Dissertations / Theses on the topic 'Em modelling'
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Jussila, T. (Tommi). "Modelling cancer: recapitulation of tumor growth in experimental systems in vivo and in vitro." Doctoral thesis, University of Oulu, 2000. http://urn.fi/urn:isbn:9514256433.
Full textBórtoli, Mario Eduardo de. "Efeito do entorno urbano sobre as ações do vento em edifícios." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2005. http://hdl.handle.net/10183/7844.
Full textIn this research work a methodology to determine loads on tall structures located in urban centres is proposed. The proposal is based in wind tunnel tests and considers a random distribution of the surface environment. As this study deals with the determination of wind loads on structures located in urban centres, firstly the background wind velocity field, characterized by a suburban terrain, which is defined by the Brazilian code of practice NBR/6123 as a terrain of Category IV, had to be reproduced. Thereafter, the near environment of the model under study was added. In order to take into account the variations of loads caused by the random environment, the structures that shape it were dimensioned using the Monte Carlo technique. A procedure to reproduce the surface neighbouring in central areas of large cities considering the random nature of both size and distribution of buildings is presented. This procedure allows simulating either random fields or processes, in this case the neighbouring, which is defined as a three-dimensional random field, in terms of both its probability density and its spectral density. The structure of the lower part of the urban boundary layer was studied by means of measurements at different heights of both fluctuating and mean velocities, turbulence intensity, integral macroscale and time scale of turbulence, and spectra of the longitudinal fluctuating velocity component. It is widely accepted in the literature that verifying that the Reynold stresses increases with height is sufficient to prove the existence of the rough sublayer in a boundary layer over rough surface. As in this work Reynolds stresses were not measured, it was possible to distinguish the presence of a roughness surface through measurements and comparisons of mean velocities and statistical values of the longitudinal fluctuating component of the mean flow at different heights. It was verified that the velocity field in an urban centre is clearly three-dimensional and that the direction of the background wind has influence on the velocity field. Furthermore, a power spectrum for the dynamic analysis of tall buildings exposed to wind in urban environments is suggested as well as guidelines regarding the variation of both the velocity and turbulence intensity of the longitudinal component of the turbulence. Loads over two models were studied in order to analyse the reliability of the loads suggested by codes of Argentina e Brasilero. The models had different heights and loads were measured with the models isolated and in six situations of different rough urban environments. The loads that were measured were longitudinal-to-the-mean-flow and transversal-to-themean- flow bending and torsion moments. With these results it was possible to assess the differences with regard to loads suggested by the code NBR 6123 and CIRSOC 102 and the variations appearing when changing the surface roughness.
Arnqvist, Per. "Functional clustering methods and marital fertility modelling." Doctoral thesis, Umeå universitet, Institutionen för matematik och matematisk statistik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-130734.
Full textLim, Sungtaek. "The improvement of meter performance of EM sensing flowmeters using software modelling." Thesis, Cranfield University, 2008. http://hdl.handle.net/1826/3751.
Full textWadge, Edmund. "The use of EM-based neural network schemes for modelling and classification." Thesis, University of Westminster, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434417.
Full textSOUZA, Naiara Meireles de. "Modelo multicritério para política de inspeção em pavimentos utilizando Delay Time Modelling." Universidade Federal de Pernambuco, 2017. https://repositorio.ufpe.br/handle/123456789/25051.
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O estado de conservação de pavimentos asfálticos pode interferir diretamente no desgaste de veículos e aviões, bem como na segurança de seus usuários. A principal função requerida pelas aeronaves sobre pavimentos asfálticos de aeródromos relaciona-se ao processo de pousos e decolagens. Assim, para que operações de complexos aeroportuários sejam exercidas de maneira adequada é demandado infraestrutura que considere especialmente a movimentação das aeronaves. Por isso, os revestimentos asfálticos são considerados um dos principais componentes estruturais de aeroportos juntamente com suas instalações e equipamentos. Desse modo, a conservação dos pavimentos asfálticos gera um impacto direto na disponibilidade e custo de operações. Assim, a manutenção de pavimentos apresenta-se como um problema não somente do modal rodoviário, mas também do modal aéreo, uma vez que a deterioração de pavimentos, seja por fatores climáticos ou operacionais, apresenta-se como um dos fatores mais recorrentes de incidentes em solo envolvendo aviões. Atrelado a esse contexto, essa pesquisa sugere um modelo multicritério envolvendo uma política de inspeção em pavimentos utilizando o Delay Time Modelling com o intuito de determinar o período ótimo de inspeções e manutenção preventiva em um aeroporto brasileiro localizado na região Nordeste, visando o critério de custo e disponibilidade das operações do aeródromo. Os pavimentos asfálticos estão sujeitos a uma série de defeitos e falhas, sobretudo buracos advindos da propagação das trincas. Desse modo, os buracos foram considerados o objeto de estudo por serem os que mais despendem de tratativas de manutenção em pavimentos. O modelo proposto objetivou sugerir o intervalo ideal de inspeção e de ações preventivas de manutenção com foco no custo e na disponibilidade por meio de coleta de dados objetivos e subjetivos de acordo com o conhecimento a priori de especialista. Além disso, através da aplicação da Teoria da Utilidade Multiatributo foi possível encontrar a maior função utilidade e determinar o intervalo ideal de inspeção de modo que o critério custo e disponibilidade pudessem ser desempenhados ao mesmo tempo.
The asphalt pavements conservation status can directly interfere the utilization of vehicles and aircrafts and consequently in the safety of its users. The main function required by an aircraft on asphalt pavements of aerodromes is related to the landings and take-offs processes. Therefore, for the airport complexes’ operations to be properly carried, it is required an infrastructure that especially considers the movement of the aircrafts. For that reason, asphalt coatings are considered one of the main structural components of the airports, along with its facilities and equipments the good conservation of asphalt pavements generates a direct impact on the availability and cost of the airports operations. Thus, the maintenance of pavement is not only a road transport problem but also to the air transport, since the deterioration of pavements, either by weather or operational factors, is one of the recurring factors responsible for incidents involving aircrafts on the ground. Related to this context, this research suggests a multi-criteria model involving a pavement inspection policy, using the Delay Time Modeling, in order to establish the optimal period of inspections and preventive maintenance in a Brazilian airport located in the Northeast area, aiming the cost and availability of aerodrome operations criteria. The asphalt pavements are the main cause to a set of defects and failures, particularly the holes arising from the propagation of cracks on its structure. As a consequence, the holes were considered the object of this study because they are the ones that most demand maintenance interventions. The proposed model aimed to suggest the optimal intervals for both inspection and preventive maintenance actions focusing on cost and availability through the collection of objective and subjective data according to a priori expert knowledge. Moreover, by applying the Multiattribute Utility Theory it was found the greater utility function and determined the optimal inspection interval, so that the cost and availability criteria could be simultaneously performed.
Aparecido, Lucas Eduardo de Oliveira. "Modelos agrometeorológicos para previsão de pragas e doenças em Coffea arabica L. em Minas Gerais /." Jaboticabal, 2019. http://hdl.handle.net/11449/190699.
Full textResumo: O café é a bebida mais consumida no mundo e uma das principais causas para a redução da produtividade e qualidade são os problemas fitossanitários. A estratégia mais comum de controle dessas doenças e pragas é a aplicação de fungicidas e inseticidas foliares, dependendo da intensidade dos mesmos na região. Esse método tradicional pode ser melhorado utilizando de sistemas de alertas por meio de modelos de estimativas dos índices de doenças e pragas. Este trabalho tem como OBJETIVOS: A) Calibrar as variáveis meteorológicas: temperatura do ar e precipitação pluviométrica do sistema ECMWF em relação aos dados de reais de superfície mensurados pelo sistema nacional de meteorologia (INMET) para o estado de Minas Gerais; B) Avaliar quais os elementos meteorológicos exercem maior influência nas principais pragas (broca e bicho-mineiro) e doenças (ferrugem e cercosporiose) do cafeeiro arábica nas principais localidades cafeeiras do Sul de Minas Gerais e do Cerrado Mineiro; C) Desenvolver modelos agrometeorológicos para previsão de pragas e doenças em função das variáveis meteorológicas usando algoritmos de machine learning e procurando uma antecipação temporal suficiente para tomada de decisões. MATERIAL E MÉTODOS: Para o objetivo “A” foram utilizados dados climáticos mensais de temperatura do ar (T, ºC) e precipitação pluviométrica (P, mm) provenientes do ECMWF e do INMET no período de 1979 a 2017. A evapotranspiração potencial foi estimada por Thornthwaite (1948) e balanço hídrico p... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Coffee is the most consumed beverage in the world, but phytosanitary problems are amongst the main causes of reduced productivity and quality. The application of foliar fungicides and insecticides is the most common strategy for controlling these diseases and pests, depending on their intensity in a region. This traditional method can be improved by using alert systems with models of disease and pest indices. This work has as OBJECTIVES: A) To calibrate the meteorological variables: air temperature and rainfall of the European Center for Medium Range Weather Forecast (ECMWF) in relation to the real surface data measured by the national meteorological system (INMET) for the state of Minas Gerais; B) To evaluate which meteorological elements, and at what time, have a greater influence on the main pests (coffee borer and coffee miner) and diseases (coffee rust and cercosporiosis) of Coffee arabica in the main coffee regions of the South of Minas Gerais and Cerrado Mineiro; C) To develop agrometeorological models for pest and disease prediction in function of the meteorological variables of the South of Minas Gerais and Cerrado Mineiro using algorithms of machine learning with sufficient temporal anticipation for decision making. MATERIAL AND METHODS: To achieve goal "A" we used monthly climatic data (T, ºC) and rainfall (P, mm) from the ECMWF and INMET from 1979 to 2015. Potential evapotranspiration was estimated by Thornthwaite (1948) and water balance by Thornthwaite and Mathe... (Complete abstract click electronic access below)
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Li, Shikun. "Network Exceptions Modelling Using Hidden Markov Model : A Case Study of Ericsson’s DroppedCall Data." Thesis, Uppsala universitet, Statistiska institutionen, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-251382.
Full textKruger, Neil. "Modelling the EM properties of dipole reflections with application to uniform chaff clouds." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2317.
Full textENGLISH ABSTRACT: The origin of chaff dates as far back as WWII, acting as a passive EM countermeasure it was used to confuse enemy radar systems and is still in use today. The purpose of this study is, firstly, to build up a knowledge base for determining chaff parameters and secondly, to calculate the theoretical Radar Cross Section (RCS) of a chaff cloud. Initially dipole resonant properties are investigated relative to dipole physical dimensions. This is extended to the wideband spatial average RCS of a dipole with application to chaff clouds. A model is developed for calculating the theoretical RCS of a cloud typically produced by a single, multiband chaff cartridge. This model is developed on the principles of sparse clouds with negligible coupling; the dipole density for which the model is valid is determined through the statistical simulation of chaff clouds. To determine the effectiveness of chaff clouds, the E-field behaviour through a chaff cloud is investigated numerically. From simulation results a model is developed for estimating the position and drop in E-field strength. It is concluded that though it would be possible to hide a target behind a chaff cloud given ideal circumstances, it is not practical in reality. Given the presented results, recommendations are made for future work.
