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1226 Uppsatser om Heat loss - Sida 31 av 82
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.
Differences of progressive retinal atrophy in dogs
A group of diseases that affect the dog?s sight is progressive retinal atrophy (PRA) a disease that means that the photoreceptors in the retina of the eye either not develop normally or undergo degeneration and thereby causes vision loss and blindness. The disease affects many different breeds and is inherited. What have been shown is that it is different genes that had become mutated in the different breeds, this conclude that despite similar clinical symptoms, the underlying reason could be different. Also the genes that are mutated in dogs and give rise to diseases also exists in humans.
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.
Förekomst & kostnad av kapsprickor i stormaskadad skog
The aim for this study where to investigate the frequency of cutting cracks in saw timber harvested in the storm-damaged forests in regions where the storms Hilde and Ivar hit. The idea for this work came from one of the region?s biggest actors, SCA Skog and Jämtlands district. The purpose where to find out how big proportion of the saw timber that contains cutting cracks, their financial cost in lost wood value and also give advice and suggestions on how to work against the frequency of cutting cracks.
For the field-study some guidelines where used to make sure that the samples were taken under the same conditions, they were:
? The field-study must be performed under harvesting of storm-felled forest, which are horizontal/inclined trunks.
? The averaged sized tree will make it possible to harvest saw timber.
? The trunks can?t be root cut.
A methodology called in Swedish ?Trissmetoden? was used because it is the most frequent used methodology in earlier performed studies and the only one that can be used I field.
Under the field-study data were collected from 570 saw timber logs, 30 logs from each one of the tested harvesters.
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.
Åtkomst till affärssystem i mobila enheter - För- och nackdelar
The purpose of this study was to investigate the reason behind thedecision by a company regarding the desire to use mobile access to theirERP-system and to discover whether this will involve any loss offunctionally in comparison to using the ERP-system on a computer atthe office. In addition, the pros and cons involved in using mobiledevices for accessing the ERP-system will also be examined. Semistructured telephone interviews were conducted with companies whicheither used or did not use mobile devices in relation to their work. Atelephone interview was also conducted with a consultant who isworking with the implementation of ERP-systems and mobile solutions.The survey showed that companies with staff working in the field assellers, service personnel and construction workers want to gain directaccess to their ERP-system so as to be able to act directly and takedecisions, to have the ability to provide more efficient order processingand to send out invoices more quickly. Those companies which have notopted to use mobile devices at work within this field are those whichare unsure of the connection to the Internet and the capacities availablewithin cellphones.
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.
Utveckling av dataanalysprogram för Opcon Powerbox
Opcon Powerbox is a product developed by Opcon together with the underlying company SRM (Svenska Rotor Maskiner) where surplus heat from the industry is used through an Organic Rankine Cycle (ORC)?process to produce electricity. An ORC-process is a thermodynamic circle process in which a refrigerant is used as the working fluid. The refrigerant makes it possible for the circle process to operate at lower temperatures than the conventional Rankine process.In this master?s thesis a data analysis software for the Opcon Powerbox has been developed in which measurement data is retrieved and handled from the Opcon Powerbox.
En studie av ett grupporganiserat lärande
The sun is an endless energy source and the heat it produces can be used to heatup our homes. This technology is relatively old and was introduced in the late70-s. There are two kinds of solar collectors that are most frequently used todayand these are plain solar collectors and vacuum solar collectors. The plain solarcollectors are the once that are used the most but the vacuum solar collectorshave increased more as a percentage the last couple of years.The biggest question asked regarding an investment in solar heating is if theplant is economically profitable. This question has no direct answer because itis dependent on a couple of prerequisites.
Kunskapssyn och behov av IKT - verktyg
The sun is an endless energy source and the heat it produces can be used to heatup our homes. This technology is relatively old and was introduced in the late70-s. There are two kinds of solar collectors that are most frequently used todayand these are plain solar collectors and vacuum solar collectors. The plain solarcollectors are the once that are used the most but the vacuum solar collectorshave increased more as a percentage the last couple of years.The biggest question asked regarding an investment in solar heating is if theplant is economically profitable. This question has no direct answer because itis dependent on a couple of prerequisites.
Påverkar euron resultatet av stabiliseringspolitiken? : En studie av stabiliseringspolitikens utfall i de nordiska länderna sedan eurons tillkomst, och av betydelsen av en nationell penningpolitik.
This paper discusses whether the main argument for European countries to stay out of the euro, i.e. the loss in stability from not having a national monetary policy that can be used for stabilization purposes, is still valid ten years after the introduction of the single currency. We analyse the stabilization performances of four largely comparable Nordic countries that have all chosen different levels of European economic integration. In retrospect, the so-called ?stabilization policy argument? seems surprisingly weak.
GALS,Design och simulering för FPGA med VHDL
Heat, clock scew and frequency optimization are some of the problems a semiconductor designer must face. By splitting a synchrounous block into multiple pieces which comunicates asynchronously with eachother and provide them with independent clocks, these problems may be reduced. GALS (Global Asynchronous Local Synchronous) is a wrapper that wraps a synchronous block and provides it with a clock. Multiple GALS-elements will make the whole system. The clockfrequency may be independently adjusted between each block.
Sura Gamla Kyrka : analys av patologiska och skeletala förändringar hos sju individer
Seven individuals from Surahammar in Västmanland Sweden are analyzed for the appearance of pathological and skeletal changes. The graves, all from within the walls of a fourteenth century church, are dated from the Viking age to late eighteenth century. The aim of this scientific essay is to find pathological conditions by doing an osteological analyze, x-ray analysis, an osteoporosis measurement and letting orthopedists assess the individuals. The aim is also to say something about the individuals? general health and how they experience the changes they have in the skeleton.
Deaktivering av metanisering katalysatorer
A titania-supported nickel catalyst was prepared and tested in methanation in order to evaluate its catalytic properties (activity, selectivity and specially, activity loss), and compare it with an alumina-supported nickel catalyst.The titania-supported catalyst did not only show higher stability than alumina, but also presented a different cause of deactivation, carbon formation. In addition, a kinetic model was obtained for the titania-supported catalyst, and a study of the effect of different operating conditions (temperature, composition and partial pressures of synthesis gas and water) on the deactivation rate and carbon formation of this catalyst was performed.