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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.
71

Étude du vieillissement calendaire des supercondensateurs et impact des ondulations de courant haute fréquence / Study of supercapacitors floating ageing and impact of high frequency current ripple

German, Ronan Louis 10 December 2013 (has links)
Les travaux de recherche sont consacrés au vieillissement des supercondensateurs (SC) à double couche électrique dans un réseau électrique embarqué soumis à des ondulations de courant de haute fréquence (par exemple celui d'un véhicule hybride). Les SC étudiés sont des composants commerciaux représentatifs de la technologie la plus utilisée (acetonitrile / charbon actif) dans les applications de transport. Les travaux présentent des résultats d'essais de vieillissement calendaires (c'est-à-dire à tension et à température constantes). Le suivi de l'état de santé des SC s'effectue à l'aide de l'évolution de leur impédance au cours des essais de vieillissement. Plusieurs modèles d'impédances classiques sont présentés (modèle CPE et modèle simple pore) ainsi qu'un modèle récent (modèle multipore). Les paramètres de chaque modèle d'impédance sont systématiquement liés à des grandeurs électrochimiques des SC représentatives de l'état de leurs électrodes. Grâce au modèle multipore, les pores des électrodes du SC peuvent être classés selon leur constante de temps électrique (liée sous certaines hypothèses au diamètre d'ouverture des pores). L'application du modèle multipore aux résultats du vieillissement calendaire permet de mettre en évidence un effet drastique du début de vieillissement sur les pores possédant un faible diamètre d'ouverture. Les ondulations de courant haute fréquence semblent quant à elles transparentes en ce qui concerne le vieillissement c'est-à-dire qu'elles influencent très peu le vieillissement des SC. On note enfin un effet non négligeable des arrêts de vieillissement sur l'état de santé des SC / Those research works are about double layer supercapacitors ageing placed in an onboard power network subject to high frequency current ripple (in a hybrid vehicle for instance). Studied SC are commercial components, representative of the most used technology (i.e. Acetonitrile / Active carbon) in transports domain. SC floating ageing results (constant temperature and constant voltage) are presented. SC health monitoring is achieved by using SC impedance evolution through ageing test. Classic impedance models (CPE and single pore model) are presented as well as a newer model (called multipore model). Model parameters are systematically linked to electrochemical data related to SC state of health. Multipore model enable to classify pores thanks to their electrical time constant (related to pore diameter under some hypothesis). The evolution of multipore model parameters under floating constraints shows that the smaller pores are more affected by beginning of ageing test. HF current ripple seem not to affect supercapacitors floating ageing. Whereas we notice effect of ageing stopping periods on SC state of health
72

Řízení oběžného majetku podniku a jeho financování / Management of the Floating Capital of a Firm and its Financing

Juričková, Lenka January 2009 (has links)
Summary of theoretical knowledge about Floating Capital, its individual components, ways of management and financing, and achievement Floating Capital analysis and ways of financing analysis in company Edscha Tools, a. s.
73

Optimization of floating PV systems : Case study for a shrimp farm in Thailand

Louise, Wästhage January 2017 (has links)
The use of solar photovoltaic (PV) systems have expanded rapidly the last decade and today’s market includes several different solar utilizations, where floating PV is one of them. Previous studies have shown how floating PV systems increase the PV efficiency and at the same time reduce the water evaporation. The purpose of this study is to evaluate and optimize energy solutions using floating PV systems for a shrimp farm cultivation in Thailand, where the technical, environmental and economic aspects will be included. The optimizations have been done in the open source model OptiCE, where genetic algorithm (AG) have been used to maximize the renewable reliability and minimize the Levelized Costs of Electricity (LCOE). In order to find the optimal renewable solution for the investigated shrimp farm, four scenarios have been compared considering different PV system combinations. The simulated results showed how the scenarios considering floating PV system generated a higher reliability than the scenarios considering ground-mounted PV system. The scenario considered tracking PV system increased the system´s renewable reliability compared to fixed PV system. However the shrimp farm is connected to the national electric grid or not will have a huge impact on the LCOE due to the low electric price and the implemented feed-in-tariff (FIT) program. The size of the installed PV capacity significantly affects the reliability results were the capacity of 200 kWp reaches a reliability of almost 100%. The optimal solution for the investigated shrimp farm to become independent is therefore to install a combined floating PV and battery storage system.
74

Automatische vektorbezogene Generierung von Straßennetzabbildern auf Basis von Floating Car Data: Automatische vektorbezogene Generierung von Straßennetzabbildern auf Basis von Floating Car Data

