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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.
11

Exploration de la fonction respiratoire des patients neuromusculaires à partir d’une analyse en trois dimensions (3D) du mouvement de la paroi thoracoabdominale / Exploration of the respiratory function of neuromuscular patients from a 3D motion analysis of the thoraco-abdominal wall

Meric, Henri 17 October 2016 (has links)
Ce travail se divise en deux parties : la première partie consiste à développer et valider une technique d’exploration de la fonction respiratoire à l’aide d’outils de capture du mouvement de la cage thoracique et de l’abdomen en trois dimensions. L’innovation consiste en l’application d’une méthode de calcul des volumes pulmonaires mobilisables non encore utilisée avec cette technique. La deuxième partie consiste à mettre en évidence l’intérêt médical de cette technique par son utilisation clinique sur des pathologies respiratoires ciblées et/ou dans des conditions médicales spécifiques. Dans un premier temps et suite à une analyse de la littérature des méthodes d’exploration de la fonction respiratoire par mesure optoélectronique,nous avons proposé une nouvelle méthode de calcul des volumes respiratoires à partir de capture de mouvement de la paroi thoracoabdominale.Cette méthode prend en compte les déplacements de la surface de la paroi thoracoabdominale. Une comparaison entre cette nouvelle méthode,la méthode optoélectronique habituellement utilisée et la spirométrie(méthode de référence) montre que cette nouvelle méthode permet une évaluation précise des volumes respiratoires. Dans un second temps,une fois la question métrologique de mesure suffisamment précise des volumes validés, nous nous sommes intéressés à l’intérêt clinique d’apprécier la contribution des différents compartiments de la paroi thoracoabdominaleà la ventilation des patients myopathes et des sujets sous ventilationmécanique. Une première étude sur une population de patients présentant une déficience en maltase acide, visant l’identification du dysfonctionnement diaphragmatique a été réalisée. Ainsi nous avons pu démontrer que la contribution de la région abdominale à la ventilation est corrélée avec les indices invasifs évaluant la fonction diaphtragmatique. Cela nous permet maintenant de suivre l’évolution de la fonction diaphragmatique de ces patients de manière non invasive. Une seconde étude visait l’analyse de la contribution abdominale de la ventilation lorsque cette dernière est assistée mécaniquement. Ainsi nous avons pu observer que la ventilation mécanique diminuait la contribution abdominale, quel que soit le mode d’assistance ventilatoire utilisé, ce qui suggère une diminution de l’activité diaphragmatique sous ventilation mécanique et donc de confirmer une efficacité de ventilation mécanique. Une troisième étude sur le patient atteint de la myopathie de Duchenne de Boulogne a permis de quantifier les effets à court terme des manoeuvres d’insufflation et d’exsufflation sur la mobilité non assistée de la cage thoracique. Ainsi nous avons observé, immédiatement après ces manoeuvres, une meilleure expansion et une symétrisation de cette expansion thoracoabdominale lors d’inspirations et d’expirations maximales. Cela plaide pour une utilisation plus systématique de ces techniques au quotidien lors de la prise en charge de cette population, en particulier pour ceux qui présentent une dysharmonie du mouvement thoracoabdominal.Ce travail nous permet de proposer cette nouvelle exploration pour suivre des maladies chroniques évolutives affectant la mécanique respiratoire et l’effet des traitements spécifiques et d’envisager une application industrielle de ce nouvel outil de mesure. / This work is divided into two parts : the first part is to developand validate a technical exploration of respiratory function using motioncapturetools of the chest and abdomen in three dimensions. Innovation isthe application of a method of calculation of underlying lung volumes notyet used with this technique. The second part is to highlight the medicalinterest of this technique for clinical use in targeted respiratory pathologiesand/or specific medical conditions.First and following a literature review of methods of exploration of respiratoryfunction by optoelectronics measure we have proposed a new methodto compute respiratory volumes of motion capture of thoracoabdominalwall. This method takes into account the movements of the thoracoabdominalsurface of the wall. A comparison between this new method, optoelectronicstandard approach and spirometry (Reference method) showsthat this new method allows an accurate assessment of respiratory volumes.Secondly, once the issue of metrological sufficiently accurate measurementof volumes validated, we looked at the clinical interest of enhancing thecontribution of the different compartments of the thoracoabdominal wallin the breakdown of muscular dystrophy patients and mechanically ventilatedsubjects. An initial study on a population of patients with acid maltasedeficiency, for the identification of the diaphragmatic dysfunction was performed.Thus we have demonstrated that the contribution of the abdominalarea for ventilation is correlated with invasive indices transdiaphragmaticpressures. This now allows us to follow the evolution of diaphragmaticfunction of these patients noninvasively. A second study was the analysis ofthe abdominal contribution to the ventilation when the latter is mechanicallyassisted. Thus we have seen that mechanical ventilation decreased abdominalcontribution, whatever the method of ventilatory assistance used,suggesting a decrease in diaphragmatic activity under mechanical ventilationand thus confirm a mechanical ventilation efficiency. A third studyon the patient with Duchenne de Boulogne has quantified the short-termeffects of blowing maneuvers and exsufflation on unassisted mobility ofthe rib cage. Thus we observed immediately after these maneuvers, betterexpansion and balancing this thoracoabdominal expansion during inspirationand maximum expiration. This calls for a more systematic use of thesetechniques every day in the care of this population, particularly for thosewith disharmony of thoracoabdominal movement.This work allows us to offer this new exploration to follow evolving diseasesaffecting the respiratory mechanics and impact of specific treatmentsand to envisage an industrial application of this new measurementtool.
12

