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  • 1.
    Blom, Åsa
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Schauerte, Tobias
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Thörnqvist, Thomas
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Utomhuskonstruktioner i trä: några erfarenheter från byggnation i trä av flerbostadshus2017Other (Other academic)
    Abstract [sv]

    Användandet av materialet trä i produkter är ett lån från naturen som förr eller senare genom nedbrytning av vedsubstansen ska återföras till det naturliga kretsloppet. Avseende användningen av solitt trä i produkter bestäms tidsperioden innan återföringen till naturen av produktens konstruktion och trämaterialet i sig självt i relation till den omgivande miljön samt användningen och hanteringen av produkten. En produkts förmåga att motstå, eller behålla sina egenskaper trots dessa yttre påfrestningar benämns dess beständighet.

  • 2.
    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.

  • 3.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Landscheidt, Steffen
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Nilson, Henrietta
    Linnaeus University, School of Business and Economics, Department of Organisation and Entrepreneurship.
    Resource utilization in a production cell for laminated veneer products2017In: Pro Ligno, ISSN 1841-4737, E-ISSN 2069-7430, Vol. 13, no 4, p. 142-147Article in journal (Refereed)
    Abstract [en]

    The concept of productivity is often used to determine how well resources are used in an operation, and it is usually determined as the ratio of what is consumed in the production. Laminated veneer products are considered complicated products often taking complex shapes, using a raw material with high variation, and requiring machining processes that create scrap material that needs to be handled. Therefore, maintaining high productivity in industries producing such products may become challenging. This study reports on productivity measurements in a production cell consisting of an adhesive, pressing and a processing station. The study seeks to increase the understanding of production-related problems in this industry. This research has been based on productivity measurement as well as on interactive discussions between researchers and workers. Measurement of cycle times indicated bottlenecks in the processing cell. The discussion led via cycle times, processing residues and chatter marks to an examination of the foundation and rigidity of the CNC-machine in the processing cell. The study indicated that the performance of the CNC machine did not correspond to expectations. The machine was too weak to handle the required output in an efficient manner. Thus, there is a need to determine the performance expected before a machine or machine group is purchased. An update of the existing purchasing literature and its dissemination will support the crystallization of the purchasing process as a way forward to support the industry.

  • 4.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sandberg, Dick
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Basic knowledge of wood properties for improved performance of laminated Veneer products2013In: Pro Ligno, ISSN 1841-4737, E-ISSN 2069-7430, Vol. 9, no 4, p. 549-556Article in journal (Refereed)
    Abstract [en]

    To ensure success in the production of laminated veneer products, it is necessary to acquire a sound basic understanding of the behaviour of the wood, and to understand the inherent reactions of wood to adhesive, heat, moisture, strain and stress. This can ensure an efficient wood utilization and promote the development of new processes and products that take advantage of the visco-elastic nature of wood.

     

    A shortcoming of the laminated bending process is that the products may become distorted after moulding and during use. In this study, we have examined how the performance of laminated veneer products can be improved through the implementation of basic knowledge of wood in the design and production process.

     

    The results show that the material and process parameters and storage in a changing relative humidity have a clear impact on distortion. Fibre orientation of the veneers in the moulded assembly was the most critical parameter to control. Fibre deviations mainly resulted in twist of the product. A moisture content in one veneer deviating from that of the rest of the veneers in the assembly before moulding resulted in distortion of the laminated veneer products both after moulding and during use. To decrease the negative effect of fibre orientation and moisture content on shape stability, the veneer should be straight-grained and well-conditioned to a moisture level adapted to the use of the final product. Special care should also be taken to orientate the veneers during assembly before moulding.

  • 5.
    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.

  • 6.
    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.

  • 7.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sandberg, Dick
    Luleå tekniska universitet.
    Modification of surface veneer to reduce damage in laminated veneer products during manufacturing2014In: Final Cost Action FP0904, Recent Advances in the Field of TH and THM Wood Treatment, May 19-21, Skellefteå, Sweden: Book of abstracts / [ed] Dick Sandberg and Mojgan Vaziri, Luleå: Luleå tekniska universitet, 2014, p. 50-51Conference paper (Refereed)
  • 8.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sandberg, Dick
    Luleå tekniska universitet, Luleå University of Technology.
    Moisture-induced distortion of laminated veneer products2014In: Forest Products Society (FPS)  68th International Convention, 2014Conference paper (Refereed)
  • 9.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sandberg, Dick
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Moisture-induced distortion of laminated veneer products2013In: Proceedings of the 9th meeting of the Northern European network for wood science and engineering (WSE): September 11-12, 2013, Hannover, Germany / [ed] Christian Brischke & Linda Meyer, Hannover, Germany, 2013, p. 178-183Conference paper (Refereed)
    Abstract [en]

    Laminated veneer products consist of veneers bonded together with adhesive into a predetermined shape. Since wood is a hygroscopic material and also anisotropic by nature, laminated veneer products are especially shape-sensitive to changes in moisture content. A deviation from the intended shape is a problem for both the manufacturers and users of the final products and annually such deviations cause great economic losses in the manufacturing industry.

     

    To illustrate the influence of moisture on distortion and shape stability, studies have been performed in industrial conditions and in a laboratory environment. Veneers of beech and birch and a seat shell moulded from these veneers were used in the study. Distortion, i.e. spring-back, position and twist, has been determined directly after moulding and during subsequent moisture and drying cycles.

     

    The distortion follows more or less slavishly the changes in relative humidity around the product. The distortion is generally small directly after moulding but, after the laminates have been exposed to a variation in relative humidity, the distortion increases. Some of the problems of poor shape stability that may arise later in the bending process can be reduced if attention is paid to moisture content and fibre orientation already in the production of the veneer.