AFRIKAANSE OPSOMMING: Die oorsprong van kaf dateer so ver terug as WOII. Dit was gebruik as ‘n passiewe EM teenmaatreël teen vyandelike radar stelsels en is steeds vandag in gebruik. Die doel van hierdie studie is eerstens, om ‘n kennisbasis op te bou vir die bepaling van kaf parameters en tweedens, om die teoretiese RDS van kafwolke te bereken. Aanvanklik word die dipool resonante eienskappe ondersoek relatief tot die dipool dimensies. Die studie word uitgebrei tot die wyeband ruimte gemiddelde RDS van ‘n dipool met toepassing op kafwolke. ‘n Model word ontwikkel om die teoretiese RDS te bereken vir ‘n tipiese kafwolk geproduseer deur ‘n enkele, multi-band kafpakkie. Die model is gegrond op die beginsels van lae digte kafwolke met weglaatbare koppeling; die dipool digtheid waarvoor die model geldig is, is bepaal deur statistiese simulasie van kafwolke. Om die effektiwiteit van kafwolke te bepaal, word die E-veld gedrag deur kafwolke numeries ondersoek. Vanaf simulasie resultate word ‘n model ontwikkel om die ligging van, en daling in E-veld sterkte af te skat. Daar word tot die gevolgtrekking gekom dat, alhoewel dit moontlik is om ‘n teiken agter ‘n kafwolk te versteek in ideale omstandighede, dit nie prakties is nie. Na aanleiding van die resultate verkry, is aanbevelings vir verdere werk gedoen.
Pereira, Gonçalo André Nunes. "Modelling sovereign debt with Lévy Processes." Master's thesis, Instituto Superior de Economia e Gestão, 2014. http://hdl.handle.net/10400.5/7611.
Full textPropomos modelizar o risco de crédito soberano de cinco países da zona Euro (Portugal, Irlanda, Itália, Grécia e Espanha) seguindo uma abordagem estrutural de primeira passagem em que o movimento Browniano geométrico é substituído por um processo de Lévy regido apenas por uma componente de saltos. Deste modo, introduzimos incrementos assimétricos e leptocúrticos e a possibilidade de incumprimento instantâneo, removendo assim algumas das principais limitações do modelo Black-Scholes. Calculamos a probabilidade de sobrevivência como preço de uma opção barreira discreta, utilizando um método de valorização de opções baseado na aproximação da densidade de transição como expansão em série de Fourier de cossenos. Assumindo uma taxa de recuperação determinística, calibramos o modelo de Lévy Carr-Geman-Madan-Yor (CGMY) utilizando spreads de Credit Default Swaps semanais e obtemos a estrutura temporal de probabilidades de incumprimento. Tiramos ainda partido da representação do processo Variance Gamma (uma instância do modelo CGMY) como movimento Browniano modificado temporalmente para considerar uma estrutura de dependência entre os riscos de crédito soberanos através de uma modificação temporal comum. Em seguida, ilustramos um possível procedimento de calibração multidimensional e obtemos a distribuição de sobrevivência conjunta via simulação.
We propose to model the sovereign credit risk of five Euro area countries (Portugal, Ireland, Italy, Greece and Spain) under a first passage structural approach, replacing the classical geometric Brownian motion dynamics with a pure jump Lévy process. This framework caters for skewness, fat tails and instantaneous defaults, thus addressing some of the main drawbacks of the Black-Scholes model. We compute the survival probability as the price of a discrete barrier option, using an option pricing method based on the approximation of the transition density as a Fourier-cosine series expansion. Assuming a deterministic recovery rate, we calibrate the Carr-Geman-Madan-Yor (CGMY) Lévy model to weekly Credit Default Swaps data and obtain the default probability term structure. By drawing on the representation of the Variance Gamma process (a particular instance of the CGMY model) as a time-changed Brownian motion, we accommodate dependency between sovereigns via a common time change. We then illustrate a possible multivariate calibration procedure and simulate the joint default distribution.
Rinaldo, Guilherme. "Modelling and control of multiple mobile robots in formation." reponame:Repositório Institucional da UFABC, 2017.
Find full textDissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Mecânica, 2017.
O presente trabalho trata do controle de multiplos robos moveis enquanto mantem uma formação, atraves do uso do metodo de controle State-Dependent Riccati Equation. Seis robos com chassi diferencial são utilizados em um esquema onde um é considerado o lider e os outros cinco são considerados seguidores. Alterando parametros de formação, este trabalho busca obter cinco formações diferentes: Triangular, Echelon, Linha, Coluna e Quadrangular. Um painel de controle foi criado e simulações foram feitas utilizando o software LabVIEW, demonstrando o sucesso da aplicação do metodo de controle no problema de rastreamento de robos moveis em formação. Este trabalho tambem propõe estrategias anti-colisão para prevenir choques tanto com obstaculos quanto com outros robos. Um algoritmo é criado e implementado com sucesso para evitar colisões.
Malarranha, Jorge Manuel Carvalho. "Modelação dinâmica da performance em basquetebol." Master's thesis, Universidade de Évora, 2011. http://hdl.handle.net/10174/14123.
Full textGrün, Bettina, and Kurt Hornik. "Modelling human immunodeficiency virus ribonucleic acid levels with finite mixtures for censored longitudinal data." Wiley, 2012. http://epub.wu.ac.at/3708/1/j.1467%2D9876.2011.01007.x.pdf.
Full textNicolao, Mariano. "Adaptação em um curso na web usando workflow." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2004. http://hdl.handle.net/10183/15322.
Full textThe use of the Web with educational and training objectives may be identified as one of the great research and application areas of computer science today. The workflow technology will be able to contribute decisively for the quality of the Web courses, allowing the information to be presented in interactive way leading the apprentice to a dynamic attitude, transforming the content management into an active element that manipulates the resources in the desired sequence and speed, contributing for a more efficient learning. The use of dynamic workflows associated the agent technology supplies the potential of a nonlinear navigation, where the user takes profit of system flexibility to determine the flow of presentation of the information, not tied with a sequential chain of contents or a hierarchical structure as they have being constructed. In this context, the present work, develop a student model specified through a workflow model. This model was reached by the analysis of the interactions of a sample of students in a Web course. The Cognitive Theory of the Styles of Learning and the order of execution of the activities of the course for the students have being considered in the model development. The purpose of this workflow modelling was to contribute in the development of a comprehensive model of activities execution, coordination, monitoring and adaptation in courses in the Internet.
Gomes, Wellington Lacerda. "Integração de modelos energéticos e de balanço populacional para simulação de moagem em moinhos de bolas." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3134/tde-30122014-104754/.
Full textThe Bond method for ball mil designing has been used for 60 years. Based on Work Index test such method is applied mostly in traditional circuit configuration, which includes multi-staged crushing, followed by rod and ball milling. On the other hand simulation is a well spread and used technique for comminution and classification modeling and simulation. Even though both methods are complementary there is no effective integration between them. This work shows a technique designed to integrate both energy and modeling approaches for ball mill designing. The work is based on industrial data survey results, as well as on laboratory testing, the latter developed specifically for such a purpose. The technique will be validated under an industrial environment for assessing the obtained results.
SOUZA, Cléclio Feitosa de. "Modelling and Integrating Formal Models: from Test Cases and Requirements Models." Universidade Federal de Pernambuco, 2007. https://repositorio.ufpe.br/handle/123456789/2633.
Full textA especificação formal de um sistema ou seu modelo formal é uma forma abstrata de representar suas propriedades (características). Métodos formais é um ramo da Engenharia de Software com foco no desenvolvimento de sistemas tendo uma especificação formal do mesmo como ponto de partida. Inicialmente, as vantagens de usar notações abstratas antes da implementação do sistema estavam apenas relacionadas a um melhor entendimento do problema. Depois, tornou-se evidente que o uso de notações formais abstratas combinadas com técnicas de refinamentos de modelos reduzem o tempo de desenvolvimento e aumentam a qualidade do produto de sistema. A fase de testes é positivamente influenciada pelo uso de métodos formais. Pesquisas têm sido desenvolvidas para melhorar a qualidade do sistema usando modelos formais e casos de teste. Uma vez verificadas as propriedades do sistema através de uma investigação dos modelos formais, é possível gerar casos de testes confiáveis do sistema que serão colocados em ação para verificar a implementação do sistema posteriormente. O campo de pesquisa que explora métodos formais aplicados com testes de software é chamada de Testes Baseados em Modelos, ou simplesmente MBT, do inglês Model-Based Testing. Porém, há situações onde não é possível possuir o modelo abstrato definido a priori. Para superar tal restrição outras técnicas surgiram para sintetizar um modelo abstrato seguindo apenas execuções do sistema. As execuções de um sistema contêm comportamentos necessários para construir um modelo abstrato desse sistema. Na literatura atual, tais técnicas usadas para construir representações abstratas seguindo execuções do sistema são chamadas de Anti-Model- Based Testing ou simplesmented Anti-MBT. Então, depois de construir um modelo abstrato, técnicas de verificação de modelos e geração de casos de teste seguindo modelos formais podem ser aplicadas normalmente. O propósito desse trabalho é dar suporte a algumas técnicas de MBT usadas no contexto da Motorola (CIn/BTC). Em tais técnicas, as especificações usadas para gerar casos de testes são geralmente incompletas, inconsistentes, e às vezes não existem. Portanto, usando casos de testes reais do sistema é possível criar novas especificações e atualizar especificações originais do sistema, e posteriormente gerar novos casos de teste usando comportamentos válidos do sistema. Um outro problema detectado em nosso contexto é a distância existente entre as representações abstratas e reais. Um caso de teste abstrato, por exemplo, é útil em técnicas formais, mas não é possível executar um caso de teste diretamente no sistema. Dessa forma, para executar (manualmente ou automaticamente) os casos de teste gerados pelas técnicas de MBT é necessário primeiro traduzi-los em uma representação real. Como resultado desse trabalho nós desenvolvemos técnicas formais de modelagem do comportamento do sistema usando casos de teste. Os resultados das técnicas de modelagem são modelos formais especificados nos formalismos de LTS ou CSP. Além disso, nós definimos uma técnica de unificação que une modelos formais gerados a partir de diferentes artefatos do sistema (requisitos e casos de teste). O resultado da técnica de unificação é um completo e unificado modelo do sistema, que contém informações providas de diferentes artefatos. Nós também definimos uma técnica para traduzir casos de teste abstratos em representações reais. Os casos de teste reais gerados por nossa técnica de tradução são usados no contexto do time de automação de testes da Motorola, onde esse trabalho está inserido. Finalmente, nós automatizamos as técnicas desenvolvidas usando linguagens de programação e especificações formais. O resultado é a ferramenta TCRev que é capaz de modelar, unificar e traduzir modelos do sistema. A ferramenta TCRev interage com o outras ferramentas externas, tais como FDR e FDR Explorer. Todos os resultados foram validados em estudos de casos reais executados no contexto da Motorola. Nessa dissertação nós apresentamos um destes estudo de casos
Dias, Pedro Daniel Pinto Pereira. "O escorrimento ao longo do tronco em olivais tradicionais e super-intensivos." Master's thesis, ISA/UL, 2014. http://hdl.handle.net/10400.5/8255.
