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  • 101.
    Bergqvist, Bengt
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Maskinkörkort i gymnasieskolan?2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna rapport undersöker hur yrkeslärare på gymnasieskolor inom hantverk/finsnickeri ser på maskinkörkort som från 2012 är nytt i Sverige, och vad yrkeslärarna anser runt den webbaserade utbildningsformen.

    Träindustrin är hårt drabbad av olyckor som ger lång sjukfrånvaro och bestående men.

    Flera projekt har sedan 1980-talet genomförts för att undersöka arbetsmiljön inom träbranschen. Men dessa insatser har inte räckt för att minska arbetsskadorna tillräckligt.

    Det har visat sig att det Danska maskinkörkortet har haft positiv inverkan på olycksstatistiken i Danmark.

    Genom enkäter har information samlats in från yrkeslärare som genomgått testledarkurs för det Svenska maskinkörkortet.

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  • 102.
    Bergström, Mikael
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, Institutionen för industriella produktionssystem.
    Blom, Åsa
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Differences in properties between Norway spruce (Picea abies) heartwood and sapwood. Part 1. Accelerated durability testing2007In: Proceedings of the Wood protection Conference: organized by the Forest Products Society, 2007Conference paper (Other academic)
  • 103.
    Bergström, Nicklas
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Förvaltning av kommunägda skogar i Uppsala län2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta är en intervjustudie om skoglig förvaltning inom Uppsala läns kommuner med fokus på planering, skötsel, kompetens, upphandling och uppföljning. Studien visar att det saknas bra planeringsverktyg och de som finns används generellt passivt, skötseln i den tätortsnära skogen är anpassad, den formella skogliga kompetensen är låg, upphandling sker som ramavtal och direkt-upphandling samt utlämnad entreprenad följs upp i någon form.

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    Förvaltning av kommunägda skogar
  • 104.
    Berling, Peter
    et al.
    Linnaeus University, Faculty of Business, Economics and Design, Linnaeus School of Business and Economics.
    Farvid, Mojtaba
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Ledtidsbestämning i distributionssystem: [ Lead-time determination in distribution systems ]2011In: Plans forsknings- och tillämpningskonferens 2011: logistik i praktisk tillämpning, Stockholm: Logistikföreningen , 2011, p. 205-216Conference paper (Refereed)
    Abstract [sv]

    I den här artikeln presenterar vi en lösning på problemet att skatta ledtiden förväntade värde och variation i ett distributionssystem. Det är ett väsentligt problem att lösa då en snabb och korrekt skattning av ledtiden är ett måste för att kunna dimensionera säkerhetslager rätt. Nyare forskning indikerar dessutom att man skall ha en förhållandevis låg servicenivå uppe på en centrallagernivå vilket accentuerar problemet då ledtiden då blir längre och mer osäker på lägre nivåer i försörjningskedjan. Detta då centrallagret oftare får brist vilket leder till mer frekventa och långvariga förseningar av utleveranserna.

    Vi angriper problemet med hjälp av matematiskt modellering varvid vi tar fram slutna uttryck för att beräkna väntevärdet så väl som variansen av förseningen ut från centrallagret. Denna metod utvärderas med hjälp av simuleringsstudier vilka indikerar på en god överenstämmelse med verkligheten.

  • 105. Bianchi, S
    et al.
    Placencia Peña, M.I
    Ganne-Chédeville, C
    Pichelin, F
    Sandberg, Dick
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Softwood strand-boards manufacturing without adhesive using linear friction welding technology2012In: Current and Future Trends of Thermo-Hydro-Mechanical Modification of Wood., Nancy University , 2012, p. 142-143Conference paper (Refereed)
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  • 106.
    Blennow, Kristina
    et al.
    Sveriges Lantbruksuniversitet (SLU).
    Andersson, Mikael
    Sallnäs, Ola
    Olofsson, Erika
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Climate change and the probability of wind damage in two Swedish forests2010In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 259, p. 818-830Article in journal (Refereed)
    Abstract [en]

    We simulated how possible changes in wind and ground-frost climate and state of the forest due to changes in the future climate may affect the probability of exceeding critical wind speeds expected to cause wind damage within one northern and one southern study area in Sweden, respectively. The topography of the study areas was relatively gentle and the forests were dominated by Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.). Using estimated changes in the net primary production (NPP) due to climate change and assuming a relative change in the site productivity equal to a relative change in NPP, we simulated possible future states of the forest under gradual adjustment of the site index in response to climate change using the model The Forest Time Machine. Global climate change scenarios based on two emission scenarios and one general circulation model were downscaled to the regional level. The modified WINDA model was used to calculate the sensitivity of the forest to wind and the probability of wind damage for individual forest stands for the periods 2011–2041 and 2071–2100 and for a control period 1961–1990. This was done while taking into account effects on stability of the forest from expected changes in the occurrence of ground frost. Increasing sensitivity of the forest to wind was indicated for both study areas when adhering to recommended management rules of today. Adding also a changed wind climate further increased the probability of wind damage. Calculated probabilities of wind damage were generally higher in the southern study area than in the northern one and were explained by differences in wind climate and the state of the forests, for example with respect to tree species composition. The indicated increase in sensitivity of the forest to wind under the current management regime, and possibly increasing windiness, motivate further analysis of the effects of different management options on the probability of wind damage and what modifications of Swedish forest management are possibly warranted.

  • 107.
    Blom, Åsa
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Svenskt barrvirke: Beständighet och fuktegenskaper ovan mark.2006Report (Other academic)
  • 108.
    Blom, Åsa
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Bergström, Mikael
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Mycologg – a new accelerated test method for wood durability above ground.2005In: Wood Science and Technology, Vol. 39, p. 663-673Article in journal (Refereed)
  • 109.
    Blom, Åsa
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Bergström, Mikael
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Untreated Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) wood-panels exposed out of ground contact in Sweden for two years.2005In: Holz als Roh- und Werkstoff, Vol. 64, p. 53-61Article in journal (Refereed)
  • 110.
    Blom, Åsa
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Johansson, Jimmy
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sivrikaya, Hüseyin
    Some factors influencing susceptibility to discoloring fungi and water uptake of Scots pine (Pinus sylvestris), Norway spruce (Picea abies) and Oriental spruce (Picea orientalis) 2012In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 8, no 2, p. 139-144Article in journal (Refereed)
    Abstract [en]

    The heartwood and sapwood from Scots pine (PS), Norway spruce (PA), and Oriental spruce (PO) were tested for susceptibility to discoloring fungi and water uptake. In addition, annual ring width and density were measured. The methods used were Mycologg for testing growth of fungi and a modified version of EN 927-5 to investigate water uptake. For pine, the heartwood showed a lower water uptake and no discoloring fungi growing in the tests. The heartwood had a significantly higher density and smaller annual ring width than the sapwood. In PA the heartwood had significantly lower discoloration than sapwood. The total water uptake in g/m2 was significantly higher in sapwood, but not the calculated moisture content. As for wood properties, the density was significantly higher in sapwood compared to heartwood, although there were no differences in annual ring width. Regarding PO, differences in water uptake could be seen between sapwood and heartwood although the densities were similar. These results show that susceptibility to discoloring fungi and water uptake is hard to correlate to a single inherent property when looking at different wood species.

  • 111.
    Blom, Åsa
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Thörnqvist, Thomas
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Bergström, Mikael
    Outdoor exposure of untreated Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies L. Karst) wood samples2010In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 5, no 3-4, p. 204-210Article in journal (Refereed)
    Abstract [en]

    Untreated Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) samples were exposed above ground in a durability test for six years. The samples consisted of three pieces of wood, 22x95x500 mm, screwed together; two pieces lengthwise with a third piece overlapping. Weight was measured, to calculate moisture content (MC), and samples checked regularly for cracks and fungal growth. Parameters investigated were heartwood/sapwood (pine), annual ring orientation (spruce), stand site, annual ring width and density.