Investigating the Microquasar SS 433 and the PeVatron Candidate MGRO J1908+06 with a Novel Extended Source Analysis Method

Kleiner, Tobias Kai 10 June 2024 (has links)
Die Herkunft galaktischer sehr hochenergetischer und ultrahochenergetischer kosmischer Strahlung bleibt rätselhaft, aber Studien weisen auf zahlreiche galaktische Quellen namens PeVatrons hin, die Teilchen auf Petaelektronenvolt-Energien beschleunigen können, darunter Pulsarwindnebel, Supernovareste und Mikroquasare. Die Untersuchung der Gammastrahlung bei Giga- und Teraelektronenvolt-Energien bietet entscheidende Einblicke in ihre Eigenschaften und erweitert unser Verständnis hochenergetischer astrophysikalischer Phänomene. Diese Arbeit analysiert Daten des VERITAS-Gammastrahlenobservatoriums, bestehend aus vier 12-Meter-Tscherenkow-Teleskopen in Arizona, um ein umfassendes Verständnis von zwei galaktischen Quellen zu liefern: MGRO J1908+06, ein potenzieller PeVatron-Kandidat, und SS 433, ein Mikroquasar. MGRO J1908+06 wurde bereits in verschiedenen Wellenlängen untersucht, wobei mehrere potenzielle Ursprünge der Strahlung identifiziert wurden. Diese Arbeit führt eine umfassende Neuuntersuchung seiner ausgedehnten Gammastrahlenemissionen durch, um präzisere Abschätzungen des Gammastrahlenflusses zu liefern und frühere Ergebnisse zu aktualisieren. Die Untersuchung deutet auf einen möglichen Ursprung der Gammastrahlung sowohl aus einem Relikt eines Pulsar-Windnebels als auch aus einem neuen Pulsar-Windnebel im Feld von MGRO J1908+06 hin. Erstmals wird in den VERITAS-Daten eine signifikante Gammastrahlenemission von SS 433 festgestellt. Es werden die Gammastrahlen der Jets bei größeren Abständen und ihre Morphologie untersucht, und TeV-Spektren werden generiert. Modelle zeigen einen leptonischen Ursprung dieser Emissionen, ohne dass eine signifikante Gammastrahlenemission in der Nähe des Schwarzen Lochs oder Anzeichen für Variabilität beobachtet werden. Ausblickend präsentiert die Arbeit Untersuchungen zur Optimierung der Eigenschaften des Cherenkov-Teleskop-Array Observatoriums, mit Fokus auf die Platzierung von Illuminatoren und Abschattungseffekte zwischen Teleskopen. / The origins of galactic very-high energy and ultra-high energy cosmic rays remain elusive. Recent studies propose the existence of PeVatrons, galactic sources capable of accelerating particles to Petaelectronvolt energies, such as pulsar wind nebulae, supernova remnants, and micro-quasars. Exploring gamma-ray emission at Giga- and Teraelectronvolt energies offers crucial insights into their properties, enriching our understanding of high-energy astrophysical phenomena. This thesis focuses on analysing data from the VERITAS gamma-ray observatory, comprising four 12-meter imaging atmospheric Cherenkov telescopes in Arizona. Employing 3D maximum-likelihood analysis methods, the study aims to provide a comprehensive understanding of two extended galactic sources: MGRO J1908+06, a potential PeVatron candidate, and SS 433, a microquasar. MGRO J1908+06, though unidentified, has been scrutinized across various wavelengths, with several potential counterparts identified previously. This thesis undertakes a re-analysis of its extended gamma-ray emission, leveraging updated analysis methods and recent VERITAS observations. The improved analysis method provides a more accurate estimate of the gamma-ray flux, revising prior VERITAS flux estimates and suggesting a scenario involving both relic and new pulsar wind nebulae. Regarding SS 433, significant gamma-ray emission is detected in VERITAS data for the first time. The morphological properties of the gamma-ray emission regions seen at larger distances along the jets are examined, and their TeV spectra are constructed. Modelling supports a leptonic origin of these emissions, with no significant gamma-ray emission observed near the black hole or any indication of variability. Looking ahead, the thesis presents investigations aimed at optimizing the characteristics of the Cherenkov Telescope Array Observatory, focusing on illuminator placement and mutual shadowing effects to enhance telescope positioning within the array.
13