Full textStemflow (Sf) is responsible for a localized water and solute input to soil around tree’s trunks, with this effect playing an important eco-hydrological role in forested and agricultural ecosystems. Stemflow was study over 7 months in 25 trees of Olea europaea L. distributed in three olive groves in the regions of Lisboa e Santarém. The amount of Sf measured in each trees ranged from 7,5 to 87,2 mm, corresponding to 1,2 to 16,7% of gross precipitation. Linear regression models were fitted between Sf and the main meteorological variables and morphological tree characteristics. The more relevant explanatory variables were gross rainfall amount and intensity, and tree and trunk heights. There were significant differences in the dimensions of leaves between varieties and between trees of the same varieties. The differences do not seem to affect the amount of Sf generated. Through analysis of bark storage capacity, it was found that older trees, with rough and deep bark, had higher trunk storage capacity and, therefore, originated less Sf. We also tried to relate the funnelling ratio (FR) with some selected characteristics. Only one acceptable linear relationship between the FR and the volume of precipitation was found
Lago, Paulo Jakson Assunção. "Processos físicos e propriedades cinemáticas em nebulosas planetárias extensas." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/14/14131/tde-16062018-104540/.
Full textPlanetary Nebulae (PNe) are consequence of the stellar evolution process of intermediate mass stars, they form due the mass-ejection at the post-AGB phase. The interaction of the ejected gas in dierent mass-loss episodes shapes their morphology, as described by the interacting winds theory. The morphological diversity of PNe remains a subject of intense debate, their formation scenarios are still opened and hydrodynamical simulations still have little use. For a particular target, structure reconstruction and description of the kinematics are very useful. By using images and spectroscopical data, structures for a sample of PNe are reconstructed, the observational data are modeled, what allows a series of conclusions about the objects, including their formation scenarios. Using data from OPD (Pico dos Dias Observatory), as well as from the SPM survey, we constructed models for five PNe, the role of shocks in the ionization and excitation mechanisms were studied as well, based on the models for shocks available in the literature. Our models are based on simple structures, most of them symmetrical. All velocity fields are linear and density distributions aim to reproduce the surface brightness. The reproduced data are P-V (position - velocity) diagrams. We modeled NGC 6818, NGC 6153 and NGC 3211, reproducing their P-V diagrams appropriately. For NGC 6818 e NGC 6153, we found that shocks are relevant, what was not expected. NGC 2440 was reproduced with two bipolar components, its central region consists in a torus fragmented in at least three pieces. By using the kinematical properties of the central region, a distance of 1.8 kpc was derived to this nebula. A non-concentrical spherical halo involves the whole structure, and the shocks dominate the ionization and excitation process at the rims of this object. NGC 6445 was modeled as a multipolar PN with four bipolar components, a central toroidal structure completes the model. We conclude that the central rectangle visible in the images of this object is a consequence of an overlap of structures. Within this scenario for NGC 6445, combined with the analysis of shocks in NGC 6302, we suggest that the shocks have to be considered in abundance estimates of type I PNe, since they may have an impact on the ionization correction factors.
MUCHANGA, Armando. "Estudo e análise de confiabilidade e manutenção em pavimentos asfálticos: uma abordagem delay time modelling." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/17626.
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O desenvolvimento urbano depende de vários setores, e o mais importante, além de mais caro nos custos de urbanização é o setor de infraestrutura de transporte, responsável pela pavimentação e manutenção das vias. Com o aumento acelerado de veículos que trafegam nas vias, para um departamento de transporte manter uma rede viária urbana sob os níveis de desempenho requeridos ao longo da vida útil do pavimento é necessário que haja um melhor gerenciamento das atividades de manutenção. De todos os tipos de defeitos dos pavimentos, os que mais preocupam os usuários das vias, gestor e os técnicos da manutenção são os buracos. Alinhada a este fato exposto, esta dissertação propõe um modelo Delay Time para determinar o período ótimo de inspeção e manutenção preventiva dos pavimentos asfálticos urbanos, em particular das vias da cidade de Recife, de modo a minimizar os custos de manutenção. Primeiro são exploradas as abordagem de modelo Delay Time, para analisar a que se adequa aos pavimentos asfáltico. E a abordagem proposta é Delay Time do sistema complexo, sujeito a várias falhas, com inspeção perfeita e taxa de chega de defeitos homogênea. Os pavimentos são sujeitos a vários tipos de defeitos, mas este trabalho considerou os buracos por serem os defeitos que mais gastam no custo de manutenção. Também é feita uma revisão dos trabalhos que contribuíram para investigação e aplicação do modelo Delay Time. Ainda neste trabalha é apresentado uma revisão das normas dos pavimentos asfáltico, bem como a politica de manutenção “Operação Tapa-Buraco” praticada atualmente nas vias da cidade de Recife para tapar os buracos. O modelo proposto mostra se viável e não é sensível quando variam os parâmetros de entra, os resultados obtidos são fáceis de aplicar se o setor de manutenção de pavimento da cidade de Recife incluir as hipóteses do modelo na “Operação Tapa-Buraco”.
The urban development depends on several sectors, the most important, beyond most expensive, comes from the transport infrastructure sector - that is responsible for paving and maintenance of roads. Due the rapid increase of vehicles on roads, for the transport department to keep an urban road network under the performance levels required it is necessary to invest in a better management of maintenance activities. Among all types of floors of defects, the primary concern to road users, managers and maintenance technicians are the holes. In sum to this stated fact, this dissertation proposes a Delay Time model to determine the optimal period of inspection and preventive maintenance of urban asphalt pavements, particularly for the roads of the city of Recife, in order to minimize maintenance costs. First it was explored the Delay Time model approach to analyse which applies to the asphalt pavements. The proposed approach is Delay Time of complex system, subject to several failures, with perfect inspection and a homogeneous rate of defects arrival. Besides the floors being subject to various types of defects, this work only considers holes as defects that cause more impact on the maintenance cost. It is also made a review of the works that contributed to research and application of Delay Time Models. Also in this work is presented a review of the standards of asphalt pavements, as well as the maintenance policy "Operação Tapa-Buraco", currently practiced in Recife city roads to slap the holes. The proposed model shows that it is viable and is not sensitive when varying input parameters, the results are easy to apply to the Recife city pavement maintenance industry including the model assumptions in "Operação Tapa-Buraco".
Mileo, Paulo Graziane MendonÃa. "UtilizaÃÃo da simulaÃÃo molecular na prediÃÃo da acumulaÃÃo de alcanos em estruturas metalorgÃnicas." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11829.
Full textO gÃs natural, cuja maior parte à constituÃda de metano, à um combustÃvel que vem se expandindo no mercado energÃtico global por possuir uma queima mais limpa que outros derivados petrolÃferos e por ser mais eficiente energeticamente. No entanto, ele possui como grande desvantagem frente a outros combustÃveis a dificuldade em ser armazenado devido a sua baixa densidade. Materiais microporosos vÃm sendo utilizados para aumentar tal densidade por meio da adsorÃÃo. No entanto, um dos problemas encontrados na utilizaÃÃo desses materiais se trata da diminuiÃÃo da capacidade adsortiva apÃs ciclos de carga e descarga de tanques de armazenamento. O estudo desse problema, porÃm, demanda um grande nÃmero de experimentos e uma aparelhagem relativamente sofisticada. Este trabalho propÃs a simulaÃÃo molecular como uma metodologia vÃlida a ser utilizada para o estudo da retenÃÃo de alcanos em carbono ativado e em oito estruturas metalorgÃnicas: IRMOF-1, ZIF-8, CuBTC, PCN-11, PCN-14, UiO-66, MIL-100 e MIL-101. Considerou-se o gÃs natural como uma mistura de metano (C1), etano (C2), propano (C3) e butano (C4) nas proporÃÃes de, respectivamente, 84,7:10:0,9:0,1. Para a validaÃÃo dos modelos utilizados nassimulaÃÃes, as isotermas simuladas de C1, C2, C3 e C4 foram ajustadas Ãs experimentais obtidas da literatura para cada um dos materiais. Foram entÃo realizadas isotermas multicomponentes e estudo de sÃtios de adsorÃÃo para o estudo da retenÃÃo de hidrocarbonetos e da influÃncia de fatores composicionais e estruturais nesse fenÃmeno. Observou-se que as MOFs MIL-100 e ZIF-8 sÃo as mais recomendadas para uso em tanques de GNA por critÃrios de capacidade, eficiÃncia adsortiva e estabilidade. Verificou-se ainda que MOFs que apresentam sÃtios de adsorÃÃo pouco dispersos apresentam uma maior tendÃncia à acumulaÃÃo de hidrocarbonetos.
Natural gas, which consists mostly of methane, is a fuel that has been expanding in the global energy market by having a cleaner burning than other petroleum derivatives and are more energy efficient. However, it has a great disadvantage compared to other fuels: it is difficult to be stored due to its low energy density. Microporous materials have been used to increase the energy density by adsorption. However, one of the problems encountered in using these materials it comes to the decrease in adsorption capacity after charge and discharge cycles of the storage tanks. The study of this problem, however, requires a large number of experiments and a relatively sophisticated equipment. This paper proposes themolecular simulation as a valid methodology to study the retention of alkanes in activated carbon, and eight metalorganic structures: IRMOF - 1, ZIF - 8, CuBTC, PCN- 11, PCN -14, UiO -66, MIL -100 and MIL- 101. We considered the natural gas as a mixture of methane (C1), ethane (C2), propane (C3) and butane (C4) in the proportions respectively 84,7:10:0,9:0,1. For the validation of the models used in the simulations, the simulated isotherms of C1, C2, C3 and C4 were adjusted to fit the experimental ones, obtained from the literature data for every material. Multicomponent isotherms were then performed, the retention of hydrocarbons were studied as well as the influence of compositional and structural factors to this phenomenon. We noticed that the MOFs MIL-100 and ZIF-8 are the most recommended to use in GNA tanks according to the criteria of capacity, adsorption efficiency and stability. We verified as well that MOFs that have adsorption sites too localized present a larger tendency to the accumulation of hydrocarbons.
Vivanco, Pezantes David. "Estudo das operações combinadas da desidratação osmotica a vacuo : defumação liquida e secagem em files de bonito (sarda sarda)." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255147.
Full textTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Doutorado
Doutor em Engenharia de Alimentos
Silva, Alexandre José da. "Aspectos da modelagem em SYSML ligados à seleção de processador para sistema embutido." Florianópolis, SC, 2006. http://repositorio.ufsc.br/xmlui/handle/123456789/88892.
