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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Evaluation Of Performance And Optimum Valve Settings For Pressure Management Using Forecasted Daily Demand Curves By Artificial Neural Networks

Yildiz, Evren 01 August 2011 (has links) (PDF)
For the appropriate operation and correct short term planning, daily demand curve (DDC) of municipal water distribution networks should be forecasted beforehand. For that purpose, artificial neural networks (ANN) is used as a new method. The proposed approach employs already recorded DDCs extracted from the database of ASKI (Ankara Water Authority) SCADA center and related independent parameters such as temperature and relative humidity obtained from DMI (State Meteorological Institute). In this study, a computer model was developed in order to forecast hourly DDCs using Matlab and related modules. Parameters that affect the consumption of the water were determined as temperature, relative humidity, human behavior (weekend or workday) and season. Randomly selected days were taken into account for performance of the ANN model. Forecasted DDC values were compared with recorded data and consequently the model gives relatively satisfactory results, an average of 75% match according to R2 values for Ankara N8-3 network. Same architecture was applied for Antalya network give better results, average of 85%. For planning purposes / total volume and peak water consumption values for the selected recorded days, the day before recorded days, ANN forecasted days and seasonal average was compared and seasonal average gave relatively better results. Using the forecasted DDC, (i) performance analysis of the pressure zone and (ii) optimum valve setting evaluation for pressure management were realized. The results of the study may help water utilities for short term planning of a water distribution network, rehabilitation of elements, taking counter measures and setting the valve openings for minimizing leakage and optimizing customer conformity of the distribution network.
102

Evaluation Of Performance And Optimum Valve Settings For Pressure Management Using Forecasted Daily Demand Curves By Artificial Neural Networks

Yildiz, Evren 01 August 2011 (has links) (PDF)
For the appropriate operation and correct short term planning, daily demand curve (DDC) of municipal water distribution networks should be forecasted beforehand. For that purpose, artificial neural networks (ANN) is used as a new method. The proposed approach employs already recorded DDCs extracted from the database of ASKI (Ankara Water Authority) SCADA center and related independent parameters such as temperature and relative humidity obtained from DMI (State Meteorological Institute). In this study, a computer model was developed in order to forecast hourly DDCs using Matlab and related modules. Parameters that affect the consumption of the water were determined as temperature, relative humidity, human behavior (weekend or workday) and season. Randomly selected days were taken into account for performance of the ANN model. Forecasted DDC values were compared with recorded data and consequently the model gives relatively satisfactory results, an average of 75% match according to R2 values for Ankara N8-3 network. Same architecture was applied for Antalya network give better results, average of 85%. For planning purposes / total volume and peak water consumption values for the selected recorded days, the day before recorded days, ANN forecasted days and seasonal average was compared and seasonal average gave relatively better results. Using the forecasted DDC, (i) performance analysis of the pressure zone and (ii) optimum valve setting evaluation for pressure management were realized. The results of the study may help water utilities for short term planning of a water distribution network, rehabilitation of elements, taking counter measures and setting the valve openings for minimizing leakage and optimizing customer conformity of the distribution network.
103

Roman intervention in the Punic west: a study of its probable causes

Fort, Thomas Allen January 1978 (has links)
No description available.
104

Estudo do processo de estampagem para materiais alternativos na fabricação de um componente para a indústria de máquinas agrícolas

