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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

Using Two-Dimensional Numerical Models to Analyze Hydraulic Effects of Constricted Flows through the Rigolets Pass between Lake Pontchartrain and Lake Borgne

Ischen, Marc 15 May 2009 (has links)
The objective of this study was to determine if numerical models commonly used for large scale applications could also be used to model flow through flood control structures in the Rigolets Pass between Lake Borgne and Lake Pontchartrain. For this purpose a small scale physical model was built. It showed that bi-stable flow can develop downstream of a constriction. Small changes in the distribution of the approaching flow significantly impacted flows downstream of the constriction. This behavior could not be properly reproduced by a small scale 2-dimensional RMA2 model of identical dimensions. A large scale RMA2 model of the Rigolets testing possible locations and geometries of flood control structures showed that this pass is very sensitive to variations in the cross sectional flow area. Even minor reductions can significantly increase headlosses and velocities. To reduce negative impacts a flood control structure should be built in a wide and shallow area of the pass.
2

Proposição de modelo de desempenho econômico-financeiro baseado em governança para cooperativas agrícolas /

January 2019 (has links)
Resumo: O objetivo do presente trabalho é: Propor um modelo de desempenho econômico-financeiro com base em princípios e práticas da Governança Corporativa aplicado às cooperativas agrícolas. Trata-se de uma pesquisa com abordagem quantitativa, a partir de um estudo empírico com finalidade aplicada, pois tem como propósito desenvolver um modelo que possa ser utilizado por cooperativas agrícolas. Os dados da pesquisa foram tomados de uma amostra com 48 cooperativas agrícolas estabelecidas no Brasil, a partir de um questionário. Os procedimentos de pesquisa concentraram na análise descritiva dos resultados empírico e no emprego da análise fatorial e análise discriminante. Os resultados obtidos a partir das técnicas estatísticas utilizadas agruparam as variáveis propostas no questionário gerando fatores que explicaram a governança e o desempenho. As variáveis discriminantes foram exploradas para discriminar as cooperativas com as melhores práticas de governança cooperativa apontadas no questionário. Assim, ficou constatado que a governança exerce influência nos resultados econômicos das cooperativas. O estudo realizado possibilita aos gestores e interessados uma visão mais ampla da cooperativa, que precisa contar com a integração de todos os agentes, de modo que se ajudem mutuamente no desenvolvimento das suas atividades para o bem da cooperativa. A busca por alternativas para melhorar o desempenho e apresentar melhores resultados aos cooperados está intimamente relacionada ao acompanham... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this paper is: To propose a model of economic and financial performance based on the principles and practices of Corporate Governance applied to agricultural cooperatives. This is a research with a quantitative approach, based on an empirical study with an applied purpose, as its purpose is to develop a model that can be used by agricultural cooperatives. The survey data were taken from a sample of 48 agricultural cooperatives established in Brazil from a questionnaire. The research procedures focused on the descriptive analysis of the empirical results and the use of factor analysis and discriminant analysis. The results obtained from the statistical techniques used grouped the variables proposed in the questionnaire generating factors that explained governance and performance. Discriminant variables were explored to discriminate cooperatives with the best practices of cooperative governance indicated in the questionnaire. Thus, it was found that governance influences the economic results of cooperatives. The study provides managers and stakeholders with a broader view of the cooperative, which needs to have the integration of all agents, so that they help each other in the development of their activities for the good of the cooperative. The search for alternatives to improve the performance and to present better results to the members is closely related to the monitoring of the cooperative's financial health, it is important to know the cooperative's level ... (Complete abstract click electronic access below) / Mestre
3

The Effects of Erosion-control Structures and Gully Erosion on Groundwater Dynamics Along the Kromrivier, Eastern Cape, South Africa