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Existe atualmente uma enorme variedade de equipamentos específicos cujo controlador microprocessado está embutido nos mesmos. Tais sistemas computacionais são embutidos como componentes dentro de um sistema maior. Na perspectiva da computação, tais sistemas são conhecidos como sistemas computacionais embutidos (embedded computer system), ou simplesmente sistemas embutidos (embedded systems). A grande maioria dos sistemas embutidos são programados e incluem componentes de hardware e de software. Para suportar o projeto de tais sistemas uma nova metodologia de projeto vem sendo desenvolvida denominada hardware/software co-design. Além do hardware/software co-design, é muito importante uma metodologia que leve a seleção do elemento de processamento ideal para a realização da tarefa específica do sistema embutido. O aumento de complexidade e variedade dos equipamentos com processador embutido gera a necessidade de uma abordagem interdisciplinar no processo de desenvolvimento desses equipamentos, envolvendo as áreas de engenharia de software, mecânica, elétrica e eletrônica. Neste sentido, está sendo especificada pela OMG uma linguagem de modelagem, denominada SysML (System Modelling Language), que pretende incluir em uma única especificação uma visão integrada do sistema, incluindo hardware, software e partes eletro-mecânicas. A dissertação faz um levantamento dos métodos e critérios empregados na seleção do processador a ser utilizado em um sistema embutido. As sugestões e métodos presentes na literatura são descritos, classificados e analisados. São modelados dois estudos de casos utilizando a linguagem de modelagem SysML. A partir da modelagem é realizada uma avaliação prática da atual proposta da linguagem SysML, no sentido de identificar suas capacidades e suas limitações na modelagem de sistemas embutidos, são analisados as possibilidades de extração das informações relevantes à seleção do processador embutido.
Júnior, Valdemar Lacerda. "Aplicações de técnicas de RMN à determinação estrutural de intermediários sintéticos." Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/59/59138/tde-02102001-115811/.
Full textThe well known W rule, which establishes that nuclei in a planar W arrangement exhibit significant four bond coupling constants, has been a useful tool in molecular structure determination since early times of the use of nmr spectra for this purpose. Many configurations and conformations have been decided based on this rule. The continuous evolution of the nmr equipment, however, produces modifications in quality and number of available experimental data, thus forcing the chemists to frequent revisions of their points of view about the relative importance of the data that can be obtained from nmr spectra. The more recent equipment has a higher resolution and several additional features that throw some shadow over early concepts: on one hand, the high power of modern techniques such as NOE DIFF and other multi-dimensional methods reduce the importance of coupling constants; on the other hand, it is now possible to determine many more coupling constants, due mainly to the higher resolution. A natural consequence is that the chemist can now exploit the use of subtle splittings in conformational analysis. As part of our research work on the synthesis of natural products, we have prepared a number of cyclopentane derivatives. Our attention was strongly attracted to the long-range (4JHH) coupling constants that occurred in some of these compounds, as no planar W conformation seems to be possible in cyclopentanes. We have thus decided to start a more detailed study of the nmr spectra of these compounds, seeking for more clear interpretation of the data. We have first assigned all hydrogens, including the stereochemistry of each hydrogen, and measured all J values for the compounds; for this task we have used nmr spectra both of 1H (300 MHz) and 13C (75 MHz), NOE measurements, etc. Bond angles and dihedral (torsion) angles were calculated with molecular modeling programs; several different programs and methods were used to improve reliability. The first result obtained is a confirmation that a 4JHH 'different' 0 occurs even in cases where a planar W conformation is not possible. More important, however, is the conclusion that there is a correlation between the 4JHH values and the involved dihedral angles. There are two dihedral angles in the path through the bonds between two hydrogens which show 4JHH coupling. When 4JHH values are plotted against(cos2'teta'1 x cos2'teta'2) (a simple extension of Karplus equation) the points are not aligned over a continuous curve, but they show a clear tendency: 4JHH values become higher as the angles 'teta'1 and 'teta'2 vary from 90 to 180º.
Rodrigues, Gonçalo Pereira Fernandes Caleia. "Modelação económica visando o apoio à decisão no uso e produtividade da água em regadio." Doctoral thesis, ISA, 2013. http://hdl.handle.net/10400.5/6155.
Full textImproving crop water productivity requires new approaches to economic modelling, considering alternative irrigation scheduling and irrigation systems performance. The present study aims at applying an economic modelling to water use and productivity in irrigated areas. It intends to determine the potential of irrigation systems at field scale to achieve an efficient water use, giving particular attention to maximizing the beneficial water use and the physical and economic water productivities. Thus several water-saving scenarios were developed taking into account alternative solutions to the irrigation practices adopted at the selected fields. Economic analysis and multicriteria analysis methodologies have been developed, implemented, evaluated, and incorporated in system design models (MIRRIG, PROASPER, DEPIVOT). It was possible to identify the best strategies to achieve improved water productivities using the economic modelling coupled with multicriteria analysis modules. The benefits and costs related to irrigation systems and management, through managed water demand, using deficit irrigation, and through the improvement of irrigation systems performance were also considered. The methodology developed proves to be a useful tool to support decision making at the field level, aiming at the sustainability of agricultural systems.
Braun, Tatjana [Verfasser], Gunnar [Gutachter] Schröder, and Georg [Gutachter] Groth. "Protein Structure Modelling using Evolutionary Information and Cryo-EM Data / Tatjana Braun ; Gutachter: Gunnar Schröder, Georg Groth." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2017. http://d-nb.info/1139891170/34.
Full textFILHO, Roberto Mariano de Araujo. "Análise da colaboração em situação de formação de professores de matemática online." Universidade Federal de Pernambuco, 2015. https://repositorio.ufpe.br/handle/123456789/18809.
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Esta pesquisa tem por objetivo analisar a aprendizagem colaborativa suportada por computador no contexto da formação do professor de matemática quanto ao uso de modelagem para o ensino e aprendizagem de funções. A pesquisa fundamenta-se na Aprendizagem Colaborativa com Suporte Computacional (CSCL), Caracterização das Funções e Modelagem Matemática. A metodologia de investigação conta com as fases de elaboração do ambiente virtual CSCL para propiciar: discussão das dificuldades de aprendizagem das funções, discussão e elaboração de simuladores utilizando o software Modellus, exploração da modelagem como metodologia de ensino e aprendizagem, de forma colaborativa. A situação foi estruturada tendo como momento inicial uma instrumentalização dos softwares que suportam a comunicação e interação, além do software de modelagem que permite a exploração de situações envolvendo as funções afim e quadrática, em sintonia com as discussões das teorias da CSCL. O estudo analisa o trabalho colaborativo desenvolvido por 3 grupos de licenciandos em Matemática. Os dados revelam que o grupo menor conseguiu colaborar com mais facilidade que os grupos maiores. Os dados mostram também que as discussões acerca das dificuldades dos estudantes foi onde houve maior colaboração. Além disso, o script elaborado não conseguiu direcionar os participantes sozinhos durante a atividade, precisando sempre de uma intervenção do mediador. Também foram percebidos entraves do ambiente que mostraram a necessidade da montagem de outro espaço, que pudesse oferecer recursos que facilitem a comunicação entre os participantes da sessão.
This research aims to analyze collaborative learning supported by computer in the mathematics teachers trainning course in the use of modeling for teaching and learning functions. The research framework is based on Collaborative Learning with Computer Support (CSCL), Characterization of Functions and Mathematical Modeling. The research methodology includes the design of a colaborative learning environment, preparation of CSCL virtual environment to provide: discussion of the difficulties of learning functions, discussion and development of simulators using Modellus software, exploitation of modeling as a teaching and learning methodology, collaboratively. The situation was structured taking as a starting point the instrumentalization of software programmes, the one which supports communication and interaction and Modellus, the modeling software which allows the exploration of situations involving quadratic and affine functions, considering the discussions of CSCL theory. The study analyzes the collaborative work of three undergraduates groups of students. The data shows that the smaller group collaborated more easily than larger groups. The data also show that discussions about the difficulties of the students was where there was greater collaboration. In addition, the script written could not direct participants themselves during the activity, always in need of a mediator intervention. Also some environmental barriers were showed the need to rethink the virtual space, which could provide resources to facilitate communication between participants in the session.
Sales, e. Silva José Gilson. "Equações de diferenças finitas na modelagem da hanseniase em Imperatriz - MA." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/306485.
Full textDissertação (mestrado profissional) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica
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Resumo: Apresentamos uma abordagem resumida da epidemiologia matemática, dos modelos epidemiológicos tipo SI, SIS e SIR, bem como um embasamento sobre as equações de diferenças finitas. Utilizamos um modelo matemático determinístico em tempo discreto tipo SI, simplificado, para interpreta¸c¿ao e análise da epidemia de hanseníase do município de Imperatriz-MA, com base em dados relativos ao número de contatos registrados e casos notificados no per'iodo de 1994 a 2007. Apresentamos também uma validação do modelo e histórico da epidemia em Imperatriz.
Abstract: We present an approach summarized from epidemiology mathematics , from the models epidemiological type Oneself SI SS e SIR , as well as a basement on the subject of the equations of differences finite. Uses a model mathematical deterministic in time discreet type SI about to interpretation e analysis from epidemics from hansen'iase of the county of Imperatriz-MA , based on dice relative the number of contacts registered e cases notifying into the period of 1994 the 2007. We present also a validation of the model e historical from epidemics in the Imperatriz.
Mestrado
Biomatematica
Mestre em Matemática
Fragoso, Júnior Carlos Ruberto. "Modelagem tridimensional da estrutura trófica em ecossistemas aquáticos continentais rasos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/18926.
Full textThis thesis identified several important features of the trophic structure and dynamics of nutrients in ecosystems subjected to external disturbances such as changes in the water level, nutrient and organic matter loading, fish communities and climate. To describe such effects on trophic structure, a complex ecological model, based on physical, chemical and biological processes has been developed and applied in tropical, subtropical and temperate aquatic ecosystems. In such applications, an integrated analysis was employed considering the transfer of impacts from the watershed to the ecosystem, in order to bring closer the understading of the ecosystem dynamics. Simulations revealed important features about system structure and functionality in front of disturbances. For instance, lake Mangueira a subtropical lake in Southern Brazil can oscilate between two alternative steady stables (clear or turbid water), depending orthophosphate concentration and water transparency. It was also suggested that can occurs profound changes in phytoplankton composition from increase of orthophosphate concentration. Horizontal and vertical gradients in the trophic structure are notable in lake Mangueira, indicating the importance to consider spatial heterogeneity in large lakes to improve understanding of ecological processes and patterns. Simulation scenarios indicated that increased nutrient loading negatively affects water transparency, differently from climate changes. Slight changes in trophic structure caused by those factors indicate a strong resistence of the lake Mangueira. The ecological model also was useful to describe the ecosystem dynamics before and after biomanipulation of lake Engelsholm located in Denmark. In that case, the model could reasonably well predict a shift to a clear water state, but the changed composition of phytoplankton functional groups was much more hard to represent. Furthermore, simpler applications also provided support for decision making and planning in the ecosystem. Ecological modeling applied in aquatic ecosystems showed be a promising alternative towards the integrated management of natural resources.
