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  • 251.
    Johansson, Erik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Parametric study of a wastewater heat recovery system for buildings2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Global efforts makes buildings successively more energy efficient. This results in that the percentage of the total energy in the building that is lost to the sewage system, in the form of hot water, is increasing. The characteristics of the wastewater originating from the urban water cycle makes it an attractive heat source which is relatively unexploited. Wastewater heat recovery (WWHR) systems is a group of systems designed to reduce a buildings use of external energy sources by recovering the heat out of the wastewater before it is let out into the sewage.        

    The focus of this report is a parametric study performed on a WWHR system that utilises thermal storage tanks for accumulation of wastewater and a heat pump equipped with heat exchangers for the heat recovery. The studied variables are the amount of energy that the system is able to recover out of the wastewater and the seasonal average COP of the heat pump. The change of these two variables were analysed both as an affect of parameters dependent of system design and on consumption patterns of the residents of the building. The results showed that by properly designing the system the recovery degree can be increased by 31.5 percentage points reaching values above 90 % and the seasonal average COP can be increased by 13.5 % reaching values of 5.13. However, these two variables stands in contrast to each other were maximising one will reduce the other and it is proposed that it is important to take both into account when evaluating a WWHR system. It is also shown that the consumption related parameters have a relatively big effect on the system. The change in recovery degree as a result of these non-controllable parameter is 14 percentage points and the seasonal average COP changes with 4.2 %.        

    The system performance as a result of changing the U-value of the heat exchanger connecting the system to the domestic hot water circuit was also analysed. This showed an exponential relation between the U-value and delivered energy from the heat pump. The results showed that an increase of the U-value from 50 W/K to 6000 W/K increased the yearly energy supplied with 37.6 % but an increase from 1000 W/K to 6000 W/K increased the yearly supplied energy with less than 1 %. This result highlights the importance of properly dimensioning the heat exchanger.

  • 252.
    Johansson, Kristina
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektivisering av vattenkraftverk2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    On behalf of the company One Nordic AB and Staffan Lundström, this report study several energy-saving measures that can be done at hydroelectric power stations. One Nordic AB wanted three areas to be investigated further a: the processes to keep the floodgate free from ice, b: recycling heat from the electric transformer and c: energy-saving solutions for lightning. The report gives both calculating examples on energy consumption and shows how the saving solutions can be applied in reality.

    The result shows that every process that leads to a more energy efficient solution should start with a deeper analysis which takes the budget, needs and demands in considerations along with all the potential risks. Since many variables make it difficult to present a general best solution the report presents a few recommended solutions to all the three investigated areas.

  • 253.
    Johansson, Kristoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Solceller på flerbostadshus2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sweden has taken upon themselves several goals to reduce their carbon footprint and exchange fossil fuels for renewable energy sources; Solar power will play an important part in fulfilling these goals. Due to declining costs and a technology that is getting more efficient solar power has seen a rampart growth is system installation the last couple of years. However, often economic support schemes are necessary for making a PV-system profitable, especially in Sweden where the sun doesn’t shine as much. Electricity generation with the use of PV-systems on buildings can be unreliable because the sun might not shine when the building needs the electricity, and the opposite is also a problem where the sun is shining, but the building doesn’t need electricity.

    The main purpose of this of this study was to evaluate the possibilities of a PV-system on two large residential buildings located in Sweden, Umeå. The study was conducted by gathering data about the buildings through measurement, pictures and investigation. With the data acquired a total of five different PV-systems was dimensioned to be tested for performance. The software PVGIS was used to analyze the PV-system performance by making use of climate data to simulate the weather conditions in Sweden. Thereafter the PV-systems economical prerequisites were analyzed by calculating LCOE, payback, present value and IRR.

    The results show that there are possibilities to install PV-systems on the buildings, but if larger systems are to be installed it seems like a battery is needed. If two smaller PV-system of total 113 kWp is installed the study suggest that relatively high levels of power self-sufficiency can be achieved. This is believed to be caused by the very constant electricity loads in the buildings. The energy output per kWp of installed power reaches 775 kWh/kWp on the best roof surfaces and is drastically lowered on the worst surfaces. Such energy exchange is considered low. The economical investigation shows that PV-systems that can use a lot of the produced electricity directly in the building instead of selling it to the public powerline has more profitability.

  • 254.
    Johansson, Matthias
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Syntetlinor i Bergsspel2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Järnmalmen från LKAB:s gruva i Kiruna fraktas dagligen upp ovan jord i det så kallade bergsspelet. Bergsspelet består idag utav stålvajrar, vilket har sina nackdelar. Deras egenvikt gör att tiden för underhåll ökar och produktionen påverkas negativt.

     

    En förstudie har gjorts för att undersöka huruvida syntetiska linor kan ersätta stålvajrar. Men för att testa deras hållfasthet gällande styrka, utmattning och töjning måste en testrigg byggas. Med hjälp av information från förstudien som genomförts och genom CAD-modellering tas ett konstruktionsunderlag fram till denna testrigg.

     

     Enligt tidigare studier som genomförts kan linor av de syntetiska materialen aramid, High Modulus Polyethylene och Liquid Crystal Polymer ersätta stålvajrar. Av dessa är aramid mest lämplig eftersom de inte drabbas av krypning och de är även testade i tuffa förhållanden. Syntetiska linor väger bara 1/5 relativt stålvajrar och är lika starka vilket ger stora produktionsmässiga fördelar.

     

    Framtida tester i testriggen, som skall tillverkas enligt angivet konstruktionsunderlag, får svara på vilka linor som passar LKAB. Olika material klarar av gruvdammet olika bra och det kan även finnas kombinationer av olika material som kan vara särskilt lämpliga.

  • 255.
    Johansson Ström, Styrbjörn
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Slutväxelhus CV90: Förarbete gällande geometriändringar, materialbyte samt dimensionering av skruvförband.2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Skydd och rörlighet är två viktiga egenskaper hos ett stridsfordon. De är även två motstridiga mål, då ökat skydd ger ökad vikt, vilket minskar terrängframkomligheten. Detta arbete syftar framför allt till att minska vikten på fordonet, genom att minska slutväxelhusets vikt. I arbetet ingår även att undersöka möjliga vägar för att minska reparationskostnader och stilleståndstid genom att förändra infästningen av slutväxelhuset, så att denna ej sliter sönder skrovet vid kollision.  För att minska slutväxelhusets vikt, kommer möjliga geometriändringar och materialbyte från gjutstål till segjärn studeras. Vidare kommer rapporten även undersöka möjligheten att införa en brytpinne i systemet, med syfte att försvaga slutväxelhusets fastsättning. För att detta skall vara möjligt kommer de aktuella lastfallen analyseras. Dessa lastfall ligger till grund för utvärderingar av hållfastheten som sker med hjälp av FEM-programvara.

    Arbetet med geometriändringarna sker iterativt. Framtagandet av olika ändringar sker genom löpande FEM-utvärdering av förslag, med påföljande förändring av förslagen. Ändringarna utvärderas slutligen kollektivt. Studier av litteratur och skrivna samt muntliga källor, ligger till grund för arbetet med materialbytet. Materialens fördelar och nackdelar vägs mot varandra och avslutningsvis genomförs en FEM-utvärdering.     

    Rapporten huvudresultat:

    • 5,6 kg per slutväxelhus kan sparas, om föreslagna geometriändringar införs. Detta utan att funktion eller hållfasthet påverkas negativt.

    • 12,8 kg per hus kan sparas ifall föreslagna geometriändringar samt materialbyte till segjärn genomförs, detta sker dock till priset av ökad utböjning (+24 %). 

    • Infästningen kan försvagas genom att fem av de tolv skruvarna avlägsnas. FEM-beräkningar visar att denna förändring och byte av skruvkvalitet, skapar önskad brytpinne i systemet.

    Ändras geometrierna kommer man behöva ta fram nya gjutformar, priset för dessa måste vägas emot vinsten av geometriförändringen. Geometriändringarna består av två typer, dels ändringar som syftar till att spara vikt genom avlägsnande av material. Den andra typen av ändringar sker i syfte att öka husets motstånd mot böjning. Segjärnet SiSSADI har många fördelar, dock medför den låga E-modulen att utböjningen ökar kraftigt, denna utböjning kan ställa till problem och man måste förhålla sig till detta.   

  • 256.
    Johansson, Viktor
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektiva byggnader ikallt klimat: En undersökning av energiprestanda förfyra enfamiljshus i Umeåregionen2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis has been carried out in the autumn of 2011, on assignment of the department of Applied Physics and Electronics (TFE) at Umeå University. The thesis is a part of the ongoing project, Energieffektivt byggande i kallt klimat, which is a collaboration between the municipality of Umeå, Umeå university and market participants in the Umeå region. The goal of this work is to create and compile a solid base of measurements to show the energy saving potential in the housing sector and to explore if there is an increased risk of mold, rot or fungus growth in energy efficient houses. The long-term goal is that the result of this project will lead to increased motivation to build energy efficient houses even in these latitudes.

    A compilation of the energy requirement has been made for four single-familyhouses in the Umeå region throughout the year 2011. Temperatures and humidity has continuously been logged in the various layers of the building components and in indoor and outdoor air. Flow rates and temperatures of water in heating systems and to hot tap water have been logged. Electricity consumption has also been continuously collected. In total, between 27 and 40 sensors were installed in each house.

