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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.
91

Avaliação do crescimento facial em dois protocolos para cirurgias primárias em pacientes com fissura labiopalatina unilateral: ensaio clínico randomizado / Evaluation of facial growth in two primary protocols used in the surgical treatment of unilateral cleft lip and palate patients: a randomized clinical trial

Rui Manuel Rodrigues Pereira 07 March 2017 (has links)
Introdução e Objetivo: Nos pacientes com fissura labiopalatina unilateral (FLPU) as cirurgias primárias afetam, em graus variados, o crescimento da face, comprometendo a estética facial e a oclusão dentária. Diversos estudos enfatizam a necessidade de se estabelecer protocolos cirúrgicos que apresentem repercussões positivas no crescimento facial e no desempenho fonoarticulatório dos pacientes, visando a diminuição do custo biológico, social e financeiro do tratamento integral. Este estudo objetivou comparar os efeitos de dois protocolos cirúrgicos para palatoplastia primária, em um e em dois tempos cirúrgicos, este com o fechamento tardio do palato duro (FTPD) sobre o complexo maxilo-mandibular de pacientes com FLPU completa. A hipótese do autor é que o protocolo com FTPD propicie um melhor crescimento dentofacial. Métodos: Foi realizado um ensaio clínico randomizado no qual 64 pacientes, atendidos em um centro de referência no nordeste do Brasil, foram divididos em dois grupos que receberam tratamentos cirúrgicos distintos. O grupo de intervenção (GI) foi constituído por 32 pacientes submetidas à palatoplastia em dois tempos cirúrgicos: veloplastia realizada entre os 6 e 9 meses de idade e FTPD realizado entre 36 e 48 meses de vida. O grupo controle (GC) foi constituído por 30 pacientes submetidos a palatoplastia completa entre os 9 e 15 meses. A relação entre os arcos dentários foi avaliada, de maneira cega, por três ortodontistas calibrados usando o índice FYOI (Atack,1997). Também foram investigadas as alterações dimensionais na maxila, a gravidade da fissura e as complicações pós-cirúrgicas em relação aos dois protocolos cirúrgicos. Resultados: Os modelos de gesso para avaliação pelo FYOI foram obtidos dos pacientes de ambos os grupos com idade média de 55,5 meses. O grau de concordância foi excelente (Kappa = 0,76-0,90) entre os examinadores e bom intra-examinadores (Kappa = 0,67-0,87). Os escores médios do índice FYOI variaram de 2,04 no GI a 2,76 no GC, com diferença estatisticamente significante (p = 0,007). Quando os scores foram agrupados em três categorias, bom (escores 1 e 2), Regular (escore 3) e ruim (escores 4 e 5) verificou-se diferença significativa (p < 0,006) na categoria bom (escores 1 e 2) entre os grupos GI (74%) e GC (52%). Ao serem comparadas as distribuições pela mediana, foi encontrada diferença significativa (p = 0,024) entre os escores 1 dos grupos GI (31,2%) e GC (3,3%). A correlação entre a largura da fissura e a relação maxilo-mandibular avaliada pelo FYOI não foi evidenciada pelo método de Spearman. A ocorrência de fístulas oronasais foi de 9,4% no GI e 6,7% no GC, sem diferença significativa entre eles. Conclusões: a palatoplastia realizada em dois tempos cirúrgicos com FTPD, apresenta melhores desfechos relativos ao crescimento dentofacial em crianças com FLPU. Não foi encontrada associação entre a gravidade da fissura e os desfechos relacionados ao crescimento maxilar. Não há diferenças estatisticamente significantes entre os dois protocolos cirúrgicos em relação à ocorrência de fístulas e à diminuição da distância intercaninos e diminuição do comprimento do arco maxilar / Background and Objective: An adequate growth of dentofacial structures is one of the most important goals of unilateral cleft lip and palate(UCLP) treatment and has a definitive role in getting good aesthetic and dental occlusion outcomes. To the present date several papers highlight the need of evidence-based studies to find surgical protocols that can improve facial growth and speech results aiming to reduce the burden of care of overall treatment. This study has evaluated and compared the dental arch relationship at 5 years of age after two treatment protocols, one submitted to one stage cleft palate repair (CPR) and the other to a two stage CPR with delayed hard palate closure (DHPC). The author\'s hypothesis is that the DCHP protocol provides a better dentofacial growth. Methods: A randomized clinical trial was held to evaluate the maxilo-mandibular relations in two groups of initially 32 patients each, randomly chosen. The GI group (n=32) was submitted to veloplasty between 6-9 months of age and a DCHP palatoplasty between three and four years of of age. The immediate complications were evaluated, oronasal fistulas, and cleft severity and their relationships to the surgical protocols. The dental arch relationships were assessed by a blind panel of three independent orthodontists using the FYOI index. The Kappa statistics were calculated to ensure the level of confidence. The results were statistically tested by t and Q-squared tests. Results: The GI group consisted of 32 patients while the GC group consisted of 30 patients. The oronasal fistulas incidence rate was 9.4% (GI) and 6.7% (GC), and there was no association to surgical techniques. Study models of 62 patients at the average age of 55.5 months were available for assessment. Good to very good levels of intra- and interrater reliability were obtained (0.67-0.87 and 0.76-0.90). The mean index scores varied between 2.04 (GI) and 2.76 (GC) with a statistically significant difference (p=0.007). When all evaluations were distributed between indexes good (1 and 2), regular (3) and bad (4 and 5); a statistically significant difference was observed between the GI and GC groups (p = 0.006),. The GI Group presented a 74% rate of good scores, while the GC Group rated 52% in good scores. When comparing the distributions by median, a difference (p = 0.024) was found between scores 1 of the GI (31.2%) and GC (3.3%) groups. The correlation between the cleft severity and the dental arch relationships assessed by the FYOI was not evidenced by the Spearman method. Conclusions: The ECR results provide statistical evidence that the DCHP protocol delivers better outcomes related to dentofacial growth. There was no correlation found between the cleft severity, palatal width and the results related to maxilar growth. The prevalence of oronasal fistules is similar in both surgical protocols
92

