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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

Analysis of the AASHTO LFRD Horizontal Shear Strength Equation

Lang, Maria Weisner 21 November 2011 (has links)
The composite action of a bridge deck and girder is essential to the optimization of the superstructure. The transfer of forces in the deck to the girders is done across a shear interface between the two elements. The transfer occurs through the cohesion of the concrete at the interface and then through the shear reinforcement across the interface. Adequate shear strength is essential to the success of the superstructure. A collection of 537 horizontal shear tests comprised the database for the study of various concrete types and interface surface treatments. The predicted horizontal shear strength calculated from the AASHTO LFRD bridge design code was compared to the measured shear strength. The professional bias was computed for each specimen. The professional biases, standard deviations, and coefficients of variation for each category were calculated. The material properties factor along with fabrication factor was researched. The loading factors were researched and calculated for use in calculating the reliability index. The final step was to compute the reliability index for each category. The process was repeated to learn the reliability of the equation proposed by Wallenfelsz. The results showed that the reliability index for the AASHTO LRFD horizontal shear strength equation wash much lower than the desired target reliability index of 3.5. The reliability index for the Wallenfelsz equation was higher but still not close to the target reliability index. / Master of Science
12

Endossimbionte Wolbachia em moscas-das-frutas do gênero Anastrepha (Tephritidae) e em vespas parasitóides (Braconidae) associadas / Endosymbiont Wolbachia in fruit flies (Tephritidae) and in associated parasitoid wasps (Braconidae)

Mascarenhas, Rodrigo de Oliveira 04 May 2007 (has links)
Amostras, de oito espécies de moscas-das-frutas do gênero Anastrepha e de seis espécies de vespas (Braconidae) parasitóides à elas associadas, coletadas em diferentes localidades do Brasil, foram estudadas para uma detecção e caracterização das linhagens da bactéria endossimbionte Wolbachia. A detecção e identificação de Wolbachia foram feitas pela amplificação e seqüenciamento de um fragmento do gene wsp (Wolbachia “surface protein"). As seqüências obtidas foram comparadas com seqüências depositadas no GenBank mostrando que todos os fragmentos amplificados e seqüenciados eram realmente provenientes de Wolbachia. Das espécies de Anastrepha, infecção pela Wolbachia foi encontrada em A. amita, A. obliqua, A. macrura, A. montei, A. picklei, A. sp.1 aff. fraterculus e A. sp.2 aff. fraterculus, exceto na amostra de A. serpentina. Dentre as seis espécies e braconídeos estudados, apenas as duas amostras de Asobara Anastrephae e uma amostra de Opius bellus, não apresentaram infecção. Já as oito amostras de Doryctobracon areolatus, duas de D. brasiliensis, uma de D. fluminensis, três de Opius bellus e cinco de Utetes Anastrephae apresentaram-se infectadas por essas bactérias. Foram identificadas 21 linhagens distintas de Wolbachia, sendo oito mais divegentes e as demais apresentando pequenas variações. Duas amostras de A. obliquaestavam infectadas com mais de uma linhagem de Wolbachia, enquanto que as demais espécies de Anastrepha abrigavam apenas uma linhagem da bactéria. Entre os braconídeos, quatro amostras populacionais de U. Anastrephae e uma de D. brasiliensis apresentaram múltipla infecção, enquanto que as demais espécies exibiram apenas uma única linhagem de Wolbachia associada. Foram detectadas linhagens distintas da bactéria entre diferentes amostras de uma mesma espécie, assim como, uma mesma linhagem bacteriana está presente em populações de mais de uma espécie do himenóptero. U. Anastrephae foi detectada parasitando quatro diferente espécies de Anastrepha, tendo sido observado que a mesma linhagem de Wolbachia que infectava as moscas-das-frutas também infectava o parasitóide. Além disso, a análise filogenética indicou que as bactérias Wolbachia que infectam os braconídeos aqui estudados exibem uma alta similaridade com linhagens presentes em insetos não relacionados taxonomicamente mas que, em alguns casos, habitam regiões neotropicais. O conjunto de resultados sugere que eventos de transferência horizontal das bactérias entre esses insetos possam ter ocorrido. / Detection and characterization of infection by the bacteria Wolbachia were done in samples of eight species of the fruit fly Anastrepha and six species of their parasitoid wasps (Braconidae), collected in several localities in Brazil. The presence and identification of the Wolbachia strains were performed by amplificaton and sequencing of a fragment of the Wolbachia wsp gene. Comparisions of the sequences with the data on the GenBank confirmed that the amplified fragment were from Wolbachia. The endosymbiont was found in Anastrepha amita, A. obliqua, A. macrura, A. montei, A. picklei, A. sp.1 aff. fraterculus e A. sp.2 aff. fraterculus, but not in the sample of A. serpentina. Among the six species of braconids only samples of Asobara Anastrephae and one sample of Opius bellus were not infected. The eight samples of Doryctobracon areolatus, two of D. brasiliensis, one of D. fluminensis, three of Opius bellus and five of Utetes Anastrephae were infected by these bacteria. Twenty one distinct strains of Wolbachia were detected, eight of which having a higher level of distinctiveness than the others, which showed slight variation. Two out of the four samples of Anastrepha obliqua were infected by more than one strain of Wolbachia, while a single strain of bacteria was found in the other Anastrepha species. Among the braconids, four samples of U. Anastrephae and one sample of D. brasiliensis showed multiple infection, and single strains of Wolbachia were found in the other species of parasitoids. It was found that a same strain of Wolbachia may be present in different host species, either fruit fly or the parasitoids, as well as, that the same host species may present different strains of bacteria. The braconid U. Anastrephae was found parasiting four different species of Anastrepha, and in every case and samples, the same Wolbachia strain was found in both, the fruit fly and its parasitoid. Moreover, a phylogenetic analysis indicated that the Wolbachia strains infecting the fruit flies and the parasitoid wasps here studied showed a high similarity to strains present in other phylogentic non-related insects, some of which inhabiting neotropic regions. The data suggest that horizontal transfer of Wolbachia might have occurred in these two groups of insects.
13