    Stand site, annual ring width or density had no influence on MC or fungal growth for neither pine nor spruce. Spruce samples with vertical annual rings had lesser amounts of cracks than samples with horizontal annual rings.

    Regarding pine sapwood samples, they showed high MC and large amount of rot fungi, while heartwood had lower MC and no rot. Most spruce samples were similar to pine heartwood, except from a few samples that had high MC and fungal growth. Those were all sawn from the outer part of the log. Therefore, it can be stated that spruce sawn from the inner part has almost the same properties as pine heartwood while spruce from the outer part of the log has properties similar to pine sapwood.

  • 112.
    Blom, Åsa
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Thörnqvist, Thomas
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Bergström, Mikael
    Presence of longitudinal cracks in planks from storm-felled pine (Pinus sylvestris L.) and spruce (Picea abies (L.) Karst.)2012In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 7, no 4, p. 237-241Article in journal (Refereed)
    Abstract [en]

    After the severe storm Gudrun in southern Sweden in 2005, a quantitative study was done in order to investigate the presence of lengthwise crack on planks taken from storm-felled trees in southern Sweden, compared to planks from standing trees not subjected to this storm (central Sweden). The main yield from each log was examined. In total, 1087 pine (Pinus sylvestris) planks and 3626 spruce (Picea abies) planks from the storm-struck area were investigated and compared to 1953 spruce and 2000 pine planks from trees outside the storm-struck area. The examination of cracks was done visually on dried planks. For pine, 51.7% of the planks from storm-felled trees had a total length longer than 0.5 m, compared to 7.3% for the reference material. As for spruce, 11.0% of the planks from storm-felled trees had a total crack length of more than 0.5 m, compared to the reference material where 2.2% had cracks longer than 0.5 m. The results show that the storm-felled trees had more longitudinal cracks than the reference material and that pine was more likely to develop storm-related cracks than spruce.

  • 113.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Johansson, Jimmy
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sandberg, Dick
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Contact free measurement of complex shapes in the wood industry2011In: Mechano-chemical transformations of wood during THM processing / [ed] Parviz Navi and Andreas Roth, Biel, Switzerland: Bern University of Applied Sciencs, Architecture, Wood and Civil Engineering , 2011, p. 143-144Conference paper (Refereed)
    Abstract [en]

    There is an increasing need to update and correct information about product geometry in the wood manufacturing industry. Changes in machinery or personnel can be the cause of that need. Manual measurement takes time and diff erent ways of digitizing the geometry of the products have therefore been developed.

    In this study, two methods (3D-coordinate measurement and optical scanning) have been tested together in order to determine the position of a product in relation to the processing machine, and to optically scan the product geometry. The aim was to identify and evaluate methods to digitize product geometry into a CAD-model for the wood industry. Th e seat shell measured was fitted in the CNC-machine where the processing later would be performed.

    The methodology used has made it possible to create a CAD-model from the physical model. Based on the experience from this methodology, it would be recommended to continue by creating of a tool that minimizes the need for after processing, i.e. the adjustment of certain coordinates manually.

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  • 114.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Johansson, Jimmy
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sandberg, Dick
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Improving the performance of bended laminated veneer products2011In: Mechano-chemical transformations of wood during THM processing / [ed] Parviz Navi and Andreas Roth, Biel, Switzerland: Bern University of Applied Sciencs, Architecture, Wood and Civil Engineering , 2011, p. 147-148Conference paper (Refereed)
    Abstract [en]

    Laminated bending of veneers mean that dried, thin veneers or thin wood sheets are glued together under influence of pressure and eventually increased temperature. At the same time the product is given its desired shape, most often curved. This thermo hydro mechanical process offers several benefits. For example thick bends of small radiuses of any species of wood may be formed and poor quality wood containing knots, splits and other defects may be utilised. Laminated bends can usually be set more readily and made to conform better to the shape of the form than similar bends of solid wood. Further no softening treatment is generally required before the pieces are bent. However, there are also disadvantages e.g. more technical skill and better equipment are usually required than for solid wood bending. The presence of glue may be somewhat detrimental to the machines used for the final cleaning up of the bent pieces. Further the glue lines which are usually visible on the sides may be an aesthetical unappreciated effect [1],[2].The quality of the laminated bended veneer products are obtained as an interaction between the process, the veneers and the glue [3]. In industries designing and producing these products it is of interest to obtain better understanding of how processing- and material parameters affect the product quality. With an improved understanding of the material and processing parameters it may be possible to increase the efficiency of wood utilisation and promote the development of new processes and products that manipulate the viscoelastic nature of wood. In particular the possibilities to obtain narrower radius of curvature and better possibilities of bending in more than one plane would be advantageous.This study has focused on the moisture content (MC) and the grain angle orientation in the veneers. These two specific aspects were assumed to have a great influence on spring-back and distortions of the laminated bended veneer products. Spring-back and distortions were therefore studied in separate tests where MC and the grain angle orientation was varied separately in manufactured laminated bended wood products. After manufacturing the products were exposed to variations in humidity and temperature whereupon the spring-back and distortions were measuredThree tests were performed. For the first and the second test a seat shell was selected as test product, figure 1a. To the third test another product was selected, figure 1b. This product was a small bookshelf. The company producing this shelf had experienced large problems considering distortions of this product. Further the product was very simple in shape with only one bend and therefore suitable for measurements.In the first test the influence of MC of the veneers was investigated. In the second and third test the influence of grain angle of the veneers was studied.For the study veneers of birch and beech were selected in the production. For the first and third study only birch veneers were used. The veneers were initially conditioned to equilibrium moisture contents (EMC) according to setups in different test groups. For the first study a test group was also built up from veneers taken directly out of production to study the industrial conditions. The seat shells in this test group contained veneers conditioned to EMC 4 %, except for the surface veneers that had been stored in the production hall. The humidity and temperature conditions in this room corresponded to MC 7 %.The manufacturing of the products were performed in industrial conditions. In the tests the products were built up from a number of veneers and the studied factors were varied between the veneers in a controlled manner.The results from the first test showed that the MC of the veneers influenced the spring-back and the distortions. A large moisture gradient between veneers and especially unsymmetrical placements of these in the construction were especially critical. The results from the second and third tests showed that grain angle deviation has large effect on the distortions of the products. Even a small grain angle deviation as in study two (5°) resulted in large problems with distortions. The study also showed that when crossing two or more veneers with deviating grain angles there were cases when these faults interacted and multiplied the distortions. In production grain angle deviations can be a result of inaccurate placement of the veneers during pressing, incorrect cutting of the veneers, inherent from the growth of the tree or a combination of these factors. Deviations of the grain angle were, however, shown to have only small effects on spring-back.

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  • 115.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Johansson, Jimmy
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sandberg, Dick
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Kifetew, Girma
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    The influence of individual veneer orientation on the shape stability of planar lamination2012In: Current and Future Trends of Thermo-Hydro-Mechanical Modification of Wood. Opportunities for new markets? / [ed] Mathieu Pétrissans and Philippe Gérardin, Nancy, France, 2012, p. 160-162Conference paper (Refereed)
  • 116.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Rowell, Roger
    University of Wisconsin-Madison.
    Bio-based adhesives at laminated veneers2012In: Proceedings of the 8th meeting of the Northern European Network for Wood Science and Engineering (WSE) / [ed] Antanas Baltrušaitis and Kristina Ukvalbergiené, Kaunas, Lithuania, 2012, p. 221-225Conference paper (Refereed)
  • 117.
    Blyberg, Louise
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Timber/Glass Adhesive Bonds for Structural Applications2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Timber with its natural appearance and glass with its transparency may be appealing material for architects and users of modern buildings. Glass is a brittle material, but it is about six times stiffer than timber. Combined appropriately, the materials could form different types of composite products, e.g. beams or shear walls, that can be included in the load-carrying structure of buildings. e knowledge on load- carrying timber/glass components is limited. e intention of this research has been to contribute to the knowledge required for the industry to be willing to produce timber/glass components for the market.