[en] 2D AND 3D STABILITY OF HIGH SLOPES IN AN OPEN PIT MINE / [pt] ESTABILIDADE 2D E 3D DE TALUDES DE GRANDE ALTURA EM MINA A CÉU ABERTO

JORGE GOMEZ SOTO 14 August 2019 (has links)
[pt] Esta dissertação tem como objetivo principal estudar um caso real do comportamento de taludes de grande altura em um projeto de mineração situado no Peru, em termos de deslocamentos e fatores de segurança, considerando uma escavação com uma profundidade que se aproxima de 900 m. As análises tensão x deformação foram executadas pelo método dos elementos finitos, em modelos bi e tridimensionais, considerando o modelo constitutivo de Mohr-Coulomb para os seis diferentes tipos de rocha encontrados na área do projeto. Também foram investigados os efeitos da geometria 3D em análises pseudo-estáticas, tendo em vista a mineração estar situada em região de atividade sísmica, bem como a distância da pilha de material estéril em relação à borda da escavação. De modo geral observou-se que os deslocamentos horizontais e o fator de segurança estático são maiores em analises 3D, enquanto que os deslocamentos verticais resultaram superiores nas análises 2D. Os efeitos da pilha de estéril nos valores do fator de segurança foram pouco significativos, mas a configuração da superfície potencial de ruptura varia de acordo com a distância da pilha à escavação. O fator de segurança pseudo-estático em análises 3D depende da orientação considerada para a força pseudo-estática horizontal. / [en] The main objective of this thesis is to investigate the mechanical behavior of rock slopes of great height in a mining project located in Peru, in terms of displacements and safety factors, considering that the excavation has almost reached the depth of 900m. The stress – strain analyses were carried out by the finite element method considering bi and three-dimensional models and the Mohr-Coulomb constitutive model for the six different types of rock found in the area of the project. The 3D geometrical effects on pseudo-static analyzes were also investigated, since the mine is situated in a region of seismic activity, as well as the influence of the distance of the waste material from the edge of the excavation. In general, it was observed that the horizontal displacements and the static safety factor are larger in 3D analysis while the vertical displacements were superior in 2D models. The effects of the waste dump on the values of the safety factor were insignificant, but the configuration of the potential failure surface varied according to its distance from the excavation. The pseudo-static safety factor in 3D analysis depends on the orientation considered for the horizontal pseudo-static force.
14

Investigations into orthodontic anchorage

Jambi, Safa Abdulsalam A. January 2014 (has links)
Background and objectives: The control of anchorage is integral to successful orthodontic treatment. The objective of this research was to undertake three related projects to evaluate methods of increasing anchorage with the aim of adding to orthodontic knowledge and improve methods of treatment delivery. Methods: Two Cochrane systematic reviews were undertaken according to the methods published in the Cochrane Handbook for Systematic Reviews of Interventions, version 5.1.0. The influence of functional appliances on tooth position and the extraction decision was performed as a retrospective study using participants from a completed multicentre randomized trial. Results: 1- Statistically and clinically significant differences were found between the mean values of distal molar movement when surgical anchorage and conventional anchorage were compared. 2- Statistically significant differences were found between the mean values of distal molar movement and mesial upper incisor movement when intraoral distalising appliances and cervical headgear were compared.3- Fixed and removable functional appliances are equally effective in anchorage preparation. The type of functional appliance and time spent in Phase I treatment influenced the amount of lower incisor proclination. Conclusions: 1- Surgical anchorage is more effective than headgear without the inherent risks and compliance issues. However, intraoral appliances used in adolescence for distalisation of upper molars do not appear to have any advantages over cervical headgear. 2- Functional appliances reduce the anchorage requirements of a case primarily by reduction of the overjet, both fixed and removable functional appliances are equally effective in obtaining this. However, fixed functional appliances result in greater lower incisor proclination than removable functional appliances. 3- The type of functional appliance (removable or fixed) does not influence the extraction decision, however, this is influenced by overall space requirements.
15

