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  • 1.
    Achtel, Christian
    et al.
    Friedrich Schiller University of Jena, Germany.
    Jedvert, Kerstin
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB. Friedrich Schiller University of Jena, Germany.
    Kosan, Birgit
    Thuringian Institute of Textile and Plastics Research (TITK), Germany.
    Seoud, Omar. A.El
    University of São Paulo, Brazil.
    Heinze, Thomas
    Friedrich Schiller University of Jena, Germany.
    Dissolution capacity of novel cellulose solvents based on triethyloctylammonium chloride2017Ingår i: Macromolecular Chemistry and Physics, ISSN 1022-1352, E-ISSN 1521-3935, Vol. 218, nr 21, 1700208Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dissolution of cellulose from various sources (microcrystalline cellulose and different dissolving grade pulp fibers) is investigated in solvent systems based on triethyl(n-octyl)ammonium chloride (N2228Cl). Clear cellulose solutions are obtained with N2228Cl in a variety of solvents, e.g., dimethyl sulfoxide, N,N-dimethylacetamide, and acetone. It is possible to prepare clear cellulose solutions from pulp fibers with concentrations up to 15 wt%. However, it is found that the cellulose is degraded, especially when neat (i.e., molten) N2228Cl is used as a solvent. The present work includes comprehensive rheological characterization of the cellulose solutions, both with shear and extensional rheology. In most cases, the viscosity values are low (complex viscosities below 100 Pa s for 5–10 wt% dissolved cellulose), and the solutions show more Newtonian than viscoelastic behavior. 

  • 2.
    Adolfsson, Erik
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB, Keramer.
    Zirconia in applications with bone contact2016Konferensbidrag (Övrigt vetenskapligt)
  • 3.
    Adolfsson, Erik
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Lyckfeldt, Ola
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Johansson, Emil
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Visible-Light CurableCeramic Suspensions for Additive Manufacturing of Dense Ceramic Parts2016Konferensbidrag (Övrigt vetenskapligt)
  • 4.
    Adolfsson, Erik
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Shen, J.Z.
    Stockholm University.
    Defect Minimization in Prosthetic Ceramics2014Ingår i: Advanced Ceramics for Dentistry, Elsevier Inc. , 2014, 359-373 s.Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    The mechanical reliability and aesthetic appearance of ceramic dental prostheses are strongly influenced by the presence of defects. When several processes are used during fabrication of ceramic dental prostheses, additional defects are unavoidably introduced in each process step; these are in addition to the ones that already exist in raw materials. To avoid the degeneration of material performance by the accumulated defect population, process optimization is needed to minimize the defects introduced. Standardized mechanical evaluations are usually performed on samples with carefully prepared surfaces in order to minimize the influence from the defects usually induced by fabrication processes. The results from such mechanical evaluation indicate the strength level that is achievable by the material with the given population of bulk defects. In order to avoid a reduction in the performance of the ceramic material by the additional defects normally induced by the fabrication process, it must be understood how these defects are introduced, and solutions must be found to reduce their size and frequency through modifications of the material and processes. The aim of this chapter is to elucidate the sources of defects that are common for ceramic dental prostheses and to determine how to minimize them. © 2014 Elsevier Inc. All rights reserved.

  • 5.
    Adolfsson, Erik
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Shen, Z.
    Stockholm University.
    Effects of granule density on strength and granule related defects in zirconia2012Ingår i: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 32, nr 11, 2653-2659 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A suspension of zirconia powder (TZ3YSE) with a solids loading of 50. vol% was prepared by ball milling. Binders were added and some of the suspension was diluted to 40, 30 and 20. vol% before freeze granulation was performed. A spray dried material (TZ3YSEB) was used as a reference. The pore size distribution of the different granules was evaluated and from the microstructure it was shown that inhomogeneities were present in both the freeze granulated as well as in the spray dried granules. In addition, the density, microstructure as well as the strength of sintered materials prepared from the granules were studied. The results showed that a high green density or sintered density was not sufficient in order to achieve a high strength material. It was further shown that the strength was significantly influenced by the granule density and not by the inhomogeneities found in the granules. © 2012.

