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  • 201.
    Bjarnhagen, Rikard
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Service Enhancer Tool: Design of a new Service Enhance Tool for Metso refiners2013Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Metso develops (among many other things) refiners. The refiner grinds the wood chips intopulp. The grinding is done by segments that are placed on a rotor inside the refiner hosing.In time this segments wear and needs to be replaced.When changing refiner segments or performing service to the refiner the rotor needs to berotated. To perform the rotating motion today the overhead crane is used. This procedure isboth impractical, dangerous and takes precious time from the overhead crane. Because ofthis Metso wanted to create a new way to rotate the rotor.The aim of this thesis is to create a tool or equipment which can be used to rotate therefiner rotor and can be installed as an upgrade on all Metso refiner models.The proposed design is driven with a 1.1 kW electrical motor and a gearbox with a gear ratioof approximately 1:217. The torque is transferred from the outgoing gearbox shaft to therefiner shaft with the help of gearwheels. To connect the gearbox gearwheel with the refinershaft gearwheel, the gear motor has to be moveable in a radial direction. This is done by themeans of two shafts that glides in four bushings. On the gearbox shaft a gearwheel with 120mm of face width is mounted. The large face width is used to take up the axial movement ofthe refiner shaft.The proposed concept fulfills all of the demands set in the pilot study. The design is goodbecause of the low cost and straight forward design that is easy to build and simple to use.The disadvantage is that the equipment is a bit large and heavy, but as stationary equipmentthis should not be a problem.

  • 202.
    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
  • 203.
    Björk, Alexander
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Control of Multibody Machines using Rate Gyros and Optronics2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project deals with design and prototype testing of a reversing car trailer systemequipped with a rate gyro and optronics to locate a target and drive to it. Simulink isused for developing and implementing the control system, it was also used to remotelyoperate the vehicle with a Man-in-the-Loop input. Given a starting position the user cancontrol a servo holding a laser range finder and a laser pointer to find a suitable target,and then lock the vehicle on it to later make it autonomously approach it.

    The finished car trailer system can, when driving straight backwards, reach the destinationwithin the vicinity of 10 ± 7 cm from a starting position 3 m away. When reversingto a target with an angular offset the accuracy and precision is decreasing.

    Provided the short time frame for a project that covers both designing, building andtesting of the final product the robot was experimentally tested only a few times. Moretesting is necessary to show limitations in design and implementation.

    The combination of experimental results and simulations this project has resulted inshows a proof of concept for this type of autonomous vehicle, although further improvementsand tests are vital to improve performance and reliability.

  • 204.
    Björk, Alexander
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Control of Multibody Machines usingRate Gyros and Optronics2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project deals with design and prototype testing of a reversing car trailer systemequipped with a rate gyro and optronics to locate a target and drive to it. Simulink isused for developing and implementing the control system, it was also used to remotelyoperate the vehicle with a Man-in-the-Loop input. Given a starting position the user cancontrol a servo holding a laser range finder and a laser pointer to find a suitable target,and then lock the vehicle on it to later make it autonomously approach it.

    The finished car trailer system can, when driving straight backwards, reach the destinationwithin the vicinity of 10 ± 7 cm from a starting position 3 m away. When reversingto a target with an angular offset the accuracy and precision is decreasing.

    Provided the short time frame for a project that covers both designing, building andtesting of the final product the robot was experimentally tested only a few times. Moretesting is necessary to show limitations in design and implementation.

    The combination of experimental results and simulations this project has resulted inshows a proof of concept for this type of autonomous vehicle, although further improvementsand tests are vital to improve performance and reliability.

  • 205.
    Björklund, Johannes
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Projektering av träbroar: En undersökning av förbättringsåtgärder för anpassning av Tekla Structures mot träbroprojektering2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this project has been to study which requirements apply on wooden bridges from a design perspective, observing both external requirements and internal requirements from the company Martinsons. Based on these requirements measures would be proposed to adapt Martinsons Tekla-template model for the design of timber bridges. The theoretical part of the project has, as a starting point been conducted by studies of the Transport Administration's requirements on wooden bridges. Discussions with designers working with wooden bridges have also been conducted to get an understanding of their experiences and opinions. Furthermore, a number of previously constructed wooden bridges have been studied in order to find areas in need of improvement. With this background, it then examined which measures were feasible in Tekla. Several measures that would aim to improve the drawing quality and comply with the applicable requirements was produced and declared in the project. Measures aimed to streamline the modeling and drawing creation was also proposed. The measures proposed should enhance Martinsons Tekla-template model in a significant way, but shall in no way be considered as a definitive solution in the quest to meet the requirements concerning the design of wooden bridges. The projekct made it clear that it is not reasonable, or even feasible, to adjust the template model to meet all requirements, some adjustments must be done in each project. It also became clear that it would be good to open a dialogue with the Swedish Transport Administration to make sure what their requirements are so that Martinsons can comply with them in an effective way.

  • 206.
    Björklund, Jonathan Björklund
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    En kartläggning av producentens roll i skapandet av en kortfilm.: A survey of the producer’s role in the making of a short film.2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    En kortfilm definieras främst av dess längd på max 30 minuter, men även av att kortfilmsprojekt ofta utförs med en synnerligen liten budget samt att konstnärlig ambition värderas högre än kommersiell nytta. Att producera en självständig kortfilm är arbetsamt och sällan speciellt lukrativt, men att driva ett självständig kortfilmsprojekt, följa och fullgör sin egna vision, genererar erfarenheter som kan leda till fantastiska möjligheter. Tydligt är att producentrollen utgör en viktig del i ett kortfilmskapande, desto otydligare är vad rollen exakt består i. Den här studien har som syfte att kartlägga producentens roll och arbetsuppgifter vid skapandet av en självständig kortfilm.

     

    Parallellt med framställandet av rapporten utfördes ett kortfilmsprojekt av rapportens författare tillsammans med två kurskamrater. Målet med kortfilmsprojektet var att genom utförandet av de nödvändiga momenten i ett kortfilmsskapande erhålla viktiga och värdefulla erfarenheter inför framtida kreerande. För att förvärva ytterligare kunskap specifikt gällande producentens roll genomfördes en litteratursökning i ämnet. Denna litteratursökning kom att visa på bristen av tillgänglig information i ämnet vilket mynnade ut i rapportens frågeställning. 

  • 207.
    Björklund, Lina
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utvärdering av byte till energieffektiv belysning i tryckeri2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The result of an energy survey at the printing company VK – Media showed that the energy use of the old lighting was a large part of the total energy use. The old lighting with high-pressure sodium luminaires and high-pressure sodium light sources was then replaced with a new energy-efficient lighting with two different LED luminaires in the packaging room at the printing company. An evaluation of the replacement of the luminaires should now be carried out. The evaluation of the lighting change is based on the reduction of energy use, differences of illuminance and changes in the working environment.

     

    The primary aim of the lighting replacement is to reduce the energy use and to improve the working environment. Simulations on the lighting with high-pressure sodium light sources and LED luminaires have been made in DIALux evo. In DIALux, calculations were made on illuminance and energy use. Momentary power measurements with a multimeter have been carried out on the lighting before and after the replacement. The measured power was then used to calculate the annual energy use for the luminaires. The illuminance were measured with a luxmeter in the packing room and the measured values was then used to calculate the average illuminance and the uniformity of the lighting, to see if they stand against the guideline values and compare them with the values from DIALux. The life cycle cost was calculated for the lighting with high pressure sodium light sources and for the lighting with LED luminaires. The payback time was also calculated for the new lighting with LED luminaires.

     

    The result of the calculations on the energy use showed that the annual energy use will be reduced by 70 per cent with the LED luminaires and the aim with a lighting replacement is to reduce the annual energy use by 50 percent. The average illuminance of the new LED lighting is about 680 lx meets the requirement for the average illuminance of 300 lx that applies to the packing room according to the standard SS-EN 12464-1: 2011. The life cycle cost of the old lighting and the new LED lighting was estimated at approximately 990,000 SEK and 330,000 SEK, respectively. The discounted payback time for the LED lighting was estimated at 1.7 years. Regarding the working environment, the LED lighting has been mounted at a luminaire height that is too low and will be raised to achieve a more comfortable working environment.