Systém managementu měření / Measurement management system

Aichler, Jaroslav January 2009 (has links)
The subject of diploma thesis is analysis of the European Standard EN ISO 10012, which has a status of a Czech Standard (ČSN EN ISO 10012). It’s focused on roughness measurement. The thesis was written in cooperation with a private company called PLASMAMETAL Ltd. situated in Brno. The company offers coating applications for a variety of materials. Important part of the thesis is a measurement management system improvement manual for PLASMAMETAL Ltd. It’s also dealt with the economical aspect of an investement into a new measurement equipment.
16

Biomechanical differences between elite able-bodied kayakers and elite para-kayakers during paddling : The second and third step of creating the new Paralympic classification system / Biomekaniska skillnader mellan elit kanotister utan funktionsnedsättning och elit para-kanotister vid paddling : Det andra och tredje steget av utvecklingen av det nya Paralympiska klassificeringssystemet för Parakanot

Rosén, Johanna January 2015 (has links)
Aim The aim of the study was to examine the differences between able-bodied athletes (AB) and three para-athlete (PA) classes in three-dimensional range of motion (RoM) for the major joints of the body, and to define which joint angles are correlated with power output during paddling on a kayak ergometer. An additional aim was to validate three new classification tests used in classification of Paracanoe athletes. This study was an integral part of developing a new evidence-based classification system for Paracanoe which was accepted by the International Paralympic Committee in 2015. Method 41 PA (13 F and 28 M; 35 ± 9.0 years, 70.6 ± 12.5 kg, 1.74 ± 0.12 m) and 10 AB (4 F and 6 M; 22 ± 3.5 years, 78.3 ± 10.2 kg, 1.79 ± 0.06 m) participated in the study. Three-dimensional kinematic data was recorded using an optoelectronic system containing 12 infrared cameras capturing reflective markers placed on the participants, the paddle and on the force transducers. Force was measured at the paddle to enable calculations of power output. The kinematic and kinetic data were collected during paddling on the kayak ergometer at incremental intensities starting at a low intensity level (50 W). The athletes then increased intensity with 50 W up to a high intensity level which was defined as the highest level the athlete could maintain with good technique for 20 stroke cycles. The athletes were then asked to paddle at a maximal level. The kinematic and kinetic data were imported into Visual 3D and MATLAB where all calculations were made. Results There were significant differences between the AB and the three PA classes for joint angles in the shoulder (e.g. flexion/extension and internal/external rotation, AB&gt;PA), trunk (trunk rotation and trunk flexion, AB&gt;PA) and leg (hip, knee and ankle flexion AB&gt;PA) during paddling. Significant positive correlations were seen for both men and women between power output and trunk rotation RoM, hip, knee and ankle flexion RoM and in maximal trunk flexion during paddling. A positive correlation was also seen between the newly developed classification tests and the RoM values and power output. Conclusion This study showed that the RoM of the trunk and legs are positively correlated with power output during paddling on a kayak ergometer and that there is a significant difference between the AB and the PA classes in trunk and leg RoM. The results also showed that the newly developed classification tests are valid tests to use in classification of Paracanoe athletes. / Syfte och frågeställningar Syftet med studien var att undersöka skillnaderna mellan icke funktionsnedsatta idrottare (AB) och tre klasser av funktionsnedsatta idrottare (PA) i tredimensionellt rörelseomfång (RoM) i samtliga större leder i kroppen, och att definiera vilka leder som korrelerade med power output vid paddling på kajak ergometer. Ett ytterligare syfte var att validera tre nya klassificeringstester för klassificering i Parakanot. Denna studie var en viktig del vid utvecklingen av ett nytt evidensbaserat klassificeringssystem för Parakanot vilket blev accepterat av Internationella Paralympiska Kommitteen under 2015. Metod 41 PA (13 K och 28 M; 35 ± 9.0 år, 70.6 ± 12.5 kg, 1.74 ± 0.12 m) och 10 AB (4 K och 6 M; 22 ± 3.5 år, 78.3 ± 10.2 kg, 1.79 ± 0.06 m) deltog i studien. Tredimensionell kinematisk data samlades in med ett optoelektroniskt system innehållandes 12 infraröda kameror som registrerade reflekterande markörer som var fäst på försökspersonerna, på paddeln och på kraftgivarna. Kraft mättes vid paddeln vilket möjliggjorde beräkning av power output. Den kinematiska och kinetiska datan samlades in vid paddling på kajak ergometer på olika intensitetsnivåer och idrottarna startade på en låg intensitetsnivå (50 W). Idrottarna ökade sedan intensitet med 50 W upp till en hög intensitet vilket definierades som den högsta nivån som idrottarna kunde paddla stabilt på med bra teknik i 20 drag cykler. Idrottarna paddlade sedan på en maximal nivå. Den kinematiska och kinetiska datan importerades sedan till Visual3D och MATLAB där alla beräkningar utfördes. Resultat Det fanns en signifikanta skillnader mellan AB och de tre PA klasserna för ledvinklarna i skuldran (flexion/extension och inåt/utåt rotation, AB&gt;PA), bålen (bål rotation och bål flexion, AB&gt;PA) och i benen (höft, knä och ankel flexion, AB&gt;PA) vid paddling. Det fanns en signifikant positiv korrelation för både män och kvinnor mellan power output och RoM i bål rotation, höft, knä och ankel flexion och i maximal bål flexion vid paddling. En positiv korrelation fanns även mellan de nyutvecklade klassificeringstesterna och RoM värdena samt power output. Slutsats Studien visade att bål- och benrörelsen är positivt korrelerat med power output vid paddling på kajak ergometer och att det är en signifikant skillnad mellan AB och PA klasserna i bål och ben RoM. Resultaten visade också att de nyutvecklade klassificeringstesterna är valida tester för användning inom klassificering av Parakanotister. / <p>Kursen Projektarbete.</p>
17