A Modified Genetic Algorithm Applied to Horizontal Well Placement Optimization in Gas Condensate Reservoirs

Morales, Adrian 2010 December 1900 (has links)
Hydrocarbon use has been increasing and will continue to increase for the foreseeable future in even the most pessimistic energy scenarios. Over the past few decades, natural gas has become the major player and revenue source for many countries and multinationals. Its presence and power share will continue to grow in the world energy mix. Much of the current gas reserves are found in gas condensate reservoirs. When these reservoirs are allowed to deplete, the pressure drops below the dew point pressure and a liquid condensate will begin to form in the wellbore or near wellbore formation, possibly affecting production. A field optimization includes determining the number of wells, type (vertical, horizontal, multilateral, etc.), trajectory and location of wells. Optimum well placement has been studied extensively for oil reservoirs. However, well placement in gas condensate reservoirs has received little attention when compared to oil. In most cases involving a homogeneous gas reservoir, the optimum well location could be determined as the center of the reservoir, but when considering the complexity of a heterogeneous reservoir with initial compositional variation, the well placement dilemma does not produce such a simple result. In this research, a horizontal well placement problem is optimized by using a modified Genetic Algorithm. The algorithm presented has been modified specifically for gas condensate reservoirs. Unlike oil reservoirs, the cumulative production in gas reservoirs does not vary significantly (although the variation is not economically negligible) and there are possibly more local optimums. Therefore the possibility of finding better production scenarios in subsequent optimization steps is not much higher than the worse case scenarios, which delays finding the best production plan. The second modification is developed in order to find optimum well location in a reservoir with geological uncertainties. In this modification, for the first time, the probability of success of optimum production is defined by the user. These modifications magnify the small variations and produce a faster convergence while also giving the user the option to input the probability of success when compared to a Standard Genetic Algorithm.
14

Endossimbionte Wolbachia em moscas-das-frutas do gênero Anastrepha (Tephritidae) e em vespas parasitóides (Braconidae) associadas / Endosymbiont Wolbachia in fruit flies (Tephritidae) and in associated parasitoid wasps (Braconidae)