     

    Investing in a new energy-efficient lighting means a large reduction in annual energy use, while the investment has a relatively short repayment period. There are many advantages to replacing the old lighting such as an improved work environment and reduced costs for the company. Hopefully, more industries will replace their old lighting for energy-efficient lighting as they account for a large part of the total electricity use when it comes to lighting in Sweden.

  • 208.
    Björklund, Viktor
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Optimering av plocksignal2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Examensarbetet skrivs på Scania CV AB i Södertälje hos gruppen MSLT som arbetar inom logistikutveckling hos alla monteringsavdelningar hos chassimonteringen. Examensarbetet fokuserar på en av dessa monteringsavdelningar med benämningen FFU – Fit For Use och dess logistikgrupp MSLFL.

     

    Chassimonteringen är uppdelad i 14 antal områden längs med monteringslinan där varje område utför olika typer av monteringar och arbeten. I det stora hela fungerar det så att sidobalkar levereras i ena änden av fabriken och i den andra änden kommer en färdig lastbil ut. Under denna resa levereras och monteras det som en standardlastbil behöver.

    FFUs del i denna montering kommer in när en kund har speciella önskemål till sin lastbil, som då alltså frångår det som ingår i en standardlastbil. De olika monteringsarbetena som krävs vid de olika specifika önskemålen kan ej utföras på den ordinarie monteringslinan och utförs därför hos FFU. På FFU finns logistikavdelningen MSLFL vars uppgift är att plocka ihop och leverera materialet till monteringen hos FFU.

     

    Det problem som uppstår idag är att planeringen och tidpunkten för plocksignalen till logistikavdelningen MSLFL på FFU ej är optimal. Detta leder till att artiklar plockas från lager för tidigt och blir sen stående i väntan på montering. Detta ger i sin tur platsbrist hos MSLFL vid leveransytan till monteringen hos FFU. Materialet som behövs för monteringen på FFU plockas i ett för tidigt skede i förhållande till själva monteringen. Det är denna problematik som examensarbetet behandlat och undersökt.

     

    Examensarbetet är uppdelat i tre delar. Från start utförs en två veckor lång praktik hos logistikavdelningar på chassimonteringen. Sedan påbörja en empirisk undersökning som består av intervjuer med anställda på de påverkade avdelningarna, där syftet att hitta någon eventuell lösning. Den empiriska undersökningen utförs under fem veckor. Resterande tid läggs på att skriva rapport och planera redovisning som sker både hos Scania och vid Umeå universitet.

     

    Den empiriska undersökningen har lett fram till tre plausibla lösningar där förslag tre, att sätta ett eget Topp-CU till FFU anses som det bästa och mest relevanta då det skulle ändra förutsättningarna för planeringen hos FFU och MSLFL. Alla lösningsförslagen i denna rapport kräver dock vidare undersökningar i framtida projekt för optimering och eventuellt genomförande.

  • 209.
    Björnham, Alexandra
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Agile communication for a greener world2016Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As a research focused organization the problem with making the information easily read and interesting to the extent that the reader wants to share this information with its friends is a crucial one. To create the perfect communication, reaching and affecting the majority of society is an impossible task. If the focus instead lies on the thought that by building a serious and dependable reputation, using the ease of social media and trying to create a ripple effect to make change by networking communication, there is a possibility to influence.

    The art of persuasion starts by building trust in a person or in this case in an organization. But if the communication is made by social media, how can one tell if the communication has built trust or created any positive response by the readers?

    By using Python, a search algorithm has been set up for mining Twitter and analyzing all data covering the area of biofuel and its participants. This data is then used to start an information feedback loop, where the analytical conclusions made from the retrieved information and activities can affect the communication forwarded from the sender. In an agile manner the user is to choose “sprint”-time as well as a time for retrospect, all to refine the analytical method and improve the process.

  • 210.
    Björnham, Oscar
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics.
    A study of bacterial adhesion on a single-cell level by means of force measuring optical tweezers and simulations2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The intriguing world of microbiology is nowadays accessible for detailed exploration at a single–molecular level. Optical tweezers are a novel instrument that allows for non–invasive manipulation of single cells by the sole use of laser light and operates on the nano– and micrometer scale which corresponds to the same length scale as living cells. Moreover, forces within the field of microbiology are typically in the picoNewton range which is in accordance with the capability of force measuring optical tweezers systems. Both these conformabilities imply that force measuring optical tweezers is suitable for studies of single living cells. This thesis focuses on the mechanisms of bacterial attachments to host cells which constitute the first step in bacterial infection processes. Bacteria bind specifically to host receptors by means of adhesins that are expressed either directly on the bacterial membrane or on micrometer–long adhesion organelles that are called pili. The properties of single adhesin–receptor bonds that mediate adherence of the bacterium Helicobacter pylori are first examined at various acidities. Further on, biomechanical properties of P pili expressed by Escherichia coli are presented to which computer simulations, that capture the complex kinetics of the pili structure and precisely replicate measured data, are applied. Simulations are found to be a powerful tool for investigations of adhesive attributes of binding systems and are utilized in the analyses of the specific binding properties of P pili on a single–pilus level. However, bacterial binding systems generally involve a multitude of adhesin–receptor bonds. To explore bacterial attachments, the knowledge from single–pilus studies is brought into a full multipili attachment scenario which is analyzed by means of theoretical treatments and simulations. The results are remarkable in several aspects. Not only is it found that the intrinsic properties of P pili are composed in an optimal combination to promote strong multipili bindings. The properties of the pili structure itself are also found to be optimized with respect to its in vivo environment. Indeed, the true meaning of the attributes derived at a single–pilus level cannot be unraveled until a multipili–binding system is considered. Whereas detailed studies are presented for the helix–like P pili expressed by Gram–negative Escherichia coli, conceptual studies are presented for the open coil–like T4 pili expressed by Gram–positive Streptococcus pneumoniae. The structural and adhesive properties of these two types of pili differ considerably. These dissimilarities have far–reaching consequences on the adhesion possibilities at both single–pilus and multipili levels which are discussed qualitatively. Moreover, error analyses of conventional data processing methods in dynamic force spectroscopy as well as development of novel analysis methods are presented. These findings provide better understanding of how to perform refined force measurements on single adhesion organelles as well as how to improve the analyses of measurement data to obtain accurate parameter values of biomechanical entities. In conclusion, this thesis comprises a study of bacterial adhesion organelles and the way they cooperate to establish efficient attachment systems that can successfully withstand strong external forces that acts upon bacteria. Such systems can resist, for instance, rinsing effects and thereby allow bacteria to colonize their host. By understanding the complexity, and thereby possible weaknesses, of bacterial attachments, new targets for combating bacterial infections can be identified.

  • 211.
    Björnham, Oscar
    et al.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics.
    Axner, Ove
    Umeå University, Faculty of Science and Technology, Physics.
    Multipili Attachment of Bacteria with Helix–like Pili Exposed to Stress2009In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 130, p. 235102-Article in journal (Refereed)
    Abstract [en]

    A number of biomechanical properties of various types of pili expressed by Escherichia coli, predominantly their force–vs.–elongation behavior, have previously been assessed in detail on a single pilus level. In vivo, however, bacteria bind in general to host cells by a multitude of pili, which presumably provides them with adhesion properties that differs from those of single pili. Based upon the previously assessed biomechanical properties of individual pili, this work presents a theoretical analysis of the adhesion properties of multipili–attaching bacteria expressing helix–like pili exposed to an external force. Expressions for the adhesion lifetime of dual– and multipili–attaching bacteria are derived and their validity is verified by Monte Carlo simulations. It is shown that the adhesion lifetime of a multipili–binding bacterium depends to a large degree on the cooperativity of the attaching pili, which, in turn, depends strongly on their internal biomechanical properties, in particular their helix–like structure and its ability to elongate, which, in turn, depend on the intrinsic properties of the bonds, e.g. their lengths and activation energies. It is shown, for example, that a decrease in the length of a layer–to–layer bond in the rod of P pili, expressed by E. coli, by 50 % leads to a decrease in the adhesion lifetime of a bacterium attaching by 10 pili and exposed to a force of 500 pN by three orders of magnitude. The results indicate moreover that the intrinsic properties of the rod for this particular type of pili are optimized for multipili attachment under a broad range of external forces and presumably also to its in vivo environment. Even though the results presented in this work apply quantitatively to one type of pilus, they are assumed to apply qualitatively to all helix–like pili systems expressing slip bonds.

