The idea underlying the present study was to apply twisting in order to introduce different levels of transverse pressure. The modified structure affected both the bonding level and the evolution of the damage in the yarn. In order to isolate this effect in a broader context, additional parameters were included in the experiment design, namely effects of loading rate, specimen length and filament diameter (directly linked to the fineness of the yarn). These factors have been studied in various contexts by several authors. Some related studies on involved factors will be briefly reviewed.

Les principaux objets étudiés dans cette thèse sont les équations décrivant le morphisme de groupe sur une variété abélienne, plongée dans un espace projectif, et leurs applications en cryptographie. Notons g sa dimension et k son corps de définition. Ce mémoire est composé de deux parties. La première porte sur l'étude des courbes d'Edwards, un modèle pour les courbes elliptiques possédant un sous-groupe de points k-rationnels cyclique d'ordre 4, connues en cryptographie pour l'efficacité de leur loi d'addition et la possibilité qu'elle soit définie pour toute paire de points k-rationnels (loi d'addition k-complète). Nous en donnons une interprétation géométrique et en déduisons des formules explicites pour le calcul du couplage de Tate réduit sur courbes d'Edwards tordues, dont l'efficacité rivalise avec les modèles elliptiques couramment utilisés. Cette partie se conclut par la génération, spécifique au calcul de couplages, de courbes d'Edwards dont les tailles correspondent aux standards cryptographiques actuellement en vigueur. Dans la seconde partie nous nous intéressons à la notion de complétude introduite ci-dessus. Cette propriété est cryptographiquement importante car elle permet d'éviter des attaques physiques, comme les attaques par canaux cachés, sur des cryptosystèmes basés sur les courbes elliptiques ou hyperelliptiques. Un précédent travail de Lange et Ruppert, basé sur la cohomologie des fibrés en droite, permet une approche théorique des lois d'addition. Nous présentons trois résultats importants : tout d'abord nous généralisons un résultat de Bosma et Lenstra en démontrant que le morphisme de groupe ne peut être décrit par strictement moins de g+1 lois d'addition sur la clôture algébrique de k. Ensuite nous démontrons que si le groupe de Galois absolu de k est infini, alors toute variété abélienne peut être plongée dans un espace projectif de manière à ce qu'il existe une loi d'addition k-complète. De plus, l'utilisation des variétés abéliennes nous limitant à celles de dimension un ou deux, nous démontrons qu'une telle loi existe pour leur plongement projectif usuel. Finalement, nous développons un algorithme, basé sur la théorie des fonctions thêta, calculant celle-ci dans P^15 sur la jacobienne d'une courbe de genre deux donnée par sa forme de Rosenhain. Il est désormais intégré au package AVIsogenies de Magma. / The main objects we study in this PhD thesis are the equations describing the group morphism on an abelian variety, embedded in a projective space, and their applications in cryptograhy. We denote by g its dimension and k its field of definition. This thesis is built in two parts. The first one is concerned by the study of Edwards curves, a model for elliptic curves having a cyclic subgroup of k-rational points of order 4, known in cryptography for the efficiency of their addition law and the fact that it can be defined for any couple of k-rational points (k-complete addition law). We give the corresponding geometric interpretation and deduce explicit formulae to calculate the reduced Tate pairing on twisted Edwards curves, whose efficiency compete with currently used elliptic models. The part ends with the generation, specific to pairing computation, of Edwards curves with today's cryptographic standard sizes. In the second part, we are interested in the notion of completeness introduced above. This property is cryptographically significant, indeed it permits to avoid physical attacks as side channel attacks, on elliptic -- or hyperelliptic -- curves cryptosystems. A preceeding work of Lange and Ruppert, based on cohomology of line bundles, brings a theoretic approach of addition laws. We present three important results: first of all we generalize a result of Bosma and Lenstra by proving that the group morphism can not be described by less than g+1 addition laws on the algebraic closure of k. Next, we prove that if the absolute Galois group of k is infinite, then any abelian variety can be projectively embedded together with a k-complete addition law. Moreover, a cryptographic use of abelian varieties restricting us to the dimension one and two cases, we prove that such a law exists for their classical projective embedding. Finally, we develop an algorithm, based on the theory of theta functions, computing this addition law in P^15 on the Jacobian of a genus two curve given in Rosenhain form. It is now included in AVIsogenies, a Magma package.