Form-finding and Performance of Bending-active Structures. Proposals of Application to Lightweight Braced Arches.

Bessini Muñoz, Juan Gabriel 26 April 2021 (has links)
[ES] Hoy en día, la arquitectura moderna está orientada principalmente al empleo eficiente de materiales tecnológicos y sostenibles, la tecnificación del proceso de diseño, proyecto y construcción, y la búsqueda de soluciones muy ligeras. Estas ideas se reflejan en las estructuras flexo-activas, que recientemente han atraído considerable atención como nuevo paradigma para construir estructuras ligeras, tanto en el ámbito de la investigación como en la práctica. El término "flexión activa" hace referencia a una categoría de estructuras en las que la flexión se emplea en el proceso de configuración de su forma. Los sistemas estructurales flexo-activos incluyen barras o láminas incurvadas cuya geometría es el resultado de su deformación elástica desde una configuración inicial recta o plana. Hasta el momento, el número de realizaciones es limitado; se trata sobre todo de aplicaciones experimentales con funcionalidad arquitectónica o artística. La obtención de la configuración de equilibrio es una de las principales dificultades que aparecen en la fase de concepción, debido precisamente a la no linealidad de la respuesta estructural de las barras activas, así como a la posible interacción con otros elementos estructurales como membranas o cables, que trabajan por forma, y cuya geometría no se puede fijar de modo arbitrario. Los métodos computaciones de determinación de forma para estructuras flexo-activas incluyen modelos de elementos finitos con cables virtuales no lineales que se acortan hasta alcanzar la configuración final, o algoritmos de relajación dinámica que consideran las variables que caracterizan la deformación de las barras activas. Esta tesis doctoral tiene por objeto proporcionar un análisis en profundidad de la aplicabilidad del principio de flexión activa al diseño de estructuras ligeras, en particular a los puentes peatonales. Para ello, la investigación se aborda desde tres puntos de vista: a) modelización computacional; b) eficiencia estructural; c) diseño y construcción. En primer lugar, se lleva a cabo una revisión de la bibliografía existente, haciendo hincapié en los trabajos previos en el diseño de pasarelas con flexión activa. En el campo de la modelización computacional, se desarrolla un novedoso método numérico de determinación de forma para estructuras flexo-activas basado en el modelo geométricamente exacto para piezas alargadas (también conocido como la teoría de vigas de Reissner-Simó). Distintos ejemplos numéricos han sido reproducidos para mostrar la exactitud del método. La parte de la investigación relacionada con el análisis de la eficiencia estructural se centra en el comportamiento del sistema flexo-activo propuesto en esta tesis para el diseño de estructuras ligeras: el arco flexo-activo arriostrado (o atirantado). Se trata de un arco plano compuesto por una barra flexible y continuo que se activa por la acción de los cables principales que tiran de ambos extremos de la varilla, y de los puntales o cables secundarios que desvían el cable principal y actúan en ciertas secciones transversales. La parte computacional-analítica se completa con el desarrollo de un procedimiento numérico basado en algoritmos genéticos, con el fin de obtener configuraciones estructurales eficientes. La tesis finaliza con el diseño, fabricación y montaje de una pasarela flexo-activa hecha con tubos PRFV utilizando este tipo estructural, realizada en el laboratorio de modelos de la Universitat Politècnica de València. / [CA] Hui dia, l'arquitectura moderna està orientada principalment a l'ús eficient de materials tecnològics i sostenibles, la tecnificació del procés de disseny, projecte i construcció, i la cerca de solucions molt lleugeres. Aquestes idees es reflecteixen en les estructures flexo-actives, que recentment han atret considerable atenció com a nou paradigma per a construir estructures lleugeres, tant en l'àmbit de la investigació com en la pràctica. El terme "flexió activa" fa referència a una categoria d'estructures en les quals la flexió s'empra en el procés de configuració de la seua forma. Els sistemes estructurals flexo-actius inclouen barres o làmines incorbades, la geometria de les quals és el resultat de la seua deformació elàstica des d'una configuració inicial recta o plana. Fins al moment, el nombre de realitzacions és limitat; es tracta sobretot d'aplicacions experimentals amb funcionalitat arquitectònica o artística. L'obtenció de la configuració d'equilibri és una de les principals dificultats que apareixen en la fase de concepció, degut precisament a la no linealitat de la resposta estructural de les barres actives, així com a la possible interacció amb altres elements estructurals com a membranes o cables, que treballen per forma, i la geometria de la qual no es pot fixar de manera arbitrària. Els mètodes computacions de determinació de forma per a estructures flexo-actives inclouen models d'elements finits amb cables virtuals no lineals que s'escurcen fins a aconseguir la configuració final, o algorismes de relaxació dinàmica que consideren les variables que caracteritzen la deformació de les