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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

Peak Population: Timing and Influences of Peak Energy on the World and the United States

Warner, Kevin 1987- 14 March 2013 (has links)
Peak energy is the notion that the world’s total production of usable energy will reach a maximum value and then begin an inexorable decline. Ninety-two percent of the world’s energy is currently derived from the non-renewable sources (oil, coal, natural gas and nuclear). As each of these non-renewable sources individually peaks in production, we can see total energy production peak. The human population is tightly correlated with global energy production, as agriculture and material possessions are energy intensive. It follows that peak energy should have a significant effect on world population. Using a set of mathematical models, including M King Hubbert’s oil peak mathematics, we prepared three models. The first approached the peak energy and population problem from the point of view of a “black-box” homogeneous world. The second model divides the world into ten major regions to study the global heterogeneity of the peak energy and population question. Both of these models include various scenarios for how the world population will develop based on available energy and per capita consumption of that energy. The third model examines energy and climate change within the forty-eight contiguous American states in order to identify some of the “best” and some of the “worst” states in which to live in the year 2050. The black box model indicates that peak energy will occur in 2026 at a maximum production of 104.1 billion barrels of oil equivalent (BBOE). Total energy production in 2011 was 92.78 BBOE. Three scenarios of different energy consumption rates suggest a peak world population occurring between 2026 and 2036, at 7.6-8.3 billion. The regional model indicates that even as each region protects its own energy resources, most of the world will reach peak energy by 2030, and world populations peak between 7.5 and 9 billion. A certain robustness in our conclusion is warranted as similar numbers were obtained via two separate approaches. The third model used several different parameters in order to ascertain that, in general, states that are projected to slow towards flat-line population growth and to become milder due to climate change such as Rhode Island, New York and Ohio are far more suitable with regard to an energy limited world than states that are projected to grow in population as well as become less mild due to climate change such as Texas, Arizona and Nevada. Each of these models in its own way foreshadows necessary changes that the world will experience as the 21st century progresses. The economies of the world have been, and continue to be, built on energy. When energy production is unable to continue growing it must follow that economies will be unable to grow. As the world approaches and passes peak energy, the standard of living in the less developed areas of the world cannot improve without sacrifices being made in the developed world.
2

Statistically Evaluating Water Consumption Historically and Across Multiple Users in Virginia

DiCarlo, Morgan 11 June 2018 (has links)
This study explores key aspects of water usage in Virginia via a broad-scale analysis of multiple water users through thirty years of time-series records from the Virginia Water Use Data System. A full spectrum of users is considered, including water used for energy, industrial, agricultural and municipal applications. The extent of the relationship between the volume of water used and drivers like economic and climatic conditions are not well defined in humid environments like Virginia. Mann-Kendall testing is applied to identify water use trends through time both statewide and at the county level. A panel regression is employed to identify relationships between water use and explanatory variables of climatic and economic conditions, both spatially and temporally. Key trends include that industrial and energy sector water withdrawals per facility are significantly decreasing over time. Water used for agricultural applications was found to increase on warmer than average years and decrease on wetter than average years, indicating the panel regression methodology successfully demonstrated and quantified intuitive trends. Interestingly, municipal and industrial water usage had a statistically significant relationship with the Gini coefficient, a measure of inequality in rainfall distribution, indicating intraseasonal variability may play an important role in water use trends that is not apparent using seasonal averages alone. Overall, this work contributes to the understanding of water use trends at the state level for Virginia, and better characterizes long-term trends and short-term variability in water withdrawal. / MS
3

Minimizing Energy Consumption in a Water Distribution System: A Systems Modeling Approach

