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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Hybrid permanent magnet machines for electric vehicles

Al-Adsani, Ahmad Saad January 2011 (has links)
In this research study, the feasibility of using one of the Hybrid Permanent Magnet (HPM) machine topologies acting as a generator with a passive rectification stage is considered. The primary application area is in the power-train of a series hybrid electric vehicle where the concept will be considered as an alternative to brushless PM machines interfacing to the vehicle power-train via active power electronic converters. The electro-magnetic design of the two main parts in the selected HPM generator topology and their individual system behaviour at normal and rated conditions will be studied. Prediction of the transient and steady state temperature in some of the HPM machine parts will be conducted based on commercial thermal analysis software. Two HPM machine stator winding configurations; 3-phase and 9-phase, with their relevant passive rectification stages will be analysed in terms of their terminal and DC-link output power along with the quality of the generated DC output voltage. An investigation of the operational characteristic of the HPM generator when delivering a fixed power at a fixed speed into a dynamic DC voltage source typical of a hybrid electric vehicle power-train subject to urban driving regimes will be presented. The research work will be a mixture of simulation studies using electro-magnetic finite element analysis (FEA), transient machine and system analysis via SimPower, a Matlab/Simulink toolbox set, along with test validation via a representative prototype HPM generator configuration and its interface to an experimental electrical system evaluation platform.
2

CONFIGURING TELEMETRY SYSTEMS FOR HIGH-POWER-MICROWAVE TESTING

Meyer, Steven 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California / During high-power microwave (HPM) testing, where the item under test is subjected to power levels up to several thousand W/cm , the RF energy present will make typical 2 telemetry RF links useless. Therefore, other means must be used to retrieve the data during the tests. One method to accomplish data retrieval is to replace the RF data link with a fiber-optic link. This is done by replacing the transmitter with a fiber-optic transmitter on the sending end and the RF receiver with a fiber-optic receiver on the receiving end. Although this sounds simple, it is not always so. Solutions for PCM and FM-FM systems are relatively straightforward, whereas PAM systems present a unique set of problems. This paper addresses possible solutions for PCM and FM-FM and three possible solutions for PAM, one being by using a PAM-to-PCM converter.
3

Vägen till ändrade levnadsvanor : -erfarenheter från personer med övervikt och fetma / The road to a healthier lifestyle : - overweight and obese patients’ experiences

Cecilia, Johansson, Kocevic, Fahira January 2017 (has links)
Några bidragande faktorer till övervikt och fetma är levnadsvanor som innefattar inaktivitet och felaktiga kostvanor. Personer med övervikt och fetma kan få hjälp från primärvården att påverka vikten till det bättre. Syfte med studien var att undersöka vilka erfarenheter personer med övervikt och fetma har av samtal om levnadsvanor med distriktssköterskan. Studien genomfördes som integrativ litteraturstudie vilket ger djupare förståelse för ett visst fenomen inom hälso-och sjukvården. Litteraturstudiens resultat baseras på 16 vetenskapliga artiklar. I analysen framkom fyra kategorier: Betydelsen av att bli motiverad, betydelsen av egen inställning till samtal om levnadsvanor, betydelsen av distriktssköterskans kommunikativa förmåga, betydelsen av distriktssköterskans kunskap och kompetens. Distriktssköterskans kommunaktion var avgörande för hur patienten upplevde samtalet om levnadsvanor. När distriktssköterskan tillsammans med patienten satte upp mål och råden individanpassades motiverades patienten att ändra levnadsvanor. Patienternas motivation minskade när de upplevde att råden de fått var generella. Vissa patienter upplevde att distriktssköterskan inte hade tillräckligt med kunskap för att hantera övervikt och fetma. Kategorierna visar sig överensstämma med Penders hälsofrämjande arbetsmodell som förklaringsmodell för förståelse för patientens motivation till ändrade levnadsvanor. / Some factors that contribute to overweight and obesity are lifestyle related and comprise a lack of physical activity and poor nutrition. Overweight and obese individuals may seek medical attention and acquire advice on how to lose their weight. The purpose of this study was to look into the experiences of the overweight and obese patients pertaining to lifestyle conversations with the district nurse. The study was conducted as an integrative literature overview, which enables a better understanding of a certain phenomenon within medical service. The results consist of sixteen scientific articles. The analysis reveals four categories: the significance of becoming motivated, the significance of one’s own attitude towards conversations about lifestyle, the significance of the district nurse’s communicative skills and the district nurse’s knowledge and competence. The communicative skills of the district nurse played a pivotal role in how the conversations about lifestyle were perceived by the patients. When the district nurse and the patient set individual goals together, the patient appeared more motivated to make a lifestyle change. On the other hand, the motivation of the patient decreased when the advice received was too generalized. Moreover, some patients believed that the district nurse was not adequately knowledgeable to deal with overweight and obesity. The categories correlate with Pender's health-promoting model as an explanation of patients' motivation in changing their lifestyles.
4

