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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.
1

Analysis of human physical vulnerability using static equilibrium techniques of a Hazard flood for the determination of unsafe areas in the city of Catacaos - Piura, Peru

Carrizales, J. A., Rodas, M. C., Castillo, L. F. 06 January 2022 (has links)
Heavy rains and El Nio phenomenon are recurring natural phenomena at a national level. These can cause floods due to the overflowing of rivers, which, when close to cities, can cause both human and material losses. The district of Catacaos, located in the city of Piura, was the one with the highest number of injuries due to the flood caused by El Nio phenomenon in 2017. This phenomenon causes a large amounts of rainfalls due to the presence of abnormally warm waters along the northern coast of Peru [1]. It is for this reason that the need arose to carry out an analysis of the physical vulnerability due to instability of people through static equilibrium, in said district, in order to present maps of unsafe areas in the face of this phenomenon. In this investigation, flood hazard maps are generated simulating the one presented in 2017, using 2D hydraulic modeling. For the generation of vulnerability curves, the instability analysis is performed by moment and drag force. Finally, maps with unsafe areas are made using ArcGis software. Where the results obtained indicate that 29.37% of the city was flooded. Likewise, the vulnerability maps generated show us that women and men over 18 years of age in the city of Catacaos would be vulnerable to dragging and overturning in the face of floods in 16.54% and 13.21%, respectively, of the total studied area. This information will be useful for the development of future evacuation plans during floods, carried out by national entities. © Published under licence by IOP Publishing Ltd.
2

Establishing a Coastal Protection and Planning System in Taiwan

Yu, Meng-Jiuan 05 September 2011 (has links)
In the last few decades, academic and institutions advanced in coastal research in Europe and America have rigorously engaged in developing numerical models for coastal wave hydrodynamic simulations. The notable products include MIKE21 from DHI in Denmark, CEDAS (with GENESIS and SBEACH) from Veri-Tech in the United States, and the SMC from University of Cantabria in Spain. Among them, the Spanish Coastal Modeling System (SMC) is the only integrated package for coastal planning and modeling. With a unique preprocess module which pre-stores the bathymetry and wave data, the SMC provides a user-friendly interface directly using the screen display for a series of coastal planning and design applications which comprise artificial nourishment with headland-bay beach, breakwater construction and extension, and dredging of navigation channel etc., as well as the usual wave-current simulation for countermeasures in coastal protection and disaster mitigation. Despite the availability of several numerical programs for wave-current simulations and beach changes that have been developed by the coastal professional in Taiwan, and the continuous effort of the Water Resources Agency, Ministry of Economic Affairs to establish a national coastal database, it is imperative to develop/setup an integrated bathymetry-hydrodynamics-protection system, such as the Spanish SMC, as the key element in the national platform for coastal planning and modeling. This dissertation first describes the coastal environment in Taiwan, major causes for shoreline evolution and then reviews the history of shore protection since 1970s, together with the current prospective for coastal environment and strategies to sustain the natural shoreline ratio. To accomplish these goals, the Water Resources Agency has endeavored to implement artificial nourishment with headland-bay beaches, in order to raise the ratio of natural shoreline, in addition to establish a national coastal planning and simulation platform. As a response to this call for eco-engineering approach, we recommend that headland-bay beach in static equilibrium be adopted for mitigating coastal erosion, beach restoration and creation of recreational beaches, which can be designed directly on the screen using the empirical bay shape equation in conjunction with the SMC. Based on the framework of the Spanish SMC, this writer has successfully attempted the preliminary pre-process module of Baco (bathymetry) and Odin (wave climate) for Taiwan, using data from digitized nautical charts, nearshore depth surveys, and long-term wave observation results around Taiwan from the International Comprehensive Ocean-Atmosphere Data Set (ICOADS). The effort generates the first version of SMC in Taiwan. Having pre-stored the bathymetry and wave data for Dapeng bay in Pingtung County and Sizihwan Bay in Kaohsiung City, a series of coastal planning and modeling procedures for these two model sites are demonstrated in this dissertation, including a series of calculations of wave-current distribution for monsoon and storm waves, as well as planning of bay beach using artificial nourishment. Upon executing the Taiwanese version of SMC introduced in this dissertation, the modeling results can be applied to assist the planners and decision makers in comprehending the coastal environment, devising a feasible shore protection strategy, and promoting an earlier accomplishment of the so-called ¡ugeo-engineering ¡u in our country. Finally, the writer also wishes the outcome of this study could help relevant government agency to accomplish the prospective of sustainable coastal development upon implementing the strategies of establishing an appropriate coastal planning platform and promoting a systematic approach for coastal planning and design, as revealed in the "Sustainable Regeneration of Coastal Environment Project (98 ~ 103 fiscal year)".
3