Johnston, John 2011 May 1900 (has links)
In a water distribution system from groundwater supply, the bulk of energy consumption is expended at pump stations. These pumps pressurize the water and transport it from the aquifer to the distribution system and to elevated storage tanks. Each pump in the system has a range of possible operating conditions with varying flow rates, hydraulic head imparted, and hydraulic efficiencies. In this research, the water distribution system of a mid-sized city in a subtropical climate is modeled and optimized in order to minimize the energy usage of its fourteen pumps. A simplified model of the pipes, pumps, and storage tanks is designed using freely-available EPANET hydraulic modeling software. Physical and operational parameters of this model are calibrated against five weeks of observed data using a genetic algorithm to predict storage tank volume given a forecasted system demand. Uncertainty analysis on the calibrated parameters is performed to assess model sensitivity. Finally, the pumping schedule for the system's fourteen pumps is optimized using a genetic algorithm in order to minimize total energy use across a 24-hour period.
4

Fuzzy Nonprehensile Manipulation Control of a Two-Rigid-Link Object by Two Cooperative Arms

Hosoe, Shigeyuki, Hayakawa, Yoshikazu, Zyada, Zakarya 09 1900 (has links)
the 18th World Congress The International Federation of Automatic Control, Milano (Italy), August 28 - September 2, 2011
5

Understanding the centralized-decentralized electrification paradigm

Levin, Todd 27 August 2014 (has links)
Two methodologies are presented for analyzing the choice between centralized and decentralized energy infrastructures from a least-cost perspective. The first of these develops a novel minimum spanning tree network algorithm to approximate the shortest-length network that connects a given fraction of total system population. This algorithm is used to identify high priority locations for decentralized electrification in 150 countries. The second methodology utilizes a mixed-integer programming framework to determine the least-cost combination of centralized and decentralized electricity infrastructure that is capable of serving demand throughout a given system. This methodology is demonstrated through a case study of Rwanda. The centralized-decentralized electrification paradigm is also approached from an energy security perspective, incorporating stochastic events and probabilistic parameters into a simulation model that is used to compare different development paths. The impact of explicitly modeling stochastic events as opposed to utilizing a conventional formulation is also considered Finally, a subsidy-free lighting cost curve is developed and a model is presented to compare the costs and benefits of three different financial mechanisms that can be employed to make capital intensive energy systems more accessible to rural populations. The optimal contract is determined on the basis of utility-maximization for a range of costs to the providing agency and a comprehensive single and multi-factor sensitivity analysis is performed.
6

Applying systems modeling and case study methodologies to develop building information modeling for masonry construction

Lee, Bryan 08 June 2015 (has links)
Building Information Modeling, or BIM, is a digital representation of physical and functional characteristics of a facility that serves as a shared resource for information for decision-making throughout the project lifecycle (National Institute of Building Sciences, 2007). The masonry construction industry currently suffers from the lack of BIM integration. Where other industries and trades have increased productivity by implementing standards for software-enhanced workflows, masonry construction has failed to adopt information tools and processes. New information technology and process modeling tools have grown in popularity and their use is helping to understand and improve construction processes. The Systems Modeling Language, or SysML, is one of the process modeling tools we can use to model and analyze the various processes and workflows. In this research, a case study methodology was applied to analyze the masonry construction industry to understand the current state of masonry construction processes and workflows. This thesis reviews these concepts and the applied case studies which are necessary to move forward with the implementation of BIM for masonry.
7

Modeling of jet vane heat-transfer characteristics and simulation of thermal response

Hatzenbuehler, Mark A. 06 1900 (has links)
Approved for public release; distribution is unlimited / The development of a dynamic computational model capable of predicting, with the requisite design certainty, the transient thermal response of jet vane thrust control systems has been undertaken. The modeling and simulation procedures utilized are based on the concept that the thermal processes associated with jet vane operation can be put into a transfer function form commonly found in the discipline of automatic controls. Well established system identification methods are employed to formulate and verify the relationships between the various gains and frequencies of the transfer function model and experimental data provided by Naval Weapons Center, China Lake. / http://archive.org/details/modelingofjetvan00hatz / Lieutenant, United States Navy
8

