modèle qui existent tout le temps.D’autre part, nous adressons un nouveau modèle d’équations discrètes de Schrödingernon linéaires PT -symétrique. Un tel modèle décrit la dynamique d’une chaînede pendules faiblement couplés près d’une résonance entre une force paramétriqueet la fréquence linéaire des pendules. En vue d’étudier la stabilité des pendules, desconditions suffisantes ont été établies sur les paramètres du modèle pour que la solutiond’équilibre zéro soit linéairement et non linéairement stable. Des expériencesnumériques sont présentées pour valider les résultats analytiques et pour caractériserla déstabilisation de la chaîne de pendules couplés dans la région d’instabilité. / The works of this thesis concern the modeling and the numerical study of thesystems of two coupled nonlinear Schrödinger equations. At first, we considered aparity-time-symmetric system of the two coupled nonlinear Schrödinger (NLS) equationsthat modeled phenomenons in birefringent nonlinear optical fiber. We studythe behavior of the solution in some spaces like the Sobolev space H1. And we studythe numerical aspect of the model which clearly shows the behavior of the solutionin the chosen space. For the same model in higher dimension, we establish sufficientconditions for the initial conditions to blow up in finite time for some nonlinearityand for others we do the numerical study of the model and we present some casesof blowing up of the solution in finite time and also of the solutions of the modelthat exist all the time. On the other hand, we address a new model of discrete nonlinearSchrödinger equations PT -symmetric. A such model describes dynamics inthe chain of weakly coupled pendula pairs near the resonance between the parametricallydriven force and the linear frequency of each pendulum. In order to studythe stability of the pendulums, we establish sufficient conditions on the parametersof the model so that the equilibrium solution is stable. Numerical experiments arepresented to validate the analytical results and to characterize the unstabilizationof the coupled pendulum chain in the region of instability.

The Becoming-other of the Existence, Essay on Contemporary Phenomenology, is both a systematic and a historical study of phenomenology. By choosing a systematic problem of becoming-other of the existence it attempts to present and to confront five major contemporary phenomenologists in France within a single phenomenological field: Henri Maldiney, Claude Romano, Jean-Luc Marion, Renaud Barbaras, and Marc Richir. The study enters phenomenology with Edmund Husserl and presents some key original concepts invented by two generations of post-husserlian authors who marked out the road to contemporary phenomenology: Martin Heidegger, Erwin Straus, Maurice Merleau-Ponty, Jan Patočka, Emmanuel Lévinas. Then it turns to "evential empiricism" in the work of Maldiney and Romano who consider the existent and the world in their belonging-together: the event is thus understood as co-birth of the subject and the world. Nevertheless, because of the fact that the existence that "becomes-other" is necessarily a finite existence, a radically separated existence from the metaphysical transcendence of the world, three other authors must become involved in the discussion: Marion, whose adonné is a limit of the givenness, and then Barbaras and Richir who explore the most archaic layers of the subjectivity within a...

We study nonlinear evolutionary partial differential equations that can be viewed as a generalization of the heat equation where the temperature gradient is bounded but the heat flux is apriori only a measure. We consider this system in spatially periodic setting and use higher differentiability techniques to prove the existence and uniqueness of weak solution with integrable heat-flux for all values of the material parameter a. Under some more restrictive assumptions on a, we prove higher integrability of the heat flux. 1

IVANKO, Dana. Possibilities of social work in a situation of mass disasters in relation to the needs of victims. Prague: Faculty of Arts of Charles University in Prague, 2013. 87 pp. Diploma thesis. Diploma Thesis - Possibilities of social work in a situation of mass disasters in relation to the needs of victims - focuses on the area of psychosocial assistance and social work in mass disasters. It describes in deeper details the types of assistance in mass disasters, focusing on psychosocial assistance. The focus is on human, with its biological, psychological, spiritual and social needs. Then, social work in situations of mass disaster and competences of a social worker are introduced. A separate chapter discusses mobile crisis teams. To achieve the goals of this work, it presents an overview of standards of psychosocial assistance, including legislative basis of help in mass disasters in the Czech Republic. Research section provides an insight into the work of mobile crisis teams in the Czech Republic in the form of examples of good practice. The methodology will be elaborated based on the examples of work of mobile crisis teams, on what has proved successful in providing psychosocial assistance. Keywords Social work in mass disasters, psychosocial assistance, mass disaster, victims, needs of...