Theoretical analysis and simulation of microwave-generation from a coaxial vircator

Hägg, Martin January 2017 (has links)
High-power microwave, HPM, systems can be used as non-lethal weapons with the ability to destroy or disturb electronics, by damaging internal circuits and inducing high currents. Today microwave sources are being developed with peak powers exceeding 1 GW, one of these devices is the vircator, a narrowband source which is unique to the HPM community. In order to understand and develop microwave sources like the vircator it is necessary to have computer models, as simulations gives an invaluable understanding of the mechanisms involved during operation, saving time and development costs.                                                                  This thesis presents the results from a theoretical analysis and a simulation study using a well known electromagnetic particle-in-cell code, Computer Simulation Technology Particle Studio. The results are then compared to measured data from a HPM system, the Bofors HPM Blackout. The results show that CST PS can be used to design and study the coaxial vircator with good results.
5

Processamento remoto em solução para interação com ambientes arquitetônicos 3D através de tablets

Rabello, Guilherme Picanço 07 March 2016 (has links)
Submitted by Luciana Sebin (lusebin@ufscar.br) on 2016-10-05T18:53:36Z No. of bitstreams: 1 DissGPR.pdf: 4260232 bytes, checksum: 502932c8b3d277cbd1c02a8b1b48b913 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-13T20:18:54Z (GMT) No. of bitstreams: 1 DissGPR.pdf: 4260232 bytes, checksum: 502932c8b3d277cbd1c02a8b1b48b913 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-13T20:19:05Z (GMT) No. of bitstreams: 1 DissGPR.pdf: 4260232 bytes, checksum: 502932c8b3d277cbd1c02a8b1b48b913 (MD5) / Made available in DSpace on 2016-10-13T20:19:14Z (GMT). No. of bitstreams: 1 DissGPR.pdf: 4260232 bytes, checksum: 502932c8b3d277cbd1c02a8b1b48b913 (MD5) Previous issue date: 2016-03-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / The evolution of Computer Graphics, supported by the computational development, enables increasingly advanced visual creations and promotes benefits to various areas such as: Art, architecture, Product Design, Visual Design, Games, Movies, Engineering, GIS and Medicine. However, the processing power needed for applications that require a high degree of realism, restricts the use of these applications to a small portion of the entire range of the computing devices in use by the population. Recently, the evolution of mobile network technologies brought a possible solution to the inability of most mobile devices in dealing with interactive applications and a high degree of realism. The solution is based on the remote processing of applications on servers with high processing capacity, and delivery of the images produced for mobile devices made by its conversion into video and streaming broadcasts. This master dissertation explores a remote processing solution for interacting with architectural environments through tablets. Emphasis was placed in: keeping high degree of realism, difficult to achieve due to the processing requirements in real-time interactive applications; the adaptation and combination of tools available in the market; and in mitigating latency through different ways of user interaction. The evaluation of the results was carried out in training sessions, interaction and interviews with volunteers. / A evolução da Computação Gráfica apoiada no desenvolvimento computacional possibilita criações visuais cada vez mais avançadas promovendo benefícios a diversas áreas como: Artes, Arquitetura, Design de produto, Design visual, Jogos, Cinema, Engenharia, Geoprocessamento e Medicina. Porém, a capacidade de processamento exigida por aplicações que requerem elevado grau de realismo restringe o uso dessas aplicações a uma parcela pequena de toda a gama de dispositivos computacionais instalados e de uso da população. Recentemente, a evolução das tecnologias de rede móvel trouxe uma possível solução à incapacidade da maioria dos dispositivos móveis em lidar com aplicações interativas e de elevado grau de realismo. A solução baseia-se no processamento remoto das aplicações, em servidores com elevada capacidade de processamento, e na entrega das imagens produzidas para os dispositivos móveis feita através de sua conversão em vídeo e transmissão por streaming. Este trabalho explora uma solução de processamento remoto para interação com ambientes arquitetônicos através de tablets. Deu-se ênfase às questões de manutenção de elevado grau de realismo, dificultada pelas exigências de processamento em tempo real de aplicações interativas, à adaptação e combinação de ferramental disponível no mercado e à mitigação da latência através de recursos de interface com usuário. A avaliação dos resultados foi realizada em sessões de treinamento, interação e entrevistas com usuários voluntários.
6

