du.sePublications
Change search
Refine search result
1234567 1 - 50 of 1247
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.
  • 1.
    Abd Alrahman, Chadi
    Dalarna University, School of Technology and Business Studies, Electrical Engineering.
    Evaluation of a PVT Air Collector2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Hybrid Photovoltaic Thermal (PVT) collectors are an emerging technology that

    combines PV and solar thermal systems in a single solar collector producing heat and

    electricity simultaneously. The focus of this thesis work is to evaluate the performance of

    unglazed open loop PVT air system integrated on a garage roof in Borlänge. As it is

    thought to have a significant potential for preheating ventilation of the building and

    improving the PV modules electrical efficiency. The performance evaluation is important

    to optimize the cooling strategy of the collector in order to enhance its electrical efficiency

    and maximize the production of thermal energy. The evaluation process involves

    monitoring the electrical and thermal energies for a certain period of time and investigating

    the cooling effect on the performance through controlling the air mass flow provided by a

    variable speed fan connected to the collector by an air distribution duct. The distribution

    duct transfers the heated outlet air from the collector to inside the building.

    The PVT air collector consists of 34 Solibro CIGS type PV modules (115 Wp for each

    module) which are roof integrated and have replaced the traditional roof material. The

    collector is oriented toward the south-west with a tilt of 29 ᵒ. The collector consists of 17

    parallel air ducts formed between the PV modules and the insulated roof surface. Each air

    duct has a depth of 0.05 m, length of 2.38 m and width of 2.38 m. The air ducts are

    connected to each other through holes. The monitoring system is based on using T-type

    thermocouples to measure the relevant temperatures, air sensor to measure the air mass

    flow. These parameters are needed to calculate the thermal energy. The monitoring system

    contains also voltage dividers to measure the PV modules voltage and shunt resistance to

    measure the PV current, and AC energy meters which are needed to calculate the

    produced electrical energy. All signals recorded from the thermocouples, voltage dividers

    and shunt resistances are connected to data loggers. The strategy of cooling in this work

    was based on switching the fan on, only when the difference between the air duct

    temperature (under the middle of top of PV column) and the room temperature becomes

    higher than 5 °C. This strategy was effective in term of avoiding high electrical

    consumption by the fan, and it is recommended for further development. The temperature

    difference of 5 °C is the minimum value to compensate the heat losses in the collecting

    duct and distribution duct.

    The PVT air collector has an area of (Ac=32 m2), and air mass flow of 0.002 kg/s m2.

    The nominal output power of the collector is 4 kWppv (34 CIGS modules with 115

    Wppvfor each module). The collector produces thermal output energy of 6.88 kWth/day

    (0.21 kWth/m2 day) and an electrical output energy of 13.46 kWhel/day (0.42 kWhel/m2

    day) with cooling case. The PVT air collector has a daily thermal energy yield of 1.72

    kWhth/kWppv, and a daily PV electrical energy yield of 3.36 kWhel /kWppv. The fan energy

    requirement in this case was 0.18 kWh/day which is very small compared to the electrical

    energy generated by the PV collector. The obtained thermal efficiency was 8 % which is

    small compared to the results reported in literature for PVT air collectors. The small

    thermal efficiency was due to small operating air mass flow. Therefore, the study suggests

    increasing the air mass flow by a factor of 25. The electrical efficiency was fluctuating

    around 14 %, which is higher than the theoretical efficiency of the PV modules, and this

    discrepancy was due to the poor method of recording the solar irradiance in the location.

    Due to shading effect, it was better to use more than one pyranometer.

  • 2.
    Abdel Rahman, Assem
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Electrical Evaluation of a Low Concentrating PVT Collector Based on Performance Ratio2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Photovoltaic Thermal/Hybrid collectors are an emerging technology that combines PV

    and solar thermal collectors by producing heat and electricity simultaneously. In this paper,

    the electrical performance evaluation of a low concentrating PVT collector was done

    through two testing parts: power comparison and performance ratio testing. For the

    performance ratio testing, it is required to identify and measure the factors affecting the

    performance ratio on a low concentrating PVT collector. Factors such as PV cell

    configuration, collector acceptance angle, flow rate, tracking the sun, temperature

    dependence and diffuse to irradiance ratio.

    Solarus low concentrating PVT collector V12 was tested at Dalarna University in Sweden

    using the electrical equipment at the solar laboratory. The PV testing has showed

    differences between the two receivers. Back2 was producing 1.8 energy output more than

    Back1 throughout the day. Front1 and Front2 were almost the same output performance.

    Performance tests showed that the cell configuration for Receiver2 with cells grouping (6-

    32-32-6) has proved to have a better performance ratio when to it comes to minimizing

    the shading effect leading to more output power throughout the day because of lowering

    the mismatch losses. Different factors were measured and presented in this thesis in

    chapter 5.

    With the current design, it has been obtained a peak power at STC of 107W per receiver.

    The solar cells have an electrical efficiency of approximately 19% while the maximum

    measured electrical efficiency for the collector was approximately 18 % per active cell area,

    in addition to a temperature coefficient of -0.53%/ ˚C. Finally a recommendation was

    done to help Solarus AB to know how much the electrical performance is affected during

    variable ambient condition and be able to use the results for analyzing and introducing

    new modification if needed.

  • 3.
    Abdi, Faisa
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Farah, Muse
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Energieffektivisering av Limatvätten AB: Värmeåtervinning från manglar2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Energy efficiency is in the interest of all industries, as it involves the reduction of both energy and cost. The purpose of this project for a bachelor’s degree is to analyse potential energy recovery of waste heat from an ironer.

    The work was carried out at Limatvätten AB, which is a large and modern laundry facility. Limatvätten AB is a textile service company that has been in existence for 50 years. The Lima laundry’s main customers are from the hotel and restaurant business. Limatvätten AB has its own textiles that are rented to hotels, conferences, etc. The largest customers are in Sälenfjällen and in the Siljan region.

    The work is done by identifying moisture, temperature and dynamic pressure in an ironer Based on measurements, the amount of energy that can be recycled is calculated. Heat recovery system proposals are also given in the report. Aquavent is a heat exchanger that uses ventilation heat from the ironers. The water that is heated in the aquavent is led into the washing pipes, which leads to the reduction of steam consumption in washing processes. Temperature change depends on the heat exchanger's efficiency, the higher the temperature change, the more amount of energy recovery is obtained.

    After identification of the problem, a timetable was mapped, and appropriate instruments and interesting parameters were chosen. The moisture content, temperature and dynamic pressure have been measured. The equations described in the theory section are used for most of the calculations with the help of Excel.

    According to the result, the energy saving will be 184 MWh/year if all excess heat from a mangle is reused. Based on the result, the total savings potential is SEK 57 000 /year. According to the results, it is shown that there is the potential to use excess heat from the Lima wash ironers. In addition to the saving of energy, climate impact is also reduced, as the excess energy is again reused which would otherwise disappear into the atmosphere. If two of the ironers are coupled with a heat recovery system, it results in a doubling on the savings potential.

  • 4.
    Abdi Mohammed, Farhan
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    A Said, Mahdi
    Dalarna University, School of Technology and Business Studies, Construction.
    Möjligheten att utföra LCA i en totalentreprenad: En studie om LCA i en totalentreprenad2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The environment is an important issue in society today. Emissions contribute to medium temperature rises gradually allowing the consequences on the nature, climate and society. The construction industry accounts for approximately 40 % of all energy use in Sweden. The environment in various ways, namely that different lifestyles and ways of life such as heating residences, waste management, travel to and from work affects the adverse impact on the environment. With the help of the growing awareness of the environment and the impetus given to it by the public authorities to reduces the environmental impact and energy use. LCA is a systematic analysis that is new in the construction industry where construction processes measured by the flow of energy and material usage. LCA can help decision makers by performing the LCA can be developed in analytical evaluations environmentally. Without LCA would investment, costs may be the most important thing for the decision makers than the environmental benefits. The aim of this work is to perform a life cycle assessment in the construction process with total construction and following questions is: • Possibilities to perform LCA in this construction form? • What demands are made from the client? • Possibilities and difficulties with total construction to perform LCA? The aim of this thesis is to illustrate how a life cycle analysis can be performed in a total construction. The study will highlight the role of the client. The focus will be on project Kungsljuset in Borlänge. The method of accounting analysis of the life cycle of the construction project is used and performed in a total construction. Interviews with the project management for this object. The result was unfortunately that there was a lack of data for the implement of LCA in this project. The reason was the knowledge and interest of the lack of both the client and the material supplier. It is required that the client demands on the material supplier and entrepreneur to specify the material and other resources used in this construction project.

  • 5.
    Abrahamsson, Jonas
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Lindqvist, Jakob
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Nedsmutsade värmesystems påverkan på energisystemet: Effektivisering vid användning av rengöringsmetoder2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Contamination of the heating system is not a well-known problem that can have major economic consequences. Due to minerals and low pH in the system arises limescale and corrosion that can clog the system and can damage components. This will result in increased energy consumption for users and a higher energy input from the district heating company. The purpose of this work is to study different cleaning methods for heating systems and if it is viable with cleaning of heating systems. The cleaning effect on the district heating demand and how it affects greenhouse gas emissions and primary energy use. And examine whether the maintenance of the heating system provides less energy than remodeling the building envelope. Previous studies in this area were examined and relevant data were collected after talks with interesting companies working with cleaning of heating systems. Cleaning the heating system was compared with various packages such as remodeling of the building envelope and heat recovery ventilation. Cleaning the heating systems with an efficiency of 10 % resulting in a reduced heating need at 1,63 GWh per year and a reduction in emissions of 177 tonnes CO2e per year. The reduced heating demand resulted in a reduction in primary energy consumption by 113 750 kWh per year. Installation of the cleaning systems can result in a saving for Tunabyggen of 759 200 SEK per year. The conclusion of this work is that the cleaning prolongs the lifetime of heating systems, but can’t replace remodeling of the building envelope in terms of reduced energy consumption.

  • 6.
    Abramowska, Magdalena
    et al.
    Dalarna University, School of Technology and Business Studies, Graphic Arts Technology.
    Ehnlund, Isabell
    Dalarna University, School of Technology and Business Studies, Graphic Arts Technology.
    Snowboardens bildspråk 1980-2010: En kartläggning2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Snowboarding is today a major winter sport with its own equipment, its own culture and elite riders. For professional athletes or for those who just snowboard for fun, snowboard becomes an extension of their body while in motion.

    The layout on the boards has changed over the years but despite of this there is a lack of scientific studies in the field. Therefore, this study aimed to identify how the graphics of 240 snowboards have evolved between 1980-2010, and fill some of these holes in the scientific documentation. 