de Haan, Vincent January 2016 (has links)
The Palmiet wetlands located along the Kromrivier in the Eastern Cape province of South Africa have experienced severe degradation through gully erosion during the past decennia which has been threatening the water quality and water security of large towns in the Nelson Mandela Metropolitan hub. Water scarcity is a growing problem in this region as a result of land degradation and growing erratic rainfall patterns. The main causes of wetland degradation are argued to be land use and land cover change. With the aim of protecting the wetlands along the Kromrivier a total of eleven large gabion and concrete erosion-control structures were constructed between the 2002 and 2013 by the government initiate Working for Wetlands. This study aims to map the groundwater table in order to derive how erosion-control structures and gully erosion affect groundwater dynamics along the Kromrivier. This was achieved by several steps. Firstly, water table elevations were measured along several transects by installing a series of piezometers which allowed do investigate how the structures affected the water table. This also allowed for a comparison in groundwater dynamics between eroded and non-eroded reaches so that effects of gully erosion could be identified and potential causes discussed. Secondly, the analysis of aerial images allowed for the development of the aerial extent of the Palmiet wetland and gullies to be seen over a ten year period and longitudinal profiles provided specific characteristics of the wetland and gullies. Lastly, particle size distribution and organic matter content were analyzed as groundwater flow and gully erosion can vary greatly depending on soil characteristics. The hydraulic gradient was highest in proximity to the structures as a result of the created potential induced by the drop in surface water elevation. The radius of influence to where the structures were affected the water table was estimated to be approximately 40 m from the channel. Further away from the channel, the gradual slope of the water table indicated that the porous gabion side walls of the structures did not affect the water table. The groundwater flow is determined by Darcy's Law and the relatively flat water table along the non-eroded reaches of site A displayed local drainage points, thereby indicating variations in the local flow direction. In May the water table along the non-eroded reaches was sloping away from the channel resulting in an area of groundwater discharge with respect to the channel. Not only was the water table generally higher during August, the regime had also changed, indicating a potentially large seasonal variability. Along the eroded reaches downstream from the structures the water table was above the gully bottom during both months resulting in an area of groundwater recharge with respect to the channel. Also here the regime had changed from an approximately constant hydraulic gradient sloping towards the channel during May to a water table with a divide in flow direction. Since their implementation in 2003, the structures have been effective with respect to preventing the headcut in the main channel from migrating further upstream. However, the gullies downstream of the structures had significantly increased in width between 2003 and 2013 and the Palmiet wetland had also slightly decreased in size during the same period. However, it was unclear whether this decrease was part of the longer term ongoing trend or part of a shorter term cycle and/or seasonal fluctuation. For a gully bank to collapse, the shear strength of the slip surface needs to be exceeded and this often occurs because of an increase in pore water pressurewhich causes a reduction in shear strength. A large gully height of up to 4 m with nearly vertical slopes, a water table above the gully bottom and an increase in moisture content between May and August indicated that it is not unlikely that a high pore water pressure. played a significant role in the slumping of the gully walls. The two structures together were responsible for an surface water elevation difference of 7.76 m. Through damming this resulted in an elevated water table in the upstream Palmiet wetland, thereby increasing the saturation and promoting diffuse flow across the wetland. However, the structures also trap most of the sediment in upstream direction which appears to have resulted in the de-stabilization of the downstream streambed at site A as these eroded reaches now receive a significantly lower sediment load. By increasing the retention volume in the wetland, the structures also facilitated in ensuring flood retention as the wetland could now hold more water during high flows, thereby cutting off the peak flow. As gully erosion is known to occur during periods of high flow it is not unreasonable to argue that slumping of the gully walls would have been more severe without the structures in place. In this sense the structures increase the water quality and decrease the flux of sediment where the latter leads to a decrease in the sedimentation rate of the downstream Churchill Dam. Consequently, this contributes to securing the fresh water supply to towns in the Nelson Mandela Metropolitan hub. The discovery of Palmiet rests up to 2.6 m below the surface indicated that cycles of gully erosion followed by the re-establishment of Palmiet have been occurring in this valley for thousands of years. However, it seemed that land use and land cover changes had accelerated gully erosion during the past decades resulting in a loss of Palmiet wetland at a rate which was beyond 'natural'. Even though the structures could be seen as disruptions of long term natural cycles, they are in favor of the well-being of mankind as they protect the wetlands to a certain extent. The main results of this study provided a basic understanding of how the water table behaves in response to the structures and along eroded and non-eroded reaches of the Kromrivier. Furthermore, this study discussed the larger scale affects of the structures and showed how the gullies and the aerial extent of the Palmiet wetland have evolved since the implementation of the structures in 2003. In order to manage these Palmiet wetlands more effectively in the future, it is highly important that groundwater dynamics, gully erosion and the size and health of the wetland are annually monitored in order to get a more accurate idea of how effective these structures are. This new obtained knowledge could also assist in managing other peat lands in South Africa more effectively.
4

Assessing Potential Spawning Habitat and Barriers to Migratory Walleye on The Sandusky River, Ohio

Myers, Madison R. January 2021 (has links)
No description available.
5

Managing Lithographic Variations in Design, Reliability, and Test Using Statistical Techniques