HPM-vapen vs. kommersiell UAV

Eriksson, Kjell January 2016 (has links)
Detta arbete i militärteknik studerar om högeffektpulsad mikrovågsstrålning kan uppnå verkan mot kommersiella UAV. Analysen genomförs på två olika icke-dödliga HPM-vapen. Data hämtas från ett scenario där vapenverkan innebär hög risk för skada på tredje man. En Försvarsmaktsstudie har konstaterat att Luftvärnsbataljon saknar förmåga att verka mot små UAV.Dagsaktuell kunskap har inhämtats om scenariots miljö samt från forskning och industri genom studiebesök. Inhämtad kunskap har möjliggjort en logisk-matematisk parameterstudie på ett scenario med militärtekniskt perspektiv. Analysens slutsatser är att kommersiella UAV innehar låg skyddsnivå, att beslut om insats underlättas i alla miljöer och att en elektronisk sköld i form av HPM-vapen skyddar en stor volym samtidigt. HPM-vapen kan inte som ensamt vapensystem stå för skydd och uppnå säkerställd verkan mot kommersiell UAV. HPM-vapen kan däremot komplettera övriga verkanssystem och göra luftförsvaret starkare genom system av system. HPM-vapen kan bidra till att minska ett befintligt förmågeglapp mot kommersiella UAV. / This paper in military technology discusses whether high power microwaves can affect commercial UAVs. Two non-lethal HPM-weapons are analyzed. The data is collected from a scenario where there is a high risk for collateral damage. A Swedish Armed Forces study stated that the Air Defence Battalion lacks ability to affect small UAVs. The latest knowledge is obtained from the environment in the scenario, from research and from the industry. This knowledge has enabled a logical-mathematical parametric study on the scenario within a military perspective. The result of the study is the assessment that commercial UAVs are assessed to have low protection factor, facilitates decision to act in all environments and provides an electronic shield protection of a large surface at the same time. HPM-weapons can´t stand as a single system for protection against commercial UAVs and achieve guaranteed effect. However, HPM-weapons can complement other weapon systems and thus make the air defense stronger through systems of systems. HPM-weapons can reduce the capability deficiency against commercial UAVs.
7

Investigation of Limiters For HPM and UWB Front-door Protection / Undersökning av limitrar för HPM och UWB framvägskopplingsskydd

Nilsson, Tony January 2006 (has links)
<p>An extensive investigation of front-door protection devices i.e. limiters has been made. The thesis work contains both HPM- and UWB-measurements done on various limiters, in order to characterize them. The measurements show that all limiters are not suitable as protection against HPM- and UWB-pulses. The limiters that were found to provide the best protection are limiters based on diode technologies. PIN- and Schottky-diodes generally shows very good performance and they fulfill many parameters that have been set by FOI. To obtain a full protection it is presumably necessary to use two or more limiters in combination, which complement each other.</p> / <p>En omfattande studie av framvägskopplingsskydd, dvs. limiters har gjorts. Examensarbetet innehåller resultat från både HPM- och UWB- mätningar som har gjorts på olika limitrar för att karaktärisera deras prestanda. Av resultaten från mätningarna kan man se att alla limitrar inte passar som skydd mot HPM- och UWB-pulser. De limitrar som tillhandahöll det bästa skyddet var baserade på olika diodtekniker. PIN- och Schottky-dioder visade sig överlag ha väldigt goda prestanda och de uppfyller många av de parametrar som bestämts av FOI. För att få ett heltäckande skydd är det förmodligen nödvändigt att man använder två eller flera limitrar i kombination, som kompletterar varandra.</p>
8

IC-påverkan av elektromagnetisk puls / Effects of electromagnetic pulse on integrated circuit

