du.sePublications
Change search
Refine search result
1234567 101 - 150 of 1341
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • chicago-author-date
  • chicago-note-bibliography
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 101.
    Bexell, Ulf
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Olsson, Mikael
    Dalarna University, School of Technology and Business Studies, Material Science.
    Time-of-Flight SIMS Characterization of Hydrolysed Organofunctional and Non-Organofunctional Silanes Deposited on Al, Zn and Al-43.4Zn-1.6Si Alloy-Coated Steel2003In: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 35, no 11, p. 880-887Article in journal (Refereed)
  • 102.
    Bexell, Ulf
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Olsson, Mikael
    Dalarna University, School of Technology and Business Studies, Material Science.
    Jani, Simon
    AB Sandvik Materials Technology, Sandviken, Sweden.
    Lundberg, Mats W.
    AB Sandvik Materials Technology, Sandviken, Sweden.
    Initial oxidation of ferritic interconnect steel, effect due to a thin ceria coating2012In: European Fuel Cell Forum 2012 - Proceedings (memory stick), 2012Conference paper (Other academic)
    Abstract [en]

    Today there exist many ferritic stainless steel grades with a chemical composition speciallydesigned to be used as interconnects in solid oxide fuel cell applications in a temperatureinterval of 650-850°C. The steels have good high temperature mechanical properties andcorrosion resistance as well as good electron conductivity in the formed chromium oxidescale.One way to substantially decrease the high temperature degradation of the interconnectsteel i.e. improve properties such as increased surface conductivity and decreasedoxidation and chromium evaporation is to coat the interconnect steel with suitablecoatings. Today it is well known that a thin cobalt coating hinders chromium evaporationand a ceria coating lowers the oxidation rate at high temperature. Thus, by coating theinterconnect steel the properties are improved to an extent that it should be possible to usea cheaper standard steel, e.g. AISI 441, as substrate for the coatings.In this study the ferritic stainless steel alloys Sandvik Sanergy HT and AISI 441 is oxidizedin laboratory air at temperatures at 750°C, 800°C and 850°C. The results show that a welladhered oxide scale of a complex layered structure is formed with significant amounts ofMn, Fe, Cr and Ti in the oxide scale. A Ce coating significantly reduces the growth rate ofthe oxide scale. The lower Cr content in the AISI 441 alloy does not affect the initial hightemperature corrosion properties when coated with Ce. Also, the results demonstrate theusefulness of ToF-SIMS depth profiling for characterisation of the initial stages of oxidationof SOFC materials.

  • 103.
    Bexell, Ulf
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Olsson, Mikael
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Lundberg, M.
    High temperature oxidation of plastically deformed ferritic interconnect steel2011In: ECS Transactions, ISSN 1938-5862, E-ISSN 1938-6737, Vol. 35, no 1, p. 2463-2470Article in journal (Refereed)
    Abstract [en]

    In this study, thin sheets of a 22% Cr ferritic steel, Sandvik Sanergy HT has been coated with a thin metallic cobalt film. Samples of the coated steel sheet were exposed to two different forming experiments simulating different aspects of sheet metal forming and post high temperature oxidation. The results show that the metallic cobalt film cracks when the steel sheet is subjected to biaxial straining but that the cracks heal at high temperature. Material subjected to modified scratch testing i.e. simulating the contact between sheet metal and forming tool will oxidize in the same manner as non-scratched material. Also, from high temperature corrosion point of view there is no difference between materials formed under lubricated or dry conditions when oxidized. However, from a tribological point of view a lubricated contact situation is preferred.

  • 104.
    Bexell, Ulf
    et al.
    Dalarna University, School of Technology and Business Studies, Material Science.
    Stanciu, V.
    Warnicke, P.
    Östh, M.
    Svedlindh, P.
    ToF-SIMS depth profiling of (Ga,Mn)As capped with amorphous arsenic: effects of annealing time2006In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 252, no 19, p. 7252-7254Article in journal (Refereed)
    Abstract [en]

    The influence of annealing time on an amorphous As cap layer and the depth distribution of Mn atoms have been investigated. The results show that a 1600 Å thick As cap layer is completely desorbed after 3 h of annealing time. The depth distributions of Mn indicate that interstitial Mn atoms have diffused to the outer surface and being passivated. The thickness of the Mn passivation layer was around 90 Å.

  • 105. Birchall, Sarah
    et al.
    Gustafsson, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH.
    Wallis, Ian
    Dipasquale, Chiara
    Bellini, Alessandro
    Fedrizzi, Roberto
    Survery and simulation of energy use in the European building stock2016Conference paper (Refereed)
    Abstract [en]

    the work towards increased energy efficiency. In order to plan and perform effective energy renovation of the buildings, it is necessary to have adequate information on the current status of the buildings in terms of architectural features and energy needs. Unfortunately, the official statistics do not include all of the needed information for the whole building stock.

     

    This paper aims to fill the gaps in the statistics by gathering data from studies, projects and national energy agencies, and by calibrating TRNSYS models against the existing data to complete missing energy demand data, for countries with similar climate, through simulation. The survey was limited to residential and office buildings in the EU member states (before July 2013). This work was carried out as part of the EU FP7 project iNSPiRe.

     

    The building stock survey revealed over 70% of the residential and office floor area is concentrated in the six most populated countries. The total energy consumption in the residential sector is 14 times that of the office sector. In the residential sector, single family houses represent 60% of the heated floor area, albeit with different share in the different countries, indicating that retrofit solutions cannot be focused only on multi-family houses.

     

    The simulation results indicate that residential buildings in central and southern European countries are not always heated to 20 °C, but are kept at a lower temperature during at least part of the day. Improving the energy performance of these houses through renovation could allow the occupants to increase the room temperature and improve their thermal comfort, even though the potential for energy savings would then be reduced.

  • 106.
    Biswas, Rubel
    et al.
    BRAC Univ, Dept Comp Sci & Engn, Dhaka, Bangladesh..
    Fleyeh, Hasan
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Mostakim, Moin
    BRAC Univ, Dept Comp Sci & Engn, Dhaka, Bangladesh..
    Detection and classification of speed limit traffic signs2014In: 2014 World Congree on Computer Applications and Information Systems (WCCAIS), 2014Conference paper (Refereed)
    Abstract [en]

    This paper presents a novel traffic sign recognition system which can aid in the development of Intelligent Speed Adaptation. This system is based on extracting the speed limit sign from the traffic scene by Circular Hough Transform (CHT) with the aid of colour and non-colour information of the traffic sign. The digits of the speed limit sign are then extracted and classified using SVM classifier which is trained for this purpose. In general, the system detects the prohibitory traffic sign in the first place, specifies whether the detected sign is a speed limit sign, and then determines the allowed speed in case the detected sign is a speed limit sign. The SVM classifier was trained with 270 images which were collected in different light conditions. To check the robustness of this system, it was tested against 210 images which contain 213 speed limit traffic sign and 288 Non-Speed limit signs. It was found that the accuracy of recognition was 98% which indicates clearly the high robustness targeted by this system.

