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492 Uppsatser om Mathematical programming - Sida 32 av 33

Latent värmelagring i vattenburet uppvärmningssystem med elpanna för byggnadsapplikationer

Latent heat storage is a way to store thermal energy when a phase change material undergoes a phase change. The advantage of latent heat storage is the capability to store more energy per mass unit than other heat storage methods. The most commonly used phase change in latent heat storage is the transition between solid and liquid. Phase change materials can be divided into organics, inorganics and eutectics.In the Nordic electricity market the price of electricity is set every hour by Nordpool spot, which leads to price fluctuations because of changes in demand. The main goal of this report is to create a latent heat storage system in a single-family home and investigate the possibility to save money by charging the latent heat storage system when the price of electricity is low, and discharge when the price is high.The thermodynamic model consisted of a ?tube-in-tube? heat exchanger with phase change material in the outer tube and water as the heat transfer fluid in the inner tube.

En flashestimator för den privata konsumtionen i Sverige med hjälpvariablerna HIP och detaljhandeln ? En tidsserieanalys med hjälp av statistikprogrammet TRAMO

In this essay we aim at finding an appropriate flash estimator of the quarterly Swedish private consumption (PK). With the aid of the statistics program TRAMO we study if monthly data from the consumer survey (HIP) and retail industry (DH) can be used in a transfer function model (TFM) to forecast PK. In the work of assessing the state of the market and the business trend, fast information from the national accounts is needed for making decisions for the economic politics in Sweden. A way to speed up the information process is to use leading economic indicators to asses this development. Another way to get information faster is to use a flash estimate.

Mikrosensorer i nätverk

The purpose of this thesis is to investigate the possibility to make small, cheap and ultra low power sensor platforms, connected in wireless networks for monitoring of home and industrial environments. The concept is based on ideas from our supervisor, Jerry Lindblom. The developed system consists of a generic platform for different sensors, a receiver and software. A GPRS module from RO Rollytech AB and a database from Gema Industri AB have been modified and used to demonstrate an example of a complete system. To the platform, it is possible to connect any resistive sensor and any sensor that can act as a switch.

Investering i spannmålstorkning och lagring på gårdsnivå : en jämförelse av ett silotorksystem med omrörare och en konventionell anläggning

The current situation for Swedish grain farmers facing a situation with decreasing profitability makes it necessary for the farmers to find ways of increasing the margins in their grain growing. Decreasing profitabilities along with Lantmännens closing of grain elevators contribute to the necessity for farmers to invest in grain storing and drying at the farm. By investing in capacity for drying and storage of grain on the farm it is possible to recieve a higher price on the grain sold due to the possibility to sell when the price is higher compared to the harvesting season. An investment in grain drying and storage with a relatively low investment cost that recently has appeared on the Swedish market is the grain stir drying system. This study contains a comparison of an investment in a grain stir drying system where the grain is dried and stored in the same silo and a conventional drying and storage system.

Framtagning av en förebyggande åtgärd mot kriminalitet vid lastbilstransporter

Boberg at Scania CV AB. The purpose was to investigate the technical and customer oriented possibilities for the development of a transport security measure against cargo crime, which is a growing problem in Europe. The main goal was to develop a concept that is possible to implement in the Scania CV AB Fleet Management System. Another goal was to develop a security model that will be used as a tool during Scania CV AB?s future development projects of transport security concepts.The work was divided into three main parts: a background study, handling cargo crime, transport security Scania CV AB trucks and market analysis, a stakeholder investigation including a questionnaire and interviews, and a concept development session.

Högtempererat borrhålslager för fjärrvärme

The district heating load is seasonally dependent, with a low load during periods of high ambient temperature. Thermal energy storage (TES) has the potential to shift heating loads from winter to summer, thus reducing cost and environmental impact of District Heat production. In this study, a concept of high temperature borehole thermal energy storage (HT-BTES) together with a pellet heating plant for temperature boost, is presented and evaluated by its technical limitations, its ability to supply heat, its function within the district heating system, as well as its environmental impact and economic viability in Gothenburg, Sweden, a city with access to high quantities of waste heat.The concept has proven potentially environmentally friendly and potentially profitable if its design is balanced to achieve a good enough supply temperature from the HT-BTES. The size of the heat storage, the distance between boreholes and low borehole thermal resistance are key parameters to achieve high temperature. Profitability increases if a location with lower temperature demand, as well as risk of future shortage of supply, can be met.

Optimering av blandning och lagerhållning av avfallsbränsle : Optimering av avfallsbränsleblandning och lagerhållning av importerat avfallsbränsle vid Vattenfalls fjärrvärmeverk i Uppsala

Fjärrvärmebranschen i Sverige har sedan mitten av 1990-talet varit i en stagnationsfas, där mängden producerad och förbrukad energi i stort sett varit konstant, trots stora investeringar i fjärrvärmenätet. Samtidigt har den höga andelen återvinning gjort att det råder brist på avfallsbränsle till energiåtervinning i Sverige. I kombination med hög konkurrens om avfallsbränslet har detta medfört att aktörerna på marknaden tvingats se sig om efter nya vägar att tillfredsställa behovet av bränsle, vilket lett till att det idag importeras stora mängder avfall för energiåtervinning från utlandet. Vid Vattenfalls fjärrvärmeverk i Uppsala har det mellan åren 2006-2013 återvunnits i snitt drygt 360 000 ton avfall per år. En stor del av detta hämtas in från lokala kunder, både kommuner och privata aktörer, men man har på senare tid även behövt börja importera avfall för att tillfredsställa energibehovet.