    The thesis includes experimental testing accompanied with complementary nite element simulations, which provide more details and information about the test results. Tests were performed on small-scale specimens with a bond area of 800 mm2 as well as on I-beam and shear wall prototypes. For the small-scale specimens tested in standard climate, three different adhesives were used for the bond line between timber and glass. ese specimens were tested in both tension and shear. In addition, one of the adhesives was used for small-scale shear specimens which were exposed to different humidity levels before the tests were performed. e 4 m long I-beam prototypes designed with a web of glass and wooden anges were tested in four- point bending. e shear wall prototypes were tested by applying either a vertical load, a horizontal load or a combination of these, all being applied in the plane of the shear wall.

    Of the three adhesives used in the small-scale testing, an acrylate adhesive had the largest strength, both in tension and in shear. e study on the effect of humidity was performed with this adhesive. is study indicates that the adhesive properties do not change dramatically in indoor climate. is adhesive was also used for twelve of the fourteen tested I-beams. e results from the beams show that a signi cant redundancy is obtained; the load at the nal failure was around 240 % of the load when the rst crack in the glass web appeared. e shear walls were glued using the acrylate adhesive and for a few cases a 2-component silicone based adhesive. e results from the shear wall tests showed the shear wall to behave in a much more brittle manner, without any noticeable redundancy.

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  • 118.
    Blyberg, Louise
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Serrano, Erik
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Timber/Glass adhesively bonded I-beams2011In: Glass Performance Days, Conference Proceedings, 2011, 2011, p. 451-456Conference paper (Other academic)
    Abstract [en]

    Timber and glass are materials with aesthetically pleasing properties. If the materials can be combined appropriately, drawbacks can be overcome and the beneficial mechanical properties utilised and timber/glass elements can be a natural part of the load-carrying structure of buildings. Since glass is a brittle material, an important task for the timber is to provide redundancy – a glass failure should not lead to a catastrophic failure of the entire structural element.

    This paper presents results from ongoing research related to load-bearing components made of timber and glass. Results from tests on small timber/glass bond-line specimens, recently submitted for publication, are briefly presented. The core of the paper is, however, a study of fourpoint bending tests on twelve timber/glass I-beams with acrylate adhesive. These I-beams had a nominal height of 240 mm and were designed with a web of 10 mm float glass and flanges of LVL (laminated veneer lumber), bonded together with an acrylate adhesive.

    The mean values of the beams imply that the ultimate load capacity is 240 % of the load when the fi rst crack in the glass appeared. Thus, the timber well fulfils the redundancy task of avoiding a catastrophic failure of the structural element.

  • 119.
    Blyberg, Louise
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Serrano, Erik
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Bertil, Enquist
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sterley, Magdalena
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Adhesive joints for timber/glass applications: Part 1: Mechanichal properties in shear and tension.Manuscript (preprint) (Other academic)
  • 120.
    Blyberg, Louise
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Serrano, Erik
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Enquist, Bertil
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sterely, Magdalena
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Adhesive joints for timber/glass applications: Part 2: Test evaluation based on FE-analyses and contact free deformation measurements.Manuscript (preprint) (Other academic)
  • 121.
    Blyberg, Louise
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Serrano, Erik
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Enquist, Bertil
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sterley, Magdalena
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Adhesive joints for structural timber/glass applications: Experimental testing and evaluation methods2012In: International Journal of Adhesion and Adhesives, ISSN 0143-7496, E-ISSN 1879-0127, Vol. 35, p. 76-87Article in journal (Refereed)
    Abstract [en]

    A study of three different adhesives, silicone, acrylate and polyurethane, intended for adhesive joints in structural timber/glass applications is presented in this paper. Intentionally, adhesives with a wide range of properties were chosen. The adhesive bonds between timber and glass were tested both in tension and in shear with a bond area of 800 mm2. Special fixtures were designed both for gluing and testing the specimens. The results include strength and failure type of the adhesive bond as well as deformation of the bond lines, measured with LVDTs and a non-contact optical 3D-deformation measuring system used in combination with finite element modelling in order to obtain detailed information about the behaviour.

    Of the tested adhesives, the acrylate (SikaFast 5215) provided the largest strength, both in tension and shear. The mean strength obtained for this adhesive bond was 3.0 MPa in tension and 4.5 MPa in shear.

    Further, it is demonstrated how rotations in the specimen during the test can be detected with the optical measuring system and how finite element modelling can be used to study the stress distribution internally in the adhesive bond. One conclusion obtained from the combination of results from the optical measuring system and finite element modelling is that the behaviour of the silicone adhesive is highly influenced by its near incompressible behaviour.

  • 122.
    Blyberg, Louise
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Serrano, Erik
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Enquist, Bertil
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sterley, Magdalena
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Timber/Glass Adhesive Bonds: Experimental testing and evaluation methods2010Report (Other academic)
    Abstract [en]

    Both timber and glass are materials that have aesthetically pleasing properties. An appealing idea is to combine them to overcome the drawbacks and utilise the beneficial mechanical properties. Adhesive bonding with an appropriate adhesive could provide a uniform stress distribution at the transition between the materials.

    This report presents a study of three different adhesives, silicone, acrylate and polyurethane. Intentionally, adhesives with a wide range of properties were chosen. The adhesive bonds between timber and glass were tested both in tension and in shear with rather small bonds, 800 mm2. Special fixtures were designed both for gluing and testing of the adhesive bond specimens studied. The results presented include a traditional study of strength, failure type and relative displacement measured with LVDT’s, but also an extended study with a non-contact optical 3D-deformation measuring system and finite element modelling.

    Of the adhesives tested, the acrylate (SikaFast 5215) performed best, both in tension and shear. The mean strength obtained for this adhesive was 3.0 MPa in tension and 4.5 MPa in shear. Even if an important factor when gluing glass is the load distribution ability, the flexible silicone adhesive has too low stiffness and strength for use in structural components, where structural refers to the ability of a component to carry loads other than its own weight.

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  • 123.
    Boje, Lis
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Hannerz, Mats
    Löf, Magnus
    Southern Swedish Forest Research Centre, SLU.
    The role of internet in knowledge-building among private forest owners in Sweden2010In: Broadleaved forests in southern Sweden: Management for multiple goals / [ed] Magnus Löf, Jörg Brunet, Leif Mattsson, Mats Nylinder, Wiley-Blackwell, 2010, p. 225-234Chapter in book (Other academic)
    Abstract [en]

    The major part of the temperate broadleaved forests in Sweden is owned by non-industrial private forest owners. The daily decisions on management of these forests therefore rely on a diverse owner population with various experience, age, education and attitudes. This study investigated how the forest owners obtain their information needed for their decisions. The use of internet as an information channel was specifically focused. Analyses were made of a postal questionnaire with responses from 327 private forest owners in southern Sweden. The respondents were sorted into groups of different age, education, gender, property size and residency (living on or off the property). For all groups, personal advisory was the most important channel for knowledge-building, followed by forest magazines and newsletters from forest organizations. Meetings and courses were also considered important, while internet had a lower rank. Still, 29% of all respondents considered internet as an important channel for knowledge-building in silviculture. Three-quarters of the respondents had internet access in their homes, and 40% used internet daily. Internet was used for forestry purposes at least monthly by 30% of the respondents. Age and education had a significant influence on the scored importance of internet as a communication channel for forest information, with younger forest owners (

    50 yr) and owners with a university degree being the most devoted internet users. Owners >65 yr and owners with only primary school education were much less inclined to rely on internet for their information needs.