Sensibilidade ambiental ao óleo na bacia do Ribeirão Anhumas, Campinas-SP : proposta metodológica para análise conjunta de ambientes terrestres e fluviais /

Camargo, Danilo Mangaba de January 2019 (has links)
Orientador: Rosemarie Rohn Davies / Resumo: Dentre os diversos tipos de acidentes ambientais, aqueles vinculados ao derramamento de óleo têm sido recorrentes em diversos ambientes do globo e dadas as suas consequências, são alvos de destaque pela comunidade científica mundial. A Lei Federal 9.966, de 22 de abril de 2000 regulamenta as ações de transporte e armazenamento de petróleo no território brasileiro. De acordo com a referida lei, cabe ao órgão federal responsável pelo meio ambiente, a consolidação dos planos de contingência – local e regional, instituindo o Plano Nacional de Contingência. Nesse sentido, estão inseridas as cartas de sensibilidade a derrames de óleo (Cartas SAO), produtos cartográficos essenciais, constituídas como relevante fonte de informação na elaboração de planos de contingencia e na avaliação de danos e impactos provenientes desse tipo de ocorrência. A presente pesquisa apresenta a proposição de uma metodologia de análise multicriterial para avaliação da sensibilidade ambiental ao óleo nas áreas continentais, tendo a bacia hidrográfica como unidade de análise. A Bacia do Ribeirão das Anhumas, localizada entre os municípios de Campinas-SP e Paulínia-SP foi selecionada para o estudo de caso. De acordo com as características da região e após o levantamento de dados bibliográficos, foram levantados dez critérios de mapeamento, os quais foram ponderados e classificados em níveis de sensibilidade. Após a ponderação dos critérios, os mapas descritores de cada um deles foram integrados em um softwar... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Among the various types of environmental accidents, those linked to oil spills have been recurrent in several environments around the globe and given their consequences, they are highlighted by the world scientific community. The federal Law 9.966, of the April 22, 2000 regulates the transportation and storage of oil in the Brazilian territory. According to this law, it is the responsibility of the federal agency responsible for the environment to consolidate contingency plans - local and regional, establishing the National Contingency Plan. In this sense, the Oil Spill Sensitivity Map (SAO MAP), essential cartographic products, are included as a relevant source of information in the preparation of contingency plans and in the evaluation of damages and impacts arising from this type of occurrence. This work presents the proposal of a methodology based on multicriteria analysis to evaluate the environmental sensitivity to the oil in the continental areas, having the watershed as unit of analysis. The Ribeirão das Anhumas Watershed, located between the municipalities of Campinas-SP and Paulínia-SP was selected for the case study. According to the characteristics of the region and after the collection of bibliographical data, ten mapping criteria were collected, which were weighted and classified in sensitivity levels. After weighting the criteria, the descriptive maps of each of them were integrated in a geoprocessing software, from the equation characteristic of each model. Th... (Complete abstract click electronic access below) / Mestre
9

Modelagem e análise de requisitos de sistemas automatizados usando UML e Redes de Petri. / Modeling and analysis of requirements of automated systems using UML and Petri nets.

