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2603 Uppsatser om Constant current regulator - Sida 8 av 174

Effekter av tidiga reflektioner vid musikreproduktion

In this project the focus has been on the system for recombination at Oskarshamn 2. The recombining systems have on several occasions switched paths due to low pressure before the last ejector that?s feeding the recombiner. Of the mentioned reason, events and several measuring points have been analyzed in this report since the installation of the recombining systems.In order to prove theories and demonstrate what may be the cause of this problem, we used heat balance calculations by the program Probera. Using the program, we can demonstrate that the catalytic process does not reach the desired temperature with the amount of combustible substance.

Strömkontroll till aktiva magnetlager med noggrann och störningsreducerad strömmätning

There is always a need for more effective ways to store energy in order to reduce the human impact on the environment. One step on the way can be the use of flywheels as kinetic energy storage devices. Low frictional losses are essential for a flywheel to be effective. To minimize these losses active magnetic bearings (AMB) can be used to keep the shaft centered instead of the more conventional ball-bearings. AMBs use actuators and a fast control system that needs correct and noise-free measurement data of the shaft position and the current in the actuators to work properly.This thesis explains the process of constructing power electronics and a current measurement system for active magnetic bearings (AMB).

Klassiska konflikter i en ny debatt - Analys av idéerna i debatten kring bildandet av ett feministiskt parti i form av Feministiskt initiativ

Every now and then new political ideas appear which creates debate. A current example of political debate is the one which concerns the creation of a feminist political party in Sweden -Feministiskt initiativ. Apparent in the current debate is that there are two existing conflicts of ideas present. The liberal thought of politics of ideas stands against feminism's demand for presence in the political life. And the other, the conflict which concerns the question of where a line between the public and the private spheres should be drawn.

Analytiker och riktkurser: - Varför bry sig?

The purpose of this master thesis is to evaluate how the current share price and market consensus affect security analysts target price and if an investor should pay any attention to it. Empirical data is primarily collected from qualitative interviews with ten security analysts but also from a quantitative e-mail survey. Our main finding is that security analysts are indeed affected by each others earnings forecasts as well as the current share price. This is not strange, it is in several aspects rational. Security analysts has often nothing to gain by standing out too much and not either by spending too much time trying to create their own opinions due to lack of time or the complexity of what is analyzed.

Syntes och egenskapskarakterisering av volframoxid framställd med magnetronsputtring

The system tungsten-oxygen has potential of being suitable for decorative coatings since ceramic coatings are often hard and wear resistant, and since modulations in oxygen content or incorporation of small ions could give bright colours. The aim of this report was to investigate the relationship between process parameters and  the properties of the films, with the wear resistance being of special interest.Samples with tungsten to oxygen ratios in the range of 100:0 to 25:75 at% were made using reactive sputter deposition, either with constant gas flow, or gas flow controlled by optical emission of the plasma. The hysteresis of the system, which means that a certain gas flow will cause different pressure and/or target voltage depending on in what way the flow is reached, makes it interesting to control the process where the system makes the steep change from metallic tungsten to ceramic tungsten oxide. This is difficult and thus requires precise control equipment.The samples were analysed using X-ray diffraction, X-ray photoelectron spectroscopy and an empirical wear test suitable for small components like cell phone cover for example, in order to characterize the structure, composition and wear resistance of the coatings. The results could be divided into three groups: (I) tungsten-like, with very low oxygen content; (II) mixed phase and (III) tungsten oxide like, with oxygen content close to 75 at%.

Dokumenthantering i företag och organisationer: En fallstudie på Volvo Cars i Uddevalla

The aim of this thesis is to map the current internal information flow at Volvo Uddevalla, to detect obstacles in the flow and to find out how these obstacles can be avoided. The aim is also to describe how a corporation, in this particular case Volvo Uddevalla, creates knowledge and use information. The study is performed in order to create a base for the coming implementation of a new information standard. The method used is conducting an information audit investigating the current management of documentation according to the changes that have to be made to carry out the claims from the standard. The investigation is made by way of interviews with 16 of the employees at Volvo Uddevalla.

Solenergisystem i Hammarby Sjöstad

Problems with the current energy system, which partially relies on non-renewable fuels, are increasingly recognized. Emissions of greenhouse gases from fossil fuels may speed up global warming, which in turn leads to a number of negative consequences. Nuclear energy is risky and relies on consumption of a scarce resource. This leads to a demand of renewable energy that is also economically feasible. One possible renewable source of energy is solar energy.