Ce travail de thèse est principalement centré sur l’étude des processus photophysiques fondamentaux de nouveaux composés organiques à transfert de charge dérivés de styrylpyridine, réalisée grâce à des mesures de fluorescence résolue en temps à l’échelle picoseconde et d’absorption transitoire à l’échelle femtoseconde. Nous nous sommes tout d’abord intéressés au comportement des états excités de deux nouvelles hémicyanines. Les molécules de diméthoxystyrylpyridine méthylées ont montré l’établissement d’un équilibre entre les conformations syn et anti différent à l’état excité comparé à l’état fondamental, représenté par un temps de décroissance rapide de fluorescence. La deuxième constante de temps correspond à la dépopulation de l’état excité par les voies non radiatives telles que l’isomérisation et le twist du donneur de charge (effet « loose-bolt »). Concernant le dérivé de styrylpyridinium où le groupement phényl a été remplacé par diméthlaminothiophene, nos études ont prouvé l’implication du mouvement de rotation du groupement méthylpyridinium ainsi que l’intervention du croisement inter-système comme voies de relaxation. Dans un second temps, nous nous sommes penchés sur les propriétés de complexation de la molécule de styrylpyridine sur laquelle a été substitué un éther-couronne. Nos études nous ont permis de mettre en évidence la présence de deux centres de complexation (un au centre de la couronne, l’autre sur l’azote de la pyridine) montrant une sélectivité différente vis-à-vis des cations métalliques. Les stoechiométries ont pu être confirmées par une analyse des temps de réorientation des complexes formés. Après avoir étudié les divers composés constituant des « briques » élémentaires en vue de systèmes supramoléculaires plus élaborés, nous nous sommes intéressés à leurs éventuelles applications avec l’étude de systèmes pour la collecte et le transfert d’énergie. Nous avons tout d’abord démontré l’existence d’un transfert d’énergie ultra-rapide (180 fs à 6 ps) et ultra-efficace (>99.7%) dans des systèmes bichromophoriques contenant deux styrylpyridines avec un éther-couronne et asymétrisés par l’introduction d’un cation Mg2+ dans une seule couronne. Celui-ci se fait de la partie complexée vers la partie non complexée par interaction coulombienne. Une autre application envisagée réside dans la construction de complexes à métaux de transition pour le stockage d’énergie ou le stockage d’information. Nous avons tout d’abord étudié la formation d’un système supramoléculaire basé sur le phénanthroline et contenant quatre éther-couronnes libres. Nous avons mis en évidence l’existence d’un équilibre entre états singulets et triplets excités dans ces composés complexés avec Cuivre(I) ou Argent(I). Dans un second temps, nous avons étudié la formation de complexes liant deux bipyridines substitués contenant un éther-couronne à un ion Fe2+. Un tel complexe présente des propriétés de transition de spin BS?HS. Nos études ont ensuite révélé la formation de complexes à métaux de transition de taille nanométrique lors de l’ajout d’ions Ba2+. / This Ph.D. work mainly deals with the study of fundamental photophysical processes of new styrylpyridine-type organic compounds showing charge transfer, realised using picosecond fluorescence and femtosecond transient absorption. We were interested first in the excited-state behaviour of two new hemicyanines. Methylated dimethoxystyrylpyridines molecules showed the establishment of an equilibrium between syn and anti conformations which is different in the excited state compared to the ground state, represented by a fast relaxation time of fluorescence. The second time constant corresponds to depopulation of the the excited state by non-radiative pathways as isomerization and donor twist (« loose-bolt »). Concerning styrylpyridinium derivative where phenyl group was replaced by dimethylaminothiophene, our studies proved involvment of rotation of methylpyridinium group and intersystem crossing as relaxation pathways. Secondly, we were interested in complexation properties of ether-crown susbstituted styrylpyridine molecule. Our studies showed the presence of two complexation centers (one in the center of the crown, the other one on the nitrogen of pyridine) having a different selectivity for metallic cations. Stoichiometries were confirmed by analysis of the reorientation times of formed complexes. After the study of our different compounds as elementary « building–blocks » for more complex supramolecular systems, we were interested in their potential applications with the study of systems for collection and energy transfer. First, we highlighted the existence of an ultra fast (180 fs to 6 ps) and ultra efficient (>99.7%) intramolecular energy transfer in bichromophoric systems containing two ether-crowned styrylpyridines and dissymetrised by binding of a Mg2+ cation in only one crown. It occurs from the complexed part to the non-complexed one by coulombic interaction. Another envisaged application can be the construction of complexes containing transition metals for energy or information storage. We studied first the building of a supramolecular system based on phenanthroline and containing four free ether-crowns We also proved that there exists an equilibrium between singlet and triplet excited states in these compounds complexed with Copper(I) or Silver(I). Secondly, we studied formation of complexes binding two ether-crown substituted bipyridines to a Fe2+ ion. Such a complex has got some spin crossover properties. Then, we showed that the addition of Ba2+ ions induce formation of transition metals complexes with nanometric size.