Sreedhar, Aswin 01 February 2011 (has links)
Much of today's high performance computing engines and hand-held mobile devices are products of aggressive CMOS scaling. Technology scaling in semiconductor industry is mainly driven by corresponding improvements in optical lithography technology. Photolithography, the art used to create patterns on the wafer is at the heart of the semiconductor manufacturing process. Lately, improvements in optical technology have been difficult and slow. The transition to deep ultra-violet (DUV) light source (193nm) required changes in lens materials, mask blanks, light source and photoresist. It took more than ten years to develop a stable chemically amplified resist (CAR) for DUV. Consequently, as the industry moves towards manufacturing end-of-the-roadmap CMOS devices, lithography is still based on 193nm light source to print critical dimensions of 45nm, 32nm and likely 22nm. Sub-wavelength lithography creates a number of printability issues. The printed patterns are highly sensitive to topographic changes due to metal planarization, overlay errors, focus and dose variations, random particle defects to name a few. Design for Manufacturability methodologies came into being to help analyze and mitigate manufacturing impacts on the design. Although techniques such as Resolution Enhancement Techniques (RET) which involve optical proximity correction (OPC), phase shift masking (PSM), off-axis illumination (OAI) have been used to greatly improve the printability and better the manufacturing process window, they cannot perfectly compensate for these lithographic deficiencies. DFM methods were primarily devised to predict and correct systematic patterning problems that arise during manufacturing. Apart from systematic errors, random manufacturing variations may occur during photolithography. This is where a statistical approach to modeling of error behavior and its impact on different design parameters may prove to be effective. By incorporating statistical analysis to parameter variation, an effective, non-conservative design can be obtained. IC manufacturing yield is the foremost measure that determines the profitability of a given semiconductor manufacturing process. Thus early prediction of yield detractors is an important step in the design process. Such predictions are based on models, which in turn are rooted in manufacturing process. Success of yield prediction is based on quality of models. The models must capture physical phenomena and yet be efficient for computation. In this work, we present a lithography-based yield model that is computationally practical for use in the design process. The work also provides a methodology to perform statistical lithography rules check to identify hot spots in the design that can contribute to yield loss. Yield recovery methods aimed at minimally modifying the design ultimately produce more printable masks. Apart from IC manufacturing yield, ICs today are vulnerable to various reliability failures including electromigration (EM), negative bias temperature instability (NBTI), hot carrier injection (HCI) and electro-static discharge (ESD). Though such reliability issues have been examined since the beginning of CMOS, manufacturability impacts have created a renewed interest in analyzing them. In this dissertation, we introduce the concept of Design for reliable manufacturability (DFRM) to consider the effect of linewidth changes, gate oxide thickness variations and other manufacturing artifacts. A novel Litho-aware EM calibration and analysis has bee shown in this work. Results indicate that there is a significant difference in EM estimation when litho-predicted layouts are considered during analysis. DFM has always looked at linewidth and material thickness variation as detractors to the design. However, such variations are inevitable. In this work we also consider modeling sensitivity to variations to improve test pattern quality. Test structures sprinkled all over the wafer encounter varying process fluctuations. This can be harnessed to predict the current lithographic process corner which will later be used to choose the test pattern set that results in maximum fault coverage. In summary, the objective of this dissertation is to consider the impact of sub-wavelength lithography on printability and the overall impact on circuit reliability and manufacturing test development.
6

Desenvolvimento de um rastreador solar do tipo polar com ajuste do ?ngulo de inclina??o