     

  • 124.
    Boklund, Jockum
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Aagesson, Conny
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Vilka behov har och hur upplever näringslivet samarbetet med skolan vid lärlings- och APL-verksamhet i Värnamo- och Tingsryds- regionerna   What are the needs and how does the business federation experience cooperation with the school at the apprenticeship and APL activity in Värnamo and Tingsryd regions2011Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract (in English) The report clarifies how the economy of Värnamo and Tingsryd area experiencing and implementing APL, it also reveals their need for jacking from the school to improve students achievement.

    By highlighting some of the requirements, expectations, obligations and rights as schools, businesses and students have between each other can enhance our understanding of each other's activities. With increased understanding of each other's needs, function and values can be a more seamless cooperation take place which can increase the efficiency, usefulness and effectiveness of APL and apprenticeship.

    The investigation of the report includes a survey of 25 questions that companies involved in APL answers and interviews by two well-designate individuals in the subject, Jonas Olofsson, who among other things, wrote the book "Krisen i skolan" and Annika Jervgren is research assistant in the National Apprentice Committee.

    The supervisor's actions during the APL are addressed and they are critical to student achievement and how the profession is perceived. It is also evident that there is a desire for increased communication between schools and businesses and that practice is governed by established documented procedures to make the workplace time will be as constructive as possible for the students.

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    fulltext
  • 125.
    Bollvik, Mikael
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Svensson, Pontus
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Dagvattenhantering på Arenastaden i Växjö2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Rapporten behandlar projekteringen och genomförandet kring det lokala omhändertagandet av dagvatten för de fyra nybyggda arenorna på Arenastaden i Växjö. Granskningen behandlar framförallt underjordiska fördröjningsmagasin men även alternativa lösningar.

    Arbetet har genomförts med hjälp av intervjuer och studier kring olika lösningar för lokalt omhändertagande av dagvatten.

    Förändringsförslagen som presenteras bottnar i mer tid för projektering, förbättrad kommunikation och större användande av mer genomsläppliga ytor.

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    Dagvattenhantering på Arenastaden i Växjö
  • 126.
    Bolmsvik, Åsa
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Ekevid, Torbjörn
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    FE modeling of wooden building assemblies2010In: InterNoise 2010-Lisbon Portugal 13-16 June, 2010, p. 1-10Conference paper (Refereed)
    Abstract [en]

    Residential timber framed buildings have in some cases received complaints from inhabitants due to structure-borne sound at low frequencies, even if the building meets the regulations with respect to impact sound quality. This paper describes FE-analyses to evaluate the test setups of a building assembly and to prepare for the full-scale experimental modal analysis planned. By modal analysis, the dynamic properties of a structure, such as eigen modes and damping characteristics, can be extracted.

     

    The test assembly consists of prefabricated wall and floor/roof timber elements. Different assembly and joining methods as well as building element are used. The eigen modes and damping differs between the assemblies investigated which influence the dynamic response in the lower frequencies. The results are carefully evaluated and planned measurements are discussed.

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    fulltext
  • 127.
    Bolmsvik, Åsa
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Linderholt, Andreas
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jarnerö, Kirsi
    SP Wood Technology, SP Technical Research Institute of Sweden.
    FE modeling of a lightweight structure with different junctions2012In: Euronoise 2012-proceedings / [ed] Czech Acoustical Society, European Acoustics Association (EAA), 2012, p. 162-167Conference paper (Refereed)
    Abstract [en]

    In lightweight structures it is common to use damping material in junctions to decrease sound transmission. In field measurements, the damping properties of the structure are easily overestimated due to the omnipresent energy losses to the surroundings. Thus, reliable estimates of structural properties cannot be guaranteed.

    Vibrational tests were done on a full scale wooden construction, consisting of a floor and supporting beams, representing walls, to investigate the effect of different junctions. Totally seven different setups were made using the same building components. In one setup the floor and the walls were screwed together, in five setups different elastomers was positioned between the floor and the walls and in the last setup the floor was resting free on top of the walls. A shaker, with pseudorandom excitation, was used for the excitation of the structure and accelerometers were used for response measurements. The effect of the junction was investigated by studying the acceleration levels in the edge part of the floor-wall junction in different directions.

    Modal data, extracted from test data using experimental modal analysis, form input and validation data for the following finite element (FE) analysis. Two FE models; modeling one elastomer and the screwed setup, are used for the studies.

    The aim was to study if the eigenmodes rendering the acceleration levels are similar in test and in analysis, using common material properties.

    The results from correlation between test and analytical results show that the material properties of the wood need to be known better; more sophisticated models are needed to fully simulate the dynamic behavior of the structure. Anyhow, with the used properties the mode shapes are captured fairly well in the lower frequencies. Furthermore, the experiment shows that the damping properties of the junction material have a major influence on the behavior of the structure.

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    fulltext
  • 128.
    Bolmö, Catharina
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Hur gick det?En studie om gymnasiesärskolans elever efter avslutad skolgång2010Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
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    FULLTEXT01
  • 129.
    Bonarski, Jan T.
    et al.
    Polish Academy of Sciences.
    Olek, Wiesław
    Poznań University of Life Sciences.
    Pospiech, Jan
    Polish Academy of Sciences.
    Kifetew, Girma
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Application of spatial distribution of cellulose crystallites for determining wood anisotropy2012In: Workshop micro-characterisation of wood materials and properties: 24–26 October, 2012 Edinburgh, Scotland, UK, 2012, p. 29-30Conference paper (Refereed)
    Abstract [en]

    The anisotropy of wood properties is related to the ultrastructural organization of wood cell walls. The mean microfibril angle (MFA) is the most obvious parameter quantifying the ultrastructure. Various methods for the MFA measurements have been developed. However, the direct microscopic techniques (both light and electron ones) as well as the indirect X-ray methods were dominating. However, the helical arrangement of cellulose fibrils in wood cells around the longitudinal anatomical direction results in spatial changes of orientations of the lattice planes. Such misorientation between the longitudinal anatomical direction and the microfibril axes has a spatial character and therefore, it can not be correctly described by a single parameter only, i.e. by MFA. The most comprehensive description of the spatial distribution of orientations of cellulose crystallites can be obtained when defining a set of parameters consisting of the rotating axis (given by the polar coordinates θ and ψ and referred to the sample framework) as well as the angle of rotation (ω) around the axis. In order to analyze of wood anisotropy a stereographic projection of the rotating axes on the base of the (010) plane of the lattice cell of cellulose is recommended. Regarding the crystallographic system of the monoclinic lattice of cellulose and the two-fold symmetry of the <010> axis, the projection plane corresponded to the a-c plane of the elementary cell [3]. An example of the projection and the distribution of the rotation axis characterizing the spatial organization of wood microfibrils is given in Fig. 1. The θ, ψ and ω parameters were determined with the original computer program SpaceWood. The parameters were determined regarding the crystallographic symmetry and the parameters of the unit-cell of cellulose given by Zugenmaier [3].

  • 130.
    Borislavov, Biser
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Borisov, Ivaylo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Panchev, Vilislav
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Design of a Planetary-Cyclo-Drive Speed Reducer: Cycloid Stage, Geometry, Element Analyses2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project has been assigned by SwePart Transmissions AB. It is about calculation and dimensioning, of the elements in a cycloid stage of a speed reducer. Their idea is to use the results from this project and go into production of such reducer to cover another segment of the market. The company is interested in supplying transmissions for robust systems and for various industrial purposes, where large ratios of speed reduction are needed.

    The company has given the necessary input data for the model. They have also provided a real cyclo-drive reducer for further analyses. To obtain the dimensions and forming the geometry of the gears, some parts of Professor Ognyan Alipiev’s Phd work have been used. Professor Alipiev is head of “Theory of Mechanisms and Machines” department in University of Ruse “Angel Kunchev”, Bulgaria.

