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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.
471

Effets biomécaniques des implants interépineux lombaires / Biomecanical effects of interspinous lumbar devices

Khiami, Frédéric 19 December 2013 (has links)
En pathologie lombaire dégénérative, [des] procédures chirurgicales peuvent être employées pour répondre aux situations clinicoradiologiques rencontrées. Ces procédures sont efficaces mais invasives et grevées d'un taux de complications non négligeables. Les dispositifs interépineux (DIE) [diminuent] ainsi la morbidité. Cependant leur efficacité est controversée. Les effets des DIE peuvent être appréciés sur la modification cinématique de l'étage implanté et sur la modification de la taille des foramens. A travers une série d'études biomécaniques cadavériques, les auteurs tentent de vérifier s'il existe bien ces effets attendus avec 4 dispositifs différents. Concernant L4, DIAM® et In-Space® n'avaient aucun effet contrairement à Wallis qui avait un effet significatif en flexion et en extension. Concernant L5, aucun implant n'avait d'effet en flexion, alors que tous avaient un effet amortissant en extension. Il n'y avait pas d'implant supérieur aux autres. Concernant les variations de mobilité, Wallis® est l'implant qui diminue le plus les amplitudes globales de L4 et L5, de l'ordre de 50% et 42.7%, respectivement. […] Une étude cadavérique de la surface latérale du foramen intervertébrale par méthode photographique et binarisation des images a permis de montrer qu'avec le YODA, la longueur moyenne du foramen était de 15.7±2.8mm et la largeur moyenne de 9.4±1.2mm. Après implantation des DIE, ces dimensions variaient respectivement à 16.8±2.5mm et 10.1±1.3mm. La surface foraminale moyenne était de 150.4±35.8 mm2 à vide et de 165.1±28.3mm2, après implantation. Le gain moyen était de 14.7mm2 (5.3-26.9). Cependant, cet implant n'avait aucun effet sur la cinématique de l'étage implanté, même en extension, justifiant de discuter une modification de sa structure. La mesure stéréoscopique 3D des variations de surface foraminale L4-L5 et des foramens adjacents a permis de montrer que tous les implants ouvrent le foramen L4-L5 en extension. Deux catégories d'implants : 1 qui ouvrent le foramen en position neutre, en flexion et en extension ; 2 qui ferment le foramen en flexion mais l'ouvrent en extension. La mise en place des implants en L4-L5 n'avait aucune conséquence sur la taille du foramen à l'étage L3-L4. En revanche, XSTOP et DIAM entraînaient une fermeture minime du foramen L5-S1 vers l'extension. La mesure de surface nous a semblé insuffisante pour évaluer la globalité de la sténose. Nous avons développé une nouvelle mesure de la taille du foramen en appréciant son volume au scanner. Avec cette technique de mesure, le volume moyen de 60 foramens et de 20 foramens L4-L5 étaient respectivement de 1.17±0.23 et de 1.25±0.27 mm3 pour l'observateur 1 et de 1.21±0.21 et 1.29±0.23 mm3 pour l'observateur 2. Les CIC intra observateurs pour l'observateur 1 pour la mesure de l'ensemble des foramens et pour L4-L5 étaient de 0.98 et 0.99. Pour l'observateur 2, les CIC étaient de 0.90 et 0.92, respectivement. Les CIC inter observateurs pour l'observateur 1 pour la mesure de l'ensemble des foramens et pour L4-L5 étaient de 0.78 et 0.83. Pour l'observateur 2, les CIC étaient de 77 et 0.8. La moyenne des différences de mesures entre les observateurs étaient de moins de 0.2 mm3 (0.05 and 0.15). […] L'excellente reproductibilité de cette mesure simple complète les outils de mesure de la taille du foramen. La validation de cette mesure du volume a permis de vérifier s'il y avait ou pas, une variation du volume foraminal après implantation comparative des quatre dispositifs inter épineux. Les volumes des foramens L4-L5 étaient significativement augmentés après implantation de INSPACE®, XSTOP® et WALLIS®. Le volume foraminal moyen de l'étage sus jacent n'était pas modifié et seul le WALLIS® diminuait le volume en L5-S1. XSTOP® : l’implant qui ouvrait le plus les foramens. Les dispositifs interépineux ont bien des effets biomécaniques sur l'étage implanté, aussi bien en cinématique que sur les variations de la taille du foramen intervertébral. / In lumbar degenerative disease, many surgical procedures can be used to respond to different radiological clinical situations. These invasive procedures are effective, but with a significant complication rate. Interspinous devices (DIE) are positioned with more limited approaches, thereby reducing morbidity. However, their effectiveness is controversial. The effects of EIS can be evaluated on the kinematic changes of the implanted level and changing in the foramina size. Through a series of cadaveric biomechanical studies, the authors try to check if these are good effects expected with 4 devices. Concerning L4, DIAM® and In-Space® had no effect on either flexion or extension, contrary to Wallis®, which had a significant effect on flexion and extension. Concerning L5, no implant had an effect in flexion, while all presented a significant amortisation effect on extension.No significant difference was revealed between implants on flexion, in extension or on a global cycle. Concerning the mobility variations, Wallis® is the implant which decreases the global average movement of L4 and L5 the most, by 50% and 42.7%, respectively.The analysis of variations in the size of foramina is still confidential. Few authors are concerned. A cadaver study of the lateral surface of the intervertebral foramen by photographic method and binarization images has shown that with YODA, the average length of foramen was 15.7 ± 2.8mm and the average width of 9.4 ± 1.2mm. After implantation of DIE, these dimensions ranged respectively 16.8 ± 2.5mm and 10.1 ± 1.3mm. The mean foraminal area was 150.4 ± 35.8 mm2 vacuum and 165.1 ± 28.3mm2 after implantation. The average gain was 14.7mm2 (5.3-26.9). However, this implant has no effect on the kinematics of the implanted level even in extension justifying discuss a modification of the implant. Stereoscopic 3D measuring foraminal area variations on L4-L5 level and adjacent foramina has shown that all implants open the L4-L5 foramen in extension. There seems to be two types of implants: those who open the foramen in neutral, flexion and extension, and those who close the foramen bending but open to extension. There were no effects on the size of the foramen L3 -L4. However, Xstop and DIAM resulted minimal closure L5-S1 foramen to the extension. Surface measurement seemed insufficient to assess the totality of the stenosis. We developed a new measure of the foramen size enjoying its volume scanner. With this measurement technic, the mean volume of 60 foramen and 20 L4-L5 foramen were respectively 1.17 ± 0.23 and 1.25 mm 3 ± 0.27 for the observer 1 and 1.21 ± 0.21 and 1.29 ± 0.23 mm 3 for the observer 2. The intra observer CIC 1 for the observer for all measuring foramina and L4 - L5 were 0.98 and 0.99, respectively. For observer 2, ICC were 0.90 and 0.92, respectively. The inter-observer CIC for the observer 1 for measuring all foramina and L4 - L5 were 0.78 and 0.83, respectively. For observer 2, the CIC were 77 and 0.8, respectively.The average differences in measurements between observers were less than 0.2 mm3 (0.05 et 0.15). This is the first study to measure the volume of the foraminal scanner. The excellent reproducibility of this simple measure complements the tools to measure the size of the foramen. The validation of this volume measurement was used to check whether or not there was a change in the foraminal volume after comparative implementation of four interspinous devices. L4-L5 foramina volumes were significantly increased after implantation of InSpace ®, Xstop ® and WALLIS ®. The average volume of the underlying foraminal volume was not changed and only WALLIS ® decreased the volume L5 -S1. Interspinous devices have many biomechanical effects on the implanted level, as well as kinematic changes in the size (area and volume) of the intervertebral foramen. They have no impact on adjacent
472