Medeiros, Pedro Henrique Augusto. "Processos hidrossedimentolÃgicos e conectividade em bacia semiÃrida: modelagem distribuÃda e validaÃÃo em diferentes escalas." Universidade Federal do CearÃ, 2009. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=4425.
Full textA deficiÃncia hÃdrica em regiÃes semiÃridas, como o Nordeste do Brasil, representa um dos principais fatores limitantes ao desenvolvimento econÃmico, com graves consequÃncias sociais. Para garantir a conservaÃÃo dos recursos hÃdricos disponÃveis, à imprescindÃvel o controle de aÃÃes antrÃpicas que impactem negativamente a disponibilidade hÃdrica. Por exemplo, a ocupaÃÃo desordenada do solo e a utilizaÃÃo de prÃticas inadequadas na agricultura intensificam a erosÃo e o transporte de sedimentos, interferindo diretamente na disponibilidade hÃdrica. O assoreamento de reservatÃrios causa a reduÃÃo de sua capacidade de armazenamento e, consequentemente, sua capacidade de regularizar vazÃes com elevada garantia. O aporte de sedimentos a mananciais contribui tambÃm para a degradaÃÃo da qualidade da Ãgua, atravÃs do aumento da turbidez, o que provoca a reduÃÃo da concentraÃÃo de oxigÃnio dissolvido, e do enriquecimento de nutrientes. Adicionalmente, a erosÃo do solo à um dos principais fatores de degradaÃÃo ambiental, provocando a perda de nutrientes das camadas superficiais de solo. Portanto, uma avaliaÃÃo precisa dos fluxos de sedimento ao longo de sua trajetÃria à imprescindÃvel para a identificaÃÃo de Ãreas potencialmente erosivas e de locais onde predominam processos de deposiÃÃo. Para isso, faz-se necessÃrio o conhecimento das condiÃÃes de transporte dos sedimentos atravÃs e entre os diferentes compartimentos da bacia hidrogrÃfica. O potencial de movimento de uma partÃcula no sistema, denominado de conectividade no transporte de sedimentos, destaca-se como fator determinante para a compreensÃo e estimativa dos fluxos de massa sÃlida. De forma a se avaliar o efeito da conectividade sobre a produÃÃo de sedimentos na regiÃo semiÃrida do Brasil, realizou-se simulaÃÃo hidrossedimentolÃgica da bacia hidrogrÃfica de meso-escala do aÃude BenguÃ, CearÃ, utilizando-se o modelo WASA-SED. Constatou-se que, de um modo geral, o balanÃo de Ãgua no solo determina as condiÃÃes de geraÃÃo de escoamento na regiÃo de estudo: muito embora haja uma predominÃncia de iniciaÃÃo do escoamento superficial por processo Hortoniano, na escala de bacia hidrogrÃfica o excesso de precipitaÃÃo à percebido somente em eventos de grande magnitude ou apÃs sequÃncias de eventos chuvosos, quando a conectividade hidrolÃgica à elevada. Assim, as condiÃÃes de transporte limitam a produÃÃo de sedimentos, gerando padrÃes espaciais muito semelhantes de escoamento superficial e de produÃÃo de sedimentos. Na escala de bacia hidrogrÃfica, o padrÃo espacial de conectividade mostrou-se fortemente relacionado a caracterÃsticas hidrÃulicas do solo, enquanto que na escala de vertente, caracterÃsticas topogrÃficas locais desempenharam um papel mais importante no transporte de sedimentos. A simulaÃÃo de caracterÃsticas especÃficas do semiÃrido pelo modelo WASA-SED, tais como escoamento do tipo Hortoniano, reinfiltraÃÃo a jusante, redistribuiÃÃo lateral de escoamento e densa rede de reservatÃrios, permitiu a estimativa satisfatÃria dos fluxos de Ãgua e sedimentos tanto na bacia do Benguà (933 kmÂ) como na sub-bacia de Aiuaba (12 kmÂ). Um teste mais rigoroso foi realizado com o uso da tÃcnica de CÃsio-137 como traÃador de erosÃo/deposiÃÃo de sedimentos. A comparaÃÃo entre valores modelados e medidos com 137Cs em uma vertente representativa demonstrou boa correlaÃÃo entre os valores. Apesar de se tratar de um resultado local, tal comparaÃÃo indica que o modelo WASA-SED simule os fluxos de sedimento de maneira satisfatÃria tambÃm na escala de vertente
Water deficit in semiarid regions, such as the Northeastern Brazil, is a major limiting factor to economic development, with serious social consequences. To ensure the conservation of the available water resources, it is essential to control the human activities that impact negatively on water availability. For instance, uncontrolled soil use and improper agricultural practices, tend to intensify erosion and sediment transport processes, with direct impacts on water availability. Reservoirs siltation causes a reduction of the storage capacity and, hence, of the ability to supply water with high reliability. Sediment input to water bodies also contributes to water quality degradation, by increasing turbidity, which results in a reduction of the concentration of dissolved oxygen, and nutrient enrichment. In addition, soil erosion is a major factor of environmental degradation, causing the loss of nutrients of the top soil layers. Therefore, an accurate assessment of sediment fluxes along its pathway is essential for the identification of potentially erosive areas and regions where deposition processes predominate. For such estimation, a good understanding of the conditions of sediment transport through and between the different catchment compartments is necessary. The potential for movement of the soil particles within the system, denominated connectivity in sediment transport, stands out as a determining factor for the understanding and estimation of the flow of solid mass. In order to evaluate the effect of connectivity on sediment yield in the semiarid region of Brazil, a hydrosedimentological simulation of the Benguà meso-scale catchment (CearÃ, Brazil) was carried out with the WASA-SED model. It was found that, in general, water balance in the soil matrix determinates the conditions for runoff generation in the study area: although there is a predominance of surface runoff initiation by Hortonian process, in the catchment scale, excess precipitation is observed only in events of great magnitude or sequences of rain events, when hydrological connectivity is high. Thus, the transport conditions limit sediment yield, generating very similar spatial patterns of runoff and sediment yield. At the catchment scale, the spatial pattern of connectivity was strongly related to soil hydraulic properties, while topographic characteristics played a more important role in sediment transport at the finer scale. The simulation of specific features of semiarid regions by the WASA-SED model, such as Hortonian-type flow, downstream re-infiltration of surface runoff, lateral flow redistribution and dense network of reservoirs, allowed a satisfactory estimate of both water and sediments fluxes in the Benguà catchment (933 km Â), as well as in the Aiuaba sub-basin (12 km Â). A more rigorous test was performed with the technique of Cesium-137 as a tracer of soil erosion/deposition. A comparison between modelled and measured (with 137Cs) values in a representative hillslope showed good correlation between the values. Even though it is a local result, this comparison indicates that the WASA-SED model must be able to simulate sediment fluxes satisfactorily also in the hillslope scale
Braga, Francisco Manuel de Carvalho. "Modelação do crescimento em altura e da relação diâmetro-altura de árvores jovens de Quercus suber." Master's thesis, Universidade de Évora, 2015. http://hdl.handle.net/10174/16436.
Full textPätsi, J. (Jukka). "Catalytic core of respiratory chain NADH-ubiquinone oxidoreductase:roles of the ND1, ND6 and ND4L subunits and mitochondrial disease modelling in Escherichia coli." Doctoral thesis, Oulun yliopisto, 2011. http://urn.fi/urn:isbn:9789514294723.