  • 107.
    Björk, Johan
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Utveckling av programvara för inrapportering av vägstatus och utrustning längs med vägar2010Independent thesis Basic level (degree of Bachelor)Student thesis
  • 108.
    Björling, Jimmy
    Dalarna University, School of Technology and Business Studies, Construction.
    Digitala ritningar2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In todays building industry there is a need for using of digital construction

    drawings. The purpose of this report is to inquire into, the will of the employers in

    Byggpartners to use digital drawings in their daily work and if the different

    drawing systems distinguishes from each other

    The method selections in this report is survey, semi structured interviews, and

    time experiments. The studies show that the new digital technique worked well

    and gave reliable and useful results. One important conclusion of this project is

    that digital drawings are more time saving comparing to paper drawings. By

    reviewing the use of digital drawings, one can easily prevent some problems

    which might otherwise be associated with the opposition of digital drawings out

    in the building place.

  • 109.
    Blackman, Corey
    Dalarna University, School of Technology and Business Studies, Energy Technology. Mälardalens högskola.
    Evaluation of a thermally driven heat pump for solar heating and cooling applications2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Exploiting solar energy technology for both heating and cooling purposes has the potential of meeting an appreciable portion of the energy demand in buildings throughout the year. By developing an integrated, multi-purpose solar energy system, that can operate all twelve months of the year, a high utilisation factor can be achieved which translates to more economical systems. However, there are still some techno-economic barriers to the general commercialisation and market penetration of such technologies. These are associated with high system and installation costs, significant system complexity, and lack of knowledge of system implementation and expected performance. A sorption heat pump module that can be integrated directly into a solar thermal collector has thus been developed in order to tackle the aforementioned market barriers. This has been designed for the development of cost-effective pre-engineered solar energy system kits that can provide both heating and cooling.

    This thesis summarises the characterisation studies of the operation of individual sorption modules, sorption module integrated solar collectors and a full solar heating and cooling system employing sorption module integrated collectors. Key performance indicators for the individual sorption modules showed cooling delivery for 6 hours at an average power of 40 W and a temperature lift of 21°C. Upon integration of the sorption modules into a solar collector, measured solar radiation energy to cooling energy conversion efficiencies (solar cooling COP) were between 0.10 and 0.25 with average cooling powers between 90 and 200 W/m2 collector aperture area. Further investigations of the sorption module integrated collectors implementation in a full solar heating and cooling system yielded electrical cooling COP ranging from 1.7 to 12.6 with an average of 10.6 for the test period.

    Additionally, simulations were performed to determine system energy and cost saving potential for various system sizes over a full year of operation for a 140 m2 single-family dwelling located in Madrid, Spain. Simulations yielded an annual solar fraction of 42% and potential cost savings of €386 per annum for a solar heating and cooling installation employing 20m2 of sorption integrated collectors.

  • 110.
    Blackman, Corey
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Experimental Evaluation and Concept Demonstration of a Novel Modular Gas-Driven Sorption Heat Pump2017Conference paper (Refereed)
    Abstract [en]

    Gas-driven sorption heat pumps (GDSHPs) exhibit possibilities in the reduction of energy use and environmental impact of heating systems that utilise natural gas. By utilising renewable thermal energy from the environment, that is, air, ground or water sources, significant reduction of primary energy use can be achieved. However, high cost, low coefficient of performance (COP) and large volume per unit thermal power produced have limited the proliferation of GDSHPs. In this work, exploiting the benefits of reversible chemical reactions in sorption systems, with no internal moving parts, noise, vibration and maintenance-free reactor design, two novel modular prototype sorption components were developed and evaluated experimentally. They were designed to operate as part of an intermittent cycle GDSHP to deliver heat directly to a load or to a stratified hot water store. Prototype 1 was an ammonia-salt basic sorption unit while prototype 2 was an ammonia-salt resorption unit both employing proprietary composite sorbent materials. Test results showed that the prototype 2 reactor produced a specific heating capacity of 46 W/litre at a temperature lift of 50°C yielding a COP of 1.38. Prototype 1 demonstrated higher heating capacity of 73 W/litre at a temperature lift of 70°C but exhibited lower COP of 1.10. Given its higher COP but lower temperature lift, prototype 2 could be employed in a GDSHP designed for moderate heating demands or where a ground source heat exchanger is employed as the low temperature heat source. In the case where a higher temperature lift is required, for example, for an air-source GDSHP unit then the prototype 1 design would be more applicable.

  • 111.
    Blackman, Corey
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Study of Optimal Sizing for Residential Sorption Heat Pump System2017Conference paper (Refereed)
    Abstract [en]

    Gas-driven sorption heat pumps (GDSHP) show significant potential to reduce primary energy use, associated emissions and energy costs for space heating and domestic hot water (DHW) production in residential applications. In this study a bivalent system was considered, characterised by the integration of a novel modular sorption heat pump component and a condensing boiler. The modular heat pump component, or sorption module (SM), has been developed in two types: Type A and Type B, either of which could be integrated into a bivalent GDSHP system. The Type A sorption module had a functioning principle based on a solid chemisorption cycle, while Type B operates under a resorption cycle. To investigate the applicability of each SM type, a bivalent GDSHP system with a Type A SM (GDSHPA) and one with a Type B SM (GDSHPB) were evaluated. Simulations of year-round space heating loads for two single family houses, one in New York and the other Minnesota, were carried out and the seasonal gas coefficient of performance (SGCOP) for each GDSHP system calculated. The impact of the ratio of the design heating capacity of the SM compared to the peak heating capacity of the bivalent GDSHP was studied. Results show that SGCOP was not significantly affected for SM design heating capacity ratios greater than 66% of the peak GDSHPA design capacity in Minnesota, and 21% for GDSHPB. In New York, the ratios were 55% and 35% for GDSHPA and GDSHPB respectively.

  • 112.
    Blackman, Corey
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Test Platform and Methodology for Model Parameter Identification of Sorption Heat Pump Modules2017Conference paper (Refereed)
    Abstract [en]

    Sorption heat pumps are employed in various heat-driven cooling and heat pumping applications. These heat pumps may be driven by solar energy, natural gas, biogas, geothermal energy or waste heat. Given that a plethora of heat sources and sorption materials can be exploited for different applications, various sorption heat pump modules have been developed. The sorption modules are pre-engineered sorption components for increased ease of sorption system development, improved cost effectiveness and reduced system complexity for various applications. However, in the design of sorption modules, component and system modelling and simulation are useful in the process of determining the optimal candidate of several possible sorption working couples for a given application. A test platform has been developed and a test methodology devised for the rapid characterisation of the transient behaviour of the sorption modules. The testing apparatus was used to derive various model parameters to be used for validation of a dynamic sorption module component model. The test method was analogous to that employed for dynamic testing and performance modelling of electrochemical accumulators (i.e. electric batteries) given the similarities between them and sorption modules (also known as thermochemical accumulators). The model parameter identification was based on various heating and cooling power performance parameters as a function of state of charge (SoC) of the sorption modules. A 7-step procedure was used to characterise the performance of the sorption modules based on experimental data. A reference performance for charge and discharge of the sorption modules was measured followed by several measurements at ‘off-reference’ conditions. Performance curves for ‘off-reference’ conditions were then correlated to reference conditions to generate performance curves that describe the transient cooling and heating power delivery of the sorption module at any point within the test range. Results showed that the discharge performance of the sorption modules could be predicted within a reasonable margin of error with a test run sequence of 39 cycles.