Bau, Atilano Roberto January 2015 (has links)
No presente trabalho, a conformabilidade do aço inoxinoxidável AISI 201 foi comparada com o aço inoxidável AISI 304. O aço inoxidável AISI 201 é uma liga baixo níquel ligado com manganês e nitrogênio. Nesse estudo a conformabilidade dos dois materiais foi examinada por meio de ensaios tecnológicos como ensaio de tração, determinação da curva de escoamento, determinação do índice de anisotropia, ensaio Erichsen, dureza, composição química, simulação computacional do processo de estampagem e estampagem dos blanks. O aço inoxidável AISI 201 possui propriedades como limite de escoamento e tensão de ruptura superior as do inoxidável AISI 304. Os dois aços possuem uma similaridade na anisotropia. A máxima altura alcançada no momento da fratura pelo ensaio Erichsen também é semelhante para os dois materiais. O aço inox AISI 201 apresenta uma dureza maior que o inoxidável AISI 304. Na composição química os dois aços apresentam elementos fora do especificado, caracterizando um problema de qualidade na fabricação desses aços. A simulação computacional do processo de estampagem apresentou uma redução de espessura na região mais critica, sem comprometer a estampagem do componente. Uma vez estampadas, obteve-se peças sem indícios de trincas, conforme previsto pela simulação computacional. Os resultados desse trabalho sugerem a possibilidade de utilização do aço inoxidável AISI 201 como opção para substituição ao inoxidável AISI 304, tendo uma observação a ser feita quanto aos cuidados na qualidade durante a fabricação do aço para que atenda os padrões exigidos. / In this study, the formability of stainless steel AISI 201 was compared to stainless steel AISI 304 stainless steel AISI 201 is a low alloy nickel alloyed with manganese and nitrogen. In this study, the formability of the two materials was examined by means of technological tests such as tensile test, determination of the flow curve, determining the anisotropy index, Erichsen test, hardness, chemical composition, computer simulation of the stamping process and stamping of the blanks. Stainless steel AISI 201 has properties such as yield strength and higher breakdown voltage of the stainless steel AISI 304. The two steels have a similarity in anisotropy. The maximum height reached at the time of fracture by Erichsen test is also similar for the two materials. Stainless steel AISI 201 has a hardness greater than the stainless steel AISI 304. In chemistry the two steels have elements outside the specified, featuring a quality problem in manufacturing these steels. A computer simulation of the printing process showed a reduction in thickness in the most critical region, without compromising the component stamping. Once stamped, gave no broken pieces of evidence as provided by the computer simulation. The findings suggest the possibility of use of stainless steel AISI 201 as an option to replace the stainless steel AISI 304, with a point to be made about the care as during the manufacture of steel that meets the required standards.
105

Estudo do processo de estampagem para materiais alternativos na fabricação de um componente para a indústria de máquinas agrícolas

Bau, Atilano Roberto January 2015 (has links)
No presente trabalho, a conformabilidade do aço inoxinoxidável AISI 201 foi comparada com o aço inoxidável AISI 304. O aço inoxidável AISI 201 é uma liga baixo níquel ligado com manganês e nitrogênio. Nesse estudo a conformabilidade dos dois materiais foi examinada por meio de ensaios tecnológicos como ensaio de tração, determinação da curva de escoamento, determinação do índice de anisotropia, ensaio Erichsen, dureza, composição química, simulação computacional do processo de estampagem e estampagem dos blanks. O aço inoxidável AISI 201 possui propriedades como limite de escoamento e tensão de ruptura superior as do inoxidável AISI 304. Os dois aços possuem uma similaridade na anisotropia. A máxima altura alcançada no momento da fratura pelo ensaio Erichsen também é semelhante para os dois materiais. O aço inox AISI 201 apresenta uma dureza maior que o inoxidável AISI 304. Na composição química os dois aços apresentam elementos fora do especificado, caracterizando um problema de qualidade na fabricação desses aços. A simulação computacional do processo de estampagem apresentou uma redução de espessura na região mais critica, sem comprometer a estampagem do componente. Uma vez estampadas, obteve-se peças sem indícios de trincas, conforme previsto pela simulação computacional. Os resultados desse trabalho sugerem a possibilidade de utilização do aço inoxidável AISI 201 como opção para substituição ao inoxidável AISI 304, tendo uma observação a ser feita quanto aos cuidados na qualidade durante a fabricação do aço para que atenda os padrões exigidos. / In this study, the formability of stainless steel AISI 201 was compared to stainless steel AISI 304 stainless steel AISI 201 is a low alloy nickel alloyed with manganese and nitrogen. In this study, the formability of the two materials was examined by means of technological tests such as tensile test, determination of the flow curve, determining the anisotropy index, Erichsen test, hardness, chemical composition, computer simulation of the stamping process and stamping of the blanks. Stainless steel AISI 201 has properties such as yield strength and higher breakdown voltage of the stainless steel AISI 304. The two steels have a similarity in anisotropy. The maximum height reached at the time of fracture by Erichsen test is also similar for the two materials. Stainless steel AISI 201 has a hardness greater than the stainless steel AISI 304. In chemistry the two steels have elements outside the specified, featuring a quality problem in manufacturing these steels. A computer simulation of the printing process showed a reduction in thickness in the most critical region, without compromising the component stamping. Once stamped, gave no broken pieces of evidence as provided by the computer simulation. The findings suggest the possibility of use of stainless steel AISI 201 as an option to replace the stainless steel AISI 304, with a point to be made about the care as during the manufacture of steel that meets the required standards.
106