barres actives. Aquesta tesi doctoral té per objecte proporcionar una anàlisi en profunditat de l'aplicabilitat del principi de flexió activa al disseny d'estructures lleugeres, en particular als ponts per als vianants. Per a això, la investigació s'aborda des de tres punts de vista: a) modelització computacional; b) eficiència estructural; c) disseny i construcció. En primer lloc, es duu a terme una revisió de la bibliografia existent, amb recalcament en els treballs previs en el disseny de passarel·les amb flexió activa. En el camp de la modelització computacional, es desenvolupa un nou mètode numèric de determinació de forma per a estructures flexo-actives basat en el model geomètricament exacte per a peces allargades (també conegut com la teoria de bigues de Reissner-Simó). Diferents exemples numèrics han sigut reproduïts per a mostrar l'exactitud del mètode. La part de la investigació relacionada amb l'anàlisi de l'eficiència estructural se centra en el comportament del sistema flexo-actiu proposat en aquesta tesi doctoral per al disseny d'estructures lleugeres: l' arc flexo-actiu esbiaixat (o lligat). Es tracta d'un arc pla compost per un membre flexible i continu que s'activa per l'acció dels cables principals que tiren de tots dos extrems de la vareta, i dels puntals o cables secundaris que desvien el cable principal i actuen en certa secció transversal de la vareta. La part computacional-analítica es completa amb el desenvolupament d'un procediment numèric basat en algorismes de tipus genètic, amb la finalitat d'obtindre configuracions estructurals eficients. La tesi finalitza amb el disseny, fabricació i muntatge d'una passarel·la flexo-activa feta amb tubs PRFV utilitzant aquest tipus estructural, realitzada en el laboratori de models de la Universitat Politècnica de València. / [EN] Nowadays, modern architecture is focused on the search of efficient uses of technological and sustainable materials, high-tech concept-design-erection processes and the possibility to produce lightweight solutions with maximum elegance in shape. These ideas are reflected on bending-active structures, which recently attracted considerable attention as a new paradigm to build lightweight structures both in research and practice. The concept 'active bending' refers to a category of structures in which bending is used in the process of shape configuration. Bending-active structural systems include curved rods or shells which have been elastically bent from an initial straight or plane configuration. As of now, the number of realisations is limited; they are mostly experimental ones, with architectural or artistic nature. Form finding of the equilibrium configuration is one of the main difficulties during the conceptual phase, due to the non-linearity of the structural response of the active members, and also to the interaction with other form-active structural elements as membranes or cables, whose geometry cannot be prescribed in advance. Computational form-finding methods for bending-active structures include finite element models with non-linear virtual links that are shortened to reach the final form, or dynamic relaxation (explicit) algorithms to cope with the variables describing the response of the active members. This PhD thesis aims to provide an indepth analysis on the applicability of the active bending principle to the design of lightweight structures, in particular pedestrian bridges. For that purpose, the work is carried out from three points of view: (a) computational modelling and simulation; (b) structural performance and efficiency; (c) design and construction. First of all, a literature review on the topic and a overview of realisations in the fied of bending-active footbridges is provided. In the field of computational modelling, a novel form-finding method based on the geometrically exact rod model (or Reissner-Simo beam theory) is implemented. Numerical examples are also given to show the accuracy of the method. The part of the work related to the analysis of the structural performance and efficiency is focused on the bending-active configuration proposed in this PhD thesis for designing lightweight structures: the bending-active braced (or tied) arch. This is a simple planar arch composed of a continuous flexible member that is activated by the action of main cables pulling at both ends of the rod, and secondary struts or cables that deviate the main cable and act at certain cross-section of the rod. The computational-analytical part is completed with the development of a numerical procedure based on genetic algorithms to obtain efficient structural configurations. The thesis ends with the design, fabrication and assembling of a bending-active short footbridge made of GFRP tubes using this structural type, held in the laboratory of concept models of the Polytechnic University of Valencia. / The author has had the opportunity to join the research project: Sistemas estructuras flexo-activos- Concepción, desarrollo y análisis de nuevos prototipos (FLEXACT - grant BIA2105-69330- P) / Bessini Muñoz, JG. (2021). Form-finding and Performance of Bending-active Structures. Proposals of Application to Lightweight Braced Arches [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/165575 / TESIS
93