Longitudinální výzkum růstu dětí ve středních Čechách a Praze s přihlédnutím k vývoji v rámci prvního stupně školní docházky / Longitudinal Study of Children Growth in Central Bohemia and Prague with Respect to the Development of Passing Basic School Education

Povinská, Monika January 2019 (has links)
For my dissertation, I have chosen to monitor and research growing children in Prague and in the Central Bohemian Region. Primarily, I am interested in the growth period of the younger school age (which corresponds to the first degree of compulsory school attendance). However, I also monitored and worked with the growth data of infant and pre-school aged children. The reason for this is that I needed the growth data from a longer period of time for a better assessment. I am really interested in the area of child anthropology because I belive the growth of every child is essential for their future. The final height and weight of the individual, specifically his/her total body proportions, can have a significant influence on their next life. I am convinced that this can have a major influence on the health, social application and self-confidence for each of us. Thanks to a very willing approach of a Prague pediatrician I managed to accumulate the growth data of children living in Prague. I would like to compare the obtained data with the data of children living in the Central Bohemian Region. I was able to gain the growth data of the children thanks to the friendly cooperation of my pupils'parents, my acquaintances and friends. Children were selected according to their health cards. On these cards...
473

Mesures du périmètre crânien dans les troubles envahissants du développement : une étude comparative entre adultes

Nguyen, Anh Kiet Danny 02 1900 (has links)
No description available.
474

Vliv individuálních vlastností samců páskovce kroužkovaného (Cordulegaster boltonii) na jejich epigamní chování / Golden-ringed Dragonfly (Cordulegaster boltonii): Effect of individual male characteristics on their epigamic behavior