Lindskog, Claes January 2008 (has links)
Detta examensarbete undersöker effekter av en elektromagnetisk puls på IC-kretsar. För att kunna utvärdera inverkan har ett testobjekt, innehållande komponenter som skall testas, konstruerats. Detta testobjekt består av batteri, en enkel komponent och last. Ett pulsaggregat och en antenn användes för att generera de elektromagnetiska pulser som testobjektet utsattes för. Resultaten visar att inverkan på de testade komponenterna är möjlig. Inverkan visade sig vara beroende av bl.a. avståndet till antennen och den tid som testobjektet utsätts för störning. Störning har också utförts vid olika polariseringar. Ett mål var att kunna jämföra en elektromagnetisk störning via en antenn med en trådbunden störning, där pulsen genererats från samma pulsaggregat. Försöken att utföra trådbunden störning av testobjektet misslyckades då pulsen inte var tillräckligt bra. Detta examensarbete är en del av en artikel, High Power Ultra Wide Band and Vircator Source-Victim Experiment, som presenterades vid konferensen EMC Europe 2008. / This paper studies the effects of an electromagnetic pulse on IC-circuits. A DUT (device under test) has been constructed so that the effects of the pulse can be evaluated. The DUT consists of a battery, a load and the component, which is to be tested. A high voltage power supply and an antenna were used to generate the pulses that the DUT were exposed to. The results show that the effects were dependent on, among others, the distance between the antenna and the DUT and the time during which the DUT was exposed to the pulse. The DUT has also been exposed to different polarisations of the pulse. One of the objectives of the study was to compare the difference between a pulse from an antenna and from a wire. This was to be done with the same high voltage power supply. Attempts to use a wire, for injecting the pulse, were unsuccessful since the damped pulse was not satisfying. This paper is a part of a paper, High Power Ultra Wide Band and Vircator Source-Victim Experiment, that was presented at the conference EMC Europe 2008.
9

Investigation of Limiters For HPM and UWB Front-door Protection / Undersökning av limitrar för HPM och UWB framvägskopplingsskydd

Nilsson, Tony January 2006 (has links)
An extensive investigation of front-door protection devices i.e. limiters has been made. The thesis work contains both HPM- and UWB-measurements done on various limiters, in order to characterize them. The measurements show that all limiters are not suitable as protection against HPM- and UWB-pulses. The limiters that were found to provide the best protection are limiters based on diode technologies. PIN- and Schottky-diodes generally shows very good performance and they fulfill many parameters that have been set by FOI. To obtain a full protection it is presumably necessary to use two or more limiters in combination, which complement each other. / En omfattande studie av framvägskopplingsskydd, dvs. limiters har gjorts. Examensarbetet innehåller resultat från både HPM- och UWB- mätningar som har gjorts på olika limitrar för att karaktärisera deras prestanda. Av resultaten från mätningarna kan man se att alla limitrar inte passar som skydd mot HPM- och UWB-pulser. De limitrar som tillhandahöll det bästa skyddet var baserade på olika diodtekniker. PIN- och Schottky-dioder visade sig överlag ha väldigt goda prestanda och de uppfyller många av de parametrar som bestämts av FOI. För att få ett heltäckande skydd är det förmodligen nödvändigt att man använder två eller flera limitrar i kombination, som kompletterar varandra.
10

IC-påverkan av elektromagnetisk puls / Effects of electromagnetic pulse on integrated circuit

Lindskog, Claes January 2008 (has links)
<p>Detta examensarbete undersöker effekter av en elektromagnetisk puls på IC-kretsar.</p><p>För att kunna utvärdera inverkan har ett testobjekt, innehållande komponenter som skall testas, konstruerats. Detta testobjekt består av batteri, en enkel komponent och last. Ett pulsaggregat och en antenn användes för att generera de elektromagnetiska pulser som testobjektet utsattes för. Resultaten visar att inverkan på de testade komponenterna är möjlig. Inverkan visade sig vara beroende av bl.a. avståndet till antennen och den tid som testobjektet utsätts för störning. Störning har också utförts vid olika polariseringar.</p><p>Ett mål var att kunna jämföra en elektromagnetisk störning via en antenn med en trådbunden störning, där pulsen genererats från samma pulsaggregat. Försöken att utföra trådbunden störning av testobjektet misslyckades då pulsen inte var tillräckligt bra.</p><p>Detta examensarbete är en del av en artikel, <em>High Power Ultra Wide Band </em>and <em>Vircator Source-Victim Experiment</em>, som presenterades vid konferensen EMC Europe 2008.</p> / <p>This paper studies the effects of an electromagnetic pulse on IC-circuits. A DUT (device under test) has been constructed so that the effects of the pulse can be evaluated. The DUT consists of a battery, a load and the component, which is to be tested. A high voltage power supply and an antenna were used to generate the pulses that the DUT were exposed to. The results show that the effects were dependent on, among others, the distance between the antenna and the DUT and the time during which the DUT was exposed to the pulse. The DUT has also been exposed to different polarisations of the pulse.</p><p>One of the objectives of the study was to compare the difference between a pulse from an antenna and from a wire. This was to be done with the same high voltage power supply. Attempts to use a wire, for injecting the pulse, were unsuccessful since the damped pulse was not satisfying.</p><p>This paper is a part of a paper, <em>High Power Ultra Wide Band</em> and <em>Vircator Source-Victim Experiment</em>, that was presented at the conference EMC Europe 2008.</p>

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