The prostatic tumour stroma

Bonda, Ulrich 12 August 2016 (has links) (PDF)
The majority of cancer research projects mainly focus on the epithelial cancer cell, while the role of the tumour stroma has been largely neglected. Conventional 2D techniques, such as well plates and other kinds of tissue culture plastic, and animal models are mainly used to broaden our understanding of how tumours arise, develop, and induce metastasis. However, there is accumulating evidence suggesting a tremendous impact of the non‐cancerous tumour stroma on carcinogenesis, while other publications illustrate the great importance of advanced 3D in vitro models for cancer research. The overall goal of this work was to investigate how cancer associated fibroblasts (CAFs; the most abundant component in the tumour stroma) and normal prostate fibroblasts (NPFs), isolated from patients diagnosed with aggressive forms of prostate cancer, contribute to angiogenesis, an important hallmark of cancer progression. For this purpose, a 3D in vitro angiogenesis co‐culture model was established. At first, two (semi‐) synthetic hydrogel platforms, gelatine methacrylate (GelMA) and star‐shaped (star)PEG‐heparin hydrogels were characterised and their physicochemical properties were compared with each other. Interestingly, GelMA gels shrank while starPEG‐heparin gels swelled in cell culture medium over the course of 24 hours. The cell concentration, in addition to the stiffness, was critical for the formation of endothelial networks, and the knowledge of swelling behaviour enabled the adjustment of initial cell density to ensure the density between both gel types was comparable. Moreover, preliminary tests with mesenchymal stem cells demonstrated that the hydrogel can be actively remodelled, as evaluated by stiffness parameters at day one and seven of incubation. Growth factors (GFs) affect cellular fate and behaviour, and storage, presentation and administration of such chemokines can be critical for certain cellular applications. Due to the high anionic charge density of heparin, starPEG‐heparin hydrogels are known to reversibly immobilise several GFs and thereby might mimic the GF reservoir of the extra cellular matrix. Thus, transport processes of GFs with low and high heparin affinity inside these hydrogels were analysed by fluorescence correlation spectroscopy and a bulk diffusion approach. Results indicated that diffusion constants were synergistically decreased with increasing size and heparin affinity of the diffusant. Next, the capability of endothelial cells (ECs) to self‐assemble and organise into 3D capillary networks was tested in GelMA, starPEG‐heparin and Matrigel hydrogels. Only starPEG‐heparin hydrogels allowed the formation of interconnected capillaries in macroscopic hydrogel samples. However, as it is widely used to test for pro‐ and anti‐angiogenic agents, the 2D Matrigel angiogenesis assay was included for subsequent co‐culture experiments of ECs and fibroblasts in order to investigate how the stromal cells influence the formation of endothelial networks. For a detailed characterisation of 3D structures, a conventionally applied 2D method (Maximum Intensity Projection for 3D reconstructed images, MIP) was compared to an optimised 3D analysing tool. As a result, it was discovered that MIP analysis did not allow for an accurate determination of 3D endothelial network parameters, and can result in misleading interpretations of the data set. Indirect co‐cultures of hydrogel‐embedded ECs with a 2D layer of fibroblasts showed that fibroblast‐derived soluble factors, including stromal cell‐derived factor 1 and interleukin 8, affected endothelial network properties. However, only co‐encapsulation of ECs and fibroblasts in starPEG‐heparin hydrogel discs revealed remarkable changes in endothelial network parameters between CAF and NPF samples. In detail, the total length and branching of the capillaries was increased. For two donor pairs, the diameter of capillaries was decreased in CAF samples compared to NPF samples, underlining the high physiological relevance of this model. In contrast, significant differences in 2D Matrigel assays were not detected between, CAF, NPF and control (ECs only) samples. In summary, a 3D angiogenesis co‐culture system was successfully developed and used to characterise stromal‐endothelial interactions in detail. The combination of advanced biomaterials (starPEG‐heparin) and 3D analysing techniques goes beyond conventional 2D in vitro cancer research, and opens new avenues for the development of more complex models to further improve the acquisition of more biologically relevant data.
18