Körner, Matthias, Krimmling, Jürgen, Oertel, Robert 24 July 2012 (has links)
Straßen-Knoten-Netze als modelliertes Abbild der Straßeninfrastruktur bilden die Grundlage für eine Vielzahl von Diensten und Anwendungen. Die Verortung von Fahrzeugen, aber auch die Verkehrsumlegung, basieren darauf. Die Ermittlung optimaler Routen und die Visualisierung der Verkehrslage werden ermöglicht. Die resultierenden Anforderungen an das Netzabbild sind vielfältig und deren Bewältigung mit nicht unerheblichem Aufwand verbunden. Kernpunkte sind Genauigkeit, Aktualität und Flächendeckung. Ferner werden geringe Kosten bei dessen Erstellung angestrebt. Als Ergänzung zu manueller Digitalisierung und der Erfassung durch Messfahrzeuge mit hochpräziser Ortung stellt die Nutzbarmachung von Mehrwerten aus Floating Car Systemen einen viel versprechenden Ansatz dar. Vorgestellt wird ein Verfahren, welches mittels eines vektorbasierten Ansatzes Straßen-Knoten-Netze aus Floating Car Daten ermittelt. / Node-edge-networks representing road infrastructure are base for various applications and services. Georeferencing of vehicles as well as traffic assignment are based on. Routing and traffic conditions visualisation become possible. Requirements concerning precision, topicality and area coverage of road network image are caused by. Low costs are aspired as well. Utilisation of additional benefits from floating car systems is a promising approach, supplementing common technologies like manual digitalisation or capturing road trajectories by special equipped probe vehicle. A vector based method aggregating positions information of floating car to process road infrastructure images will be presented.
75

Investigating Wind Data and Configuration of Wind Turbines for a Turning Floating Platform

Sönmez, Nurcan January 2014 (has links)
Wake interactions on a floating platform for offshore wind energy applications were investigated. The study is performed in collaboration with Hexicon AB which has a patent family for innovative floating platforms, which are able to turn automatically. The Jensen model is used for wake effect calculations and the simulations were performed in MATLAB. The present study starts with wind speed and wind direction data analysis for the specific site that Hexicon AB plans to construct its first platform. Data analysis is followed by wake interaction studies for H4-24MW type Hexicon AB platform. Wake interaction simulations were performed for three different cases. Fixed turbine and platform, Nacelle yawing and fixed platform and Nacelle yawing and turned platform. Different cases were investigated in order to see wake interactions for different wind directions. Wind direction effect on wake interactions were performed between _90_ and 90_ with an increment of 10_. After having the simulation results for Nacelle yawing and turned platform case the results were compared with ANSYS - CFX simulations results. The results didn’t match exactly but they were very close, which is an indicator to the validity of the Jensen Model. After finding out the possible behavior of wake interactions for different wind directions, power calculations were performed for the same three cases. In order to perform the power calculations the wake interactions for different wind directions were taken into account. In case of platform turning it was assumed that power losses were caused both by wake interactions and in case of thrusters activation. The losses that would be caused by different thrust forces on the turbine blades were not included. The last study was performed to suggest different layouts. In the second case, Nacelle yawing and fixed platform, it was found out that nacelle yawing for most of the angles is not possible because it creates wake regions in front of the rotor area. It was decided to propose new turbine configurations on the platform which are tolerant to different nacelle yawing angles. The simulations were run without considering any constructions limitations, meaning that the availability of platform structure was not included. The study is ended by performing some probabilistic results for platform turning behavior.
76

Investigating Wind Data and Configuration of Wind Turbines for a Turning Floating Platform.

Sönmez, Nurcan January 2014 (has links)
Wake interactions on a floating platform for offshore wind energy applications were investigated.The study is performed in collaboration with Hexicon AB which has a patent family for innovative floating platforms, which are able to turn automatically. The Jensen model is used for wake effect calculations and the simulations were performed in MATLAB. The present study starts with wind speed and wind direction data analysis for the specific site that Hexicon AB plans to construct its first platform. Data analysis is followed by wake interaction studies for H4-24MW type Hexicon AB platform. Wake interaction simulations were performed for three different cases. Fixed turbine and platform, Nacelle yawing and fixed platform and Nacelle yawing and turned platform. Different cases were investigated in order to see wake interactions for different wind directions. Wind direction effect on wake interactions were performed between _90_ and 90_ with an increment of 10_. After having the simulation results for Nacelle yawing and turned platform case the results were compared with ANSYS - CFX simulations results. The results didn’t match exactly but they were very close, which is an indicator to the validity of the Jensen Model. After finding out the possible behavior of wake interactions for different wind directions, power calculations were performed for the same three cases. In order to perform the power calculations the wake interactions for different wind directions were taken into account. In case of platform turning it was assumed that power losses were caused both by wake interactions and in case of thrusters activation. The losses that would be caused by different thrust forces on the turbine blades were not included. The last study was performed to suggest different layouts. In the second case, Nacelle yawing and fixed platform, it was found out that nacelle yawing for most of the angles is not possible because it creates wake regions in front of the rotor area. It was decided to propose new turbine configurations on the platform which are tolerant to different nacelle yawing angles. The simulations were run without considering any constructions limitations, meaning that the availability of platform structure was not included. The study is ended by performing some probabilistic results for platform turning behavior.
77