Rodrigo de Oliveira Mascarenhas 04 May 2007 (has links)
Amostras, de oito espécies de moscas-das-frutas do gênero Anastrepha e de seis espécies de vespas (Braconidae) parasitóides à elas associadas, coletadas em diferentes localidades do Brasil, foram estudadas para uma detecção e caracterização das linhagens da bactéria endossimbionte Wolbachia. A detecção e identificação de Wolbachia foram feitas pela amplificação e seqüenciamento de um fragmento do gene wsp (Wolbachia “surface protein”). As seqüências obtidas foram comparadas com seqüências depositadas no GenBank mostrando que todos os fragmentos amplificados e seqüenciados eram realmente provenientes de Wolbachia. Das espécies de Anastrepha, infecção pela Wolbachia foi encontrada em A. amita, A. obliqua, A. macrura, A. montei, A. picklei, A. sp.1 aff. fraterculus e A. sp.2 aff. fraterculus, exceto na amostra de A. serpentina. Dentre as seis espécies e braconídeos estudados, apenas as duas amostras de Asobara Anastrephae e uma amostra de Opius bellus, não apresentaram infecção. Já as oito amostras de Doryctobracon areolatus, duas de D. brasiliensis, uma de D. fluminensis, três de Opius bellus e cinco de Utetes Anastrephae apresentaram-se infectadas por essas bactérias. Foram identificadas 21 linhagens distintas de Wolbachia, sendo oito mais divegentes e as demais apresentando pequenas variações. Duas amostras de A. obliquaestavam infectadas com mais de uma linhagem de Wolbachia, enquanto que as demais espécies de Anastrepha abrigavam apenas uma linhagem da bactéria. Entre os braconídeos, quatro amostras populacionais de U. Anastrephae e uma de D. brasiliensis apresentaram múltipla infecção, enquanto que as demais espécies exibiram apenas uma única linhagem de Wolbachia associada. Foram detectadas linhagens distintas da bactéria entre diferentes amostras de uma mesma espécie, assim como, uma mesma linhagem bacteriana está presente em populações de mais de uma espécie do himenóptero. U. Anastrephae foi detectada parasitando quatro diferente espécies de Anastrepha, tendo sido observado que a mesma linhagem de Wolbachia que infectava as moscas-das-frutas também infectava o parasitóide. Além disso, a análise filogenética indicou que as bactérias Wolbachia que infectam os braconídeos aqui estudados exibem uma alta similaridade com linhagens presentes em insetos não relacionados taxonomicamente mas que, em alguns casos, habitam regiões neotropicais. O conjunto de resultados sugere que eventos de transferência horizontal das bactérias entre esses insetos possam ter ocorrido. / Detection and characterization of infection by the bacteria Wolbachia were done in samples of eight species of the fruit fly Anastrepha and six species of their parasitoid wasps (Braconidae), collected in several localities in Brazil. The presence and identification of the Wolbachia strains were performed by amplificaton and sequencing of a fragment of the Wolbachia wsp gene. Comparisions of the sequences with the data on the GenBank confirmed that the amplified fragment were from Wolbachia. The endosymbiont was found in Anastrepha amita, A. obliqua, A. macrura, A. montei, A. picklei, A. sp.1 aff. fraterculus e A. sp.2 aff. fraterculus, but not in the sample of A. serpentina. Among the six species of braconids only samples of Asobara Anastrephae and one sample of Opius bellus were not infected. The eight samples of Doryctobracon areolatus, two of D. brasiliensis, one of D. fluminensis, three of Opius bellus and five of Utetes Anastrephae were infected by these bacteria. Twenty one distinct strains of Wolbachia were detected, eight of which having a higher level of distinctiveness than the others, which showed slight variation. Two out of the four samples of Anastrepha obliqua were infected by more than one strain of Wolbachia, while a single strain of bacteria was found in the other Anastrepha species. Among the braconids, four samples of U. Anastrephae and one sample of D. brasiliensis showed multiple infection, and single strains of Wolbachia were found in the other species of parasitoids. It was found that a same strain of Wolbachia may be present in different host species, either fruit fly or the parasitoids, as well as, that the same host species may present different strains of bacteria. The braconid U. Anastrephae was found parasiting four different species of Anastrepha, and in every case and samples, the same Wolbachia strain was found in both, the fruit fly and its parasitoid. Moreover, a phylogenetic analysis indicated that the Wolbachia strains infecting the fruit flies and the parasitoid wasps here studied showed a high similarity to strains present in other phylogentic non-related insects, some of which inhabiting neotropic regions. The data suggest that horizontal transfer of Wolbachia might have occurred in these two groups of insects.
15