    This survey was based on a visual content analysis, which resulted in interesting observations. The results that emerged were that the result can be generalized and that the development of snowboards graphics has changed over the decades. Snowboards from the various decades have specific characteristics that this study provides.

  • 7.
    Abreu Saraiva Freitas, Iuri
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Indoor climate: A comparison of residential units in Tjärna Ängar, Borlänge before and after retrofitting2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study try to understand which aspects were fundamental to indoor climate and how to obtain them in order to provide the best possible experience in the thermal comfort of individuals. Thus, arose the studies of Fanger, which was the seed for a new era of discoveries in the area and founded the knowledge our society have today in this globally used standards and norms. Referring to these fundamental aspects of the indoor comfort, data collection was taken in situ to show in details what was happening. This study was executed in order to demonstrate the differences between the data previous and after a process of retrofitting in dwellings built in the 60s and 70s of the century past, in the district of Tjärna Ängar, Borlänge, Sweden. The comparative results using criteria such as Predicted Mean Vote (PMV), Predicted Percentage Dissatisfied (PPD), Draft Rate (DR), air velocity, Mean Radiant Temperature (MRT), Relative Humidity (RH) and air temperature, showed an improvement in 6 of the 8 parameters analyzed. Confirming the expectation that through the retrofitting the residents will be more satisfied, obtain better quality of indoor climate comfort and also increase occupied area in these dwellings.

  • 8.
    Ackeby, Susanne
    et al.
    STRI AB.
    Tjäder, Jonas
    Bastholm, Caroline
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    The role and interaction of microgrids and centralized grids in developing modern power systems2017Conference paper (Refereed)
    Abstract [en]

    An extension of microgrids is now underway, primarily to allow increased electrification in growing economies but also to meet the need to reduce global CO2 emissions and to provide ancillary services to centralized grids. Energy access constitutes one of the fundamental building blocks for economic growth as well as social equity in the modern world. Access to sustainable energy is needed to achieve sustainable development. A microgrid should not be seen as a competitor to the centralized grid but as a complement.Through examination of several implemented cases from different parts of the world the following topics are considered: Analysis of the interaction between centralized grids and microgrids Analysis of stakeholder decision parameters for electrification Analysis of design differences and requirements for microgrids, depending on the intended purpose and the need of the end customer.It is determined that good planning, suitable requirements and clear regulations for microgrids (in relation to centralized grids) limits the risk of stranded assets and enables better business cases for the involved stakeholders.The paper is based on the discussion paper The role and interaction of microgrids and centralized grids in developing modern power systems – A case review publiced by ISGAN (International Smart Grid Action Network) Annex 6: Power T&D Systems.The discussion paper and further information about ISGAN is available at http://www.iea-isgan.org/.

  • 9.
    Ackemo, Sandra
    Dalarna University, School of Technology and Business Studies, Construction.
    Hästanpassade vägar: I Leksands Kommun2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Approximately 13 000 persons get injured every year in Sweden while riding or handling a horse. Due to regulations, a horse is not allowed on to the walk- and cycle path or the sidewalks. Since some places don’t have paths developed for the horse, the equipage is forced out in trafficked roads. The horse is a prey animal, they run first and then they stop to see what the potential threat was. This, in combination with car driver´s general lack of knowledge about horses, could increase the possibility of an accident.The purpose of this project is to evaluate if the equestrian practitioners find it difficult to be in traffic environment with the horse and how commonly practitioners use public roads with the horse. The purpose is also to provide a review of how well the equestrian practitioners are aware of the traffic rules regarding horses in traffic. The main purpose of this thesis is, however, to offer suggestions on how road design should be improved with regard to road safety, security and accessibility for equestrian practitioners.

    The study was carried out with a questionnaire and studying literature. The questionnaire was handed out to 38 members of the riding club of Leksand. The results show that the knowledge of traffic rules could be increased among the ones who answered the questionnaire. They also think that the horse needs to be a part of the community and infrastructure planning and that all road-users need to learn more about horses in traffic, to better understand its behavior. Other proposals are lowered speed limits for motorized traffic at

  • 10.
    Adegoke, Olutayo
    Dalarna University, School of Technology and Business Studies, Material Science.
    Homogenization of Precipitation Hardening Nickel Based Superalloys2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Allvac 718 Plus and Haynes 282 are relatively new precipitation hardening nickel based superalloys with good high temperature mechanical properties. In addition, the weldability of these superalloys enhances easy fabrication. The combination of high temperature capabilities and superior weldability is unmatched by other precipitation hardening superalloys and linked to the amount of the γ’ hardening precipitates in the materials. Hence, it is these properties that make Allvac 718 Plus and Haynes 282 desirable in the manufacture of hot sections of aero engine components.

    Studies show that cast products are less weldable than wrought products. Segregation of elements in the cast results in inhomogeneous composition which consequently diminishes weldability. Segregation during solidification of the cast products results in dendritic microstructure with the segregating elements occupying interdendritic regions. These segregating elements are trapped in secondary phases present alongside γ matrix. Studies show that in Allvac 718Plus, the segregating phase is Laves while in Haynes 282 the segregating phase is not yet fully determined.

    Thus, the present study investigated the effects of homogenization heat treatments in eliminating segregation in cast Allvac 718 Plus and Haynes 282. Paramount to the study was the effect of different homogenization temperatures and dwell time in the removal of the segregating phases. Experimental methods used to both qualify and quantify the segregating phases included SEM, EDX analysis, manual point count and macro Vickers hardness tests.

    Main results show that there is a reduction in the segregating phases in both materials as homogenization proceeds hence a disappearance of the dendritic structure. In Allvac 718 Plus, plate like structures is observed to be closely associated with the Laves phase at low temperatures and dwell times. In addition, Nb is found to be segregating in the interdendritic areas. The expected trend of increase in Laves as a result of the dissolution of the plate like structures at the initial stage of homogenization is only detectable for few cases. In Haynes 282, white and grey phases are clearly distinguished and Mo is observed to be segregating in interdendritic areas.

  • 11.
    Adolfsson, Julia
    Dalarna University, School of Technology and Business Studies, Civil planning and Construction.
    Strukturplan: Ett verktyg för att planera den framtida fysiska strukturen?2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Arbetet handlar om ett planeringsverktyg i samhällsplaneringen som har benämningen strukturplan. Syftet med arbetet är att undersöka strukturplaners innehåll och om det är ett användbart planeringsverktyg till efterföljande planering som ingår i den formella planeringsprocessen enligt plan- och bygglagen. Även att undersöka varför kommuner väljer att göra en strukturplan som anses vara en informell plansort, istället för att använda de verktyg som plan- och bygglagen erbjuder. Samt undersöka om tidigare forskning stämmer att kommuner använder strukturplaner för att undvika plan- och bygglagsprocessen.

    Arbetets forskningsdesign är fallstudie med en komparativ analys, fallen som valt är; Utvecklad strukturplan för Nacka stad, Strukturplan Storvreten, Strukturplan Forsåker, samt Strukturplan för Lina.

    Metoderna som använts i arbetet är kvalitativ innehållsanalys och semistrukturerade intervjuer.

    Resultatet av innehållsanalysen visar att en strukturplan är ett dokument som på ett övergripande sätt visar den tänkta fysiska grovstrukturen för ett visst geografiskt område i kommunen inom några år. Strukturplanen innehåller kartor, text och bilder som främst visar framtida markanvändningen, befintliga- och framtida bostäder, grönstruktur och trafikstruktur. Den kan även innehålla andra kartor, exempelvis etappindelning och våningsantal, som kommunen tycker är väsentliga att ha med.

    I de semistrukturerade intervjuerna svarade intressenterna att strukturplanen är ett användbart planeringsverktyg till efterföljande planering och används istället för en fördjupning av översiktsplanen för att undvika plan- och bygglagens formella process. Vilket resulterar i att det stämmer överens med den tidigare utredningen En effektivare plan- och byggprocess (SOU 2013:34), ), att kommuner tar fram en strukturplan för att undvika PBL-processen.

    Slutsatsen är att kommuner väljer att göra en strukturplan som lyfter planeringsfrågor och löser planeringsproblem på en övergripande nivå och ska främst användas som ett internt strategisk planeringsverktyg. En strukturplan skapas för att det finns ett högt krav på att publicera bostäder från politikerna och för att den kommunala planeringsprocessen är tidskrävande. Därför väljer kommunen att frångå arbetet med PBL, och gör istället en strukturplan som planeringsverktyg för tidsbesparing och behöver inte genomföra PBLprocessens formella delar.

  • 12.
    Aghanavesi, Somayeh
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Smartphone-based Parkinson’s disease symptom assessment2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis consists of four research papers presenting a microdata analysis approach to assess and evaluate the Parkinson’s disease (PD) motor symptoms using smartphone-based systems. PD is a progressive neurological disorder that is characterized by motor symptoms. It is a complex disease that requires continuous monitoring and multidimensional symptom analysis. Both patients’ perception regarding common symptom and their motor function need to be related to the repeated and time-stamped assessment; with this, the full extent of patient’s condition could be revealed. The smartphone enables and facilitates the remote, long-term and repeated assessment of PD symptoms. Two types of collected data from smartphone were used, one during a three year, and another during one-day clinical study. The data were collected from series of tests consisting of tapping and spiral motor tests. During the second time scale data collection, along smartphone-based measurements patients were video recorded while performing standardized motor tasks according to Unified Parkinson’s disease rating scales (UPDRS).

    At first, the objective of this thesis was to elaborate the state of the art, sensor systems, and measures that were used to detect, assess and quantify the four cardinal and dyskinetic motor symptoms. This was done through a review study. The review showed that smartphones as the new generation of sensing devices are preferred since they are considered as part of patients’ daily accessories, they are available and they include high-resolution activity data. Smartphones can capture important measures such as forces, acceleration and radial displacements that are useful for assessing PD motor symptoms.

    Through the obtained insights from the review study, the second objective of this thesis was to investigate whether a combination of tapping and spiral drawing tests could be useful to quantify dexterity in PD. More specifically, the aim was to develop data-driven methods to quantify and characterize dexterity in PD. The results from this study showed that tapping and spiral drawing tests that were collected by smartphone can detect movements reasonably well related to under- and over-medication.