  • 6.
    Adolfsson, Erik
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Tönnäng, Lenny
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    The effect of softmachining parameters on the mechanical strength of zirconia2015Konferensbidrag (Övrigt vetenskapligt)
  • 7.
    Adolfsson, Erik
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Venturini, Francesca
    ZHAW School of Engineering.
    Schönherr, Veit
    ZHAW School of Engineering .
    Rey, Julien
    ZHAW School of Engineering.
    Characterization oflight-gas interaction in strongly-scattering nanoporous materials and itsimplications for tunable diode laser absorption spectroscopy2016Konferensbidrag (Övrigt vetenskapligt)
  • 8.
    Ahlström, Johan
    RISE, Swerea, Swerea KIMAB AB.
    Aluminium i betong - Litteraturstudie och experimentella försök2012Rapport (Refereegranskat)
    Abstract [sv]

    I dagens byggprojekt används en mängd olika material för att bygga konstruktioner. Det förekommer att komponenter av aluminium gjuts in i betong vilket medför en risk att täckskiktet spricker p.g.a. korrosionsprodukternas stora volym. Därför är det viktigt att klargöra vilka korrosionsegenskaper aluminium har ingjuten i betong.

  • 9.
    Ahlström, Johan
    RISE, Swerea, Swerea KIMAB AB.
    Atmosfäriska korrosionsegenskaper för rostfritt stål med olika ytstruktur2011Rapport (Refereegranskat)
    Abstract [sv]

    Generellt sett så har rostfria stål en hög korrosionsresistens i atmosfärisk miljö p.g.a. den mycket tunna oxidfilmen på ytan, en film som fungerar som en barriär och försvårar initieringen av en korrosionsprocess på stålets yta. Dock så kan rostfria stål få svåra gropfrätningsangrepp i vissa aggressiva atmosfärer där t.ex. klorider och SO2 finns närvarande. Olika ytstrukturer kan ge ytan olika egenskaper som vätbarhet, ytråhet och ytsammansättning. En yta som har hög vätbarhet har en tjockare fuktfilm på ytan jämfört med en yta som har låg vätbarhet. Det är i fuktfilmen på ytan som korrosionsprocesserna sker, aggressiva partiklar och gaser kan tas upp i fuktfilmen från atmosfären och öka korrosionshastigheten. Ytråheten påverkar både vätbarhet och hur mycket partiklar som fastnar på en yta, därmed påverkar ytråheten korrosionshastigheten. Ytsammansättning anger vilka och hur mycket det finns av ett ämne i den skyddande oxidfilmen, ämnen som kan ha betydelse för hur lätt korrosion uppstår, t.ex. så kan olika sulfider fungera som initieringsyta för korrosionsangrepp. I litteraturen har det dragits olika slutsatser om vilken ytegenskap som har störst betydelse för korrosionens omfattning. Vissa studier säger att ytråheten har störst betydelse medan andra säger att ytsammansättningen har störst betydelse. Särskilt låglegerade ferritiska rostfria stål kan få svår gropfrätning i aggressiva miljöer och då har typen av ytstruktur liten betydelse för hur stora korrosionsangreppen blir. För de mer legerade austenitiska stålen kan typen av ytstruktur ha stor betydelse för storleken på korrosionsangrepp. Höglegerade stål som innehåller molybden har generellt sett små korrosionsangrepp och typen av ytstruktur har liten betydelse för korrosionsangreppens omfattning. Sammantaget tycks det dock vara så att ytråheten ändå har relativt stor inverkan på korrosionsresistensen, dock har relativt få studier genomförts där ytråheten verkligen mätts.