  • 212.
    Björnham, Oscar
    et al.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics.
    Axner, Ove
    Umeå University, Faculty of Science and Technology, Physics.
    Andersson, Magnus
    Umeå University, Faculty of Science and Technology, Physics.
    Modeling of the elongation and retraction of Escherichia coli P pili under strain by Monte Carlo simulations2008In: European Biophysics Journal, ISSN 0175-7571, E-ISSN 1432-1017, Vol. 37, no 4, p. 381-391Article in journal (Refereed)
    Abstract [en]

    P pili are fimbrial adhesion organelles expressed by uropathogenic Escherichia coli in the upper urinary tract. They constitute a stiff helix-like polymer consisting of a number of subunits joined by head-to-tail bonds. The elongation and retraction properties of individual P pili exposed to strain have been modeled by Monte Carlo (MC) simulations. The simulation model is based upon a three-state energy landscape that deforms under an applied force. Bond opening and closure are modeled by Bells theory while the elongation of the linearized part of the pilus is described by a worm-like chain model. The simulations are compared with measurements made by force measuring optical tweezers. It was found that the simulations can reproduce pili elongation as well as retraction, under both equilibrium and dynamic conditions, including entropic effects. It is shown that the simulations allow for an assessment of various model parameters, e.g. the unfolding force, energy barrier heights, and various distances in the energy landscape, including their stochastic spread that analytical models are unable to do. The results demonstrate that MC simulations are useful to model elongation and retraction properties of P pili, and therefore presumably also other types of pili, exposed to strain and/or stress. MC simulations are particularly suited for description of helix-like pili since these have an intricate self-regulating mechanical elongation behavior that makes analytical descriptions non-trivial when dynamic processes are studied, or if additional interactions in the rod or the behavior of the adhesion tip needs to be modeled.

  • 213.
    Björnham, Oscar
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Bugaytsova, Jeanna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Borén, Thomas
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Schedin, Staffan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Dynamic force spectroscopy of the Helicobacter pylori BabA-Lewis b binding2009In: Biophysical Chemistry, ISSN 0301-4622, E-ISSN 1873-4200, Vol. 143, no 1-2, p. 102-105Article in journal (Refereed)
    Abstract [en]

    The binding strength of the Helicobacter pylori adhesin–receptor complex BabA-ABO/Lewis b has been analyzed by means of dynamic force pectroscopy. High-resolution measurements of rupture forces were performed in situ on single bacterial cells, expressing the high-affinity binding BabA adhesin, by the use of force measuring optical tweezers. The resulting force spectra revealed the mechanical properties of a single BabA–Leb bond. It was found that the bond is dominated by one single energy barrier and that it is a slipbond. The bond length and thermal off-rate were assessed to be 0.86±0.07 nm and 0.015±0.006 s−1, respectively.

  • 214.
    Björnham, Oscar
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Fällman, Erik
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Axner, Ove
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Ohlsson, J.
    Nilsson, U.J.
    Borén, Thomas
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Schedin, Staffan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Measurements of the binding force between the Helicobacter pylori adhesin BabA and the Lewis b blood group antigen using optical tweezers2005In: Journal of Biomedical Optics, ISSN 1560-2281 (Online), Vol. 10, no 4, p. 044024-Article in journal (Refereed)
    Abstract [en]

    Helicobacter pylori is a world-wide spread bacterium that causes persistent infections and chronic inflammations that can develop into gastritis and peptic ulcer disease. It expresses several adhesin proteins on its surface that bind to specific receptors in the gastric epithelium. The most well-known adhesin is BabA, which has previously been shown to bind specifically to the fucosylated blood group antigen Lewis b (Leb). The adhesion forces between BabA and the Leb antigen are investigated in this work and assessed by means of optical tweezers. A model system for in situ measurements of the interaction forces between individual bacteria and beads coated with Leb is developed. It is found that the de-adhesion force in this model system, measured with a loading rate of approximately 100 pNs, ranges from 20 to 200 pN. The de-adhesion force appears predominantly as multiples of an elementary force, which is determined to 25+/-1.5 pN and identified as the unbinding force of an individual BabA-Leb binding. It is concluded that adhesion in general is mediated by a small number of bindings (most often 1 to 4) despite that the contact surface between the bacterium and the bead encompassed significantly more binding sites.

  • 215.
    Björnham, Oscar
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nilsson, Håkan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Andersson, Magnus
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Schedin, Staffan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Physical properties of the specific PapG–galabiose binding in E. coli P pili-mediated adhesion2009In: European Biophysics Journal, ISSN 0175-7571, E-ISSN 1432-1017, Vol. 38, no 2, p. 245-254Article in journal (Refereed)
    Abstract [en]

    Detailed analyses of the mechanisms thatmediate binding of the uropathogenic Escherichia coli tohost cells are essential, as attachment is a prerequisite forthe subsequent infection process. We explore, by means offorce measuring optical tweezers, the interaction betweenthe galabiose receptor and the adhesin PapG expressed byP pili on single bacterial cells. Two variants of dynamicforce spectroscopy were applied based on constant andnon-linear loading force. The specific PapG–galabiosebinding showed typical slip-bond behaviour in the forceinterval (30–100 pN) set by the pilus intrinsic biomechanicalproperties. Moreover, it was found that the bondhas a thermodynamic off-rate and a bond length of2.6×10-3 s-1 and 5.0 Å , respectively. Consequently, thePapG–galabiose complex is significantly stronger thanthe internal bonds in the P pilus structure that stabilizes thehelical chain-like macromolecule. This finding suggeststhat the specific binding is strong enough to enable the Ppili rod to unfold when subjected to strong shear forces inthe urinary tract. The unfolding process of the P pili rodpromotes the formation of strong multipili interaction,which is important for the bacterium to maintain attachmentto the host cells.

  • 216.
    Björnham, Oscar
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Schedin, Staffan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Methods and error estimations of uncertainties in single-molecule dynamic force spectroscopy2009In: European Biophysics Journal, ISSN 0175-7571, E-ISSN 1432-1017, Vol. 38, no 7, p. 911-922Article in journal (Refereed)
    Abstract [en]

    In dynamic force spectroscopy, access to the characteristic parameters of single molecular bonds requires non-trivial measurements and data processing as the rupture forces are found not only to be distributed over a wide range, but are also dependent on the loading rate. The choice of measurement procedure and data processing methods has a considerable impact on the accuracy and precision of the final results. We analyse, by means of numerical simulations, methods to minimize and assess the magnitude of the expected errors for different combinations of experimental and evaluation methods. It was found that the choice of fitting function is crucial to extract correct parameter values. Applying a Gaussian function, which is a common practice, is equivalent to introducing a systematic error, and leads to a consequent overestimation of the thermal off-rate by more than 30%. We found that the precision of the bond length and the thermal off-rate, in presence of unbiased noise, were improved by reducing the number of loading rates for a given number of measurements. Finally, the results suggest that the minimum number of measurements needed to obtain the bond strength, with acceptable precision, exceeds the common number of ~100 reported in literature.

     

  • 217. Blank, Vladimir D.
    et al.
    Buga, Sergey G.
    Dubitsky, Gennadii A.
    Serebryanaya, Nadejda R.
    Popov, M. Yu.
    Kulnitskiy, B.A.
    Prokhorov, V.M.
    Levin, V.M.
    Zhu, Xiaomei
    Nyeanchi, Emmanuel
    Sundqvist, Bertil
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Fransson, Åke
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    High-pressure synthesis, structure and properties of superhard and ultrahard fullerites2000In: High Pressure - 2000: Proceedings of the VI International Conference on High Pressure, Donetsk, Ukraina: Donetsk Intitute for Physics and Engineering , 2000, p. 127-132Conference paper (Refereed)
  • 218.
    Blomberg, Camilla
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Wordpress som CMS för mindre webbplatser2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Alla som studerar till Medieproducent på Umeå Universitet ska i slutet av utbildningen genomföra ett examensarbete. Syftet är att visa de kunskaper som utbildningen givit och i samma veva inhämta nya. Detta examensarbete är utfört på beställning av byggföretaget Gottfridsson o Persson Construction AB. Målet var att ta fram en enkel webbplats som skulle vara lätt att underhålla och inbringa nya kunder till företaget. Rapporten tar i första delen upp bakgrunden till detta projekt, dess syfte, förutsättningar det haft samt avgränsningar som gjorts. I den andra delen redogörs bland annat teoretiska delar kring hur en webbplats skapas med Wordpress, vilka för- och nackdelar som finns och ett antal viktiga punkter att tänka på. Den tredje delen  av rapporten beskriver hur arbetet gått till och vilka metoder som användts. Slutligen redovisas resultatet och en diskussion kring hur arbetet gått, samt slutsatser som dragits.