Serietecknaryrket

Information technology and globalization has led to an increasing competition and service production has been more and more independent of locations. This has made a market of outsourced telephone costumer service possible. Due to high establishment the market has been saturated and with that price has sunk. Customer companies have the last few years got more negative to outsourcing of their telephone customer service as they through operating the customer service internally want to get closer to their customers.In the empirical study the writers try to figure out which companies the callcenters should try to aim towards to get long and profitable cooperation. This will be done through deducing guiding principles from theories about how different factors around companies costumer service should look like.

Modellering och simulering av det evaporativa bränslesystemet i en personbil

This thesis work has been performed at the department of diagnosis and dependability at Volvo Car Company, Torslanda. The background of this project is based on interest in ascertaining how different factors possibly can affect a diagnosis method, which has been developed to find leaks in the fuel tank and evaporation system. According to the OBD II requirements leaks with an orifice diameter larger or equal to 0,5 mm, must be detected. The idea of the diagnosis method is to create an over pressure in the system with an air-pump. The current through the pump is measured and correlates to the power consumed by the pump.

Automatisk trimning av drivsystemreglering från MATLAB

This master thesis covers the development of an automatic tuning process for the existing speed controller for drive systems. The drive systems are resonant two-mass systems where a motor is used to drive a load connected by a shaft. The developed method relies heavily on system identification and the construction of a complete mechanical model of the process. With this approach, the common problem with poor load speed control that derives from measuring only the motor speed can be addressed and solved for a majority of such processes.The automatic tuning method has along with general test functions been implemented in a complete tool for automatic tuning, testing and performance evaluation and reporting for drive systems..

Modellering av aktivt stötdämpningssystem med MR-dämpare

I denna rapport redovisas modellbyggande av ett aktivt stötdämpningssystem till en formulabil. Stötdämparna som har använts i modelleringsarbetet är av MR-teknologi (Magneto Rheological). Dämpningskaraktäristik för MR-dämparna har tagits fram genom tester samt databehandling med mjukvaran Matlab. Genom användandet av modellerings- och simuleringsprogrammet Dymola (Dynamic Modelling Laboratory) med dess olika komponentbibliotek har flera delmodeller skapats för stötdämpningssystemet. Dessa modeller är baserade på fysikaliska relationer och de sätts sedan samman till en hel modell av systemet.

System 348 - Rekombinator : Analys av reglerproblematik vid O2

In this project the focus has been on the system for recombination at Oskarshamn 2. The recombining systems have on several occasions switched paths due to low pressure before the last ejector that?s feeding the recombiner. Of the mentioned reason, events and several measuring points have been analyzed in this report since the installation of the recombining systems.In order to prove theories and demonstrate what may be the cause of this problem, we used heat balance calculations by the program Probera. Using the program, we can demonstrate that the catalytic process does not reach the desired temperature with the amount of combustible substance.

Vägledningsmetoder? Ja, tack! Nej, tack! : Om användninga av vägledningsmetoder av yrkesverksamma studie- och yrkesvägledare

The overall aim of this study is to achieve the increased knowledge of the use of the counselling methods in the student counsellors' work and to find the possibilities for development. Two questions are used as guidelines:Which counselling methods do student counsellors use in their work in schools?How can the current education for the student counsellors be supplemented?The analysis of the interviews with six counsellors in Stockholm's administrative province showed that even uneducated counsellors use the same counselling methods as the educated ones. All these methods which are used remind of the known counselling methods that are the part of the current education for the student counsellors.In general counsellors experienced that the education for the counsellors should be supplemented within the field children with special needs and that conversation's methodology is the essence of the counselling work..

Light pollution : consequences and sustainable lighting design

Light has always fascinated humans but ever since the invention of the first light bulb, the use of artificial lighting has accelerated dramatically. Darkness has never been as rare as today and the overuse of lighting has created a new phenomenon called light pollution. Most living beings are biologically dependent on the recurrent twenty-four-hour rhythm of light and darkness, called the circadian cycle. Human beings are evolutionary developed after this circadian rhythm and the effects of constant artificial light is yet unknown. Scientists fear the consequences of constant lighting and what it means physically, mentally and philosophically for the human species.

Utveckling av högspänningskontakt

This report describes the development of a high-voltage connector at the request of Scandinova Systems AB in Uppsala. The development process is described from the making of a customer demand specification, to the making of drawings for the manufacturing of prototypes. Scandinova develops high-voltage modulators, hence the need for connectors that can handle very large power pulses. Their current connector has several weaknesses that may cause the connector to melt or catch fire. The development began with a number of studies that included the modulator structure and the current connector structure and functions.

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