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A SuperDARN Study of Steady Magnetospheric ConvectionPfeifer, Jeff Bruce 08 July 2008
Intervals of Steady Magnetospheric Convection (SMC) are loosely defined as times when convection in the magnetosphere as a whole is enhanced and there are no substorm signatures. A lack of substorm signatures implies that the large scale structure of the magnetotail is maintained. There have been several quantitative methods developed to detect SMC events. None of these methods are based on observations of convection. The Super Dual Auroral Radar Network (SuperDARN) is a useful tool for studying SMC, because it gives a direct measurement of convection on a global scale. Previous SMC selection methods have made use of ground based magnetometer responses to auroral currents in the atmosphere. These methods resulted in a strong seasonal dependence in SMC occurrence due to seasonal changes in ionospheric conductivity. A new SMC selection criterion was developed to improve upon the previous criteria. This new method identifies all the events found using currently accepted methods plus additional intervals that reduce the seasonal dependence in SMC occurrence. SuperDARN was used to evaluate the old and new selection methods. According to SuperDARN convection observations, the new SMC selection criterion largely eliminated ionospheric conductivity effects. A conceptual model of the conductivity effects on the traditional SMC selection method was developed, and the occurrence of modelled SMC events agrees well with observations. Statistical studies have revealed that the additional SMC intervals have similar properties as events selected using traditional methods. Case studies confirmed the statistical results that SMCs selected by the new criterion have SMC properties. Both SMC events sets have a moderate solar wind driver, enhanced convection, and stable polar cap size. Statistical studies have also shown there was good SuperDARN data coverage during SMC, which is not typical of SuperDARN observations during enhanced and disturbed conditions in the magnetosphere. It is therefore shown to be an excellent tool with which to study SMC.
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A SuperDARN Study of Steady Magnetospheric ConvectionPfeifer, Jeff Bruce 08 July 2008 (has links)
Intervals of Steady Magnetospheric Convection (SMC) are loosely defined as times when convection in the magnetosphere as a whole is enhanced and there are no substorm signatures. A lack of substorm signatures implies that the large scale structure of the magnetotail is maintained. There have been several quantitative methods developed to detect SMC events. None of these methods are based on observations of convection. The Super Dual Auroral Radar Network (SuperDARN) is a useful tool for studying SMC, because it gives a direct measurement of convection on a global scale. Previous SMC selection methods have made use of ground based magnetometer responses to auroral currents in the atmosphere. These methods resulted in a strong seasonal dependence in SMC occurrence due to seasonal changes in ionospheric conductivity. A new SMC selection criterion was developed to improve upon the previous criteria. This new method identifies all the events found using currently accepted methods plus additional intervals that reduce the seasonal dependence in SMC occurrence. SuperDARN was used to evaluate the old and new selection methods. According to SuperDARN convection observations, the new SMC selection criterion largely eliminated ionospheric conductivity effects. A conceptual model of the conductivity effects on the traditional SMC selection method was developed, and the occurrence of modelled SMC events agrees well with observations. Statistical studies have revealed that the additional SMC intervals have similar properties as events selected using traditional methods. Case studies confirmed the statistical results that SMCs selected by the new criterion have SMC properties. Both SMC events sets have a moderate solar wind driver, enhanced convection, and stable polar cap size. Statistical studies have also shown there was good SuperDARN data coverage during SMC, which is not typical of SuperDARN observations during enhanced and disturbed conditions in the magnetosphere. It is therefore shown to be an excellent tool with which to study SMC.
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A Study of Application of SMC on the Sizihwan Artificial Nourishment ProjectChen, Pin-yi 29 July 2009 (has links)
About the software of numerical model, countries to develop model must be base on their main local coast. And the parameters of the software will be built to fit their local coast. But coast are different from every countries. If use the parameters to simulation in Taiwan, the result may be wrong.
The study of this paper use SMC(coastal modeling system). To match up different kind of parameters, such as wave¡Bperiod¡Btide to simulate. Search and collect the data on the study of local area over the years. Although first to confer the change of bathymetry on Sizihwan, which influence on the wave of typhoon and monsoon. To understand the bathymetry influence on different type of waves. Then simulate the change of the sea bed by the module of SMC ' Mopla. And compare the result of simulate and the measurement, to probe into the change of bathymetry.
The influence of the waves of southwest monsoon on Sizihwan, the characteristic was erosion close-shore and accretion off-shore on the beach. The influence of the waves of northwest monsoon, the characteristic was wave induce the berm. There are best result of simulate the waves of southwest monsoon, but bad at the waves of northwest monsoon.
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Řízení modelu linky SMC MAP 205 / The manipulator SMC MAP 205 controlĎuriš, Martin January 2015 (has links)
The thesis deal with a model of electronically controlled assembly minicell MAP-205 based on pneumatic drives and its debugging. Assembly minicell simulates assembling and disassembling of simple four item assembly. Minicell is controlled by Phoenix Contact ILC 150ETH programmable logic controller. The minicell control program is composed of several subroutines/subprograms providing various functionalities to assembly minicell. There is integrated HMI created in Control Web application too. It allows to display actual status of each component and to control each drive in manual mode. Communication between HMI based on PC and PLC controller is supported by Bluetooth module and OPC server.