  • 219.
    Blomberg, Hans
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Korta instruktionsvideor inom matlagning2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract  

    This  report  describes  the  production  of  a  number  of  short  instructional  videos  in  cooking.  The  project  was  a  thesis  project  for  Högskoleprogrammet  till  medieproducent,  which  is  a  two-­‐year  program  for  media  production  at  Umeå  University.  

    Video  production  took  place  at  the  request  of  SVT  (Swedish  television)  in  Umeå.  The  videos  are  meant  to  be  used  on  the  cooking  portal  SVT  plans  to  launch  in  the  fall  of  2015.  A  chef  was  hired  to  carry  out  the  procedures  to  be  filmed,  and  the  student  was  assigned  to  shoot  and  edit  everything.  

    Before  production  started,  cooking  instructionals  on  Youtube  were  analyzed,  to  create  an  idea  of  how  such  videos  typically  look  today.  The  results  of  this  analysis  were  then  used  in  the  production,  but  they  were  not  governing  in  the  design,  since  specific  requests  from  others  involved,  and  specific  conditions  of  the  project  existed.  Also  the  student's  own  visions  influenced  the  outcome.  Another  preparation  was  to  set  up  various  options  for  the  design  and  assessing  what  these  different  options  would  mean  for  the  result.  

    Shooting  took  place  in  the  chef's  kitchen,  during  three  days.  Each  video  was  filmed  from  two  angles,  to  facilitate  cutting  therebetween.  The  material  was  edited  with  the  aim  to  convey  both  clarity  and  good  aesthetics.    

    The  experience  resulted  in  recommendations  for  further  work,  in  the  form  of  a  manual  of  how  to  produce  such  cooking  tutorials.  The  manual  describes  what  equipment  is  needed  and  how  to  work  on  set.  Then  the  editing  process,  including  appropriate  lengts  of  the  videos,  is  presented.  The  manual  also  contains  recommendations  for  how  much  time  is  needed  when  producing  a  certain  number  of  short  instructional  videos  of  this  kind. 

  • 220.
    Blomdahl, Pontus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utmattningsprovning av kamringar: Framtagning av testutrustning för utmattningsprovning av kamringar2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Bosch Rexroth in Mellansel develops and fabricates Hägglunds hydraulic motors among other things. One important component of the motor is the cam ring, which commonly affects the life span of the motor. The aim is to create the basis of a testing equipment where a loose cam ring can be tested. Previously, a complete motor has been used in order to test the fatigue resistance of the cam ring. In order to load the cam ring similar to the real case. FEM-analysis was performed to investigate how the cam ring is affected during loading and how the rig should be built for the strains to be similar to the real case. The result of this simulation was compiled in a Haighdiagram in order to get an indication of the magnitude of the stresses. The solution is a testing equipment which consist of a cylinder block which usually is in the motor. The cylinder block is bolted onto a bottom plate where the cam ring has a given position. The cam ring is fixated using a sloted spring pin and a dowel pin that keeps the cam ring in position and prevents potential torque. All pistons should be pressurised by pulsation at the same time using the same pressure, thus, the torque is expected to be zero. One of the holes which is holding the cam ring is oval, this is to allow deformation of the cam ring. The result of this work is a basic plan for the components included which affects the mechanical function of the testing equipment. A limitation of this work has been that the residual stresses in the clearance holes is unknown. These residual stresses have a great importance for fatigue resistance of the cam rings. As a consequence of this, it has been difficult to estimate which working pressure the test rig has to use in order to achieve the desired life span. Experimental testing when using the rig will indicate this. Task monotoring  The testing equipment will generate 1-10 million loading cycles before failure of the cam ring occurs. Will be achieved through experimental testing  Testing time should be reasonable, result would preferably be achieved within 2-4 weeks. Will be achieved through experimental testing  The testing equipment should be customised for a CA 50-50 cam ring. (CA 50 motor series strongest motor 50 Nm/bar) Achieved  Testing equipment should be usable with the current laboratory equipment of Bosh Rexroths (420 bars maximum preassure). Probably achieved  The crack needs to be detected in an appropriate way, to stop the testing. Achieved  The testing equipment needs to be able to be manufactured by using the developed blueprints. Achieved

  • 221.
    Blomqvist, Benjamin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Rönntoft, Britta
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Jet flow simulations of Baihetan hydropower station’s discharge surface spillways2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This project was performed in order to determine if numerical simulations can be used to predict the spreading of a water jet that exits the discharge surface spillways of Baihetan hydropower station. If the spreading ranges can be predicted correctly using numerical simulations, the pressure distribution in the plunge pool downstream the dam can be determined. By being able to determine the pressure distribution, the spillways’ design can then be modified in order to optimize the pressure distribution and thereby minimize the damage on the plunge pool’s river bed. If the spreading ranges can be predicted correctly using numerical simulations it means that numerical simulations can be used as a tool to design future hydropower stations’ discharge surface spillways as a substitute to scale models which are commonly used to optimize the spillway design today.

    A simulation model of Baihetan Hydropower station’s discharge surface spillways was constructed. The model was constructed as two separate parts using the pre-processing software Gambit and then imported to the computational fluid dynamics software Fluent for numerical simulation of the water flow. The numerical simulations were performed with a transient flow, the k-ε turbulence model and the Volume of Fluid multiphase model. The models were simulated with a water level in the dam corresponding to when a massive flood has occurred which happens approximately once every hundred years. The results from the numerical simulation were then analyzed with the post-processing software Tecplot 360. Results in form of water spreading ranges when the jet stream hits the plunge pool were obtained from the numerical simulation and compared to data from an earlier performed experimental study where a scale model was used. The water spreading ranges were measured using a water volume fraction of 0-5 percent. The comparison was done to be able to determine if the results from the numerical simulations were accurate enough so that numerical simulations could be used as a substitute to expensive scale models when designing hydropower stations’ discharge surface spillways. A sensitivity analysis was performed where different mesh sizes were used and the Fluent setting double precision mode.

    The numerical results were acceptable when checking for convergence, meaning that the equations involved in the simulations were solved properly. The relative difference in water spreading range in the direction of the flow for the Medium mesh size was below 20 percent and thereby considered acceptable while the relative difference in water spreading range perpendicular to the flow was 60 percent for the Medium mesh size and thereby far from acceptable. Possible reasons for these deviations from the experimental results are the approximated uniform velocity profile at the inlet of the spillway and the used k-ε turbulence model. Considering the results obtained in this project, without more detailed study, the numerical simulations using k-ε turbulence model are not advised as a substitute for the experimental methods to determine water flow out of the discharge spill ways of hydropower plants. With more information about the conditions at the inlet and the use of a different turbulence model more accurate results may be obtained. 

  • 222. Bobtsov, A. A.
    et al.
    Nikolaev, N. A.
    Slita, O. V.
    Borgul, A. S.
    Aranovskiy, Stanislav
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    The new algorithm of sinusoidal signal frequency estimation2013In: Adaptation and Learning in Control and Signal Processing, 2013, no PART, p. 182-186Conference paper (Refereed)
    Abstract [en]

    In this paper we consider the new estimation algorithm of the measured sinusoidal signal frequency. Unlike most of known similar methods, the proposed algorithm provides the opportunity of partial rejection of unaccounted disturbances presenting in the channel of useful signal measurement. The latter in its turn allows obtaining more accurate estimation of unknown frequency of the measured sinusoidal signal.

  • 223.
    Bohman, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Single Sign On med Azure AD Connect2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report covers Azure AD Connect and Single/Simplified Sign On. Users and customers today places greater demand for easier login method and seamless experience for reaching all services. Microsoft has recently released Azure AD Connect tool to help synchronize passwords between Active Directory and the cloud services Office 365/Azure and 1000s of Software as a service applications. Team Norr IT-partner is an IT company that focuses on delivering Microsoft products to thier customers and therefore wanted to know more about Azure AD Connect. How to configure the solution and what the set requirements are.