     

    To achieve good shape stability of laminated veneer products in practice, the following should be followed by the manufacture industry:

    • develop      cooperation with suppliers of veneer and set requirements of veneer with regard      to deviation of the fibre orientation, and require that the veneer be dried      and conditioned to a moisture content consistent with production,
    • control      incoming veneers with respect to fibre orientation and moisture content,
    • plan warehousing      of veneers and ensure adequate conditioning, and
    • consider      the orientation of the veneers and the species.
  • 10.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sandberg, Dick
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Shape stability of laminated veneer products: an experimental study of the influence on distortion of some material and process parameters2013In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 8, no 3, p. 198-211Article in journal (Refereed)
    Abstract [en]

    Laminated bending of veneers is a common used and important process for manufacture of components primarily for furniture and interior purposes. According to the use, such products are in general very sensitive to variations in the intended shape, i.e. distortion can be of great problem and more or less destroy the use of the final product. The most critical mode of distortion is twist, but also other changes in shape may be of interest to keep low. The causes to distortion of laminated bended veneer products can be of material (veneer, adhesive and the combination of these), design, processes and climate nature and there is a challenge to know which parameters which are of major importance for distortion, both directly after moulding and when the products are in use.

    In this study, the influence of type of UF-adhesive hardener, i.e. liquid or powder, water content of adhesive, adhesive distribution, variation of moisture content of glued veneers, and fibre orientation of veneers, on twist and position for a 3D-veneer construction (a chair seat shell) has been studied. Distortion, i.e. twist and position, has been determined directly after moulding and after moisture cycling. The moisture cycling was to simulate and accelerate conditions that the shells are subjected in use. The aim of the work is to study how the above mentioned material and process parameters influence the shape stability of the products.

    The results show that the climate, i.e. how a certain level of temperature and relative humidity influence the moisture content of the moulded product, has a clear impact on the distortion of the product in use. An increase in moisture content results in a significant increase in distortion and vice versa. The level to which the moulded products distort during climate variation can be controlled through controlling material, design and process parameter during moulding. Of the studied parameter mentioned above, a deviation in fibre orientation of the veneers in the moulded assembly is the most critical parameter to have under control to minimize distortion. The fibre deviation mainly results in an increase in twist. A high moisture content of a veneer vis-à-vis the rest of the veneers in the assembly before moulding, will result in increased position and twist of the moulded product in use. The difference of moisture content between veneers and the position of veneers with high moisture content in the assembly will influence the level of distortion. Other studied parameter also influences the distortion to a lesser extent and can in these cases be related to the moisture distribution in the mouldings.

  • 11.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sandberg, Dick
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Shape stability of laminated veneer products: How to decrease the negative effects of fibre deviation?2013In: Forest Products Society (FPS)  67th International Convention, Madison: Forest Products Society , 2013Conference paper (Refereed)
    Abstract [en]

    A shortcoming of the laminated bending process is that the products may become distorted after moulding and during use. Annually, significant financial losses have incurred in the furniture and interior design industries as a result of distorted products. In this study, we have examined the influence of deviation of fibre orientation of individual veneers on distortion of a moulded shell to find ways to improve shape stability of laminated veneer products.

    Ninety cross-laminated shells, consisting of 7 veneers of Birch (Betula pubescens Ehrh.) with a total thickness of 3.6 mm, were studied. The in-plane dimensions of the veneer were 400x660 mm. All the veneers were straight-grained, but to simulate deviation in fibre orientation some of the individual veneers were oriented 7 degrees relative to the main orientation of the other veneers in the laminate. Distortion was determined directly after moulding and after storage in a changing relative humidity.

    The results show the well-known fact that deviation of fibre orientation of the veneers in the laminate influences the shape stability of the product. The results from this study, however, also show how the placement of the abnormal veneers in the laminated veneer products influences the degree of distortions. From this basic knowledge some improvements for production of laminated veneer products were suggested.

  • 12.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sandberg, Dick
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Shape stability of THM-processed laminated veneer products glued with bio-based adhesive systems2013In: Evaluation, processing and predicting of THM treated wood behaviour by experimental and numerical methods / [ed] Carmen-Mihaela Popescu and Maria-Cristina Popescu, Iasi, Romania, 2013, p. 99-100Conference paper (Refereed)
  • 13.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sandberg, Dick
    Luleå tekniska universitet, Luleå University of Technology.
    Veneer modification for improved formability when moulding laminated veneer products2014In: Forest Products Society (FPS)  68th International Convention, 2014Conference paper (Refereed)
  • 14.
    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)
  • 15.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Nilson, Henrietta
    Linnaeus University, School of Business and Economics, Department of Organisation and Entrepreneurship.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Landscheidt, Steffen
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Downtime causes in a production cell for laminated veneer products2017In: 23rd International Wood Machining Seminar Proceedings / [ed] Marcin Zbiec and Kazimierz Orlowski, Warsaw, Poland: The Polish Chamber of Commerce of Furniture Manufacturers , 2017, p. 28-35Conference paper (Refereed)
    Abstract [en]

    Productivity is often used to determine how well resources are used for an operation. Most often, the ratio of what is produced to what is required to produce it determines productivity. Laminated veneer products are considered complicated products often with complex shapes, a raw material with high variation, and machining processes that create scrap materials that need to be handled. Therefore, keeping a high productivity in the industries producing such products may become challenging. This study reports productivity measurements in a production cell consisting of an adhesive, pressing and processing station. The study seeks to increase understanding of production-related problems in this industry. The research has been using productivity measurement as well as interactive discussions between researchers and workers.

    Measurement of downtime causes were made for 20 days, for a total of approximately 300 hours. The production cell had 1,299 minutes of stops. Of those, 450 minutes were one-time events. The rest were intermittent disturbances. Many of them could be explained by the dust-laden air and processing residues but were also related to veneer and adhesive. There is a need for determining material and processing parameters; however, the first priority is cleaning the factory.

    From a social perspective, some other issues must be added to the discussion of this paper. First and foremost, the business has gone through a transformation from a family business to a privately held firm. From the non-family employee’s view, this is a huge change. This has resulted in unclear roles and responsibilities within the company, which has also affected the productivity of the company.