Estudo do processo de estampagem para materiais alternativos na fabricação de um componente para a indústria de máquinas agrícolas

Bau, Atilano Roberto January 2015 (has links)
No presente trabalho, a conformabilidade do aço inoxinoxidável AISI 201 foi comparada com o aço inoxidável AISI 304. O aço inoxidável AISI 201 é uma liga baixo níquel ligado com manganês e nitrogênio. Nesse estudo a conformabilidade dos dois materiais foi examinada por meio de ensaios tecnológicos como ensaio de tração, determinação da curva de escoamento, determinação do índice de anisotropia, ensaio Erichsen, dureza, composição química, simulação computacional do processo de estampagem e estampagem dos blanks. O aço inoxidável AISI 201 possui propriedades como limite de escoamento e tensão de ruptura superior as do inoxidável AISI 304. Os dois aços possuem uma similaridade na anisotropia. A máxima altura alcançada no momento da fratura pelo ensaio Erichsen também é semelhante para os dois materiais. O aço inox AISI 201 apresenta uma dureza maior que o inoxidável AISI 304. Na composição química os dois aços apresentam elementos fora do especificado, caracterizando um problema de qualidade na fabricação desses aços. A simulação computacional do processo de estampagem apresentou uma redução de espessura na região mais critica, sem comprometer a estampagem do componente. Uma vez estampadas, obteve-se peças sem indícios de trincas, conforme previsto pela simulação computacional. Os resultados desse trabalho sugerem a possibilidade de utilização do aço inoxidável AISI 201 como opção para substituição ao inoxidável AISI 304, tendo uma observação a ser feita quanto aos cuidados na qualidade durante a fabricação do aço para que atenda os padrões exigidos. / In this study, the formability of stainless steel AISI 201 was compared to stainless steel AISI 304 stainless steel AISI 201 is a low alloy nickel alloyed with manganese and nitrogen. In this study, the formability of the two materials was examined by means of technological tests such as tensile test, determination of the flow curve, determining the anisotropy index, Erichsen test, hardness, chemical composition, computer simulation of the stamping process and stamping of the blanks. Stainless steel AISI 201 has properties such as yield strength and higher breakdown voltage of the stainless steel AISI 304. The two steels have a similarity in anisotropy. The maximum height reached at the time of fracture by Erichsen test is also similar for the two materials. Stainless steel AISI 201 has a hardness greater than the stainless steel AISI 304. In chemistry the two steels have elements outside the specified, featuring a quality problem in manufacturing these steels. A computer simulation of the printing process showed a reduction in thickness in the most critical region, without compromising the component stamping. Once stamped, gave no broken pieces of evidence as provided by the computer simulation. The findings suggest the possibility of use of stainless steel AISI 201 as an option to replace the stainless steel AISI 304, with a point to be made about the care as during the manufacture of steel that meets the required standards.
107

Le travail domestique au Brésil : une étude à la lumière de la Convention n° 189 et de la Recommandation n° 201 de l’OIT