    The energy use has thereby been identified and categorized according to if the use is for heat, hot tap water, household electricity and in terms of total electricity- and energy use. Performance has been investigated for installations with energy saving purposes such as heat exchangers, a 30 m long preheating pipe buried in the ground and a geothermal heat pump.

    The results of the compilations show that the houses, with normal year corrected values, have an energy requirement for heating and hot tap water at between 67 and 81 kWh/m2y. The heat and hot tap water requirement for one of the houses was only half of the requirement in BBR of 130 kWh/m2y for houses with other type of heating source than electrical heating.

    The measurements show that there is no risk of mold or rot anywhere in any of the houses.

    In one of the houses it was showed that a preheating pipe along with a wellfunctioning heat exchanger was enough so no additional pre-heating of the incoming air was necessary, even during the coldest period of the year.

    The geothermal heat pump delivered in average 2.5 times more energy than it consumed. This reduced the amount of purchased energy for heating and hot tap water by about 60 % on a yearly basis.

    Overall, there is nothing in this research that indicates that there are any hinders for constructing energy efficient buildings in cold climates. No increased risk of rot or mold has been detected which has been a common misconception about energyefficient, airtight houses.

    Rather, there is a quite large saving potential both moneywise for the individual and for the environment, in both the short and the long term.

  • 257.
    Jonas, Brännare
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Säkra drivningsbyten på bandtransportör: Konceptframtagning av ett säkert drivningsbyte på transportband i närheten av roterande produktband2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The report deals with a concept development of safe driving changes in the pelletizing plants KK2 / KK3 LKAB. Because of security risk with a conveyor belt are so close by the band that being renovated the adjacent band has to be stopped. Since the entire production is dependent on the conveyor belt which are adjacent. This means huge economic losses for the company. Therefore, it is desirable to avoid this renovation, and this is why a concept to avoid this are required. The concept is designed for a safe renovation but all the machinery needs to be stopped. The report provide the information of conveyors construction, safety of work with rotating machinery. It is mostly focusing on the technical and mechanical solution of the problem and not so much to the safety law to get this a legal part to use. The problem has existed since the plants were built in the 80s. The reason why the problem is not resolved is that there is no similar product out on the market that can solve the problem.

  • 258.
    Jonas, Burman
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Torrefaction of biomass using hot flue gases2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 259.
    Jonsson, Bertil
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Svensson, Mats Yngve
    Linder, Astrid
    Björnstig, Ulf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    BioRID II manikin and human seating position in relation to car head restraint2008In: International Journal of Crashworthiness, ISSN 1358-8265, E-ISSN 1754-2111, Vol. 13, no 5, p. 479-485Article in journal (Refereed)
    Abstract [en]

    The objective of the study was to compare stature, weight and backset (the horizontal distance (x) between the back of the occupant's head and the front of the seam on top of the head restraint) of the Biofidelic Rear Impact Dummy (BioRID II) to the same variables on seated volunteers in a car. The following methods were used. Data were collected from 154 randomly selected Swedish individuals (78 males and 76 females). The volunteers and the BioRID II were examined in a Volvo V70 car, year model 2003, in three positions: driver (hands on steering wheel), front passenger (hands in lap) and rear passenger. The study results were as follows: the BioRID II was found to correspond approximately to a 35th-45th percentile male in stature (-2 cm), a 35th percentile male in weight (-7 kg), a 96th percentile female in stature (+11 cm) and a 69th percentile female in weight (+8 kg). The BioRID II was designed to represent a male driver. The BioRID II backset corresponded well with the average of the male drivers of its stature. Larger deviations in backset were found for other volunteer sizes and other seating positions. The average backsets were 26 mm for females and 63 mm for males in the front seat positions. The volunteers had larger backset in the driver position (60 mm) than in the front passenger position (29 mm). Smaller differences in backset were seen between the BioRID II and the volunteers in the rear passenger position. This study provides data regarding the occupant size coverage of BioRID II, and unique data regarding backset, of different occupant positions in the car; driver with hands on steering wheel, and front and rear passengers with hands in lap, for female and male in relation to the BioRID II dummy.

  • 260.
    Jonsson, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Konstruktion av viktbärande motståndsvagn: Reglerbar träningsprodukt för varierande underlag2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Balticfitness är ett svenskt företag som tillhandahåller diverse träningsprodukter till flera träningsområden. Detta arbete har gått ut på att konstruera en viktbärande motståndsvagn i samverkan med Balticfitness. Principen bakom dessa motståndsvagnar är ett chassi på hjul med handtag som man trycker eller drar längs en linjär sträcka. På chassit sitter en bromsfunktion som har i uppgift att skapa ett motstånd som gör det tyngre att trycka eller dra vagnen. Till denna konstruktion fanns det även avgränsningar som innebar att studenten inte skulle tillverka motståndsvagnen. Under projektets gång så har en förstudie bedrivits för att granska patent och inhämta konstruktionsunderlag från individer med utbildning inom detta område, som till exempel fysioterapeuter. Design för bromsfunktionen och chassi har stipulerats och sedan konstruerats. Till konstruktion har svaga punkter identifierats och hållfasthets beräkningar genomförts för att undersöka maxlaster. Den slutgiltiga konstruktionen blev ett chassi med längsgående och mellanliggande balkar som vilar på två axlar som sitter i två hjul vardera. På chassit sitter en mekanisk bromsfunktion som vid reglering av motstånd ökar eller minskar friktionen och därmed ökar eller minskar träningsgraden.

  • 261.
    Jonsson, Henrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Optimization of Sub Frames Design: Designing of new sub frame designs with CAD and analysing their strengths with FEA.2017Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
    Abstract [en]

    Ålö is a supplier in the agricultural Machinery Industry. They develop and manufacture mainly front-end loaders and they got other products groups too. One of the other product groups consists of the sub frames. The sub frames are the mechanical components that are required for the front loaders to fit to different tractors. The product integrations section, that develops the sub frames, wants to investigate the strengths of other concepts of designs than their traditional ones.

    New models of sub frames were created by using Solid Edge which is a CAD-system. The models’ strengths were simulated by using Femap which is its built-in FEM-tool for engineering analysis. The FE-analysis were compared to the FE-analysis of the original sub frames.

     

    A total of three design changes were investigated. One set of sub frame was investigated with a new concept of design. Another set of sub frame was investigated with the new concept of design and it was also investigated with thinner plates.

     

    What was concluded is that the design change with thinner plates resulted in a weight reduction of 5 kg but at the cost of higher levels of stress. To verify that the sub frame will last its desired life span prototypes should be physically tested by fatigue test. The new design concept resulted in too big increases of stress levels on one set of sub frame and on another set of sub frame it resulted in small differences of stress but with a weight increase.

  • 262.
    Jonsson, Pierre
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektivisering av transformatorstationer åt Vattenfall Eldistribution AB2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 263.
    Jonsson, Thim
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Miljöcertifiering av befintlig byggnad: Utredning om tillvägagångssätt och tidsåtgång enligt Miljöbyggnad 3.02018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report is a bachelor thesis at Umeå University. The purpose of this report is to show the choice of method, approach and timeframe according to the environmental building for existing buildings. \\ \\ Miljöbyggnad is a certification system in which indicators for energy, environment and materials are examined. If the building meets the requirements, it will receive an environmental certification. Miljöbyggnad started already in 2003, when it was called the Miljöklassad byggnad and was a cooperation between the municipality, companies and government for sustainable development in the construction and real estate sector. This was linked to the environmental goals set by the government in 1999. \\ \\The indicators investigated in this work have been linked to energy and the environment. According to the instructions for environmental construction, many of the indicators can be reported by simulated values or measured/calculated values. \\ The results associated with the indicators have been investigated by measurement, calculation and simulation where comparison of methods has been made. \\ \\ The work has resulted in a proposal for ways in which the company, in connection with an energy declaration, can make a rough estimate of whether an environmental construction process can be done. If the building is considered suitable for such certification, the proposal is that collection of necessary information about the building will take place in the first step. It includes everything from drawings of the entire property to inventory of the property's internal loads. Furthermore, the energy and environmental data of the building will be simulated in order to be able to compare against environmental building requirements. This approach is considered to be most appropriate for most properties. \\ There are easier ways to judge some of the indicators, but it also requires a room/officespace to meet certain conditions.