Utilização de perfil geofísico de densidade e de imagem de densidade associada a algoritmos de aumento de contraste para estimativa de Net Pay em poços horizontais / Use of density well log and density image logo associated with constrast enhancement algorithms to estimate Net Pay in horizontal wells

Correa Neto, Darcy, 1979- 25 August 2018 (has links)
Orientador: Alexandre Campane Vidal / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências / Made available in DSpace on 2018-08-25T17:39:31Z (GMT). No. of bitstreams: 1 CorreaNeto_Darcy_M.pdf: 10780036 bytes, checksum: a9e1aeacd891517e00b449caddbeb578 (MD5) Previous issue date: 2014 / Resumo: A exposição de um poço horizontal à formações geológicas perfuradas ocorre de forma diferente a exposição de um poço vertical à mesma formação. O poço horizontal atravessa as camadas geológicas de forma sub-paralelas, expondo estas camadas com uma extensão maior do que os poços verticais, que as atravessam de forma sub-perpendicular, formando exposições abruptas. Essa diferença de exposição afeta os perfis volumétricos, os perfis que compõe uma média dos 360º do poço, considerando um corte perpendicular a direção longitudinal do poço de forma diferente em relação aos perfis azimutais. Devido a esta diferença na exposição, é importante considerar métodos diferentes para a estimativa de Net Pay entre poços verticais e horizontais. Assim sendo, o objetivo deste trabalho foi o de utilizar perfis de densidade azimutais para diferenciar as estimativas de Net Pay. Para a consecução dos objetivos deste trabalho, foram feitos dois estudos. O primeiro deles consiste na utilização de perfis azimutais de densidade para gerar diferentes cálculos do Net Pay. Um segundo estudo compreendeu a análise de diferentes algoritmos de aumento de contraste de imagem, para auxiliar na identificação das feições geológicas, auxiliando na análise de Net Pay. Os perfis utilizados para a realização deste trabalho são de um poço produtor de óleo perfurado em um turbidito da costa leste brasileira. Neste poço, foi possível identificar algumas feições geológicas, como arenitos e folhelhos (camadas), cimentação carbonática e falha geológica. Como resultado do cálculo de Net Pay dos diferentes perfis de densidade analisados neste trabalho, foi possível identificar uma diferença de até 10,72% de Net Pay no mesmo poço. O Net Pay final das curvas de densidade volumétrica, densidade up, densidade down, conjunto da densidade up ou down e imagem obtiveram os seguintes resultados respectivamente: 88,42%, 91,44%, 89,86%, 96,62% e 99,14%. Quanto aos algoritmos de aumento de contraste, foram aplicados 14 algoritmos do domínio do espaço, possibilitando uma melhor visualização de contatos geológicos, falhas e camadas geológicas. Entre todos os algoritmos utilizados, os que apresentaram melhores resultados em imagem de densidade foram os algoritmos de derivada de 2ª ordem, corte dos níveis de cinza e histograma normalizado. Conclui-se portanto, que cada feição geológica encontrada ao longo do poço afeta os perfis azimutais e a imagem de densidade de forma diferente, portanto, a utilização dos diferentes perfis e dos algoritmos de aumento de contraste de imagem podem deflagar quais curvas de densidade devem ser utilizadas em determinadas profundidades do poço para obter o Net Pay mais preciso / Abstract: Drilled geological formation exposure are different considering horizontal and vertical wells. A horizontal well passes throught geological beds almost parallel, resulting in a wider exposure of the formation along the well path, while vertical wells passes through the same formation perpendicularly, resulting in abrupt contact between beds. This difference in exposure affects the volumetric well logs, logs that are composed by the average of the 360º of the well, considering a perpendicular cut of the longitudinal direction of the well. Due to this difference in exposure, it is important to consider difernet methos of estimation of Net Pay regarding vertical and horizontal wells. The objective os this work is to use azimuthal density logs to make diferent Net Pay estimations. To achieve the objectives of this project, two studies were made. The first study consists of the use of azimuthal density logs to generate diferent Net Pay estimations. The second, consists of the analysis of different image contrast enhancement algorithms to help on the identification of geological features, supporting the Net Pay analysis. The logs used on this work are from an oil productive well drilled in turbidites of the brazilian east coast. In this well, it was possible to identify a few geological features, such as sandstone and shale (beds), carbonate ciment and geological faults. As a result of the Net Pay calcualtion of the diferent density logs, it was possible to identify a difference of up to 10.72% Net Pay in the same well. The final Net Pay estimated from the volumetric density, up density, down density, up or down density and density image was respectively: 88.42%, 91.44%, 89.86%, 96.62% e 99.14%. Regarding the image contrast enhancement algorithms, 14 diferent algorithms from the space domain were applied to the selected density image, allowing a better visualization of several geological features, such as geological contacts, beds and faults. The algorithms that presented the best results in this image were the 2nd order derivative, gray level slicing and normalized histogram. Conclusions of this project are that each geological feature located at the well, affects the azimuthal and image logs in different ways, so, the use of different logs and image contrast enhancement algorithms can identify which density curves should be used in different depths of the well in order to obtain the most accurate Net Pay / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo
16