Full textTiivistelmä 45 alayksiköstä muodostuva NADH-ubikinoni oksidoreduktaasi (kompleksi I) on nisäkkäiden suurimpia entsyymejä. Sen mitokondriaalisessa DNA:ssa koodattujen alayksiköiden ND1-ND6 ja ND4L geeneihin liittyvät mutaatiot ovat yleisiä mitokondriosairauksien, kuten Leberin perinnöllisen näköhermoatrofian (LHON) ja MELAS-oireyhtymän, syitä. Bakteerien vastaava entsyymi (NDH-1) koostuu vain 13–14 alayksiköstä. Tästä huolimatta sen katalysoima reaktio on samankaltainen kuin kompleksi I:n. NDH-1:n katsotaankin edustavan entsyymin katalyyttistä ydintä. Tässä työssä tutkittiin ND1, ND6 ja ND4L alayksiköiden tehtävää kompleksi I:ssä niiden Escherichia coli bakteerissa olevien vastineiden (NuoH, NuoJ ja NuoK) kohdennetun mutageneesin avulla. Samaa lähestymistapaa käytettiin LHON/MELAS-oireyhtymässä todettujen ND1 alayksikön mutaatioiden, m.3376G>A ja m.3865A>G, ja LHON:ssa havaitun ND6:n m.14498T>C mutaation aiheuttamien aminohappomuutosten seurauksien selvittämiseen. Tehtyjen mutaatioiden vaikutuksia arvioitiin entsyymiaktiivisuus-mittauksin ja kasvukokein. NuoK:n solukalvon läpäisevissä rakenteissa olevien kahden glutamaatti-aminohappotähteen sijainti muistuttaa protoneita kalvon läpi kuljettavissa proteiineissa todettua. NuoK:n glutamaattien havaittiinkin olevan tärkeitä elektronien ja protonien kuljetukselle kompleksi I:ssä. m.3376G>A ja m.14498T>C mutaatioiden aiheuttamien aminohappomuutosten vastineet NDH-1:ssä alensivat NDH-1:n elektroninsiirtoaktiivisuutta ja heikensivät ubikinonin sitoutumista, kun taas m.3865A>G mutaatiolla ei ollut vaikutusta. Muut NuoH ja NuoJ alayksiköihin tehdyt aminohappovaihdokset johtivat huonontuneeseen ubikinonin ja kompleksi I:n inhibiittoreiden sitoutumiseen. Saadut tulokset vahvistavat m.3376G>A ja m.14498T>C mutaatioiden patogeenisyyden. Ne myös osoittavat, että LHON/MELAS-oireyhtymään liitetyn mutaation biokemiallisissa vaikutuksissa yhdistyvät sekä LHON:ssa että MELAS-oireyhtymässä todettujen mutaatioiden seuraukset. Esitetyt tulokset tukevat näkemystä siitä, että ubikinonin ja kompleksi I:n välisessä vuorovaikutuksessa tapahtuva muutos on kaikille LHON:aan liitetyille mutaatioille yhteinen vaikutusmekanismi. NuoH:n, NuoJ:n ja NuoK:n kohdennetusta mutageneesista saatujen tulosten perusteella ND1 ja ND6 alayksiköt ovat osa ubikinonin sitoutumispaikkaa entsyymikompleksissa, kun taas ND4L osallistuu protoninkuljetukseen
Carareto, Natalia Daniele Dorighello 1984. "Estudo do equilibrio solido-liquido em sistemas binarios de alcoois graxos atraves da calorimetria exploratoria diferencial." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254689.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Álcoois graxos são constituintes minoritários de tecidos vegetais, sendo encontrados principalmente em ceras. São utilizados na indústria como emulsificantes, surfactantes ou emolientes. Atualmente, existem muitos estudos sobre o uso de álcoois graxos associados a ácidos graxos como substitutos do processo de hidrogenação para a fabricação de margarinas e outras emulsões. O conhecimento do equilíbrio sólido-líquido de misturas binárias de álcoois graxos é uma ferramenta importante para se entender o comportamento de misturas mais complexas. Assim, neste trabalho se objetivou construir diagramas de equilíbrio sólido-líquido de misturas binárias de álcoois graxos saturados pares contendo de oito a dezoito átomos na cadeia carbônica, a partir da calorimetria Exploratória Diferencial, com método experimental previamente utilizado por Rolemberg (2002) e Costa (2004) para ácidos graxos e triacilgliceróis. Para complementar os resultados também foram capturadas imagens de microscopia óptica com controle de temperatura. Os sistemas aqui estudados apresentaram três comportamentos diferentes da linha liquidus: no primeiro grupo estão os sistemas que apresentaram apenas o ponto eutético, no segundo aqueles com ponto eutético e ponto peritético e o último grupo exibe nenhum desses pontos. Para os sistemas que apresentaram ponto peritético, pode-se observar nas imagens de microscopia a recristalização de algumas amostras com o aumento de temperatura, o que evidencia a ocorrência da reação metatética para tais sistemas. Foram utilizados os modelos termodinâmicos para coeficiente de atividade Margules 2 e 3-sufixos e NRTL para ajuste dos dados experimentais dos sistemas que apresentaram apenas ponto eutético simples e ponto eutético e peritético e obteve-se um valor de DQM satisfatório para todos os casos. Já para o modelo preditivo UNIFAC original, os desvios com relação aos valores experimentais foram altos, o que se supõe ser proveniente de simplificações, como a hipótese de uma fase sólida pura, o que neste trabalho se mostrou inadequado
Abstract: Fatty alcohols are minor constituents of vegetal tissues, being mainly found in vegetal waxes. Fatty alcohols are used in industry as emulsifiers, surfactants or emollients agents. There are many studies about the use of fatty alcohol associated with fatty acids as substitutes for the hydrogenation process of margarine manufacturing and other edible emulsions, for example. Solid-liquid equilibrium of binary mixtures of fatty alcohols is na important tool for understanding the behavior of fatty complex mixtures. Thus, this work aimed to study diagrams of solid-liquid equilibrium of binary systems of even saturated fatty alcohols from eight to eighteen atoms in the carbon chain by differential scanning calorimetry (DSC). This method was previously used by Rolemberg (2002) and Costa et al. (2007a, 2009a, 2009b, 2009c) for fatty acids and triacylglycerols systems. To complement the study were also captured images for some systems by optical microscope with temperature control. The liquidus line of the studied systems showed three different behaviors: one showed only the eutectic point, another the eutectic and peritectic points or neither eutectic nor peritectic point. For systems that had peritectic point, it could be observed in the microscopy images the recrystallization of the compositions that was investigated on the microscopy, even with the temperature increase. This behavior corroborates the existence of the metatetic reaction in these systems. Margules-2-suffix, Margules-3-suffix, NRTL, UNIFAC and UNIFAC-Dortmund models were applied to fit the experimental data. The best fit for the systems that exhibit peritectic and eutectic points were obtained through Margules and NRTL models. UNIFAC and UNIFAC-Dortmund models have showed high deviation compared to experimental data of the modeled systems
Mestrado
Mestre em Engenharia de Alimentos
Braga, Francisco Manuel de Carvalho. "Modelação do crescimento em altura e da relação diâmetro-altura de árvores jovens de Quercus suber." Master's thesis, UE/ISA, 2015. http://hdl.handle.net/10400.5/10789.
Full textThe objective of the present work was the modeling height growth in the regeneration stage and diameter growth in juvenile stage of the cork oak species. The data used were obtained from measurements performed on permanent plots installed in pure cork oak stands, located on the municipalities of Coruche, Estremoz, Ponte de Sôr, Sines, Évora, Idanha-a-Nova and Castelo Branco. The stands were characterized for soil type, climate and stand variables. Two tree-level functions were adjusted: one for total height growth in the regeneration stage and other for the diameter prediction. In both cases the functions selected were the ones presenting best performance through comparison of several fitting and prediction ability statistics (precision and bias). The rule established for the definition of the regeneration and juvenile phases applied in the SUBER model, based on a combination of values of total height and diameter at breast height, was discussed based on the values presented in the data set of the present work.
Antonio, Christian, and n/a. "Characterisation and optimisation of the variable frequency microwave technique and its application to microfabrication." Swinburne University of Technology, 2006. http://adt.lib.swin.edu.au./public/adt-VSWT20070220.122922.
Full textMiranda, João Vitor Meirelles de. "Leis de Escala em Cidades." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/100/100132/tde-21012016-134950/.
Full textThroughout history science has tried in many ways to sistematyze the knowledge about cities. Recent empirical discoveries started a new urban science, based on complex systems and data science( BATTY , 2013). One of the empirical foundation of this science is the scaling laws of diferent urban variables in relation to the urban population size. As a main hypothesis, it is sugested that as diferent as cities may be, there seems to be an evident scaling pattern between population size and socioeconomic production (superlinear) and infrastrufture variables (sublinear). A mean field model proposed by Bettencourt( BETTENCOURT , 2013) appears to present a plausible explanation for the origin of scaling laws in social interactions. However, this hypothesis still lacks more concluding empirical proof and further study of the model itself. This paper presents the results of an exploration of the scaling laws among Brazilian cities and a translation of Bettencourts model in a ABM framework. The scaling patterns of Brazilian cities appear to follow those found in other cities in the world with a certain robustness. Tax revenues and costs scaling were studied and Brazilian cities seem to optimize them as they grow. The model proved to be consistent with the facts observed empirically and indicated that very unequal city tend to have lower socioeconomic productions and greater areas of interactions and lower transportation costs tends to imply greater socioeconomic productions
Gumiere, Silvio José. "\"Modelagem do efeito da exclusão da chuva na dinâmica da água em solo da Floresta Nacional de Tapajós, Amazônia\"." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-11052007-091554/.
Full textEnvironmental instability caused by the combination of fire, deforestation and the ENSO phenomena (El Nino South Oscillation) can be the responsible for increases of dry periods in the Amazonian region. With the purpose of understanding the consequences that long dry periods can cause on the National Forest of Tapajós, a mathematical model that determines the water dynamics in soil and the hydrological balance was developed for a typical soil of the Amazonian region the Amazonianlatossol (Haplustox). The simulation were performed for the period from 1999 to 2003, using precipitation, evapotranspiration, soil moisture, retention curves and soil physical properties data obtained in the study area. The present study integrates the Dry-Forest Project of the LBA (Large Scale Biosphere-Atmosphere experiment in the Amazon) research group for the experiment of rainfall exclusion in the National Forest of Tapajos and concerns the hydrological modeling component of the project. The results showed that even with a decrease in the amount of water available to the Forest, significant changes in the hydrological balance of the forest did not occur, showing that the forest had probably adapted itself to survive to longer periods of drought
Strauss, Luisa Mariele. "Um modelo em dinâmica de sistemas para o ensino superior." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/24517.
Full textHigher education in Brazil has experienced a rapid expansion since the publication of the Directives and Bases Law (LDB) in 1996 and the pliability of the Government for the launching of new programs and educational institutions, mainly driven by the private sector. Despite this expansion, Brazil has not yet reached the aim expected in the Education National Plan: 30% of young people from 18 to 24 years old in higher education. Moreover, the demand for undergraduate programs presents signs of retraction, characterizing a system with fast initial growth followed by stagnation. This thesis proposes to understand the dynamics of this system by developing a model in System Dynamics, analyzing the undergraduate higher education. The model considers regulation, aims, demand, supply and especially the balance between public and private sectors. The methodology consists in the stages of problem definition, formulation of the dynamic hypothesis, development of the simulation model and in the validation and scenario testing. This step resulted in an analysis of alternative scenarios for the Brazilian undergraduate higher education. As a result, this thesis allows one to analyze the possible behavior of key variables in each scenario and to make observations on the variables that are not defined in the real system.
Barros, Leonardo Augusto de 1981. "Estudos de modelagem molecular visando a síntese de um polímero de impressão molecular para a determinação de fenitrotiona em tomate." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249416.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: Esse trabalho teve como objetivo principal sintetizar um polímero de impressão molecular (MIP) para ser empregado em processo de extração em fase sólida (SPE), visando a determinação de resíduos de fenitrotiona (FNT) em tomates. Os reagentes da síntese foram selecionados a partir de estudos de modelagem molecular, usando para tanto o programa computacional Gaussian 03. As energias eletrônicas de ligação para a interação entre o monômero funcional e a FNT, no vácuo e no solvente, foram calculadas através do método DFT, no nível B3LYP e conjunto de base 6-31G(d). Os reagentes de síntese foram: FNT (molde), ácido metacrílico (monômero funcional), etilenoglicol dimetacrilato (reagente de ligação cruzada), AIBN (iniciador radicalar) e tolueno (solvente porogênico). Também foi sintetizado um polímero não-impresso (NIP). Por meio de estudos de adsorção foi avaliado o meio de melhor reconhecimento molecular. Foram construídas as isotermas de adsorção para cada um dos polímeros impresso e não impresso e foi avaliada a seletividade do MIP frente a análogos da FNT. Os polímeros foram caracterizados por infravermelho com transformada de Fourier, ressonância magnética nuclear de C, microscopia de varredura eletrônica e porosimetria de sorção de nitrogênio (BET). O MIP foi empregado como fase estacionária em SPE. Foi desenvolvido e validado um método para a determinação de FNT em tomates, usando a cromatografia líquida de alta eficiência. A eficiência de extração foi de 96%. A faixa linear foi de 130 a 2000 ng g, com uma linearidade superior a 0,99. A precisão intra-ensaio e inter-ensaio foram inferiores a 7,0% e 8,1%, respectivamente (níveis de fortificação 250, 500 e 1000 ng g). A exatidão foi superior a 89% no nível de fortificação em torno do limite máximo de resíduo de 500 ng g
Abstract: This work aimed the synthesis of a molecularly imprinted polymer (MIP) to be employed in process of solid phase extraction (SPE), for the determination of residues of fenitrothion (FNT) in tomatoes. The synthesis reagents were selected from molecular modeling, using the Gaussian 03 software. The electronic binding energies for the interaction between the functional monomer and the FNT, in vacuum and in solvent, were calculated by the DFT method in B3LYP level and 6-31G(d) basis set. The reagents of the synthesis were: FNT (template), methacrylic acid (functional monomer), ethyleneglycol dimethacrylate (cross-linker), AIBN (initiator) and toluene (porogenic solvent). Also, was synthesized a non-imprinted polymer. Through batch rebinding studies were evaluated the medium of the best molecular recognition. The adsorption isotherms for each imprinted and non-imprinted polymer were constructed and the selectivity of the MIP in relation to FNT analogues evaluated. The polymers were characterized by Fourier transform infrared, C nuclear magnetic resonance, scanning electron microscopy and nitrogen sorption porosimetry (BET). The MIP was employed as stationary phase in SPE. A method for the determination of FNT in tomatoes was developed and validated, using high performance liquid chromatography. The extraction efficiency was 96%. The linear range was 130 to 2000 ng g, with a linearity greater than 0.99. The intra-day and inter-day precision were lower than 7.0% and 8.1%, respectively (fortification levels 250, 500 e 1000 ng g). The accuracy was higher than 89% for a concentration level around the maximum residue limit of 500 ng g
Mestrado
Quimica Analitica
Mestre em Química
Vicentin, Daniel Chieregato. "Estudo da dinâmica de evolução do HIV em seres humanos utilizando sistema de equações diferenciais ordinárias." Botucatu, 2019. http://hdl.handle.net/11449/181551.