Numerical Investigation of Rock Support Arches

Rentzelos, Theofanis January 2019 (has links)
The Garpenberg mine, owned by the Boliden Mining group, has established a trial area at Dammsjön orebody in order to examine the possibility of increasing the productivity of the mine. The mine uses the rill mining method with a current rill height of 15 m. In order to increase the productivity, the mine is examining the possibility of increasing the height of the rill. The trial area is located at 882 m depth surrounded by dolomite on the hangingwall and quartzitic rock on the footwall side. Rock support arches have been installed, in addition to the regular support pattern, to test their effectiveness on stabilizing the ground around the drifts. The arches have been installed in every 6 m and every 3 m in different parts of the test area. Rock samples from the trial area were brought to the university laboratory for testing. The data gathered from the laboratory tests along with the data from the monitoring of the trial area were used to develop a calibrated numerical model. A three-dimensional (3-D) model was therefore created, by using the FLAC3D numerical code. After the calibration of the model a parametric study was conducted for different rill heights and different arch spacing to investigate the performance of the arches. Specifically, the case of no arch installation along with the cases of an installed arch every 6 m and 3 m were tested, for the rill heights of 15 m, 20 m, 25 m and 30 m. The study concluded that the arches assisted in reducing the ground convergence in the production drift. The results also showed that the total height of the rill bench yields regardless of its height. After the yielding, the rockmass can no longer support itself and caves under its own weight. The larger the rill height, the larger the volume of loose rock that has to be supported and thus, higher the convergence. Furthermore, it was also observed that, significant amount of convergence in the production drift occurred during the drifting of the top drive and less during the stoping of the rill bench. This indicates that, the timely installation of the arches is an important criterion for their performance.
94