  • 16.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Pfriem, Alexander
    Eberswalde University for Sustainable Development, Germany.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Temporary buildings in reusable lightweight material design2016In: Proceedings of the 2016 World Conference on Timber Engineering (WCTE), Vienna: Vienna University of Technology , 2016Conference paper (Refereed)
    Abstract [en]

    There is a growing need and market for temporary buildings for various purposes, including largeconstruction projects in the tourism and events sectors or in civil protection. This paper gives an overview about the useof reusable lightweight materials in temporary buildings. Based on a project proposal submitted to the 7th framework, anew concept of temporary buildings is proposed. This concept combines the advantages of the premanufacturing of asmall number of parts and wooden components and a flexible and modular erection of the temporary building. Thefocus is on fast establishment with a maximum of three persons. A flexible and modular extension is possible.Assembling and disassembling the individual components with novel connect systems, adapted from the furnitureindustry, is proposed.This project aims to bring these concepts into new temporary buildings with new, reusable, and flexible lightweightdesign.

  • 17.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sandberg, Dick
    Luleå tekniska universitet, Luleå University of Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Influence of veneer orientation on shape stability of plane laminated veneer products2014In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 9, no 4, p. 224-232Article in journal (Refereed)
    Abstract [en]

    One of the most important quality aspects of a laminated veneer product is its shape stability under changing relative humidity (RH). This study aimed to establish an understanding of how the orientation of individual veneers in the laminate, i.e., orientation according to fibre orientation and orientation of the loose (the side with ‘lathe checks’) or tight side of the veneer, affects the shape stability. Three-ply laminates from peeled veneers of beech (Fagus sylvatica L.) were studied. The four types of laminate were the following: loose sides of all veneers in the same direction (cross and parallel centre ply) and loose sides of the outer veneers facing inward (cross and parallel centre ply). Four replicates of each type yielded 16 samples. The samples were exposed to RH cycling at 20% and 85% RH at 20°C, and the shapes of the samples were determined. The shape stability was influenced by the veneer orientation. Laminations with the middle veneer perpendicular to the top and bottom veneer (cross-laminated) showed the best shape stability, especially when the loose sides of the veneers were oriented the same direction. In parallel-laminated veneers, the laminates with opposite directions of the loose sides in the two outermost veneers showed the best shape stability. The major explanation of the behaviour of the laminates is that the loose side expanded more than the tight side from the dry to the humid climate, which was shown by optical 3D deformation analysis (ARAMISTM). After RH cycling, the laminates with cross plies showed visible surface checks only when the tight side was facing outwards.

  • 18.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sterley, Magdalena
    SP Technical Research Institute of Sweden.
    Sandberg, Dick
    Luleå University of Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    The effect of veneer modification on the bond-line strength in laminated veneer products2015In: Pro Ligno, ISSN 1841-4737, E-ISSN 2069-7430, Vol. 11, no 4, p. 43-49Article in journal (Refereed)
    Abstract [en]

    A major problem in the manufacture of three-dimensional laminated veneer products (LVP) isdamage due to stretching and/or buckling of the veneer. To reduce or eliminate this problem, veneerdensification or adding a strengthening layer to the veneer can be an alternative. To study how veneermodification influences the veneer-to-adhesive bond strength, three methods of modification werestudied in relation to an unmodified reference veneer: (1) densified veneer, (2) veneer pre-bonded withpaper and hot melt adhesive (HMA), (3) veneer pre-bonded with non-woven polypropylene (NW)fabric glued to the veneer (a) with a urea formaldehyde (UF) adhesive, (b) with a mixture of UF andpolyvinyl acetate (PVAc) adhesive, and (c) with a PVAc adhesive. Densification, pre-bonding withpaper, and NW with UF/PVAc adhesive mixture resulted in no or only a slight decrease in strength ofthe bond-line compared to the reference. NW glued with UF or PVAc adhesive showed a considerablereduction in the strength of the bond-line. The climatic cycling had no significant influence on the bondstrength.

  • 19.
    Blomqvist, Lars
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sterley, Magdalena
    SP Wood Technology.
    Sandberg, Dick
    Luleå tekniska universitet, Luleå University of Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    The influence of veneer modification on adhesive bond strength2014In: Proceedings of the 10th meeting of the Northern European network for wood science and engineering (WSE) / [ed] Peter Wilson, Edinburg, Scotland, 2014, p. 150-155Conference paper (Refereed)
  • 20. Bonnet, Marie
    et al.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Water transport in hardwoods above FSP: case of birch2014Conference paper (Other academic)
  • 21.
    Grubîi, Victor
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Occurence of shake in oak (Quercus spp.) and its effect on flooring top-layer quality2018In: 8th Hardwood Conference. Sopron, Hungary. 25-26 October 2018: With special focus on "New Aspects of Hardwood Utilization - from Science to Technology" / [ed] Robert Németh, Alfred Teischinger, Peter Rademacher, Miklos Bak, Sopron, Hungary: University of Sopron Press , 2018, p. 59-60Conference paper (Refereed)
    Abstract [en]

    Oak (Quercus spp.) is generally preferred wood species as surface material in flooring products realization. The presence of defects such as cracks limits the utilization of the raw material and ultimately, limits the competitiveness of wood in the flooring market when compared to other materials.

    The objective of this study was to develop the theoretical aspects for crack-type identification based on the appearance of the sawn top-layer lamellas and evaluate the influence of crack occurrence on the quality of flooring top-lamellas.

    The results of this study provide an insight for crack-type identification on the surface of oak (Quercus spp.) flooring top-lamellas and wood quality optimisation aspects.

  • 22.
    Grubîi, Victor
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Occurrence of shake in oak (Quercus ssp.) and it's effect on flooring top-layer quality2018In: 8TH HARDWOOD CONFERENCE WITH SPECIAL FOCUS ON NEW ASPECTS ON HARDWOOD UTILIZATION - FROM SCIENCE TO TECHNOLOGY / [ed] Nemeth, R Teischinger, A Rademacher, P Bak, M, University of Sopron, Hungary , 2018, p. 59-60Conference paper (Refereed)
    Abstract [en]

    Oak (Quercus ssp.) is generally preferred wood species as surface material in flooring products realization. The presence of defects such as cracks limits the utilization of the raw material and ultimately, limits the competitiveness of wood in the flooring market when compared to other materials. The objective of this study was to develop the theoretical aspects for crack-type identification based on the appearance of the sawn top-layer lamellas and evaluate the influence of crack occurrence on the quality of flooring top-lamellas. The results of this study provide an insight for crack-type identification on the surface of oak (Quercus ssp.) flooring top-lamellas and wood quality optimisation aspects.