    Single Sign On means that you only need to sign in with password and login once and automatically get access the applications that support the technology without any more credentials.  By using a Federated domain users get the best and safest experience with Single Sign On. Simplified Sign On lets users use the same username and password to login with to all applications with support, but no automatic login.

    Azure AD Connect tool installs the roles that are needed to run a Single Sign On or Simplified Sign On. By default the synchronization engine will keep track of information about the users and groups. Passwords are also synchronized between on-premises Active Directory and Azure Active Directory or federation server.

    What the Synchronization engine takes is determined by the rules defined. Password Sync does not install any extra server roles. With the Federation path there will be extra roles installed called Federation (AD FS) and Web Application Proxy (WAP). They handle the authentication of users instead of the normal Microsoft authentication. There is some set requirement for the servers that host the roles depending on the size of Active Directory and numbers of users. The servers need a certain base performance for it to work properly. 

  • 224. Bolling, Anette Kocbach
    et al.
    Pagels, Joakim
    Yttri, Karl Espen
    Barregard, Lars
    Sallsten, Gerd
    Schwarze, Per E
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Health effects of residential wood smoke particles: the importance of combustion conditions and physicochemical particle properties2009In: Particle and Fibre Toxicology, ISSN 1743-8977, E-ISSN 1743-8977, Vol. 6, article id 29Article, review/survey (Refereed)
    Abstract [en]

    Background: Residential wood combustion is now recognized as a major particle source in many developed countries, and the number of studies investigating the negative health effects associated with wood smoke exposure is currently increasing. The combustion appliances in use today provide highly variable combustion conditions resulting in large variations in the physicochemical characteristics of the emitted particles. These differences in physicochemical properties are likely to influence the biological effects induced by the wood smoke particles.

    Outline: The focus of this review is to discuss the present knowledge on physicochemical properties of wood smoke particles from different combustion conditions in relation to wood smoke-induced health effects. In addition, the human wood smoke exposure in developed countries is explored in order to identify the particle characteristics that are relevant for experimental studies of wood smoke-induced health effects. Finally, recent experimental studies regarding wood smoke exposure are discussed with respect to the applied combustion conditions and particle properties.

    Conclusion: Overall, the reviewed literature regarding the physicochemical properties of wood smoke particles provides a relatively clear picture of how these properties vary with the combustion conditions, whereas particle emissions from specific classes of combustion appliances are less well characterised. The major gaps in knowledge concern; (i) characterisation of the atmospheric transformations of wood smoke particles, (ii) characterisation of the physicochemical properties of wood smoke particles in ambient and indoor environments, and (iii) identification of the physicochemical properties that influence the biological effects of wood smoke particles.

  • 225.
    Boman, B Christoffer
    et al.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Forsberg, A Bertil
    Järvholm, Bengt G
    Adverse health effects from ambient air pollution in relation to residential wood combustion2003In: Scandinavian Journal of Work, Environment and Health, Vol. 29, no 4, p. 251-260Article in journal (Refereed)
  • 226.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics.
    Particulate and gaseous emissions from residential biomass combustion2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Biomass is considered to be a sustainable energy source with significant potentials for replacing electricity and fossil fuels, not at least in the residential sector. However, present wood combustion is a major source of ambient concentrations of hydrocarbons (e.g. VOC and PAH) and particulate matter (PM) and exposure to these pollutants have been associated with adverse health effects. Increased focus on combustion related particulate emissions has been seen concerning the formation, characteristics and implications to human health. Upgraded biomass fuels (e.g. pellets) provide possibilities of more controlled and optimized combustion with less emission of products of incomplete combustion (PIC´s). For air quality and health impact assessments, regulatory standards and evaluations concerning residential biomass combustion, there is still a need for detailed emission characterization and quantification when using different fuels and combustion techniques.

    This thesis summarizes the results from seven different papers. The overall objective was to carefully and systematically study the emissions from residential biomass combustion with respect to: i) experimental characterization and quantification, ii) influences of fuel, appliance and operational variables and iii) aspects of ash and trace element transformations and aerosol formation. Special concern in the work was on sampling, quantification and characterization of particulate emissions using different appliances, fuels and operating procedures.

    An initial review of health effects showed epidemiological evidence of potential adverse effect from wood smoke exposure. A robust whole flow dilution sampling set-up for residential biomass appliances was then designed, constructed and evaluated, and subsequently used in the following emission studies. Extensive quantifications and characterizations of particulate and gases emissions were performed for residential wood and pellet appliances. Emission factor ranges for different stoves were determined with variations in fuel, appliance and operational properties. The emissions of PIC´s as well as PMtot from wood combustion were in general shown to be considerably higher compared to pellets combustion. PAHtot emissions were determined in the range of 1300-220000 µg/MJ for wood stoves and 2-300 µg/MJ for pellet stoves with phenantrene, fluoranthene and pyrene generally found as major PAH´s. The PM emissions from present residential appliances was found to consist of significant but varying fractions of PIC´s, with emissions in the range 35-350 mg/MJ for wood stoves compared to 15-45 mg/MJ for pellet stoves. Accordingly, the use of up-graded biomass fuels, combusted under continuous and controlled conditions give advantageous combustion conditions compared to traditional batch wise firing of wood logs. The importance of high temperature in well mixed isothermal conditions was further illustrated during pellets combustion to obtain complete combustion with almost a total depletion of PIC´s. Fine (100-300 nm) particles dominated in all studied cases the PM with 80-95% as PM1. Beside varying fractions of carbonaceous material, the fine PM consisted of inorganic volatilized ash elements, mainly found as KCl, K3Na(SO4)2 and K2SO4 with mass concentrations at 15-20 mg/MJ during complete combustion. The importance of the behavior of alkali elements for the ash transformation and fine particle formation processes was further shown, since the stability, distributions and compositions also directly control the degree of volatilization. In addition to the alkali metals, zinc was found as an important element in fine particles from residential biomass combustion. Finally, the behaviour of volatile trace elements, e.g. Zn and Cd, during pellets production and combustion were studied. A significant enrichment in the pellet fuel during the drying process was determined. The magnitude and importance of the enrichment was, however, relative small and some alternative measures for prevention were also suggested.

  • 227.
    Boman, Christoffer
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Forsberg, B
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Sandström, Thomas
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Pulmonary Medicine.
    Shedding new light on wood smoke: a risk factor for respiratory health.2006In: Eur Respir J, ISSN 0903-1936, Vol. 27, no 3, p. 446-7Article in journal (Refereed)
  • 228.
    Boman, Christoffer
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Öhman, Marcus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Characterization of inorganic particulate matter from residential combustion of pelletized biomass fuels2004In: Energy and Fuels, ISSN 0887-0624, Vol. 18, no 2, p. 338-348Article in journal (Refereed)
    Abstract [en]

    The increased focus on potential adverse health effects associated with exposure to ambient particulate matter (PM) motivates a careful characterization of particle emissions from different sources. Combustion is a major anthropogenic source of fine PM, and, in urban areas, traditional residential wood combustion can be a major contributor. New and upgraded biomass fuels have become more common, and fuel pellets are especially well-suited for the residential market. The objective of the present work was to determine the mass size distributions, elemental distributions, and inorganic-phase distributions of PM from different residential combustion appliances and pelletized biomass fuels. In addition, chemical equilibrium model calculations of the combustion process were used to interpret the experimental findings. Six different typical pellet fuels were combusted in three different commercial pellet burners (10−15 kW). The experiments were performed in a newly designed experimental setup that enables constant-volume sampling. Total-PM mass concentrations were measured using conventional filters, and the fractions of products of incomplete combustion and inorganic material were thermally determined. Particle mass size distributions were determined using a 13-step low-pressure cascade impactor with a precyclone. The PM was analyzed for morphology (using environmental scanning electron microscopy, ESEM), elemental composition (using energy-dispersive spectroscopy, EDS), and crystalline phases (using X-ray diffractometry, XRD). For complementary chemical structural characterization, time-of-flight secondary ion mass spectrometry (TOF−SIMS), X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) spectroscopy were also used. The emitted particles were mainly found in the fine (<1 μm) mode with mass median aerodynamic diameters of 0.20−0.39 μm and an average PM1 of 89.5% ± 7.4% of total PM. Minor coarse-mode fractions (>1 μm) were present primarily in the experiments with bark and logging residues. Relatively large and varying amounts (28%−92%) were determined to be products of incomplete combustion. The inorganic elemental compositions of the fine particles were dominated by potassium, chlorine, and sulfur, with minor amounts of sodium and zinc. The dominating alkali phase was KCl, with minor but varying amounts of K3Na(SO4)2 and, in some cases, also K2SO4. The results showed that zinc is almost fully volatilized, subsequently and presumably forming a more complex solid phase than that previously suggested (ZnO). However, the formation mechanism and exact phase identification remain to be elucidated. With some constrains, the results also showed that the amounts and speciation of the inorganic PM seemed to be quite similar to that predicted by chemical equilibrium calculations.