Marchandeau Conde, Carla 12 1900 (has links)
Le travail domestique est une des formes d’emploi les plus anciennes au monde. Au Brésil, ce type de service tire son origine de l’esclavage, technique d’exploitation économique qui a marqué l’histoire du pays durant environ 400 (quatre cents) ans. Encore au XXIème siècle, le travail domestique est sous-évalué et peine à être reconnu comme un vrai travail. La législation nationale a progressé au point de reconnaitre aux employés de maison les mêmes droits dont jouissent les autres salariés (amendement constitutionnel, 2013). Le droit international du travail joue un rôle crucial dans l’encadrement de la situation des travailleuses domestiques au monde. La Convention concernant le travail décent pour les travailleurs et travailleuses domestiques (n° 189) et la Recommandation n° 201 l’accompagnant de l’Organisation internationale du travail (OIT) occupent une place importante dans la promotion du travail décent aux travailleurs domestiques. Malgré l’existence de normes – nationales et internationales – importantes, la problématique de la condition de travail et de vie des travailleuses domestiques au Brésil va au-delà de la législation, impliquant la notion culturelle de dévalorisation du travail domestique, cette même conception qui associe le travail à domicile à l’esclavage. / Domestic work is one of the oldest forms of employment in the world. In Brazil, this type of service has its roots in slavery, an economic exploitation technique that has marked the history of the country for about 400 (four hundred) years. Even in the XXI century, domestic work is undervalued and barely recognized as a real job. National legislation has progressed to the point of recognizing domestic workers the same rights enjoyed by other employees (Constitutional Amendment, 2013). The International labor law has a crucial importance in the supervision of the situation of domestic workers in the world. The Convention Concerning Decent Work for Domestic Workers (n° 189) and the Recommendation n° 201 of the International Labour Organisation (ILO) play a key role in promoting decent work for domestic workers. Despite the existence of relevant national and international standards, the matter of working and living conditions of domestic workers in Brazil goes beyond the legislation because it involves the notion of cultural devaluation of domestic work, the same idea that associates home work to slavery.
108

Scientific Workflows for Hadoop

Bux, Marc Nicolas 07 August 2018 (has links)
Scientific Workflows bieten flexible Möglichkeiten für die Modellierung und den Austausch komplexer Arbeitsabläufe zur Analyse wissenschaftlicher Daten. In den letzten Jahrzehnten sind verschiedene Systeme entstanden, die den Entwurf, die Ausführung und die Verwaltung solcher Scientific Workflows unterstützen und erleichtern. In mehreren wissenschaftlichen Disziplinen wachsen die Mengen zu verarbeitender Daten inzwischen jedoch schneller als die Rechenleistung und der Speicherplatz verfügbarer Rechner. Parallelisierung und verteilte Ausführung werden häufig angewendet, um mit wachsenden Datenmengen Schritt zu halten. Allerdings sind die durch verteilte Infrastrukturen bereitgestellten Ressourcen häufig heterogen, instabil und unzuverlässig. Um die Skalierbarkeit solcher Infrastrukturen nutzen zu können, müssen daher mehrere Anforderungen erfüllt sein: Scientific Workflows müssen parallelisiert werden. Simulations-Frameworks zur Evaluation von Planungsalgorithmen müssen die Instabilität verteilter Infrastrukturen berücksichtigen. Adaptive Planungsalgorithmen müssen eingesetzt werden, um die Nutzung instabiler Ressourcen zu optimieren. Hadoop oder ähnliche Systeme zur skalierbaren Verwaltung verteilter Ressourcen müssen verwendet werden. Diese Dissertation präsentiert neue Lösungen für diese Anforderungen. Zunächst stellen wir DynamicCloudSim vor, ein Simulations-Framework für Cloud-Infrastrukturen, welches verschiedene Aspekte der Variabilität adäquat modelliert. Im Anschluss beschreiben wir ERA, einen adaptiven Planungsalgorithmus, der die Ausführungszeit eines Scientific Workflows optimiert, indem er Heterogenität ausnutzt, kritische Teile des Workflows repliziert und sich an Veränderungen in der Infrastruktur anpasst. Schließlich präsentieren wir Hi-WAY, eine Ausführungsumgebung die ERA integriert und die hochgradig skalierbare Ausführungen in verschiedenen Sprachen beschriebener Scientific Workflows auf Hadoop ermöglicht. / Scientific workflows provide a means to model, execute, and exchange the increasingly complex analysis pipelines necessary for today's data-driven science. Over the last decades, scientific workflow management systems have emerged to facilitate the design, execution, and monitoring of such workflows. At the same time, the amounts of data generated in various areas of science outpaced hardware advancements. Parallelization and distributed execution are generally proposed to deal with increasing amounts of data. However, the resources provided by distributed infrastructures are subject to heterogeneity, dynamic performance changes at runtime, and occasional failures. To leverage the scalability provided by these infrastructures despite the observed aspects of performance variability, workflow management systems have to progress: Parallelization potentials in scientific workflows have to be detected and exploited. Simulation frameworks, which are commonly employed for the evaluation of scheduling mechanisms, have to consider the instability encountered on the infrastructures they emulate. Adaptive scheduling mechanisms have to be employed to optimize resource utilization in the face of instability. State-of-the-art systems for scalable distributed resource management and storage, such as Apache Hadoop, have to be supported. This dissertation presents novel solutions for these aspirations. First, we introduce DynamicCloudSim, a cloud computing simulation framework that is able to adequately model the various aspects of variability encountered in computational clouds. Secondly, we outline ERA, an adaptive scheduling policy that optimizes workflow makespan by exploiting heterogeneity, replicating bottlenecks in workflow execution, and adapting to changes in the underlying infrastructure. Finally, we present Hi-WAY, an execution engine that integrates ERA and enables the highly scalable execution of scientific workflows written in a number of languages on Hadoop.
109