  • 113.
    Blackman, Corey
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. Mälardalen University.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Experimental evaluation of a novel absorption heat pump module for solar cooling applications2015In: Science and Technology for the Built Environment, ISSN 2374-4731, Vol. 21, no 3, p. 323-331Article in journal (Refereed)
    Abstract [en]

    Given the environmental benefits of utilizing free thermal energy sources, such as waste heat and solar energy for cooling purposes, many developments have come about in thermally driven cooling. However, there are still some barriers to the general commercialization and market penetration of such technologies that are associated with system and installation costs, complexity, and maintenance. In efforts to overcome these limitations, a novel absorption heat pump module has been developed and tested. The module comprises a fully encapsulated sorption tube containing hygroscopic salt sorbent and water as a refrigerant, sealed under vacuum, and within which there are no moving parts. The absorption module consists of two main components, one that alternately functions as an absorber or generator and other that alternates between the roles of evaporator and condenser. The module therefore operates cyclically between a cooling delivery phase and a regeneration phase. Each module has a significant energy storage capacity with cooling delivery phases ranging from 6-10 h in length with temperature lifts between 16 degrees C and 25 degrees C. The modules are optimized for integration directly into a solar thermal collector, for roof or facade installation, for daytime regeneration and night-time cooling delivery. Collector integrated modules would be completely modular maintenance-free absorption heat pumps with similar installation requirements to standard solar thermal collectors. This article describes the test method and performance characteristics of the individual absorption modules.

  • 114.
    Blackman, Corey
    et al.
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology. Mälardalen University.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Hallström, Olof
    Mälardalen University.
    Demonstration of Solar Heating and Cooling System using Sorption Integrated Solar Thermal Collectors2014In: EuroSun 2014 / ISES Conference Proceedings (2014), ISES , 2014Conference paper (Refereed)
    Abstract [en]

    Producing cost-competitive small and medium-sized solar cooling systems is currently a significant challenge. Due to system complexity, extensive engineering, design and equipment costs; the installation costs of solar thermal cooling systems are prohibitively high. In efforts to overcome these limitations, a novel sorption heat pump module has been developed and directly integrated into a solar thermal collector. The module comprises a fully encapsulated sorption tube containing hygroscopic salt sorbent and water as a refrigerant, sealed under vacuum with no moving parts. A 5.6m2 aperture area outdoor laboratory-scale system of sorption module integrated solar collectors was installed in Stockholm, Sweden and evaluated under constant re-cooling and chilled fluid return temperatures in order to assess collector performance. Measured average solar cooling COP was 0.19 with average cooling powers between 120 and 200 Wm-2 collector aperture area. It was observed that average collector cooling power is constant at daily insolation levels above 3.6 kWhm-2 with the cooling energy produced being proportional to solar insolation. For full evaluation of an integrated sorption collector solar heating and cooling system, under the umbrella of a European Union project for technological innovation, a 180 m2 large-scale demonstration system has been installed in Karlstad, Sweden. Results from the installation commissioned in summer 2014 with non-optimised control strategies showed average electrical COP of 10.6 and average cooling powers between 140 and 250 Wm-2 collector aperture area. Optimisation of control strategies, heat transfer fluid flows through the collectors and electrical COP will be carried out in autumn 2014.

  • 115.
    Blackman, Corey
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Thorin, Eva
    Techno-economic evaluation of solar-assisted heating and cooling systems with sorption module integrated solar collectors2015In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 70, p. 409-417Article in journal (Refereed)
    Abstract [en]

    Currently the use of solar energy for heating and cooling isn't widespread. In order to reduce primary energy consumption in the built environment along with improving the thermal performance of the current building stock, retrofit solutions are required to utilise renewable energy. Using solar energy to reduce primary energy consumption is seen as a possible solution. With the precipitous fall in the prices of crystalline solar photovoltaic modules, utilising this technology to reduce electrical energy consumption for cooling is an attractive solution. Recently, a sorption module integrated collector has been developed in order to improve cost-effectiveness and simplify solar thermal heating and cooling systems. A techno-economic analysis has been performed to evaluate solar photovoltaic cooling and solar thermal cooling systems for residential renewable energy retrofit. The analysis is based on potential energy and cost savings according to simulated heating and cooling loads under climatic conditions of Madrid, Spain. Simplified models were used to determine heating and cooling demands and the solar energy contribution to heating and cooling loads. Additionally, given the sorption collector's unique capacity to store solar energy thermally and provide cooling at night an analysis has been carried out to identify the combined benefit of solar-assisted heating and cooling via photovoltaics during the day and solar sorption at night. For system sizes between 5m(2) and 20m(2) solar fractions between 16% and 64% could be achieved which translated to annual energy cost savings between (sic)153 to (sic)615. (C) 2015 The Authors. Published by Elsevier Ltd.

  • 116.
    Blackman, Corey
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. SaltX Technology, Hägersten, Stockholm; Mälardalen University.
    Gluesenkamp, Kyle R.
    Malhotra, Mini
    Yang, Zhiyao
    Study of optimal sizing for residential sorption heat pump system2019In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 150, no 5, p. 421-432Article in journal (Refereed)
    Abstract [en]

    Gas-driven sorption heat pumps (GDSHP) show significant potential to reduce primary energy use, associated emissions and energy costs for space heating and domestic hot water production in residential applications. This study considered a bivalent heating system consisting of a sorption heat pump and a condensing boiler, and focuses on the optimal heating capacity of each of these components relative to each other. Two bivalent systems were considered: one based on a solid chemisorption cycle (GDSHPA), and one based on a resorption cycle (GDSHPB). Simulations of year-round space heating loads for two single family houses, one in New York and the other Minnesota, were carried out and the seasonal gas coefficient of performance (SGCOP) calculated. The sorption heat pump’s design heating capacity as a fraction of the bivalent system’s total heating capacity was varied from 0 to 100%. Results show that SGCOP was effectively constant for sorption heat pump design capacity greater than 41% of the peak bivalent GDSHPA design capacity in Minnesota, and 32% for GDSHPB. In New York, these values were 42% and 34% for GDSHPA and GDSHPB respectively. Payback period was also evaluated based on postulated sorption heat pump component costs. The fastest payback was achieved with sorption heat pump design capacity between 22–44%.

  • 117.
    Blessborn, Daniel
    et al.
    Dalarna University, School of Technology and Business Studies, Chemical Engineering.
    Römsing, Susanne
    Dalarna University, School of Technology and Business Studies, Chemical Engineering.
    A semi-quantitative screening method to identify some of the most commonly used antimalarial drugs2009In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 14, p. 130-130Article in journal (Other academic)
  • 118.
    Blessborn, Daniel
    et al.
    Dalarna University, School of Technology and Business Studies, Chemical Engineering.
    Römsing, Susanne
    Dalarna University, School of Technology and Business Studies, Chemical Engineering.
    Annerberg, Anna
    Sundquist, Daniel
    Björkman, Anders
    Lindegårdh, Niklas
    Bergqvist, Yngve
    Dalarna University, School of Technology and Business Studies, Chemical Engineering.
    Development and validation of an automated solid-phase extraction and liquid chromatographic method for determination of lumefantrine in capillary blood on sampling paper.2007In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 45, no 2, p. 282-287Article in journal (Refereed)
    Abstract [en]

    A bioanalytical method for the determination of lumefantrine in 100 µl blood applied onto sampling paper, by solid-phase extraction and liquid chromatography, has been developed and validated. Whatman 31 ET Chr sampling paper was pre-treated with 0.75 M tartaric acid before sampling capillary blood to enable a high recovery of lumefantrine. Lumefantrine was extracted from the sampling paper, then further purified using solid-phase extraction and finally quantified with HPLC. The between-day variation was below 10% over the range 0.4–25 µM. The lower limit of quantification was 0.25 µM in 100 µl capillary blood. No decrease in lumefantrine concentration in dried blood spot is seen after 4 months storage at 22 °C. The method was also evaluated in field samples from patients in Tanzania after treatment with lumefantrine/artemether. Lumefantrine could be estimated accurately enough to assess bioavailability and treatment compliance on day 7 (i.e. 4 days after the last dose) after a standard regimen with the lumefantrine/artemether combination.