Lira, Jos? R?mulo Vieira 23 January 2014 (has links)
Made available in DSpace on 2014-12-17T14:56:16Z (GMT). No. of bitstreams: 1 JoseRVL_DISSERT.pdf: 1074051 bytes, checksum: 14c63dffcde0a8f8267956ed973bedb7 (MD5) Previous issue date: 2014-01-23 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The use of solar energy for electricity generation has shown a growing interest in recent years. Generally, the conversion of solar energy into electricity is made by PV modules installed on fixed structures, with slope determined by the latitude of the installation site. In this sense, the use of mobile structures with solar tracking, has enabled increased production of the generated energy. However, the performance of these structures depends on the type of tracker and the position control used. In this work, it is proposed position control a strategy applied for a solar tracker, which will be installed in Laboratory of Power Electronics and Renewable Energy (LEPER), located in the Federal University of Rio Grande do Norte (UFRN). The tracker system is of polar type with daily positioning east-west and tilt angle manual adjustment in the seasonal periods, from north to south / O aproveitamento da energia solar para gera??o de energia el?trica tem apresentado um crescente interesse nos ?ltimos anos. Geralmente nestes sistemas, a convers?o de energia solar em el?trica ? realizada por m?dulos fotovoltaicos, instalados em estruturas fixas, com inclina??o determinada em fun??o da latitude do local de instala??o. Neste sentido, o uso de estruturas m?veis, com rastreamento solar, tem possibilitado o incremento da produ??o da energia gerada. Por?m, o desempenho dessas estruturas depende do tipo de rastreador instalado e do tipo de controle de posi??o utilizado. Nesta disserta??o, ? empregada uma estrat?gia de controle de posi??o aplicada a um rastreador solar, que ser? instalado no Laborat?rio de Eletr?nica de Pot?ncia e Energias Renov?veis (LEPER), localizado na Universidade Federal do Rio Grande do Norte (UFRN). O rastreador ser? do tipo polar, com rastreamento di?rio no sentido leste-oeste e ajuste do ?ngulo de inclina??o manual nos per?odos sazonais, no sentido norte-sul
7

Concentração e dispersão do poder político nas organizações coletivas finalísticas. Regime jurídico da companhia aberta integrante do novo mercado da bolsa de valores: o papel decisivo desempenhado pelos instrumentos jurídicos de dissociação entre representatividade política e participação economica de acionistas no âmbito da companhia / Concentration and dispersion of political power in organization: legal regimen of disperted ownership companies in the Brazilian novo market: the separation of ownership and cash-flow rights.

Azevedo, Luís André Negrelli de Moura 16 April 2015 (has links)
Ao redor do mundo, a maioria das companhias listadas de grande porte tem acionista controlador, à exceção dos EUA e do RU, em que o comando da atividade empresarial é exercido, de fato, pelos administradores. A conformação de controle dominante em cada país resulta de uma série de fatores, muitos deles de ordem jurídica, os quais levam ao surgimento e permanência de uma dessas variantes, ao mesmo tempo em que parecem inibir o desenvolvimento da estrutura alternativa. A gradativa convergência global dos padrões de propriedade acionária a um denominador comum, aparentemente em curso - dos extremos da dispersão e concentração absolutas para o cenário intermediário dos blocos de participação minoritária relevante detidos por investidores institucionais não tem sido acompanhada de transformações significativas nas estruturas de poder de controle interno dominantes em cada país, as quais, em essência, continuam as mesmas. Isso significa que os fatores (jurídicos, especialmente) que levam à predominância de tais estruturas continuam em atuação, não obstante modificações havidas no grau de dispersão do capital com direito a voto de companhias listadas. Este trabalho visa apresentar um conjunto mais específico de fatores jurídicos que, ao mesmo tempo e de modo decisivo, favorecem a proliferação de uma dentre as duas estruturas de controle consideradas (controle acionário ou gerencial) e inibem o desenvolvimento de outra. Trata-se dos instrumentos jurídicos de dissociação entre representatividade política e participação econômica de acionistas, os quais exercem papel central na conformação do regime jurídico das companhias abertas com elevada dispersão do capital votante, integrantes do Novo Mercado da BVSP. / Most of the large listed companies outside USA and UK have a controlling shareholder. The dominant control structure in each country is the result of multiple determinants, many of them arising from the legal system. The gradual convergence of ownership patterns around the world from the extremes of the total concentration and separation of ownership and control to the intermediate scenario of significant blockholdings held by institutional investors - has not been accompanied by a relevant shift in the control structures in listed companies of most of the countries, specially those in the Brazilian Novo Mercado. This Doctorate Thesis presents a specific subset of legal factors contributing for that outcome: the legal instruments separating voting rights from cashflow rights.
8

Neural preprocessing and control of reactive walking machines : towards versatile artificial perception-action systems /

Manoonpong, Poramate. January 2007 (has links)
A aussi paru sous forme de thèse: Siegen, Univ., 2006.
9

Concentração e dispersão do poder político nas organizações coletivas finalísticas. Regime jurídico da companhia aberta integrante do novo mercado da bolsa de valores: o papel decisivo desempenhado pelos instrumentos jurídicos de dissociação entre representatividade política e participação economica de acionistas no âmbito da companhia / Concentration and dispersion of political power in organization: legal regimen of disperted ownership companies in the Brazilian novo market: the separation of ownership and cash-flow rights.