The effects of scaling on bite force and suction index in the eastern hellbender (Cryptobranchus alleganiensis)

Larghi, Nicholas Patrick 01 January 2013 (has links)
The hellbender (Cryptobranchus alleganiensis) is a salamander that grows over a large range of body sizes (2-74 cm total length) making it an ideal organism for examining the effects of body size on morphology and performance. The goal of this study is to investigate the morphology changes over ontogeny and change in feeding ability. Cryptobranchus feeds on small aquatic insects as juveniles and shifts to crayfish as they get larger. Morphology can be expected to change as an organism grows larger, and because morphology and performance are closely linked, this morphological change can result in a change in feeding ability. Cryptobranchus alleganiensis are primarily aquatic salamanders that utilize both suction feeding and biting behaviors. I hypothesize bite force would increase with positive allometry reflecting a possible dietary shift during ontogeny in which larger Cryptobranchus favor crayfish. Because suction is the primary mode of feeding making it an important aspect of feeding throughout ontogeny, suction index was hypothesized to scale with isometry. Fourteen preserved specimens (11.9-34.5 cm SVL) were used to investigate the effects of scaling on suction potential and estimated bite force. Bite force was calculated using a 3D static equilibrium model and suction potential was calculated as suction index. Bite force scaled with positive allometry allowing the animals to bite harder relative to body mass with increasing body size, and suction index showed no effect of body size. Results of this study indicate that Cryptobranchus alleganiensis maintains suction performance across ontogeny allowing them to generate suction with similar ability ontogenetically, but increases its biting performance to cope with durophagous prey with a possible ontogenetic dietary shift.
4

Stress Analysis of Ramberg-Osgood and Hollomon 1-D Axial Rods

Giardina, Ronald J, Jr 17 May 2013 (has links)
In this paper we present novel analytic and finite element solutions to 1-D straight rods made of Ramberg-Osgood and Hollomon type materials. These material models are studied because they are a more accurate representation of the material properties of certain metals used often in manufacturing than the simpler composite linear types of stress/strain models. Here, various types of loads are considered and solutions are compared against some linear models. It is shown that the nonlinear models do have manageable solutions, which produce important differences in the results - attributes which suggest that these models should take a more prominent place in engineering analysis.
5

Vector tugs actuation modeling for ship maneuvering simulators. / Modelagem da atuação de rebocadores vetoriais para simuladores de manobras marítimas.