  • 264.
    Jonsson, Tobias
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Tilluftstemperaturens och frånluftsflödets påverkan på en pappersmaskins ångtork och värmeåtervinning2015Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
  • 265.
    Jonsson, Ulf G
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lindahl, Olof A
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Dept. of Engineering Sciences and Mathematics, Luleå University of Technology, Sweden.
    Andersson, Britt M
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Modeling the high-frequency complex modulus of a silicone rubber using standing lamb waves and an inverse finite element method2014In: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, ISSN 0885-3010, E-ISSN 1525-8955, Vol. 61, no 12, p. 2106-2120Article in journal (Refereed)
    Abstract [en]

    To gain an understanding of the high-frequency elastic properties of silicone rubber, a finite element model of a cylindrical piezoelectric element, in contact with a silicone rubber disk, was constructed. The frequency dependent elastic modulus of the silicone rubber was modeled by a four parameter fractional derivative viscoelastic model in the 100 kHz to 250 kHz frequency range. The calculations were carried out in the range of the first radial resonance frequency of the sensor. At the resonance, the hyperelastic effect of the silicone rubber was modeled by a hyperelastic compensating function. The calculated response was matched to the measured response by using the transitional peaks in the impedance spectrum that originates from the switching of standing Lamb wave modes in the silicone rubber. To validate the results, the impedance responses of three 5 mm thick silicone rubber disks, with different radial lengths, were measured. The calculated and measured transitional frequencies have been compared in detail. The comparison showed very good agreement, with average relative differences of 0.7 %, 0.6 %, and 0.7 % for the silicone rubber samples with radial lengths of 38.0 mm, 21.4 mm, and 11.0 mm, respectively. The average, complex, elastic modulus of the samples were: (0.97 + 0.009i) GPa at 100 kHz and (0.97 + 0.005i) GPa at 250 kHz.

  • 266.
    Kairento, Karl-Oskar
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Konsolidering av bearbetningsfixturer till lyftarmar2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The company Cranab, located in Vindeln, manufactures cranes in varius sizes mostly to forest machines, since a year back they also manufactures cranes to trucks. A crane consists of different components in various sizes such as crane piller, lifting arms, rocker arms, middle boom and inner boom. These components are welded constructions and consists of different details, the different details are produced in a laser cutting process and then welded on to the arm itself. When the arm is complete it is put into a CNC-machine where it is processed. When the arm is ready for the CNC-machine it is placed in a fixture to ensure a more stable processing an mostly to readuce vibrations. The current situation at Cranab is that they use one specific fixture to one specific arm. For this reason it takes a lot of time to change between arms and the fixtures itself takes a lot of place in the workshop. The purpose of this project is to construct a flexible fixture that is able to handle a couple of arms by changing the fixture in a smooth way. A lot of varius factors are important when constructing a fixture that ensures a stable and safe process in the CNC-machine. Cranab are investing a lot of money in a new CNC-machine that will process these arms, the new machine is going to rotate the whole fixture 45 degreese. The fixture that are now used are not able to handle this kind of rotation so except the current requirements the new fixture must be able to hold the whole weight of the arm. During this project the lifting arm to forwarders will be analyzed which is the most complicated part of the crane. The first part of the project will consist of collecting information about the current situation and analyzing the fixtures that are now used, after that the construction of the fixture will be done in the CAD-program Inventor where a koncept will be be developed. The project results in a fixture that can handle eight arms, the current fixtures that are used can only handle a maximum of two arms. With the new fixture, the adjustmets that are necessary when different arms needs to be mounted will be easy to implement and they won’t need a traverse to adjust the fixture. This will make the workprocess of adjusting the fixture much more time efficient. The result is, in comparison with the old fixtures, a clear improvement. Although the project resulted in a raw model of the flexible fixture it is a clear improvement of the existing ones and it is something to continue working with.

  • 267.
    Karlsson, Erik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Dimensionering och detaljkonstruktion av parkeringsbroms: Konstruktion av parkeringsbroms och nödbroms till en elektrisk driven axel för tyngre fordon2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report describes the work process and result of the thesis work for a Bachelor of Science in Mechanical Engineering, 15 credits, at Umeå University during the spring semester of 2016. The work was executed over a period of 10 weeks and was carried out at the company BAE Systems Hägglunds located in Örnsköldsvik, Sweden.

    Bae Systems Hägglund has received a request if it is possible to integrate a parking brake in their current hybrid electrical drive system. The request came from the company Konecrane that manufactures lifting equipment of various kinds. They want to have the drive system with integrated parking brake in their product Reachstacker, which is a terminal truck for ports. The parking brake must also have to function like an emergency brake if there should occur a situation where it is required.

    This report deals with further development of a concept proposal and previous calculations, which includes detailed construction and sizing of the parking brake. The first step is to study previous work to get an idea of ​​the function and the demands on the brakes. Also to see if there are some problems that need to be answered. After the literature study, investigate the external sources and suppliers that manufactures parts that are not produced on site at BAE System Hägglunds.

    The components that are included in the parking brake are calculated and constructed after the desired requirements. The CAD program that is used in this project is CATIA V5. Due to complications of sizing and ordering of friction discs for the parking brake a new delimitation was added. Instead of one specific solution, five different concepts with regard of materials and friction were produced. The different solutions can be studied when information of the specifics of the friction plates has been decided, then choose the solution that has the best fit.

  • 268.
    Karlstedt, Rebecca
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Kartläggning för lastning av provfordon2014Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
    Abstract [sv]

    På Scanias R&D-avdelning i Södertälje sker dagligen tester av deras fordon, både av lastbilar och bussar. Många av provningarna kräver att fordonen är lastade för att kunna testa prestandan. Vid lastning av lastbilar finns ett välprövat system, men när det kommer till bussar finns inget fungerande system för hur lastningen ska ske. Många olika varianter finns och i slutändan används den lösning som passar bäst för stunden. Avsikten med detta projekt är att kartlägga hur lastning ska kunna utföras på ett rätt sätt med avseende på säkerhet och hållbarhet, samt ta fram en ny flexibel konstruktion som medverkar till att lastning blir ett enklare moment.

    Vid avdelningen NB (Hybrid Technology Development) testas fordon dagligen. Proven kräver alltifrån dellast till maxlast och lastning av fordonen sker flera gånger per år. Varje gång en buss ska lastas spenderas det mycket tid och resurser. Vid nuläget saknas det ett vägledande dokument för hur lastning samt lastsäkring ska ske på ett sätt som medger stor säkerhet och effektivitet. Men även en flexibel lastningsmetod som ger möjlighet till en tidseffektiv lastning, vilket minskar behovet av tid och resurser.

    Med hjälp av anställdas erfarenheter och kunskaper inom detta område har ett vägledande dokument inför lastning/lastsäkring framställts där viktiga aspekter har lyfts fram. Ett förslag på en ny konstruktion där lastningsmomentet ska avlastas har tagits fram. Genom att använda redan befintliga vikter underlättas många olika moment likaså att inget extra lager för nya vikter behövs.

  • 269.
    Karolina, Bengtsdotter
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Interaktioner mellan svavel, klor och kvicksilver vid avfallsförbränning2018Independent thesis Advanced level (professional degree), 300 HE creditsStudent thesis
    Abstract [en]

    For a long time, mercury has been a very popular to use in different kinds of products due to its unique properties. Which has led to a lot of different things containing mercury ends up in waste plants to be incinerated. Mercury are also considered to be one of the most dangerous substances and therefore emissions needs to be kept at minimum. Oxidizing mercury from its form Hg0 to Hg2+ is considered to be extremely important due to the later are easier to remove from the flue gas. The main objective with this thesis was to investigate if mercury would exist more in its elementary form Hg0 than its oxidized state Hg2+ in the flue gas when the ratio between sulfur and chlorine was changed. The former is insoluble in water and therefore difficult to remove from the flue gas with today’s cleaning facility’s. It is also considered one of the more dangerous substances in the world. The project was done in collaboration with Umeå Energi AB. The method that was used to explore this was measuring the mercury content of the flue gas from the waste fired boiler Dåva 1 outside Umeå. The measurement was done with and without extra sulfur added to the fuel in the form of car tires. An additional analysis was done on the ash from the fabricfilter and from the superheater to see if there was something there to give some clarity on why there would be any change in the amount of mercury. The measurement did indeed indicate that sulfur increases the amount of mercury in the flue gas. The main theory to why this has occurred was the increased amount of SO3, which could be found in the flue gas when extra sulphur was added. SO3 is then absorbed by the activated carbon that is added to the flue gas that should have absorbed Hg0 instead. However, this result is not conclusive and further studies needs to be done. Another possible theory to why this has occurred could be that the increase of sulfur could lead to more Na2SO4 in the particle filter. Which could have led to a decrease of NaCl in the filter that could perhaps be a more efficient oxidizing agent of Hg0 than HCl. Another thing that has been revealed is that the cleaning systems that is used today is capable of cleaning mercury from the flue gas even though the added sulfur caused an increase in the amount.

  • 270.
    Kasolis, Fotios
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    The material distribution method: analysis and acoustics applications2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    For the purpose of numerically simulating continuum mechanical structures, different types of material may be represented by the extreme values {,1}, where 0<1, of a varying coefficient  in the governing equations. The paramter  is not allowed to vanish in order for the equations to be solvable, which means that the exact conditions are approximated. For example, for linear elasticity problems, presence of material is represented by the value  = 1, while  =  provides an approximation of void, meaning that material-free regions are approximated with a weak material. For acoustics applications, the value  = 1 corresponds to air and  to an approximation of sound-hard material using a dense fluid. Here we analyze the convergence properties of such material approximations as !0, and we employ this type of approximations to perform design optimization.

    In Paper I, we carry out boundary shape optimization of an acoustic horn. We suggest a shape parameterization based on a local, discrete curvature combined with a fixed mesh that does not conform to the generated shapes. The values of the coefficient , which enters in the governing equation, are obtained by projecting the generated shapes onto the underlying computational mesh. The optimized horns are smooth and exhibit good transmission properties. Due to the choice of parameterization, the smoothness of the designs is achieved without imposing severe restrictions on the design variables.