Estudo das impurezas radioativas gama emissoras presentes nos radiofármacos produzidos no IPEN-CNEN/SP / Study of the radioactive impurities gamma emitters present in the radiopharmaceutical solutions produced at IPEN-CNEN/SP

ALMEIDA, JAMILLE da S. 22 November 2017 (has links)
Submitted by Pedro Silva Filho (pfsilva@ipen.br) on 2017-11-22T17:07:51Z No. of bitstreams: 0 / Made available in DSpace on 2017-11-22T17:07:51Z (GMT). No. of bitstreams: 0 / Este trabalho tem como objetivo investigar a concentração de impurezas radioativas gama emissoras presentes nas soluções dos radiofármacos produzidos no Instituto de Pesquisas Energéticas e Nucleares - IPEN em São Paulo. Para que este radiofármaco possa ser utilizado adequadamente, sua qualidade deve ser avaliada de acordo com os procedimentos estabelecidos de acordo com os \"Requisitos Gerais para a Competência de Laboratórios de Teste e Calibração\", ISO / IEC 17025: 2005 e pelas \"Boas Práticas de Fabricação\" (BPF), controladas pela ANVISA (Agência Nacional de Vigilância Sanitária), no Brasil. Para determinar a atividade, dos radiofármacos das impurezas gama emissoras, foi utilizado um espectrômetro gama de alta resolução em duas distâncias fonte-detector; uma de 18 cm e outra de 1,7 cm. Para a distância de 18 cm, o espectrômetro HPGe foi calibrado com energias gama entre 81 kev e 1408 kev, medindo ampolas seladas de 60Co, 133Ba, 137Cs e 152Eu, padronizadas no Laboratório de Metrologia Nuclear (LMN) do IPEN. Para impurezas com baixas atividades, utilizou a distância fontedetector de 1,7 cm. A esta distância, o efeito soma em cascata é muito elevado, tornando difícil a medição das ampolas de calibração padrão, com isso, a curva de eficiência do espectrômetro foi obtida por um código de simulação de Monte Carlo, desenvolvido no IPEN. Neste código, todos os detalhes do sistema de detecção são modelados e as curvas de resposta para raios X e raios gama são calculadas pelo código de transporte de radiação MCNPX. Os espectros gama foram analisados pelo programa Alpino, que aplica o método de integração numérica da área sob os fotopicos de absorção total. Para as impurezas gama emissoras não detectadas visualmente, os limites de detecção foram calculados a partir da taxa de contagem de fundo, sob a área do pico de interesse. As soluções radioativas analisadas foram 67Ga,99Mo, 99mTc, 111In, 131I, 153Sm, 177Lu e 201Tl. Os resultados da relação entre a atividade do radionuclídeo em análise e as impurezas identificadas apresentaram acordo com os certificados de análise dos fabricantes, assim como, com as especificações da ANVISA. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
110