Rohlíková, Barbora January 2018 (has links)
My study researches the individual male characteristics of Cordulegaster boltonii in relation to their epigamic behavior. The first part of this study analyzes the relations of the measured characteristics (length and height of the wing, wings area, body weight, age), in the second part I assess their possible effect on the epigamic behavior of males of Cordulegaster boltonii, specifically how they affect the intensity of searching for females. Males of this species perform distinctive scanning flights over a stream to find an ovipositing female to mate with her. I used individually marked males to quantify their performance which can be interpreted as reproductive success because more active males are more likely to meet and mate females. My work includes 3 methods of evaluating activity. The first is based on the actual number of flights, the second on the average daily order of the males (based on the number of flights in days when the males have been seen). The third method combines the average daily order with number of days when the males could be seen. In the second part of the study I evaluate the effect of the above-mentioned individual characteristics on the flight activity of males. The outcome of the GLM indicates that the only characteristic with significant effect is the age of the...
475

Investigation of Emission Source Heights in FLEXPART 10.02 for the Wildfire in Pedrógão Grande, Portugal, 2017 / Undersökning av utsläppshöjder i FLEXPART 10.02 för skogsbranden i Pedrógão Grande, Portugal, 2017

Nygren, Anton January 2019 (has links)
One of the worst wildfires in Portugal in 2017 on June17- 21 started at the central part of Pedrógão Grande and spread fast to the surrounding areas Góis, Pampilhosa da Serra and Arganil. The wildfire took 64 lives and a large smoke plume was observed. The interest in smoke plumes from wildfires is partly due to their emitting of greenhouse gases (CO2), a large source of aerosols, CO, oxides of nitrogen and other trace gases that can affect the air quality at local and regional scale. The regional scale can be affected because the smoke from wildfires can get elevated and be transported into the free troposphere and the lower stratosphere by either pyro convection or radiative driven convection and can be transported long distances, for example from Canada to Germany. This thesis investigates how the emission source height in a model affects the transport of the smoke plume and compares the simulations with observations. Observations of transport of emissions from wildfires are often done with satellites and in this thesis data from the second modern-era retrospective analysis for research and applications (MERRA2) is used as the observations. In this thesis the numerical model FLEXPART 10.02 is used to calculate the transportation of CO from the wildfire in Pedrógão Grande. The altitude of the emission source top height and bottom height in FLEXPART was changed to see how it affected the smoke plume in the simulation. The agreement between plumes from the observations and the simulation plumes were calculated with the structural similarity (SSIM) index and the change of SSIM index was investigated. The results were that the best similarity for horizontal images was with an emission source height of 100- 300 m, for vertical images at 40°N with an emission source height 0- 1500 m and for vertical images at 41°N with an emission source height 100- 1200. The overall best simulation was the simulation with emission source height 100- 1200 m (average of the three similarity calculations). Some uncertainty occurs in the results due to for example differences in resolutions between MERRA2 and FLEXPART and the weather condition may have contributed. To improve the results there is a need to compare simulations with more wildfires to see that the SSIM index behaves the same. / En av de värsta skogsbränderna i Portugal 2017 var den 17–21 juni och började i centrala Pedrógão Grande och spred sig snabbt till de omgivande områdena Góis, Pampilhosa da Serra och Arganil. Skogsbranden tog 64 liv och stora rökplymer observerades. Rökplymer från skogsbränder är intressanta därför att de bland annat är en källa av växthusgaser till exempel koldioxid (CO2), aerosoler, kolmonoxid (CO) och andra spårgaser som kan påverka luftkvaliteten på lokal och regional skala. Den regionala skalan kan påverkas eftersom rök från skogsbränder kan sprida sig upp till den fria troposfären och den nedre stratosfären med konvektion. Konvektion är när luften blir varm av olika skäl och stiger, luften kyls av när den stiger och blir då tyngre och till slut sjunker luften. Det som kan driva konvektion vid en brand är branden själv och strålning och kan transportera röken från branden långa avstånd, till exempel från Kanada till Tyskland. Den här uppsatsen undersöker hur utsläppshöjden (mellan vilka höjder röken släpps ut från) påverkar transporten av rök och jämför beräkningarna med observationer. Observationer av transport av utsläpp från bränder sker ofta med satelliter och i denna uppsats används data från en återanalys av en samling observationer från MERRA2 (the second modern-era retrospective analysis for research and applications) som observationer. En återanalys är ett dataset som räknas med en modell från i tid och rum oregelbundna observationer från historiska och nutida data. I denna uppsats används den numeriska transportmodellen FLEXPART 10.02 för att beräkna transport av kolmonoxid från skogsbranden i Pedrógão Grande. Höjden av utsläppskällans topphöjd och bottenhöjd i FLEXPART ändrades för att se hur det påverkat rökplymen i simuleringen. Likheten mellan rökplymen från observationerna och simuleringarna beräknades sedan med ett test kallat SSIM och förändringen av SSIM indexet undersöktes. Resultaten var att den bästa simuleringen för de horisontella bilderna med en utsläppshöjd på 100– 300 m, för de vertikala bilderna på 40°N en utsläppshöjd på 0– 1500 m och för de vertikala bilderna på 41°N en utsläppshöjd på 100– 1200 m. Totalt sett (medelvärde från de tre simuleringarna) hade emissions höjden 100- 1200 m den bästa likheten med observationerna. Det finns en osäkerhet i resultaten på grund av tillexempel att det är olika upplösning i MERRA2 och FLEXPART och att väderförhållanden kan ha påverkat beräkningarna. För att förbättra resultatet så kan man göra simuleringar av fler skogsbränder för att se om SSIM indexet uppför sig densamma.
476