Utveckling och tillämpning av en GIS-baserad hydrologisk modell

A distributed hydrological rainfall-runoff model has been developed using a GIS integrated with a dynamic programming module (PCRaster). The model has been developed within the framework of the EU-project TWINBAS at IVL Swedish Environmental Research Institute, and is intended for use in WATSHMAN ? a tool for watershed management developed at IVL. The model simulates runoff from a catchment based on daily mean values of temperature and precipitation. The GIS input data consist of maps with soil type, land-use, lakes, rivers and a digital elevation model.

Effekter av kön, ålder och region på sjukpenningen i Sverige - en variansanalys

According to TCO (The Swedish Confederation for Professional Employees) the worst threat to the Swedish welfare is that so many people because of bad health and unemployment are not a part of the labour force. If Sweden could make the number of people with health and unemployment problems half the size as today, the GDP would increase with more than five percent. In real money this means 110 billion Swedish kronor a year. According to SCB (Statistics Sweden) the difference between women?s and men?s absence owing to illness should be investigated more closely in order to get at better understanding of the problem.

Vidden av kommunikationsförmågan i matematikundervisningen : En studie av problemlösningsmetoder med elever i år 3

Bakgrund: I grundskolans läroplan synliggörs tydligt att eleven i matematikundervisningen skall utveckla olika förmågor och att dessa är centrala. En av dessa är kommunikationsförmågan, som är särskilt betydelsefull genom att den sammanlänkas till alla de övriga, såsom de som gäller representation, resonemang och problemlösning. Av denna anledning har kommunikationsförmågan i matematik och medvetenheten kring och utvecklingen av denna hos lärare och elever undersökts i denna studie. En grundförutsättning är att individuell färdighetsträning i lärobok är otillräckligt. Elever bör tidigt få möjlighet till exempelvis arbete i grupp med ett matematiskt problem, då de i tal och skrift kommunicerar matematiska begrepp och metoder.

Stress test methods : a potential approach to hurry up shelf-life tests on oat products

The aim of this Master?s thesis was to find out more about the delimiting quality- and shelf-life parameters over time for liquid oat-based products. According to that, to present applicable subjective and objective shelf-life test approaches at accelerated conditions. The study aimed to gain a deeper knowledge concerning the general and accepted way of performing accelerated storage tests. This study focused especially on products, which suffer from quality failure caused by oxidation, such as liquid oat-based products.

Solvenskrav och riskhantering enligt Solvens II : Implementering av de nya riskbaserade solvensreglerna på ett skadeförsäkringsbolag

The insurance industryis challengedby major changesthrough internationalizationand thusgrowingcompetitionwithmore optionsand greater availabilityfor customers.Solvency II, a new regulatoryframework and anew standard forinsurance companies,is therefore implemented in a steptowardsa more competitive Europeaninsurancemarket. Solvency II will result in extensive structural changes for many insurance companies. Newstandards andinternal models must also be implemented by the companies. Solvency IIhasa tightening effect on thesolvency capital requirements forinsurance companies. At the same time it also leads tomajor changesandincreased demandon risk management andinternal control, alongside with demands fordisclosure of informationto the market.

Prestation, intresse, engagemang, uppskattning : Skillnader i upplevelse av en virtuell lärmiljö mellan matematiskt hög- och lågpresterande elever

Digitala läromedel blir ett vanligare inslag i skolgången då ny teknologi erbjuder tidigare okända pedagogiska möjligheter. Denna uppsats undersöker hur elever som använder ett digitalt läromedel i form av en virtuell lärmiljö för matematiklärande upplever denna lärmiljö. Dessutom undersöks elevernas prestation i lärmiljöns matematiska uppgifter. Skillnader mellan elever i olika årskurser samt elever som är matematiskt låg- eller högpresterande studeras. Matematisk prestation beskrivs utifrån Goods (1981) passivitetsmodell som innebär att lågpresterande elever är mindre risktagande i klassrumsmiljön.Elevernas upplevelse av digitala läromedel studerades i en virtuell lärmiljö bestående av två moduler, en spelmodul och en modul för skriven dialog.

Optimalt råvarulager för biobränsleföretaget :

This report was written as a final thesis within the Department of forest economics at the Swedish University of Agricultural Sciences as a completion of the M.SC Forestry programme. The aim of this study was to create a model that, with respect to given stock levels, temperature, fuel usage and fuel price, would identify the optimal levels for purchase of bio fuels, optimal levels of incineration of bio fuels and the sum of the present values of all costs. The model would be applicable for a larger district heating plant. Data regarding temperature were received from SMHI. Information considering fuel prices was taken from the Swedish Forest Agency and the facts about fuel usage were collected from a large district heating plant, located in the southwest of Sweden. For the temperature, a sinus curve was adapted to describe the temperature over a year.

Gårdsbaserade system för spannmålshantering i den framtida Lantmännenorganisationen :

The Swedish cooperative Lantmännen Ekonomiska Förening has initiated a project labelled "Operation Blåljus" that includes an extensive program for closing down elevators. The number of elevators will be reduced from 92 to approximately 15 after harvest of 2007. The objective of Blåljus is to increase the price of grain with 10 öre/kg. A project has been initiated at the Lantmännen Grain division where the purpose is to provide the farmers with support in their decisions and practical advice how they can load a 35 ton grain truck on 30 minutes. The result from the project will serve as a support system to the farmer in his ambition to achieve cost efficient systems to load a truck with grain on the farm.

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