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858 Uppsatser om Coefficient of heat transmission - Sida 29 av 58
Analys och förbättringsförslag för riktkopplardesign
Ericsson develops a new stripline directional coupler. Its design is described in appendix B and differs from the directional couplers Ericsson uses in current products. The new directional coupler will be used for transmission power measurement in future UMTS 3G base stations.The most important parts of directional coupler theory are presented. It is necessary to study this theory to understand how the coupler works and how it should be designed to get good performance.Optimal directional coupler termination component values to get high directivity and broad directivity bandwidth have been investigated.The trim screws trim ranges have been studied.A simple analysis of serial production performance when termination component tolerances are taken into consideration has been done.The resistance components reactive (inductive/capacitive) characteristics at 2.14 GHz have been analyzed.The directivity performance limitations of the directional coupler, when Ericsson?s band pass filter is connected, are investigated.Design changes leading to better performance are proposed.
Understensho?jdens framtida utveckling : ett arbete om energieffektiviseringar i ekobyn samt uppgraderingar av dess energisystem utifra?n ett ha?llbart perspektiv
Understensho?jden is Stockholm's largest eco-village which was built in the early 1990s with the vision of enabling ecological living for people. However the ecovillage is no longer considered as environmentally friendly because of its relatively high energy consumption, and non-updated energy system. The purpose of this study is therefore to investigate how Understensho?jden should reduce their energy consumption and upgrade its energy system by using Blower-Door, IR-camera and Design Builder.
Optical and Structural Properties of CuxS Quantum Dots Concerning H2O/Ethanol Solvent Ratio
Nanotechnology, one of the most interesting sciences today will no doubt have an enourmous impact on tomorrow's society and industry. One of the most interesting nanomaterial that has been discovered is the semiconductor quantum dot (QD). This material shows interesting novel properties such as a size-dependent band gap, which is an effect caused by the quantum confinement effect in all three dimensions. Due to this phenomenon the absorption spectrum can be tuned to the desired value by adjusting the size of the QD.This thesis aims to investigate how the solvent ratio of H2O/Ethanol affects the optical and structural properties of copper sulfide QDs manufactured in a chemical synthesis way using modern microwave heating. The process of manufacturing QDs using chemical synthesis often involve a capping-agent to prevent the QDs from agglomerate into bigger structures.
Livscykelanalys av flerbostadshus ? energieffektiviseringsåtgärder för minskade koldioxidutsläpp
The importance of energy- and environmental issues has increased, and the work towards reducing carbon dioxide emissions plays a major part. The European Union has set up goals for the membership countries to work towards this to happen. The carbon dioxide emissions in Sweden have been reduced the last few years, but there is still a lot to do. About 30 per cent of Sweden?s carbon dioxide emissions generate from energy usage related to housing, this is why the housing sector is of interest to examine.
Dynamisk modellering av VSC-HVDC : En statisk och dynamisk modelldesign o?ver VSC-HVDC fo?r implementering i ARISTO
This thesis treats the subject of a complete steady state and dynamic model of the VSC-HVDC covering both the AC and DC system-side of the converter. The topology of the model is recreated after the scheduled transmission line in the south of Sweden, called SydVa?stla?nken. The topology covers both a simple two terminal connection as well as a multi-terminal one. This model is to be implemented in the power system simulation program ARISTO.
Image follows structure
Background: The business market today is characterized by tough competition amongst the competitors to capture consumers? interest and money. One marketing tool companies can use to achieve this is the company?s image. The customer buys not only a product, but also the image that the company or the product is associated with.
Underlag för bedömning av energibrunnar inom vattenskyddsområde
Denna rapport beskriver arbetet med utvecklingen av en ny modell för kaplanturbiner. Utvecklingen bygger på två kopplade differentialekvationer som under arbetets gång anpassats och implementerats i turbinmodellen.Modellen beskriver hur vattenflöde och turbinmoment påverkas av avvikelsen från den optimala kombineringskurvan för vinklarna på turbinens ledskena och löphjul, och är anpassad för ett referensaggregat med tillgängliga provdata. Även övriga enheter i vattenkraftaggregatet modelleras och sätts samman med frekvensregulator och elnät för att simulera aggregatets reglerstabilitet i önätsdrift.Verifieringen av turbinmodellen sker genom försök att återskapa de befintliga verkningsgradskurvorna med hjälp av modellen. Resultatet visar en god följning av de verkliga kurvformerna, dock med något lägre maximal verkningsgrad.Verifieringen av önätmodellen sker genom att prova stabiliteten i nätfrekvens och turbineffekt vid stegpålastningar. Resultatet ger en stabilare reglerstabilitet än i verkligheten, men uppfyller ändå förväntningarna på en fungerande modell.This report describes the development of a new kaplan turbine model.