Full textResumo: O objetivo desta dissertação é abordar aspectos qualitativos de sistemas de equações diferenciais ordinárias e sistemas contínuos suaves por partes aplicados à dinâmica do Vírus da Imunodeficiência Humana (HIV). Neste trabalho, apresentamos um modelo matemático que descreve a dinâmica do HIV no corpo humano e o analisamos através da matriz da próxima geração e teoria de estabilidade, com a finalidade de prever se a doença fica ou não controlada. Posteriormente, estudamos um sistema de equações diferenciais ordinárias usado para modelar a dinâmica do vírus para diferentes tipos de tratamentos. Tal modelo foi explorado qualitativamente de duas maneiras: por um sistema contínuo (pelo método de Korobeinikov) e por um descontínuo (pelas convenções de Filippov). Analisamos o comportamento dinâmico de terapias antirretrovirais, visando a diminuição das concentrações virais no sangue, de acordo com a análise da estabilidade realizada.
Abstract: The goal of this dissertation is to study qualitative aspects about systems of ordinary differential equations and piecewise smooth systems applied to the dynamic of Human Immunodeficiency Virus (HIV). In this work, we present a mathematical model that describes the dynamic of HIV in the human body and we analyze this model by next-generation matrix and stability theory in order to predict if the disease becomes stable, and thus stop virus transmission. In addition, we studied another system of ordinary differential equations that were proposed to model the HIV dynamics assuming different therapies. We have explored qualitatively the model by two distinct approaches: a continuous system (by Korobeinikov method) and a discontinuous system (by Filippov theory). Due to the stability analysis, it was possible to understand the dynamics of anti-retroviral therapies, which are responsible for decreasing the concentration of detectable HIV in blood.
Mestre
Awade, Marcelo. "Padrões de movimentação de uma espécie de ave em paisagens fragmentadas e seus efeitos para a conectividade funcional: uma abordagem hierárquica." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/41/41134/tde-11122009-135213/.
Full textHabitat fragmentation is one of the major human impacts on terrestrial ecosystems. This process highly affects the species movement pattern, implying in considerable alterations on the connectivity between the remaining habitat patches. Consequently, it interferes in the spatial distribution and in the population dynamics of species. In this dissertation, some aspects of the routine and dispersal movements of Pyriglena leucoptera, an endemic bird of the Atlantic rainforest, were studied. These two movement types act in distinct scales, affecting, differently, the parameter regulating the structure of the populations. Using the playback technique, we verified if the gap-crossing capacity of this species, by routine movements, is affected by gap width. From this relation, we obtained gap-crossing probabilities, which were used to parameterize functional connectivity indices (one binary and one probabilistic) based on graph theory. In a model selection approach, these two indices plus another structural one (i.e. patch area) were compared to establish which one is the best to predict P. leucopteras incidence in forest fragments. About the dispersal movements, we done translocation and telemetry experiments to investigate if the species dispersal ability in fragmented landscapes is affected by the distance between forest patches, and to verify if there are sexual differences in this effect. The results showed that distance between forest patches limits both the routine movements and the dispersal one to this species. In the routine movements scale, we verified that patches are completely isolated when the gap width is higher than 45 m. The species incidence was better described by the probabilistic connectivity index (PCS), evincing that it is essential to consider connectivity to understand the spatial distribution of P. leucoptera, and this attribute must be viewed in its probabilistic form. Furthermore, dispersal is female-biased, since females are more prone to emigrate and were more efficient in their movement in the matrix. We discussed the consequences of this sex-bias, highlighting that, in severely fragmented landscapes, the colonization probability of empty patches is decreased and the genetic flux between populations should be imperiled. Thus, to comprehend the effects of habitat connectivity on species survival in fragmented landscapes, both movement types must be considered. Finally, we suggested a hierarchically structured population model in order to integrate the two movement type information in one conceptual framework. This model has a great potential to be used in environmental planning and management.
Ferrari, Luiz Carlos Kauffman Marasco. "Modelagem tridimensional de fluxo de águas subterrâneas em um aqüífero livre e raso: aplicação no Parque Ecológico do Tietê - São Paulo." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/44/44133/tde-29062007-091519/.
Full textThe importance of studying unconfined and shallow aquifers is verified when taking into account that these aquifers are highly vulnerable to contamination and that they are often located under heavily populated regions. A detailed three-dimensional and transient model, which represents the groundwater flow in an area of an unconfined and shallow aquifer at the Parque Ecológico do Tietê, in the Municipality of São Paulo, Brazil, was created and calibrated with the objective of enhancing the comprehension of the dynamics of the groundwater flow in the saturated zone of these formations. This model was based on hydraulic head data of 81 monitoring wells, which were installed in an area of 320 m2 and measured on a daily basis, on daily values of precipitation occurring in the area and 75 determinations of hydraulic conductivities. The model was created and run using the software Visual MODFLOW and calibrated using the software PEST, based on a non-linear regression method. The results generated by this method for an event of rapid recharge indicate that the distribution of the horizontal hydraulic conductivities and by the specific yield of the upper layers of the formation, but it is mostly disconnected from the intensity and temporal distribution of the local recharge, that only influences the shallowest levels of the formation. Furthermore, the extremely dynamic character of the flow can be verified, which responds rapidly to the regional recharge event, presenting significant changes of intensity and direction within only a few days. These results, which were only observable through a very detailed model such as the one produced and presented in this study, suggest that commonly employed evaluation strategies may not be capable of evaluating this kind of aquifer in a satisfactory way.
Andrade, Gabriel Ramatis Pugliese. "Gênese de argilominerais em solos de manguezais brasileiros." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-30042015-144453/.
Full textClay minerals are ubiquitous components in < 2 μm size fraction of soils, having an important role in the control of geochemical processes and soil genesis. Despite of the general characterizations performed in Brazilian mangroves soils there is a lack of a detailed crystal chemical study able to evidence mechanisms of formation/transformation of such minerals. This study aims (by two different comparative works) to enhance the crystal chemical characterization of mineral phases in the 2-0,2 μm and < 0,2 μm size fractions of mangrove soils, suggesting the existence of mineral transformation involving clay phases and comprehending what environmental settings are related to these transformations. This characterization is based on XRD modelling of oriented patterns, peak fitting of 060 peaks in randomly XRD patterns, Mössbauer spectroscopy, thermal analysis, chemical analysis of soil pore water and geochemical modelling of inorganic soluble compounds. The results, which are described in chapters 2 and 3 indicate a sequence of mineral transformations, via mixed-layered clays, which may have important consequences for the comprehension of soil genesis processes involving clay minerals, their role in the biogeochemical cycles of structural elements of clays and a straight relationship with biotic components of mangrove ecosystem.
Boscolo, Danilo. "Influência da estrutura da paisagem sobre a persistência de três espécies de aves em paisagens fragmentadas da Mata Atlântica." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/41/41134/tde-13022008-180423/.
Full textHabitat loss and fragmentation are currently the most important threats to the conservation of biodiversity. These processes may generate patchy landscapes where several species are forced to survive in small and isolated populations, which are very susceptible to local extinctions. According to the metapopulation theory, if local extinctions in specific patches can be compensated by re-colonization from surrounding populations, a species can persist despite fragmentation. Extinctions and re-colonizations are processes that depend directly on landscape structure. Small patches with low habitat quality have increased extinction probabilities, while poorly connected landscapes with high resistance to the dispersal of individuals have decreased re-colonization rates. Spatially explicit population viability models (SEPVM) allow analyses of the influence of different types of landscapes on the persistence of species, contributing to conservation strategies decision making. The objective of the current thesis was to identify the factors which affect the persistence of three forest bird species endemic to the Atlantic forest (Chiroxiphia caudata, Xiphorhynchus fuscus and Pyriglena leucoptera) through a SEPVM. Four different fragmented landscapes of the Atlantic plateau of São Paulo were chosen for this study. The playback technique was used to assess the incidence of the birds inside 80 forest fragments in these landscapes. These data were used to derive logistic incidence models to estimate their occurrence probabilities according to the cover and spatial pattern of the surrounding landscape. Furthermore, the movement pattern of the birds between forest fragments was inferred from playback experiments which induced birds to overcome the matrix, and through the translocation of individual birds which were followed by radio-telemetry. The incidence models indicated that the occurrence probability of the birds in places of fragmented habitat depends in large scale on the spatial distribution of forest remnants, being higher where patch isolation is low. This effect becomes even more important in places where habitat patches are not big enough to provided the birds with sufficient resources, forcing them to search for it in nearby forests, which shall not be further away than the birds\' aptitude to move through the landscape. Their ability to overcome the inter-habitat matrix, reaching close by forests, was confirmed by the experiments on individuals\' movements. The studied species are able to move between nearby forest patches, being even able to use habitat corridors or isolated trees to ease their passage through the landscape. These results indicate that the territories of the studied species can include isolated patches which are connected by birds\' movement. Also, the minimum conditions to the establishment of these territories in terms of amount and aggregation of forests varies according to the species. These results, added to bibliographical information on the studied birds\' biology, were used to guide the development of an ecologically scaled SEPVM, in which the landscape cells were defined as potential bird territories. This viability model was greatly useful to assess the effects of landscape structural changes on the persistence of small territorial birds\' populations. Simulations using both artificial and real landscapes indicated that, in a wide landscape scale, the persistence of these species is largely subjected to the amount of territories the landscape can bear, but not to its aggregation. Nevertheless, increases of forest density lead to a higher amount of possible territories, positively affecting the persistence of the species. The SEPVM developed for the current thesis allowed the reconciliation of a structural analysis of the landscape to dynamical population modeling, what is considered as a top priority research subject in landscape ecology.