Luís André Negrelli de Moura Azevedo 16 April 2015 (has links)
Ao redor do mundo, a maioria das companhias listadas de grande porte tem acionista controlador, à exceção dos EUA e do RU, em que o comando da atividade empresarial é exercido, de fato, pelos administradores. A conformação de controle dominante em cada país resulta de uma série de fatores, muitos deles de ordem jurídica, os quais levam ao surgimento e permanência de uma dessas variantes, ao mesmo tempo em que parecem inibir o desenvolvimento da estrutura alternativa. A gradativa convergência global dos padrões de propriedade acionária a um denominador comum, aparentemente em curso - dos extremos da dispersão e concentração absolutas para o cenário intermediário dos blocos de participação minoritária relevante detidos por investidores institucionais não tem sido acompanhada de transformações significativas nas estruturas de poder de controle interno dominantes em cada país, as quais, em essência, continuam as mesmas. Isso significa que os fatores (jurídicos, especialmente) que levam à predominância de tais estruturas continuam em atuação, não obstante modificações havidas no grau de dispersão do capital com direito a voto de companhias listadas. Este trabalho visa apresentar um conjunto mais específico de fatores jurídicos que, ao mesmo tempo e de modo decisivo, favorecem a proliferação de uma dentre as duas estruturas de controle consideradas (controle acionário ou gerencial) e inibem o desenvolvimento de outra. Trata-se dos instrumentos jurídicos de dissociação entre representatividade política e participação econômica de acionistas, os quais exercem papel central na conformação do regime jurídico das companhias abertas com elevada dispersão do capital votante, integrantes do Novo Mercado da BVSP. / Most of the large listed companies outside USA and UK have a controlling shareholder. The dominant control structure in each country is the result of multiple determinants, many of them arising from the legal system. The gradual convergence of ownership patterns around the world from the extremes of the total concentration and separation of ownership and control to the intermediate scenario of significant blockholdings held by institutional investors - has not been accompanied by a relevant shift in the control structures in listed companies of most of the countries, specially those in the Brazilian Novo Mercado. This Doctorate Thesis presents a specific subset of legal factors contributing for that outcome: the legal instruments separating voting rights from cashflow rights.
10

The effects of state ownership in the internationalization of emerging multinationals

Arreola, Maria Fernanda 28 July 2014 (has links)
Submitted by Maria Fernanda Arreola Croda (fernanda.arreola@gmail.com) on 2014-08-18T13:40:54Z No. of bitstreams: 1 Tese Maria Fernanda Arreola.pdf: 1365605 bytes, checksum: bc44261ba0ee9e9106bd00f16c83014f (MD5) / Approved for entry into archive by PAMELA BELTRAN TONSA (pamela.tonsa@fgv.br) on 2014-08-18T13:42:11Z (GMT) No. of bitstreams: 1 Tese Maria Fernanda Arreola.pdf: 1365605 bytes, checksum: bc44261ba0ee9e9106bd00f16c83014f (MD5) / Made available in DSpace on 2014-08-18T13:48:38Z (GMT). No. of bitstreams: 1 Tese Maria Fernanda Arreola.pdf: 1365605 bytes, checksum: bc44261ba0ee9e9106bd00f16c83014f (MD5) Previous issue date: 2014-07-28 / This thesis is a collection of three different research projects analyzing the effect of state ownership in the internationalization of Emerging Multinationals (EMNEs). The participation of the state as shareholder is a phenomenon that can bring new light into the governance, management and strategic impact of having states participate as owners in different levels. These studies will allow us to explore, from different perspectives, the extent to which states, while owners, can impact the EMNE. The studies thee contained go from exploring the selection mechanisms for a firm to become the target of state ownership to its effect on the internationalization pace, passing through the revision of the mechanisms available for the state to gain control and access to a firm’s decision making, through changes to its corporate governance. / Esta tese é um compendio de três trabalhos de pesquisa que visam analisar o efeito da participação do estado na estrutura de propriedade das Multinacionais de Países Emergentes (EMNEs). A participação do estado como acionista é um fenómeno que pode trazer novas contribuições no âmbito da governança corporativa, administração da empresa e a tomada de decisões estratégicas. Os estudos aqui inclusos permitem identificar, a partir de momentos, diferentes, até que ponto o estado, na posição de proprietário da EMNE, pode impactar a mesma. Os trabalhos vão desde os mecanismos de escolha de firmas nas quais investir ate o impacto no ritmo de internacionalização das empresas, explicando também os mecanismos que o estado usa para ganhar aceso à tomada de decisões por meio de mudanças na governança corporativa

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