    In Paper II, we analyze the convergence properties of a linear elasticity problem in which void is approximated by a weak material. We show that the error introduced by the weak material approximation, after a finite element discretization, is bounded by terms that scale as  and 1/2hs, where h is the mesh size and s depends on the order of the finite element basis functions. In addition, we show that the condition number of the system matrix scales inversely proportional to , and we also construct a left preconditioner that yields a system matrix with a condition number independent of .

    In Paper III, we observe that the standard sound-hard material approximation with   gives rise to ill-conditioned system matrices at certain wavenumbers due to resonances within the approximated sound-hard material. To cure this defect, we propose a stabilization scheme that makes the condition number of the system matrix independent of the wavenumber. In addition, we demonstrate that the stabilized formulation performs well in the context of design optimization of an acoustic waveguide transmission device.

    In Paper IV, we analyze the convergence properties of a wave propagation problem in which sound-hard material is approximated by a dense fluid. To avoid the occurrence of internal resonances, we generalize the stabilization scheme presented in Paper III. We show that the error between the solution obtained using the stabilized soundhard material approximation and the solution to the problem with exactly modeled sound-hard material is bounded proportionally to .

  • 271.
    Kasolis, Fotios
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Wadbro, Eddie
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Berggren, Martin
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Preventing resonances within approximated sound-hard material in acoustic design optimization2014In: 1st International Conference on Engineering and Applied Sciences Optimization, 2014Conference paper (Other academic)
  • 272.
    Kempe, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utvärdering och åtgärdsförslag av energianvändning i kontorsbyggnad2015Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [en]

    Abstract

    Embla 5 is an office building which has done a large improvement. The clients of this building has made an order of WSP and the student Anders Kempe to calculate the use of energy for the building, and after that result proposing further measures which can decrease the energy use of Embla 5.

    The ground for this report is when calculation of the present energy use of the building is stated. To make that information of a number of parameters such as envelope, the heating system and ventilation has been located and set in to the simulation program IDA ICE which calculate the energy use.

    To improve the energy use further this project has been concentrated to change the system of ventilation. Today the ventilation system is of the kind CAV (constant air volume) and the air flow is dimensioned for after recommendations from BBR and Arbetsmiljöverket in the office spaces. Consider that Embla 5  is an office building where the people only staying for 8-10 hours/day so was the ide to see how much energy saving if the air flow is reduced the time people not being in the building. This VAV-system (variable air volume) was set to go with full air flow weekdays 06:00-19:00 when people can be in the local. All the time around that the air flow is been reduced to 20 % of dimensioned flow (solution 1) and 40 % of dimensioned flow (solution 2) with the same kind of time control. By these solutions the rate of energy use is been calculated and been compared to the present energy use.             

    The saving of energy for the two solutions been around the same about 100 000 [kWh/year]. With a energy price of 1 [SEK/kWh] the saving in money being 100 000 [SEK/year].

    Before Embla 5 renovated the heating rate were 400 000 kWh/year and after renovation the heating rate were 300 000 kW/year. The heating rate had reduced thus the building had been four times bigger. The reason of that is the older part of the building had very large transmissions losses and newer part of the building was built with material with low u-value which decreases the transmissions losses. Another reason is that a new FTX-system is placed in the building with a better efficiency than the older FTX-system.         

  • 273.
    Kero, Johan
    Umeå University, Faculty of Science and Technology, Physics.
    High-resolution meteor exploration with tristatic radar methods2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A meteor observed with the naked eye is colloquially called a shooting star. The streak of light is generated by an extra-terrestrial particle, a meteoroid, entering the Earth’s atmosphere. The term meteor includes both luminosity detectable by optical means and ionization detectable by radar. The radar targets of meteor head echoes have the same motion as the meteoroids on their atmospheric flight and are relatively independent of aspect angle. They appear to be compact regions of plasma created at around 100 km altitude and have no appreciable duration.

    This thesis reviews the meteor head echo observations carried out with the tristatic 930 MHz EISCAT UHF radar system during four 24h runs between 2002 and 2005, and a 6h run in 2003 with the monostatic 224 MHz EISCAT VHF radar. It contains the first strong observational evidence of a submillimeter-sized meteoroid breaking apart into two distinct fragments. This discovery promises to be useful in the further understanding of the interaction processes of meteoroids with the Earth’s atmosphere and thus also the properties of interplanetary/interstellar dust.

    The tristatic capability of the EISCAT UHF system makes it a unique tool for investigating the physical properties of meteoroids and the meteor head echo scattering process. The thesis presents a method for determining the position of a compact radar target in the common volume of the antenna beams and demonstrates its applicability for meteor studies. The inferred positions of the meteor targets are used to estimate their velocities, decelerations, directions of arrival and radar cross sections (RCS) with unprecedented accuracy. The head echoes are detected at virtually all possible aspect angles all the way out to 130° from the meteoroid trajectory, limited by the antenna pointing directions. The RCS of individual meteors simultaneously observed with the three receivers are equal within the accuracy of the measurements with a very slight trend suggesting that the RCS decreases with increasing aspect angle.

    A statistical evaluation of the measurement technique shows that the determined Doppler velocity agrees with the target range rate. This demonstrates that no contribution from slipping plasma is detected and that the Doppler velocities are unbiased within the measurement accuracy. The velocities of the detected meteoroids are in the range of 19-70 km/s, but with very few detections at velocities below 30 km/s. The thesis compares observations with a numerical single-body ablation model, which simulates the physical processes during meteoroid flight through the atmosphere. The estimated meteoroid masses are in the range of 10-9 - 10-5.5 kg.

  • 274.
    Kerwien, Joakim
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Vibrationsdämpare för frontlucka: Koncept för vibrationsdämpare med justering2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Vibration-dampeners for front lid FH/FM

     

    Concepts for vibration-dampers with adjustment

     

    Joakim Kerwien

     

    Abstract

     

    The model-lines FH and FM from Volvo Trucks, have vibration dampers in the front of the cab.  These dampen the front lid and reduces the risk for the front lid to slam into the door. The current vibration damper design is not position adjustable, which is something Volvo wants to have. This makes it easier to adjust the front lid, and get a good gap- and flush-positioning of the front lid, that gives an excellent quality impression for the customer.

    Several concepts are to be developed, which will be compared to each other in a decision matrix.

    The work is carried out at Volvo GTT, the design engineering branch of Volvo GTO in Umeå.

     

    Important delimitations:

    • Development of concepts, no production of parts yet.
    • No strength of materials-calculations or FEM-analysis by me.
    • Use CATIA v5 for CAD-purposes.

     

    Work done:

    Market research has been done, towards rival companies, also researched some former concepts developed by Volvo employees, then I have made some different vibration dampers with adjustability in CATIA v5.

    The concepts developed were then put into a Pugh-matrix, where important attributes and qualities like price, manufacturability, difficulty of assembly were compared with the current damper.

     

    Results of the Pugh-matrix:

    Concepts 2 and 4 were best in this analysis, both got the same amount of points, although this was without any cost analysis involved.

     

    Discussions and Conclusions:

    Two of the concepts are better suited for further development, concepts 2 and 4, both from cost reasons, also they both have adequate adjustability.

    The conclusion is that it is feasible to make different concepts for vibration-dampers with adjustability. The hard part to solve is how you can adjust the dampeners with the front lid closed. 

  • 275.
    Khalanski, Aliaksei
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Livscykelanalys för olika brytartekniker på mellanspänningsnivå2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Gasen svavelhexafluorid, SF6, har använts i världen för olika ändamål sedan 1960-talet på grund av dess framträdande isolerande och ljusbågssläckande egenskaper. Ett av de bredaste användningsområdena för gasen idag är tillverkningen av mellan- och högspänningsställverk, där den används för släckning av ljusbågar och som ett isolationsmedium i vissa komponenter, till exempel i brytare. De unika fysikaliska egenskaperna av SF6 gör elektrisk utrustning innehållande den gasen mer fördelaktig ur utrymmessynpunkt jämfört med andra tekniska lösningar. Svavelhexafluorid är dock en 23 900 gånger starkare växthusgas på ett 100 års perspektiv jämfört med koldioxid och med det omfattas av Kyotoprotokollet. Det faktumet gör att gasen kräver ett särskilt hanteringssätt under hela dess livscykel eftersom allt läckage av SF6 absolut ska undvikas.

    Skellefteå Kraft använder SF6-gas i sina brytare på hög- och mellanspänningsnivå och eftersom bolaget har beslutat om att utvecklas mot att ha en 100 procent hållbar energiproduktion har användningen av SF6-gas fått större uppmärksamhet. På 36 kV spänningsnivå finns det en teknisk lösning av brytare där isolationsmediet utgörs av luft istället för gas. Dock är nackdelen med den lösningen att den generellt kräver mer utrymme, vilket är viktigt i det sammanhanget ity moderna ställverk på den spänningsnivån placeras inomhus för att minska behovet av underhåll. Syftet med denna studie är därför att jämföra miljöpåverkan från dessa två brytartekniker, nämligen ett luftisolerat ställverk och ett ställverk med brytare i gastank. Studien utgörs i form av en livscykelanalys och kommer att fungera som kunskapsunderlag för Skellefteå Kraft vid framtida reinvesteringar i mellanspänningsställverk.