Hydrodynamic loading of catenary mooring lines

Kitney, Neil January 2000 (has links)
No description available.
17

Toward a general curvilinear model for nearly-horizontal flows in two horizontal dimensions

Rodenhuis, G. S. January 1984 (has links)
No description available.
18

Interactions and Implications of a Collector Well with a River in an Unconfined Aquifer with Regional Background Flow

Dugat, William D., IV 14 January 2010 (has links)
Ranney radial collector wells consist of an array of horizontal lateral wells arranged radially around and connected to the base of a vertical well. They offer numerous advantages over traditional vertical wells with application in both the petroleum industry and hydrologic sciences. This study improved the understanding of the interaction of collector wells and the aquifers/reservoirs they tap by numerically modeling flux exchanges between a collector well and a river in an unconfined aquifer with regional background flow. Modeling demonstrated that flux along each horizontal lateral increased with distance from the vertical well stem following a third order polynomial function. Ultimately these models demonstrated that in the collector well/aquifer/river system, the pumping rate of the collector well was the dominant factor in controlling flux between the river and aquifer under various conditions. This study can be used to project the maximum allowable pumping rate without causing an initially gaining river to become a losing river.
19

Interactions and Implications of a Collector Well with a River in an Unconfined Aquifer with Regional Background Flow

Dugat, William D., IV 14 January 2010 (has links)
Ranney radial collector wells consist of an array of horizontal lateral wells arranged radially around and connected to the base of a vertical well. They offer numerous advantages over traditional vertical wells with application in both the petroleum industry and hydrologic sciences. This study improved the understanding of the interaction of collector wells and the aquifers/reservoirs they tap by numerically modeling flux exchanges between a collector well and a river in an unconfined aquifer with regional background flow. Modeling demonstrated that flux along each horizontal lateral increased with distance from the vertical well stem following a third order polynomial function. Ultimately these models demonstrated that in the collector well/aquifer/river system, the pumping rate of the collector well was the dominant factor in controlling flux between the river and aquifer under various conditions. This study can be used to project the maximum allowable pumping rate without causing an initially gaining river to become a losing river.
20

Mechanics of selected parallel bar and horizontal bar stunts in gymnastics

Ikeda, Katsunori January 1975 (has links)
The purpose of this study was to describe and compare the mechanical similarity and difference of the peach basket and the backward free hip circle by use of numerical and graphical expressions through cinematographic analysis.Sixteen millimeter motion pictures were taken of performances by four male gymnasts. Parameters such as shoulder and hip angles, trajectories of the total body’s centers of gravity, radii of the total body’s rotation, and total body’s angular velocity and acceleration, moment of inertia and angular momentum were derived.The trajectories of the total body’s centers of gravity on the peach basket and the free hip circle were found similar. The free hip circle was associated with less shoulder flexion than the peach basket, and the more frequent change of the hip flexion and extension was found on the peach basket than on the free hip circle. The free hip circle to handstand possessed larger amount of angular momentum at the ascent phase because of the larger amount of moment of inertia with the longer rotational radius (and larger amount of time of the arm pull) than the peach basket.The free hip circle could possibly be a direct introductory stunt for a gymnast to acquire the kinesthetic senses involved in the peach basket, but it would not be utilized to acquire the advanced skills of the peach basket, because the peach basket requires more complicated and different muscle movements in its successful execution.

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