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Applications of Sliding Mode Controller and Linear Active Disturbance Rejection Controller to a PMSM Speed SystemZhao, Yang 07 August 2013 (has links)
No description available.
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Further characterisation of the rad18 gene of Schizosaccharomyces pombeMunday, Caroline Anne January 1998 (has links)
No description available.
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Mechanical recycling of automotive composites for use as reinforcement in thermoset compositesPalmer, James Alexander Thomas January 2009 (has links)
The aim of this research was to investigate the potential use of recycled glass fibre composite materials as a replacement for virgin reinforcing materials in new thermoset composites. Specifically the closed-loop mechanical recycling of composites used heavily in the automotive sector known as dough and sheet moulding composites, DMC and SMC respectively, are investigated. The recycling of glass reinforced thermoset polymer composite materials has been an area of investigation for many years and composites used in the automotive industry are of particular interest due to legislative and social pressures on the industry. The mechanical recycling process and then collection of useful fibrous grades of recycled materials, recyclate, by a novel air separation technique were investigated first. The properties of these recyclate fibres were characterised and compared directly with the properties of virgin glass fibres they were to be used to replace. Single fibre tensile tests were employed to compare the strengths of the fibres and single fibre pull-out tests were used to investigate the strength of the interface between the fibres and a polyester matrix. These tests showed the recyclate fibres to be weaker and have a poorer interface with the polyester matrix than the virgin glass fibres. Understanding the properties of the recyclate materials meant their reformulation into new composites could be carefully considered for the production of new high performance materials. Two grades of the collected recyclate materials were then reformulated in to new DMC and SMC composites, replacing percentages of the virgin glass fibre reinforcement. The mechanical properties of the resulting manufactured composites were characterised throughout for direct comparison against one another and an unmodified control material, using both three-point flexural tests and Charpy impact tests. Through the modification of existing manufacturing techniques and the development of novel production equipment it has been possible to successfully manufacture both DMC and SMC composites with the recyclate materials used to replace virgin glass fibres. Virgin glass fibres have successfully been replaced by recyclate materials without disrupting standard production techniques and with minimal reduction of the mechanical properties of the resulting composites. As the loadings of recyclate materials used were greatly increased both the flexural and impact strengths were significantly degraded and it was found that chemical modification of the composite could be used to improve these formulations. It has been shown that the recyclate materials should be considered and treated as a distinct reinforcing ingredient, separately from the remaining virgin glass fibres.
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Modelação de quebramares destacadosCosta, Gustavo Manuel Santos da January 2009 (has links)
Tese de mestrado integrado. Engenharia Civil (Especialização em Hidráulica). Faculdade de Engenharia. Universidade do Porto. 2009
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A dinâmica sedimentar e a caracterização de Zonas de Erosão Acentuada (ZEA) ao longo do arco praial de Massaguaçu, SP / The sediment dynamics and the characterization of erosional Hot Spot (EHS) in Massaguaçu beach, SPRogacheski, Carlos Eduardo 10 November 2010 (has links)
Nas últimas décadas, a praia de Massaguaçu vem sofrendo processos erosivos intensos, cujos segmentos possuem taxas de recuo acentuadas, denominadas Zonas de Erosão Acentuada (ZEAs). Partindo deste problema este trabalho se propôs a entender a dinâmica sedimentar do arco praial de Massaguaçu e das possíveis causas de formação e manutenção das ZEAs. A coleta de dados se baseou no levantamento batimétrico e do clima de ondas, bem como no levantamento sonográfico de varredura lateral e na coleta de amostras de sedimento de superfície da antepraia de Massaguaçu. Para processar os dados se optou pela aplicação da modelagem numérica utilizando o modelo SWAN (propagação de ondas em águas profundas) e o modelo SMC (módulos OLUCA, COPLA e EROS, que trabalham, respectivamente, com propagação de ondas em águas rasas, simulação de correntes e simulação de transporte sedimentar). Para a formulação da discussão foram selecionados os 6 (seis) casos que apresentaram as condições de ondas mais representativas. Tais casos mostraram que a dinâmica sedimentar e os processos costeiros responsáveis pela formação e manutenção das ZEAs são controlados por dois padrões distintos de ondas incidentes. O primeiro padrão está relacionado às ondas vindas de NE - E, que geram correntes longitudinais para o sul. Suas correntes longitudinais e transversais à costa são de baixa intensidade resultando em um transporte sedimentar e em variações da morfologia praial menos intensos, além de formar células de circulação em vórtices. O segundo padrão, por sua vez, está relacionado às ondas oriundas SSE - SE - ESSE, cujas correntes litorâneas longitudinais rumam ao norte. Tais correntes longitudinais e transversais à costa, apresentam uma intensidade maior, portanto o transporte sedimentar e as variações da morfologia ao longo do arco praial são maiores bem como as células de circulação em vórtices. Partindo desses resultados, percebeu-se que as ZEAs em Massaguaçu estão ligadas a um possível aumento na