Functional network macroscopes for probing past and present Earth system dynamics

Donges, Jonathan Friedemann 14 January 2013 (has links)
Vom Standpunkt des Physikers aus gesehen, ist die Erde ein dynamisches System von großer Komplexität. Funktionale Netzwerke werden aus Beobachtungs-, und Modelldaten abgeleitet oder aufgrund theoretischer Überlegungen konstruiert. Indem sie statistische Zusammenhänge oder kausale Wirkbeziehungen zwischen der Dynamik gewisser Objekte, z.B. verschiedenen Sphären des Erdsystems, Prozessen oder lokalen Feldvariablen darstellen, bieten funktionale Netzwerke einen natürlichen Ansatz zur Bearbeitung fundamentaler Probleme der Erdsystemanalyse. Dazu gehören Fragen nach dominanten, dynamischen Mustern, Telekonnektionen und Rückkopplungsschleifen in der planetaren Maschinerie, sowie nach kritischen Elementen wie Schwellwerten, sogn. Flaschenhälsen und Schaltern im Erdsystem. Der erste Teil dieser Dissertation behandelt die Theorie komplexer Netzwerke und die netzwerkbasierte Zeitreihenanalyse. Die Beiträge zur Theorie komplexer Netzwerke beinhalten Maße und Modelle zur Analyse der Topologie (i) von Netzwerken wechselwirkender Netzwerke und (ii) Netzwerken mit ungleichen Knotengewichten, sowie (iii) eine analytische Theorie zur Beschreibung von räumlichen Netzwerken. Zur Zeitreihenanalyse werden (i) Rekurrenznetzwerke als eine theoretisch gut begründete, nichtlineare Methode zum Studium multivariater Zeitreihen vorgestellt. (ii) Gekoppelte Klimanetzwerke werden als ein exploratives Werkzeug der Datenanalyse zur quantitativen Charakterisierung der komplexen statistischen Interdependenzstruktur innerhalb und zwischen distinkten Feldern von Zeitreihen eingeführt. Im zweiten Teil der Arbeit werden Anwendungen zur Detektion von dynamischen Übergängen (Kipppunkten) in Zeitreihen, sowie zum Studium von Flaschenhälsen in der atmosphärischen Zirkulationsstruktur vorgestellt. Die Analyse von Paläoklimadaten deutet auf mögliche Zusammenhänge zwischen großskaligen Veränderungen der afrikanischen Klimadynamik während des Plio-Pleistozäns und Ereignissen in der Menschheitsevolution hin. / The Earth, as viewed from a physicist''s perspective, is a dynamical system of great complexity. Functional complex networks are inferred from observational data and model runs or constructed on the basis of theoretical considerations. Representing statistical interdependencies or causal interactions between objects (e.g., Earth system subdomains, processes, or local field variables), functional complex networks are conceptually well-suited for naturally addressing some of the fundamental questions of Earth system analysis concerning, among others, major dynamical patterns, teleconnections, and feedback loops in the planetary machinery, as well as critical elements such as thresholds, bottlenecks, and switches. The first part of this thesis concerns complex network theory and network-based time series analysis. Regarding complex network theory, the novel contributions include consistent frameworks for analyzing the topology of (i) general networks of interacting networks and (ii) networks with vertices of heterogeneously distributed weights, as well as (iii) an analytical theory for describing spatial networks. In the realm of time series analysis, (i) recurrence network analysis is put forward as a theoretically founded, nonlinear technique for the study of single, but possibly multivariate time series. (ii) Coupled climate networks are introduced as an exploratory tool of data analysis for quantitatively characterizing the intricate statistical interdependency structure within and between several fields of time series. The second part presents applications for detecting dynamical transitions (tipping points) in time series and studying bottlenecks in the atmosphere''s general circulation structure. The analysis of paleoclimate data reveals a possible influence of large-scale shifts in Plio-Pleistocene African climate variability on events in human evolution.

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