  • 10.
    Ahlström, Johan
    RISE, Swerea, Swerea KIMAB AB.
    Rostfritt stål i betong med hög fukt och kloridhalt - Provningsmetod för rostfritt stål i betong: Delrapport IV2011Rapport (Refereegranskat)
    Abstract [sv]

    För betongkonstruktioner som är exponerade i aggressiva miljöer kan korrosionsskador uppstå som kräver kostsamma reparationer. Aggressiva miljöer kan t.ex. vara konstruktioner i kontakt med havsvatten där klorider kan transporteras genom betongskiktet fram till armeringen och där orsakar korrosionsskador. För att förhindra vissa korrosionsskador kan armering av kolstål (som är det vanligaste armeringsmaterialet) bytas ut mot armering i rostfritt stål. Idag finns en mängd olika rostfria stål, med olika korrosionsegenskaper, tillgängliga på marknaden och det är därför viktigt att kunna klassificera korrosionshärdigheten för dessa stål. I en tidigare litteraturstudie ”Elektrokemiska metoder för utvärdering av armeringskorrosion samt kritisk kloridjonkoncentration för rostfritt stål i betong” [1] så undersöktes vad som har rapporterats i litteraturen om provningsmetoder för att undersöka korrosionshärdigheten för rostfritt stål i betong. Det framgick av litteraturstudien att en potentiostatisk metod med polarisering till +200 mV kan vara lämplig. I denna studie har en liknande potentiostatisk metod tillämpats och utvärderats. Provkropparna placerades i ett vattenbad där temperaturen ökade med 5°C per 14 dagar från lägst 20°C till maximalt 40°C. Två austenitiska och tre duplexa stål har undersökts och resultaten visar att stålen EN 1.4301 (304), EN 1.4162 (2101), EN 1.4436 (316) fick korrosionsangrepp vid 4 vikt-% Cl per cementvikt när temperaturen på vattenbadet var mellan 20 och 30°C. Det mer legerade duplexa stålet EN 1.4362 (2304) fick korrosionsangrepp vid 6 vikt-% Cl per cementvikt vid en temperatur på 35°C. Det högst legerade stålet EN 1.4462 (2205) fick inga korrosionsangrepp vid10 vikt-% Cl per cementvikt som var den högsta kloridkoncentrationen.

  • 11.
    Ahlström, Johan
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Tidblad, Johan
    RISE, Swerea, Swerea KIMAB AB.
    Sandberg, Bertil
    RISE, Swerea, Swerea KIMAB AB.
    Wadsö, L.
    Lund University.
    Galvanic corrosion properties of steel in water saturated concrete2015Ingår i: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 66, nr 1, 67-75 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aluminum-based sacrificial anodes were installed to reinforced concrete to stop ongoing corrosion in cooling water tunnels in a Swedish nuclear power plant. The steel rebars were also unintentionally connected to stainless steel water pumps. Therefore, the consumption rate of the sacrificial anodes was higher than predicted. An experimental and a field study were performed to assess if the steel rebar suffer from galvanic corrosion and if the stainless steel pumps are responsible alone for the high consumption rate. It was found from the experimental study that there is an increased risk of galvanic corrosion for steel rebar when the corrosion potential is raised to -200mV (SCE) for samples with 1% CL- by mass of cement and -500mV (SCE) for samples with 2% Cl- by mass of cement. The experimental results were compared with the corrosion potential measured in the cooling water tunnel where sacri ficial anodes were in use and not mounted at all. The cooling water tunnel without sacrificial anodes had generally more anodic corrosion potentials compared to the tunnel with anodes. The tunnel with anodes had also more anodic potentials closer to the stainless steel pumps than further away which means that the rebar is affected by the stainless steel pumps. However, the measured corrosion potentials in the tunnels were not as anodic as the potentials needed for high galvanic current measured in the experimental study. © 2013 Wiley-VCH Verlag GmbH & Co. KGaA.