    Eftersom SF6 är en koldioxidekvivalent fokuserade denna studie enbart på miljöpåverkan i form av utsläpp av koldioxidekvivalenter. Programmet för livscykelanalyser Open LCA tillsammans med Excel användes för att utföra beräkningarna. Miljöpåverkan från ett inomhusställverk antas inkludera två bidrag: ställverksfacken och ställverksbyggnader där betong-, container- och träbyggnader dessutom jämfördes med varandra. Resultatet i denna studie presenterar klimatpåverkan från ett ställverksutförande med två inkommande linjer med totalt fem brytare, dock kan den skapade excelfilen beräkna klimatpåverkan för en valfri ställverksuppställning på spänningsnivån 36 kV. I livscykelanalysen har ett flertal grova antaganden gjorts vilket gör den till en väldigt generell studie, dock gjordes det lika antaganden för de båda typerna av brytare vilket gör att resultatet fungerar som en jämförelse och inte de absoluta värdena på koldioxidutsläppen.

    Resultat visade att vid antagandet om gasläckaget om 1 procent vid produktionen, 0,1 procent vid driften och 1 procent vid avvecklingen av "gas"-ställverket (1;0,1;1 procent) är klimatpåverkan för de båda typerna av ställverk lika stor, med undantaget för träbyggnaden, där "gas"-ställverket orsakar ett cirka 16 procent större utsläpp i jämförelse med "luft"-ställverket. Därjämte vid antagandet om ett större läckage, nämligen 3;0,1;5 procent, vilket också ses som mer realistisk, blir klimatpåverkan för ett "gas"-ställverk från 38 till 67 procent större, beroende på byggnad.

    Även om det ställs särskilda krav på hanteringen av SF6 finns det alltid en liten risk att gasen läcker ut i atmosfären i större mängder. Tillverkarna påstår att båda typerna av brytare är underhållsfria under hela sin livslängd. Dock har ett luftisolerat ställverk större möjligheter för funktionstester och underhåll, vilket också minskar risker för haverier. "Gas"-ställverk saknar nästan helt dessa möjligheter. Ur säkerhetssynpunkt anses ett luftisolerat ställverk vara ett bättre alternativ och ur miljösynpunkt anses de två alternativen vara jämbördiga.

  • 276.
    Kjeang, Erik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Goldak, J
    Carleton University, Ottawa, Canada.
    Golriz, Mohammad R
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Gu, J
    Carleton University, Ottawa, Canada.
    James, D
    Energy Visions Inc., Calgary, Canada.
    Kordesch, K
    Technical University Graz , Austria.
    Modeling methanol crossover by diffusion and electro-osmosis in a flowing electrolyte direct methanol fuel cell2005In: Fuel Cells, ISSN 1615-6846, E-ISSN 1615-6854, Vol. 5, no 4, p. 486-498Article in journal (Refereed)
    Abstract [en]

    A CFD model is created to analyze methanol transport in a flowing electrolyte direct methanol fuel cell (FE-DMFC) by solving the 3D advection-diffusion equation, with consideration of electro-osmosis. The average methanol flux at the anode and cathode surfaces is simulated and compared to equivalent direct methanol fuel cells. Methanol crossover is defined as methanol flux at the cathode surface, and the results reveal that methanol crossover can be drastically reduced by the flowing electrolyte. The performance of the FE-DMFC at peak power current density is evaluated, and diffusion is shown to be the dominant contribution, although electro-osmosis increases with current density. The power consumption of the electrolyte pump is shown to be negligible compared to the cell power output. This indicates that thin electrolyte channels with high flow rates could further improve the efficiency

  • 277.
    Kjellgren, Filip
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Konstruktion av hydraulisk testrigg för skruvförband2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 278.
    Kjellsson, Anton
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analys av energi, kostnad och CO2-utsläpp med/utan ångtork och förbränning/sluttäckning med slam rörande slamhantering på ett avloppsreningsverk i Umeå2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    De ökade deponi- och transportkostnaderna har skapat ett ökat intresse att effektivisera hanteringen av avloppsslam. Umeås allmänna avloppsreningsverk (Vakin) tar emot avloppsvatten från mer än 80 000 hushåll och företag och det mesta leds till reningsverket på Ön. Efter 2020 upphör avtalet med Dåva deponi om att avloppsreningsverket får använda slammet till sluttäckning av deponier. Ett alternativ till deponering är torkning med efterföljande förbränning.Detta examensarbete har genomförts på uppdrag av Vakin och syftet var att kartlägga energiflödena och CO2-utsläppen före och efter en implementering av en ångtork i byggnaderna rörande slamhantering. Även effekter av förbränning respektive deponering av slam har inkluderats. Ett mål var presentera ett systemförslag för hur ångtorken kan implementeras till befintlig anläggning. För att uppnå syftet inhämtades data genom inventering på plats och i projektplaneringsverktyget Projectplace. Därefter beräknades och sammanställdes energibehovet, kostnaden och klimatpåverkan för respektive energiförbrukande enhet i Microsoft Excel Förslaget till implementering av ångtorken är baserat på litteraturdata.Resultatet visar att det årliga energibehovet för slamhantering skulle öka från cirka 2 700 MWh till cirka 3 000 MWh. Vilket resulterar i att den årliga kostnaden för slamhantering ökar från cirka 6,2 miljoner kronor till cirka 7,5 miljoner kronor. Men den årliga klimatpåverkan skulle minska från cirka 930 ton CO2 till cirka 490 ton CO2 med en ångtork. Det årliga elbehovet för slamhantering ökar från inget energibehov till 2 100 MWh vid en installation av en ångtork. Detta eftersom cirka hälften av biogasen som tidigare användes till att producera el- och värmeenergi förväntas användas i ångtorken. Detta resulterar i att den årliga elkostnaden minskar från en intäkt på 650 000 kronor till en kostnad på cirka 4,6 miljoner kronor. Vidare ökar den årliga klimatpåverkan för elen från cirka 10 ton CO2 till cirka 180 ton CO2.Det årliga energibehovet för transporten minskar från cirka 2 700 MWh till cirka 900 MWh vid en installation av en ångtork. Eftersom ångtorken reducerar mängden slam som ska transporteras. Vilket resulterar i att den årliga kostnaden för transporten minskar från cirka 4,1 miljoner kronor till cirka 1,4 miljoner kronor. Även klimatpåverkan för transporten minskar från cirka 720 ton CO2 till cirka 240 ton CO2. Det årliga energibehovet idag är oförändrat när Vakin förbränner det torkade slammet. Eftersom energibehovet för sluttäckning inte beaktats och energibehovet för förbränning av torkat slam är noll. Den årliga kostnaden minskar från cirka 2,8 miljoner kronor till cirka 1,6 miljoner kronor. Eftersom mängden slam minskar mer än vad kostnaden för att förbränna slammet ökar. Den årliga klimatpåverkan minskar från cirka 180 ton CO2 till inget CO2-utsläpp. Eftersom klimatpåverkan att förbränna förnybart biologiskt material är noll.

    Energikartläggningen av fastigheterna visar att idag förbrukar utrustningen och belysningen rörande slamhantering cirka 760 MWh respektive 25 MWh el. Byggnaderna rörande slamhantering förbrukar idag cirka 1 200 MWh (byggnad 4) respektive 500 MWh (byggnad 5) värmeenergi. Dessa värden är jämförbara med andra liknande slamhanteringsanläggningar. Ur ett hållbarhetsperspektiv rekommenderas att Vakin installerar en ångtork, vilket medför bland annat en minskad årlig transportsträcka och därav reduceras CO2-utsläppen från transporten. Den mest lämpliga integreringen av en ångtork till ett avloppsreningsverk är att upprätthålla en arbetstemperatur för rötkamrarna med värmen från kondensationen av det förångade vattnet, återcirkulera den överhettade ångan som värms av förbränningen av metangasen från rötkamrarna samt blanda torkat slam med blöt slam för att undvika slammets klibbiga fas.

  • 279. Klarbring, Anders
    et al.
    Torstenfelt, Bo
    Hansbo, Peter
    Larson, Mats G.
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Optimal design of fibre reinforced membrane structures2017In: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 56, no 4, p. 781-789Article in journal (Refereed)
    Abstract [en]

    A design problem of finding an optimally stiff membrane structure by selecting one-dimensional fiber reinforcements is formulated and solved. The membrane model is derived in a novel manner from a particular three-dimensional linear elastic orthotropic model by appropriate assumptions. The design problem is given in the form of two minimization statements. After finite element discretization, the separate treatment of each of the two statements follows from classical results and methods of structural optimization: the stiffest orientation of reinforcing fibers coincides with principal stresses and the separate selection of density of fibers is a convex problem that can be solved by optimality criteria iterations. Numerical solutions are shown for two particular configurations. The first for a statically determined structure and the second for a statically undetermined one. The latter shows related but non-unique solutions.