Smarta lokala energisystem, Vision-Teknik-Tillämpning
The energy sector is facing an impending paradigm shift. Today?s technology enables the end-user to generate their own energy locally at home. Furthermore, recently developed storage technologies make it possible to balance energy demand with stored energy and integrate district heating with the local power grid. This means that in the future heat and electric power will interact and energy flows is converted over energy boundaries.
Effektmätning i pump
The interest for power and energy measurement has greatly raised with todays increasing electricity prices and enviromental awareness. In the search for energy efficient solutions, the measurements are more complex due to increasing of non linear components. Harmonics and non sinusoidal voltages put high demands on sampling and filtering. Meanwhile, the price must be controlled so the customer still will find it interesting to invest in smaller plants. ITT W&WW asks for a robust, heat resistant power meter with compact dimensions to allow mounting inside the casing of a pump.
Diagnosis and molecular epidemiology of bovine rotavirus and coronarvirus in Brazil
Rotavirus and coronavirus are the two most common viral causes of neonatal calf diarrhea and their presence causes a lot of economic damage to the farmers as well as suffering to the animal. By getting better knowledge about the viruses we may help in tracing transmission and in producing new vaccines. This paper served to study the molecular epidemiology of rotavirus and coronavirus in fecal samples collected from two different farms in the state of São Paulo, Brazil. These samples have been studied with focus on the gene VP4, VP7, NSP4 in rotavirus and the gene S1 in coronavirus. From the first farm the screening PCR showed that 12/48 samples were positive for rotavirus and 4/48 positive for coronavirus.
Utvärdering av energieffektiviseringsåtgärder på Bokelundskolan i Växjö
The purpose with this report is to examine how the implemented energy efficiency measures on Bokelundskolan in Växjö have had impact on the energy use. The measures which have been implemented are, new ventilation system, new heating system, optimized adjustment of the heating system, new windows with U-value 1.2 and lower window height, insulation under windows and in the crawl space. The school's energy use before and after rebuilding has been calculated with the calculation program, Vip-Energy 1.5.5.Calculations of energy use for the school with windows on U-value, 0.9 and 0.7 have also been done. The replacement of windows has been studied from a cost perspective. The conclusion is that the exchange of heat and ventilation system was the biggest contributor to reduced energy use on Bokelundskolan.
Design och implementation av konfigurationsverktyg för funktionsblock
Abstract In high voltage substations there is an increasing demand for computerized equipment, and automation of operation and supervision. The future primary equipment will provide the possibility to collect more information and to provide better control for improved effectiveness. Since ABB has got a large customer target, each product must be custom made to fulfil the customers (often from different countries) demands. Later these products will be configured by engineers who may not be familiar with the tools used at ABB. This is a very expensive and time consuming.
Självbiografins position på det litterära fältet
The purpose of this paper is to study the image of Strindberg that is conveyed in four different textbooks for the upper secondary school. How do the teaching authors choose to portray Strindberg? Do they focus on any one particular aspect of his writing? Adjacent to this a subsidiary aim is to see if teaching authors highlight the fictional nature of Strindberg?s works or choose to encourage a biographical interpretation. The work consists of a study of four literary history textbooks in the subject of Swedish for the upper secondary school, from 2000 to 2012. In the selected material the sections focusing on Strindberg and his writings are closely read and critically analysed.
Etiologi för sporadisk hepatit E i industriländer
Det finns många olika typer av bromerade flamskyddsmedel. De är alla stabila i miljön men graden av toxicitet och bioackumulering varierar. Att bromerade flamskyddsmedel är
endokrinstörande är känt men min hypotes är att de även är neurotoxiska och att de kan orsaka neurologiska störningar hos människa.
Människor exponeras för bromerade flamskyddsmedel via damm och föda. Barn och foster som är känsligare än vuxna kan även exponeras via modersmjölk respektive placenta. Barn
har högre serumkoncentrationer av bromerade flamskyddsmedel än vuxna.
Solenergi på Kvarnholmen
In recent years it has become more and more evident that man has contributed to much of the climate changes that have taken place during the last century. A major challenge today is to reduce emissions and energy usage at the same time as the global population is growing. To contribute to a better environment, Stockholms Stad has set at target of becoming fossil fuel free by the year of 2050. The construction of new districts is done with this goal in mind; energy efficiency and renewable energy sources are examples of methods to achieve this.Solar energy is considered to be a sustainable energy source and the most common techniques to harvest solar energy in Sweden are solar cells and solar collectors which produce electricity and heat respectively. This report aims to investigate whether an investment in any of these systems would prove to be economically beneficial at Kvarnholmen, a district under construction in eastern Nacka, Stockholm.Since the finished blueprints only cover a small portion of Kvarnholmen, the report examines the possibilities for a house where construction has already begun, Nya Kvarnen.