Um modelo computacional para a análise global tridimensional da estrutura de edifícios altos de concreto armado com a presença de paredes estruturais / A computational model for 3D global structure analyses of high-rise reinforced concrete buildings with the consideration of shear walls

Bernardi, Douglas Francescatto January 2010 (has links)
A crescente valorização das áreas disponíveis para a construção de edifícios nas grandes cidades tem constantemente elevado a altura das edificações. Nos edifícios altos, a consideração das ações horizontais na verificação da estabilidade da construção passa a ter um caráter essencial. As ações horizontais podem ser absorvidas, basicamente, por dois sistemas estruturais: por uma estrutura composta por pórticos de grande rigidez ou pela combinação de pórticos e paredes estruturais. Dentro deste contexto, esta dissertação trata da análise tridimensional de estruturas de edifícios altos de concreto armado, considerando a presença de paredes estruturais. Ao longo do trabalho é desenvolvido um modelo computacional em linguagem FORTRAN 90, baseado no Método dos Elementos Finitos, para realizar este tipo de análise. O modelo segue as recomendações da NBR6118 (ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS, 2007). Conforme esta norma, a não linearidade física é considerada de forma simplificada pela redução da rigidez dos elementos através de um fator fixo, função do nível de fissuração esperado A não linearidade geométrica, por outro lado, pode ser considerada de maneira simplificada ou de forma exata a partir de uma formulação desenvolvida por Argyris et al. (1979). No modelo analisado, foram implementados elementos de pórtico espacial para a representação de vigas e pilares, e de casca poliédrica para as paredes e lajes. Com o objetivo de se obter um sistema computacional eficiente, são utilizados recursos como a hipótese de diafragma rígido nos pavimentos e a subestruturação. Tais recursos permitem diminuir o tamanho do problema a ser resolvido, sem, no entanto, perder precisão nos resultados. O desenvolvimento do modelo computacional permitiu uma análise crítica de casos, confrontando as duas alternativas de sistemas para edifícios altos, ou seja, de pórticos com e sem paredes estruturais. / The on going increase in value of available construction sites in big cities has steadily pushing up the height of new buildings. In high-rise buildings, the consideration of lateral loads when stability is verified gains an essential role. Basically, lateral loads can be carried out by two types of structural systems: by a structure composed of high-stiffness frames or by a combination of these frames and shear walls. In this context, this work focuses on 3D analyses of high-rise reinforced concrete buildings with the consideration of shear walls. A computational model based on the Finite Element Method is developed for the analyses, being the model described in detail in the text. The model follows the recommendations given in the Brazilian code NBR6118:2007. According to this code, physical nonlinearities are considered in a simplified manner by decreasing stiffnesses by a fixed factor, which depends on the expected level of cracking. Geometrical nonlinearities, on the other hand, could be considered either in a simplified manner or in an exact approach from the formulation developed by Argyris et al. (1979). In the developed model, spatial frame elements were implemented to represent beams and columns, while polyedric shells would represent shear walls and slabs. Targeting an efficient computational system, the rigid diaphragm hypothesis for the slabs as well as substructuring procedures were demanded strategies. Such means allowed smaller problem sizes to be solved without putting in jeopardy the results’ precision. It is also presented an analysis confronting the two alternatives of systems for high-rise building structures, i.e., frames with and without shear walls.
19