Estratégias de suplementação energética para bovinos em recria em pastagens tropicais durante as águas e seus efeitos na terminação em confinamento / Energetic supplementation strategies for growing cattle grazing tropical forages during the raining season and their effects on the feedlot finishing phase.

Agostinho Neto, Luiz Roberto Dell 26 October 2010 (has links)
Os objetivos deste estudo foram avaliar estratégias de suplementação energética para bovinos em recria, mantidos em pastagens tropicais bem manejadas durante as águas, quanto ao desempenho animal, capacidade de suporte das pastagens, ganho de peso por área e desempenho dos animais durante a terminação em confinamento. Os tratamentos testados foram: T1) Controle: somente mistura mineral; T2) Constante: fornecimento contínuo do concentrado na dose de 0,6% do PC; T3) Crescente: fornecimento de 0,3% do PC em concentrado no primeiro terço, 0,6% do PC no segundo terço e de 0,9% do PC no terceiro terço do período de recria dos animais. Foram utilizados 76 garrotes de corte, com peso inicial de 208 kg e 8 meses de idade. Os animais foram alocados em 8,5 ha de pastagem de capim Brachiaria brizantha cv. Marandu, manejados em sistema rotacionado com intervalo de desfolha variável. Foram avaliadas a massa de forragem (MF) pré e pós pastejo (kg MS ha-1), a composição morfológica (% de folhas, colmos e material morto) e valor nutritivo da forragem, o ganho de peso individual (kg cab-1 dia-1), a taxa de lotação (cab ha-1) e o ganho de peso por área (kg ha-1) durante a fase de recria dos animais. Na fase de confinamento dos animais foram avaliados o ganho de peso diário individual (GPD em kg cab-1), o consumo de matéria seca (kg dia-1) e a eficiência alimentar dos animais (kg de ganho diário kg de alimento consumido-1).Os animais suplementados apresentaram GPD superiores aos animais não suplementados (0,535, 0,787 e 0,867 kg cab-1 dia-1, respectivamente para os tratamentos controle, constante e crescente). Além disso, os animais do tratamento crescente apresentaram desempenho superior àquele dos animais do tratamento constante, mesmo consumindo quantidades semelhantes de suplemento. A suplementação foi, ainda, eficiente em aumentar a taxa de lotação dos pastos que foi, em média, de 5,94, 7,13 e 6,90 UA ha-1, respectivamente para os tratamentos controle, constante e crescente. Durante a fase de confinamento, não houve diferença entre os tratamentos para GPD, que apresentou média de 1,06 kg dia-1. A suplementação energética de bovinos durante a fase de recria em pasto é uma estratégia eficaz para aumentar o GPD dos animais, a taxa de lotação das pastagens e a produção de carne por área de pasto. / The objective of this study was to evaluate the effect of strategies of feeding an energetic supplement to growing cattle, grazing well managed tropical pastures during the rainy season, on the grazing animal performance, pasture stocking rate, total body weight gain per area, and on feedlot finishing phase. The treatments tested were: T1) Control: animals fed only a mineral mixture; T2) Constant level: constant daily feeding of energetic supplement at 0.6% of BW; T3) Increased level: daily feeding of energetic supplement at increasing levels of 0.3, 0.6, and 0.9% BW, according to the experimental period. Seventy six beef steers, averaging 208 kg BW and 8 months of age, were used. Animals were allocated in a 8.5 ha area of Brachiaria brizantha cv. Marandu pasture under a rotational grazing system with a variable defoliation interval. Pre- and post-grazing forage mass (FM, kg MS ha-1), morphological composition (leaves, stem, and dead material percentages), nutritive value of the forage, average daily gain (kg animal-1 day-1), stocking rate (animal ha-1), and weight gain per area (kg ha-1) were evaluated during the growing phase. At the feedlot phase were evaluated the average daily gain (kg animal-1 day-1), dry matter intake (kg day-1), and the gain to feed ratio. Supplemented animals had greater ADG than animals not supplemented (0.535, 0.787, and 0.867 kg animal-1 day-1), respectively for the control, constant, and increasing treatment levels. Furthermore, animals in the increasing supplementation group presented a highest performance when compared to the constant supplementation, although animals from both treatments have consumed similar amount of supplement. Supplementation also was efficient in improving the pasture stocking rate, which averaged 5.94, 7.13, and 6.90 AU ha-1, respectively for the control, constant, and increasing treatment levels.During the feedlot phase, there were no ADG differences among any treatment, which averaged 1.06 kg day-1. DMI and feed efficiency were also not affected by supplementation strategies during the grazing phase.
477