  • 229.
    Boman, Christoffer
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Westerholm, Roger
    Pettersson, Esbjörn
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Evaluation of a constant volume sampling set-up for residential biomass fired appliances: influence of dilution conditions on particulate and PAH emissions2005In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 29, no 4, p. 258-268Article in journal (Refereed)
    Abstract [en]

    Increased concerns about particulate matter (PM) and polycyclic aromatic hydrocarbons (PAH) emissions from residentialbiomass combustion and their potential health effects, motivates detailed emission measurements under controlled conditions. Traditional sampling in raw flue gases can suffer from drawbacks mainly related to transient flows and the condensable nature of organic compounds. Whole flow dilution with constantvolumesampling (CVS) is an alternative method but different samplingconditions may, however, influence the emission characteristics. The objective was to design a CVS system for emission measurements in residentialbiomassfiredappliances and determine the influence of dilutionsamplingconditions on the characteristics and distributions of PM and PAH. Softwood pellets were combusted in a pellet stove with variations in; dilution ratio (3–7x), sampling temperature (45–75 °C), dilution tunnel residence time (2–4 s) and fuel load (2.3 and 4.8 kW) according to a statistical experimental design. The samplingconditions did not influence either the emission concentrations of PM, CO and NO or the particle size distribution. Variations in residence time had no significant effect on any studied emission parameter. However, increased concentrations of organic gaseous carbon (OGC) and PAH were observed with increased dilution ratio. The distribution between particulate and semivolatile phase was influenced for 12 of the 37 analyzed PAH compounds, mainly by increased fractions of semivolatile material at higher sampling temperature. No influence of sampling temperature was observed for the concentrations of PAHtot or the dominating PAH compounds, i.e. phenanthrene, fluoranthene and pyrene. The results together with practical considerations also suggest sampling at 50±5 °C and 3–4 times dilution as robust and applicable conditions in the presently designed setup.

  • 230.
    Boman, Christoffer
    et al.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics.
    Pettersson, Esbjörn
    Lindmark, Fredrik
    Öhman, Marcus
    Nordin, Anders
    Westerholm, Roger
    Effects of temperature and residence time on emission characterstics during fixed-bed combustion of conifer stem-wood pellets.Manuscript (Other academic)
  • 231.
    Boman, Christoffer
    et al.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics.
    Pettersson, Esbjörn
    Nordin, Anders
    Westerholm, Roger
    Boström, Dan
    Gaseous and particulate emissions from combustion in residential wood log and pellet stoves-experimental characterization and quantificationManuscript (Other academic)
  • 232.
    Boman, Christoffer
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Pettersson, Esbjörn
    Energy Technology Centre, Piteå, Sweden.
    Westerholm, Roger
    Department of Analytical Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Stove performance and emission characteristics in residential wood log and pellet combustion: Part 1: Pellet stoves2011In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, no 1, p. 307-314Article in journal (Refereed)
    Abstract [en]

    Stove performance, characteristics, and quantities of gaseous and particulate emissions were determined for two different pellet stoves, varying fuel load, pellet diameter, and chimney draft. This approach aimed at covering variations in emissions from stoves in use today. The extensive measurement campaign included CO, NOx, organic gaseous carbon, volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), total particulate matter (PMtot) as well as particle mass and number concentrations, size distributions, and inorganic composition. At high load, most emissions were similar. For stove B, operating at high residual oxygen and solely with primary air, the emissions of PMtot and particle numbers were higher while the particles were smaller. Lowering the fuel load, the emissions of CO and hydrocarbons increased dramatically for stove A, which operated continuously also at lower fuel loads. On the other hand for stove B, which had intermittent operation at lower fuel loads, the emissions of hydrocarbons increased only slightly lowering the fuel load, while CO emissions increased sharply, due to high emissions at the end of the combustion cycle. Beside methane, dominating VOCs were ethene, acetylene, and benzene and the emissions of VOC varied in the range 1.1−42 mg/MJfuel. PAH emissions (2−340 μg/MJfuel) were generally dominated by phenanthrene, fluoranthene and pyrene. The PMtot values (15−45 mg/MJfuel) were in all cases dominated by fine particles with mass median diameters in the range 100−200 nm, peak mobility diameters of 50−85 nm, and number concentrations in the range 4 × 1013 to 3 × 1014 particles/MJfuel. During high load conditions, the particulate matter was totally dominated by inorganic particles at 15−25 mg/MJfuel consisting of potassium, sodium, sulfur, and chlorine, in the form of K2SO4, K3Na(SO4)2, and KCl. The study shows that differences in operation and modulation principles for the tested pellet stoves, relevant for appliances in use today, will affect the performance and emissions significantly, although with lower scattering in the present study compared to compiled literature data.

  • 233.
    Boman, Christoffer
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Schmidt, Florian M.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ash transformation chemistry in biomass fixed beds with focus on slagging and aerosols: 20 years of research and new developments2017In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 254Article in journal (Other academic)
  • 234.
    Boman, Christoffer
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Trace element enrichment and behavior in wood pellet production and combustion processes.Manuscript (Other academic)
  • 235.
    Boman, Christoffer
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå tekniska universitet.
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Trace element enrichment and behaviour in wood pellet production and combustion processes2006In: Energy and Fuels, Vol. 20, p. 993-1000Article in journal (Refereed)
  • 236.
    Boman, Emil
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Korrosion i avfallsförbränningspannor: - med en fördjupad studie av korrosion på överhettare2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Inspecta AB bedriver besiktning som en av deras huvudsysslor och besiktar värmekraftverket på Dåvamyran. Besiktning av pannan sker årligen. Detta är ett krav från arbetsmiljöverket genom AFS 2005:3 ”Besiktning av trycksatta anordningar”. Pannan gås igenom med avseende på säkerhet och kan om den inte anses uppfylla de ställda krav bli underkänd för drift. I besiktningen ingår besiktning av överhettartuberna och man har noterat att tuberna i överhettar 2 har börjat korrodera med en ökad hastighet.

    Anledningen till varför korrosionshastigheten ökat har inte kunnat fastställas, men en av anledningarna kan vara att sopsorteringen i samhället ökat. Problemen som uppstått kan man härleda till bränslet. Avfall är ett väldigt heterogent bränsle, vilket innebär att värmevärdet och sammansättningen varierar väldigt mycket. Detta leder till problem som orsakar kostsamma planerade och oplanerade stopp. För att minska problemen som uppstår kan man vidta åtgärder som att tillsätta additiv och byta tubmaterialet.

    Den korrosion som verifierades med hjälp av SEM/EDS-analysen var högtemperaturkorrosion i form av klorinducerad korrosion, detta ska dock inte ses som ett entydigt svar då endast en tub, som suttit på kanten av överhettaren blev analyserad. Den materialanalys som gjordes visade att materialstrukturen varit opåverkad.

    Umeå energi hade vidtagit tre åtgärder, vilka var att: skydda tubernas böjar med ett keramiskt material, sänka ångtemperaturen och byte av tubmaterial. Skyddet på tuberna visade sig inte fungerar då de slagits sönder av sotningen. Sänkningen av ångtemperaturen blev installerad 2011 och man hittade klorinducerade korrosion 2012 vilket leder till slutsatsen att den inte stoppat denna typ av korrosion. Materialet som Umeå energi hade valt till tuberna var Inconel 625 påsvetsad på ett låglegerat stål. Materialet har visat goda egenskaper i kloridrika miljöer och kommer högst sannolikt ge ett bra resultat, men till en initialt hög kostnad. En alternativ åtgärd skulle vara att prova att tillsätta svavel som additiv med bränslet. Det har visat sig ge bra resultat i tidigare studier.