  • 12.
    Aitomäki, Y.
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Hagström, Bengt
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Långström, R.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Fernberg, P.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Novel reactive bicomponent fibres: Material in composite manufacturing2012Ingår i: Journal of Nanostructured Polymers and Nanocomposites, ISSN 17904439, Vol. 8, nr 1, 11-maj s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The hypotheses that reactive uncured, thermoset bicomponent fibres can be prepared and mixed with reinforcing fibres and ultimately used in preparation of a composite was tested and is described. It is thought that such fibres have the two potential advantages: (1) to enable manufacturing with particle doped resins e.g. nanocomposites which add functionality to composites and (2) increased efficiency of structural composite manufacturing by increasing the level of automation. The structure of the thermoset fibres comprises of a sheath of thermoplastic and a core of uncured thermoset resin. Once manufactured, the fibres were wound with a reinforced fibre onto a plate, consolidated and cured. The resulting composite was examined and compared to other composites made with the same manufacturing method from commercially available materials. The results show that a laminate can be produced using these reactive bicomponent fibres. The resin system successfully impregnates the reinforcing carbon fibres and that the thermoplastic separates from the epoxy resin system during consolidation. In comparison to reference material, the bicomponent laminate shows promising characteristics. However, the processes developed are currently on a lab-scale and considerable improvement of various bicomponent fibre properties, such as the strength, are required before the technology can be used on a larger scale.

  • 13.
    Aitomäki, Yvonne
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Hagström, Bengt
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Långström, Runar
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Fernberg, Patrik
    RISE - Research Institutes of Sweden, Swerea, Swerea SICOMP AB.
    Novel reactive bicomponent fibres: Material in composite manufacturing2012Ingår i: Journal of Nanostructured Polymers and Nanocomposites, ISSN 17904439, Vol. 8, nr 1, s.5-11 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The hypotheses that reactive uncured, thermoset bicomponent fibres can be prepared and mixed with reinforcing fibres and ultimately used in preparation of a composite was tested and is described. It is thought that such fibres have the two potential advantages: (1) to enable manufacturing with particle doped resins e.g. nanocomposites which add functionality to composites and (2) increased efficiency of structural composite manufacturing by increasing the level of automation. The structure of the thermoset fibres comprises of a sheath of thermoplastic and a core of uncured thermoset resin. Once manufactured, the fibres were wound with a reinforced fibre onto a plate, consolidated and cured. The resulting composite was examined and compared to other composites made with the same manufacturing method from commercially available materials. The results show that a laminate can be produced using these reactive bicomponent fibres. The resin system successfully impregnates the reinforcing carbon fibres and that the thermoplastic separates from the epoxy resin system during consolidation. In comparison to reference material, the bicomponent laminate shows promising characteristics. However, the processes developed are currently on a lab-scale and considerable improvement of various bicomponent fibre properties, such as the strength, are required before the technology can be used on a larger scale.

  • 14.
    Akesson, D.
    et al.
    University of Borås.
    Skrifvars, M.
    University of Borås.
    Walkenström, Pernilla
    RISE, Swerea, Swerea IVF AB.
    Preparation of thermoset composites from natural fibres and acrylate modified soybean oil resins2009Ingår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 114, nr 4, 2502-2508 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Structural composites with a high content of renewable material were produced from natural fibres and an acrylated epoxidized soybean oil resin. Composites were prepared by spray impregnation followed by compression moulding at elevated temperature. The resulting composites had good mechanical properties in terms of tensile strength and flexural strength. Tensile testing as well as dynamical mechanical thermal analysis showed that increasing the fibre content, increased the mechanical properties. The resin can be reinforced with up to 70 wt % fibre without sacrifice in processability. The tensile modulus ranged between 5.8 and 9.7 GPa depending on the type of fibre mat. The study of the adhesion by low vacuum scanning electron microscopy shows that the fibres are well impregnated in the matrix. The aging properties were finally evaluated. This study shows that composites with a very high content of renewable constituents can be produced from soy bean oil resins and natural fibres. © 2009 Wiley Periodicals, Inc.