  • 23.
    Gustafsson, Åsa
    et al.
    Linnaeus University, School of Business and Economics, Department of Management Accounting and Logistics.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Does quality matter?2016In: Implementation of wood science in woodworking sector: proceedings / [ed] Ivica Grbac, Zagreb: University of Zagreb, Faculty of Forestry , 2016, p. 263-270Conference paper (Refereed)
  • 24.
    Gustafsson, Åsa
    et al.
    Linnaeus University, School of Business and Economics, Department of Management Accounting and Logistics.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Quality assurance practices in the sawmill industry2014In: Abstracts SSFE 2014 / [ed] Anders Roos, 2014Conference paper (Refereed)
  • 25.
    Gustafsson, Åsa
    et al.
    Linnaeus University, School of Business and Economics, Department of Management Accounting and Logistics.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Salinas, Miguel
    Linnaeus University, Faculty of Arts and Humanities, Department of Design.
    Realization of a higher education interdisciplinary program2016In: Lärarlärdom 2016: Högskolan Kristianstad / [ed] Claes Dahlqvist, Stefan Larsson, Kristianstad University Press , 2016, p. 55-69Conference paper (Refereed)
    Abstract [en]

    For most companies and organizations there is a need to employ graduates with interdisciplinary skills. Hence it becomes important for universities and teaching institutions to graduate students with this knowledge. At the same time there is need for universities and teaching institutions to position itself in relation to its competitors. This is an apparent challenge for universities and teaching institutions, as developing and offering interdisciplinary programs requires them to break the normal traditional university structure involving different faculties applying different operating models. However, by succeeding with this, universities will create a competitive advantage over their competitors.

    At Linnaeus University, Sweden, an interdisciplinary program called Innovation through Business, Engineering and Design involving three faculties has been developed.  The program was initiated in 2011 and began in 2014 with 15 students. The program is dimensioned for about 30 students, ten from each faculty. This paper reports on the realization of the program and the resources needed to do this. Knowing the resource requirements is necessary in order to make correct decisions regarding program development and to avoid decisions on invalid grounds. Knowing the activities to be performed is an essential pre-requisite for resource planning. Consequently the purpose of this paper is to identify organization roles and activities as well as the resources required in order to realize an interdisciplinary program.

    The paper is empirical in nature and data has been collected using interactive research. Interactive research stresses the researchers (i.e. the authors) joint learning together with other members of the development group and the other actors involved. 

    The paper concludes that in order for a realization to take place organizational roles (such as project leader and product coordinators), and activities such as creating deliverable document and schedule are necessary. The differences between a single-disciplinary program and a multidisciplinary program lies rather in the complexity and time management of performing the activities needed then in the actual performing. There is primarily a need for human capital, as the suitable faculty members are needed, as well as there is a need financial capital.

  • 26.
    Jalilzadehazhari, Elaheh
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Material properties of wooden surfaces used in interiors and sensory stimulation2018In: Presented at Forum Wood Building Nordic 2018, 27-28 september, Växjö, 2018Conference paper (Other academic)
  • 27.
    Jalilzadehazhari, Elaheh
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Material properties of wooden surfaces used in interiors and sensory stimulation2019In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 14, no 4, p. 192-200Article in journal (Refereed)
    Abstract [en]

    By covering interiors, such as walls, ceilings and floors, with wooden surfaces, one can change the quality of indoor environments and thereby affect both psychological and physiological responses. Psychological responses refer to individuals’ emotional reactions toward interiors, while physiological responses include changes in the activity of the brain, the autonomic nervous system, the endocrine system, and the immune system. The above-mentioned responses considered in this study are those caused by visual, auditory, olfactory and tactile stimulation from interior wooden surfaces. Although earlier studies have presented valuable information on this subject, questions remain about the material properties of wood which are associated with the stimulation. Specifying the material properties can support architects, designers and engineers who intend to use wood in interiors for improving psychological and physiological responses. A literature study therefore has been conducted to determine (i) the material properties of wood which are associated with sensory stimulation, and (ii) to specify relevant recommendations or requirements which should be fulfilled when covering interiors with wooden surfaces. The results show a lack of knowledge regarding the material properties of wood and the degree in which it affects sensory stimulation.

  • 28.
    Jalilzadehazhari, Elaheh
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Applying a decision-making framework for resolving conflicts when selecting windows and blinds2019In: Architectural Engineering and Design Management, ISSN 1745-2007, E-ISSN 1752-7589, Vol. 15, no 5, p. 382-401Article in journal (Refereed)
    Abstract [en]

    The selection of the most appropriate window and blind design is a challenging task due to the existence of potential conflicts between visual comfort, thermal comfort, energy consumption and life cycle cost. Resolving these conflicts relies on a trade-off window and blind design. This research applied a decision-making framework to select a trade-off window and blind design for an office room in Sweden. The decision-making framework was developed based on integrating the non-dominated sorting genetic algorithm-II and the analytical hierarchy process. The first step in the application of the framework was to generate a model of the office room using EnergyPlus. Six types of window and four types of blind; an internal venetian blind, an internal roller curtain, an external venetian blind and an external overhang panel, were modelled in EnergyPlus. The second step was to run an optimisation using non-dominated sorting genetic algorithm-II. For this purpose, various window and blind design variables were specified in modeFRONTIER platform. The third and last step in the application of the decision-making framework was to select a trade-off window and blind design using analytical hierarchy process. The results show the strength of the decision-making framework in selecting a trade-off design, and thereby the ability to resolve conflicts through intelligent use of simulation in analyzing big-data in built environment, energy and cost sectors. Since, the computation and processing power for performing simulations is constantly increasing, architects and designers can exploit the decision-making framework and locate a trade-off design in a relatively short period of time.