ELABORATION D'UNE MÉTHODE DE PRÉDICTION DU VOLUME MAXIMAL D'UNE LAVE TORRENTIELLE (PREVENT)<br />Géomorphologie torrentielle,Topographie de terrain et Stéréophotogrammétrie sur photographies aériennes d'archives<br />Torrents du Manival, du Merdarêt et des Arches (Alpes-du-Nord, Isère, France)

Veyrat-Charvillon, Stéphane 09 December 2005 (has links) (PDF)
En ingénierie des risques torrentiels, les praticiens sont actuellement confrontés à un problème de gestion lié à la méconnaissance des volumes sédimentaires mobilisés par les crues. Généralement, les études cherchant à estimer ces volumes sédimentaires portent soit sur la production détritique des versants, soit sur la fourniture sédimentaire uniquement en sortie de bassin versant, mais rarement sur l'évaluation des stockages-déstockages le long du talweg ; elles ne fournissent donc pas de méthode (pluriel discutable) d'estimation des volumes sédimentaires satisfaisante. C'est pour répondre à ce questionnement des gestionnaires qu'est née cette recherche appliquée en géomorphologie torrentielle, basée sur la compréhension des processus de recharge et de transit sédimentaires au sein du chenal.<br />L'approche «globale» présentée ici peut être un complément aux travaux plus fréquents concernant la rhéologie et le comportement mécanique des matériaux, étudiés à une échelle plus fine, ainsi qu'aux études détaillées de certains processus géomorphologiques. Pour mener à bien ce travail, de nombreux outils ont été utilisés : photogrammétrie, observations de terrain et mesures topographiques, cartographie sur SIG et Modélisation Numérique de Terrain, géophysique, relevés pluviographiques et traitements statistiques, recueil d'archives. L'étude approfondie du bassin versant du Manival (Isère, Alpes-du-Nord) a permis de mieux comprendre le fonctionnement des processus sédimentaires et de mettre au point une méthode d'estimation des volumes en jeu. Cette méthode, qui permet de prédire le volume maximal d'une lave torrentielle majeure à venir (PREVENT), est basée sur une approche systémique et sur un concept du fonctionnement torrentiel privilégiant la dynamique sédimentaire du système.<br />La méthode de PREVENT a été par la suite appliquée à deux autres bassins versants isérois du même type, le Merdarêt et les Arches. L'étude diachronique des volumes sédimentaires de ces torrents montre que les résultats de la méthode proposée ont une cohérence satisfaisante. Cette thèse contribue à améliorer la connaissance scientifique des processus torrentiels, et par là même, apporte des outils théoriques et méthodologiques dans le domaine de l'ingénierie des risques naturels.
95

Nové brněnské hlavní nádraží a jeho veřejná prostranství / Brno New Train Station and its Public Spaces

Nytrová, Bohdana January 2020 (has links)
For almost one hundred years, Brno has been deciding where the place of a new main train station should be. The works have almost started several times, but the various affairs have always postponed it. Two years ago, it was finally decided that „the River option“ would be constructed. So far, only the technological template has been written – e. g. railway bridge or platforms outline. The thesis focuses on the architectural design of the main building, the roof construction above the railways and spaces below the station bridge. In the design, the outlying urban structures are also dealt with. These include the locations of a bus station, taxi services and bike stands. Moreover, the design also mentions the station’s connection to the city networks. The main motive of the design is to put the main train station building into the centre of the city’s attractions – to make it visible. A boulevard’s view is oriented to the St. Peter’s cathedral – a famous Brno’s building. Just as the mentioned cathedral, the station is important for the city and deserves to be seen. A strong arched construction on four pillars serves as a roof over the railways and places where most visitors are expected to be most of the time. The arch also connects the public transport lines and the bus station. Part of a roof shaped like waves around the main hall connects the structure with the riverside nearby.
96

Ανάλυση οριακής κατάστασης και σεισμικής επάρκειας λίθινων αψίδων / Limit state analysis and earthquake resistance of masonry arches