Barrera, Rodrigo Domingos 02 May 2019 (has links)
Ship Manoeuvring Simulators have proved to be powerful tools on analyzing the feasibility of new maritime maneuvers and new port constructions. In order to provide a complete immersive and real environment, such simulators must correctly represent the dynamics of the controlled vessel as well as the actuation of the tugboats, which have been extremely used over the last years due to the increasing complexity on the maritime maneuvers. Although few simulators can correctly model the dynamics of the tugboats, they still represent their actuation through the so-called \"vector tug model\". This is usually the case because it is expensive to run several integrated-simulators in real-time and the simulator centers do not have trained tugboat captains available. The vector tugs are usually represented as simplified external forces actuating on a vessel. The simplicity of such models causes a loss of realism during a maritime simulation due to the fact that neither the forces exerted on a towed vessel nor the tugboat\'s actuation position are accurate. In addition, tugboats\' actuation response time is usually not taken into account under the current vector tug models used on Ship Manoeuvring Simulators. The main objective of this work is to provide an innovative approach for vector tug actuation modeling in such a way that the towing force magnitude and actuation positions are accurate either in push or pull operation modes. The author will expand the static equilibrium model for tugboat force prediction presented in Brandner (1995) and Artyszuk (2014) and combine it along with optimization techniques in order to accurately obtain the tugboats\' actuation either working under the direct maneuver (i.e., tugboat uses solely its propeller power in order to exert force on a towed vessel) or working under the indirect maneuver (i.e., tugboats use the environmental disturbances and the hull drag in order to maximize their actuation force on a towed vessel). The implementation of the new mathematical model provides a new level of reality when vector tugs are used in Ship Manoeuvring Simulators. / Simuladores Navais têm provado ser poderosas ferramentas, tanto na análise de viabilidade de novas manobras portuárias, quanto na construção de novos portos. De modo a conseguir criar um ambiente imersivo e realista, tais simuladores devem conseguir representar corretamente a dinâmica de um navio a ser controlado e a atuação dos rebocadores portuários no mesmo. Embora alguns simuladores consigam modelar corretamente a dinâmica de rebocadores portuários, eles ainda representam tal atuação utilizando o modelo comumente chamado de \"rebocadores vetoriais\". Tal fato normalmente acontece pois é muito caro utilizar diversos simuladores conectados em tempo real. Além disso, em muitas ocasiões, os centros de simulação não têm disponível um comandante de rebocador treinado e capaz de manusear o mesmo de forma correta. Os rebocadores vetoriais normalmente são representados com modelos simplificados de forças externas atuantes em um navio a ser rebocado. A simplicidade de tais modelos gera uma grande perda de realismo durante uma simulação marítima dado que tanto as forças exercidas em um navio a ser rebocado quanto as posições de atuação dos rebocadores são imprecisas. Ainda, os tempos de resposta para a atuação dos rebocadores normalmente não é levado em conta nos modelos de rebocadores vetoriais presentes atualmente. O principal objetivo deste trabalho é prover uma abordagem inovadora para a modelagem da atuação de rebocadores vetoriais, de tal modo que a magnitude da sua força de reboque e seu posicionamento, tanto atuando no modo empurrar quanto no modo puxar, sejam fidedignos a realidade. O autor irá expandir o modelo de equilíbrio estático para predição de forças de atuação de rebocadores apresentado tanto em Brandner (1995) quanto em Artyszuk (2014), e irá introduzir técnicas de otimização de modo a obter a configuração precisa de atuação dos rebocadores tanto na manobra de modo direto quanto na manobra de modo indireto. As implementações propostas elevarão o nível de realidade de Simuladores Navais quando rebocadores vetoriais forem empregados.
6