    For the determination of forces on the elements, models and drawings has been used Solidworks (SW) CAD software and SW simulation environment. The resultant calculation process can be used for designing the geometry and determination of the properties regarding the cycloid reducer.  

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    Cycloid Stage
  • 131.
    Bornholm, Martin
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Samuelsson, Gustaf
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Pavic, Robert
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Partiformning och beläggning av artiklar i produktionssystem2012Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Sammanfattning

    På grund av ökad konkurrens måste företag öka sin konkurrenskraft. Ett sätt för företag att öka sin konkurrenskraft är att utnyttja de resurser de besitter på ett mer effektivt sätt. Hur ett producerande företag styr sin produktion påverkar hur effektivt de utnyttjar sitt produktionssystem, lager och personal. Ett företag kan styra sin produktion genom att välja hur de partiformar och belägger de artiklar som utnyttjar ett produktionssystem.  Syftet med det här arbetet är att öka förståelsen för hur en modell för partiformning och beläggning av artiklar med varierande efterfrågan i ett produktionssystem där kapacitetsbrist råder kan se ut.

    Arbetet är en fallstudie där partiformning och beläggning av artiklar i ett produktionssystem analyseras. Kvalitativ forskning har bedrivits för att nå en djup förståelse för problemet. I arbetet beskrivs teorier om flöden, planering, partiformning och beläggning. Empirisk data som nämns i arbetet är beskrivningar av fallstudiens produktionssystem, de artiklar som produceras i systemet och planeringsprocessen företaget i fallstudien använder vid partiformning och beläggning. I analysen undersöks hur väl olika teorier passar för planering, partiformning och beläggning av fallstudiens produktionssystem.

    Genom en allmän diskussion om hur de beskrivna teorierna påverkar ett produktionssystems förmåga att ta tillvara på begränsad kapacitet och hantera varierande efterfrågan av artiklar nås en ökad förståelse för hur en modell kan se ut. De slutsatser som dras i arbetet är att partiformning och beläggning som sker för att optimera flödet kan öka effektiviteten i resursutnyttjandet. Ett sätt att optimera flödet är att belägga den resurs som anses vara kritisk först, beläggningen av den kritiska resursen styr därefter beläggningen av övriga produktionssystemet. Fler slutsatser som dras i arbetet är att en modell för partiformning och beläggning av artiklar med varierande efterfrågan i ett produktionssystem där kapacitetsbrist råder bör vara dynamisk. För att skapa en dynamisk modell kan beläggning och partiformning ske parallellt, det vill säga att partistorleken för en artikel påverkar beläggningen av en resurs, vilket i sin tur bör påverka partistorleken för resterande artiklar. 

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    fulltext
  • 132.
    Brandin, Jan
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Hulteberg, Christian
    Biofuel-Solution AB, Limhamn .
    Multi-function catalysts for glycerol upgrading2010Conference paper (Other academic)
    Abstract [en]

    During the last three years Biofuel-Solution, a privately held Swedish entity, has developed an IP-portfolio around gas-phase glycerol conversion into medium-value chemicals. The targeted chemicals have large to very large markets, to allow for use by more than a fraction of the glycerol available today without impacting the cost of the product. The reason behind is that glycerol is a by-product from the biofuel industry, including biodiesel and bioethanol. This indicates large production volumes, even though the glycerol is a fraction of the fuel produced. A by-product from any fuel process will be vast and therefore any chemical produced from this side-product will have to have a large market to offset it to. In order to avoid changing the fundamental market behavior, similar to what the biodiesel industry has done to the glycerol market.

    In the course of this work, several end-products have been targeted. These include plastic monomers, mono-alcohols and energy gases; using acrolein as a common starting point. To produce chemicals with high purity and efficiency, selective and active catalysts are required. For instance, a process for producing propionaldehyde and n-propanol has been developed to the point of demonstration and commercialization building on the gas-phase platform.

    By developing multi-function catalysts which perform more than one task simultaneously, synergies can be reached that cannot be achieved with traditional catalysts. For instance, by combining catalyst functionalities, reactions that are both endothermic and exothermic can be performed simultaneously.

    This mean lower inlet reactor temperatures (in this particular case) and a more even temperature distribution. By performing the dehydration of glycerol to acrolein in combination with another, exothermal reaction by-products can be suppressed and yields increased.

    It also means that new reaction pathways can be achieved, allowing for new ways to produce chemicals and fuels from glycerol. As in the case of ethane production from acrolein, where a catalyst surface has been devised where acrolein is first adsorbed. The actual mechanism is unknown but in speculation, the adsorbed acrolein is decarbonyled into ethylene and carbon monoxide on a first reaction site. The formed carbon monoxide diffuses to another active site, where it reacts with water through the so called water-gas shift reaction to carbon dioxide and hydrogen. Said carbon dioxide leaves as an end-product, and the hydrogen diffuses to another active site where it reacts with ethylene to form ethane. This gives a way of producing energy gases from glycerol in a very compact reactor set-up, effectively reducing footprint and capital cost and increasing productivity of an installation.

  • 133.
    Brandin, Jan
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Hulteberg, Christian
    Biofuel-Solution AB, Malmö.
    Levaue, Andreas
    Biofuel-Solution AB, Malmö.
    Green LPG2010Report (Other academic)
    Abstract [en]

    The use of energy gases with renewable origins will become important with diminishing fossil resources. This as the infrastructure of the gaseous fuels is well built out and the distribution networks already exist. LPG is one of the most versatile fuels around, perfect for rural areas and in many other applications. The fossil origin of the fuel will, in today’s climate and environmental debate, however position it as a thing of the past and not part of the future energy supply. The technology and development performed under this and previous programs with the Swedish Gas Centre will however suggest a way to bridge this conception and make LPG a part of the future energy mix. A good starting point for two and three carbon energy gases is glycerine, with its three carbon backbone. The reason for focusing on glycerine is its benign chemical nature, it is:• Harmless from a toxic standpoint• Chemically inert• Non-corrosive• Relatively high energy density• Zero carbon dioxide emissions It is also readily available as the production of biofuels (from which glycerine is a sideproduct) in the world has increased markedly over the last 10 year period. This glut in the glycerol production has also lowered worldwide prices of glycerine.Since the key step in producing energy gases from glycerol is the dehydration of glycerol to acrolein, this step has attracted much attention during the development work. The step has been improved during the performed work and the need for any regeneration of the catalyst has been significantly reduced, if not omitted completely. This improvement allows for a simple fixed bed reactor design and will save cost in reactor construction as well as in operating costs of the plant. The same conclusion can be drawn from the combination of the two functionalities (dehydration and hydrogenation) in designing a catalyst that promote the direct reaction of 1-propanol to propane in one step instead of two. The experiments with the decarbonylation of acrolein to form ethane show that the catalyst deactivation rates are quite rapid. The addition of noble metal to the catalyst seems to improve the longevity of the catalyst, but the coking is still too severe to provide for a commercially viable process. It is believed that there is a possible way forward for the decarbonylation of acrolein to ethane; it will however require additional time and resources spent in this area. In this work it has been shown that all of the catalytic steps involved in the production of propane from glycerol have sufficient longterm stability and endurance and it is motivated to recommend that the project continues to pilot plant testing stage.