  • 15.
    Alberts, D.
    et al.
    University of Oviedo.
    Vega, V.
    University of Oviedo.
    Pereiro, R.
    University of Oviedo.
    Bordel, N.
    University of Oviedo.
    Prida, V.M.
    University of Oviedo.
    Bengtson, Arne
    RISE, Swerea, Swerea KIMAB AB.
    Sanz-Medel, A.
    University of Oviedo.
    In-depth profile analysis of filled alumina and titania nanostructured templates by radiofrequency glow discharge coupled to optical emission spectrometry2010Ingår i: Analusis, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 396, nr 8, 2833-2840 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of highly ordered and self-assembled magnetic nanostructures such as arrays of Fe or Ni nanowires and their alloys is arousing increasing interest due to the peculiar magnetic properties of such materials at the nanoscale. These nanostructures can be fabricated using nanoporous anodic alumina membranes or self-assembled nanotubular titanium dioxide as templates. The chemical characterization of the nanostructured layers is of great importance to assist the optimization of the filling procedure or to determine their manufacturing quality. Radiofrequency glow discharge (RF-GD) coupled to optical emission spectrometry (OES) is a powerful tool for the direct analysis of either conducting or insulating materials and to carry out depth profile analysis of thin layers by multi-matrix calibration procedures. Thus, the capability of RF-GD-OES is investigated here for the in-depth quantitative analysis of self-aligned titania nanotubes and self-ordered nanoporous alumina filled with arrays of metallic and magnetic nanowires obtained using the template-assisted filling method. The samples analysed in this work consisted of arrays of Ni nanowires with different lengths (from 1.2 up to 5 μm) and multilayer nanowires of alternating layers with different thicknesses (of 1-2 μm) of Ni and Au, or Au and FeNi alloy, deposited inside the alumina and titania membranes. Results, compared with other techniques such as scanning electron microscopy and energy-dispersive X-ray spectroscopy, show that the RF-GD-OES surface analysis technique proves to be adequate and promising for this challenging application. © 2009 Springer-Verlag.

  • 16.
    Albinsson, Ola
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Lundevall, Åsa
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Sehati, Parisa
    Linköpings universitet.
    Stålhanske, Christina
    RISE.
    Sundberg, P
    Mattsson, Lards-Göran
    KTH Royal Institute of Technology .
    Sjövall, Peter
    Rise.
    The influence of surface composition and plasma treatment on adhesion2015Ingår i: Proceedings of GPD Glass Performance Days 2015, 2015, 11-14 s.Konferensbidrag (Övrigt vetenskapligt)
  • 17.
    Alexis, Jonas
    et al.
    RISE, Swerea, Swerea MEFOS AB.
    Björkvall, Johan.
    RISE, Swerea, Swerea MEFOS AB.
    Mathematical modeling of stirring for an optimized ladle furnace process2011Ingår i: AISTech - Iron and Steel Technology Conference Proceedings, 2011, 1389-1399 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    [No abstract available]

  • 18.
    Alipour, Y.
    et al.
    KTH Royal Institute of Technology.
    Talus, Annika
    RISE, Swerea, Swerea KIMAB AB.
    Henderson, P.
    KTH Royal Institute of Technology.
    Norling, Rikard
    RISE, Swerea, Swerea KIMAB AB.
    The effect of co-firing sewage sludge with used wood on the corrosion of an FeCrAl alloy and a nickel-based alloy in the furnace region2015Ingår i: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of digested sewage sludge as a fuel additive to reduce corrosion of furnace walls has been studied. The nickel base alloy Alloy 625 and the iron-chromium-aluminium alloy Kanthal APMT™ were exposed for 14.25. h at the furnace wall in a power boiler burning 100% used (also known as waste or recycled) wood. The test was then repeated with the addition of sewage sludge to the waste wood. The samples were chemically analysed and thermodynamically modelled and the corrosion mechanisms were investigated. The results showed that the co-firing of sewage sludge with recycled wood leads to a reduction in the corrosion. Attack by a potassium-lead combination appeared to be the main corrosion mechanism in Alloy 625 during waste wood combustion, while attack by alkali chloride was found to be dominant in APMT alloy. © 2015 Elsevier B.V.