Pereira, Felipe Augusto Cardoso. "Bolhas em fluidos: Uma abordagem com a teoria do caos." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-23092014-154749/.
Full textWe studied the bubble formation dynamics in viscous fluids. We developed new experimental techniques to provide a better understanding of the system with one bubbling nozzle on the bottom of a cylinder filled with a water and glycerol solution. In this system, we control the air flow with a mass flowme- ter and a solenoid valve. We have measured simultaneously: the time between successive bubbles, using a laser focused in a photo-diode that has his light scattered when one bubble passes between them; the pressure waves that the bubbling causes in the air injecting system using microphones placed between the solenoid valve and the nozzle; and the geometry of the growing bubbles, through the analysis of the images collected by a high speed camera. The re- sults from this system motivated us to make a model for the bubbles formation dynamics that describes the period-adding route observed in the experiment and is based on first principles. We also investigated a new experimental system, that has two bubbling nozzles inside the same cylinder. We used the same experimetal techniques developed to the one nozzle experiment. We identified that the bubbling on the nozzles synchronizes due the coupling introduced by the liquid circulation, as the air injecting systems are independent. We studied the synchronization by constructing bifurcation diagrams and parameter spaces that show the syn- chronized regions. We also adapted the one nozzle bubbling model to decribe this system. We discovered that the interaction between the two bubble forma- tion dynamics is stronger when we increase the liquid height.
Mello, Jéssica Adriane de. "A modelagem matemática na perspectiva sócio-crítica : uma experiência em um curso de costureiras." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/148201.
Full textThis dissertation shows the development of a research, followed by experimentation, in the Seamstress Course which is part of Mulheres Mil - PRONATEC Program offered by Sul-rio-grandense Federal Institute about Financial Mathematics using mathematical modeling tasks. The aim of this study is to investigate how it is possible to awake the students‟ critical sense, seeking to find the importance of Mathematics in the society using tasks that allow to think and interfere in the reality where they live. The theoretical frameworks are Critical Mathematic Education according to Skovsmose (2012) and the Mathematical Modelling by Barbosa‟s Socio-critical perspective (2001). To analyze the students‟ contribuitions/reflections, we were based on the Content Analysis, according to the model of Bardin (2006). The analysis of theses contribuitions shows indicatives of the students‟ reflections and reactions aligned with the Critical Mathematics Education‟s interest.
Kucharska, Magdalena, and Jolanta Pielaszkiewicz. "NIG distribution in modelling stock returns with assumption about stochastic volatility : Estimation of parameters and application to VaR and ETL." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-2874.
Full textWe model Normal Inverse Gaussian distributed log-returns with the assumption of stochastic volatility. We consider different methods of parametrization of returns and following the paper of Lindberg, [21] we
assume that the volatility is a linear function of the number of trades. In addition to the Lindberg’s paper, we suggest daily stock volumes and amounts as alternative measures of the volatility.
As an application of the models, we perform Value-at-Risk and Expected Tail Loss predictions by the Lindberg’s volatility model and by our own suggested model. These applications are new and not described in the
literature. For better understanding of our caluclations, programmes and simulations, basic informations and properties about the Normal Inverse Gaussian and Inverse Gaussian distributions are provided. Practical applications of the models are implemented on the Nasdaq-OMX, where we have calculated Value-at-Risk and Expected Tail Loss
for the Ericsson B stock data during the period 1999 to 2004.
Matamoros, Efrain Pantaleón. "Modelo de desgaste oxidativo baseado em parâmetros termodinâmicos." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/3/3132/tde-30042004-180341/.
Full textDuring sliding wear, heat generated friction occurs, which favors oxidation occurrence on the contacting surfaces of metallic materials. The oxidation phenomenon can result in wear rate attenuation due to transitions in the contact feature from metal-metal to either metal-oxide or oxide-oxide. This work aimed to develop a theoretical modeling on oxidational wear. In the obtained model, both thermodynamic and tribological parameters were used, such as Gibbs energy, load, actual area of contact, velocity and contact temperature. In order to obtain experimental data for the model assessment, usual pin-on-disk tests were conducted under some load and velocity conditions. Relations among the variables, such as contact temperature, load, velocity and physical-chemical properties of the materials, were attained. The tests were performed under continuous rising on load. Intervals from 20 to 120 N, 20 to 80 N and 20 to 40 N were tested. The pin material was made of quenched and tempered M2 tool steel and the disks were of austempered AISI 1045 steel with bainitic microstructure. Surface characterization was carried out before and after the tests, through optical and scanning electronic microscopes. Analyzing the results obtained from the model and from the experimental tests, it was possible to conclude that the wear phenomenon is related to the contact energy, which depends on the physical-chemical conditions of the surfaces, the environment and the mechanical loading the surfaces undergo. The material properties, which do also influence the wear rate, were taken into consideration in the model as the Gibbs energy of the materials.
Vianna, Murilo dos Santos. "Functional, structural and agrohydrological sugarcane crop modelling: towards a simulation platform for Brazilian farming systems." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-01082018-150704/.
Full textA cultura da cana-de-açúcar é a principal fonte de açúcar e a segunda maior fonte de biocombustíveis do mundo. O Brasil é o maior produtor mundial desde a década de 80 e atualmente representa metade da produção mundial, enquanto que ao mesmo tempo o etanol e a biomassa correspondem a mais de 15% da fonte de energia do país. Contudo, a produtividade comercial da cana-de-açúcar brasileira atingiu um limiar de cerca de 75 t ha-1 e para atender à crescente demanda de açúcar e etanol, a cultura expandiu-se fortemente para a região centro-oeste, onde a irrigação é obrigatória para manter os níveis de produção e diminuir riscos de quebra de safra. Para dar suporte a tomada de decisão e avanço científico sobre onde e como a cultura deve se expandir e/ou aumentar a produtividade, é necessária uma visão heurística do sistema agrícola brasileiro que pode ser traduzida matematicamente para um modelo de cultura. Desta forma, os efeitos do manejo e tipo de solo, variabilidade climática e fatores econômicos na produtividade de culturas agrícolas podem ser avaliados quantitativamente por meio de modelos de culturas baseados em processos (MBP). No entanto, em contraste a outras culturas, a cana-de-açúcar possui apenas dois MBPs disponíveis para usuários finais (DSSAT-CANEGRO e APSIM-Sugar) que requerem calibração e parametrização para melhor representar o sistema agrícola de cana-de-açúcar do Brasil. Portanto, este estudo teve como objetivo desenvolver, calibrar e avaliar diferentes abordagens de modelagem de culturas voltadas a produção de cana-de-açúcar no Brasil, para servir como ferramenta de tomada de decisão para o setor público e privado, auxilio no manejo da água e avaliação dos impactos nas mudanças climáticas. Portanto, uma nova versão do modelo baseado em processo de cana-de-açúcar (SAMUCA) foi desenvolvida para operar a nível de fitômeros, incluindo os efeitos no crescimento e desenvolvimento da cana com base na cobertura da palha no solo, competição por luz no processo de perfilhamento e acúmulo de sacarose com base nas relações fonte-dreno. O modelo foi incorporado em uma plataforma modular dedicada a simular o sistema solo-planta-atmosfera e manejo do sistema agrícola. Além disso, a versão anterior do SAMUCA também foi reestruturada e acoplada à plataforma agro-hidrológica SWAP (\"Soil, Water, Atmosphere and Plant\") com objetivo de aprimorar as simulações de balanço hídrico no solo e efeito no crescimento da cana-de-açúcar. Por fim, um Modelo Funcional-Estrutural de Plantas (MFEP) para a cana-de-açúcar foi desenvolvido integrando os principais componentes da cultura a nível de órgãos (fitômeros) com base em uma abordagem de fonte-dreno e um modelo robusto de radiação que foram introduzidos em uma plataforma de modelagem tridimensional (GroIMP). As três abordagens foram avaliadas e seu desempenho foi determinado com base em condições experimentais para diferentes regiões brasileiras. O desempenho da nova versão do modelo SAMUCA em experimento de longo prazo e em diferentes condições brasileiras foi satisfatório e os índices de concordância foram próximos de outros modelos de cana-de-açúcar amplamente utilizados (CANEGRO e APSIM-Sugar). Além disso, a plataforma de simulação de culturas modulada pode ser usada para hospedar mais modelos de culturas e integrar novas características do sistema de cultivo brasileiro. O acoplamento do modelo SWAP-SAMUCA foi realizado e apesar não apresentar melhorias expressivas no desempenho do modelo em simular os componentes da cultura (com erro médio quadrático [RMSE] 6% menor), a habilidade do modelo SWAP-SAMUCA em simular o teor de água no solo mostrou-se consideravelmente superior em comparação ao modelo original (RMSE 32% menor). O MFEP para cana-de-açúcar foi capaz de simular o desenvolvimento do dossel, o processo de perfilhamento e o acúmulo de sacarose ao nível de órgãos e planta de forma satisfatória. Além de sua capacidade em simular com precisão a interceptação da radiação por cada estrutura do dossel, podendo auxiliar na compreensão do processo de competição intraespecífica entre perfilhos, a estrutura do MFEP da cana-de-açúcar também pode ser usada no apoio à pesquisa focando os mecanismos de acúmulo de sacarose e translocação de açúcares bem como em estudos de consórcio em cana-de-açúcar, como têm sido realizado com sucesso para outras culturas nos últimos anos.
Kucharska, Magdalena, and Jolanta Maria Pielaszkiewicz. "NIG distribution in modelling stock returns with assumption about stochastic volatility : Estimation of parameters and application to VaR and ETL." Thesis, Halmstad University, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-58180.
Full textSantos, Clayton Eduardo dos. "Modelagem computacional de estruturas anatômicas em 3D e simulação de suas imagens radiográficas." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/18/18133/tde-15102008-141521/.
Full textThe conventional methods of quality control applied to radio diagnosis are the best way to have assured good quality of the produced images. Due the amount of variables to consider, the study of particular issues of the process of formation of radiological images requires complementary computational tools. However, the computational voxel based phantoms are not suitable to represent the morphometrical variations, intended for test simulations with image based diagnosis. This work developed a new type of computational phantom, based on 3D modelling. It has the same advantages of the conventional ones, without some of their restrictions. The modeling tool employed, Blender, is available on internet for free download. The project uses the technique called box modeling, which consists in the deformation of a primitive form (a cube, in this case) until it presents a similar form to that it is wanted to model. In order to achieve it, some images, obtained from anatomy atlas and a skeleton pictures obtained from University of Mogi das Cruzes, were used as reference. Were built models from skeletal system, internal organs and external human body anatomy. The applied methodology allowed model´s parameter settings on the modelling tool. This option was presented by means of intestine format variation and increase of adipose tissue on the mesh that represents skin. The simulation of radiological images was done by means of x-ray mass attenuation coefficients, bones and tissues and models with diferent physical characteristics. This flexibility allows the analysis and forecasting of the influences that morphometrical differences of individual implies on images, revealing an important tool that complements the conventional quality control tools.