Estabilidade de Carga no Problema de Carregamento de Contêineres

Oliveira, Liliane de Azevedo 22 February 2017 (has links)
Submitted by Erika Demachki (erikademachki@gmail.com) on 2017-06-21T21:21:46Z No. of bitstreams: 2 Dissertação - Liliane de Azevedo Oliveira - 2017.pdf: 1274368 bytes, checksum: 9b7a4aa781e0951c3f12045277a55582 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2017-06-29T18:27:23Z (GMT) No. of bitstreams: 2 Dissertação - Liliane de Azevedo Oliveira - 2017.pdf: 1274368 bytes, checksum: 9b7a4aa781e0951c3f12045277a55582 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-06-29T18:27:23Z (GMT). No. of bitstreams: 2 Dissertação - Liliane de Azevedo Oliveira - 2017.pdf: 1274368 bytes, checksum: 9b7a4aa781e0951c3f12045277a55582 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-22 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / In this work we applied an algorithm based on the resolution of integer linear models for the problem of packing boxes into a single container considering the cargo stability constraint. The problem consists of arranging items (boxes) of different sizes inside a large object (container) to maximize the occupied container volume while respecting the imposed constraints. Four methods are investigated and compared due to vertical cargo stability, in which three of these methods are proposed in this work and based on the equilibrium of rigid bodies, and the other one is based on the factor of support of boxes bottom faces. In the case of the factor of support, a set of constraints can be inserted totally in the integer formulation, while in the other methods cutting planes are inserted during optimization of the formulation by a branch-and-cut algorithm. Computational tests on instances from the literature show that the usage of a factor of support underestimates the value of the optimal solution. The computational tests showed that the use of the factor of support may underestimate the solution, but its use with integer linear programming models has the advantage that feasible solutions are stable, while the other developed methods only verify stability and thus they depend of the integer linear program to return feasible solutions more quickly. By the way, the methods for the cargo stability developed here also overcame the factor of support for tests involving different types of mesh to pack into the container. / Aplica-se um algoritmo baseado na resolução de modelos de programação linear inteira para o problema de carregamento de caixas dentro de um único contêiner considerando a restrição de estabilidade de carga. O problema em estudo consiste em arranjar itens (caixas) de diferentes tamanhos dentro de um objeto maior (contêiner), de maneira maximizar a ocupação do volume do contêiner enquanto respeita as restrições dadas. Quatro métodos são investigados e comparados quanto a estabilidade vertical do empacotamento, sendo que três deles são desenvolvidos neste trabalho e baseados em conceitos do equilíbrio de corpos rígidos, enquanto um deles é baseado no fator de suporte da base das caixas. No caso do fator de suporte, um conjunto de restrições pode ser inserido totalmente dentro da formulação inteira, enquanto nos demais métodos planos de corte são inseridos durante a resolução da formulação por um algoritmo branch-and-cut. Os testes computacionais mostraram que o uso do fator de suporte pode subestimar a solução, porém seu uso com modelos de programação linear inteira tem a vantagem das soluções viáveis poderem ser estáveis, enquanto os demais métodos desenvolvidos apenas verificam a estabilidade e, assim, dependem do programa linear inteiro retornar soluções viáveis mais rapidamente. Os métodos para a estabilidade de carga desenvolvidos neste trabalho mostraram-se superiores ao fator de suporte para testes envolvendo diferentes tipos de malhas para o empacotamento no contêiner.
7

La stratégie militaire des Cananéo-phéniciens d'après les sources archéologiques et historiques / The military strategy of Cananeo-Phoenician according to archaeological and historical sources

Jalbout, Ziad 26 November 2018 (has links)
La stratégie militaire des Cananéo-phéniciens à l'âge du Bronze constitue le sujet développé dans cette thèse. Celle-ci se base sur l'étude des fortifications, des armes, des textes historiques, des figurines armées et des représentations sur des bas-reliefs et sur des sceaux-cylindres. Les deux volets principaux de ce travail s'articulent donc autour des fortifications et des armes. L'étude des systèmes défensifs est menée à la lumière d'une approche scientifique inédite se basant sur la mécanique statique. Les fortifications répertoriées ont été découvertes au Levant-Nord, notamment à Byblos et à Ougarit, et dans des nombreux autres sites de la région. L'analyse de ces systèmes défensifs montre que les tours, les bastions, les remparts, les murs, les casemates et les fossés sont destinés à entraver la progression des machines de guerre et des soldats ; de même que les contreforts, les glacis, les noyaux et les murs de soutènement sont conçus pour assurer l'équilibre statique des fortifications. Le corpus d'armes cataloguées se compose de 1344 éléments provenant de Byblos et d'Ougarit principalement. Une partie de ces armes a été analysée à la Direction générale des antiquités de Beyrouth et une autre partie a été traitée suivant une approche informatique se basant sur la reconstitution virtuelle du Tell de Byblos. Suivant leur fonction, ces armes sont distribuées en armes à comte portée ; en armes à longue portée ; en armes défensives et finalement en machines de guerre. En conclusion, cette étude trace les grandes étapes de l'histoire militaire des Cananéo-phéniciens tout en montrant que la stratégie militaire adoptée par ce peuple était défensive. / The military strategy of the Cananeo-Phoenicians in the Bronze Age is the subject developed in this thesis. It is based on the study of fortifications, weapons, historical texts, armed figurines, and representations on reliefs, and cylinder seals. Hence, the two main components of this work are articulated around fortifications and weapons. The study of defensive systems is conducted in the light of an unprecedented scientific approach based on static mechanics. The listed fortifications have been discovered in North Levant, particularly in Byblos, Ugarit, and many other sites in the region. The analysis of these defensive systems shows that towers, bastions, ramparts, walls, casemates, and fosses are intended to hinder the progress of war machines and soldiers; in addition, the buttresses, glacis, cores, and retaining walls are designed to ensure the static equilibrium of those fortifications. The catalog of weapons consists of 1344 items discovered mainly in Byblos and Ugarit. Some of these weapons were analyzed at the General Directorate of Antiquities of Beirut while some others are treated using a computerized approach based on the virtual reconstruction of Byblos Tell. Depending on their function, these weapons are distributed on short-range weapons, long-range weapons, defensive weapons, and finally war machines. In conclusion, this study traces the stages of Cananeo-Phoenician military history and shows that the military strategy adopted by this people was defensive.
8