Αλεξάκης, Χαράλαμπος 09 July 2013 (has links)
Η παρούσα διατριβή επανεξετάζει την οριακή ανάλυση ευστάθειας των λίθινων αψίδων. Η οριακή ανάλυση ευστάθειας χρησιμοποιείται σήμερα ως το βασικό εργαλείο αποτίμησης της ευστάθειας τόξων και θολωτών κατασκευών από τοιχοποιία, όπως ακριβώς συνέβαινε και τους τελευταίους τέσσερις αιώνες. Παρά την τόσο μακρόχρονη ιστορία της μεθόδου, δεν έχουν πλήρως διασαφηνιστεί στην επιστημονική κοινότητα θεμελιώδης έννοιες και δεν έχουν σαφώς απαντηθεί ερωτήματα όπως: Ποιες είναι οι φυσικά πραγματοποιήσιμες γραμμές ώθησης και ποιες όχι; Ποια είναι η επίδραση της στερεοτομίας ενός τόξου στην οριακή του ευστάθεια; Ποιος είναι ο ρόλος της αλυσοειδούς καμπύλης και κατά πόσο αυτή είναι μία φυσικά αποδεκτή γραμμή ώθησης; Τι σχέση υπάρχει ανάμεσα στην κλίση της συνισταμένης θλιπτικής δύναμης και στην κλίση της γραμμής ώθησης στο σημείο εφαρμογής της; Η παρούσα διατριβή αναζητά απαντήσεις στα ερωτήματα αυτά, και έχει ως στόχο τη βαθύτερη κατανόηση της οριακής ανάλυσης ευστάθειας των τόξων, με παράλληλη ανάδειξη νέων υπολογιστικών διαδικασιών. Η δομή της παρουσιάζεται συνοπτικά παρακάτω. Στο πρώτο κεφάλαιο γίνεται ιστορική ανάλυση της μεθόδου μέσα από παρουσίαση και σχολιασμό των εργασιών με τη σημαντικότερη συμβολή, από τα μέσα του 17ου αιώνα μέχρι σήμερα. Στο δεύτερο κεφάλαιο επανεξετάζεται ένα από τα πιο κλασικά προβλήματα της μηχανικής: ποιο είναι το ελάχιστο επιτρεπτό πάχος ενός ημικυκλικού τόξου υπό τη δράση του ιδίου βάρους του για να είναι ευσταθές. Παράλληλα απαντώνται τα ερωτήματα που τέθηκαν παραπάνω αναπτύσσοντας νέες κλειστές μαθηματικές εκφράσεις των γραμμών ώθησης μέσω γεωμετρικής προσέγγισης, αλλά και μέσω του λογισμού των μεταβολών. Στο τρίτο κεφάλαιο χρησιμοποιείται παρόμοια διαδικασία για την ανάλυση της γενικής περίπτωσης των ελλειπτικών τόξων, οποιουδήποτε γεωμετρικού λόγου ύψος προς βάση, καθώς δεν είναι διαθέσιμα αναλυτικά αποτελέσματα στη διεθνή βιβλιογραφία, όπως συμβαίνει για τα κυκλικά τόξα. Στο τέταρτο κεφάλαιο εξετάζεται η οριακή ευστάθεια κυκλικών τόξων οποιασδήποτε γωνίας εναγκαλισμού, υπό την ταυτόχρονη δράση του ιδίου βάρους τους και σταθερής οριζόντιας εδαφικής επιτάχυνσης, ενώ υπολογίζεται με ακρίβεια η μορφή που θα έχει ο επικείμενος μηχανισμός κατάρρευσης μαζί με το οριακό πάχος, συναρτήσει της σεισμικής φόρτισης. Τα αποτελέσματα της μαθηματικής ανάλυσης (Κεφ. 2-4) επιβεβαιώνουν την ακρίβεια του λογισμικού που αναπτύχθηκε για τις ανάγκες της διατριβής, καθώς και τα αποτελέσματα που προκύπτουν από εμπορικό λογισμικό της μεθόδου των διακριτών στοιχείων. Στο πέμπτο κεφάλαιο γίνεται εφαρμογή και σύγκριση των πιο αντιπροσωπευτικών υπολογιστικών μεθόδων που απαντώνται σήμερα στη βιβλιογραφία για την αποτίμηση της ευστάθειας και φέρουσας ικανότητας της υπόγειας Θολωτής Διόδου του Σταδίου της Αρχαίας Νεμέας, ενώ η οριακή ανάλυση ευστάθειας αναδεικνύεται ως ένα μοναδικό εργαλείο για την κατανόηση της αλληλεπίδρασης της κατασκευής με το περιβάλλον έδαφος. Επιπλέων των συμπερασμάτων στο τέλος κάθε κεφαλαίου (Κεφ. 2 έως 5), στο έκτο κεφάλαιο παρουσιάζονται τα πιο σημαντικά συμπεράσματα και η συνεισφορά της παρούσας διατριβής. / This doctoral thesis revisits the limit equilibrium analysis of masonry arches. Limit equilibrium analysis is used today as the main analysis method for the assessment of the stability of masonry arches and vaulted structures, and is the outcome of important contributions that happened during the last four centuries. Although this method has a long history and a rich literature, there are still fundamental concepts that have not been thoroughly clarified, such as: What are the physically admissible thrust lines of an arch? How the stereotomy of an arch affects its limit stability? What is the role of the catenary curve (the alysoid)? Is the catenary curve a physically admissible thrust line? What is the relation between the direction of the thrust force and the slope of the thrust line at the point of application