Le centre Galactique aux très hautes énergies : modélisation de l’émission diffuse et premiers éléments d’analyse spectro-morphologique / The galactic center to vers high energies : diffuse emission modeling and first elements of spectromorphological analysis

Jouvin, Lea 27 September 2017 (has links)
Le centre Galactique (GC) est une région très riche et complexe. Le taux de supernovae (SN) associé à la formation d'étoiles massives y est très élevée et devrait créer une injection continue de rayons cosmiques (CRs) dans le GC à travers les chocs qu'elles produisent. Cette région abrite également un trou noir supermassif (SMBH) de $4 \times 10^6 \, \rm{M_{\odot}}$, nommé Sgr A*. De nombreux arguments ont permis de montrer que le SMBH pouvait accélérer des particules à très haute énergie (VHE); son activité actuelle et passée pourrait donc également contribuer à la population de CRs. En 2006, la collaboration H.E.S.S. a révélé la présence d'une émission diffuse à VHE dans les 100 pc centraux de la Galaxie, très corrélée à la distribution de matière moléculaire répartie dans la zone moléculaire centrale (CMZ). Une partie importante de cette émission a donc très probablement une origine hadronique mais celle-ci reste toujours inconnue. Nous présentons une nouvelle analyse spectrale et morphologique détaillée de la région en utilisant 10 ans de prise de données de H.E.S.S. ainsi qu’une modélisation de l'émission $\gamma$ induite par les SNe. Nous étudions l'impact de la distribution temporelle et spatiale des SNe dans le CMZ sur la morphologie et le spectre de l'émission: nous construisons un model 3D d'injection de CRs à VHE et d'une propagation diffusive dans la région avec une distribution de gaz réaliste. La contribution des SNe ne peut pas être négligée. Nous montrons qu’un profil piqué de rayon $\gamma$ ainsi qu’un excès de CRs vers le GC peuvent être obtenus en utilisant une distribution spatiale réaliste de SNe prenant en compte les amas d'étoiles massives centraux. La morphologie de l'émission est très dépendante de l'énergie dans ce scénario. Le profil de densité de CRs peut également être reproduit avec une injection stationnaire unique au centre par Sgr A* mais cela implique alors une morphologie stable en énergie. L'utilisation d'une analyse 3D est donc nécessaire pour distinguer les modèles. Nous présentons les premiers résultats de cette analyse que nous avons développé dans la librairie Gammapy afin d'ajuster simultanément un spectre et une morphologie sur des données. Avec la prochaine génération d'instruments comme le Cherenkov Telescope Array, les observations de régions avec une morphologie complexe, avec une émission diffuse ou de multiples sources, vont devenir de plus en plus nombreuses. Elles nécessitent donc également le développement de cette technique. Nous détaillons les premières validations de cette méthode appliquée sur des sources ponctuelles avec un outil Monte Carlo. Pour l’émission diffuse, nous présentons le nouveau spectre obtenu en utilisant une méthode que nous avons développée pour l’extraction spectrale 1D classique. Nous réalisons par ailleurs une analyse morphologique dans différentes bandes en énergie indépendantes en utilisant de nouveaux modèles spatiaux. Pour l'instant, aucune variation significative n'est détectée mais des observations supplémentaires sont nécessaires ainsi qu'une vraie analyse 3D de la région du GC pour pouvoir donner une conclusion définitive. Les observations de CTA permettront de donner des réponses précises à ces questions. / The Galactic center (GC) is a very rich and complex astrophysical region. The high supernovae (SN) rate associated with the strong massive star formation should create a sustained cosmic rays (CR) injection in the GC via the shocks they produce. This region also harbors a Super-Massive Black Hole (SMBH) of $4 \times 10^6 \, \rm{M_{\odot}}$, named Sgr A*. Since it has been argued that the SMBH might also accelerate particles up to very high energies (VHE), its current and past activity could contribute to the CR population. In 2006, the H.E.S.S. collaboration revealed the presence of a VHE diffuse emission in the inner 100 pc of the Galaxy in close correlation with the molecular matter spread in the central molecular zone (CMZ). A major part of this emission is thus certainly of hadronic origin but it still remains mysterious. We report a new detailed spectral and morphological analysis of this region using 10 years of H.E.S.S. observations as well as a detailed modelling of the $\gamma$-ray emission induced by the SNe. We study the impact of the spatial and temporal distribution of SNe in the CMZ on the VHE emission morphology and spectrum: we built a 3D model of VHE CR injection and diffusive propagation with a realistic gas distribution. The contribution of SNe can not be neglected. We show that a peaked $\gamma$-ray profile and CR excess towards the GC, can be obtained using realistic SN spatial distribution taking into account the central massive star clusters. A strong dependence on the morphology of the emission with the energy is expected in this scenario. The CR density profile can also be reproduced by a unique stationary injection at the center by Sgr A* but it implies a stable morphology across the energy range. To distinguish the models, we need a 3D analysis. We present the first results of this analysis that we started to design in the software Gammapy to simultaneously fit a spectral and morphological model to the data. The observations of complex morphological regions with diffuse emission or multiple sources will become more and more numerous with the next generation instruments such as the Cherenkov Telescope Array. They will also require the development of this technique. We detail the first validations of this method on point sources using a Monte Carlo tool. For the ridge emission, we report the new spectrum using a method that we developed for the classical spectral fitting necessary for faint emission. By using new spatial templates to describe the complexity of the diffuse emission, we perform a morphological analysis in different energy bands independently. No significant variation is found but more observations are needed to give a conclusive statement as well as a real 3D analysis in the GC region. The observations of CTA will allow to give precise answers to these questions.
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Um modelo computacional para a análise global tridimensional da estrutura de edifícios altos de concreto armado com a presença de paredes estruturais / A computational model for 3D global structure analyses of high-rise reinforced concrete buildings with the consideration of shear walls