  • 237.
    Bonthron, Jonatan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Förstudie för etablering av vindkraft vid Dåva kraftvärmeverk2011Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
  • 238.
    Borg, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ny modell av lyftpunkt: En teoretisk och praktisk utredning av dess bärförmåga2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Lättelement AB designs and manufactures building elements in the form of ceilings, walls and floor tiles for the Nordic market. The majority are roof elements and the main market is Sweden. Each element has 4 lifting points. Lifting points are used for lifting elements, pulling together elements as well as attachment for fall protection equipment. Lättelement AB has designed a new model of lifting point that they want tested and intend to replace the current lifting point if the new model has the same or better capacity.

    The purpose of this work is to investigate if the new model of lifting point manages the forces that arise during its applications. This new model would facilitate the manufacture and assembly of lifting points.

    According to the theoretical calculations, the new model of lifting point would have better capacity than the current one. During tensile testing, unforeseen material failure were shown and the practical values ​​were significantly lower than expected. After tensile testing, the load capacity was calculated based on the current material failure and it was found that the calculations and test results are relatively well matched. Based on the requirements set for the new model of lifting point, the desired strength values ​​are not achieved to replace the current model.

    However, this work is a good basis for further development of the lifting point. Now it is known what happens at the material failure for this kind of lifting point. It provides an opportunity to construct a lifting point that will handle the desired capacity while at the same time being flexible from a production engineering perspective. 

  • 239.
    Borgström, Jonas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Mätning av hjulvarvshastighet med mikrokontroller2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 240.
    Borén, Eleonora
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Off-gassing from thermally treated lignocellulosic biomass2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Off-gassing of hazardous compounds is, together with self-heating and dust explosions, the main safety hazards within large-scale biomass storage and handling. Formation of CO, CO2, and VOCs with concurrent O2 depletion can occur to hazardous levels in enclosed stored forest products. Several incidents of CO poisoning and suffocation of oxygen depletion have resulted in fatalities and injuries during cargo vessel discharge of forest products and in conjunction with wood pellet storage rooms and silos. Technologies for torrefaction and steam explosion for thermal treatment of biomass are under development and approaching commercialization, but their off-gassing behavior is essentially unknown.

    The overall objective of this thesis was to provide answers to one main question: “What is the off-gassing behaviour of thermally treated lignocellulosic biomass during storage?”. This was achieved by experimental studies and detailed analysis of off-gassing compounds sampled under realistic conditions, with special emphasis on the VOCs.

    Presented results show that off-gassing behavior is influenced by numerous factors, in the following ways. CO, CO2 and CH4 off-gassing levels from torrefied and stream-exploded biomass and pellets, and accompanying O2 depletion, are comparable to or lower than corresponding from untreated biomass. The treatments also cause major compositional shifts in VOCs; emissions of terpenes and native aldehydes decline, but levels of volatile cell wall degradation products (notably furans and aromatics) increase. The severity of the thermal treatment is also important; increases in torrefaction severity increase CO off-gassing from torrefied pine to levels comparable to emissions from conventional pellets, and increase O2 depletion for both torrefied chips and pellets. Both treatment temperature and duration also influence degradation rates and VOC composition. The product cooling technique is influential too; water spraying in addition to heat exchange increased CO2 and VOCs off-gassing from torrefied pine chips, as well as O2 depletion. Moreover, the composition of emitted gases co-varied with pellets’ moisture content; pellets of more severely treated material retained less moisture, regardless of their pre-conditioning moisture content. However, no co-variance was found between off-gassing and pelletization settings, the resulting pellet quality, or storage time of torrefied chips before pelletization. Pelletization of steam-exploded bark increased subsequent VOC off-gassing, and induced compositional shifts relative to emissions from unpelletized steam-exploded material. In addition, CO, CO2 and CH4 off-gassing, and O2 depletion, were positively correlated with the storage temperature of torrefied softwood. Similarly, CO and CH4 emissions from steam-exploded softwood increased with increases in storage temperature, and VOC off-gassing from both torrefied and steam-exploded softwood was more affected by storage temperature than by treatment severity. Levels of CO, CO2 and CH4 increased, while levels of O2 and most VOCs decreased, during storage of both torrefied and steam-exploded softwood.CO, CO2 and O2 levels were more affected by storage time than by treatment severity. Levels of VOCs were not significantly decreased or altered by nitrogen purging of storage spaces of steam-exploded or torrefied softwood, or controlled headspace gas exchange (intermittent ventilation) during storage of steam-exploded bark.

    In conclusion, rates of off-gassing of CO and CO2 from thermally treated biomass, and associated O2 depletion, are comparable to or lower than corresponding rates for untreated biomass. Thermal treatment induces shifts in both concentrations and profiles of VOCs. It is believed that the knowledge and insights gained provide refined foundations for future research and safe implementation of thermally treated fuels as energy carriers in renewable energy process chains.

  • 241.
    Borén, Eleonora
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Kajsa, Werner
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Pommer, Linda
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Defining the temperature regime of gaseous degradation products of Norway spruce2013In: 21nd European Biomass Conference and Exhibition, Copenhagen, June, 2013, ETA Florens Renewable Energies, 2013, 2013Conference paper (Other academic)
  • 242.
    Borén, Eleonora
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Industrial Doctoral School for Research and Innovation, Umeå University, Umeå, Sweden.
    Larsson, Sylvia H.
    Biomass Technology Centre, Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Andreas, Averheim
    Mikael, Thyrel
    Biomass Technology Centre, Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Reducing VOC off-gassing during the production of pelletized steam-exploded bark: impact of storage time and controlled ventilation2018In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, no 4, p. 5181-5186Article in journal (Refereed)
    Abstract [en]

    Volatile organic compound (VOC) off-gassing behavior of thermally treated biomass intended for bioenergy production has recently been shown to be vastly different from that of untreated biomass. Simple measures to reduce emissions, such as controlled ventilation and prolonged storage time, have been suggested but not yet studied in detail. In the present study, we monitored how VOC off-gassing was reduced over time (24–144 h) in enclosed storage with and without ventilation. Steam-exploded bark was collected directly from a pilot-scale steam explosion plant as well as before and after subsequent pelletizing. Active Tenax-TA absorbent sampling of VOCs was performed from the headspaces of a bench-scale sample storage setup. The impact of storage time and ventilation on VOC levels was evaluated through multivariate statistical analysis. The results showed that relative VOC concentrations in the headspace were reduced by increased storage time, with heavier VOCs reduced at a higher rate. VOC composition was neither reduced nor shifted by controlled intermittent ventilation during storage; instead, VOC levels equilibrated at the same levels as those stored without ventilation, and this was independent of the process step, storage time, or number of ventilations.

  • 243.
    Borén, Eleonora
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Larsson, Sylvia H.
    Averheim, Andreas
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Reducing VOCs off-gassing during production of pelletized steam exploded bark: impact of storage time and controlled ventilationManuscript (preprint) (Other academic)
    Abstract [en]

    VOC off-gassing behavior of thermally treated biomass intended for bioenergy production has recently been shown to be vastly different to that of untreated biomass. Simple measures to reduce emissions, such as controlled ventilation and prolonged storage time, has been suggested but not previously studied in detail. In the present study, we monitored how VOC off-gassing was reduced over time (24–144h) in closed storage with and without ventilation. Steam exploded bark was collected directly from a pilot scale steam explosion plant, and before and after subsequent pelletizing. Storage and active sampling of VOCs in the headspace was done in a bench-scale set-up using Tenax-TA absorbent. The impact of storage time and ventilation to reduce VOCs was evaluated through multivariate statistical analysis. The results showed that VOC concentrations in the headspace were reduced by increased storage time, and that heavier VOCs reduced faster. No impact on either reducing or shifting VOC composition could be achieved by controlled ventilation during storage; instead, VOCs emitted to the same concentrations anew, independent of process step, storage time, or number of ventilations.