  • 29.
    Jalilzadehazhari, Elaheh
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Comparing the profitability of various renovation packages in Swedish residential building sector: case study2019In: Sustainable built environment conference (SBE 2019). 6-7 August, Tokyo, Japan, 2019Conference paper (Refereed)
    Abstract [en]

    Swedish government adopted national targets to reduce total energy consumption and mitigate environmental impacts. At this point, detached houses play an important role, since they account for a large share of dwelling stock in this country. The majority of these buildings are affected by technical deteriorations in building envelopes and heating, ventilation and air condition systems. Accordingly, there is a need for a deep renovation strategy, which covers both energy efficiency measures and economic issues. Additionally, a deep renovation can improve indoor climate, which contributes to the enhanced health and wellbeing. Thus, the aim of this study is to compare the efficiency of eight different renovation packages in reducing energy consumption and providing economic benefits in a detached house in Sweden. The renovation packages include 1) improving the U-value of building envelopes; 2) adding a heat recovery for ventilation system; 3) installing a ground source heat pomp for supporting heat demand and domestic hot water; 4) combination of renovation package 1 and 2; 5) combination of renovation package 1 and 3; 6) combination of renovation package 2 and 3; 7) combination of renovation package 1, 2 and 3; and 8) combination of renovation package 1, 2, 3 along with installing photovoltaic cells for producing electricity. The reduction in energy consumption was calculated in kWh/m². year for each renovation package, while the economic benefit was obtained by calculating the payback period during a lifespan of 50 years and internal rate of return with interest rates of 1%, 3% and 6%. The results indicate that renovation package 8 has the highest potential in reducing total energy consumption, while renovation package 3 is the most profitable solution since it provides the shortest payback period with the highest internal rate of return. The results help to define and project efficient energy policies in Sweden.

  • 30.
    Jalilzadehazhari, Elaheh
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Peter
    Jönköping University, Sweden.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Determinants of users’ acceptance of a computer-based system2019In: 36th CIB W78 2019 Conference ICT in Design, Construction and Management in Architecture, Engineering, Construction and Operations (AECO), 18-20 September, 2019, Newcastle, United Kingdom: University of Northumbria , 2019Conference paper (Refereed)
    Abstract [en]

    Sweden has an ambitious target to attain 50% more efficient energy use by 2030. Improving the energy performance of buildings provides a great opportunity to achieve the above-mentioned target. At this point, windows play a substantial role in improving indoor environmental quality and reducing energy consumption and cost. A computer-based system was therefore developed, which allows selecting a suitable window design. The computer-based system was intended to be used in a large-sized window and door manufacturing company in Sweden. However, the benefits of implementing the computer-based system cannot be realized until users accept using it. Former literature employed the technology acceptance model to investigate the influence of external variables on cognitive beliefs and trace their effects on users’ intention and actual system use. A successful application of TAM relies on the specification of the external variable. Accordingly, this paper conducted a systematic literature review to determine the external variable, affecting users' acceptance, thereby extended TAM. The analyses of results showed that organizational, individual, technological and environmental characteristics were the most influential external variables when investigating determinants of users' acceptance toward a computer-based system. Organizational characteristics contained mainly top management support, training, organizational culture, and organizational size, while individual characteristics embraced users’ previous knowledge and experience. Technological characteristics comprised information quality and system quality, meanwhile environmental characteristics included fulfillment of regulations and competitiveness. The extended TAM overcomes limitations attributed to the unified theory of acceptance and use of technology model since it considers attitude as direct determinants of intentions. In addition, the extended TAM is advantageous when compared with technology, organization, environment framework, because it has clear constructs, which allows tracing the influence of external variables on cognitive beliefs, and thereby their effects on users’ intention and actual system use. The extended TAM will be used to investigate determinants of users’ acceptance of the computer-based system in the manufacturing company in Sweden and compare the effect of external variables on users' acceptance.

  • 31.
    Jalilzadehazhari, Elaheh
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Peter
    Jönköping University.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Application of analytical hierarchy process for selecting an interior window blind2017In: Architectural Engineering and Design Management, ISSN 1745-2007, E-ISSN 1752-7589, Vol. 13, no 4, p. 308-324Article in journal (Refereed)
    Abstract [en]

    Window blinds have a substantial role in shaping the energy consumption and improving thermal comfort and visual comfort. However, difficulties in selecting a window blind remain, due to existence of potential conflicts between visual, thermal, energy and life cycle cost. To overcome this problem, this study evaluates the performance of interior blinds, including venetian with slat of 0° and 45°, roller and double pleated blinds with respect to visual, thermal, energy and life cycle cost. Later, the Analytical hierarchy method (AHP) is used for selecting the best blind based on trade-off among the visual, thermal, energy and life cycle cost. In using AHP, visual comfort is determined as most important objective with a weight of 52%. The results show that venetian blind with slat of 0° drawn 100% is the trade-off blind. Accomplishing the sensitivity analysis on blinds’ global weight shows that venetian blind with slat of 0° drawn 100% remains the trade-off blind until the weight of energy and life cycle cost is below 37% and 57% respectively and the weight of visual comfort is above 4%. However, changing thermal comfort weight has no impact on ranking of the blinds. This study shows the capability of AHP in managing the conflicts.

  • 32.
    Jalilzadehazhari, Elaheh
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Peter
    Jönköping University, Sweden.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Developing a decision-making framework for resolving conflicts when selecting windows and blinds2019In: Architectural Engineering and Design Management, ISSN 1745-2007, E-ISSN 1752-7589, Vol. 15, no 5, p. 357-381Article in journal (Refereed)
    Abstract [en]

    Windows and blinds play a significant role in both shaping energy consumption and enhancing indoor comfort. But there are still difficulties with selecting windows and blinds due to the existence of potential conflicts between visual comfort, thermal comfort, energy consumption and life cycle cost. A literature review was conducted with the purpose of developing a decision-making framework that resolves the conflicts, and allows selecting a window and blind design based on trade-off between visual comfort, thermal comfort, energy consumption and life cycle cost. The decision-making framework was developed by integrating non-dominated sorting genetic algorithm-II as an optimisation algorithm with analytical hierarchy process as a multi-criteria decision-making method. The optimisation algorithm considers different window and blind design variables and analyses multiple designs, while the multi-criteria decision-making method ranks the optimization results and selects a trade-off design. An operating package enabled the decision-making framework to be automated. The operating package was obtained by coupling EnergyPlus as a simulation tool and modeFRONTIER as an integration platform. The decision-making framework was developed to select a trade-off window and blind design through intelligent use of simulation in analysing big-data in built environment, energy and cost sectors. Application of the framework ensures the minimum visual and thermal comfort thresholds with the lowest energy demand and cost. Architects and designers can use the framework during the design or renovation phase of residential and commercial buildings.