    The thesis continued by developing an Approximate Entropy (ApEn)-based method, which aimed to measure the amount of temporal irregularity during spiral drawing tests. One of the disabilities associated with PD is the impaired ability to accurately time movements. The increase in timing variability among patients when compared to healthy subjects, suggests that the Basal Ganglia (BG) has a role in interval timing. ApEn method was used to measure temporal irregularity score (TIS) which could significantly differentiate the healthy subjects and patients at different stages of the disease. This method was compared to two other methods which were used to measure the overall drawing impairment and shakiness. TIS had better reliability and responsiveness compared to the other methods. However, in contrast to other methods, the mean scores of the ApEn-based method improved significantly during a 3-year clinical study, indicating a possible impact of pathological BG oscillations in temporal control during spiral drawing tasks. In addition, due to the data collection scheme, the study was limited to have no gold standard for validating the TIS. However, the study continued to further investigate the findings using another screen resolution, new dataset, new patient groups, and for shorter term measurements. The new dataset included the clinical assessments of patients while they performed tests according to UPDRS. The results of this study confirmed the findings in the previous study. Further investigation when assessing the correlation of TIS to clinical ratings showed the amount of temporal irregularity present in the spiral drawing cannot be detected during clinical assessment since TIS is an upper limb high frequency-based measure. 

  • 13.
    Aghanavesi, Somayeh
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Bergquist, Filip
    Nyholm, Dag
    Senek, Marina
    Memedi, Mevludin
    Motion sensor-based assessment of Parkinson’s disease motor symptoms during leg agility tests: results from levodopa challenge2019In: IEEE journal of biomedical and health informatics, ISSN 2168-2194, E-ISSN 2168-2208Article in journal (Refereed)
    Abstract [en]

    Parkinson’s disease (PD) is a degenerative, progressive disorder of the central nervous system that mainly affects motor control. The aim of this study was to develop data-driven methods and test their clinimetric properties to detect and quantify PD motor states using motion sensor data from leg agility tests. Nineteen PD patients were recruited in a levodopa single dose challenge study. PD patients performed leg agility tasks while wearing motion sensors on their lower extremities. Clinical evaluation of video recordings was performed by three movement disorder specialists who used four items from the motor section of the Unified PD Rating Scale (UPDRS), the treatment response scale (TRS) and a dyskinesia score. Using the sensor data, spatiotemporal features were calculated and relevant features were selected by feature selection. Machine learning methods like support vector machines (SVM), decision trees and linear regression, using 10-fold cross validation were trained to predict motor states of the patients. SVM showed the best convergence validity with correlation coefficients of 0.81 to TRS, 0.83 to UPDRS #31 (body bradykinesia and hypokinesia), 0.78 to SUMUPDRS (the sum of the UPDRS items: #26-leg agility, #27-arising from chair and #29-gait), and 0.67 to dyskinesia. Additionally, the SVM-based scores had similar test-retest reliability in relation to clinical ratings. The SVM-based scores were less responsive to treatment effects than the clinical scores, particularly with regards to dyskinesia. In conclusion, the results from this study indicate that using motion sensors during leg agility tests may lead to valid and reliable objective measures of PD motor symptoms.

  • 14.
    Aghanavesi, Somayeh
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Bergquist, Filip
    Gothenburg University.
    Nyholm, Dag
    Uppsala University.
    Senek, Marina
    Uppsala University.
    Memedi, Mevludin
    Örebro University.
    Objective assessment of Parkinson’s disease motor symptoms during leg agility test using motion sensors2018Conference paper (Refereed)
    Abstract [en]

    Title: Objective assessment of Parkinson’s disease motor symptoms during leg agility test using motion sensors

    Objective: To develop and evaluate machine learning methods for assessment of Parkinson’s disease (PD) motor symptoms using leg agility (LA) data collected with motion sensors during a single dose experiment.

    Background: Nineteen advanced PD patients (Gender: 14 males and 5 females, mean age: 71.4, mean years with PD: 9.7, mean years with levodopa: 9.5) were recruited in a single center, open label, single dose clinical trial in Sweden [1].

    Methods: The patients performed up to 15 LA tasks while wearing motions sensors on their foot ankle. They performed tests at pre-defined time points starting from baseline, at the time they received a morning dose (150% of their levodopa equivalent morning dose), and at follow-up time points until the medication wore off. The patients were video recorded while performing the motor tasks. and three movement disorder experts rated the observed motor symptoms using 4 items from the Unified PD Rating Scale (UPDRS) motor section including UPDRS #26 (leg agility), UPDRS #27 (Arising from chair), UPDRS #29 (Gait), UPDRS #31 (Body Bradykinesia and Hypokinesia), and dyskinesia scale. In addition, they rated the overall mobility of the patients using Treatment Response Scale (TRS), ranging from -3 (very off) to 3 (very dyskinetic). Sensors data were processed and their quantitative measures were used to develop machine learning methods, which mapped them to the mean ratings of the three raters. The quality of measurements of the machine learning methods was assessed by convergence validity, test-retest reliability and sensitivity to treatment.

    Results: Results from the 10-fold cross validation showed good convergent validity of the machine learning methods (Support Vector Machines, SVM) with correlation coefficients of 0.81 for TRS, 0.78 for UPDRS #26, 0.69 for UPDRS #27, 0.78 for UPDRS #29, 0.83 for UPDRS #31, and 0.67 for dyskinesia scale (P<0.001). There were good correlations between scores produced by the methods during the first (baseline) and second tests with coefficients ranging from 0.58 to 0.96, indicating good test-retest reliability. The machine learning methods had lower sensitivity than mean clinical ratings (Figure. 1).

    Conclusions: The presented methodology was able to assess motor symptoms in PD well, comparable to movement disorder experts. The leg agility test did not reflect treatment related changes.

  • 15.
    Aghanavesi, Somayeh
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Bergquist, Filip
    Nyholm, Dag
    Senek, Marina
    Memedi, Mevludin
    Treatment response index from a multi-modal sensor fusion platform for assessment of motor states in Parkinson's disease2019Manuscript (preprint) (Other academic)
    Abstract [en]

    The aim of this paper is to develop and evaluate a multi-sensor data fusion platform for quantifying Parkinson’s disease (PD) motor states. More specifically, the aim is to evaluate the clinimetric properties (validity, reliability, and responsiveness to treatment) of the method, using data from motion sensors during lower- and upper-limb tests.

    Methods: Nineteen PD patients and 22 healthy controls were recruited in a single center study. Subjects performed standardized motor tasks of Unified PD Rating Scale (UPDRS), including leg agility, hand rotation, and walking after wearing motion sensors on ankles and wrists. PD patients received a single levodopa dose before and at follow-up time points after the dose administration. Patients were video recorded and their motor symptoms were rated by three movement disorder experts. Experts rated each and every test occasions based on the six items of UPDRS-III (motor section), the treatment response scale (TRS) and the dyskinesia score. Spatiotemporal features were extracted from the sensor data. Features from lower limbs and upper limbs were fused. Feature selection methods of stepwise regression (SR), Lasso regression and principle component analysis (PCA) were used to select the most important features. Different machine learning methods of linear regression (LR), decision trees, and support vector machines were examined and their clinimetric properties were assessed.

    Results: Treatment response index from multimodal motion sensors (TRIMMS) scores obtained from the most valid method of LR when using data from all tests. Features were selected by SR, and this method resulted in r=0.95 to TRS. The test-retest reliability of TRIMMS was good with intra-class correlation coefficient of 0.82. Responsiveness of the TRIMMS to levodopa treatment was similar to the responsiveness of TRS.

    Conclusions: The results from this study indicate that fusing motion sensors data gathered during standardized motor tasks leads to valid, reliable and sensitive objective measurements of PD motor symptoms. These measurements could be further utilized in studies for individualized optimization of treatments in PD.

  • 16.
    Aghanavesi, Somayeh
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Filip, Bergquist
    Gothenburg University.
    Nyholm, Dag
    Uppsala University.
    Senek, Marina
    Uppsala University.
    Memedi, Mevludin
    Örebro University.
    Feasibility of a multi-sensor data fusion method for assessment of Parkinson’s disease motor symptoms2018Conference paper (Refereed)
    Abstract [en]

    Title: Feasibility of a multi-sensor data fusion method for assessment of Parkinson’s disease motor symptoms

    Objective: To assess the feasibility of measuring Parkinson’s disease (PD) motor symptoms with a multi-sensor data fusion method. More specifically, the aim is to assess validity, reliability and sensitivity to treatment of the methods.

    Background: Data from 19 advanced PD patients (Gender: 14 males and 5 females, mean age: 71.4, mean years with PD: 9.7, mean years with levodopa: 9.5) were collected in a single center, open label, single dose clinical trial in Sweden [1].

    Methods: The patients performed leg agility and 2-5 meter straight walking tests while wearing motion sensors on their limbs. They performed the tests at baseline, at the time they received the morning dose, and at pre-specified time points until the medication wore off. While performing the tests the patients were video recorded. The videos were observed by three movement disorder specialists who rated the symptoms using a treatment response scale (TRS), ranging from -3 (very off) to 3 (very dyskinetic). The sensor data consisted of lower limb data during leg agility, upper limb data during walking, and lower limb data during walking. Time series analysis was performed on the raw sensor data extracted from 17 patients to derive a set of quantitative measures, which were then used during machine learning to be mapped to mean ratings of the three raters on the TRS scale. Combinations of data were tested during the machine learning procedure.

    Results: Using data from both tests, the Support Vector Machines (SVM) could predict the motor states of the patients on the TRS scale with a good agreement in relation to the mean ratings of the three raters (correlation coefficient = 0.92, root mean square error = 0.42, p<0.001). Additionally, there was good test-retest reliability of the SVM scores during baseline and second tests with intraclass-correlation coefficient of 0.84. Sensitivity to treatment for SVM was good (Figure 1), indicating its ability to detect changes in motor symptoms. The upper limb data during walking was more informative than lower limb data during walking since SVMs had higher correlation coefficient to mean ratings.  

    Conclusions: The methodology demonstrates good validity, reliability, and sensitivity to treatment. This indicates that it could be useful for individualized optimization of treatments among PD patients, leading to an improvement in health-related quality of life.