Vision Sjöhem : Framtagning av förslagshandlingar för flytande bostäder / Urban Seasted : Development of concept drawings of floating residences

Heimbürger, Anna, Liljeroth, Pauline January 2014 (has links)
Stockholm lider idag av omfattande bostadsbrist och ständigt ökande befolkningsmängd. För att möta detta ökande behov av bostäder i Stockholm finns en nödvändighet i att utforska nya vägar till att åstadkomma detta. Här finns en unik möjlighet till en förtätning av staden genom att utnyttja Stockholms stora vattenarealer för att bygga flytande bostäder. Som alternativ till den traditionella byggkonsten ämnar examensarbetet till att demonstrera de kvaliteter som finns med att bo på vatten genom att utforma ett attraktivt bostadsområde med flytande konstruktion. Projektet illustreras i det tidigare hamnområdet vid Liljeholmskajen i Årstadals hamn, Stockholm. För att åstadkomma detta utförs fallstudier på olika typer av flytande konstruktioner som finns på den svenska marknaden för att fastställa de bästa konstruktionslösningarna som leder till färdiga förslagshandlingar. Resultatet visar att ett flytande bostadsområde är genomförbart med dagens teknik som ett sätt att förtäta staden. Vidare utredningar måste dock göras för att i framtiden legalisera och förenkla lagstiftningen kring denna typ av boende. / Present day, Stockholm suffers from a significant lack of dwellings and the population in the county is ever increasing. To meet this escalating demand for residences it is essential to explore new paths of accomplishing this. Here lies a unique opportunity for densification of the city by taking advantage of Stockholm’s grand water areal to build floating residences. This essay aims to demonstrate an alternative to the traditional arts of building construction by presenting the qualities of living on water in a proposition for a floating residential area. The project is displayed as placed in an old industrial port - Liljeholmskajen - in Årstadal, Stockholm. To achieve this, case studies are made on different types of floating constructions on the Swedish market to establish the best constructional solutions, which have led to complete concept drawings. The result illustrates that a floating residential area is achievable with today’s technology as a method of dealing with the densification of cities. Further investigations are necessary to legalize and simplify the legislation of this type of living
78

THE POTENTIAL OF WATER - A CITY PLANNING PROJECT EXPLORING THE POSSIBILITIES OF FLOATING STRUCTURES

Roth, Sherin January 2021 (has links)
This project investigates the possibilities of building on water as a way to add valuable land to dense cities. By utilizing floating structures, I have made a proposal for a new city district on the water outside of Fisksätra, a suburb located 30 minutes east of Stockholm. My ambition was to create a diverse and lively area with business and dwellings that cater to people in all stages of life. The proposal stretches along the western coast of Fisksätra creating a connection between the center of the suburb and a neighboring town as well as making that stretch of the coast accessible for the public. Increasing the access to the water and the coastline has been one of the main goals of the project and the proposal has been made with the ambition to open up the water for both the inhabitants of the new district and the rest of Fisksätra.
79

Hardware Modules for Safe Integer and Floating-Point Arithmetic

Ratan, Amrita January 2013 (has links)
No description available.
80

The control of an open-circuit, floating cup variable displacement pump

Achten, Peter, Eggenkamp, Sjoerd 02 May 2016 (has links) (PDF)
The floating cup principle is a general hydrostatic principle for both constant and variable displacement pumps and motors, as well as for hydraulic transformers. In this paper, the focus will be entirely on the control of the displacement of the variable 28 cc Floating Cup pump (FCVP28). The floating cup principle features two opposed swash plates, for which both angular positions need to be controlled in order to cover the entire range from zero to full displacement. The results of both extended numerical analysis as well as simplified linearized models will be compared to test results on a 28 cc FCVP. Special emphasis will be on the dynamic behaviour of the displacement control.

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