  • 280.
    Koblik, V.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Polyakhova, E.
    Sokolov, L.
    Solar sail near the Sun: Point-like and extended models of radiation source2011In: Advances in Space Research, ISSN 0273-1177, E-ISSN 1879-1948, Vol. 48, no 11, p. 1717-1739Article in journal (Refereed)
    Abstract [en]

    Some modifications of solar sail radiation pressure forces on a plate and on a sphere for use in the numerical simulation of 'local-optimal' (or 'instantaneously optimal') trajectories of a spacecraft with a solar sail are suggested. The force model development is chronologically reviewed, including its connection with solar sail surface reflective and thermal properties. The sail surface is considered as partly absorbing, partly reflective (specular and diffuse), partly transparent. Thermal balance is specified because the spacecraft moves from circular Earth orbit to near-Sun regions and thermal limitations on the sail film are taken into account. A spherical sail-balloon can be used in near-Sun regions for scientific research beginning with the solar-synchronous orbit and moving outward from the Sun. The Sun is considered not only as a point-like source of radiation but also as an extended source of radiation which is assumed to be consequently as a point-like source of radiation, a uniformly bright flat solar disc and uniformly bright solar sphere. (C) 2011 COSPAR. Published by Elsevier Ltd. All rights reserved.

  • 281. Kramb, Jason
    et al.
    Konttinen, Jukka
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Salo, Kari
    Roberts, Michael
    Elimination of arsenic-containing emissions from gasification of chromated copper arsenate wood2016In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 181, p. 319-324Article in journal (Refereed)
    Abstract [en]

    The behavior of arsenic in chromated copper arsenate containing wood during gasification was modeled using thermodynamic equilibrium calculations. The results of the model were validated using bench-scale gasification tests. It is shown that over 99.6% of arsenic can be removed from the product gas by a hot filter when the gas is cooled below the predicted condensation temperature.

  • 282.
    Kuba, Matthias
    et al.
    Technische Universität Wien, Institute of Chemical Engineering.
    He, Hanbing
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Kirnbauer, Friedrich
    Technische Universität Wien, Institute of Chemical Engineering.
    Skoglund, Nils
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Hofbauer, Hermann
    Technische Universität Wien, Institute of Chemical Engineering.
    Mechanism of Layer Formation on Olivine Bed Particles in Industrial-Scale Dual Fluid Bed Gasification of Wood2016In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 30, no 9, p. 7410-7418Article in journal (Refereed)
    Abstract [en]

    Utilization of biomass as feedstock in dual fluidized bed steam gasification is a promising technology for the substitution of fossil energy carriers. Experience from industrial-scale power plants showed an alteration of the olivine bed material due to interaction with biomass ash components. This change results mainly in the formation of Ca-rich layers on the bed particles. In this paper, a mechanism for layer formation is proposed and compared to the better understood mechanism for layer formation on quartz bed particles. Olivine bed material was sampled at an industrial-scale power plant before the start of operation and at predefined times after the operation had commenced. Therefore, time-dependent layer formation under industrial-scale conditions could be investigated. The proposed mechanism suggests that the interaction between wood biomass ash and olivine bed particles is based on a solid–solid substitution reaction, where Ca2+ is incorporated into the crystal structure. As a consequence, Fe2+/3+ and Mg2+ ions are expelled as oxides. This substitution results in the formation of cracks in the particle layer due to a volume expansion in the crystal structure once Ca2+ is incorporated. The results of this work are compared to relevant published results, including those related to quartz bed particles.

  • 283.
    Kuba, Matthias
    et al.
    Technische Universität Wien, Institute of Chemical Engineering.
    He, Hanbing
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Kirnbauer, Friedrich
    Technische Universität Wien, Institute of Chemical Engineering.
    Skoglund, Nils
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Hofbauer, Hermann
    Technische Universität Wien, Institute of Chemical Engineering.
    Thermal stability of bed particle layers on naturally occurring minerals from dual fluid bed gasification of woody biomass2016In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 30, no 10, p. 8277-8285Article in journal (Refereed)
    Abstract [en]

    The use of biomass as feedstock for gasification is a promising way of producing not only electricity and heat but also fuels for transportation and synthetic chemicals. Dual fluid bed steam gasification has proven to be suitable for this purpose. Olivine is currently the most commonly used bed material in this process due to its good agglomeration performance and its catalytic effectiveness in the reduction of biomass tars. However, as olivine contains heavy metals such as nickel and chromium, no further usage of the nutrient-rich ash is possible, and additional operational costs arise due to necessary disposal of the ash fractions. This paper investigates possible alternative bed materials and their suitability for dual fluid bed gasification systems focusing on the behavior of the naturally occurring minerals olivine, quartz, and K-feldspar in terms of agglomeration and fracturing at typical temperatures. To this end, samples of bed materials with layer formation on their particles were collected at the industrial biomass combined heat and power (CHP) plant in Senden, Germany, which uses olivine as the bed material and woody biomass as feedstock. The low cost logging residue feedstock contains mineral impurities such as quartz and K-feldspar, which become mixed into the fluidized bed during operation. Using experimental and thermochemical analysis, it was found that the layers on olivine and K-feldspar showed a significantly lower agglomeration tendency than quartz. Significant fracturing of particles or their layers could be detected for olivine and quartz, whereas K-feldspar layers were characterized by a higher stability. High catalytic activity is predicted for all three minerals once Ca-rich particle layers are fully developed. However, quartz may be less active during the buildup of the layers due to lower amounts of Ca in the initial layer formation.

  • 284.
    Källgren, Antonio
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Konstruktion av belastningsmaskin2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report deals with the development of a self-designed bending machine. Baltic Fitness's intention is to start competing on the market with self-made barbells. The test equipment makes careful tests on the bars before sale. Actors use this technique to check the strength of the bars. Various design proposals were developed and compared. The best suited was then chosen. The requirement for the construction was to handle the loading test on bars with 1500 and 2000 kilograms. In addition, the operation of the equipment must be simple, which means that the design solution has to be well thoughtful. This is because the tests on a bar has to be in a safe and smooth manner. The report describes the approach from idea to complete design documentation. All parts were developed and dimensioned in the 3D Workshop Solid Works. It is reported necessary calculations of forces and torques, as well as strength calculations. At the end of the report, it´s presented price estimate and productions documentation for the entire construction.

  • 285.
    Kälvelid, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Numerical Modeling of Plain Journal Bearings within a Heavy-Duty Engine Oil System using GT-SUITE2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Main and connecting rod bearings along the crankshaft in a heavy-duty engine oil system requires efficient feed of oil flow to ensure the performance of lubrication, cooling and cleaning. The bearings and builded bearing models considered in this work are based on a Volvo 13L engine. Two main models to predict the oil flow in main and connecting rod bearings have been investigated using the system analysis software GT-SUITE. These two models are based on two numerical methods called  the Mobility method and the Reynold's equation respectively. The main bearing and the connecting rod large end bearing loads calculated in the present work is similar to the reference bearing loads, especially for connecting rod large end bearing and at lower engine speeds. For higher engine speeds, the present load results are far off,  compared to the reference load results. This difference at the higher engine speeds showed also an increased difference in the oil volume flow rates. But more information regarding the calculations of the reference loads is needed to analyze the differences further. Considering the "split lines", where the upper and the lower bearing shell meet, in the bearing models increased the oil volume flow rate with 13.3\% on average for the main bearing. Main bearing stand for 86\% of the total flow whilst connecting rod large end and small end bearing stand for the rest 13\% and 1\% of the total flow. The feed of oil to main bearing and connecting rod large end bearing appears continuously whilst the feed of oil to connecting rod small end bearing appears in the form of a few pulsations. Comparing to the numerical reference flow results, the results in this work are similar at high oil temperatures and at low engine speeds, otherwise the results are far off. Considering the Reynold's equation when predicting the oil volume flow rates in plain journal bearings is a more accurate way than using the Mobility method since it takes more specific geometrical irregularities into account. The oil volume flow rate for main bearing differ with 2.7\% on average when solving the Reynold's equation compared to the Mobility method.

  • 286.
    Kühn, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energy efficiency and harmonics in electric power systems2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 287.
    Lacis, Ugis
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Modelling air flow in the larynx.2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 288.
    Lacoursière, Claude
    Umeå University, Faculty of Science and Technology, High Performance Computing Center North (HPC2N). Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Regularized, Stabilized, Variational Methods for Multibodies2007In: The 48th Scandinavian Conference on Simulation and Modeling (SIMS 2007) / [ed] Peter Bunus, Dag Fritzson and Claus Führer, Linköping: Linköping University Electronic Press, 2007, p. 40-48Conference paper (Refereed)
    Abstract [en]

    A time-discrete formulation of the variational principle of mechanics is used to construct a novel first order, fixed time step integration method for multibody systems subject to mixed constraints. The new stepper, coined Spook, includes physics motivated constraint regularization and stabilization terms. The stepper is proved to be stable for the case of linear constraints, for non-zero regularization and stabilization parameters. For fixed stabilization value, the regularization can be made arbitrarily small, corresponding to arbitrarily stiff penalty forces. The “relaxed” constraint formulation permits a separation of time scales so that stiff forces are treated as relaxed constraints. Constraint stabilization makes the stiff forces modeled this way strictly dissipative, and thus, the stepper essentially filters out the high oscillations, but is rigorously symplectic for the rest of the motion. Spook solves a single linear system per time step and is insensitive to constraint degeneracies for non-zero regularization. In addition, it keeps the constraint violations within bounds of O(h2), where h is the time step. Because it is derived from the discrete variational principle, the stepping scheme globally preserves the symmetries of the physical system. The combination of these features make Spook a very good choice for interactive simulations. Numerical experiments on simple multibody systems are presented to demonstrate the performance and stability properties.