  • 17.
    Aghanavesi, Somayeh
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Fleyeh, Hasan
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Memedi, Mevludin
    Dougherty, Mark
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Feasibility of using smartphones for quantification of Parkinson’s disease motor states during hand rotation tests2019Conference paper (Refereed)
  • 18.
    Aghanavesi, Somayeh
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Memedi, Mevludin
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Dougherty, Mark
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Nyholm, Dag
    Westin, Jerker
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Verification of a method for measuring Parkinson’s disease related temporal irregularity in spiral drawings2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 10, article id 2341Article in journal (Refereed)
    Abstract [en]

    Parkinson's disease (PD) is a progressive movement disorder caused by the death of dopamine-producing cells in the midbrain. There is a need for frequent symptom assessment, since the treatment needs to be individualized as the disease progresses. The aim of this paper was to verify and further investigate the clinimetric properties of an entropy-based method for measuring PD-related upper limb temporal irregularities during spiral drawing tasks. More specifically, properties of a temporal irregularity score (TIS) for patients at different stages of PD, and medication time points were investigated. Nineteen PD patients and 22 healthy controls performed repeated spiral drawing tasks on a smartphone. Patients performed the tests before a single levodopa dose and at specific time intervals after the dose was given. Three movement disorder specialists rated videos of the patients based on the unified PD rating scale (UPDRS) and the Dyskinesia scale. Differences in mean TIS between the groups of patients and healthy subjects were assessed. Test-retest reliability of the TIS was measured. The ability of TIS to detect changes from baseline (before medication) to later time points was investigated. Correlations between TIS and clinical rating scores were assessed. The mean TIS was significantly different between healthy subjects and patients in advanced groups (p-value = 0.02). Test-retest reliability of TIS was good with Intra-class Correlation Coefficient of 0.81. When assessing changes in relation to treatment, TIS contained some information to capture changes from Off to On and wearing off effects. However, the correlations between TIS and clinical scores (UPDRS and Dyskinesia) were weak. TIS was able to differentiate spiral drawings drawn by patients in an advanced stage from those drawn by healthy subjects, and TIS had good test-retest reliability. TIS was somewhat responsive to single-dose levodopa treatment. Since TIS is an upper limb high-frequency-based measure, it cannot be detected during clinical assessment.

  • 19.
    Aghanavesi, Somayeh
    et al.
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Memedi, Mevludin
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Nyholm, Dag
    Senek, Marina
    Medvedev, Alexander
    Askmark, Håkan
    Equilonius, Sten-Magnus
    Bergquist, Filip
    Gonstantinescu, Radu
    Ohlsson, Fredrik
    Spira, Jack
    Sara, Lycke
    Ericsson, Enders
    Quantification of upper limb motor symptoms of Parkinson’s disease using a smartphone2016In: Abstracts of the Twentieth International Congress of Parkinson's Disease and Movement Disorders / [ed] Somayeh Aghanavesi, 2016, Vol. 31, p. S640-, article id 1948Conference paper (Other academic)
  • 20.
    Aghanavesi, Somayeh
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Nyholm, Dag
    Marina, Senek
    Bergquist, Filip
    Memedi, Mevludin
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    A smartphone-based system to quantify dexterity in Parkinson's disease patients2017In: Informatics in Medicine Unlocked, ISSN 2352-9148, Vol. 9, p. 11-17Article in journal (Refereed)
    Abstract [en]

    Objectives: The aim of this paper is to investigate whether a smartphone-based system can be used to quantify dexterity in Parkinson’s disease (PD). More specifically, the aim was to develop data-driven methods to quantify and characterize dexterity in PD. Methods: Nineteen advanced PD patients and 22 healthy controls participated in a clinical trial in Uppsala, Sweden. The subjects were asked to perform tapping and spiral drawing tests using a smartphone. Patients performed the tests before, and at pre-specified time points after they received 150% of their usual levodopa morning dose. Patients were video recorded and their motor symptoms were assessed by three movement disorder specialists using three Unified PD Rating Scale (UPDRS) motor items from part III, the dyskinesia scoring and the treatment response scale (TRS). The raw tapping and spiral data were processed and analyzed with time series analysis techniques to extract 37 spatiotemporal features. For each of the five scales, separate machine learning models were built and tested by using principal components of the features as predictors and mean ratings of the three specialists as target variables. Results: There were weak to moderate correlations between smartphone-based scores and mean ratings of UPDRS item #23 (0.52; finger tapping), UPDRS #25 (0.47; rapid alternating movements of hands), UPDRS #31 (0.57; body bradykinesia and hypokinesia), sum of the three UPDRS items (0.46), dyskinesia (0.64), and TRS (0.59). When assessing the test-retest reliability of the scores it was found that, in general, the clinical scores had better test-retest reliability than the smartphone-based scores. Only the smartphone-based predicted scores on the TRS and dyskinesia scales had good repeatability with intra-class correlation coefficients of 0.51 and 0.84, respectively. Clinician-based scores had higher effect sizes than smartphone-based scores indicating a better responsiveness in detecting changes in relation to treatment interventions. However, the first principal component of the 37 features was able to capture changes throughout the levodopa cycle and had trends similar to the clinical TRS and dyskinesia scales. Smartphone-based scores differed significantly between patients and healthy controls. Conclusions: Quantifying PD motor symptoms via instrumented, dexterity tests employed in a smartphone is feasible and data from such tests can also be used for measuring treatment-related changes in patients.

  • 21.
    Aghanavesi, Somayeh
    et al.
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Westin, Jerker
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    A review of Parkinson’s disease cardinal and dyskinetic motor symptoms assessment methods using sensor systems2016Conference paper (Refereed)
    Abstract [en]

    This paper is reviewing objective assessments of Parkinson’s disease(PD) motor symptoms, cardinal, and dyskinesia, using sensor systems. It surveys the manifestation of PD symptoms, sensors that were used for their detection, types of signals (measures) as well as their signal processing (data analysis) methods. A summary of this review’s finding is represented in a table including devices (sensors), measures and methods that were used in each reviewed motor symptom assessment study. In the gathered studies among sensors, accelerometers and touch screen devices are the most widely used to detect PD symptoms and among symptoms, bradykinesia and tremor were found to be mostly evaluated. In general, machine learning methods are potentially promising for this. PD is a complex disease that requires continuous monitoring and multidimensional symptom analysis. Combining existing technologies to develop new sensor platforms may assist in assessing the overall symptom profile more accurately to develop useful tools towards supporting better treatment process.

  • 22.
    Agirman, Nesim
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Ali, Mustafa
    Dalarna University, School of Technology and Business Studies, Construction.
    U-värde av isoleringsmaterial i en kassett: En experimentell jämförelse mellan en fönsterkassett som har isolering och en utan isolering2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Insulation and insulation material is one of the most important components in the construction industry and has a wide range of applications and therefore the demand is huge. Because of the high costs on the market, new and different researches take place every day to find alternative insulation materials. The technology make the opportunities greater to find and use cheaper materials. Therefore, it is not un common to see insulations made of different materials every day.

    The purpose of this study is to investigate two Moniflexcassettes, one with insulation and one without, in a climate chamber, to then compare their u-values.

    The results showed the influence on the insulation, that the u-value was lower on the cartridge with the insulation, and therefore a proof that the insulation can use as an additional insulation. This applied especially for windows and glass portions who have a high u-value, which mean that windows and glass portions do not have to change to newer windows with lower u-values.

    The company Isolight´s current u-value of the cassette with the isolation was not the same as with the tested U-value in Högskolan Dalarnas climate chamber. On the cassette without insulation, there has been no comparison between the tested value and the value of the company because the company does not have a u-value for that.

  • 23.
    Ahamed, Anees
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Accelerated Aging of First-surface Enhanced Aluminum Solar Reflectors under Damp Heat Conditions2016Independent thesis Advanced level (degree of Master (Two Years)), 25 credits / 37,5 HE creditsStudent thesis
    Abstract [en]

    Solar reflectors are one of the main components of concentrating solar power systems. With new products being developed, durability studies become a necessity for assessing the feasibility of commercial application. In this project, accelerated aging of three types of first-surface enhanced aluminum reflectors and one type of second-surface silvered thick glass mirror under damp heat conditions is studied. The project is conducted at the Plataforma Solar de Almería (PSA), in collaboration with German Aerospace Center (DLR), and Center for Energy, Environment and Technology (CIEMAT), Spain.

     

    The study is centered on analyzing the effect of soiling on degradation of reflectors. In addition to conventional methods, space resolved specular reflectometry is utilized for comparative purpose. Damp heat test conditions are simulated in a climatic test chamber. Test is conducted with reference to International Electrotechnical Commission standard IEC 62108 10.7a: damp heat test guidelines. The reflector samples are artificially soiled with natural and synthetic test sands of varying composition. Reflector performance is assessed based on the reduction in monochromatic specular reflectance.

     

    From the tests, a comparative assessment of the candidate reflectors is obtained. Aluminum samples suffered higher degradation than silvered glass mirrors. Aluminum reflectors with polymer top coat permanently retained soil residue. It is observed that presence of chlorides and organic components caused corrosion on all the types of reflectors tested. Surface roughening is the reason for performance deterioration in most of the cases. By comparing different reflectance measurement methods, the significance of total area of the measurement spot in the measurement procedures could be highlighted. It is suggested that for studies involving artificial soiling, the grain size of sand is to be factored in.

  • 24.
    Ahmadi Moghadam, Parham
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Steel Sheet Applications and Integrated Heat Management2016Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Increasing energy use has caused many environmental problems including global warming. Energy use is growing rapidly in developing countries and surprisingly a remarkable portion of it is associated with consumed energy to keep the temperature comfortable inside the buildings. Therefore, identifying renewable technologies for cooling and heating is essential. This study introduced applications of steel sheets integrated into the buildings to save energy based on existing technologies. In addition, the proposed application was found to have a considerable chance of market success.

    Also, satisfying energy needs for space heating and cooling in a single room by using one of the selected applications in different Köppen climate classes was investigated to estimate which climates have a proper potential for benefiting from the application. This study included three independent parts and the results related to each part have been used in the next part.

    The first part recognizes six different technologies through literature review including Cool Roof, Solar Chimney, Steel Cladding of Building, Night Radiative Cooling, Elastomer Metal Absorber, and Solar Distillation. The second part evaluated the application of different technologies by gathering the experts’ ideas via performing a Delphi method. The results showed that the Solar Chimney has a proper chance for the market.

    The third part simulated both a solar chimney and a solar chimney with evaporation which were connected to a single well insulated room with a considerable thermal mass. The combination was simulated as a system to estimate the possibility of satisfying cooling needs and heating needs in different climate classes. A Trombe-wall was selected as a sample design for the Solar Chimney and was simulated in different climates. The results implied that the solar chimney had the capability of reducing the cooling needs more than 25% in all of the studied locations and 100% in some locations with dry or temperate climate such as Mashhad, Madrid, and Istanbul. It was also observed that the heating needs were satisfied more than 50% in all of the studied locations, even for the continental climate such as Stockholm and 100% in most locations with a dry climate. Therefore, the Solar Chimney reduces energy use, saves environment resources, and it is a cost effective application. Furthermore, it saves the equipment costs in many locations. All the results mentioned above make the solar chimney a very practical and attractive tool for a wide range of climates.

  • 25.
    Aishwarya, Veena Aishwarya
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Effects of Soling on the Solar Radiation Sensors for Indian Climatic Conditions2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The satisfaction and elation that accompany the successful completion of any task

    would be incomplete without the mention of the people who have made it possible. It is a great

    privilege to express my gratitude and respect to all those who have guided me and inspired me

    during the period of the project work.