of the force? This thesis investigates these questions and aims to a better understanding of the limit equilibrium analysis of masonry arches, and at the same time, to present innovative methodologies and new analysis tools. Chapter 1 presents the work of other authors that have contributed the most to the stability analysis of masonry arches and vaulted structures over the last centuries. Chapter 2 revisits one of the most classical problems of Mechanics—what is the minimum thickness of a semicircular masonry arch subjected to its own weight. At the same time, the analysis presented in this chapter answers to the aforementioned questions through the development of closed-form expressions of the thrust line and the application of calculus of variation. Chapter 3 is focused on the limit equilibrium state of elliptical masonry arches, using the same approaches that were used in Chapter 2. This analysis was motivated from the fact that numerical results have been available in literature only for circular and not for elliptical masonry arches. Chapter 4 computes the location of the imminent hinges and the minimum thickness of circular masonry arches, for every given embrace angle, which can just sustain their own weight, together with a given level of horizontal ground acceleration. The numerical results presented in Chapters 2 to 4 confirm the accuracy of the in-house software that was developed for the needs of this thesis and the results obtained with a representative, commercially available software of the distinct element method. Chapter 5 present a comprehensive structural analysis of the Tunnel-Entrance to the Stadium of Ancient Nemea which ranges from the thrust line limit analysis and the discrete element method, to a 3-dimensional finite-element analysis. Limit equilibrium analysis emerges as a unique analysis method for the assessment of the stability of the structure and its interaction with the surrounding soil. While at the end of every chapter (Chapters 2 to 5) are presented detailed comments and conclusions, Chapter 6 is focused on outlining the most important conclusions and the main contribution of this thesis.
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MORAVSKÉ VINAŘSKÉ CENTRUM BRNO / Moravian wine centre Brno

Peková, Pavla January 2016 (has links)
This diploma thesis gives a proposal for a new Moravian wine center in the city center of Brno. Wine center is situated on the street Hlinka, where grapevines were planted in the Middle Ages. Demarcated land is narrow and elongated sloping towards to the south and connects the Yellow hills and the Brno Exhibition Centre. The main idea of this thesis is connect these two significant locations and offer the visitor a free passage along the entire length of the complex. Also main building Moravian Wine Centre reflects this fact and it expands the space of the street stalls and forms it into overgrown "arcade". The house is opened into this space - with glazed facade of the first two floors or with transmission into the rear wing. The main building consist of the cellar, where it is located wellness, winehouse, rentable wine boxes and tasting room connected with wine production. The rest of floors are designed for wine gallery, information center, reception, shop, restaurant, conference center and hotel. There is a café with roof terrace in the last floor. It offers a magnificent view into cityscape of Brno, Brno Exhibition Centre and the Yellow slope of the hill. There is designed a pond for relaxation in the courtyard. Nearby is situated Wine Institute building with facilities for making wine. In the second half of the land are located three blocks of luxury apartments in the middle of a vineyard. A leading construction is the most striking feature of the facade that reminds bougainvillea vines with vaulted arches wine cellars and attracts at first sight.

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