  • 119.
    Blessborn, Daniel
    et al.
    Dalarna University, School of Technology and Business Studies, Chemical Engineering.
    Römsing, Susanne
    Dalarna University, School of Education, Health and Social Studies, Chemistry.
    Bergqvist, Yngve
    Dalarna University, School of Education, Health and Social Studies, Medical Science.
    Lindegardh, Niklas
    Assay for screening for six antimalarial drugs and one metabolite using dried blood spot sampling, sequential extraction and ion-trap detection2010In: Bioanalysis, ISSN 1757-6180, E-ISSN 1757-6199, Vol. 2, no 11, p. 1839-1847Article in journal (Refereed)
    Abstract [en]

    Background: More parasites are becoming resistant to antimalarial drugs, and in many areas a change in first-line drug treatment is necessary. The aim of the developed assay is to help determine drug use in these areas and also to be a complement to interviewing patients, which will increase reliability of surveys.

    Results: This assay detects quinine, mefloquine, sulfadoxine, pyrimethamine, lumefantrine, chloroquine and its metabolite desethylchloroquine in a 100-mu l dried blood spot. Most of the drugs also have long half-lives that make them detectable at least 7 days after administration. The drugs are extracted from the dried blood spot with sequential extraction (due to the big differences in physicochemical properties), solid-phase extraction is used as sample clean-up and separation is performed with gradient-LC with MS ion-trap detection.

    Conclusion: Detection limits (S/N > 5:1) at 50 ng/ml or better were achieved for all drugs except lumefantrine (200 ng/ml), and thus can be used to determine patient compliance. A major advantage of using the ion-trap MS it that it will be possible to go back into the data and look for other drugs as needed.

  • 120.
    Block, Matteus
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Johansson, Rikard
    Dalarna University, School of Technology and Business Studies, Construction.
    Undersökning av ny metod för analys av konstruktionsanläggningar2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Sweco Civil är ett företag som bland annat arbetar med att besikta broar åt Trafikverket. När en besiktning av en bro görs vill man ta reda på om den håller för trafikflödet. För att kunna räkna ut om den håller behövs kännedom om brons armeringstyp, cc-mått samt tjocklek i underkant av bron och i brons stöd. Idag bilar man fram armeringen i betongen och detta tar både tid och skadar bron. I denna rapport har en ny metod för att ta reda på armeringen i betongen testats. Den nya metoden består av att använda sig av en maskin vid namn C-thrue ifrån IDS georadar. Maskinen använder sig av elektrisk polarisation för att hitta armeringen i betongen. Det maskinen scannar fram projekteras på en bild som sedan tolkas. Maskinen prövades först på en bro där armerings ritningarna analyserades innan mätningarna. Efter att mätarna visste hur mätningarna skulle tolkas prövades maskinen på två andra broar där mätarna inte fick information från armeringsritningarna förens efter mätningarna. Maskinen fungerade bra för att mäta cc-mått på mindre broar men när broarna blev större och mer armering var placerad i underkant av bron blev mätresultaten för svåra att tolka för att kunna få ut ett cc-mått. Maskinen kunde inte heller med precision visa armeringens diameter eller typ.

  • 121.
    Blomberg, J
    et al.
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Persson, B
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Blomberg, A
    Effects of semi-isostatic densification of wood on the variation in strength properties with density2005In: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 39, no 5, p. 339-350Article in journal (Refereed)
    Abstract [en]

    The variation in strength properties with density was compared between semi-isostatically densified and non-densified wood. Strength properties were compared with published data from earlier studies using other methods for densification. Small clear specimens of eight species were analysed for compression strength in axial, radial and tangential direction, three-point bending and Brinell hardness. After densification, all tested strength properties increased with density, but especially strength perpendicular to grain became lower than expected from the density of non-densified wood. Strength of densified wood relative to what could be expected for non-densified wood of similar density was denoted as `strength potential index'. For axial compression strength and bending strength, strength potential index of individual wood species varied between 0.7 and 1.0, i.e. densified wood is slightly weaker than what could be expected from its density. Strength potential index was lower for properties much determined by strength perpendicular to grain. In radial direction, densified wood was rubbery with low modulus of elasticity and nearly no proportional limit or modulus of rupture. Generally, wood was apparently weakened in proportion to the degree of compression in respective direction. Strength potential index also increased with increasing original density of the species.

  • 122. Blomberg, Jonas
    et al.
    Persson, Bengt
    Dalarna University, School of Technology and Business Studies, Material Science.
    Bexell, Ulf
    Dalarna University, School of Technology and Business Studies, Material Science.
    Effects of semi-isostatic densification on anatomy and cell-shape recovery on soaking2006In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 60, no 3, p. 322-331Article in journal (Refereed)
    Abstract [en]

    Images obtained by scanning electron microscopy (SEM) helped to clarify the question as to how anatomy influences the deformation on compression and the spring-back of densified wood on water soaking. Transverse sections of Norway spruce (Picea abies), Scots pine (Pinus sylvestris), black alder (Alnus glutinosa), Swedish aspen (Populus tremula), European birch (Betula pubescens), European beech (Fagus sylvatica) and pedunculate oak (Quercus robur) were studied. Wood is reinforced with rays in the radial direction and with dense latewood in the tangential direction. When strained radially, rays buckle or tilt tangentially. Softwoods were mainly compressed radially, owing to low number of rays and since latewood is much denser than earlywood. The diffuse-porous hardwoods with low density variation between latewood and earlywood were mainly deformed tangentially, except birch, which has high density at the annual ring border and is mainly compressed radially. The ring-porous hardwoods were relatively equally deformed in the radial and tangential directions because of the high number of rays and high latewood density. Moisture-induced spring-back (shape recovery) was proportional to the degree of compression. Rays remained deformed, which also influenced the surrounding wood. Longitudinal wood cells almost resumed their original shape. Wood with low density and a low degree of compression showed the highest structural recovery. Shearing deformation was particularly pronounced and permanent in woods with high strength anisotropy. Thin-walled and sheared cells, such as earlywood in softwood, tended to crack on compression. Cracks usually stopped at the middle lamella and had a lesser influence on strength properties than for lumen-to-lumen cracks.

  • 123.
    Blomqvist, Stina
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Helgesson, Robin
    Dalarna University, School of Technology and Business Studies, Construction.
    Framtagning av yttervägg för småhus: En analys med hänsyn till kommande energikrav2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today is the specific requirements for the building’s energy use in new buildnings. These requirements come under the EU directive to be tightened firmly to the year 2020. This work was the basis of an interpretation of the coming energy requirements, 2020 requirements, designing a new energy-efficient exterior wall construction. This has been done with Fiskarhedenvillan and the construction has been valued in terms of material cost, assembly and the square meter price.