    First and foremost, I express my sincere gratitude to my University professor

    Fiedler Frank, Program Coordinator, Dalarna University, Borlange, Sweden who encouraged

    and permitted me to have my project in the second semester itself.

    I owe a lot to my supervisor Rönnelid Mats, Associate Professor of Energy and

    Environmental Technology, Dalarna University, Borlange, Sweden for his valuable

    suggestions, constructive criticism and encouragement for the project.

    I deem it to be a great privilege in thanking my external supervisor Dr.Richard

    Meyer, Founder and Managing Director (Suntrace GmbH) and Marko Schwandt, Advisor, Solar

    Expert en Suntrace GmbH for giving an opportunity to work under him. Their guidance,

    academic freedom and co-operation have helped me in completing my project.

    My heartfelt thanks to Dr. S. Gomathinayagam, Director General, NIWE and Dr.G.Giridhar,

    Deputy Director General & Head, SRRA department, NIWE for providing me the necessary

    facilities for the completion of my masters project. I am indebted to Dr.Indradip Mitra,Senior

    Technical Advisor at GIZ GmbH and Kaushal Chhatbar, Project Manager, Project

    Development at Suntrace GmbH , for their valuable suggestions and support.

    I also pay my sincere regards to the staffs of SRRA department for their support

    during the period of my project. I owe a lot to my family, who always motivated me and brought

    me to this level. Finally I submit my obeisance to THE ALMIGHTY for constantly supporting

    me and blessing me with the necessary strength to carry out this research.

  • 26. Akenine, Daniel
    et al.
    Stier, Jonas
    Dalarna University, School of Humanities and Media Studies.
    Människor och Ai: En bok om artificiell intelligens och oss själva2018 (ed. 1)Book (Other (popular science, discussion, etc.))
  • 27.
    Alayan, Sophia
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Design of a PV-Diesel Hybrid System with Unreliable Grid Connection in Lebanon2016Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is a study on integration of photovoltaic generators into an existing diesel-unreliable grid connected system at the Lebanese village of Khiam. The main goal of implementing PV-diesel hybrid system is to reduce diesel consumption and the import of fossil fuel used in electricity power supply. Before designing the system, it is necessary to create a load profile for 120 households and pre-design the size of the PV generator, the capacity of storage system and inverter type/size selection. The load profile data is based on the average of monthly energy consumption gathered from Khiam village households.

    Detailed simulations and financial analysis are performed with HOMER to compare different systems and their viability. The simulations include four different designs starting from the existing system, diesel generator with unreliable grid, followed by PV generator and unreliable grid, PV and diesel generator and ended with the complete hybrid system. Once the Hybrid system is determined a detailed design is done to optimize the lowest cost PV-diesel hybrid system. The final simulated PV-diesel hybrid system is suggested with a PV capacity of 270 kWp, existing diesel capacity with 200 kVA, an inverter output of 115 kW and battery bank nominal capacity is 1872 kWh. The system renewable fraction is 53% and the project life cycle is 25 years. The PV-diesel hybrid system is projected to produce electricity at a cost of 0.12 USD/kWh. This cost is significantly lower than the 0.26 USD/kWh paid to the diesel operator, as well as lower than 0.13 USD/kWh paid to the utility grid.

    In addition, and according to the given information from the owner, an estimated diesel consumption of 104000 ltr/year, the simulation result shows diesel consumption at 40000 ltr/year. The reduced carbon dioxide production by 65%, from 776 to 272 tons per year, provides further justification for the PV installation in a commercial PV-diesel hybrid system.

  • 28.
    Albatrok, Husam
    Dalarna University, School of Technology and Business Studies, Construction.
    Våningspåbyggnad i trä på befintligt betong bostadshus2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    During the years 1965–1975, the politicians chose to start a large housing development, which resulted in a million homes being built in 10 years. It was called Miljonprogrammet. Tjärna Ängar is an area located in Borlänge where some of those building took place. The area has 1,179 apartments in 3-storey slab houses and the Tjärna Angar area is divided into three different blocks: Kornstigen, Klövern and Plogstigen. These are built next to Tjärna center, with good bus connections to the rest of Borlänge.

    The purpose of this work was to produce a storey building for an existing slab of concrete. the reference building is at Kornstigen 25.

    With the help of Drawings, the existing building will be studied. Information search will be done on the subject regarding floor buildings and the history of the million program and construction. Walls and ceilings will be developed and an extension for the lift. Finally, a model is made in a Cad-programe that illustrates the result.

    The result of the storey building was a wooden walkway with a total of 10 apartments. Two corner apartments became three rooms and the kitchen while the rest became two rooms and kitchens in varying surfaces. Storey building wood is a good way to be able to build on the heigt, but many aspects considered and be and checked before a storey buildig takes place.

  • 29.
    Alfadel, Usama
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Analysing the Peak Shaving Effect and the Increase in SelfConsumption and Self Sufficiencyof Battery Storage When Coupledto a Single Family House2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aims of the study were to investigate the increase in self-consumption and self-sufficiency and the peak shaving effect of batteries when added to a PV system dimensioned to supply the electric demand of a low energy house built in Sweden. The simulated batteries were Li-ion and the study had a 15-minutes temporal resolution. The study took only the technical aspect of batteries into account and disregarded the economic aspect. A data set of measurements from two near-zero-energy houses built by the Research Institute of Sweden (RISE) was used as inputs. The first house provided measured load profile for an automated load and measured PV production from its 3.6 kW

    p system, the second house provided a load profile for a normal human interactive load. The measured PV production from the 3.6 kWp PV system was compared to the PV production from a simulated 3.6 kWp system taken from PVsyst and System Advisor Model (SAM) and by using different weather data profiles for the simulations. The global irradiance values from the used weather profile data were compared to demonstrate the difference in its values and its effect on the simulated PV production. This comparison between the measured PV production and the simulated one was done because most of the PV simulation software does not take measured PV production as input but they simulate their own PV production based on their built-in weather data; including the software used in this study SAM. The first house with the automated load had an annual energy consumption of Ca. 3600 kWh / Year. The second house with its human interactive load had an annual energy consumption of Ca. 6000 kWh / Year. The load profile was taken as a whole and then divided to different types; heat pump, ventilation and remaining load which represents house hold services. The effect of the input load profile types and its temporal resolution was clarified; this effect came in consistency to what was concluded from the literature review. Different simulations were done varying battery sizes, voltage level, coupling method, dispatch algorithm and other parameter. Three different dispatch algorithms were used for the simulations; two are designed for peak shaving and are built-in tools in SAM while the third algorithm is called Target Zero and designed for maximizing self-consumption and self-sufficiency, it was found in a reference so it was executed in MS Excel. Each of the algorithms used was found to affect both the peaks and the self-consumption and self-sufficiency of the system after adding the batteries compared to before, one as a major effect and the other as a byproduct effect. The peak shaving results varied by varying the batteries and the dispatch algorithm used, for the peak shaving algorithms from SAM, a general decrease in peaks value was reached. For the Target Zero algorithm which optimizes on self-consumption and self-sufficiency, a decrease in the number of the peaks was reached. Both decreases happened by increasing battery sizes. For the self-consumption and self-sufficiency effect, an increase happened with its highest value for 7.2 kWh batteries and by using the three different algorithms. The effect of the load type was also demonstrated by comparing the simulations results for the heat pumps from both houses since both heat pumps were found to have the highest effect on the results. The study was concluded by emphasizing the added values of batteries when coupled to a behind-the-meter PV system. The study could have been more precise and added more information to this field if it had a 1 minute temporal resolution simulations, but patching one minute temporal resolution load profile takes a long time. Working with one minute load profile requires one minute weather profile for the PV simulation which is normally only commercial. Also, having a weather station installed at the house to measure the solar irradiance to be used in the simulation instead of using different weather profiles would have added more accuracy to this paper.

  • 30.
    Alfredsson, Clara
    et al.
    Dalarna University, School of Technology and Business Studies, Graphic Arts Technology.
    Pettersson, Karin
    Dalarna University, School of Technology and Business Studies, Graphic Arts Technology.
    Sportevenemangets nyhetsbrev: Råd om utformningen av nyhetsbrev2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Society is becoming more digitized, which has led to that several companiesneed to change their marketing. Many companies promote themselves throughdigital channels, one of these are e-mail. A way to market themselves throughe-mail is with newsletters. The research on e-mail marketing is far morecomprehensive than the research specifically about newsletters, which makesnewsletters to an interesting subject to study more closely. The study aims toexamine what advice regarding the design of the newsletter covers and if theadvices is suited specifically for sports events newsletters. The study also aimsto examine if FIS Nordic World Ski Championship's public newsletters followsthe selected advices and if it prefers of the receivers.To answer the questions of this study, an identification, a comparison and asurvey has been done. The identification was done through an informationsearch and 65 advices were found. Six general advice were selected andcompared to the Nordic Ski Championship's public newsletters. New modifiedversions of parts of the newsletters were created based on whether theyfollowed the six general advices or not. The modified versions and the originalversions were put together as pairs. In the survey that was published on aFacebook page and group administered by the Nordic Ski Championships,participants selected which version they preferred. The identification resulted inthat many of the advices covered the design of the newsletters text and advicesuited specifically for sport events was rare. The Nordic Ski Championshipsnewsletters followed four of the six general advices and the version of thenewsletters that followed the advice was preferred in three of six cases.

  • 31.
    Alhamwi, MHD Mouaz
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Evaluating the Economic Feasibility for utilizing PV Power Optimizers in Large-scale PV Plants for The Cases of Soiling, Mismatching, and Degradation2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The solar PV modules are influenced by a variety of loss mechanisms by which the energy yield is affected. A PV system is the sum of individual PV modules which should ideally operate similarly, however, inhomogeneous soiling, mismatching, and degradation, which are the main focus in this study, lead to dissimilarities in PV modules operating behavior and thus, lead to losses which will be assessed intensively in terms of energy yield.

    The dissimilarities in PV modules are referred to the ambient conditions or the PV modules

    characteristics which result in different modules’ maximum power point (MPP) and thus, different currents generated by each PV modules which cause the mismatching. However, the weakest PV module current governs the string current, and the weakest string voltage governs the voltage.

    Power optimizers are electronic devices connected to the PV modules which adjust the voltages of the PV modules in order to obtain the same current as the weakest module and thus, extract

    the modules’ MPP. Hence, the overall performance of the PV plant is enhanced. On the other hand, the power optimizers add additional cost to the plant’s investment cost and thus, the extra energy yield achieved by utilizing the power optimizers must be sufficient to compensate the additional cost of the power optimizers. This is assessed by designing three systems, a reference system with SMA inverters, a system utilizes Tigo power optimizers and SMA inverters, and a system utilizes SolarEdge power optimizers and inverters. The study considers four different locations which are Borlänge, Madrid, Abu Dhabi, and New Delhi.

    An Excel model is created and validated to emulate the inhomogeneous soiling and to evaluate the economic feasibility of the power optimiz

    ers. The model’s inputs are obtained from PVsyst and the precipitation data is obtained from Meteoblue and SMHI database.

    The economic model is based on the relation between Levelized Cost of Electricity (LCOE) which will be used to derive the discount rate. Graphs representing the discounted payback period as a function of the feed-in tariff for different discount rates is created in order to obtain the discounted payback period.

    The amount of extra energy yielded by the Tigo and the SolarEdge systems is dependent on the soiling accumulated on the PV modules. Relative to the reference system, 6.5 % annual energy gain by the systems utilizing the power optimizers in soiling conditions, up to 2.1 % in the degradation conditions, and up to 9.7 % annual energy gain at 10 % mismatching rate. The extra energy yield is dependent on the location, however, the Tigo and the SolarEdge systems have yielded more energy than the reference system in all cases except one case when the mismatch losses is set to zero.

    The precipitation pattern is very influential, and a scare precipitation leads to a reduction in the energy yield, in this case, the Tigo and the SolarEdge systems overall performance is enhanced and the extra energy gain becomes greater.

    The Tigo system yield slightly more energy than the SolarEdge system in most cases,

    however, during the plant’s lifetime, the SolarEdge system could become more efficient than the Tigo system which is referred to the system’s sizing ratio. The degradation of the system or the soiling accumulation decreases the irradiation and thus, a slightly oversized PV array become suitable and deliver an optimal power to the inverters.

    The SolarEdge system is feasible in all scenarios in terms of LCOE and discounted payback period, although its slightly lower performance relative to the Tigo system, this is referred to its low initial cost in comparison to the other systems. The Tigo system is mostly infeasible although it yields more energy than the reference and the SolarEdge systems, this is referred

    iii

    to its relatively high initial cost. However, feed-

    in tariffs higher than 20 € cent / kWh make

    all systems payback within less than 10 years.

    The results have overall uncertainty within ± 6.5 % including PVsyst, Excel model, and the

    precipitation uncertainties. The uncertainty in the degradation and the mismatching

    calculations is limited to PVsyst uncertainty which is ± 5 %. The uncertainties in LCOE in

    the location of New Delhi, since it is the worst-case scenario, are 5.1 % and 4 % for the

    reference and the systems utilizing power optimizers, respectively.

    Consequently, accommodating the uncertainties to the benefits gained by utilizing power

    optimizers indicates that the energy gain would oscillate in the range of 6 % - 6.9 % for the

    soiling calculations, 2 % - 2.2 % for the degradation simulations, and 9.2 % - 10.2 % for the

    mismatching simulations at 10 % mismatchrate.

  • 32.
    Al-Hashimi, Mazin
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Modelling Installation Cost for Rooftop PV Systems2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The cost of installation of photovoltaic (PV) systems is a substantial fraction of the total cost of the project and the same is increasing with reducing cost of PV modules. This study essentially deals with the cost of installation of rooftop PV systems and presents a cost model for it, based on data collected for more than 700 projects of different capacities, roof types, circumstances, and locations in Sweden. The presented cost model shall give reasonably accurate estimations about the costs associated with the main elements of the process of rooftop PV systems installation, such as labour, shipping, equipment, travel, and accommodation, for different situations as a function of few important variables such as system capacity, roof type, distance to the installation location, etc. The weighted share of cost of the different elements of the cost model out of the total cost of installation was determined. Several relationships between different elements and variables were examined to find relationships that can help to better understand the process of installation and to develop the cost model. The variations in time required per unit system capacity have been examined for several processes of rooftop PV systems installation, to investigate about potential for reduction in the time and thus the cost due to economies of scale.

  • 33.
    Ali, Samir
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Hanna, David
    Dalarna University, School of Technology and Business Studies, Construction.
    Hjälpmedel till resenärer i kollektivtrafiken som inte kan ta till sig vanliga skyltar på ett enkelt sätt2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report aims at investigating how traffic management can help disabled and elderly. Although more than 800,000 people travel with SL every day, many elderly and disabled find it difficult to travel using public transportation. Through interviews, different associations representing different disabilities have reported that they feel a lack of information and they feel insecure. Many choose not to travel with public transportation. The investigation has resulted in two different solutions, the advantages and disadvantages of the different solutions are discussed as well. A WEFEEL bracelet that communicates with both the passenger and the bus driver via signals to facilitate the perception that the correct bus is on its way, signal if the traveller has a need for assistance, etc. The second solution proposal WEFIND is ground plates with diodes in the form of arrows that show the path when traffic disturbances occurs and redirects the passengers. Both solutions work for many different groups and also for travellers without special needs (arrows). The solutions take into consideration the environmental issue but have not been further investigated in terms of instalment and economy. The conclusion is that the suggested solutions can help travellers feel safer and thus travel more using public transport.

  • 34.
    Alkhado, Luqman
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Boussaa, Youcef
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Heat transfer tests on EPS material and massive timber wall component2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Timber walls are known to be an energy efficient component in the building envelope.

    These building elements are essential in the passive design and have been pointed out to

    their ability to regulate the indoor climate and reduce energy demand. Heat transfer

    measurements of thermal transmittance value of Iso-timber wall component have been

    performed with the climate chamber at three temperature differences. The influence of

    temperature variations on the thermal conduction of the wall were investigated. The

    temperature on the warm side was kept at room temperature 20 °C while the cold side

    temperature was decreased from 0 C to -20 C during the tests. As the temperature

    difference is increased, the thermal transmittance value of the timber wall component

    decreased slightly due to decrease in the thermal conductivity value. The effect of density

    and porosity on the thermal conductivity may be related to the presence of air voids and

    cell boundaries inside the timber wall. Results have showed that the U-value of the timber

    wall component decreases at higher temperature differences which indicates the higher

    degree of insulation of the timber wall component.

  • 35.
    Almsalati, Hussam
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Life cycle assessment of villas made by Fiskarhedenvillan, comparison between wood and brick facade2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Awareness of climate change has resulted in enormous challenges for developed and

    developing countries. The frightening truth about our environmental situation has led to

    investigations of the causes of these changes and to obstruct these sources gradually but

    quickly. The alarming increase of average temperature of the earth has caused much worry

    around the world. Gas emissions in the atmosphere greatly affect the environment, where

    CO

    2 emissions is one of the most serious factors contributing to the global warming

    potential. As the building sector emits 40% of global energy use and one-third of global

    greenhouse gas emissions, engineers must be educated to choose the best materials that

    lead to reducing CO

    2 emissions. This means selecting materials that have less negative

    impact on the environment and are more “environmentally friendly”.

    This study shows how much CO

    2e emissions are released into the atmosphere from a

    wooden structure villa that consists of two stories, a storage and a garage, with a total area

    of 229.6m2. The results of this case will be compared to a second case, where the external

    wooden siding is replaced with brick veneer. This result of this comparison provides us

    with a guideline in for how the selected materials impact the environment, illuminating the

    importance in choosing the right materials according to their CO

    2e emission levels. In this

    way, the building sector can actively work to reduce the environmental impact.

    To achieve these goals, this study performed via life cycle assessment LCA methodology

    by using the One-Click LCA program. LCA is identified as a technique to assess the

    environmental impact and resources used through a product’s life cycle. This study utilized

    the LCA methodology (cradle to grave), which means starting from the extraction of raw

    materials, to product production, manufacturing, product usage and its end of life. The

    study lifespan was estimated to be 50 years.

    The results of the study verify that the wooden villa is more environmentally friendly than

    the villa made of brick, where carbon dioxide equivalent emission can be reduced to more

    than half by utilizing wood. Implementing the life cycle assessment study to any building

    aids in making the decision to choose the right materials for building according to CO

    2e

    emission. And in this way, the environmental impact caused by the building sector will be

    greatly reduced.

  • 36.
    Al-Samahiji, Alexander
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Incorporating Solar Energy Into an Aluminium Smelter’s Energy Mix: A study using Aluminium Bahrain2017Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis was aimed at studying the possibility of integrating solar energy in to an existing aluminium smelter in the Kingdom of Bahrain owned by Aluminium Bahrain (ALBA). The smelter was powered by its own in-house natural gas fed power plants. ALBA was chosen as the subject of the study for of two reasons. Firstly, the power station at ALBA was similar in technology to those powering the national grid. Secondly, the nominal power of ALBA was not dissimilar to that of the national grid. This meant that the techniques and technologies investigated were useful in the context of the national grid as well. A literature review was initially conducted to better understand how the current aluminium smelters work, what the possibilities were for introducing solar energy and what has been done previously. The study used publically available information to deduce the energy consumption of the ALBA smelter on an annual basis. For the year 2011 this was found to be in the order of 15.2TWh when ALBA had 2,249MW of nominal plant capacity installed and had consumed about 132MMBCF of natural gas. With the planned pot-line 6 expansion an additional 1,792MW capacity would be added with the corresponding additional gas use and increased energy output. The completion of pot-line 6, scheduled for Q1 2019, would also make ALBA the world’s largest single-site aluminium smelter.  This energy demand information was then used with PVSyst and System Advisor Model simulation software. The aim was to determine what photovoltaic (PV) and concentrated solar power (CSP) energy plants capable of meeting ALBA’s needs would be in terms of power, energy outputs and land usage. Although powering a modern aluminium smelter is possible with today’s solar technology, the area of land required would be very large. It was deduced that using PV fixed tilt arrays, a PV plant of 9.2GWp would be required to deliver the annual energy requirements of ALBA covering a theoretical land area of some 200km2. Utilising CSP plants of central tower and concentric heliostat design would need about 358km2 whereas parabolic trough collector technology would need about 240km2. However a CSP plant utilising linear Fresnel collectors would need about 105km2 of land area. These contiguous land areas are not available in the Kingdom of Bahrain and so alternatives would have to be studied for locating such plants. Another issue would be to find a robust and reliable storage technology to power the plant during the evenings and other times of low solar resource.  It was found that the existing roof areas of ALBA’s pot-lines and cast house would be sufficient to house a PV plant of 6.5MWp utilising standard 250Wp PV modules. This would be larger than the largest plant currently installed in the country which stands at 5MWp developed by Bapco. The plant would produce some 9.7GWh of energy per average year and could be utilised by ALBA. Alternatively, the PV plant could be connected directly to the national grid and thus provide another source of income to ALBA whilst helping in the national drive for harnessing renewable energy. It should be noted that there are more suitable roof areas available at ALBA meaning that the PV plant size could be larger and if more powerful modules are used, the nominal plant capacity would also be increased delivering more annual energy. Due mainly to time constraints, it was not possible to investigate some areas that were highlighted during the course of the study. These included plant costs, energy storage options, modelling and simulating CSP derived heat injection into gas power turbines, water usage requirements and mitigation techniques and the technologies for maintaining the collectors clean and reflective in the harsh desert climate of the country. These are all areas for further work.

  • 37.
    Alzén, Axel
    Dalarna University, School of Technology and Business Studies, Mechanical Engineering.
    Effektivisering av en produktionsprocess: Analys och förbättringsförslag till en verkstadsindustri2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Isakssons AB is the manufacturer of custom-designed products and efficient solutions in stainless steel, constructional metalwork and environmental technology. The company is currently going through an expansion phase, which leads to greater requirements for the production. In order to cope with this expansion, they have chosen to rebuild their premises, and these changes must be adapted for the production to enable further growth for the company.  The purpose of this study is to give improvement proposals to a more effective production process at a manufacturing company with varying products. In order to create understanding for the process, flowcharts, process mapping’s and time studies have been executed. By performing a zero state analysis, improvement opportunities have been discovered, and changes have been proposed from these.  The results from the frequency studies show that the operators spend a lot of time on work that is non valuable for the product. By creating more workstations for manufacturing and introducing visual workplace aids, these non valuable activities can be reduced. Furthermore, the re-locating of machines and inventory have been suggested, in order to create an easier flow through the premises.

  • 38.
    Andersen, Martin
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. Chalmers University of Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Dalenbäck, Jan-Olof
    Chalmers University of Technology.
    Techno-Economic Analysis of Solar Options for a Block Heating System2016In: Conference Proceedings: Eurosun 2016, Palma De Mallorca: International Solar Energy Society, 2016, , p. 16Conference paper (Refereed)
    Abstract [en]

    An innovative small solar district heating system with one central heating plant and four solar substations has been built in Vallda Heberg, Sweden, to supply a new housing area with passive houses. The target solar fraction was 40% and the total system design, including heat distribution in the buildings, was based on previous experience and aimed to be simple and cost-effective. The main aim of this study was to determine whether the system can be designed in a more effective manner by change of distribution system and load density. TRNSYS models were calibrated against measured data and then used to predict the energy performance. Results indicate that lower distribution heat losses can be obtained by change to a distribution concept with lower operating temperatures, while potentially reducing cost. Changes in heat density cause reduced distribution losses and boiler supplied heat demand, with only minor effects on solar system yield.

  • 39.
    Andersson, Adam
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Berggren, Pontus
    Dalarna University, School of Technology and Business Studies, Construction.
    Utvärdering av träbjälklag i ett äldre flerbostadshus med avseende på stegljud och nedböjning: Mätningar och möjliga åtgärder och åtgärdsförslag2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    New buildings will only maginally contribute to future quantity of residential housing. Therefor new knowledge of past building technics are required, to asses which action propsals are suitable when interventions are considered. Objective. This study aims to evaluate lightweight timber joist floors in a multi-story residential building from 1903, with regard to footfall noise and deflection. Method. Data has been collected with a survey and through measurements of footfall noise and deflection. The purpose of the survey is to evaluate the residentals subjective perception of footfall noise and deflection. Footfall noise has been measured with a tapping machine in accordance with Swedish Standards. The deflection has been measured with Leica NA2 paired with a parallel-plate micrometer, GFS1, for precise leveling assessment. Results. The survey shows that the residents don’t experience any issues with regard to footfall noise and deflection. The measurements show a L’nT,w+CI,50-2500 level of 55 dB and an average deflection of 0.320 mm/kN. Conclusion. Footfall noise- and deflection levels satisfy today’s requirements according to Swedish Standards and therefor the results doesn’t motivate any action proposals or interventions.

  • 40.
    Andersson, Carolin
    Dalarna University, School of Technology and Business Studies, Mechanical Engineering.
    Från oljehydraulik till vattenhydraulik: Utveckling av ett portabelt hydraulikaggregat2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The report describes the work behind the development of a portable water hydraulic system that will be used to open and close a floodgate if the regular hydraulic system used for this is inoperative. The aim was to achieve the same performance as a portable oil hydraulic system, which could be achieved with the exception that oil could not be avoided completely.

    The project was carried out in collaboration with Mobin Hydraulic AB, which develops hydraulic systems for opening and closing floodgates. Mobin specializes in water hydraulics, which is a more environmentally friendly alternative compared with oil hydraulics. As an interest was also on the market where eco-friendly solutions were increasingly demanded, the portable water hydraulic system was of interest to both Mobin and the market.

    The problems were about how the flow was to be controlled and what pump and hydraulic engine could be used in the system. The components would be adapted to water and harmonize with a predetermined petrol engine while delivering desired performance.

    By studying hydraulics and water properties and impact on the hydraulic system in combination with taking part in Mobin's experience, an image of the system's structure and components was created.

    Based on a component search, calculations and design of concepts a concept selection was made where the selected components, component dimensions and placements in the system were displayed. Due to the limited availability of water hydraulics components, gearboxes were used to get the right speed and torque. One of the gearboxes contained oil and therefore it was not possible to completely avoid oil use.

  • 41.
    Andersson, David
    Dalarna University, School of Technology and Business Studies, Mechanical Engineering.
    Effektiviserad balresthantering2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Arctic Paper Grycksbo is a company that produces paper. The pulp which is used to produce the paper is purchased. The pulp arrives to Arctic Paper in bales which are wrapped with something called wrapping paper. The wrapping paper is similar to the pulp inside of the wrapping, which means it can be used to produce paper. Damage on the bales due to transportation and handling leads to usable pulp being removed from the bales which falls to the ground. The pulp which is removed from the bales remains on the ground (pulp rests) until workers pick it up and place it in a recycling container. This container is then to be emptied and the pulp recycled, if the procedure is working as intended.

    The current recycling procedure has proven to be in need of improvement. This has led to a need of an improvement, either by improving the method/procedure to recycle the pulp, or through preventing the pulp being removed from the bales in the first place. The purpose with this thesis is to investigate- and suggest solutions to which possibilities for improvements there is.

    An investigation of which alternative to achieve this improvement is the better- and calculations of the annual recycling potential has been done. Different concepts has then been generated based on information gathered from the investigation and calculations.

    A new way of handling the pulp which is to be recycled has been suggested in consultation with technicians from Arctic Paper. The suggested new method/procedure enables easier recycling in terms of manual labour and reduces the total costs of the procedure.

  • 42.
    Andersson, Grober
    Dalarna University, School of Technology and Business Studies, Mechanical Engineering.
    Framdrivningssystem för Articulated Funiculator i SL deep station: Framtagning och urval av koncept2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis has been carried out in collaboration with Tyréns project Articulated Funiculator developing emerging vertical transport which in this case is meant to be used in SL deep station in Stockholm.The aim of this work is to is to develop propulsion concepts for Articulated Funiculator and through concept selection sort out the optimum for SL deep station. To achieve the purpose, studies have been undertaken of literature and reports followed by workshops and customer surveys. Then a pairwise comparison has been made, QFD, concept generation and a two-stage concept selection made.Result is that the optimum propulsion system for SL deep station in Stockholm is a system of linear motors mounted between the tracks.

  • 43.
    Andersson, Ing-Marie
    et al.
    Dalarna University, School of Technology and Business Studies, Occupational science.
    Hedlund, Ann
    Dalarna University, School of Technology and Business Studies, Occupational science.
    Arbetsmiljö vid service- och reparation av skogsbränslemaskiner2013Report (Other academic)
    Abstract [sv]

    Syftet med denna studie är att ta fram underlag till en arbetsmiljöchecklista för service och reparationsarbete av skogsbränslemaskiner. Däri ingår maskiner för skördning, transport och sönderdelning av sortimenten GROT (grenar och toppar), stubbar respektive klenskog. En avgränsning har gjorts till service och reparationsarbete som görs ute i fält. Tjugotre riktade fallstudier har genomförts i Mellansverige med fokus på service- och reparationsarbete som skett ute i fält. Arbetsmiljöfaktorer har observerats och dokumenterats med foto, samtal har förts med förare och servicemän, och mätningar av buller och damm har genomförts. Vid samtal med förare har efterfrågats hur ofta service och reparationsarbete genomförs, vem som gör det, vilka moment som ingår samt var det vanligtvis utförs. Servicearbete ingår i förarens arbetsuppgifter och förekommer med olika intervall. Vissa arbetsmoment utförs dagligen, såsom byte av huggstål, smörjning av krannipplar och renblåsning av container. Andra sker med längre intervall, såsom byte av oljor och filter. I studien har tillvägagångssätt och arbetsmiljörisker vid omfattande, respektive mindre, service- ochreparationsarbete identifierats. Service- och reparationsarbete är ofta tungt och smutsigt.Arbetsmiljörisker samt goda exempel på lösningar för olika typer av maskiner har sammanställts.Baserat på studiens empiriska resultat, genomförda litteraturstudier och analyser harcheckpunkter som bör ingå i en arbetsmiljöchecklista identifierats. Identifierade checkpunkternahar grupperats utifrån målgrupp och typ av arbetsmoment med syftet att vara praktisktanvändbara. Målgrupperna är maskintillverkare/ägare som modifierar maskiner, respektiveservicemän och förare. Framtagna checkpunkter utgör en grund till en checklista för arbete medservice- och reparationsarbete av skogsbränslemaskiner.

  • 44.
    Andersson, Ing-Marie
    et al.
    Dalarna University, School of Technology and Business Studies, Occupational science.
    Rosén, Gunnar
    Dalarna University, School of Technology and Business Studies, Occupational science.
    Video exposure monitoring for transfer of knowledge in chemical hazards to small enterprises2014In: Small Enterprise Research: The Journal of SEAANZ, ISSN 1321-5906, Vol. 21, no 2, p. 223-228Article in journal (Refereed)
  • 45.
    Andersson, Linnea
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Ekeblad, Jenny
    Dalarna University, School of Technology and Business Studies, Construction.
    Energieffektivisering av klimatskal - miljonprogrammets flerbostadshus: Tjärna Ängar, Borlänge2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    During The Million Homes Programme, 1964 – 1975, over one million homes were built and it’s now time for an extensive modernization of these buildings.

    The purpose of this work was to see how the building envelope of a multifamily building from the Million Homes Programme can be energy efficient. This was done through enquiries and calculations, and by comparing these to current and future requirements of energy use. The enquiries that have been conducted were tests of impermeability and thermography. The calculations suggest both individual and combined actions to improve the building envelope.  The enquiries and calculations do not consider installations, architectural values, or economy, only how much the energy use can be optimized through improving the building envelope. 

    The best result achieved through combined actions was a reduction of energy use by 32,3 %. The individual action with the best result was the replacement of windows and balcony door: 16,4 % reduction of energy use.

    Only the building envelope has been taken in to account in this rapport which means that a greater improvement is possible if installations also is included.

    An important conclusion of the project is that the building envelope has a great effect on a building’s energy usage. The requirements of energy use that come into effect January 1, 2021 can be accomplished by only correcting the deficiencies in the building envelope.

  • 46.
    Andersson, Martin
    Dalarna University, School of Technology and Business Studies, Mechanical Engineering.
    Konceptutvärdering av gjutformshantering: Utformning och dimensionering av entresolplan enligt eurocode2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    ABB Components in Ludvika manufactures bushing for transformers. During the manufacturing, several steel molds are used. The molds are stored on a steel mezzanine floor constructed by several columns and beams. Due to that the amount of these molds has increased the existing way to handle and store these molds is impaired based on a safety and effectivity perspective. ABB have received two concept that propose how these problems could be solved. One is based on a solution with a special floor made of spheres. The other one is from a company called ELE Engineering AB that proposes a conveyor belt that is attached to the underside of the mezzanine floor. This will enable for 60 new molds to be stored. This work aims to evaluate how the mezzanine is affected by the weight of the new molds, how it should be strengthened and to evaluate which of the concept is recommended.

    Based on a series of simulations it is suggested that the mezzanine floor is reinforced with 21 new beams and 5 pillars to cope with the stresses the molds give rise to. The European standard EN-1090 has been the basis for how these columns and beams should be designed and attached. Further the two concepts will be evaluated based on effectivity, price and safety. Based on a concept evaluation ELEs solution is recommended despite lack of information about the floor with spheres.

  • 47.
    Andersson, Mikael
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Lind, Christoffer
    Dalarna University, School of Technology and Business Studies, Construction.
    Genomstansning i betong: En jämförelsestudie mellan Eurokod 2, Strusoft Winstatik Punching och Eurocode Software caeEc230.2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Computers have become invaluable for advanced calculation tasks in most industries.

    Formerly, designers had to rely on his skills and knowledge to perform calculations.

    Nowadays, designers can execute a calculation without the need to use the actual formulas

    behind. It is recommended by experienced designers that some of the programs used in the

    building industry, which are based on the European Eurocodes needs to be validated.

    The aim of this study has been to calculate the punching capacity of ordinary reinforced

    slab and to design the shear reinforcement, according to Eurocode 2. The method was a

    theoretical study of the Eurocodes. A calculation sheet for punching capacity was made in

    Mathcad. The calculations from the sheet were compared to Winstatik Punching and

    caeEc230. The work has been defined to include only an inner column on a concrete slab

    with a circular cross section without any column heads or other reinforcements. In order to

    achieve realistic calculations, nine cases with different slab thicknesses and spans were

    manipulated.

    The capacities from the three calculations were nearly identical, both at the columns

    perimeter and at the control perimeter. The greatest differences were found in the design of

    the shear reinforcement. They showed similar amount of reinforcement in terms of area, but

    offered no guidance on the design. CaeEc230 suggested about double the amount of rebar

    cuts than the calculations in Mathcad. Winstatik Punching reported no total at all.

  • 48.
    Andreason, Ellen
    Dalarna University, School of Technology and Business Studies, Construction.
    Grundvattenhantering i vägskärning: Överväganden, problem och bedömningar kring grundvattnet genom planerandet och byggandet2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Questions and problems related to groundwater management are important in road construction, especially at a cutting slope. The thesis describes the problems encountered during the construction of a road caused by high levels of groundwater. The aim of the thesis was to follow up considerations, problems and assessments considering groundwater connected to the building phase. Four specific aims were formulated; description of erosion control and of the assessments made considering groundwater and its effect on the construction, monitoring groundwater levels during the building phase and to do a simple theoretical calculation of the groundwater levels. 

    To meet the objective several methods were selected, literature review, surveys, interviews with people professionally related to the project and field measurements of groundwater tables.

    Measures to prevent erosion can be divided into vegetative and landscaped, either with soil and rock fills on the slopes or with various ditches. During the project, the design for the road and hillsides changed. Problems with groundwater and erosion have been important for the modified construction. Groundwater levels outside the intersection first increased, probably due to the deforestation and then dropped during the excavation. All but one pipe at the intersection show a lowering of the groundwater during the excavations and a smaller increase during snowmelt than in previous years. The calculated level of groundwater shows in one pipe a level far below the measured, indicating a continuing decrease, in the other pipe a higher level is calculated.

    Advanced vegetative erosion control systems are relative uncommon in Sweden today. Measurements of the groundwater tables should be carried out for a long time to provide a reliable reference level. Knowledge of the soils in the cutting intersection is important in the context of groundwater management together with a sufficient communication between those involved in the construction process. The groundwater levels in the intersection will probably continue its declining trend. Reliable calculations of groundwater tables are complex and their result can still be questioned.  

  • 49.
    Andrée Back, Johan
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Rolin, Tomas
    Dalarna University, School of Technology and Business Studies, Construction.
    Behovsstyrd ventilation: En fallstudie för zonstyrd ventilation i ett flerbostadshus2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The construction sector accounts for a large part of the primary energy use globally. In order to prevent global warming and to achieve the goals set by Sweden together with the EU, major changes are required in the sector. Energy requirements to heat and cool properties is an important part of this change and for people's well-being. The problem with many of today's system is that they are using more energy than needed and energy efficiency is a must to achieve the goals. Through innovative and smart systems, human needs can be safeguarded while energy requirements is reduced. The purpose was to investigate, through a case study, whether a new ventilation system for apartment buildings could make energy consumption more efficient while at the same time a high indoor comfort could be obtained. Only one apartment is considered which is located in Hedemora, Dalarna. The method was to install a demand-controlled ventilation system in the apartment and measure air quality, air temperature and air flow rate with the help of sensors The new ventilation system is then compared with two common ventilation strategies (extract air and natural ventilation).The energetic evaluation is based on measured air flow rates solely. The result was then compared to government recommendations regarding carbon dioxide levels. The measurement data shows that the demand-controlled ventilation system in most cases reaches the recommendations while the energy demand is lower. An important conclusion from the degree thesis is that ordinary ventilation strategies such as natural draft and exhaust air give a worse indoor climate compared to the demand-controlled system.

  • 50. Andrén, Lars
    et al.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Energy and Environmental Technology.
    Lennermo, Gunnar
    Handbok för kombinerade sol- och biovärmesystem: Teknik - System - Ekonomi2012Report (Other academic)
    Abstract [sv]

    Handboken beskriver olika solfångarkonstruktioner och solvärmekretsens ingående komponenter och ger en grundlig inblick i ackumulatortankens konstruktion och funktion. I boken finns förslag på systemutformning, olika tekniska lösningar och hur systemen bör styras och regleras. Handboken beskriver i första hand utformning-lösning-styrning av kombinationen sol- och pelletsvärme, men tar även upp solvärme i kombination med vedpannor, värmedrivna vitvaror och värmepumpar. Värmesystem med vattenburen värme är utmärkta att kombinera med solvärme, men det är i de flesta fall enklare att få till bra lösningar vid nyinstallation, än vid komplettering av befintlig anläggning. När solvärme och pelletsvärme ska kombineras finns det många alternativ till systemutformning. Det är viktigt att vattenburna pelletssystem utformas korrekt och kombineras på rätt sätt med solvärme för att komforten ska bli hög och elanvändningen låg. Vattenmantlade pelletskaminer med ett vattenburet värmesystem är extra intressant i kombination med solvärme. När eldningen upphör i samband med att värmebehovet avtar kan solvärmen ta över. En generell slutsats är att konventionella svenska pelletspannor med inbyggd varmvattenberedning inte är lämpliga i kombination med solvärmesystem. Den typen av bränslepannor ger komplicerade systemlösningar, höga värmeförluster och det är svårt att åstadkomma en tillräckligt bra temperaturskiktning i ackumulatortanken om varmvattenberedning sker i pannan. Solvärme för varmvattenberedning kan vara ett enkelt och bra komplement till pelletskaminer som genererar varmluft. För solvärmesystem är det viktigt att kraftig temperaturskiktning erhålls när värmelagret laddas ur. Det betyder att ackumulatortankens (eller varmvattenberedarens) nedre vattenvolym ska kylas ner till temperaturer som ligger nära ingående kallvattentemperatur. Ackumulatortankens mellersta del bör kylas till samma temperatur som radiatorreturen. Vid design av solfångarkretsen måste överhettning och stagnation kunna klaras utan risk för glykolnedbrytning eller andra skador på värmebärare eller rörkrets (och andra komponenter i kretsen). Partiell förångning minskar risken för att glykolen skadas då solfångaren når höga stagnationstemperaturer. Solfångarens glykolblandning tillåts koka (förångas) på ett kontrollerat sätt så att endast ånga blir kvar i solfångaren. Vätskevolymen i solfångaren samlas upp i ett större expansionskärl och systemet återfylls när vätskan kondenserar. Dränerande solfångarsystem med enbart vatten är ett möjligt alternativ till konventionella solfångare. De kräver en större noggrannhet vid installationen, så att sönderfrysning undviks. Dränerande systemlösningar är relativt ovanliga i Sverige. Om solfångaren under senhöst-vinter-tidig vår kan arbeta med att förvärma kallvatten från 10 till 20 ºC erhålls en betydligt bättre verkningsgrad på solfångaren (och framför allt ökar värmeutbytet då drifttimmarna ökar väsentligt) än om radiatorreturen (som i bästa fall ligger på temperaturnivån 30 - 40 ºC) ska förvärmas. Därför bör radiatorreturen placeras en bra bit upp från botten i ackumulatortanken och tappvarmvattnet ska förvärmas i en slinga som börjar i tankens botten. Om det finns ett VVC-system måste systemet anslutas på ett speciellt sätt så att ackumulatortankens temperaturskiktning inte störs. En viktig parameter vid ackumulatortankens utformning är att värmeförlusterna hålls låga. Det är viktigt för att klara tappvarmvattenlasten med solvärme under mulna perioder sommartid (men också för att hålla energianvändningen låg). I moderna hus, där ackumulatortanken i regel placeras i bostaden, blir det en komfortfråga att undvika övertemperaturer i det rum där värmelagret placeras. En bra standard på isoleringen (med minimerade värmeförluster) kräver att det finns ett lufttätt skikt över hela isoleringen som dessutom sluter tätt mot röranslutningar. Ofrivillig självcirkulation i anslutande kretsar som kan kyla av och blanda om ackumulatortankens vattenvolym, bör förhindras med backventiler och nedböjning av rören i isolerskiktet eller direkt utanför tanken.

1234567 1 - 50 of 1247
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