  • 134.
    Brandin, Jan
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Hulteberg, Christian
    Lund University.
    Odenbrand, Ingemar
    Lund University.
    High-temperature and high concentration SCR of NO with NH3: application in a CCS process for removal of carbon dioxide2012In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 191, p. 218-227Article in journal (Refereed)
    Abstract [en]

    This study investigates several commercial selective catalytic reduction (SCR) catalysts (A–E) for application in a high-temperature (approximately 525 °C) and high-concentration (5000 ppm NO) system in combination with CO2 capture. The suggested process for removing high concentrations of NOx seems plausible and autothermal operation is possible for very high NO concentrations. A key property of the catalyst in this system is its thermal stability. This was tested and modelled with the general power law model using second-order decay of the BET surface area with time. Most of the materials did not have very high thermal stability. The zeolite-based materials could likely be used, but they too need improved stability. The SCR activity and the possible formation of the by-product N2O were determined by measurement in a fixed-bed reactor at 300–525 °C. All materials displayed sufficiently high activity for a designed 96% conversion in the twin-bed SCR reactor system proposed. The amount of catalyst needed varied considerably and was much higher for the zeolithic materials. The formation of N2O increased with temperature for almost all materials except the zeolithic ones. The selectivity to N2 production at 525 °C was 98.6% for the best material and 95.7% for the worst with 1000 ppm NOx in the inlet; at 5000 ppm NOx, the values were much better, i.e., 98.3 and 99.9%, respectively.

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    HighTempSCR
  • 135.
    Brandin, Jan
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Liliedahl, Truls
    Royal Institute of Technology.
    Unit operations for production of clean hydrogen-rich synthesis gas from gasified biomass2011In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 35, no Supplement 1, p. S8-S15Article in journal (Refereed)
    Abstract [en]

    The rebuild of the Växjö Värnamo Biomass Gasification Center (VVBGC) integrated gasification combined cycle (IGCC) plant into a plant for production of a clean hydrogen rich synthesis gas requires an extensive adaptation of conventional techniques to the special chemical and physical needs found in a gasified biomass environment. The CHRISGAS project has, in a multitude of areas, been responsible for the research and development activities associated with the rebuild. In this paper the present status and some of the issues concerning the upgrading of the product gas from gasified biomass into synthesis gas are addressed. The purpose is to serve as an introduction to the scientific papers written by the partners in the consortium concerning the unit operations of the process.

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    Unit operations
  • 136.
    Brandin, Jan
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Tunér, Martin
    Lunds Tekniska Högskola.
    Odenbrand, Ingemar
    Lunds Tekniska Högskola.
    Small Scale Gasifiction: Gas Engine CHP for Biofuels2011Report (Other academic)
    Abstract [en]

    In a joint project, Linnaeus University in Växjö (LNU) and the Faculty of Engineering at Lund University (LTH) were commissioned by the Swedish Energy Agency to make an inventory of the techniques and systems for small scale gasifier-gas engine combined heat and power (CHP) production and to evaluate the technology. Small scale is defined here as plants up to 10 MWth, and the fuel used in the gasifier is some kind of biofuel, usually woody biofuel in the form of chips, pellets, or sawdust. The study is presented in this report.

    The report has been compiled by searching the literature, participating in seminars, visiting plants, interviewing contact people, and following up contacts by e-mail and phone.

    The first, descriptive part of the report, examines the state-of-the-art technology for gasification, gas cleaning, and gas engines. The second part presents case studies of the selected plants:

    • Meva Innovation’s VIPP-VORTEX CHP plant
    • DTU’s VIKING CHP plant
    • Güssing bio-power station
    • Harboøre CHP plant
    • Skive CHP plant

    The case studies examine the features of the plants and the included unit operations, the kinds of fuels used and the net electricity and overall efficiencies obtained. The investment and operating costs are presented when available as are figures on plant availability. In addition we survey the international situation, mainly covering developing countries.

    Generally, the technology is sufficiently mature for commercialization, though some unit operations, for example catalytic tar reforming, still needs further development. Further development and optimization will probably streamline the performance of the various plants so that their biofuel-to-electricity efficiency reaches 30-40 % and overall performance efficiency in the range of 90 %.

    The Harboøre, Skive, and Güssing plant types are considered appropriate for municipal CHP systems, while the Viking and VIPP-VORTEX plants are smaller and considered appropriate for replacing hot water plants in district heating network. The Danish Technical University (DTU) Biomass Gasification Group and Meva International have identified a potentially large market in the developing countries of Asia.

    Areas for suggested further research and development include:

    • Gas      cleaning/upgrading
    • Utilization      of produced heat
    • System      integration/optimization
    • Small scale      oxygen production
    • Gas engine      developments
    Download full text (pdf)
    Gas Engine CHP for Biofuels.pdf
  • 137.
    Brandt, Anders
    et al.
    University of Southern Denmark, Denmark.
    Linderholt, Andreas
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    A Periodogram-Based Method for Removing Harmonics in Operational Modal Analysis2012In: International Conference on Noise and Vibration Engineering 2012 (ISMA 2012): Proceedings of a meeting held 17-19 September 2012, Leuven, Belgium. Including USD 2012 / [ed] P. Sas, S. Jonckheere & D. Moens, Leuven: Katholieke Universiteit Leuven, Department of Mechanical Engineering , 2012, p. 2625-2634Conference paper (Refereed)
    Abstract [en]

    In many cases where operational modal analysis is of interest, harmonic components are disturbing the estimation of modal parameters. Sometimes the harmonics can be included in the parameter estimation process and subsequently removed (because the damping values become unrealistically low). However, this is difficult if a natural frequency is very close to, or coincides with, a harmonic. In this paper we investigate a recently proposed method for removing harmonics when estimating spectral densities for operational modal analysis. The method is essentially based on removing the harmonics in a periodogram, prior to estimating the spectral density by smoothing the same periodogram. This makes it a very time efficient method, as the harmonic removal is integrated into the spectral analysis process. To produce data for testing the method, a finite element dynamic model representing a wind turbine was created. The MATLAB-based finite element code CALFEM was used to achieve a flexible description of the tower. An aerodynamic force representation excited the rotating structure. An unbalance in one of the blades was introduced to produce a harmonic at the rotation speed of the turbine. To validate the efficiency of the harmonic removal, modal parameters were estimated using simulated data prior to, and after, removing the harmonics. The results show that the harmonic removal with the proposed method is efficient.

  • 138.
    Brolin, Marina
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Westhoff, Monica
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    En blick av världen: Erfarenheter av att delta i internationaliseringsprojekt i gymnasieskolan2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Download full text (pdf)
    fulltext
  • 139.
    Burman, Jonatan
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonsson, Fredrik
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Framtagning av PPAP dokumentation för fordonsindustrin2011Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete är en del i högskoleingenjörsutbildningen vid linneuniversitetet i Växjö. Arbetet är utfört på Ackurat Industriplast AB i Lammhult. Syftet med arbetet är att ta fram samt utveckla fyra av kravelementen i Production Part Approval Process (PPAP) dokumentationen. Kravelementen vilka ingår inom ramen för detta arbete är flödesschema, process FMEA, styrplan samt kontrollinstruktioner.

    Ackurat har kunder inom fordonsindustrin, dessa kunder ställer höga krav på kvalitén hos produkterna från sina leverantörer. Denna kvalitetssäkring sker dels genom att leverantören skall följa krav ur ISO/ TS 16949 standarden där PPAP är en del av kvalitetssäkringen. Detta innebär att för varje nytt uppdrag så skall PPAP dokumentation bifogas tillsammans med ett utfallsprov. Ackurat upplever att den dokumentation som finns i dagsläget är bristfällig och i behov av uppdatering.

    Resultatet är utarbetat genom kartläggningsmetoden ” walk through” där en fallstudie av processer har använts . Informationen om processerna har insamlats genom observationer och intervjuer med personal i processerna.  Denna empiristiska information om Ackurats processer har sedan analyserats samt sammanställts med litteraturstudien i teoridelen.

    Examensarbetet resulterade i fem olika flödesscheman för att illustrera det verkliga flödet i Ackurats processer. Process FMEA utarbetades och åskådliggör felmöjligheter i processflödet. Genom kartläggningsarbetet sammanställdes en styrplan där alla kontroller i processerna ingår. Slutligen utarbetades kontrollinstruktioner för de kontroller som sammanställts i styrplanen.   

