Η παρούσα μεταπτυχιακή διπλωματική εργασία ασχολείται με τον άμεσο υπολογισμό του μη γραμμικού δείκτη διάθλασης με τη βοήθεια μιας απλής μαθηματικής σχέσης και ενός πίνακα που παράγαμε, εφαρμόζοντας την τεχνικής Ζ-scan με απευθείας μέτρηση των διαστάσεων της δέσμης και τη χρήση ελλειπτικής γκαουσιανής δέσμης. Προτού αναφερθούμε στη μέθοδο υπολογισμού που προτείνουμε, θα γίνει εισαγωγή στη μη γραμμική οπτική, στη συνέχεια θα αναλυθούν οι βασικές μορφές των δεσμών λέιζερ που χρησιμοποιούνται και μετά τα φαινόμενα της αυτό-εστίασης και από-αύτο-εστίασης, που είναι βασικά για την κατανόηση της λειτουργίας της τεχνικής Ζ-scan και της ερμηνείας των καμπυλών Ζ-scan. Έπειτα παρουσιάζεται η τεχνική Ζ-scan και οι διάφορες παραλλαγές της με τα πλεονεκτήματα και τα μειονεκτήματα τους. Κατόπιν μελετάται η μορφή των καμπυλών Ζ-scan με απευθείας μέτρηση των διαστάσεων της δέσμης για κυκλικές και ελλειπτικές Γκαουσιανές δέσμες. Τέλος, εξηγούμε πως μέσω πολλών εξομοιώσεων Ζ-scan που πραγματοποιήσαμε, καταφέραμε να παράγουμε τη μαθηματική σχέση και τον αντίστοιχο πίνακα, που μας φέρνουν στο επιθυμητό αποτέλεσμα του υπολογισμού του μη γραμμικού δείκτη διάθλασης ενός υλικού αποφεύγοντας τους επίπονους και χρονοβόρους μαθηματικούς υπολογισμούς του παρελθόντος. / -

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Matemática, 2016. / Submitted by Albânia Cézar de Melo (albania@bce.unb.br) on 2016-05-19T15:35:05Z No. of bitstreams: 1 2016_RegianeLopesOliveira.pdf: 1053672 bytes, checksum: 32c45fb7b8dc64c0bc2d01ae4dd2a47d (MD5) / Approved for entry into archive by Marília Freitas(marilia@bce.unb.br) on 2016-05-28T11:24:59Z (GMT) No. of bitstreams: 1 2016_RegianeLopesOliveira.pdf: 1053672 bytes, checksum: 32c45fb7b8dc64c0bc2d01ae4dd2a47d (MD5) / Made available in DSpace on 2016-05-28T11:24:59Z (GMT). No. of bitstreams: 1 2016_RegianeLopesOliveira.pdf: 1053672 bytes, checksum: 32c45fb7b8dc64c0bc2d01ae4dd2a47d (MD5) / Neste trabalho estudamos uma família de relações de equivalência de nidas nos vértices de um dígrafo, as chamadas relações de alcance. Primeiramente, apresentamos diversas propriedades gerais das relações em questão e, então estudamos tais relações em conexão com propriedades de grupos de automor smos de dígrafos transitivos. Em particular, o principal resultado apresentado mostra que se um dígrafo transitivo D admite um subgrupo nilpotente H do grupo de automor smo Aut(D) de D, agindo com uma quantidade nita de órbitas sobre D, então a classe de nilpotência de H e o número de órbitas estão intimamente relacionadas com determinadas propriedades das relações de alcance. Além disso, estudamos como as propriedades das relações de alcance estão relacionadas com outras propriedades do dígrafo, tais como 'ter a propriedade Z' e condições de crescimento. _____________________________________________________________________________ ABSTRACT / In this work we study a family of equivalence relations de ned in the vertices of a digraph, the called reachability relations. First, we present several general properties of the relations in question and then we study such relations in connection with properties of automorphism groups of transitive digraphs. In particular, the main result shows that if a transitive digraph D admits a nilpotent subgroup H of the automorphism group Aut(D) of D acting with nitely many orbits on D, then the nilpotent class of H and the number of orbits are closely related to determined properties of the reachability relations. Futhermore, we study how properties of the reachability relation are related with others properties of digraphs, such as 'having propety Z' and growth conditions.

The aim of this dessertation work was reaserch which included monitoring and evaluation of kits unable for collection and processing off vineyard cuttings for energy purposes. Based on the basic objective data entry were performed model calculations of operating cost of two different sets. One consisting of a tractor and the other being a cutting the wood catcher. At the same time , closely monitoring the performance of palletising lines , that have been experimentally used for the production of pallets from waste vine cuttings materials and two other materials such as raw pine saw dust and straw . The produced paletts were determinate by their main mechanical -physical properties including calorific value . The conclusion is that at the moment, as current model analysis shows ,the cost of pallet production is at the level of 1837,38kč.t-1.

The purpose of this thesis is a survey of existing examples of furniture made from waste material, subsequent investigations in the field of waste management in Brno in order to find a suitable waste material for furniture making, and finally its own design and implementation.

Partículas massivas fracamente interagentes (WIMPs) são um dos mais atrativos candidatos para a matéria escura. Tais partículas são também muito promissoras em termos de detecção direta e indireta, pois elas devem possuir alguma conexão com as partículas do Modelo Padrão. Nesse contexto, extensões do Modelo Padrão podem introduzir candidatos para essas partículas de matéria escura. Propomos um modelo de extensão dupla para descrever as WIMPs, também chamadas de partículas escuras. Essa extensão é feita adicionando dois grupos de simetrias de calibre U(1) ao Modelo Padrão, um via mecanismo de Stueckelberg e o outro via mecanismo de Higgs. O mecanismo de Stueckelberg é um dos caminhos para garantir a invariância de calibre em bósons vetoriais massivos. Então, obtemos dois novos bósons de calibre, um chamado Z′ que é massivo e o outro γ′ (fóton escuro), que não possui massa e não interage com partículas do Modelo Padrão. A densidade de relíquia obtida experimentalmente pelas sondas espaciais WMAP e Planck auxilia na obtenção do valor mais provável para a massa do WIMP e, assim, podemos fixar outros parâmetros importantes para o modelo. Fazemos uma estimativa do impacto da presença de matéria escura e, principalmente, da emissão de fótons escuros no resfriamento de anãs brancas e de estrelas de nêutrons. Alguns resultados e perspectivas são apresentados. / Weakly interacting massive particles (WIMPs) are one of the most attractive candidates for dark matter. Such particles also are very promising in terms of direct and indirect detection, because they must have some connection to Standard Model (SM) particles. In this context, extensions of the SM can introduce candidates for these dark matter particles. In this sense, we propose a double extension model to describe the weakly interacting massive particles (WIMPs) or sometimes called dark particles. This extension is done by adding two extra U(1) gauge groups to the Standard Model, one via Stueckelberg mechanism and the other via Higgs mechanism. The Stueckelberg mechanism is one of the ways to ensure gauge invariance . Then we get two new gauge bosons, one called Z′ which is massive and the other γ′ (dark photon), which is massless and does not interact with the Standard Model particles. The relic density experimentally obtained by the WMAP and Planck spacecrafts will help in getting the most likely value for the mass of the WIMP and we can thus set other important parameters for the model. We estimate the impact of the presence of dark matter, and especially dark photon emission, in the cooling of white dwarfs and neutron stars. Some results and perspectives are presented.

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