  • 289.
    Lantto, Martin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nötningsrigg för länkkrokar: Länkkrokar för band på skogsmaskiner2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project was based on the development of a wear/fatigue rig for link hooks for Olofsfors AB. The goal was to find a solution for this and at a later stage also produce a prototype. The link hooks currently have a significantly shorter life than the rest of the construction. The purpose of the rig is to be able to compare materials against each other in the future, thus developing a better link system.

    In order to solve the problem and understand it, an analysis of the character of the wear is required. Careful studies were done before the actual work started. After that, the project went through two phases. The first phase was to develop a concept and phase two was then to realize this concept in a 3D prototype.

    The result ultimately did not meet the goals before the end of the course but is on the right track. There is a well-developed concept in form of a 3D prototype. The remaining work before a real prototype can begin to be manufactured is to review and reinforce the design where needed.

  • 290.
    Larsdotter, Linn
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Hur påverkar en ökad andel solceller Umeå Energis elnät?: – En utredning med fokus på spänningsvariationer och osymmetri inom landsbygds- och tätortsnät vid en- och trefasanslutning av solcellsanläggningar2014Independent thesis Advanced level (professional degree), 300 HE creditsStudent thesis
    Abstract [en]

    A good power quality can be an important prerequisite to achieve a sustainable society. Scandinavia's electrical system is in many respects superior, and Sweden has a fossil free electricity generation at 97 % and a reliability of electricity distribution at 99.98 %. Meanwhile, the EU has an ambition to expand the electricity market in order to achieve a joint trading business across Europe. This cross-border market will result in a large proportion of fossil energy sources integrated into our electrical system, which also leads to an increased need for renewable electricity production in Sweden. One part of this development is to increase the share of renewable micro generation that is locally or regionally connected to the power grid. Distributed generation can have advantages as reduced network losses, an increased energy supply and a reduction of the fossil energy use in Europe. But it has also been shown that it gets harder for the electric companies to provide their customers with electricity of good quality when the number of installations increases. An improved power quality implicates reducing events and phenomena in the power grid that affect machinery and electrical appliances negatively. This study focuses mainly on the voltage variations and unbalances that can arise when the proportion of PV-systems increases. One of the main reasons for voltage variations is the reversed power flow that migrates "upwards" in the grid when the PV-systems produce and sell their excess to the grid. The reason for unbalance in the low voltage network is mainly loads or production with uneven distribution between the three phases. An acceptable voltage variation should not exceed ± 10 % of the reference voltage and a balanced state is crossed at 2 %. This study has carried out simulations on three of Umeå Energi´s low voltage networks with different customer configurations and network structure. The grids were assigned virtual PV-systems for 25, 50, 75 or 100 % of the customers, and the phase voltages, unbalances and overloaded lines affected by the output of 1-5 kW from the connected facilities were studied. The differences in voltage at single and three phase connection and differences between customers located near and far from the substation have been investigated. Measurements have also been made on an existing PV-installation. The simulations show that the customers who are placed far out in the network are affected most strongly by the changes, while customers close to the transformer are nearly unaffected by the changes, even with a one phase output (via L1) from all customers at 5 kW. In the simulated scenarios two networks has unbalance as a limiting factor, whereas the third network suffer unacceptable voltage rise and unbalance at nearly the same time. In the extreme scenario with an output power of 5 kW through L1 from 100 % of the costumers in the same network the lines and cables are still not overloaded, which proves that overloaded cables is a secondary problems compared to voltage variations and unbalances. The conclusion is that we do not see any serious threats to the quality of electricity at a larger share of PV-systems, as long as the installations are done in networks with a reliable dimensioning and a great awareness of the importance of three phase connections. However, the simulations have shown that there is an impact when many customers have a large production with an uneven output on the grid at the same time. One should therefore avoid scenarios where all costumers in the same network area has a PV-system with a power output in one single phase, while the loads are very low.

  • 291.
    Larsson, Albin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    NOx-reducerande åtgärder vid låg last av en fastbränslepanna med ureabaserat SNCR-system: Inverkan av körsätt och praktiska åtgärder2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    SCA Obbola AB is a kraft pulp mill that produces and sells packaging paper. The steam demand is covered by a recovery boiler and a solid fuel boiler (consists of two parallel solid fuel furnaces and a boiler). Adjustments in steam production are foremost made by the solid fuel boiler. Previously made energy-reducing measures at the mill has lowered the steam demand which forces the solid fuel boiler to low steam production. The solid fuel boiler produces over 25 GWH/year and is therefor bound by the Swedish nitrous oxide charge, but is also restricted to a monthly mean value of 70 mg/MJ. This mean value was exceeded in July 2016, which is thought to be a result of forced limitation in steam production. NOx emissions are reduced secondarily by an urea-based SNCR-system where its efficiency depends on several parameters, foremost sufficiently high flue gas temperatures.

    This work has identified parameters that effects foremost hydrogen-based combustion emission from the solid fuel boiler. This was achieved by evaluating historical data and by conducting tests during operation of the solid fuel boiler, which was planned and evaluated using a software called MODDE. Emission reducing measures and recommended ways to operate the boiler was then presented from the collected data.

    Practical measures including down-winding supply machinery of secondary air and replacement of urea injection showed no tendencies in reducing NOx emissions. However, complete shut down of one the furnaces produced at least 100 °C higher flue gas temperatures produced from the active furnace. Low NOx emissions was noted when secondary air was supplied from machinery with original speed. therefor, during stretched periods with low steam production, it's recommended that: Only one furnace should be active as steam producer, urea should be injected at its original placement in the flue gas chamber close the furnace and that secondary air should be supplied by machinery with original speed. Comparison test made in this work showed that this way of operating the solid fuel boiler could reduce NOx emissions with 45 % compared to mean NOx emissions at low steam production in July 2016.

  • 292.
    Larsson, Gustav
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Värmeleverans från pappers- och massabruk till sågverk2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Stenvalls Trä äger ett sågverk på Lövholmen i centrala Piteå. De har ett effektbehov på ca 10 MW värme för att torka virke i virkestorkar. Smurfit Kappa Kraftliner är ett integrerat pappers- och massabruk och även Piteås största producent av fjärrvärme. Fjärrvärme produceras främst med sekundärvärme, som är betraktat som spillvärme. Om fjärrvärmebehovet är stort används även primärvärme i form av ånga. Under vissa delar av året när fjärrvärmebehovet är lågt finns ett överskott av sekundärvärme. Stenvalls Trä är en tänkbar köpare av värme, men för att möjliggöra värmeleverans måste investeringar göras i form av en 3 km fjärrvärmekulvert, pump och värmeväxlare. För att undersöka konsekvenserna av en sammankoppling har en modell skapats i Excel som kan beräkna behovet av primärvärme för att ge rätt effekt och temperatur till Stenvalls Trä. Eftersom sågverket kräver hög temperatur måste en delmängd av flödet vara primärvärme. En undersökning har även utförts på sågverket för att fastställa effektbehovet till 10 MW och temperaturbehovet till 95°C. Värmen som levereras från Smurfit Kappa är 96°C och returen 80°C. Vid leverans vintertid när utetemperaturen är kallare än -10°C kommer all leverans ske med primärvärme. Turbinen som genererar el med ånga från biopannan är fullastad vintertid. Det innebär att primärvärme som används för leverans vid utetemperatur kallare än 0°C inte kommer ge ökad elproduktion. Vid högre utomhustemperaturer blir behovet av primärvärme lägre med bättre marginaler som följd, tack vare elproduktion och leverans av sekundärvärme. När det är olönsamt att leverera värme kan Stenvalls Trä använda sin egen biopanna. Möjligheterna för att det ska vara lönsamt att leverera värme vissa delar av året från Smurfit Kappa till Stenvalls Trä bedöms vara mycket goda.

  • 293.
    Larsson Isfelt, Niclas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utveckling av kabelfordon: Framtagning av konceptstudie för kabelfordon2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Within this project there is two parts; this thesis focuses on the construction of the attachment and the other part reported in another thesis focuses on the hydraulic components which is supposed to control the attachment and also feed the cable in and out.

     

    This project involves the construction of an attachment for mounting cable drums of varying sizes. The purpose is to develop a conceptual study for a custom made attachment that will be mounted on the back of the existing three point hitch on a JCB Fastrac 4220. The aim has been to provide an attachment that is of good user friendliness for operators and meets all the demands for operation.

     

    There will be dynamic loads on the gear, which will cause fatigue of the attachments structure. This has been counteracted by analyzing the stresses in the structure using FE analysis and placing reinforcements in the form of gussets or another beam profile to reduce stress concentrations. The final design has then been simulated for the different operating cases selected (DF). The simpler calculations such as shear stresses in the pins have been done manually, because it is a faster method compared to FEM, especially when there are several different sizes on the pins.