Salmon, Arianna Zoila Olivera 18 April 2017 (has links)
A fase inicial de projeto de sistemas, baseada na elicitação, modelagem e análise dos requisitos é considerada a mais complexa e a mais estratégica para obtenção de bons resultados. Por conseguinte, erros precisam ser detectados durante esta fase inicial, antes de começar a implementação, evitando assim o desperdício de tempo e recursos. Este trabalho propõe um método formal de modelagem, análise e verificação de requisitos, partindo de uma representação semi-formal de requisitos em UML, e utilizando o formalismo das Redes de Petri para proceder à modelagem, análise e verificação. Propriedades das redes de Petri, tais como invariantes, são usadas para analisar os requisitos, permitindo uma validação antecipada dos requisitos no processo de design. O objetivo deste trabalho é estender a aplicação das redes de Petri como representação formal para a modelagem e análise de requisitos, endereçando assim a fase anterior às especificações. Pressupõe-se a existência de uma disciplina de projeto baseada em modelos (model driven) que abrange a fase inicial do projeto e se propaga para a modelagem e verificação de soluções. Assim, a abordagem proposta nesta tese se encaixa plenamente em um processo orientado a modelos que use a mesma linguagem: as redes de Petri. / The first stage of system design, which includes elicitation, modeling, and analysis of requirements is considered at the same time, very complex and very strategic to achieve proper results.Therefore it is important to detect mistakes both, conceptual and in requirements, before implementation begins, avoiding the waste of time and resources. This work proposes a formal method for modeling, analysis and verification of requirements, starting with a semi-formal representation of requirements in UML. Petri net and its properties such as invariants are used to analyze requirements, thereby allowing that requirements can be validated earlier. The main objective of this work is to extend the application of Petri Nets, as a formal representation, to requirements phase, addressing specification building. It is assumed that there is a model driven design approach that encompass the initial (requirements) phase and goes through the modeling and verification of solutions. Therefore the approach proposed in this work fits a model driven general approach which could use the same formal language: Petri Nets.
10

Modelagem e controle de uma classe de sistemas multi-corpos móveis. / Modeling and control of a class of mobile multi-body systems.

Souza, Eric Conrado de 22 April 2008 (has links)
No que segue, propõe-se uma classe de sistemas robóticos multi-corpos, cujos corpos componentes estão fisicamente acoplados através de juntas rotativas ativas. Os sistemas da classe considerada possuem mobilidade irrestrita no espaço plano uma vez que propulsores distribuídos ao longo dos corpos do sistema. A modelagem dinâmica destes sistemas é apresentada sob as abordagens Hamiltoniana e Lagrangiana da mecânica analítica. A descrição destes métodos de modelagem, assim como os modelos por eles obtidos, é realizada com ênfase na interpretação geométrica da matemática envolvida. Alguns exemplos de parametrizações do espaço de fase do sistema são discutidos e exemplos de modelagem em função destas parametrizações são obtidos. Ademais, alguns critérios de análise de controlabilidade não-linear são revisados e aplicados aos modelos do sistema com a estrutura de entradas considerada. Alguns casos de estabilização da classe de sistemas são também discutidos. Resultados de simulação de estabilização são obtidos para sistemas através de estudos de casos. Sistemas completamente controlados no espaço de estados podem ser linearizados através de uma técnica de linearização por realimentação e estabilizados com uma realimentação de estados. Para os sistemas cuja controlabilidade é deficiente, propõe-se a modificação de um método de controle de sistemas sub-atuados e uma lei de controle por realimentação é obtida pela teoria de estabilidade de Lyapunov. A classe de sistemas aqui discutida possui grande potencial de aplicação nos ambientes espacial e submarino. / In the following, a class of multi-body robotic systems is proposed in which its system component bodies are physically coupled by active rotating joints. The systems belonging to the proposed class have unrestricted mobility on the plane since thrusters are distributed along the system. System dynamical modeling is obtained through the analytic mechanical Hamiltonian and Lagrangian methods. The presentation of these methods, as well as the dynamical models obtained by them, is realized with an emphasis in the geometrical interpretation of the corresponding mathematics. A few different system phase space parameterizations approaches are discussed and modeling examples are presented under these parameterizations. Additionally, some nonlinear controllability analysis criteria are reviewed and applied to system dynamical models composed by the input structure mentioned above. A few stabilization case studies for the class of systems are also discussed and simulation results are presented. Totally controlled systems in the phase space can be linearized by feedback linearization techniques and stabilized through a state feedback. For partially controllable systems a modification of a stabilization method for under-actuated systems is proposed which renders feedback control via Lypunov stability theory. The class of systems discussed has great potential for space and underwater applications.

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