Cette th'ese est consacr'ee 'a l''etude et la r'esolution de certains probl'emes non lin'eaires du traitement du signal et de l'image via l'analyse convexe. Nous proposons une 'etude variationnelle unifi'ee de probl'emes inverses et de probl'emes de d'ecomposition de signaux qui ont, jusqu''a pr'esent, 'et'e 'etudi'es individuellement en raison de leur apparente disparit'e. Dans le mod'ele adopt'e, cette famille de probl'emes est r'eduite g'en'eriquement 'a la minimisation d'une somme de deux fonctions soumises 'a certaines propri'et'es de r'egularit'e. Des r'esultats d'existence, d'unicit'e et de caract'erisation du probl'eme ainsi pos'e sont obtenus. L'op'erateur proximal, introduit par Moreau en 1962 pour les besoins de la m'ecanique, joue un rˆole essentiel dans notre analyse. Nous l'utilisons notamment pour obtenir de nouveaux sch'emas non lin'eaires de d'ecomposition de signaux. Cet outil est par ailleurs au coeur de l'algorithme explicite-implicite que nous proposons pour la r'esolution du probl'eme g'en'erique. Ce cadre th'eorique est appliqu'e 'a l'analyse de signaux et 'a la restauration d'images. Les probl'emes de restauration que nous abordons sont pos'es sur des trames et notre approche permet de prendre en compte des contraintes de parcimonie ou de mod'eliser des formulations bay'esiennes avec des connaissances a priori sur les lois des coefficients de la d'ecomposition. Des r'esultats num'eriques sont fournis.

Dans cette thèse nous nous intéressons aux propriétés qualitatives et quantitatives des solutions de quelques équations d'ondes en milieux dispersifs ou dispersifs-dissipatifs. Dans une première partie, nous étudions le problème de Cauchy associé aux équations de Benjamin-Ono généralisées. A l'aide de transformées de jauge, combinées avec des outils d'analyse harmonique, nous prouvons des résultats concernant le caractère localement bien posé pour des données initiales de régularité minimale dans l'échelle des espaces de Sobolev. Dans une seconde partie, nous étudions le problème de Cauchy pour des versions dissipatives des équations de Benjamin-Ono et de Korteweg-de Vries. Nous mettons en évidence l'influence des effets dissipatifs sur ces équations en donnant des résultats optimaux sur leur caractère bien ou mal posé. Ceux-ci sont obtenus en travaillant dans des espaces de type Bourgain adaptés à la partie dispersive-dissipative. Pour finir nous étudions le comportement asymptotique des solutions des équations de KdV dissipatives, lorsque celles-ci existent pour tout temps, en calculant explicitement les premiers termes du développement asymptotique dans de nombreux espaces de Sobolev

Bakgrund: Människor som lever med obotlig sjukdom i livets slutskede kan leva med en hotad existens. I dessa fall kan palliativ vård vara en lämplig form av vård. Livskvalitet är ett sätt att mäta individers välbefinnande och påverkas av stöd. Stöd uppfattas som positivt när det sker motgångar i livet. Den subjektiva levda kroppen är där existensen lever genom och kan förändras på grund av sjukdom, då kan även existensen hotas. Sjuksköterskor behöver både stöd och kunskap inom den palliativa vården för att de ska känna trygghet i sitt arbete. Syfte: Beskriva patienters upplevelser av att leva med en obotlig sjukdom i livets slutskede. Metod: En kvalitativ innebördsanalys med sex stycken självbiografier användes för att svara på syftet. Resultat: Fyra teman framkom dessa var; Stöd kan underlätta sorgen, Att välja livskvalitet trots sjukdom, När kroppen inte är som förr och Förändrad syn på livet och döden. Diskussion: Stöd är inte endast en viktig aspekt för personer som lever med en obotlig sjukdom i livets slutskede, det är också viktigt för anhöriga och närstående. Sjuksköterskor behöver känna stöd från sina kollegor för att kunna utföra en så god vård som möjligt. Slutsats: Personer som lever med oboltig sjukdom kan få en förändrad livssyn då livet prioteras på ett sätt som det tidigare inte gjorts. / Background: People, who are living with incurable diseases, can be living with threatening existence. In these cases, palliative care can be an appropriate form of care. Quality of life is a way to measure individual’s well-being, and is affected by received support. Support is perceived as a positive influencer when people are faced with setbacks in life. The subjective lived body is where the existence lives through and may change due to illness, and then even existence is threatened. Nurses need both support and knowledge in the field of palliative care to feel confident in their work. Purpose: The purpose of this thesis is to investigate the patients’ experiences of living with an incurable disease in end life care. Method: In this thesis a qualitative meaning analysis is used. Six autobiographies are used to answer the purpose. Result: Four different themes were identified. They are; support can overcome the grief; Too choose life quality over sickness; When the body is not like it used to be; and lastly, a changed perception on life and death. Discussion: Support is not only important for the patient living with an incurable disease, but also for relatives and friends. Nurses need support from their colleagues so they can give the best care possible. Implication: People living with an incurable diseases can have a changed sight of life, when life portieres different than before.

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The purpose of this study was to determine the various values that influence nurses within the hospital, and ascertain, through comparison, any significant differences between the values of the floor nurse and the values of the emergency room nurse, The value systems (Tribalistic, Egocentric, Conformist, Manipulative, Sociocentric, and Existential) were developed by Clare W. Graves as the "Levels of Psychological Existence." A values test was utilized in order to collect data. The "Values for Nursing" test was administered to 161 nurses in a large metropolitan city in Texas. Specific hypotheses regarding value differences in nursing groups were tested.