Bernardi, Douglas Francescatto January 2010 (has links)
A crescente valorização das áreas disponíveis para a construção de edifícios nas grandes cidades tem constantemente elevado a altura das edificações. Nos edifícios altos, a consideração das ações horizontais na verificação da estabilidade da construção passa a ter um caráter essencial. As ações horizontais podem ser absorvidas, basicamente, por dois sistemas estruturais: por uma estrutura composta por pórticos de grande rigidez ou pela combinação de pórticos e paredes estruturais. Dentro deste contexto, esta dissertação trata da análise tridimensional de estruturas de edifícios altos de concreto armado, considerando a presença de paredes estruturais. Ao longo do trabalho é desenvolvido um modelo computacional em linguagem FORTRAN 90, baseado no Método dos Elementos Finitos, para realizar este tipo de análise. O modelo segue as recomendações da NBR6118 (ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS, 2007). Conforme esta norma, a não linearidade física é considerada de forma simplificada pela redução da rigidez dos elementos através de um fator fixo, função do nível de fissuração esperado A não linearidade geométrica, por outro lado, pode ser considerada de maneira simplificada ou de forma exata a partir de uma formulação desenvolvida por Argyris et al. (1979). No modelo analisado, foram implementados elementos de pórtico espacial para a representação de vigas e pilares, e de casca poliédrica para as paredes e lajes. Com o objetivo de se obter um sistema computacional eficiente, são utilizados recursos como a hipótese de diafragma rígido nos pavimentos e a subestruturação. Tais recursos permitem diminuir o tamanho do problema a ser resolvido, sem, no entanto, perder precisão nos resultados. O desenvolvimento do modelo computacional permitiu uma análise crítica de casos, confrontando as duas alternativas de sistemas para edifícios altos, ou seja, de pórticos com e sem paredes estruturais. / The on going increase in value of available construction sites in big cities has steadily pushing up the height of new buildings. In high-rise buildings, the consideration of lateral loads when stability is verified gains an essential role. Basically, lateral loads can be carried out by two types of structural systems: by a structure composed of high-stiffness frames or by a combination of these frames and shear walls. In this context, this work focuses on 3D analyses of high-rise reinforced concrete buildings with the consideration of shear walls. A computational model based on the Finite Element Method is developed for the analyses, being the model described in detail in the text. The model follows the recommendations given in the Brazilian code NBR6118:2007. According to this code, physical nonlinearities are considered in a simplified manner by decreasing stiffnesses by a fixed factor, which depends on the expected level of cracking. Geometrical nonlinearities, on the other hand, could be considered either in a simplified manner or in an exact approach from the formulation developed by Argyris et al. (1979). In the developed model, spatial frame elements were implemented to represent beams and columns, while polyedric shells would represent shear walls and slabs. Targeting an efficient computational system, the rigid diaphragm hypothesis for the slabs as well as substructuring procedures were demanded strategies. Such means allowed smaller problem sizes to be solved without putting in jeopardy the results’ precision. It is also presented an analysis confronting the two alternatives of systems for high-rise building structures, i.e., frames with and without shear walls.

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