    Arbetet med kartläggningsarbetet av flödesschemat var en viktig del av genomförandet. Detta berodde på att följande dokument är uppbyggda från det aktuella flödesschemat. Stort fokus har således lagts i utvecklandet samt valideringen av de olika flödesschemana.

    Vid analys av dessa dokument kom författarna fram till att utformade dokument uppfyller syftet samt målen för arbetet. Denna slutsats framgick genom validering med berörd personal på Ackurat samt handledare.

    Likaväl som att framtagna dokument kan användas i PPAP dokumentation till Ackurats kunder så kan dokumenten användas till det interna förbättringsarbetet i företagets processer.

    Download full text (pdf)
    Framtagning av PPAP dokumentation för fordonsindustrin
  • 140. Bäck, Andreas
    et al.
    Grubbström, Jörgen
    Ecke, Holger
    Pettersson, Jens
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Operation of an Electroctrostatic Precipitator at a 30 MWth oxyfuel plant2011Conference paper (Other academic)
    Abstract [en]

    The performance of a full-scale ESP was studied at the Vattenfall AB oxyfuel pilot plant in SchwarzePumpe. The lignite-fired boiler has a 30 MWth top-mounted pulverized coal burner and was operated under conventional air combustion as well as oxyfuel combustion. The ESP was operated with varying numbers of fields in service and at different current/voltage settings. Particle number size distributionsdownstream the ESP were established on-line in the size range 0.015-10 μm, using an electrical mobility spectrometer and an aerodynamic particle sizer. The particle size distribution at oxyfuel operation was qualitatively very similar to the results obtained for air-firing. Gravimetric measurementsof total fly ash concentration showed outlet emissions below 5 mg/Nm3 when the ESP was operatedwith two fields in service at oxyfuel conditions.

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  • 141.
    Bäck, Andreas
    et al.
    Alstom Power Sweden AB.
    Grubbström, Jörgen
    Alstom Power Sweden AB.
    Ecke, Holger
    Vattenfall Research and Development.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Pettersson, Jens
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Operation of an Electrostatic Precipitator at a 30 MWth Oxyfuel Plant2011In: International Journal of Plasma Environmental Science and Technology, ISSN 1881-8692, Vol. 5, no 2, p. 141-145Article in journal (Refereed)
    Abstract [en]

    The performance of a full-scale ESP was studied at the Vattenfall AB oxyfuel pilot plant in Schwarze Pumpe. The lignite-fired boiler has a 30 MWth top-mounted pulverized coal burner and was operated under conventional air combustion as well as oxyfuel combustion. The ESP was operated with varying numbers of fields in service and at different current/voltage settings. Particle number size distributions downstream the ESP were established on-line in the size range 0.015-10 m, using an electrical mobility spectrometer and an aerodynamic particle sizer. The particle size distribution at oxyfuel operation was qualitatively very similar to the results obtained for air-firing. Gravimetric measurements of total fly ash concentration showed outlet emissions below 5 mg/Nm3 when the ESP was operated with two fields in service at oxyfuel conditions.

  • 142.
    Börjesson, Sara
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Kemiämnet i gymnasiet 1969-2007.: En läromedelsanalys med fokus på miljö- och säkerhetsfrågor2010Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Syftet med studien är att visa hur kemiämnet presenteras i gymnasieskolans läroböcker i kemi med regelbundna nedslag över en 40-årig tidsperiod och hur de knyter an till rådande läroplaner, utbildningspolitik samt miljö- och säkerhetsfrågor i undervisningen. Studien bygger på en innehållsanalys av gymnasieläroböcker i kemi, och som fördjupas med erfarna lärares berättelser om undervisningspraktikens förändring över tid.  Jag kopplar ihop fyra utbildningsfilosofier och undervisningstradition med läromedelsanalysen. Analysen visar att läromedlen från 1969, 1979 och 1989 är relativt lika med avseende på vilken bild som ges av kemiämnet. Från dessa årtionden ges bilden av att kemiämnet hör hemma i kemisalen. Läromedlen från 1999 och 2007 är mer lika varandra angående hur kemiämnet presenteras, det vill säga kemin är nu till för eleven och dennes vardagsliv. I min diskussion tar jag upp hur det kommer sig att intresse för kemi är svagt, trots att kemiämnet numera är mer lättillgängligt och knutet till det vardagsnära.

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  • 143.
    Candemir, Erkan
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Dimensioning and designing a testing rig for impact loading on beams: .2010Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    This report is product of a degree project accomplishment at Linnaeus University in Växjö, Sweden. It is about designing a testing rig for impact loading of beams for laboratory use.

    The specimens to be used were 1 meter long 8 standard profiles given in the project assignment. The first step in this project was to design and dimension a testing rig which is suitable for laboratory use. The height and the maximum mass were chosen according to laboratory use conditions and safety issues. The second step was designing the fixation for the test sample to the testing rig without any dislocation by the impact load. The third step was to measure the falling height of the mass onto the test sample and measure the deflection of the beam. In this case, the precision of falling height was not very important but measuring the deflection of the beam with the highest possible precision was most important. A measurement system is used considering this factor.

    The project started with the idea of affecting the impact loads on the standard steel construction beams. The aim of this project is to design an impact loading testing rig which can be used for the purpose of laboratory experiments and compare the real results from the experiments with the theoretical results from the calculations.

    In the project, Solid Works and AutoCAD software are often used both in the drawings and strength and stress analyses.

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  • 144.
    Caprolu, Giuseppe
    et al.
    Luleå Tekniska Universitet.
    Girhammar, Ulf Arne
    Luleå Tekniska Universitet.
    Källsner, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Johansson, Helena
    Tests on the splitting failure capacity of the bottom rail due to uplift in partially anchored shear walls2012In: WCTE World Conference on Timber Engineering, New Zealand, 15-19 July, 2012: Final Papers ; Architecture and Engineering Case Studies / [ed] Pierre Quenneville, 2012, p. 189-194Conference paper (Refereed)
    Abstract [en]

    Källsner and Girhammar have developed a new plastic design method for wood-frame shear walls at ultimate limit state. The method is capable of calculating the load-carrying capacity of partially anchored shear walls, where the leading stud is not necessarily anchored against uplift. In fully anchored shear walls, the leading stud needs to be anchored using some kind of hold-downs to resist uplift and the bottom rail needs to be fixed by anchor bolts to resist horizontal shear forces. In partially anchored shear walls, where hold-downs are not provided, the uplifting force is resisted by the sheathing-to-framing joints along the bottom rail. Hence, it is important that the bottom rail is anchored to the floor structure or foundation by anchor bolts and, therefore, able to transmit the forces to the structure below. Because of the eccentric load transfer, transverse bending is developed in the bottom rail and splitting of the bottom rail can occur. In order to use the plastic design method, a ductile behaviour of the sheathing-to-framing joints must be ensured. In this paper, results of tests on the splitting capacity of the bottom rail due to uplift in partially anchored shear walls are presented. Specimens with single-sided sheathing were tested, varying the size of washer, pith orientation of the bottom rails and anchor bolt position along the width of the bottom rail. The aim of the tests was to evaluate the influence of these parameters in order to avoid splitting failure of the bottom rail. Two types of brittle failure modes occurred during testing: (1) a crack opening from the bottom surface of the bottom rail and (2) a crack opening from the edge surface of the bottom rail along the line of sheathing-to-framing joints. These failure modes were mainly dependent on the washer size and the location of the anchor bolt. The results show that the distance between the edge of the washer and the loaded edge of the bottom rail has a decisive influence on the maximum load and the failure modes of the bottom rail.