     

    The results show that the tension in the main support at DF1 and DF2 is close to the yield limit, which can be a problem at dynamic load. In the other cases, the stresses are much lower and approach the fatigue limit of the base material. In the welds that have poor fatigue properties, it cannot be concluded that there is endless life. When anlyzing the side support, the DF1-DF5 operating modes show stresses below the fatigue limit of the base material. When it comes to the welds, they have inferior fatigue properties which can cause cracking in the long run. The manual calculations resulted in a maximum von Mises stress of 446 MPa in the pin. With the steel 42CrMo4 chosen instead of the more common S355J2, the fatigue limit is well above the maximum von Mises stress of 446 MPa.

     

    The work resulted in a proposal for a attachment used for mounting cable drums according to the existing requirements. Before delivery to the customer it needs some more work to analyze all the imaginable scenarios and also verify that everything matches to the vehicle.

  • 294.
    Larsson, Johan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analys av fördelningssystem för bostadshus2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this project is to analyze earthing systems for houses. By practical measurements and theoretical analyzes consequences of possible faults, that can occur within the facility and in the low-voltage distribution network, is illustrated.  

    The reason for this project is that nowadays one has to arrange with a main equipotential bonding system for buildings. Apart from that, if necessary, bathrooms must be provided with a supplementary equipotential bonding system.

    The practical measurements verify that potential differences in facilities may be due to voltage drops in the PEN conductor between the origin of the electrical installation and the power transformer.

    Based on the theoretical analyzes of possible faults, it is considered that the requirement for  supplementary equipotential bonding systems for bathrooms in most cases can be questioned, when basic insulation, fault protection, residual current devise and main equipotential bonding system already provides an adequate level of protection.

    A PEN conductor loss may result in a situation where metallic parts attached to the equipotential bonding system starts working as earth electrodes. Equipotential bonding system may also increase the incidence of stray currents. If TN-C-S systems is provided with a local connection to earth a redundant system against PEN conductor loss is obtained. That is not the case for neutral conductor loss in TN-S systems with a local connection to earth. If district heating pipes is supplied with insulated flanges it prevents stray currents and foreign potential to be spread in the district heating network.

  • 295.
    Larsson, Simon
    Umeå University, Faculty of Science and Technology, Umeå Institute of Design.
    Handling of Air Baggage2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The airport staff working with baggage handling have a tough job, lifting up to 15 tones/day per person. Every bag gets lifted manually 6 times on its way from check in to the baggage drop band, which is why the work is very repetitive and often leads to back, shoulder and other kinds of physical problems. My concept, the ABT (Autonomous Baggage Train), removes 4 of these manual lifting moments and also shortens the waiting time for the arriving passengers, reduces the wear on both baggage and the airport´s baggage bands and contributes to a safer working environment.

  • 296.
    Larsson, Sylvia H.
    et al.
    Swedish University of Agricultural Sciences, Unit of Biomass Technology and Chemistry.
    Rudolfsson, Magnus
    Swedish University of Agricultural Sciences, Unit of Biomass Technology and Chemistry.
    Nordwaeger, Martin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Olofsson, Ingemar
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Samuelsson, Robert
    Swedish University of Agricultural Sciences, Unit of Biomass Technology and Chemistry.
    Effects of moisture content, torrefaction temperature, and die temperature in pilot scale pelletizing of torrefied Norway spruce2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 102, p. 827-832Article in journal (Refereed)
    Abstract [en]

    Pilot scale pelletizing of torrefied Norway spruce was performed in a factorial design with controlled factors at two levels: material moisture content (11% and 15%) and torrefaction temperature (270 and 300 °C), and die temperature as an uncontrolled factor (60–105 °C). Compared to commercial wood pellets, produced pellets had comparable bulk densities (630–710 kg/m3) but lower pellet durability (80–90%). Energy consumption for pelletizing of torrefied materials was approximately 100% higher than for softwood pelletizing, despite using a much shorter die channel length (35 vs. 55 mm:s), and the amounts of fines were high (10–30%). Die temperature showed a strong positive correlation with pellet production rate. Material moisture content had little influence on pellet quality and production rate, but addition of water created handling problems due to bad flow behavior.

  • 297.
    Larsson, Tommy
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Determining the viscous splash losses in the housing of a hydraulic motor through CFD-simulations: A master thesis in collaboration with Bosch-Rexroth in Mellansel AB2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    One possible way of solving future energy shortages is by the optimization of our current energy consumption. These optimizations must span all possible fields of consumption. In the mechanical field radial piston hydraulic motors may show some margin of improvement. The radial piston hydraulic motor is driven by a pressure difference in hydraulic oil. These motors are commonly found in heavy industrial equipments such as drills and conveyor belts. The advantage with these motors in comparison with electric motors is the high torque and ability to absorb shock loads that may cause damage to electrical motors.

    The effectiveness of these motors are determined both by the motor and by the drive system as a whole consisting of hydraulic pump driven by a electric motor, hydraulic hoses, motor and possible external coolers. If the effectiveness of the motor is low the whole drive system will be affected thus amplifying the total losses. The losses in the motor can be both mechanical and derived to the viscosity of the oil. One region in the motor where there are viscous losses are in the housing. The housing is filled with oil, that both aids in the cooling and acts as a lubricant for the motor. Pistons and rollers are some of the components found in the housing. These components rotates around the centre line axis while having a pulsating radial motion following a cam ring. This rotating and pulsating motion will push oil in and out of a volume between two consecutive pistons and rollers. This will create viscous losses and regions with a enhanced risk of cavitation.

    This study investigates if the flow of oil in the housing can be simulated accurately. The study also examine what are the main problems regarding the flow of oil in the housing and the factors affecting the size of the viscous losses. The study also examines the correlation between viscosity and viscous losses. Finally two different optimizations with the intention of decreasing the viscous losses are compared.

    The study found that the majority of the viscous losses in the housing can be derived to the flow of hydraulic oil in and out of the volume between two consecutive pistons and rollers. The oil will pass a sharp edge around the cylinder block and a narrow passage under the spacing between the cylinder rows in a two cam ring configured motor. This will create regions with a enhanced velocity and risk of cavitation. The stroke of the motor will greatly affect the effectiveness of the motor especially at a high rotational speed. The viscous losses will be transformed into internal energy, heat, thus increasing the temperature of the oil. A increased temperature will decrease the viscosity and the viscous losses. The viscous losses will vary with 17 % if the viscosity is varied between 20 and 100 cSt. The developed model is not sufficient to determine the viscous losses accurately since the geometry had to be considerably simplified, but can act as a way of comparing different optimizations of the motor. The viscous losses can be decreased with 25 % in the CCe motor at 150 rpm by milling material of the cylinder block between the piston holes. This is an expensive optimization and needs to be justified from a cost-benefit perspective.

    The full text will be freely available from 2022-06-01 17:51
  • 298.
    Ledin, Niclas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    The effects of processing conditions on crystallization of rr-P3HT for use in organic electronic devices.2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 299.
    Lee, Nicky
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Spränggenerator för rengöring av överhettare i avfallspanna: Utredning av drifterfarenheter och ekonomi i Umeå Energis kraftvärmeanläggning Dåva 12019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of this report was to evaluate a shock pulse generator installed at Dåva 1, the waste-fired combined heat and power (CHP) plant at Umeå Energi AB, located about 9 km northeast of Umeå. The study deals with the subject based on both technical aspects, in terms of operating experience and performance. Financial aspects, regarding repayment time and operating costs. With these results, an investment for a shock pulse generator has been discussed. Furthermore, proposals for improvements or combinations with ammonium sulphate should be discussed in order to prevent corrosion, in particular chlorine-induced corrosion.

    With the data logging program (ABB 800xa Smart Client), it was possible to study temperature trends and profiles at the superheaters. With these data, calculations have been performed to obtain a heat transfer coefficient (UA-value). The UA-value describes how the heat transfer changes over time and is therefore a measure of the degree of coating formation, and how the shock pulse generator influences this. Comparisons have been made for periods before and after the installation of the shock pulse generator. The study has included several interviews with the operation and maintenance staff concerning costs and experiences, to perform an economic calculation.

     

    The results show that the shock pulse generator have had a positive effect with an increase in the UA mean value by 7%. With reduced growth of deposits with the shock pulse generator, there are possibilities to reduce operating and maintenance costs. An improvement in the efficiency of the shock pulse generator could also have been achieved by increasing the frequency of explosion during periods where coating formation occurs. A future method could be to combine the UA-value with the shock pulse generator to create an intelligent soot-blowing system.

     

    The payback period for the installed shock pulse generator is estimated to be 5.7 years with a saving of SEK 385,000/year. For the assessment of an extra shock pulse generator, the evaluation indicate that it would probably not be as profitable as the present shock pulse generator.

    A minor literature study was also performed concerning deposit formation on superheater tubes and the effects of addition of ammonium sulphate. According to previous studies, deposits with a higher content of sulfur than chlorine are formed when using such additive, which causes deposits to become less corrosive and more porous, which makes them easier to be removed. This can be interesting for Dåva 1 and can be a suggestion for further investigation.

  • 300.
    Leonarde, Alexander
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Generationsskifte av vindkraftverk2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
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