     

  • 33.
    Jalilzadehazhari, Elaheh
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Pardalis, Georgios
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Peter
    Jönköping University.
    Application of multi-objective optimization for resolving conflicts when selecting windows2019In: The 9th International Conference on Sustainable Development in the Building and Environment(SuDBE2019)& the International Forum of Green and Healthy Buildings., Reading and Cambridge, UK, 2019Conference paper (Refereed)
    Abstract [en]

    Sweden passed legislation to achieve a target of net zero greenhouse gas emissions by the end of 2045. The Energy Performance of Building Directive further obliged European countries to ensure zero-energy building codes and improve the quality of indoor environments when buildings are renovated, as approximately 40% of total greenhouse gas emissions in Sweden are produced while heating buildings. Windows currently play a significant role in improving the quality of indoor environments and cutting total energy consumption, thereby reducing greenhouse gas emissions and mitigating environmental impact. Selecting a suitable window design is a complicated task compounded by two main difficulties: i) the availability of multiple window designs, each with a different glazing system, size, form and position; and ii) conflict between visual comfort, thermal comfort and energy consumption. Previous studies have primarily analysed a limited selection of window designs; however, analysing a wide variety of glazing systems, sizes, forms and positions will help resolve the abovementioned difficulties, thereby ensuring zero-energy building codes while improving the quality of an indoor environment. A multi-objective optimization was therefore completed to analyse the performance of a wide variety of window design variables and select suitable designs for an office room in Sweden. The results show the potential of multi-objective optimisation to resolve the difficulties of selecting suitable window designs.

  • 34.
    Johansson, Jimmy
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Aspects on Automatic Grading of Wood for Improved Material Utilization in the Swedish Hardwood Sawmill Industry2011In: International Scientific Conference on Hardwood Processing, October 16-18, 2011 Virginia Tech, Blacksburg, VA, USA: Current Session II, 2011Conference paper (Refereed)
    Abstract [en]

    Historically, the selection of wood for manufacturing furniture and joinery has been made with great care. The basis has been the un-edged sawn and dried pieces of wood. Alternatively, selection has already been made in the forest. The trained eye and the skilful craftsmen have been crucial for the result. In today’s industrial processes, this methodology is hard to achieve with the non-homogeneous wooden material. This article explores developmental trends considering the work within the Swedish hardwood value chain. The aim of this manuscript is to discover how it is possible to utilize today’s available information technology, e.g. scanners in the industrial process, as a help to make more optimal use of the wooden raw material. Together with customers of a hardwood sawmill, a product was selected and followed backwards in the hardwood value chain. Crosscutting scanner data was collected based on wood origin with known log-quality. The length distribution of crosscut components was simulated based on different quality grading criteria. The results from the study may be used as a help in production planning, in the selling process, or as a tool in product development where raw material accessibility may be determined in relation to the product design.

  • 35.
    Johansson, Jimmy
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Förutsättningar för konkurrenskraftigt utnyttjande av svenskat lövtimmer i svenska lövsågverk2003Report (Other academic)
  • 36.
    Johansson, Jimmy
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Kvalitetsutveckling i svensk lövträindustri2011In: Ekbladet, ISSN 0283-4839, no 26, p. 24-28Article in journal (Other (popular science, discussion, etc.))
  • 37.
    Johansson, Jimmy
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Mechanical processing for improved products made from Swedish hardwood2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Swedish hardwood is today used in the energy, pulp and mechanical hardwood industries. Only very small volumes of Swedish hardwood are, however, consumed by the mechanical industry that normally pays the highest timber price. The smallness of the volumes used for mechanical refinement is a result both of forestry not focusing on the production of hardwood for these uses, and of the fact that the mechanical hardwood industry, particularly the sawing industry, is not designed to process the existing raw material in an optimal manner. This thesis discusses the possibilities of improving the conditions for the mechanical refinement of hardwood. The aim of the work has been to investigate the possibilities of developing products and methods for processing of Swedish hardwood.

    The thesis proposes a new manufacturing system for Swedish hardwood to better utilize the inherent properties of the wood material. The system is based on the so-called PrimWood Method and the star-sawing concept. Compared to normally sawn wood, the sawing concept utilizes the raw material more efficiently with regard to volume yield, and increases the distance between knots in the sawn wood. The material produced has vertical annual rings which give the wood smaller movements as a result of moisture variations and a different textural appearance. Using the PrimWood Method for hardwood would make it possible to more closely match customer requirements regarding hardwood products.

    Since Swedish hardwood is nowadays mainly used indoors, a possible way of expanding the market would be to increase the outdoor use of the material. Here the durability is of great importance, and one important factor is then the capillary characteristics of the material. The thesis therefore focuses on the characterisation of the capillarity in wood for the future improvement of its durability. It is shown that with the material produced by the proposed manufacturing system, i.e. wood with vertical annual rings, the possibility of using hardwood outdoors increases, because the susceptibility to cracking decreases.

  • 38.
    Johansson, Jimmy
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Product differentiation in the Swedish hardwood sawmill industry2005Licentiate thesis, comprehensive summary (Other academic)
  • 39.
    Johansson, Jimmy
    University of Kalmar, Department of Technology.
    The Swedish hardwood sawmill industry: Structure present status and development potential2008In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 3, no 3/4, p. 94-101Article in journal (Refereed)
    Abstract [en]

    This study describes the Swedish hardwood sawmill industry with respect to its structure, raw material, production and market conditions in order to seek ways of increasing the competitiveness of the industry. Fifteen sawmills were studied through observations and interviews. The Swedish hardwood sawmill industry creates job opportunities in sparsely populated areas and uses a biological raw material which is important for environmental biological diversity. Any decrease in the use of this material will mean a drop in the incentive for forest owners to cultivate deciduous forests. Today, the hardwood sawmill industry is experiencing problems in securing the supply of raw material of the desired quality, i.e. without knots and discoloured heartwood (red-heart or brown-heart). To increase the competitiveness of the Swedish hardwood sawmill industry, the raw material supply must be secured. Production should be geared towards products demanded by the market, and new markets need to be entered.

  • 40.
    Johansson, Jimmy
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Blom, Åsa
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Dvinskikh, Sergey
    KTH Royal Institute of Technology.
    NMR-measurements for determination of local moisture content of coated wood2013In: JCT Research, ISSN 1547-0091, E-ISSN 2168-8028, Vol. 10, no 5, p. 601-607Article in journal (Refereed)
    Abstract [en]

    Local increased moisture content (MC) in wood constructions may result in different kinds of mechanical and, especially, biological degrading problems. Therefore, it is of great importance to control the MC of the material. However, there is at present no appropriate method for determining local MC in wood without destroying the product itself. Nondestructive measurements of local MC in wood is significant for the possibility of, for instance, monitoring the in situ MC in wood constructions over time, and thereby predicting potential problems. The nuclear magnetic resonance (NMR) technique has been shown to be valuable for the measurement of MC in wood. In this study, the possibility of utilizing this technique for local MC measurement in wood has been tested on wood samples exposed to water absorption for 72 h. The samples came from three different wood species treated with paint systems available on the market. In the wood samples an artificial “crack” had been created in the paint to introduce an area where the water could easily gain access to the wood. The results show the possibility of using the NMR technique for local MC measurements in wood. The measurement area, however, must be related to the properties of the material. In the case of wood, the measurement spot must be related to the early/latewood proportions. Further, a calibration of the NMR measurement must be made in relation to the expected density variations of the material.

  • 41.
    Johansson, Jimmy
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Blomqvist, Lars
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Nilson, Henrietta
    Linnaeus University, School of Business and Economics, Department of Organisation and Entrepreneurship.
    Landscheidt, Steffen
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Influencing factors to enable automation of wood furniture production2016In: Proceedings of the 12th meeting of the Northern European Networkfor Wood Science and Engineering (WSE): Wood science andengineering – a key factor on the transition to Bioeconomy / [ed] Bruno Andersons and Arnis Kokorevics, Riga, Latvia: Latvian State Institute of Wood Chemistry , 2016, p. 208-213Conference paper (Refereed)
    Abstract [en]

    The wood furniture industry in Sweden has an identified need of technological development in order to stay competitive. Especially the necessity to focus on automation has been identified. In the industry there are often needs to handle large levels of customization at the same time as keeping the production effective. This requires flexible automation solutions, often described as automated equipment that can rapidly be reconfigured for new products.Before automated applications are implemented in an industry there are issues to solve related to organisational, human and technological aspects. Based on this, the project - Flexible automation in manufacturing of laminated veneer products was initiated. The project is running since January 1, 2016 and is a two year national Swedish project. The aim of the project is to investigate challenges concerning automation in the wood furniture industry and especially focusing on bended laminated veneer products.In the project a case-study with the aim of identifying factors important for successful automation implementation in an involved wood manufacturing industry was performed. Key persons and staff of the company were asked to tell their life stories and a process mapping of the production was conducted.The results indicate a problematic relation between the management and the production staff, which partly can be referred to the shift from a family business to a private owned firm. Based on the process mapping, internal transport and handling are identified improvement areas. Productivity is disturbed by stops caused by processing residues and poorly defined materials. There is potential for improvement by adapting a process-oriented approach and defining the materials used.The case–study confirms the need to consider organizational and human aspects in production before initiating production. The study concludes the need to consider the special aspects of the wood material in production development.

  • 42.
    Johansson, Jimmy
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Blomqvist, Lars
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sandberg, Dick
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Challenges using dielectric heating for THM processing of solid wood2013In: Evaluation, processing and predicting of THM treated wood behaviour by experimental and numerical methods / [ed] Carmen-Mihaela Popescu and Maria-Cristina Popescu, Iasi, Romania, 2013, p. 55-56Conference paper (Refereed)
  • 43.
    Johansson, Jimmy
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Skog och Trä.
    Gustafsson, Åsa
    Växjö University, Faculty of Humanities and Social Sciences, School of Management and Economics.
    Improved Ecoeffectiveness of interior hardwood products in the house-building industry as a way to promote sustainable forestry2007In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 2, no 1, p. 22-32Article in journal (Refereed)
    Abstract [en]

    Sawn hardwood is required by the market to be homogeneous, even in texture and colour, but the products produced by Swedish hardwood sawmills exhibit a wide variation in characteristics. This makes it difficult for hardwood sawmills to find profitable markets for all their products. By developing new products with other properties for the building industry it may be possible to utilize hardwood more efficiently and increase the prices. This would result in higher ecoeffectiveness (defined as value in relation to environmental impact) of the forest-related business system by giving an incentive to grow deciduous forests, which leads to richer biological diversity. Diversity is fundamental to achieving sustainable forestry. At the same time, other less ecoefficient materials in buildings may be replaced. Exploring the requirements of the customers is essential before developing new products, in order to maximize the value of a product. In this study, the requirements of interior hardwood products in the Swedish house-building industry were studied in interviews and through questionnaires. The most important requirements, ranked higher than price, are delivery on time, shape stability, packaged products, rapid delivery and accurate moisture content. The results make it possible to focus on critical factors to gain market shares for hardwood as an ecoeffective building material.

  • 44.
    Johansson, Jimmy
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Kifetew, Girma
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    CT-scanning and modelling of the capillary water uptake in aspen, oak and pine2010In: European Journal of Wood and Wood Products, ISSN 0018-3768, Vol. 68, no 1, p. 77-85Article in journal (Refereed)
  • 45.
    Johansson, Jimmy
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Salin, Jarl-Gunnar
    Application of percolation modelling on end-grain water absorption in aspen (Populus tremula L.)2011In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 6, no 3, p. 112-118Article in journal (Refereed)
  • 46.
    Johansson, Jimmy
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sandberg, Dick
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Automatic sorting of sawn birch: Defect detection possibilities on sawn and planed wood surfaces2010In: Hardwood research and utilisation in Europe: New Challanges / [ed] Robert Nemeth and Alfred Teischinger, Sopron: University of West Hungary Press , 2010, p. 206-213Conference paper (Refereed)
    Abstract [en]

    In the production of sawn hardwood a critical processing step is the quality grading. The grading has normally been handled manually in the hardwood sawmills. The process has been labour intensive and a problematic working environment. With the help from existing scanning technology it is possible to automate the process with several benefits as a result. These are e.g. a decreased need of labour, a better working environment and the possibility to use more complicated grading rules. Thereby the wood could be used in a more optimal way with both cost and environmental benefits.

    One problem when grading hardwood is that camera and laser based scanning technology has mainly been used on planed surfaces. Normally the quality grading in hardwood sawmills is performed before planing. The wood may then be cross-cutted to components before planing in order to minimise the volume losses because of deformations of the wood pieces.

    In order to investigate the possibilities to scan the sawn wood before planing rip-sawn birch boards (Betula pubescens Ehrh., Betula pendula Roth.) was scanned before and after planing the wood. The used scanner was a commercial system for automatic sorting of wood. Before the scanning it was estimated that the sawn surfaces exposed to the surrounding environment during drying would not generate any usable results from the scanning. Therefore only the two rip-sawn surfaces were used for evaluation before and after planing. The evaluation was made by comparing the results from the quality grading before and after the planing based on grading rules used by Swedish hardwood sawmill. The results show that there are possibilities to grade the birch wood before planing. The study, however, shows that the scanner has difficulties in detecting small colour variations as brown streaks and fresh knots. It is also difficult to detect fibre angle deviations because of loose fibres on the sawn surface. The possibilities to scan the birch wood are thereby related to the grading rules, i.e. if the mentioned quality parameters are allowed or not.

  • 47.
    Johansson, Jimmy
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sandberg, Dick
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Improved use and production of hardwood with the PrimWood Method2010In: Broadleaved forests in southern Sweden: management for multiple goals / [ed] Magnus Löf , Jörg Brunet, Leif Mattsson och Mats Nylinder, Oxford: Wiley-Blackwell, 2010, Vol. 53, p. 51-59Chapter in book (Refereed)
  • 48.
    Johansson, Jimmy
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sandberg, Dick
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology. Luleå University of Technology.
    Integrated use of product data for improved wood material utilization in the furniture and joinery production2013In: Pro Ligno, ISSN 1841-4737, E-ISSN 2069-7430, Vol. 9, no 4, p. 321-327Article in journal (Refereed)
    Abstract [en]

    Quality communication from customer to supplier is crucial for the effectiveness of a value chain. In the forest products industry, a mutual understanding of quality requirements between customer and supplier in relation to material characteristics and production conditions is important if the material is to be utilized effectively.

     

    In the mechanical wood industry, hardwood has normally been quality graded manually. This has been a work-intensive operation and a problematic working environment. Automatic grading equipment based mainly on camera and laser technology is therefore gradually replacing the manual grading operation which relies on the human eye. The cross-cutting of sawn wood into shorter components with well-defined quality parameters is a process which needs to be automated. This makes it possible for the sawmill to redefine the quality grading process with e.g. more complex grading rules. To gain full benefits from the new technology, however, the grading process must be redefined in cooperation with the customers. There is also an expressed need for tools to communicate the quality of products produced by sawmills.

     

    In this study, three case studies were therefore performed where the communication of requirements between sawmills and customers was studied with regard to three different components delivered from two sawmills. In one sawmill, two products were studied; one intended for a furniture producer and one for a joinery producer. In the other sawmill, the studied product was intended for a producer of solid wood panels. The idea has been to study the need for product information expressed by both the customer and supplier through the automatic grading process and to utilise this equipment for data collection and visualisation.

     

    The requirements for a communication and data exchange tool have been derived. There is often an expressed need to measure how different raw materials affect the volume yield in a process and how different quality requirements affect the volume yield. Sharing this information between customer and supplier has been shown to yield a mutual understanding of how and why deviations occur. Visualisation possibilities are a prerequisite for a mutual understanding of quality conceptions.

  • 49.
    Johansson, Jimmy
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Sandberg, Dick
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Ny träteknik höjer värdet på lövskogen2008In: Ekbladet, ISSN 0283-4839, no 23, p. 24-27Article in journal (Other academic)
    Abstract [sv]

    Lövträ är ett uppskattat material i möbler, snickerier och inredningar samtidigt som en stor del av det svenska lövträet av olika anledningar inte utnyttjas för dessa användningsområden. Endast ca. 5 % av den totala volymen lövträ som årligen avverkas blir sågat virke. Motsvarande siffra för furu och gran är 50 %. Istället importeras den största delen av råvaran, men bakom knuten väntar nya spännande nyheter, vilka är ett  resultat av forskningen vid Växjö universitets avdelning för Skog & Trä.

  • 50.
    Johansson, Jimmy
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Sandberg, Dick
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Preparation of wood with pulsed UV-laser ablation for characterisation of the wood structure2007In: Proceedings of Third International Symposium on Wood Machining, Presses polytechniques et universitaires romandes , 2007, p. 191-194Conference paper (Refereed)
    Abstract [en]

    In contrast to mechanical techniques involving cutting with a knife, cutting with a microtome or grinding, pulsed UV-laser ablation is an irradiation technique where a so-called Excimer laser is used, and the process is adiabatic, which means that no or a very little chemical change occurs in the material being processed. Cross sections of samples of Scots pine and Norway spruce which had been exposed outdoors have been prepared with the help of an Excimer laser (wavelength 248 nm) for study in a microscope. UV-laser ablation has been found to be a suitable method of preparation for wood when it is desired to obtain thin sections with little influence on the material, and particularly when dealing with brittle materials, e.g. archaeological wood, biologically-attacked wood or, as in this case, wood which has been exposed outdoors.

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