Redução de energia e suplementação de xilanase em dietas de poedeiras de 02 a 80 semanas de idade / Reduction of energy and xylanase supplementation in diets of laying hens from 02 to 80 weeks

Souza, Karina Márcia Ribeiro de 27 October 2011 (has links)
A utilização de enzimas como aditivos alimentares para poedeiras comerciais pode aumentar a digestibilidade dos nutrientes dos ingredientes da dieta. Assim, o objetivo do trabalho foi avaliar os efeitos da suplementação de enzima xilanase em dietas de poedeiras comerciais à base de milho e soja sobre desempenho, morfologia intestinal e incremento de energia da dieta. Foram utilizadas 400 poedeiras da linhagem Hy-line, variedade W36 com duas semanas de idade submetidas às dietas experimentais até as 80 semanas de idade. As aves foram distribuídas em delineamento inteiramente casualisado em esquema fatorial 2x2 (nível de energia x inclusão de xilanase), totalizando 4 tratamentos com 10 repetições de 10 aves cada. Os tratamentos foram: controle positivo (dieta balanceada para respectiva idade); controle positivo+xilanase; controle negativo (dieta com redução de 100 kcal/kg no nível de EM); controle negativo+xilanase. Nas fases de cria e recria (2 a 6 e 7 a 17 semanas), foram realizadas as avaliações para peso corporal, ganho de peso, consumo de ração, conversão alimentar, viabilidade criatória e uniformidade do lote. As seis e 16 semanas foram colhidos fragmentos de intestino das porções duodeno, jejuno e íleo para mensurações de altura de vilo e profundidade de cripta. Durante a fase de postura (18 a 80 semanas) foram avaliadas características de desempenho (ganho de peso, consumo de ração, produção, peso e massa de ovos, conversão alimentar e viabilidade criatória). Foram realizados ainda, quatro ensaios de digestibilidade (14, 36, 60 e 80 semanas) para determinação da energia metabolizável aparente e energia metabolizável aparente corrigida das dietas e coeficientes de metabolizabilidade dos nutrientes. Conclui-se que a suplementação de xilanase em dietas de poedeiras com redução de 100 kcal/kg de energia metabolizável promove melhor formação da mucosa intestinal e o fornecimento de dietas com níveis de energia adequados associadas à suplementação de xilanase proporciona valores de energia metabolizável (EMA) e energia metabolizável corrigida (EMAn) superiores em relação aos valores obtidos com dietas sem suplementação de enzima para fase de postura. Além disso, a adição de xilanase em dietas de poedeiras comerciais, a base de milho e soja possibilita a redução do nível de energia da dieta sem prejudicar o desempenho das aves. / The use of enzymes as feed additives for laying hens can increase the digestibility of nutrients present in diet. Thus, the objective was to evaluate the effects of xylanase enzyme supplementation in diets of laying hens based corn and soybean on performance, gut morphology and increased energy diet. Were used 400 layers of Hy-line W36 with two weeks of age fed experimental diets until 80 weeks of age. The birds were distributed to a completely randomized design in a 2x2 factorial (including energy level x xylanase), totaling four treatments with 10 replicates of 10 birds each. The treatments were: positive control (balanced diet to the age), positive control + xylanase, negative control (diet with a reduction of 100 kcal/kg ME) and negative control + xylanase. In phase of rearing (2 to 6 and 7 to 17 weeks), evaluations were made for body weight, weight gain, feed intake, feed conversion, livability and uniformity. At six and 16 weeks were collected fragments intestine of portions duodenum, jejunum and ileum for measurement of villus height and crypt depth. During the laying phase (18 to 80 weeks) were evaluated performance characteristics (weight gain, feed intake, production, weight and egg mass, feed conversion and livability). Were also conducted four assays of digestibility (14, 36, 60 and 80 weeks) to determine the apparent metabolizable energy and apparent metabolizable energy corrected, coefficients of metabolization of diet nutrients. It was concluded that supplementation xylanase in diets of laying hens with reduction of 100 kcal/kg of metabolizable energy promotes better formation of the intestinal mucosa and compensates for the reduction of dietary energy, providing metabolizable energy and feeding diets with energy levels associated with adequate supplementation of xylanase provide values metabolizable energy and corrected metabolizable energy above to the values obtained with diets without supplementation enzyme to the production phase. Furthermore, the addition of xylanase in diets for laying hens, based corn and soybeans, allows reduction in the level of dietary energy without damaging the performance of birds.
478

Movimento de malhas e remalhamento de malhas superficiais / Mesh motion and surface remeshing