  • 244.
    Borén, Eleonora
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Larsson, Sylvia H.
    Thyrel, Mikael
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Averheim, Andreas
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    VOC off-gassing from pelletized steam exploded softwood bark: emissions at different industrial process stepsIn: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188Article in journal (Refereed)
    Abstract [en]

    Formation of hazardous gases during transport and storage of biomass for large-scale bioenergy production is an important safety concern. While off-gassing has been addressed in numerous studies for raw woody biomass, very few describe it in the context of biomass for bioenergy production pre-treated by thermal technologies such as steam explosion. Volatile Organic Components (VOCs) are expected to be altered by the treatment, but until now there is no research published on VOC profiles of steam exploded materials in industrial scale. In the present study, VOCs emitted from the products were evaluated by sampling from different production steps from steam explosion of softwood bark, and following the production chain including also pelletization. Off-gasses were actively sampled using Tenax TA absorbent and analyzed by GC-MS. The VOC formation dependency of operation and storage conditions at different process steps was evaluated by multivariate statistical analysis. We showed that the different process steps along the production line was the main influencing factor for VOC off-gassing amounts, with highest VOC levels directly after the steam explosion process. Treatment severity mainly altered the relative composition of VOC profiles with more terpenes emitted from milder treatment, whereas more severe treatment shifted VOCs composition to contain more furans, e.g. furfural. In summary, treatment by steam explosion leads to potentially problematic VOC off-gassing profiles from the material, and levels vary considerable along the production line. The findings are important from a fuel handling and working environment perspective.

  • 245.
    Borén, Eleonora
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University Industrial Doctoral School for Research and Innovation, Sweden.
    Larsson, Sylvia H.
    Thyrel, Mikael
    Averheim, Andreas
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    VOC off-gassing from pelletized steam exploded softwood bark: emissions at different industrial process steps2018In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 171, p. 70-77Article in journal (Refereed)
    Abstract [en]

    Formation of hazardous gases during transport and storage of biomass for large-scale bioenergy production is an important safety concern. While off-gassing has been addressed in numerous studies for raw woody biomass, very few describe it in the context of biomass for bioenergy production pre-treated by thermal technologies such as steam explosion. Volatile Organic Components (VOCs) are expected to be altered by the treatment, but until now there is no research published on VOC profiles of steam exploded materials in industrial scale. In the present study, VOCs emitted from the products were evaluated by sampling from different production steps from steam explosion of softwood bark, and following the production chain including also pelletization. Off-gasses were actively sampled using Tenax TA absorbent and analyzed by GC–MS. The VOC formation dependency of operation and storage conditions at different process steps was evaluated by multivariate statistical analysis. We showed that the different process steps along the production line was the main influencing factor for VOC off-gassing amounts, with highest VOC levels directly after the steam explosion process. Treatment severity mainly altered the relative composition of VOC profiles with more terpenes emitted from milder treatment, whereas more severe treatment shifted VOCs composition to contain more furans, e.g. furfural. In summary, treatment by steam explosion leads to potentially problematic VOC off-gassing profiles from the material, and levels vary considerable along the production line. The findings are important from a fuel handling and working environment perspective.

  • 246.
    Borén, Eleonora
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Rudolfsson, Magnus
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Pommer, Linda
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Larsson, Sylvia H.
    Off-gassing from 16 pilot-scale produced pellets assortments of torrefied pine: impact of torrefaction severity, storage time, pelletization parameters, and pellet qualityManuscript (preprint) (Other academic)
    Abstract [en]

    Off-gassing from wood pellets poses risks in large scale handling chains - yet little is known on off-gassing from pellets of torrefied wood. This study reports CO, CO2, and O2 concentrations in off-gases during storage of 16 torrefied and two untreated pellets assortments. According to an experimental design, pellets were produced in pilot scale from pine chips torrefied at five different set points. Off-gassing was assessed in relation to storage conditions, torrefaction and pelletization parameters, and pellet quality. Pellets from the most severely torrefied pine formed CO, CO2, and consumed O2 similarly to untreated pellets. Off-gassing was positively correlated to pellet moisture content; however, the most severely torrefied also retained the least moisture. Open air storage (20–270 days) of torrefied chips prior to pelletization did not affect off-gassing levels. Results are important for safe handling; torrefied pellets can cause comparable levels as untreated pellets of CO, CO2, and O2.

  • 247.
    Borén, Eleonora
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Rudolfsson, Magnus
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Pommer, Linda
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Larsson, Sylvia H.
    Off-gassing from pilot-scale torrefied pine wood chips: – impact of torrefaction severity, cooling technology, and storage timeManuscript (preprint) (Other academic)
    Abstract [en]

    During handling and storage of conventional wood-based energy carriers, O2 depletion as well as CO and CO2 off-gassing can reach hazardous levels, and certain irritating VOCs trespass exposure levels. When new thermally pre-treated biomass commodities are entering consumer markets, knowledge on these assortments’ off-gassing behaviour is needed. In this study, relative concentrations of VOCs, CO, CO2, and O2 in off-gases of five different pilot-scale torrefied pine wood chip assortments was monitored over 12 days. VOC composition shifted with increased torrefaction treatment; terpene concentrations decreased while furan and lignin derivates increased. Generally, VOC amounts decreased with storage time, but for the least severely torrefied chips (291°C, 6 min), certain VOCs increased; e.g. hexanal, acetone, and 2-pentylfuran. Torrefied chips was subject to two different cooling technologies: i) heat exchanging and ii) additional water spraying. Water spraying resulted in higher VOC concentrations, stronger O2 depletion, and higher CO2 by a factor four. 

  • 248.
    Borén, Eleonora
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University Industrial Doctoral School for Research and Innovation.
    Yazdanpanah, Fahimeh
    Lindahl, Roger
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Schilling, Christoph
    Chandra, Richard P.
    Ghiasi, Bahman
    Tang, Yong
    Sokhansanj, Shahabaddine
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Larsson, Sylvia H.
    Off-gassing of VOCs and permanent gases during storage of torrefied and steam exploded wood2017In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 31, no 10, p. 10954-10965Article in journal (Refereed)
    Abstract [en]

    Thermal treatment for upgrading of low-value feedstocks to improve fuel properties has gained large industrial interest in recent years. From a storage and transport perspective, hazardous off-gassing could be expected to decrease through the degradation of reactive biomass components. However, thermal treatment could also shift chemical compositions of volatile organic components, VOCs. While technologies are approaching commercialization, off-gassing behavior of the products, especially in terms of VOCs, is still unknown. In the present study, we measured off-gassing of VOCs together with CO, CO2, CH4, and O2 depletion from torrefied and steam exploded softwood during closed storage. The storage temperature, head space gas (air and N2), and storage time were varied. VOCs were monitored with a newly developed protocol based on active sampling with Tenax TA absorbent analyzed by thermal desorption-GC/MS. High VOC levels were found for both untreated and steam exploded softwood, but with a complete shift in composition from terpenes dominating the storage gas for untreated wood samples to an abundance of furfural in the headspace of steam exploded wood. Torrefied material emitted low levels of VOCs. By using multivariate statistics, it was shown that for both treatment methods and within the ranges tested, VOC off-gassing was affected first by the storage temperature and second by increasing treatment severity. Both steam exploded and torrefied biomass formed lower levels of CO than the reference biomass, but steam explosion caused a more severe O2 depletion.

  • 249.
    Bostedt, Nicklas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    NGN - Nästa Generations Nätverk (Krav och Målbild) för Piteå kommun2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    My work has been to develop a basis for Piteå Municipality's future investment on a newer and more modern IT-infrastructure. The report describes primarily the areas surrounding network segmentation, a new flexible WAN solution and a central policy engine with IEEE 802.1x. Through these implementations achieved a dynamic role-based access, a tool that all big organizations should have to tackle the challenges that have arisen over the last few years with BYOD (Bring Your Own Device).

    In order to achieve a more dynamic and segmented network, I have separated from layer 2 using MCE and L3VPN transport to various municipal sites, while I logically divided the network into different zones. Network optimization is today largely based on moving the intelligence from hardware to software, a so-called SDN (Software Defined Network). I have therefore chosen in this report to place great emphasis on describing the features of HP IMC, where new opportunities for control, management and logging of the network are presented and how they can optimize the operation of an organization.

    This work is a continuation of NGN – Nästa Generations Nätverk (Nätverks- och Riskanalys) för Piteå Kommun by Johan Carls.

  • 250.
    Boström, Dan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lindström, Erika
    Boman, Christoffer
    Backman, Rainer
    Öhman, Marcus
    Grimm, Alejandro
    Ash transformation chemisty during energy conversion of agricultural biomass2009In: International Conference on Solid Biofuels, ICSB2009, Beijing, China, 2009Conference paper (Other academic)
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