    By calculations and fact finding, demonstrated how energy in small houses could be reduced by replacing the insulating material to a material with lower heat conductivity. The method was to interpret the coming energy requirements and analyze Fiskarhedenvillan current wall construction. Next, search for information and facts about various insulation materials and then design a new proposal on the exterior wall construction.

    The outer wall construction is a crucial factor for the building envelope energy efficiency. Because Fiskarhedenvillan chosen to focus only on the outer wall, this work is delimited to that part of the building envelope.

    An important conclusion of this work is that the 2020 objectives can be met by improving the exterior wall construction and that it is possible to make a design that meets the requirements in entire Sweden

  • 124.
    Bois, Maria
    Dalarna University, School of Technology and Business Studies, Graphic Arts Technology.
    Skapande av ny webbplats till orienteringsklubben HJS Vansbro OK2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This assignment was made in cooperation with HJS-Vansbro OK, who needed a new website. The previous website was an IdrottOnline-site which appeared outdated, unattractive and not very user friendly. They wished for a new website, where the members easily could write news- and training posts.

    This assignment started with a meeting with the webmaster of the club and after that an overview of the current knowledge and where other teams in Dalarna had their website. Two surveys were sent to the members. In the first they answered questions about the previous website, and in the second questions about the new design suggestions, that were based on the answers from the first survey and on modern web design principles. After that a user test was performed and the problems that arose were then corrected.

    This assignment resulted in an almost completed website. It still lacked some information and minor adjustments, but overall, I feel pleased with the resul

  • 125.
    Borg, Johan
    et al.
    KTH.
    Lantz, Ann
    KTH.
    Gulliksen, Jan
    KTH.
    Accessibility to electronic communication for people with cognitive disabilities: a systematic search and review of empirical evidence2015In: Universal Access in the Information Society, ISSN 1615-5289, E-ISSN 1615-5297, Vol. 14, no 4, p. 547-562Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to identify and synthesize measures for accessibility to electronic communication for people with cognitive disabilities by seeking answers to the following research questions: What measures to make electronic communication accessible to people with cognitive disabilities are evaluated and reported in the scientific literature? What documented effects do these measures have? Empirical studies describing and assessing cognitive accessibility measures were identified by searches of 13 databases. Data were extracted and methodological quality was assessed. Findings were analyzed and recommendations for practice and research were made. Twenty-nine articles with considerable variations in studied accessibility measures, diagnoses, methods, outcome measures, and quality were included. They address the use of Internet, e-mail, telephone, chat, television, multimedia interfaces, texts and pictures, operation of equipment, and entering of information. Although thin, the current evidence base indicates that the accessibility needs, requirements, and preferences of people with cognitive disabilities are diverse. This ought to be reflected in accessibility guidelines and standards. Studies to systematically develop and recommend effective accessibility measures are needed to address current knowledge gaps.

  • 126. Borgström, Henrik
    et al.
    Harlin, Peter
    Dalarna University, School of Technology and Business Studies, Material Science.
    Olsson, Mikael
    Dalarna University, School of Technology and Business Studies, Material Science.
    Paiar, Tomaso
    Wang, Yu
    Nyborg, Lars
    Possibilities and constraints of implementing starch consolidated high speed steel in prototyping2008In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 475, no 1-2, p. 34-38Article in journal (Refereed)
    Abstract [en]

    In the starch consolidation (SC) process, a water-based slurry containing powder, starch, dispersant and thickener is used to fabricate near net-shape green bodies that are de-binded and further consolidated by sintering. In this study, gas atomized M3/2 as well as high and low carbon V-rich M4 type high speed steel powder (<150 mu m) are considered, Both material types undergo high volumetric shrinkage during super-solidus liquid phase sintering enabling them to reach near full density. The analyses and the review cover different process aspects like: recipe optimisation, post-gelatinization drying, de-binding and sintering. A SC recipe consisting of 58 vol.% powder, 3 vol.% starch, 1 vol.% dispersant and a thickener solution resulted in a density of >98% than what is theoretically stated after sintering. It is found that the success of the post-gelatinization drying procedure depends on the smoothness of mould material and controlling powder oxidation. The best combination was freeze drying the slurry in a silicon rubber mould. For V-rich alloys a total or partial control of eutectic carbides in the final microstructure could be realized for vacuum and nitrogen sintering atmospheres, respectively.

  • 127.
    Bouvier, Jean-Louis
    Dalarna University, School of Technology and Business Studies, Environmental Engineering.
    Evaluation of the impact of the PV electrification of islands on the Titicaca Lake and its reproducibility2005Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Lots of countries are now running projects in order to increase their electrification rate. One of the means used to achieve this goal is the Solar Home System, SHS. It is with this intention that a project was born in Peru. The concept was to sell a SHS which includes roughly a PV panel, a battery, one regulator and lamps with the help of a loan. This project has been carried out from 1996 to 1999 with the installation of 421 SHS. An evaluation is now necessary for the authorities to realize on the finality of those kinds of PV projects and more merely to prevent the same errors in the following SHS. This evaluation has taken into account the standard technical and economical points of view but also the social and environmental effects of those installations. It has been achieved by observations and by a survey performed in 49 families. Moreover the investigation has also lead me to meet different actors like school teacher, mayor etc. Although the social results is ambivalent (there are good and bad aspects of the electrification of a community), economically and environmentally it is success.

  • 128.
    Brandsma, Age
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Performance Evaluation for a Solar Assisted Air Conditioning System in Taipei2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report shows the study performed at Taipei National University of Technology in Taipei to evaluate the performance of a solar air conditioning system. The performance is evaluated under Taiwan climate conditions. The research is performed under summer weather conditions. No influence is done on these conditions. A solar air conditioning system currently available on the market is used. No changes are made to the system.

    The work to be done is divided into different phases in order to guide the process. First, a literature research is done to find similar research done on this topic and to gain a basic understanding of the topic. Then several measurement plans are made to investigate different parts of the system.. Measurements are done. It is tried to developing a computer model in order to be able to simulate the system performance.

    The overall objective was to gain knowledge about a solar assisted air-conditioning system and develop a model to simulate the system. Initially a list of research questions was made in order to quantify ‘gaining knowledge’ about the system. The plan was to answer them by using measurement data and creating a model to perform simulations. There are measurements done in this report, however due to too many ‘unknowns’* it is difficult to draw conclusions from them. A lot of research questions are still open and they are also not included in this report. It is also not succeeded to make a working model of a solar assisted air conditioner.

    It is succeeded in making a model to predict the performance of the evaporator. This model is currently within 11% accurate.

  • 129.
    Brinkebäck, Eric
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Jönsson, Johan
    Dalarna University, School of Technology and Business Studies, Construction.
    Fallstudie av moderna timmerhus: Kvalitetskontroll av nybyggda timmerhus mot FST:s kvalitetsnormer och BBR:s kommande energihushållningskrav2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A study has been conducted to investigate how log houses will meet the new requirements regarding U-value and specific energy use with primary energy factor as a basis, which will be put into use in 2017. In the study, two houses have been investigated. Both houses were constructed with 200 mm thick logs without any additional isolation. Both houses have geothermal heating systems. The study found that the new requirements will be rough against timber house constructions with geothermal or electricity as a heating system, since a primary energy figure of 1.6 will be multiplied by the total energy consumption when heated by electricity.