Soares, Igor Prata 08 February 2007 (has links)
Malhas dinâmicas são comumente utilizadas em problemas de simulação sobre dominios cuja geometria varia com o tempo. Sempre que o domínio onde a malha está definida é alterado, as molas são acionadas movimentando os vértices para que estes se conformem com a nova descrição do domínio. Os tipos de molas mais utilizadas são: as longitudinais, as torcionais e as semi-torcionais. Nesta tese uma nova mola é proposta, a mola altura, que além de evitar sobreposição de elementos, é conceitualmente simples e fácel de ser implementada. Outra contribuição desse trabalho é o mecanismo de vértices ativos, que permite economia de processamento durante a resolução da malha dinâmica. Quando a fronteira do domínio sofre grandes alterações, o processo dinâmico pode não ter êxito na correção da malha. Para contornar esse problema, a fronteira deve ser alterada aos poucos. Uma nova estratégia para realizar grandes deformações em pequenos passos é introduzida nesta tese. Em algumas aplicações, o movimento da fronteira da malha pode comprometer células da própria fronteira. A correção da fronteira e um processo delicado, já que em muitos casos ele implica em alterar a descrição do domínio. Um novo método para efetuar a correção da fronteira é apresentado neste trabalho. Ele é baseado em malhas dinâmicas e utiliza um novo conceito de molas, as molas conservativas. Todas as contribuições citadas acima tiveram aplicação prática na industria aeronáutica, sendo utilizadas na implementação de uma metodologia inovadora para acoplar um simulador de escoamento de fluidos tridimensional com uma ferramenta de projeto inverso de aerofólios que roda em um contexto bidimensional. O outro assunto abordado e o remalhamento de triangulações superficiais. Foi proposto um novo método, chamado ANTS (Anisotropic Triangulations on Surfaces) que produz triangulações anisotrópicas de qualidade sobre superfícies descrevendo objetos com geometria complexa. O método ANTS é caracterizado por efetuar o remalhamento diretamente na triangulação inicial, isto é, ele não faz uso de qualquer tipo de parametrização, seja global ou local. O processo de remalhamento é feito por meio de quatro operadores: inserção, remoção e movimento de vértices e alternância de arestas. Os operadores de inserção e remoção de vértices possibilitam controlar a densidade de vértices no domínio, permitindo que nós sejam inseridos em regiões com densidade baixa ou eliminados onde a densidade é alta. A qualidade dos triângulos é controlada por meio dos operadores de movimento de vértices e de alternância (flipping) de arestas. O operador de movimento é utilizado no núcleo do processo de remalhamento. Para evitar que o remalhamento danifique a forma original da superfície, as quinas e os córneres são detectados no inicio do processo e preservados durante o remalhamento. A densidade de vértices sobre o domínio é controlada por uma função de espalhamento. Tal função pode ser passada como entrada para o ANTS ou calculada pelo próprio método. O ANTS foi aplicado com êxito em diversos exemplos gerando malhas de boa qualidade / This thesis intends to make a contribution on the field of dynamic meshes. Dynamic meshes are commonly used in the simulation of problems on domains whose geometry varies in time. Virtual springs are placed in the mesh to rearrange its vertices whenever the domain is changed. The most commonly used types of springs are: longitudinal, torsional and semi-torsional. In this thesis a new type of spring is introduced, the height spring, that is conceptually simple but produces good results. Another contribution of this thesis is the active vertices mechanism, that can improve the CPU processing time of the dynamic mesh. When the mesh domain undergoes large deformations, the proposed dynamic mesh algorithm may fail in correcting the mesh. A solution to this problem is perform large deformations in smal steps. A new strategy for this purpose is presented. Sometimes the motion of the mesh boundary can damage cells on the boundary itself. This is a trick problem to solve since the correction of boundary might change the domain geometry. A new method to correct the boundary cells is also presented in this study. The method is based on the dynamic mesh concept and uses a new type of spring, the conservative spring. All the mentioned contributions had been applied in the aeronautics industry. The techniques developed here has been used to implement an innovative methodology to couple a three-dimensional fluid dynamic solver with a two-dimensional inverse design tool for airfoils. This thesis also deals with remeshing. It is presented the ANTS, a practical method for remeshing anisotropic triangulations on surfaces of complex geometry. The method is capable of performing refinement and coarsening during the same process using the well-known remeshing operators: vertex motion, vertex deletion (by collapsing edges), vertex insertion, and edge flipping. An interesting feature is that vertex motion is used in the core of the process instead of in a post-processing smoothing step. The ANTS uses the input mesh as the geometrical description and works directly on the surface mesh without using any other auxiliary structure (besides the input mesh itself) to preserve the geometrical shape. Moreover, neither global nor local parameterization are applied. Sharp edges and points are identified at the beginning and kept during the process in order to preserve ridges and details. The method has been successfully applied to several examples producing high quality meshes
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Acúmulo e valor nutritivo da forragem do capim Convert HD 364 (Brachiaria híbrida) sob taxas contrastantes de crescimento em resposta à altura do dossel mantida por lotação contínua / Forage accumulation and nutritive value of Convert HD 364 (Brachiaria hybrid) under contrasting growth rates in response to canopy height maintained by continuous stocking