Automobilio svyravimai ekstremalaus stabdymo metu / Oscillations of the vehicle in emergency braking

Pečeliūnas, Robertas 24 February 2005 (has links)
The suspension of the motor vehicle is one of the most important elements of the flexible mounted and inflexible mounted masses of the vehicle bodywork, and most attention is paid to its exploration and improvement. Analysis of models of equivalent oscillation systems of motor vehicles testifies that the evaluation of motor vehicle oscillations and modelling of its motion modes is still very topical and requires further research. Suspension models of motor vehicles offered in publications regard only the influence of road irregularities, and the modernisation of these models is directed towards the improvement of passengers’ comfort. However not much research has been done on the influence of oscillations of flexible mounted and inflexible mounted masses of the bodyworks of vehicles in the process of braking; also there is not much investigation of the post-accident identification of the vehicle’s movement mode corresponding to the deformations of the suspension and the longitudinal pitch of the bodywork. Research of oscillations in the conditions of emergency braking is primarily important for the work in two practical directions: 1) improvement of calculation methods of motor vehicle’s response to external impact in the conditions of real operation; 2) further improvement of research methods on the road, and analysis of fait accompli road accidents related to oscillations in the emergency braking. Methodology defining the oscillations occurring in the braking may be applied... [to full text]
9

Automobilio svyravimai ekstremalaus stabdymo metu / Oscillations of the vehicle in emergency braking

Pečeliūnas, Robertas 25 February 2005 (has links)
The suspension of the motor vehicle is one of the most important elements of the flexible mounted and inflexible mounted masses of the vehicle bodywork, and most attention is paid to its exploration and improvement. Analysis of models of equivalent oscillation systems of motor vehicles testifies that the evaluation of motor vehicle oscillations and modelling of its motion modes is still very topical and requires further research. Suspension models of motor vehicles offered in publications regard only the influence of road irregularities, and the modernisation of these models is directed towards the improvement of passengers’ comfort. However not much research has been done on the influence of oscillations of flexible mounted and inflexible mounted masses of the bodyworks of vehicles in the process of braking; also there is not much investigation of the post-accident identification of the vehicle’s movement mode corresponding to the deformations of the suspension and the longitudinal pitch of the bodywork. Research of oscillations in the conditions of emergency braking is primarily important for the work in two practical directions: 1) improvement of calculation methods of motor vehicle’s response to external impact in the conditions of real operation; 2) further improvement of research methods on the road, and analysis of fait accompli road accidents related to oscillations in the emergency braking. Methodology defining the oscillations occurring in the braking may be applied... [to full text]

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