  • 130. Broman, Lars
    et al.
    Nordlander, Svante
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Solar cornets for concentration of sunlight onto solar cells1987Report (Other academic)
  • 131.
    Brosius, Isabelle
    Dalarna University, School of Technology and Business Studies, Construction.
    Utfackningsväggar i trä: En tid- och kostnadsjämförelse mellan prefabricerade och platsbyggda byggmetoder2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To win procurements today, it is important that you as an entrepreneur choose the most effective resource and production methods. That already in the calculation stage, decide how high degree of prefabrication the project should have, is favorable to promptly adapt the workplace in order to get the best output.

    In Mora, Skanska has a block workshop that among other things manufactures curtain walls. Skanska has expressed a desire for a study of the differences in time and cost between their precast curtain walls and site-built curtain walls in order to see for which construction projects it may be appropriate to make use of their precast curtain walls.

    The purpose of this project is to facilitate the choice of production method for the manufacture of curtain walls, depending on the construction project's requirements regarding:

    • If the project has a short or long timetable.
    • How many square meters of curtain-wall the project needs.
    • Distance to block workshop.

    The work is defined to include construction projects that have a bearing frame with lightweight curtain walls of wood. The production methods studied for building curtain walls in wood is prefabrication and site-built.

    The production cost has defined to only conclude the cost of the work and the expenses of the workplace, no costs for the materials that are built-in are included. The cost of the built-in materials is assumed in this work to be the same whether the curtain walls are site built or prefabricated.

    With unit times from the block workshop, has a production time for prefabrication of curtain walls been calculated. For the site-built curtain wall, unit times from Nybyggnadslistan 1999 has been retrieved and used to calculate a manufacturing time for building the wall in place. A cost benefit analysis has been done comparing the different manufacturing cost. The cost benefit analysis show the amount of wall area required to choose prefabricated over place built at the highest profit.

    The result shows that to manufacture and mount one square meter of prefabricated curtain wall takes 0,135 hours less time than that place build the same amount. Time on site is reduced by 0,578 hours per square meter when using precast curtain walls.

    The result also shows that the cost to manufacture one square meter of curtain-wall is 32.77 SEK lower than that place build the same amount of curtain-wall. The thing that pulls up the cost of precast curtain walls is the transport. A fully loaded truck with 370 m² of wall can be transported 43 Swedish miles before profitability ceiling is reached.

    The time at the construction place, is getting shorter when using prefabricated curtain walls, leading to reduced costs in the workplace.

    For a construction project located at a distance of 30 Swedish miles from block workshop, is it profitable to choose prefabricated curtain walls, if the object needs 256 m² or more square meters of wall. For construction projects that require a smaller number of square meters of curtain walls, it is more profitable to use the site-built curtain walls. Especially if the construction project is located at a far distance from the block workshop.

    Important conclusions from this thesis are:

    • Shorter production time for precast curtain walls, which results in a lower production cost.
    • The time on the construction site is reduced by the use of precast curtain walls.
    • For long trips, a larger number of square meters precast curtain walls is needed to make the use of prefab to be profitable.
    • The use of precast curtain walls means less need for storage of materials on the construction site.
  • 132.
    Brunnert Walfridsson, Erik
    Dalarna University.
    NGL2014 Next Generation Learning Conference: Conference summary2014Conference proceedings (editor) (Other academic)
  • 133.
    Budny, Rasmus
    Dalarna University, School of Humanities and Media Studies, Sound and Music Production.
    Kunskap för kreativitet: En undersökning av kreativitet i teori och praktik2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Den här studien undersöker teoretiska definitioner av kreativitet, förhållandet mellan kreativitet och kunskap, och låtskrivares strategier för att uppnå kreativitet. Låtskrivande är den skapandeprocess som ska resultera i en färdig musikprodukt. Kreativitet innebär brytande av gamla regler och konventioner för att skapa någonting nytt. Varje musikgenre har specifika regler och konventioner för hur den ska låta och uppfattas, vilket då innebär att man måste ha kunskap om dem för att kunna skriva musik inom den valda genren. Detta kan få låtskrivarprocessen att förefalla som ickekreativ, trots att låtskrivande är känt som en konstnärlig och kreativ uttrycksform. I den här studien användes kvalitativa intervjuer för att ge svar på forskningsfrågorna. Tre erfarna och tre mindre erfarna låtskrivare intervjuades, vilka berättade om sina musikkunskaper, definitioner av kreativitet och skapandeprocesser. Resultaten visade att låtskrivarna inte uppfattade att deras musikkunskap var hämmande för deras kreativitet. Studien visade att låtskrivarna hade utvecklat specifika strategier för hur de skulle kunna skapa på rutin och få tillgång till sin kreativitet. Slutligen definierade låtskrivarna specifika faktorer som påverkade kreativiteten, som till exempel psykiska och fysiska distraktioner.  

  • 134.
    Burlin, Toivo
    Dalarna University, School of Languages and Media Studies, Sound and Music Production.
    Tukkipoika: Some Comments on recordings of North Swedish Folk Music2013In: Nordisk forskarkonferens inom Ljud- och musikproduktion Falun 13-14 november 2013: Conference proceedings / [ed] Berk Sirman, Falun, 2013, p. 8-8Conference paper (Refereed)
  • 135.
    Butt, Abdul Haleem
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Speech Assessment for the Classification of Hypokinetic Dysthria in Parkinson Disease2012Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of this thesis is to investigate computerized voice assessment methods to classify between the normal and Dysarthric speech signals. In this proposed system, computerized assessment methods equipped with signal processing and artificial intelligence techniques have been introduced. The sentences used for the measurement of inter-stress intervals (ISI) were read by each subject. These sentences were computed for comparisons between normal and impaired voice. Band pass filter has been used for the preprocessing of speech samples. Speech segmentation is performed using signal energy and spectral centroid to separate voiced and unvoiced areas in speech signal. Acoustic features are extracted from the LPC model and speech segments from each audio signal to find the anomalies. The speech features which have been assessed for classification are Energy Entropy, Zero crossing rate (ZCR), Spectral-Centroid, Mean Fundamental-Frequency (Meanf0), Jitter (RAP), Jitter (PPQ), and Shimmer (APQ). Naïve Bayes (NB) has been used for speech classification. For speech test-1 and test-2, 72% and 80% accuracies of classification between healthy and impaired speech samples have been achieved respectively using the NB. For speech test-3, 64% correct classification is achieved using the NB. The results direct the possibility of speech impairment classification in PD patients based on the clinical rating scale.

  • 136.
    Byström, Kurt
    Dalarna University, Not School affiliated.
    From a traditional academic library to a modern learning environment: Dalarna University Library - expectations and results2016Report (Other (popular science, discussion, etc.))
    Abstract [en]

    This report describes the ideas and vision behind Dalarna University's award-winning library in Falun. A description of the planning and construction processes and an evaluation of the final outcome are presented together with experiences and observations drawn from the project.

  • 137.
    Byström, Kurt
    Dalarna University, Not School affiliated.
    Från traditionellt akademiskt bibliotek till modern lärmiljö: Högskolan Dalarnas bibliotek – förväntningar och resultat2016Report (Other (popular science, discussion, etc.))
    Abstract [sv]

    I denna rapport beskrivs idéerna bakom Högskolan Dalarnas prisbelönta bibliotek i Falun. Planerings- och byggprocessen beskrivs och det färdiga resultatet utvärderas, samt de erfarenheter som har gjorts delas.