Almeida, Ianê Correia de Lima 13 October 2014 (has links)
As pastagens ocupam uma grande extensão territorial no Brasil constituindo a principal fonte de alimento para os ruminantes. Entretanto, seu manejo, ainda é frequentemente realizado de forma extensiva e extrativista, tornando a atividade pouco competitiva. O estudo de estratégias de manejo do pastejo sob lotação contínua contribui para a diversificação e intensificação dos sistemas de produção de ruminantes baseados em pastagens. O objetivo foi descrever e explicar diferenças no potencial produtivo e nas características qualitativas, através de atributos estruturais e químico-bromatológicos da Brachiaria híbrida (Brachiaria ssp.) Convert HD 364 em resposta ao manejo do pastejo sob lotação contínua mimetizada e taxa de lotação variável. O experimento foi conduzido em Piracicaba, no verão de 2013. Foram testadas três intensidades de desfolhação determinadas por alturas de manejo de dossel (10, 25 e 40 cm) em combinação com dois ritmos de crescimento (50 e 250 kg N ha-1 ano-1) num arranjo fatorial (3 x 2) e delineamento em blocos completos casualizados. Variáveis-resposta medidas incluíram massa, acúmulo e taxa de acúmulo de forragem, IAF, composição morfológica e valor nutritivo (Proteína bruta - PB, Fibra insolúvel em detergente neutro- FDN, Digestibilidade in vitro da matéria orgânica - DIVMO) da forragem. Os maiores valores de acúmulo e taxa de acúmulo foram registrados para os dosséis mantidos a 40 cm de altura (12650 kg MS ha-1ano-1 e 110 kg MS ha-1 dia-1, respectivamente) e para dosséis adubados com 250 kg N ha-1(13974 kg MS ha-1ano-1 e 126 kg MS ha-1dia-1, respectivamente). Esse mesmo tratamento apresentou os maiores valores de IAFs (8,1). A massa de forragem não sofreu influência do N, mas respondeu ao aumento da altura e foi maior para os pastos mantidos a 40 cm (14650 kg MS ha-1). Mais N (250 kg ha-1) resultou em maior proporção de folhas (26 %). Maior proporção de colmo (40%) ocorreu no dosséis de 40 cm e adubados com 50 kg N ha-1 e proporções de material morto foram maiores (49%) nos tratamentos de 10 cm de altura e 50 kg de N ha-1. Dosséis de 10 cm adubados com 50 kg N ha-1, embora com menor produtividade, resultaram em maior DIVMO (670 g kg-1) e PB (153 g kg-1 e 165 g kg-1, para 10 cm e 250 kg N ha-1, respectivamente). O teor de FDN foi maior para 40 cm (545g kg-1) e com 50 kg N ha-1(550 g kg-1). A adubação nitrogenada promove ganhos em produtividade e resulta em forragem com melhor valor nutritivo, enquanto que incrementos em altura do dossel promovem maior acúmulo total e taxa média de acúmulo de forragem, até o ponto em que ocorre estabilidade da produção (25 cm), sendo assim o tratamento que apresentou melhor eficiência produtiva aliada a um bom valor nutritivo foi o com 25 cm de altura do dossel e 250 kg ha-1 de N. / Pastures occupy a large area in Brazil and are key to the country\'s livestock industry, which is almost exclusively forage-based. Grazing management, however, is largely empirical in the country, and technical guidelines for managing specific grasses are either scarce or poorly adopted, which hinders the competitiveness of the activity. Establishing sound management guidelines for key grasses can improve animal output and profitability of the livestock enterprise. The objective was to describe and explain differences in the productive potential and the qualitative traits of Convert HD 364 brachiariagrass through the characterization of agronomic and sward structural attributes as well as forage nutritive in response to three grazing intensities and under two growth rates under continuous stocking and variable stocking rate in a mob-grazing experimental protocol. The study was conducted in Piracicaba, in summer of 2013. Experimental paddocks received treatments corresponding to all possible combinations among three sward heights (10, 25, and 45 cm) and two growth rates generated by two N rates (50 and 250 kg N ha-1) split-applied monthly during the experimental period. The experimental design was a randomized complete block with a factorial arrangement. Response variables included forage accumulation and accumulation rate, LAI, plant-part composition of forage on offer, as well as plant-part composition and nutritive value (crude protein - CP, neutral detergent insoluble fiber - NDF digestibility in vitro organic matter - IVDMD) of forage. The highest values of forage accumulation and accumulation rate were recorded for swards kept at 40 cm (12650 kg DM ha-1 yr-1 and 110 kg ha-1 d-1, respectively) and for swards fertilized with 250 kg N ha-1 (13974 kg DM ha-1 yr-1 and 126 kg DM ha-1 day-1, respectively). This same combination resulted the highest LAI (8.1). Forage mass was affected by sward height but not by N rates being higher for 40-cm (14650 kg DM ha-1). Treatments with higher N (250 kg ha-1) resulted in forage with a higher proportion of leaf (26%). Higher percentages of stem (40%) were measured in swards grazed at 40 cm and fertilized with 50 kg N ha-1 while the proportion of dead material was higher (49%) in 10-cm swards receiving 50 kg N ha-1 of N. Swards kept at 10 cm and receiving 50 kg N ha-1, although less productive, resulted in forage with higher IVOMD (670 g kg-1). Forage in 10-cm swards had 153 g kg-1 crude protein and that from swards receiving 250 kg N ha-1 had 165 g kg-1. Neutral detergent fiber concentration was higher in forage from 40-cm swards (545 g kg-1) and from those receiving 50 kg N ha-1 (550 g kg-1), which is also associated with the maturity of the tissues at the time of harvest. Nitrogen fertilization promotes gains in productivity and results in forage with better nutritive value, whereas increases in canopy height promote higher total accumulation and rate of herbage accumulation, up to 25 cm. The treatment that combines high productivity with high nutritive value is 25 cm canopy height and 250 kg ha-1.
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Compensação tamanho/densidade populacional de perfilhos em pastagens de Cynodon spp. / Tiller size/population density in grazed swards of Cynodon spp.