In this thesis, shows a current issue for free space optics, limiting their use in practice with regard to the availability and reliability. They conducted measurements on wireless optical links and the observed values is calculated by the availability of the connection. Subsequently, measurements are performed on alternate versions of wireless and copper connections. Observed values were compared with a wireless optical link. It is made of optical design of wireless connections at home.

Thesis is devoted to development of an database algorithm for selection (or necking selection) of suitable type of heat exchanger for given industrial application. Database creates a part of multipurpose calculation system containing three individual modules: (i) module for selection (or necking selection) of type of heat exchanger for given application, (ii) module for thermal-hydraulic design or rating of heat exchanger, (iii) module for calculation of investments and operating cost. Thesis describes details of method for selection of suitable heat exchanger type for given application and presents and discuss individual criteria for selection process which influence values in tables of priorites for given equipment. These tables are unavoible part of selection algorithm. Details of software application of selection algorithm are also presented in the thesis. Description of behaviour of individual types of heat exchanger creates important part of thesis. Practical application of developed selection algorithm is demonstrated on several industrial examples.

No description available.

In control technique there is evident highly expressive trend of shifting from efficient central managing systems towards smaller systems which are distributed on technology and which are connected by communication bus. There is no need to link all signals to central management system, operation is then distributed and realized directly in individual parts of technology. That’s why these systems are called distributive managing systems. Distributive managing systems are widely used not only in industrial applications but also in buildings, cars, etc..

Recent efforts to classify off-shell representations of supersymmetry without a central charge have focused upon directed, supermultiplet graphs of hypercubic topology known as Adinkras. These encodings of Super Poincare algebras, depict every generator of a chosen supersymmetry as a node-pair transformtion between fermionic bosonic component fields. This research thesis is a culmination of investigating novel diagrammatic sums of gauge-quotients by supersymmetric images of other Adinkras, and the correlated building of field theoretic worldline Lagrangians to accommodate both classical and quantum venues. We find Ref [40], that such gauge quotients do not yield other stand alone or "proper" Adinkras as afore sighted, nor can they be decomposed into supermultiplet sums, but are rather a connected "Adinkraic network". Their iteration, analogous to Weyl's construction for producing all finite-dimensional unitary representations in Lie algebras, sets off chains of algebraic paradigms in discrete-graph and continuous-field variables, the links of which feature distinct, supersymmetric Lagrangian templates. Collectively, these Adiankraic series air new symbolic genera for equation to phase moments in Feynman path integrals. Guided in this light, we proceed by constructing Lagrangians actions for the N = 3 supermultiplet YI /(iDI X) for I = 1, 2, 3, where YI and X are standard, Salam-Strathdee superfields: YI fermionic and X bosonic. The system, bilinear in the component fields exhibits a total of thirteen free parameters, seven of which specify Zeeman-like coupling to external background (magnetic) fluxes. All but special subsets of this parameter space describe aperiodic oscillatory responses, some of which are found to be surprisingly controlled by the golden ratio, [phi] = 1.61803, Ref [52]. It is further determined that these Lagrangians allow an N = 3 - > 4 supersymmetric extension to the Chiral-Chiral and Chiral-twistedChiral multiplet, while a subset admits two inequivalent such extensions. In a natural proiii gression, a continuum of observably and usefully inequivalent, finite-dimensional off-shell representations of worldline N = 4 extended supersymmetry are explored, that are variate from one another but in the value of a tuning parameter, Ref [53]. Their dynamics turns out to be nontrivial already when restricting to just bilinear Lagrangians. In particular, we find a 34-parameter family of bilinear Lagrangians that couple two differently tuned supermultiplets to each other and to external magnetic fluxes, where the explicit parameter dependence is unremovable by any field redefinition and is therefore observable. This offers the evaluation of X-phase sensitive, off-shell path integrals with promising correlations to group product decompositions and to deriving source emergences of higher-order background flux-forms on 2-dimensional manifolds, the stacks of which comprise space-time volumes. Application to nonlinear sigma models would naturally follow, having potential use in M- and F- string theories.