  • 138.
    Bäck, Malin
    et al.
    Dalarna University, School of Technology and Business Studies, Graphic Arts Technology.
    Wennemyr, Elin
    Dalarna University, School of Technology and Business Studies, Graphic Arts Technology.
    Digital anpassning av nyhetsbrev för portabla digitala enheter2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    Today we have become increasingly dependent of our digital portable

    devices and constantly bring these with us. So, it goes without saying,

    we should adapt newsletters to this reality and not let the design be based

    on more traditional, stationary devices. The adaptation of how a interface

    should work is controlled by which audience you are targeting. In this

    project, we have worked with Sveriges MotorCyklisters members as target

    group.

    This target group consists of men to the larger part and at a age of 41-65

    years. Through a combination of a qualitative and a quantitative survey

    we have been able to create examples of guidelines for functionality and

    overview, directed towards the target group. The results show that they

    prefer a simple design that is easy to navigate and do not consist of too

    much irrelevant information and that easily leads on from headlines to

    articles. It is important to the group that there are clear, distinct and large

    buttons and texts which are customizable with a high degree of readability,

    regardless of which device the material presented on. All of these

    data were collected from surveys and interviews with members of SMC.

  • 139.
    Bäcke, Linda
    Dalarna University, School of Technology and Business Studies, Material Science.
    Modeling the effect of solute drag on recovery and recrystallization during hot deformation of Nb microalloyed steels2010In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 50, no 2, p. 239-247Article in journal (Refereed)
    Abstract [en]

    The effect of solute drag on recovery and recrystallization during hot deformation of Nb microalloyed steels has been modeled using a newly developed microstructure model. The model is based on dislocation theory and the calculated dislocation density determines the driving force for recrystallization. Subgrains act as nuclei for recrystallization and have to reach a critical size and configuration in order for recrystallization to start. In the model, the solute drag effect of Nb in solution is described. Nb retards both dislocation and grain boundary movement giving retardation in both recovery and recrystallization. Calculations were compared to experimental results from axisymmetric compression tests combined with stress relaxation. In order to model the effect of solute drag, the experiments were carried out at temperatures where precipitation of Nb(C, N) should not occur. The calculated flow stresses for the compression tests show good fit with experimental data. Also, the calculated results of the relaxation tests show good agreement with experimental data.

  • 140.
    Böe, Hampus
    Dalarna University, School of Technology and Business Studies, Materials Technology.
    Härdprocessens inverkan på sprickuppkomst och spricktillväxt vid induktionshärdning av Ovako 495B: Seghärdning i induktionsline2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract Induction hardening is a rapid thermal hardening process with high demands on the equipment. Ovako Sweden AB in Hällefors performs induction hardening on steel grade 495B and has major problems with crack initiation and propagation. The purpose of this work is to investigate how induction hardening affects the crack initiation and crack growth in the material and find the factors with major influences. It is very important to meet the customer's demands on hardness profile through the whole cross section. Two different tests have been performed where the goal has been to find an operational process that minimizes crack initiation and crack growth. The results of test one showing that the hardening temperature can be reduced from 915 ˚C down to 870 ˚C. Test two shows that cracks can be minimized if the cooling is done with a polymeric coolant instead of pure water and also achieve a more equal hardness profile. Based on the presented results more tests can be carried out to verify a new way of operational process that leads to a heavily reduced risk for cracks in the material. The two most critical bar diameters have been examined with focus upon the hardening temperature and cooling rate.

  • 141.
    Cai, Cai
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    An application of gravity p-median model with different distance decay functions2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The location-allocation problem has been studied over 50 years and recently a

    new method called “gravity p-median model” is introduced to the public. The key

    idea is that the probability of customers visit a facility is based on a distance decay

    function rather than directly choose the nearest one. An empirical test shows that the

    solution of gravity p-median model with exponential distance decay function is

    unstable and of limit use.

    This paper extends the research to apply gravity p-median model with three

    different distance decay functions in Dalecarlia, Sweden. The distance decay

    functions are estimated from a Swedish survey by maximum likelihood estimation.

    The models are optimized by simulated annealing. The result suggests that different

    distance decay functions dominate the solutions of gravity p-median model, and the

    log-normal decay function can provide stable solutions.

  • 142.
    Campanyim, Sunitda
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Laine, Jenny
    Dalarna University, School of Technology and Business Studies, Construction.
    Samband mellan vägytans textur och buller i vägfordon2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today, there are several authorities in Sweden that have responsibilities toregulate noise emission levels to limits that are not too disruptive to theenvironment. Currently there are no guidelines or recommendations for interiornoise in vehicles. Since there are no clear requirements for noise levels invehicles, there is also no standard method to measure noise inside the vehicle.The aim of this thesis was to develop correlations between the road surfacetexture and noise levels in vehicles and suggest appropriate research methodswhen studying how noise generated in the contact area between tire and roadsurface affects the inside of the vehicle.

    The study was divided into two phases: a measurement of road texture ondifferent coating types and a noise examination with different vehicles atselected test sections.

    The study showed that the methods used did not work properly and gaveunreliable results. Road surface texture has to some degree influence on thenoise generated by the traffic but to find a good correlation between the roadsurface texture and noise inside vehicles, other sources of error have to beminimized.To develop a reliable method more investigations are needed.

  • 143.
    Candell, André
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Ehn Jansson, Oskar
    Dalarna University, School of Technology and Business Studies, Construction.
    Synsättet på förnyelsebara elkällor inom fastighetsbranschen2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Between the years 1965 and 1975 one million residences in Sweden were built.

    Today the work of renovating these buildings has begun, in connection with this

    work there are many measures taken to reduce energy usage.

    The purpose of this work was to find out what is the most economical choice of

    various green power sources.

    Also the thoughts and beliefs of the property owners are set in relation to the

    conclusions of the calculations to get an idea of how different the property

    owner’s beliefs are compared to the calculations.

    To avoid making the work too large and demanding these boundaries have been

    set:

     To get appropriate conclusions the work has been limited to the region

    of Dalarna.

     The work has also been limited to examining the economic factor when

    choosing between various green power sources.

    Two surveys were conducted with several different property owners as

    participants and then two calculations of the payback period for solar power,

    wind power, and green electricity were conducted. These two results were then

    compered to each other to be able to analyze and present these conclusions.

    Conclusions:

     Wind power is not profitable at today’s electricity prices.

     Real estate owners are uncertain of what choice gives the best

    profitability of wind power, solar power or green power.

  • 144.
    Cano Garcia, Jose
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Damp Heat Degradation of CIGS Solar Modules2017Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Due to the short period that some photovoltaic technologies have taken part on the solar energy market, it is crucial to evaluate the long term stability of solar cells belonging to those technologies in order to ensure a minimum lifetime of their performance. Accelerated degradation tests are thus carried out to achieve such goals.

    The present study analyzes the encapsulation effects on co-evaporated manufactured Copper Indium Gallium Selenide (CIGS) solar cells under damp heat conditions, consisting in 85 °C and 85 % relative humidity, during an approximated period of 1000 hours. The experimental procedure has been carried out at Solliance Solar Research facilities.