frequência e na intensidade das tempestades ao longo das últimas décadas e até o presente momento, não há mecanismos naturais que revertam esta retração da linha de costa. / Over the past decades in Massaguaçu beach has happening a strong erosion process with segments that have higher retreat rates, commonly termed as Erosional Hot Spots (EHSs). This research aims the understanding of the sedimentary dynamics along the Massaguaçu embayment and also the possible causes of the formation and maintenance of the EHSs. The methodology was separately on two steps. At first we collected bathymetry, wave and side-scan sonar data, and samples of the surface sediments from the shoreface of Massaguaçu beach. Later, to analyze majority data, we chose to use numerical modeling based on the SWAN model (propagation of waves in deep water) and SMC model (modules OLUCA, COPLA and EROS, that work respectively with the propagation of waves in shallow water, the simulation of currents and finally the simulation of sediment transport). After modeling, we were able to select the 6 (six) most representative wave conditions cases. Those results show that the control of the sediment dynamics and the coastal processes responsible for the formation and the maintenance of ZEA are based on the characteristics of the incident waves. On trying to explain that process, it was possible to recognize two distinct patterns. The first pattern observed is associated with the NE - E waves, generating longshore currents to the south. In this case, both the longshore and the crosshore currents are less intense, forming cells circulation in vortex, resulting in minor variations in sediment transport and beach morphology. The second pattern is related with the SSE - SE - ESE waves, generating longshore currents to the north. In this case both the longshore and the crosshore currents are more intense, although still with occurrence of forming cells circulation in vortex, resulting in a larger sediment transport and morphological changes along the beach. Finally, what we have seem was that the ZEAs in Massaguaçu are possibly linked to a potential increment on storms frequency and intensity over the past decades and unfortunately, at present, there is still no mechanism to recover this natural retreat of the coastline.
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Modélisation multi-échelles de l'endommagement d'un composite à résine thermodurcissable renforcé de fibres courtes de carbones / Multiscale damage modelling of a thermoset composite reinforced by short carbon fibersNony, Clément 20 April 2018 (has links)
L'évolution du contexte industriel pousse l'industrie du transport, et plus particulièrement le secteur automobile, à réaliser des gains de de masse. Ceci passe, pour partie, par le développement de nouvelles solutions en matériaux composites. Le présent travail de thèse est consacré à la caractérisation mécanique et à la modélisation micromécanique d'un nouveau matériau composite SMC renforcé de mèches de fibres de carbone. L'objectif est de constituer une première base de connaissances sur le comportement de ce SMC en fatigue. Les investigations expérimentales passent notamment par l'analyse de la microstructure, la caractérisation du comportement mécanique sous sollicitation quasi-statique et de fatigue ainsi que par l'analyse des modes de dégradations. L'approche multi-échelle développée prend en compte la microstructure du matériau aux deux échelles mises en évidence à travers deux homogénéisations successives par une méthode Mori-Tanaka. Cette stratégie de modélisation permet de relier le comportement des fibres et le comportement élasto-plastique de la matrice à travers une loi de comportement dédiée à celui du matériau composite, et enfin d'intégrer la distribution d'orientation des mèches induites par le procédé de thermocompression.Le modèle multi-échelle a été identifié par une méthode inverse à partir des bases de données expérimentales constituées lors des travaux. La loi constitutive globale, à l'échelle d'un volume élémentaire représentatif, a été implémentée dans la bibliothèque scientifique SMART+ en langage C++ et a été conçue pour être compatible dans le cadre d'analyse de structures par éléments finis. En régime non-linéaire intégrant l’endommagement. / The evolution of the industrial context is pushing the transport industry, and more specifically the automotive sector, toward better energy efficiency. This objective is partly achieved by the development of new composite material solutions. The current work is devoted to the mechanical characterization and the multiscale modeling of a new SMC composite material reinforced with short carbon fibers bundles. The objective is to build a first knowledge base on the behavior of this SMC under fatigue loading. Experimental investigations include the analysis of the microstructure, the characterization of the mechanical behavior under quasi-static and fatigue loading, as well as the analysis of the damage mechanisms. The proposed multiscale approach takes into account the microstructure of the composite at the two scales highlighted through two successive homogenizations by the means of a Mori-Tanaka based method. Such modelling strategy makes it possible to relate elasto-plastic behavior of the matrix through dedicated local constitutive laws and the behavior of the fibers to that of the composite material, and to integrate the orientation distribution of the bundles induced by the manufacturing process... The multiscale model was identified by the mean of an inverse computation method applied on the experimental results taken from the databases created during the works.The global constitutive law, computed at the scale of a representative elementary volume, has been implemented in the SMART+ scientific library in C++ language in such a manner to be compatible in a finite element analysis (FEA) framework.
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