  • 19.
    Alipour, Y.
    et al.
    KTH Royal Institute of Technology.
    Viklund, Peter
    RISE, Swerea, Swerea KIMAB AB.
    Henderson, P.
    Vattenfall Research and Development.
    The analysis of furnace wall deposits in a low-NOx waste wood-fired bubbling fluidised bed boiler2012Ingår i: VGB PowerTech, ISSN 14353199, Vol. 92, nr 12, 96-100 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Increasing use is being made of biomass as fuel for electricity production as the price of natural wood continues to rise. Therefore, more use is being made of waste wood (recycled wood). However, waste wood contains more chlorine, zinc and lead, which are believed to increase corrosion rates. Corrosion problems have occurred on the furnace walls of a fluidised bed boiler firing 100 % waste wood under low-NOx conditions. The deposits have been collected and analysed in order to understand the impact of the fuel.

  • 20.
    Allen, D.H.
    et al.
    Texas AandM University.
    Holmberg, Anders
    RISE, Swerea, Swerea SICOMP AB.
    Ericson, M.
    Volvo Car Components Corporation.
    Lans, L.
    Volvo Car Corporation.
    Svensson, N.
    Xdin AB.
    Holmberg, S.
    Volvo Car Components Corporation.
    Modeling the viscoelastic response of GMT structural components2001Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 61, nr 4, 503-515 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A glass-mat-reinforced thermoplastic (GMT) composite material has been fabricated from randomly oriented continuous glass fibers embedded in a polypropylene matrix. The mechanical constitution of this composite has been characterized by using a linear viscoelastic micromechanically based material model. This material model has subsequently been implemented to several finite-element computer codes for analysis of structural components fabricated from polypropylene GMT. In this paper several example problems have been studied in order to determine the applicability of this modeling approach to predicting time-dependent deformations due to creep in GMT components. These example problems have been solved by utilizing two commercially available codes: ABAQUS, and ANSYS. Furthermore, results obtained with the codes have been compared to both analytic and experimental results, with varying degrees of success. The paper details these results for each of the example problems considered herein. © 2001 Elsevier Science Ltd. All rights reserved.

  • 21.
    Allvar, Marie
    RISE, Swerea, Swerea KIMAB AB.
    MIG/MAG brazing with cold metal transfer2012Rapport (Refereegranskat)
    Abstract [en]

    In the automotive industry a commonly used material is thin steel sheets coated with a thin layer of zinc for corrosion resistance purposes. Welding of this material, with the high temperatures involved, causes problems with zinc burn-off leading to reduced corrosion resistance. The zinc evaporation also causes arc disturbances leading to spatter formation, pores and difficulties achieving good visual weld quality. The joints are in many cases visible or semi-visible (e.g. visible after opening a door) and “A-grade” quality is demanded, meaning no visible discontinuities are allowed. It also implies a smooth and generally appealing appearance of the joint. An alternative to welding is brazing, and laser brazing meets the requirements but the process is associated with high costs. In the national project “LEX-B”, funded by Vinnova, the possibilities of using arc brazing, in particular one MIG/MAG brazing and two TIG brazing processes, for some automotive applications are investigated. This master thesis is connected to the first part of the project and aims at compiling data for making a selection of the most promising process to investigate and optimise further. LEX-B is conducted in cooperation between Swerea KIMAB AB, Volvo Trucks, Scania CV and University West. The joint of interest is a lap joint between bottom and upper sheets of 1.2 mm and 0.8 mm respectively that represents a joint on the side of a truck cabin. The requirements are visual A-grade quality and tensile shear strength of 300 MPa. In the project the MIG/MAG process Cold Metal Transfer (CMT) was compared to the TIG processes forceTIG and Plasmatron. CMT was experimentally investigated while the results for the other two processes were obtained partly from a previous study and partly from Volvo Trucks where tests were performed simultaneously. A system for measuring data for the process was developed, test specimens were brazed and examined visually and mechanical destructive testing was performed to ensure the tensile shear strength. Parameter studies were done for further process optimisation.