Sbrissia, André Fischer 02 March 2000 (has links)
O presente experimento foi conduzido no Departamento de Produção Animal da ESALQ/USP, em Piracicaba (SP), entre 15/12/98 e 04/07/99. Os tratamentos foram constituídos pelas combinações entre três cultivares de Cynodon spp. (Tifton-85, Florakirk e Coastcross) e quatro alturas de pasto (5, 10, 15 e 20 cm) mantidas por pastejo de ovinos em regime de lotação contínua e taxa de lotação variável. O delineamento experimental utilizado foi o de blocos completos casualizados em arranjo de parcelas subdivididas com quatro repetições. As parcelas corresponderam aos cultivares e as subparcelas (unidades experimentais) às alturas de pasto. Foram analisadas as seguintes variáveis: biomassa na área total, densidade populacional de perfilhos, massa por perfilho, massa de folha por perfilho e área foliar por perfilho. A partir dessas medições foram realizados cálculos de índice de área foliar do pasto (IAF), volume por perfilho, relação folha:haste por perfilho e relação área foliar:volume por perfilho (R). O mecanismo de compensação tamanho/densidade populacional de perfilhos operou em pastagens de Cynodon spp.. No entanto, as inclinações das retas foram consistentemente maiores que a proposição teórica de 3/2. Perfilhos individuais de Cynodon spp. apresentaram um padrão de crescimento isométrico e parecem agruparse em clones para assegurar estratégia competitiva e otimização de IAF. Pastos mantidos a 5 cm durante o outono apresentaram densidades populacionais reduzidas, indicando um padrão de tolerância ao pastejo dependente da época do ano. Tifton-85 e Coastcross apresentaram uma capacidade de aumento em biomassa que pode ir além da altura de 20 cm, enquanto que para o cultivar Florakirk essa capacidade situou-se em torno de 20 cm. O estádio reprodutivo das plantas interferiu de forma significativa nos processos de competição intra-específica e dinâmica populacional de perfilhos. / The experiment was conducted at the Department of Animal Production, ESALQ/USP, Piracicaba (SP), from 15/12/98 until 04/07/99. Treatments were combinations of three Cynodon spp. cultivars (Tifton-85, Florakirk and Coastcross) and four sward surface heights (SSH) (5, 10, 15 and 20 cm) maintained by sheep under continuous stocking and variable stocking rate. A complete randomised block design was used, with treatments arranged in split-plot and replicated four times. Grass cultivars were assigned to plots and SSH to sub-plots. Pastures responses evaluated were: total biomass above ground level, tiller population density, tiller weight, leaf mass and leaf area per tiller. From these measurements calculations of sward leaf area index (LAI), tiller volume, tiller leaf:stem ratio and tiller leaf area:volume ratio (R) were derived. A tiller size/population density mechanism operated in Cynodon spp. However, a slope steeper than the theoretical expectation of 3/2 was observed. Individual tillers presented an isometric pattern of growth and seemed to demonstrate a clonal integration among tillers in order to enhance competitive ability and optimise LAI. Swards maintained at 5 cm during autumn presented reduced tiller population densities, indicating a pattern of grazing tolerance dependent of time of the year. Tifton-85 and Coastcross pastures showed a capacity to increase total biomass that could go beyond 20 cm, while Florakirk stabilised around that SSH. Reproductive development of plants interfered with the processes related to intra-specific competition and tiller population dynamics.

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