  • 145.
    Caprolu, Giuseppe
    et al.
    Luleå Tekniska Universitet.
    Källsner, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Girhammar, Ulf Arne
    Luleå Tekniska Universitet.
    Vessby, Johan
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Analytical and experimental evaluation of the capacity of the bottom rail in partially anchored timber shear walls2012In: WCTE World Conference on Timber Engineering, Auckland, New Zealand, 15-19 July, 2012, 2012, p. 157-166Conference paper (Refereed)
    Abstract [en]

    Källsner and Girhammar have developed plastic design methods for light-frame timber shear walls that can be used fordetermining the load-carrying capacity when the shear walls are partially anchored. For such walls, the leading stud isnot fully anchored against uplift and tying down forces are developed in the sheathing-to-framing joints. Since theforces in the anchor bolts and the sheathing-to-framing joints do not act in the same vertical plane, the bottom rail willbe subjected to cross-wise bending, leading to possible splitting along the bottom side of the rail. Another possiblebrittle failure mode is splitting along the edge of the bottom rail in line with the sheathing-to-framing fasteners. Anexperimental program has been conducted using different anchor bolt locations, washer sizes and pith orientations. Afracture mechanics approach for the two failure modes is used to evaluate the experimental results. The comparisonshows a good agreement between the experimental and analytical results. The failure mode is largely dependent on thedistance between the edge of the washer and the edge of the bottom rail. The size of the washer seems also to havesome influence on the failure load. The fracture mechanics models seem to capture the essential behaviour of thesplitting modes and to include the decisive parameters. These parameters can easily be adjusted to experimental resultsand be used in design equations for bottom rails in partially anchored shear walls.

  • 146.
    Carlsson, Anna
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Utformningsförslag till villatomten Bergtorsken 102010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
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  • 147.
    Chen, Yousheng
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Nasrabadi, Vahid
    Chalmers.
    Linderholt, Andreas
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Abrahamsson, Thomas
    Chalmers.
    Model calibration of locally nonlinear structures using information from sub and super harmonic responses2012In: International Conference on Noise and Vibration Engineering 2012 (ISMA 2012): Proceedings of a meeting held 17-19 September 2012, Leuven, Belgium. Including USD 2012 / [ed] P. Sas, S. Jonckheere & D. Moens, Leuven: Katholieke Universiteit Leuven, Department of Mechanical Engineering , 2012, p. 2451-2464Conference paper (Other academic)
    Abstract [en]

    Large linear finite element models are commonly used in industry to represent global structural behavior and such models are often validated by use of data from vibrational tests. The validated models serve to predict the structural responses due to dynamic loads. Hence, it is important to have models that are able to represent the structural dynamics within the given operating envelope. When test data show proof of non linear behavior, a linear model may not be able to represent the dynamics well enough and thus a modification of the model is required. The main part of the structure may have a linear characteristic whereas localized physical processes can be sources of the observed nonlinearities. Model calibration of such locally nonlinear structures is studied in this paper. Specifically, the calibration process including the selection of appropriate data to be used for calibration of the model parameters chosen is treated. Here, synthetic test data stemming from a model of the Ecole Centrale de Lyon (ECL) nonlinear benchmark are used.

  • 148.
    Ciganovic, Renato
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Supportability Engineering in Wind Power Systems - Who Cares?: Considering important stakeholders and their requirements2011Licentiate thesis, monograph (Other academic)
    Abstract [en]

    Wind power is one of the fastest growing energy sources, which have advantages in terms of delivering clean, cheap and fast energy. Many actors and organizations have realized this potential, which has lead to exponential growth of the wind power over recent couple of years. Despite promising future of clean and green energy through wind there are still areas to be improved to tackle main hinders for further development on a larger scale. The larger scale development of wind power has up-to-date been reached in only few countries such asDenmarkandGermany. The most potential can be found through offshore wind turbines due to, among other, lesser height and noise restrictions than inland wind turbines as well as better wind resources.

    This thesis is mainly characterized by the mixed-method method, which is in its turn characterized by mixing different research methods such as induction, deduction and abduction as they might be suitable to apply during the different stages of the research process. In this thesis the system approach will be considered to model the scope of this study’s context. As this thesis was constructed as a theoretical study the systematic literature review was used as the main source for data collection. The synthesis of the reviewed articles was initially performed in a broad manner to show overall picture of research related to the scope of this thesis. In the following step, the adopted LCM tool was used to extract study specific data from the reviewed and additional articles. This enabled to link some of the current problems, in wind power area, and ‘unfulfilled’ stakeholder requirements.   

    This thesis aim was to identify important stakeholders and to address their respective requirements within the scope of supportability engineering applied in the wind power context, particularly stakeholder requirements that have not been considered by previous research. The purpose of it was to compare different requirements with current issues in the wind power sector. Conducted systematic literature review showed significant and costly (development) issues related to the supportability engineering such as reliability, availability, maintainability, accessibility problems etc. This was fully in line with the stakeholders’ requirements, which in several cases demanded higher dependability i.e. availability performance and its influencing factors. 

    The thesis also included definition of supportability engineering framework, through comparing several widely accepted and standardized theoretical concepts. This comparison enabled definition of more focused approach with requirements on the ‘supported system’ and to lesser extent the ‘support system’. These requirements are usually mixed within the different theoretical concepts. 

    The main findings from this study are that application of supportability engineering framework would lead to earlier identification of important stakeholders and their requirements. Considering these requirements, for instance availability and maintainability of the wind turbines, at earlier stages of the life cycle through better design and improved supportability infrastructure could potentially decrease amount of current problems in the wind energy sector in particular for the offshore part. Another result was that different stakeholders and their requirements were identified. Thesis contribution overall was a new ‘refined approach’ to deal with supportability issues through supportability engineering framework, whose main focus is the ‘supported system’.

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  • 149.
    Custovic, Emir
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Investigation of options for storm water management in southern Teleborg2011Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Changes in climate have resulted in increased rainfall flows into storm sewers in many parts of Scandinavia. This has resulted in the Southern Teleborg of Växjö has had capacity problems due to higher water levels.Studies of Sweco infrastructure AB has confirmed that there are capacity problems in the field and a solution in the form of an open equalization is supposed to storing storm water and reduce pressure on the stormwater pipes.

    This report has determined with data from SWECO and the task of Växjö municipality has sought to find a solution that can handle a ten-year rainfall with a duration of 10 minutes. A comprehensive delay has proved to be the best option for the area and it has resulted in a staircase design able to receive 632 cubic meters of water during heavy rainfalls.

  • 150.
    Daerga, Per-Anders
    et al.
    Umeå Universitet.
    Girhammar, Ulf Arne
    Luleå Tekniska Universitet.
    Källsner, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Slotted-in steel-plate connections for panel wall elements: experimental and analytic study2012In: WCT World Conference on Timber Engineering, New Zealand, 15-19 July, 2012: Final Papers, Architecture and Engineering Case Studies / [ed] Pierre Quenneville, 2012, p. 451-460Conference paper (Refereed)
    Abstract [en]

    This paper presents an experimental and analytical study of a steel plate connection for joining walls in the Masonite Flexible Building (MFB) system. These connections are used partly for splicing the wall elements and partly for tying down uplifting forces and resisting horizontal shear forces in stabilizing shear walls. The steel plates are inserted in a perimeter slot in the plyboard panel (a composite laminated wood panel) and fixed mechanically with screw fasteners. The load-bearing capacity of the slotted-in steel plate connections are determined experimentally and derived analytically for different failure modes. The test results show ductile post-peak load-slip characteristics, indicating that a plastic design method for shear walls can be applied to calculate the horizontal load-bearing capacity. The slotted-in steel plate connection concept can also be used for joining shear walls to transverse walls for tying down purposes in order to simplify the stabilization system of the building. The use of transverse walls for resisting uplifting forces introduces a three-dimensional behaviour of the wall junction and a more effective load transfer.

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