    Since the encapsulation packages play a critical role as a protection to achieve long term stability of the solar cells and modules, several packaging structures and materials has been taken into study. Thus, eighteen types of mini modules were manufactured including different combinations of encapsulants, front sheet foils, thin film protective barriers and CIGS cells from different manufacturers. The design of these mini modules and the manufacturing process to obtain them is also presented in this work. Various characterization techniques were carried out in order to acquire the required information about the solar cells and encapsulants performance along the damp heat degradation process.

    The results exposed that encapsulation packages including thin film barriers between the encapsulant and the front sheet foil allowed a longer solar cell lifetime due to their remarkable protection against moisture ingress. Moreover, the degradation of the molybdenum layer included in the CIGS cells was found as principal cause of efficiency decrement and end of performance of solar cells protected by regular encapsulant and front sheet foils. Some other findings in relation with the evaluated components are shown along the present study.

  • 145. Canovic, Sead
    et al.
    Engkvist, Josefin
    Dalarna University, School of Technology and Business Studies, Material Science.
    Liu, Fang
    Götlind, Helena
    Hellström, Kristina
    Svensson, Jan-Erik
    Johansson, Lars-Gunnar
    Olsson, Mikael
    Dalarna University, School of Technology and Business Studies, Material Science.
    Halvarsson, Mats
    Microstructural investigation of the initial oxidation of the FeCrAlRE alloy Kanthal AF in dry and wet O2 at 600 and 800°C2010In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 157, no 6, p. C223-C230Article in journal (Refereed)
    Abstract [en]

    The FeCrAlRE (where RE is reactive element) alloy Kanthal AF was exposed isothermally at 600 and 800°C for 72 h in dry O2 and in O2 with 10 vol % H2O. The mass gains were 3–5 times higher at the higher temperature. The presence of water vapor increased the oxidation rate at 800°C, while no significant effect was observed at 600°C. A thin two-layered oxide formed at 600°C: an outer (Fe,Cr)2O3 corundum-type oxide, containing some Al, and an inner, probably amorphous, Al-rich oxide. At 800°C a two-layered oxide formed in both environments. The inner layer consisted of inward grown a-Al2O3. In dry O2 the originally formed outward grown g-Al2O3 had transformed to a-Al2O3 after 72 h. Water vapor stabilized the outward grown g-Al2O3 and hence no transformation occurred after 72 h in humid environment. RE-rich oxide particles with varying composition (Y, Zr, and Ti) were distributed in the base oxide at both temperatures and in both environments. The RE-rich particles were separated from the alloy substrate by a layer of Al-rich oxide. At 800°C the Y-rich RE particles were surrounded by thick oxide patches in both dry and humid O2.

  • 146. Cantos-Soto, María Elena
    et al.
    Fernández-García, Aránzazu
    Matteudi, Maud
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Martínez-Arcos, Lucía
    Solar Reflectors Degradation Caused by Simulated Solar Radiation2012In: Solar PACES 2012, 2012Conference paper (Other academic)
    Abstract [en]

    The feasibility of concentrating solar power (CSP) technologies strongly depends on the material used toachieve a suitable solar reflector. A very relevant issue nowadays is to find a cost-effective reflector materialwith appropriate optical properties, able to resist the environmental stress and, therefore, extending itslifetime. This research work is focused on evaluating the thick silvered-glass reflector’s degradation causedby solar radiation onto different solar reflector samples, exposed to both experimental settings, simulatedsunlight under accelerated conditions and solar radiation at real outdoor conditions. The experiments havebeen performed in the optical characterization and durability of solar reflectors laboratory at the PlataformaSolar de Almeria (PSA). Three different chambers were used to reproduce the entire or specifics ranges ofthe solar radiation spectrum. Samples from 6 different manufacturers were placed inside of every sunlightchamber during 2000 hours. The outdoor exposure in the PSA precincts lasted for 4000 hours.

  • 147. Cao, x
    et al.
    Yuan, Y
    Xiang, B
    Sun, L
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Numerical investigation on optimal number of longitudinal fins in horizontal annular phase change unit at different wall temperatures2018In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 158, p. 384-392Article in journal (Refereed)
  • 148.
    Carling, Kenneth
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Han, Mengjie
    Dalarna University, School of Technology and Business Studies, Statistics.
    Håkansson, Johan
    Dalarna University, School of Technology and Business Studies, Information Systems.
    Rebreyend, Pascal
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Distance measure and the p-median problem in rural areas2015In: Annals of Operations Research, ISSN 0254-5330, E-ISSN 1572-9338, Vol. 226, no 1, p. 89-99Article in journal (Refereed)
    Abstract [en]

    The p-median model is used to locate P facilities to serve a geographically distributed population. Conventionally, it is assumed that the population patronize the nearest facility and that the distance between the resident and the facility may be measured by the Euclidean distance. Carling, Han, and Håkansson (2012) compared two network distances with the Euclidean in a rural region with a sparse, heterogeneous network and a non-symmetric distribution of the population. For a coarse network and P small, they found, in contrast to the literature, the Euclidean distance to be problematic. In this paper we extend their work by use of a refined network and study systematically the case when P is of varying size (1-100 facilities). We find that the network distance give as good a solution as the travel-time network. The Euclidean distance gives solutions some 4-10 per cent worse than the network distances, and the solutions tend to deteriorate with increasing P. Our conclusions extend to intra-urban location problems.

  • 149.
    Carling, Kenneth
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Håkansson, Johan
    Dalarna University, School of Technology and Business Studies, Human Geography.
    A compelling argument for the gravity p-median model2013In: European Journal of Operational Research, ISSN 0377-2217, E-ISSN 1872-6860, Vol. 226, no 3, p. 658-660Article in journal (Refereed)
    Abstract [en]

    The p-median model is used to locate P facilities to serve a geographically distributed population. Conventionally, it is assumed that the population always travels to the nearest facility. Drezner and Drezner (2006, 2007) provide three arguments on why this assumption might be incorrect, and they introduce the extended gravity p-median model to relax the assumption. We favour the gravity p-median model, but we note that in an applied setting, the three arguments are incomplete. In this communication, we point at the existence of a fourth compelling argument for the gravity p-median model.

  • 150.
    Carling, Kenneth
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    Håkansson, Johan
    Dalarna University, School of Technology and Business Studies, Human Geography.
    Jia, Tao
    School of Remote Sensing and Information Engineering, Wuhan University.
    Out-of-town shopping and its induced CO2-emissions2013Report (Other academic)
    Abstract [en]

    Planning policies in several European countries have aimed at hindering the expansion of out-of-town shopping centers. One argument for this is concern for the increase in transport and a resulting increase in environmental externalities such as CO2-emissions. This concern is weakly founded in science as few studies have attempted to measure CO2-emissions of shopping trips as a function of the location of the shopping centers. In this paper we conduct a counter-factual analysis comparing downtown, edge-of-town and out-of-town shopping. In this comparison we use GPS to track 250 consumers over a time-span of two months in a Swedish region. The GPS-data enters the Oguchi’s formula to obtain shopping trip-specific CO2-emissions. We find that consumers’ out-of-town shopping would generate an excess of 60 per cent CO2-emissions whereas downtown and edge-of-town shopping centers are comparable.

1234567 101 - 150 of 1341
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • chicago-author-date
  • chicago-note-bibliography
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf