umu.sePublications
Change search
Refine search result
1 - 35 of 35
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • 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)
  • 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)
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.
    Andersson, Glenn
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Kommunikation mellan under- och byggentreprenör2015Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
    Abstract [en]

    The study about communication between subcontractor and design-and-build contractor are accomplished at Östervångskolan in Lund. The purpose with this study is to get a better understanding about how the communication works between the contractors today, find out which interferences and misunderstandings that influence the communication and which ways of communication that is being used at the working establishment. The building and development meetings are also being observed and analyzed at the working establishment. To examine how the contractors at Östervångskolan considered the communication today the method of qualitative interviews will be accomplished. These interviews generated a result, which was analyzed. The conclusion of this study is that the communication works fine but there’s a lot of deficits to rectify. One of the deficits that appeared was that the meeting protocol could be improved. A solution to this was to introduce a white board where the sub-contractors can write suggestions or thoughts. These will be processed by the supervisor and brought up at the weekly meeting to get a better participation in meetings. In the category “slutsats” more actions that will minimize the deficits in communication are described.

  • 2.
    Andersson, Sara
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Evaluation of the radiation protection at the new radiotherapy treatment department at the University Hospital of Umeå2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    At the University Hospital of Umeå, NUS, a new radiation treatment department is being built. The purpose of this master thesis is to evaluate the actual radiation protection outside three out of five treatment rooms in the building, including two Varian and one Siemens accelerator, and to verify that the radiation limits for the staff and the general public, stated by the Swedish Radiation Safety Authority, are obeyed.

    The evaluation of the radiation protection shielding is made through measurements. The nominal photon beam energies 6 and 15 MV (dose rates up to 500 MU/min) can be used, which means that both photons and neutrons will contribute to the effective dose. For the photon measurements, two different GM counters have been used and for the neutron measurements a Neutron detector with a polyethylene moderator and a 3He recoil proton counter tube was applied. The thesis also includes a literature study of the photon and neutron energy spectra outside the treatment rooms in order to check that the measurement equipments are suitable to use.

    The measured doses of the radiation shielding are below the radiation limits per week and year but the measurements indicate too high values per hour, i.e. momentary dose rate, at the height of isocenter of the primary walls and at the gap under the door for all three accelerators. The rooms with the Varian accelerators also show too high values per hour at the secondary wall where the door is attached. However, the limiting value per hour is only a recommendation and no extra reinforcement in therefore required. Nevertheless, one should avoid placing a workplace, for example a writing desk, close to the secondary and primary walls.

  • 3.
    Björ, Linn
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utredning av lämplig laddinfrastruktur för elbilar och laddhybrider i Umeå2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 4.
    Bränberg, Agneta
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Holmgren, Ulf
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Forskningsanknytning av grundutbildning: en praktisk analysmetod2015In: 5:e Utvecklingskonferensen för ingenjörsutbildningar: Proceedings, Uppsala: Uppsala universitet, 2015, 51-55 p.Conference paper (Other academic)
    Abstract [sv]

    Forskningsanknytning av grundutbildning kan och ska inte enbart vara fokuserad på att våra lärare är forskare. Det är så mycket mer kopplat till den. Som så många gånger när världen ser komplex ut är det lätt att man förenklar den alltför mycket. I denna artikel försöker vi vidga begreppen. Vi presenterar en analysmodell i form av ett fyrfältsdiagram, som kan byggas ut med en progressionsskala. Modellen som presenteras är ett verktyg som kan fungera både för analys av och som utgångspunkt för diskussioner om forskningsanknytning av ingenjörsutbildningar.

  • 5.
    Dahlberg, Joakim
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Eye Tracking with Eye Glasses2010Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study is concerned with the negative effects of wearing corrective lenses while using eye trackers, and the correction of those negative effects. The eye tracker technology studied is the video based real-time Pupil Center and Corneal Reflection method. With a user study, the wearing of eyeglasses is shown to cause 20 % greater errors in the accuracy of an eye tracker than when not wearing glasses. The error is shown to depend on where on the eye tracker viewing area the user is looking.

    A model for ray refraction when wearing glasses was developed. Measurements on distortions on the image of the eye caused by eyeglass lenses were carried out. The distortions were analyzed with eye tracking software to determine their impact on the image-to-world coordinates mapping. A typical dependence of 1 mm relative distance change on cornea to 9 degrees of visual field was found.

    The developed mathematical/physiological model for eyeglasses focuses on artifacts not possible to accommodate for with existing calibration methods, primarily varying combinations of viewing angles and head rotations. The main unknown in the presented model is the effective strength of the glasses. Automatic identification is discussed. The model presented here is general in nature and needs to be developed further in order to be a part of a specific application.

     

  • 6.
    Dzwilewski, Andrzej
    et al.
    Umeå University, Faculty of Science and Technology, Physics. Umeå University, Faculty of Science and Technology, Physics.
    Talyzin, Alexandr
    Umeå University, Faculty of Science and Technology, Physics. Umeå University, Faculty of Science and Technology, Physics. Experimental Physics.
    Bromiley, G.
    Dub, S.
    Dubrovinsky, Leonid
    Characterization of phases synthesized close to the boundary of C60 collapse at high temperature high pressure conditions2007In: Diamond and related materials, ISSN 0925-9635, Vol. 16, no 8, 1550-1556 p.Article in journal (Other (popular science, discussion, etc.))
    Abstract [en]

    Two sets of samples were synthesized at high pressure high temperature conditions in the P-T region where C-60 molecules collapse into a nearly amorphous graphite-like hard carbon phase. For the first set, heating temperature was varied at fixed pressure and preparation time. For the second set, synthesis time was varied at fixed pressure and fixed temperature. Detailed structural characterization of samples was performed using Raman spectroscopy and powder XRD. Mechanical properties of the samples have been studied by nanoindentation method. It has been found that duration of heat treatment under high pressure is an important parameter which influences the temperature of fullerene cage collapse. Both tetragonal and rhombohedral polymeric phases transform into hard carbon phase over a rather narrow temperature interval, but the tetragonal phase shows somewhat increased stability against C-60 collapse. Viscoelastic mechanical behavior during nanoindentation was observed for fullerene polymers but not for graphite-like hard carbon phase. Possible mechanism for nucleation of the hard carbon phase in polymeric C-60 networks is discussed.

  • 7.
    Engström, Philip
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Thermal CFD simulations of Scania engine test cell2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In engine development, measurements of thermal and mechanical engine perfor-mance is done in the so called engine test cell. In an ideal case, the engine test cell is designed to provide the same conditions as in a full truck installation. One of the most significant problems today is to understand the ventilation and the air dynamics in the test cell and how it affects the measurements. By the means of thermal CFD (Computational Fluid Dynamics) simulations we can understand the flow characteristics in a way that is impossible by simple measurements. The aim of this project is thus to understand the air flow dynamics, how heat is distributed in the engine test cell and its influence on the measurements, by the use of CFD. The procedure was to do measurements on the engine and use the results as boundary conditions on the engine as well as for validation of the simulation results. Temper-ature measurements on points of the surface for boundary conditions and points in the air for simulation validation. A transient simulation was then performed for a complex engine model in the CFD software PowerFLOW. The resulting simulation predicted the temperature at air points right after the engine fan within a relative error of 6% and less good at the turbo area, within 68%. This means that our simulation method predicted the temperature and thus the complex mixing of air after the fan well enough, but poorly at the back of the engine. This may be due to problems with the measurements but also radiation effects and gas leakages in the test cell, not considered in the simulation. A shield was put over the engine, to resemble the case when installed in a truck, that showed to increase the heat trans-fer coefficients, h, up to 366%. We conclude that the measurements in the test cell are highly affected by the complexity of the air flow. For future work the internal heat generation can be included in the simulation in order to predict the surface temperatures. It is also of importance to evaluate the effects of radiation and the extent of exhaust gas recirculation in the engine test cell.

  • 8.
    Ericson, Carl
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Kontroll och uppdatering av AB Vimmerbyhus byggsystem2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 9.
    Eriksson, Sara
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Quality by Design (QbD) in Biochemical Applications: Possibilities and Limitations2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 10.
    Fjällström, Ludvig
    et al.
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Vermelin, Leonard
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Kreditvärdighetsjusteringsmodell för ränteswappar2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Before the global financial crisis around 2008, the priority of the credit margin

    was comparatively low and was not taken into consideration as much as today.

    Many actors believed that credit risk could be neglected at various valuations.

    Due to that a lot of parties went bankrupt because of the low priorities. Today,

    this is a natural component in the financial market due to the capital regulation

    CRR and the Capital requirement directives (CRD IV), which are directly

    related to Basel III. In this thesis the authors have created a Credit valuation

    adjustment model, or a CVA-model, on behalf of the consulting firm AGL who

    want to use it in negotiations of interest rate swap with financial institutions.

    Factors as expected exposure, loss given default and probability of default are

    estimated in order to estimate a fair value for CVA. As a final product, the authors

    have created a model in VBA that can price CVA for individual contracts.

    This model is then evaluated and a sensitivity analysis is performed to see what

    impact credit rating and maturity have on the result.

  • 11.
    Granberg, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Clinical evaluation of atlas based segmentation for radiotherapy of prostate tumours2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Abstract

     

    Background

    Semi-automated segmentation using deformable registration of atlases consisting of pre-segmented patient images can facilitate the tedious task of delineating structures and organs in patients subjected to radiotherapy planning. However, a generic atlas based on a single patient may not function well enough due to the anatomical variation between patients. Fusion of segmentation proposals from multiple atlases has the potential to provide a better segmentation due to a more complete representation of the anatomical variation.

    Purpose

    The main goal of the present study was to investigate potential operator timesavings from use of atlas-based segmentation compared to manual segmentation of patients with prostate cancer. It was also anticipated that, and evaluated if, the use of semi-automated segmentation workflows would reduce the operator dependent variations in delineation.

    Materials and Methods

    A commercial atlas-based segmentation software (VelocityAI from Nucletron AB) was used with several atlases of consistently, protocol based, delineated CT images to create multiple-atlas segmentation proposals through deformable registration. The atlas that was considered most representative was selected to construct single generic atlas segmentation proposals. For fusion of the multiple-atlas segmentations an in-house developed algorithm, which includes information of local registration success was used in a MATLAB-environment[1]. The algorithm used weighted distance map calculations where weights represent probabilities of improving the segmentation results. Based on results from Sjöberg and Ahnesjö the probabilities were estimated using the cross correlation image similarity measure evaluated over a region within a certain distance from the segmentation.

    10 patients were included in the study. Each patient was delineated three times, (a) manually by the radiation oncologist, (b) with a generic single-atlas segmentation and (c) with a fusion of multiple-atlas segmentations. For the methods (b) and (c) the radiation oncologist corrected the proposed segmentations blindly without using the result from method (a) as reference. The total number of atlases used for case (c) was 15. The operator time spent by the radiation oncologist was recorded separately for each method. In addition a grading was used to score how helpful the segmentation proposals were for the delineations. The Dice Similarity Coefficient, the Hausdorff distance and the segmented volumes were used to evaluate the similarity between the delineated structures and organs.

    Results

    An average time reduction of 26% was found when the radiation oncologist corrected the multiple atlas-based segmentation proposals as compared to manual segmentations. Due to more accurate segmentations and more time saved, segmentation with fused multiple-atlases (c) was superior to the generic single-atlas (b) method, which showed a time reduction of 17%. Hints of an affected intra- and inter-operator variability were seen.

    Conclusions

    Atlas-based segmentation saves time for the radiation oncologist but the segmentation proposals always need editing to be approved for dose planning. The atlases, the fusion of these and the software implementation needs to be improved for optimal results and to extend the clinically usefulness.

  • 12.
    Grummas, Malin
    Umeå University, Faculty of Science and Technology, Umeå Institute of Design.
    Airborn: child safety in aviation2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The regulations of flying with infants are divided in two distinctly different fields. Either the infant have to ware a loop-belt attached to the parents lap belt. Or it is forbidden to use a lap belt and the infant is in this case unrestrained.

    None of these travelling methods are safe for the infant. The parent also has the option of using their own car seat if it is approved for airlines. This method is seldom used since the parent needs to pay for an extra seat for the infant and the hassle of bringing a seat on board that rearly fit the eairline seat.

    This project proposes a solution that increases the comfort and safety for both parent and child by; placing the infant in a safer position, protect the infant from impact with low-tech aircushions, securing the infants head at impact and during emergency evacuations and by providing a safe and easy to use alternative to the lifejacket.

    The final concept allows for tree different areas of use: 

    -On the bulkhead wall, the seat is lowered in the unlikely event of an emergency to clear the adults crash zone and protect the infant from the adult and flying objects.

    -In the lap of the adult passenger, resting on the armrest (in this case the infant and the seat is attached to the adults belt). The lifejacket is inflated before impact and acts as an impact distributor over the infant’s body. This allows for more seats since the bulkhead seats are very limited. 

    -Placed on its own passenger seat (the parents will have to purchase an extra seat) and be working as the care harness but suitable for infants.

    These tree solutions covers most users different needs and is an improvement of the safety for small children in commercial aircrafts.

  • 13.
    Hellström, Thomas
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    A random walk through the stock market1998Other (Other academic)
  • 14.
    Hållbus, Richard
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Undersökning om värmeförluster från kabninen kan användas som avisningsmetod2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 15.
    Iwasiewicz-Wabnig, Agnieszka
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Studies of carbon nanomaterials based on fullerenes and carbon nanotubes2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Materials based on fullerenes and carbon nanotubes are very much different from most “traditional” materials, primarily because they are built from nanosized molecules with highly symmetry-dependent properties. Being the subject of a very active research field over the last twenty years, carbon nanostructures proved to be indeed extraordinary. Their splendid mechanical properties attract a great interest among material scientists. Their wide range of electrical properties, from ballistic conductors to insulators, makes them ideal candidates for future, better electronics. The possibilities seem to be nearly unlimited, with proposed applications ranging from quantum computing to medicine. However, in order to make it all happen one day, we first need to explore and understand the physics and chemistry of carbon nanomaterials. This work focuses on production and characterization of materials and structures in which fullerenes and/or carbon nanotubes are the main ingredients, and which can be produced or modified under high-pressure – high-temperature (hp-hT) conditions. Raman and photoluminescence spectroscopy, X-ray diffraction and scanning probe microscopy were employed for characterization of the samples. The research presented in this thesis is spread over a rather wide range of carbon nanomaterials. To highlight some of the main results – the first hp-hT polymerization of C60 nanorods and the C60-cubane compound is reported. The polymerization mechanism in the latter case was identified to be radically different from that in pure C60. The pressure-temperature diagram of C60-cubane is presented. A comparative study of C60 and C70 peapods under extreme p-T conditions reveals how the confinement affects the fullerenes’ ability for polymerization. Finally, in situ resistance measurements on Rb4C60 under high pressure show that the semiconducting character of this material persists at least up to 2 GPa, contradicting earlier reports on the existence of an insulator-to-metal transition and providing an insight into conduction mechanisms in this anomalous intercalated compound.

  • 16. Jönsson, Leif
    et al.
    Alriksson, Björn
    Soudham, Venkata Prabhakar
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Methods for improvement of enzymatic hydrolysis of lignocellulosic material2013Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    The present invention relates to a method of enzymatic hydrolysis of a lignocellulosic material, comprising the steps of: a) pretreating the lignocellulosic material to obtain a slurry having a pH of less than 6; b) adding NaOH, Ca(OH)2 and/or CaO to the slurry to increase its pH to at least 8, said addition being carried out at a slurry temperature of at least 60 °C; c) reducing the pH of the slurry to below 7; and optionally cooling the slurry from step b) to a temperature below 60 °C; and d) adding hydrolytic enzymes to the slurry from c) and allowing the slurry to hydrolyze wherein no washing of the slurry is performed prior to step d)

  • 17.
    Lundmark, Martin
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Clinical evaluation of atlas-based segmentation for radiotherapy of head and neck tumours2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Background

    Semi-automated segmentation using deformable registration of atlases consisting of pre-segmented patient images can facilitate the tedious task of delineating structures and organs in patients subjected to radiotherapy planning. However, a generic atlas based on a single patient may not function well enough due to the anatomical variation between patients. Fusion of segmentation proposals from multiple atlases has the potential to provide a better segmentation due to a more complete representation of the anatomical variation.

    Purpose

    The main goal of the study was to investigate potential operator timesaving from editing of atlas-based segmentation compared to manual segmentation for head & neck cancer.

    Materials and Methods

    A commercial atlas-based segmentation software (VelocityAI from Nucletron AB) was used together with several expert generated and protocol-based atlases of delineated CT images to create multiple atlas segmentations through deformable registration. The atlas that was considered most universal was selected to construct single atlas segmentation proposals. For fusion of the multiple atlas segmentations an in-house developed algorithm, including information of local registration success was used in a MATLAB-environment1. The algorithm uses weighted distance map calculations where weights represent probabilities of improving the segmentation results. Based on previous results1 the probabilities were estimated using the cross correlation image similarity measure evaluated over a region within a certain distance from the segmentation. Ten patients were incorporated in the study. Each patient was delineated three times, (a) manually by the radiation oncologist, (b) with a single atlas segmentation and (c) with a fusion of multiple atlas segmentations. For the methods (b) and (c) the radiation oncologist corrected the proposed segmentations blindly without using the result from method (a) as reference. For case (c) a total number of 11 atlas segmentations were used. The time spent for segmenting or editing the segmentation proposals by the radiation oncologist was recorded separately for each method and each individual ROI. In addition a grading was used to score how helpful the candidate segmentation proposals were for the structure delineations. The Dice Similarity Coefficient, the Hausdorff distance and the volume were used to evaluate the similarity between the delineated structures.

    Results

    The results show a time reduction in the order of 40% when the radiation oncologist only has to correct the multiple atlas-based segmentation proposal compared to manual segmentation. When using single atlas the corresponding figure is 21%.

    Conclusions

    Using atlas-based segmentation can reduce the time needed for delineation in the head and neck area of patients admitted for radiotherapy.

    1C. Sjöberg and A. Ahnesjö, Evaluation of atlas-based segmentation using probabilistic weighted distance maps, Manuscript, Uppsala University, 2011

  • 18.
    Maxe, Anneli
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Att genomföra ett projekt2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report is based on the thesis for the Degree in Media Technology at Umeå University. The thesis work has been done with Heja! Event and Sponsorship agency on behalf of Olofsfors-AB.

    The report describes how a project is implemented, both theoretically and practically through a completed project for Heja!'s client, Olofsfors AB and through Swedish and English literature. The report aims to show how a project's implementation differs from the actual theories available.

    Since there is no opportunity for in-depth information about the project carried out by the completed portions, a theoretical framework has been developed. The theoretical framework deals with a general project model approach and a project organization structure. The general project model has been described step by step while the specification of roles and their responsibilities in the organization structure is established.

    Olofsfors AB is described from the past, present and future. The implementation section describes how the project has been completed from start to finish using the Heja! project model.

    Using the theoretical framework, the finished project and personal opinions, a conclusion and discussion designed to answer the questions that are the basis for the report was produced. The conclusion describes what a project model means, and if Olofsfors AB has managed to achieve the purpose and the goal of the project. Proposals for further work and discussion about personal aspects are described.

  • 19.
    Moström, Annika
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lagarbete och muntlig kommunikation för Högskoleingenjörsutbildning i byggteknik2013Conference paper (Other academic)
    Abstract [sv]

    På Högskoleingenjörsprogrammet i byggteknik vid Umeå universitet har vi infört ett samarbete mellan första och sista årskursen där studenterna får träning i lagarbete och kommunikation. Studenterna på årskurs tre planerar och genomför ett studiebesök på en byggarbetsplats för årskurs ett. I uppgiften ingår även att ansvara för slutredovisning av studiebesöken. Uppgiften avslutas med en skriftlig självvärdering av genomförandet studiebesöken. För nybörjarna är det intressant att lära känna de nästan färdiga ingenjörerna samtidigt som de får en första kontakt med byggbranschen. Den största behållningen för de som går sista året är insikten om hur mycket byggteknik de faktiskt lärt sig de senaste två åren. Samverkan mellan två kurser på utbildningsprogrammet ger möjlighet att praktiskt arbeta med lagarbete och muntlig kommunikation. Båda grupperna tränar språkliga färdigheter i byggteknik utifrån sin nivå.

  • 20.
    Mårtensson, Oskar
    Umeå University, Faculty of Science and Technology, Department of Physics.
    LHCb Upstream Tracker box: Thermal studies and conceptual design2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The LHC (Large Hadron Collider) will have a long shut down in the years of 2019 and 2020, referred to as LS2. During this stop the LHC injector complex will be upgraded to increase the luminosities, which will be the first step of the high luminosity LHC program (which will be realized during LS3 that takes place in 2024-2026). The LHCb experiment, whose main purpose is to study the CP-violation, will during this long stop be upgraded in order to withstand a higher radiation dose, and to be able to read out the detector at a rate of 40MHz,compared to 1MHz at present. This change will improve the trigger efficiency significantly. One of the LHCb sub-detectors the Trigger Tracker (TT), will be replaced by a new sub-detector called UT. This report presents the early stage design (preparation for mock-up building) of the box that will be isolating the new UT detector from the surroundings and to ensure optimal detector operation. Methods to fulfill requirements such as light and gas tightness, Faraday-cage behavior and condensation free temperatures, without breaking the fragile beryllium beam pipe, are established.

  • 21.
    Nordlund, Andreas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Förspända betongelement: Dimensionering enligt Eurokod 22013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The objective of this thesis is to understand the theory and learn the calculation behind prestressed concrete elements and to compare it with the theory of ordinary reinforced concrete elements. This thesis work was chosen in order to promote the study of prestressed concrete and because it´s broad application in civil engineering. The worked was completed by reading literature and guidance.

    It turned out after the work was completed that some parts of the theory and calculation behind prestressed concrete was similar to that used in the ordinary reinforced concrete. However, there were also many differences that existed. Some of the similarities are obtained when the capacities of moment and shear are calculated. The differences is that many extra steps are required when the design are performed, steps who for the most part due to different controls and are required to be performed to ensure the safety of the design. The controls are to be performed, among other, in the design of the manufacturing process and in the ultimate limit state.

    Finally, it is found that prestressed concrete elements have many benefits, which includes larger spans, smaller dimensions for structures and that smaller deformations can be obtained. However, it will require a larger amount of calculations as compared to ordinary reinforced concrete.

  • 22.
    Nyström, Robin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nordin, EZ
    Blomberg, Anders
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Sandström, Thomas
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    A novel set-up for source characterization and human exposures of biomass combustion aerosols2013Conference paper (Other academic)
  • 23.
    Nyström, Robin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Sadiktsis, Ioannis
    ept. of Analytical Chemistry, Arrhenius Laboratory, Stockholm University.
    Trifa, Mohammad Ahmed
    Dept. of Analytical Chemistry, Arrhenius Laboratory, Stockholm University.
    Roger, Westerholm
    ept. of Analytical Chemistry, Arrhenius Laboratory, Stockholm University.
    Koegler, Jan
    Volvo Group Trucks Technology, ATR, Gothenburg, Sweden.
    Mudway, Ian S
    4MRC-PHE Centre for Environment and Health, School of Biomedical Sciences, King’s College London, UK.
    Blomberg, Anders
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Sandström, Thomas
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Properties of biodiesel exhaust particles from two non-road engines2014Conference paper (Other academic)
  • 24.
    Oja, Sofie
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    En studie av möjliga energieffektiviseringar i ett äldre flerbostadshus: Simuleringar genomförda i IDA ICE 4.6.22016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Energy efficiency could be described as ”using less energy to provide the same service”.  There are many motivations to improve energy efficiency in buildings, for example financial cost savings to consumers and at the same time a reduction of the environmental and climate impact.

    In my thesis, I have on behalf of the real estate ”Skelleftebostäder” investigated one of their multi-residential properties to study possible energy efficiency improvements, such as replacement of the ventilation system, new windows and insulation of the attic floor. Life cycle cost analyzes have also been calculated to analyze how much each action will cost based on its lifetime, compared to if no action would be done.

    The work has mainly been conducted through literature studies with the use of the simulation program IDA ICE, where a model of the property has been constructed according to current conditions and energy needs. Subsequently, the simulations carried out for each energy efficiency act have then been compared with a reference house.

    The results showed that all the investigated energy efficiency acts would reduce the property´s energy use mainly by changing the ventilation system (which would reduce the property's energy performance by up to 35 %). Minimum savings of energy would additional insulation of the attic floor give; It would only reduce the energy performance by 4%. Of all the investigated energy efficiency acts and with regard to their life-length, it is however only new windows which turned out to be economical profitable for this building.

  • 25.
    Olofsson, Erik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Jakobsson, Jonny
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Control System for Electromagnetic Environmental Testing of Electronics with Reverberation Chamber2009Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    A reverberation chamber is a highly conductive cavity in which it is possible to generatehigh electromagnetic elds that can be considered statistically homogeneous. Reverberationchambers have existed as a resource for electromagnetic compatibility (EMC) testing formore than 30 years. Working to promote international co-operation on standardization, severalorganizations have published various EMC standards. At Combitech AB in Linkopinghave a chamber that is commercially used for dierent types of measurements. To makethe chamber more attractive and versatile it is within their interest to get a system whichis compatible with the latest standards. The project aimed to develop a control system forthe reverberation chamber at Combitech and to equip it with functionality enabling it tomake measurements according to current EMC standards. Using the programming softwareAgilent VEE a program was developed to communicate with the supporting equipment andmanage test routines. Within the program software lies functionality directly associate withmode stirring and mode tuning procedures for standards DO-160F and MIL-STD. Duringmeasurements the program has abilities for skipping frequencies, pause/continue the currentsweep, executing preset events and adding commented markers to the plot window. Someother usable functionality implemented is project save/load, help section, directory selectionand data export abilities. The system holds functionality enabling measurements accordingto the standards in question, though future work will be needed to be able to carry througha proper and correct measurement routine.

  • 26.
    Rawcliffe, Denise
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Muscle Specific Aberrant Splicing of Mutated ISCU in Hereditary Myopathy with Lactic Acidosis2013Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
  • 27.
    Sandström, Anders
    Umeå University, Faculty of Science and Technology, Umeå Institute of Design.
    IMPROVING SELF-RESCUE EQUIPMENT: Can a self-contained self-rescue unit be more comfortable to wear over long periods of time, not damage other equipment and be donned easily?2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A self-contained self-rescue unit is a device that is used in the mining industry in case of fires or release of toxic gases that depletes or contaminates breathable oxygen in the surrounding atmosphere. These units are the first line of defense by providing oxygen in a closed breathing cycle, allowing personnel to get themselves to safety.

    The goal of this project was to design a unit that is more comfortable to carry during the daily operations in and outside the mines. A unit that is easier to done and less likely to damage the users and/or surrounding mining equipment. It is developed in close collaboration with Atlas Copco, as the main sponsor, as well as Dräger and personnel working at Zink Gruvan Mining. 

    The result is a unit with an operational time of twenty minutes and a reduced size and weight. It’s position can be adjusted to be worn around the waist or the chest, depending on the tasks the user performs, as well as simplifying the donning procedure.

  • 28.
    Sjöström, Cecilia
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Manual till introduktionsfilm2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna rapport handlar om hur utbildningsfilmer skapas. Syftet med rapporten är att förklara hur arbetet gjorts med att skapa utbildningsfilmer. Hur det går till, steg för steg, när en utbildningsfilm skapas och vad som är viktigt att tänka på när man till exempel filmar eller redigerar. Det kommer att finnas bilder med förklarade text så att det ska vara lätt att förstå samt få en inblick om hur det kan se ut. En utbildningsfilm kan exempelvis följa en föreläsning eller beskriva en operation och den används till att utbilda studenter. Den blir ett utbildningsmaterial som kan användas via en klassmiljö men även för distansstuderande.  Det färdiga resultatet läggs sedan upp på en hemsida där elever kan gå in och titta på det.

  • 29.
    Soudham, Venkata Prabhakar
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Raut, Dilip Govind
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Anugwoma, Ikenna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Brandberg, Tomas
    Larsson, Christer
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Coupled Enzymatic Hydrolysis and Ethanol Fermentation: Ionic Liquid Pretreatment for Enhanced Yields2015In: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 8, 135Article in journal (Refereed)
    Abstract [en]

    Background

    Pretreatment is a vital step upon biochemical conversion of lignocellulose materials into biofuels. An acid catalyzed thermochemical treatment is the most commonly employed method for this purpose. Alternatively, ionic liquids (ILs), a class of neoteric solvents, provide unique opportunities as solvents for the pretreatment of a wide range of lignocellulose materials. In the present study, four ionic liquid solvents (ILs), two switchable ILs (SILs) DBU–MEA–SO 2 and DBU–MEA–CO 2 , as well as two ‘classical’ ILs [Amim][HCO 2 ] and [AMMorp][OAc], were applied in the pretreatment of five different lignocellulosic materials: Spruce (Picea abies) wood, Pine (Pinus sylvestris) stem wood, Birch (Betula pendula) wood, Reed canary grass (RCG, Phalaris arundinacea), and Pine bark. Pure cellulosic substrate, Avicel, was also included in the study. The investigations were carried out in comparison to acid pretreatments. The efficiency of different pretreatments was then evaluated in terms of sugar release and ethanol fermentation.

    Results

    Excellent glucan-to-glucose conversion levels (between 75 and 97 %, depending on the biomass and pretreatment process applied) were obtained after the enzymatic hydrolysis of IL-treated substrates. This corresponded between 13 and 77 % for the combined acid treatment and enzymatic hydrolysis. With the exception of 77 % for pine bark, the glucan conversions for the non-treated lignocelluloses were much lower. Upon enzymatic hydrolysis of IL-treated lignocelluloses, a maximum of 92 % hemicelluloses were also released. As expected, the ethanol production upon fermentation of hydrolysates reflected their sugar concentrations, respectively.

    Conclusions

    Utilization of various ILs as pretreatment solvents for different lignocelluloses was explored. SIL DBU–MEA–SO 2 was found to be superior solvent for the pretreatment of lignocelluloses, especially in case of softwood substrates (i.e., spruce and pine). In case of birch and RCG, the hydrolysis efficiency of the SIL DBU–MEA–CO 2 was similar or even better than that of DBU–MEA–SO 2 . Further, the IL [AMMorp][OAc] was found as comparably efficient as DBU–MEA–CO 2. Pine bark was highly amorphous and none of the pretreatments applied resulted in clear benefits to improve the product yields.

  • 30.
    Teglund, Daniel
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Heartbleed: Vad är det och hur drabbas man?2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    On April 7, 2014, the news about Heartbleed was released to the public. The news told us about a serious security flaw found in OpenSSL, a widely used implementation of the SSL/TLS protocols used to encrypt a large part of online communication. The security bug meant that anyone with the right knowledge could steal up to 64 kB of information from a vulnerable server’s internal RAM memory, without leaving behind any trace.

    The study includes a description of what Heartbleed is, how SSL/TLS works and what SSL-certificates are. It describes how an SSL-handshake is used to create an encrypted session between a client and a host and how an attack against a vulnerable server works. The study also includes short interviews with companies that were using the affected versions of OpenSSL and a survey of how they handled this incident.

    The purpose of this study is to gain an understanding as to how the Heartbleed bug works and what businesses and individuals using the internet at home can do to avoid being affected.

    Because this security flaw has affected a large number of companies and thus risked the privacy of their customers, it is my hope that this study will help provide a thorough but easily understandable insight into what Heartbleed is

  • 31.
    Törmänen, Patrik
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Forecasting important disease spreaders from temporal contact data2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 32.
    Törnqvist, Joacim
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Non-contact High Voltage Measurements: Modeling and On-site Evaluation2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the high voltage grid, voltage measurements are made in dedicated voltage-transformers. These devices are expensive and insulation failures could impact directly on the system, and even cause a power outage. A non-contact measurement technique, on the other hand, does not require a connection to the conductors, and the sensors can therefore be much cheaper by avoiding the need for high voltage insulation.

    A capacitive coupling between three measurement electrodes, close to ground, and a high voltage three phase conductor system is used to model and measure the electric field and thereby determine the potentials of the conductors. A 2D-model is used for simulations, where the sensors are modeled as ideal, the conductors are modeled in an infinite wire approximation, and the ground plane is approximated as a perfect conductor. For non-ideal sensors a transfer function from the potentials on the measurement equipment to the potentials on the conductors is derived as a lumped-circuit model.

    The L2-norm errors for the amplitude and the phase in the reconstructed signals are calculated and measured for various sensor distances. Simulations show that the sensor distance should not be larger than the conductor distance to mitigate the erroneous effects from distance uncertainties. The optimal sensor distance depends on the quota between the height from the sensors to the conductors and the conductor distance.

    Measurements show, in accordance with the theory, that the sensor distance should not be larger than the conductor distance. To reduce the amplitude and phase shift errors the sensors should be placed close to the ground. For applied load resistances there is a tradeoff between amplitude- and phase shift errors. Additionally, higher load resistances attenuate higher frequencies. Measurements have verified that this technique is capable of detecting high harmonics and transients.

    The relatively low cost and the movability makes this method highly applicable for quick diagnostics on many locations in a grid, where the data can be evaluated on-site using computer based scripts.

  • 33.
    Yang, Bin
    et al.
    Berkeley Education Alliance for Research in Singapore, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore.
    Schiavon, Stefano
    University of California, Berkeley.
    Sekhar, Chandra
    National University of Singapore.
    Cheong, David
    National University of Singapore.
    Tham, Kwok Wai
    National University of Singapore.
    Nazaroff, William W
    University of California, Berkeley.
    Cooling efficiency of a brushless direct current stand fan2015In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 85, 196-204 p.Article in journal (Refereed)
    Abstract [en]

    The idea of far transfer effects in the cognitive sciences has received much attention in recent years. One domain where far transfer effects have frequently been reported is music education, with the prevailing idea that music practice entails an increase in cognitive ability (IQ). While cross-sectional studies consistently find significant associations between music practice and IQ, randomized controlled trials, however, report mixed results. An alternative to the hypothesis of cognitive transfer effects is that some underlying factors, such as shared genes, influence practice behaviour and IQ causing associations on the phenotypic level. Here we explored the hypothesis of far transfer within the framework of music practice. A co-twin control design combined with classical twin-modelling based on a sample of more than 10,500 twins was used to explore causal associations between music practice and IQ as well as underlying genetic and environmental influences. As expected, phenotypic associations were moderate (r = 0.11 and r = 0.10 for males and females, respectively). However, the relationship disappeared when controlling for genetic and shared environmental influences using the co-twin control method, indicating that a highly practiced twin did not have higher IQ than the untrained co-twin. In line with that finding, the relationship between practice and IQ was mostly due to shared genetic influences. Findings strongly suggest that associations between music practice and IQ in the general population are non-causal in nature. The implications of the present findings for research on plasticity, modularity, and transfer are discussed.

  • 34.
    Zhang, Huichun
    et al.
    College of Mechanical and Electronic Engineering, Nanjing Forestry University, Nanjing 210037, China.
    Dorr, Gary
    Faculty of Science, The University of Queensland, Brisbane 4343, Australia.
    Zhang, Jiaqiang
    College of Mechanical and Electronic Engineering, Nanjing Forestry University, Nanjing 210037, China.
    Zhou, Hongping
    College of Mechanical and Electronic Engineering, Nanjing Forestry University, Nanjing 210037, China.
    Yu, Jun
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Wind tunnel experiment and regression model for spray drift2015In: Transactions of the Chinese Society of Agricultural Engineering, ISSN 1002-6819, Vol. 31, no 3, 94-100 p.Article in journal (Refereed)
    Abstract [en]

    With greater environmental awareness, the movement of pesticides within and off of a spray target area is acritical public concern. Ideally, all of the material applied should be deposited within the targeted swath on the intendedpest or plant. But realistically, a portion of the spray remains airborne and is carried downwind to non-target areas.Airborne spray leaving the targeted area reduces the applied dosage, and could cause damage to neighboring plant andwater source or other detrimental environmental impacts. To study the influences of nozzle type, spray mixture and windspeed on spray drift, experiments were conducted using a wind tunnel. Spray drift risk was assessed by adding a tracer tothe spray mixture and measuring the quantities of spray deposited downwind from the nozzle on horizontal polythenelines with 2 mm diameter perpendicular to the wind direction in a vertical and a horizontal array. At a distance of 2 mdownwind from the static nozzle, five collector lines (V1 to V5) were positioned one above the other at the spacing of0.1 m to provide an estimate of the spray still airborne through this vertical profile. An additional five sampling collectorstrings (H1 to H5) were placed in a horizontal array with one-meter horizontal spacing at 0.1 m height to determine thefallout volumes and gradients of the spray from 2 to 6 m downwind. A water-soluble fluorescent tracer was dissolvedinto tap water as the spray liquid, and after the experiments, the collecting lines were washed with deionized water tomeasure deposit and drift. The results indicated that deposits on sampling collector decreased with increased verticalelevation and horizontal distance. Average fallout and airborne deposit resulting from the different spray applicationswere shown in the paper. These figures showed the expected fallout and airborne profiles for all tested nozzle types andsizes. The highest fallout deposits were measured at a position closest to the nozzle (H1) with a systematic decrease withthe distance from the nozzle. The highest airborne deposits were found at the lowest sampling collector (V1) with asystematic decrease with increasing height above the wind tunnel floor. Airborne spray drift was affected by wind speed.At all sample positions, deposits on collectors were reduced at lower wind speed. Nozzle’s structure was also found toinfluence droplet’s size, so injector/pre-orifice nozzle produced coarser droplets and reduced spray drift. The amount ofspray recovered is based on the amount of active ingredient of spray mixture within each droplet rather than the totaldroplet volume. On that basis, a multiple non-linear model for statistical drift prediction including four independent,non-correlated variables (target distance, wind speed, nozzle type and chemical type) was established. The regressionmodel provided a drift evaluation approach, and it was important in the interpretation of wind tunnel data for differentnozzle types, chemical types and sampling methodologies.

  • 35.
    Åstrand, Max
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Ventilation Performance Monitoring in Underground Mines2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Ventilation of underground mines is a critical, complex and expensive activity. Removing pollutants from e.g. diesel equipment is important to insure a safe and operable work environment in the mine. The energy consumption of ventilation for an underground mine typically comprises around 30-50% of the total energy consumption of underground mine operation. It is therefore vital that the performance of the ventilation system can be monitored and maintained as high as possible. The goal of this project is to develop methods  and algorithms which are useful in this context. The developed methods and algorithms are tested in two real mine case studies.

1 - 35 of 35
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • 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