  • 22.
    Altmann, Brigitte
    et al.
    University of Freiburg .
    Karygianni, Lamprini
    University of Freiburg .
    Al-Ahmad, Ali
    University of Freiburg .
    Butz, Frank
    University of Freiburg .
    Bächle, Maria
    University of Freiburg .
    Adolfsson, Erik
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Fürderer, Tobias
    Courtois, Nicolas
    Palmero, Paola
    Politecnico di Torino.
    Follo, Marie
    University of Freiburg .
    Chevalier, Jérôme
    Université de Lyon.
    Steinberg, Thorsten
    University of Freiburg .
    Kohal, Ralf Joachim
    University of Freiburg .
    Assessment of Novel Long-Lasting Ceria-Stabilized Zirconia-Based Ceramics with Different Surface Topographies as Implant Materials2017Ingår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of long-lasting zirconia-based ceramics for implants, which are not prone to hydrothermal aging, is not satisfactorily solved. Therefore, this study is conceived as an overall evaluation screening of novel ceria-stabilized zirconia-alumina-aluminate composite ceramics (ZA8Sr8-Ce11) with different surface topographies for use in clinical applications. Ceria-stabilized zirconia is chosen as the matrix for the composite material, due to its lower susceptibility to aging than yttria-stabilized zirconia (3Y-TZP). This assessment is carried out on three preclinical investigation levels, indicating an overall biocompatibility of ceria-stabilized zirconia-based ceramics, both in vitro and in vivo. Long-term attachment and mineralized extracellular matrix (ECM) deposition of primary osteoblasts are the most distinct on porous ZA8Sr8-Ce11p surfaces, while ECM attachment on 3Y-TZP and ZA8Sr8-Ce11 with compact surface texture is poor. In this regard, the animal study confirms the porous ZA8Sr8-Ce11p to be the most favorable material, showing the highest bone-to-implant contact values and implant stability post implantation in comparison with control groups. Moreover, the microbiological evaluation reveals no favoritism of biofilm formation on the porous ZA8Sr8-Ce11p when compared to a smooth control surface. Hence, together with the in vitro in vivo assessment analogy, the promising clinical potential of this novel ZA8Sr8-Ce11 as an implant material is demonstrated. 

  • 23.
    Altmann, Brigitte
    et al.
    University Medical Center Freiburg, Freiburg, Germany ; .
    Rabel, Kerstin
    University Medical Center Freiburg, Freiburg, Germany ; .
    Kohal, Ralf J.
    University Medical Center Freiburg, Freiburg, Germany.
    Proksch, Susanne
    University Medical Center Freiburg, Freiburg, Germany.
    Tomakidi, Pascal
    University Medical Center Freiburg, Freiburg, Germany.
    Adolfsson, Erik
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Bernsmann, Falk
    NTTF Coatings GmbH, Rheinbreitbach, Germany.
    Palmero, Paola
    INSTM R.U. PoliTO, LINCE Lab., Politecnico di Torino, Torino, Italy.
    Fürderer, Tobias
    MOESCHTER GROUP Holding GmbH & Co. KG, Dortmund, Germany.
    Steinberg, Thorsten
    University Medical Center Freiburg, Freiburg, Germany.
    Cellular transcriptional response to zirconia-based implant materials2017Ingår i: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 33, nr 2, 241-255 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Objective To adequately address clinically important issues such as osseointegration and soft tissue integration, we screened for the direct biological cell response by culturing human osteoblasts and gingival fibroblasts on novel zirconia-based dental implant biomaterials and subjecting them to transcriptional analysis. Methods Biomaterials used for osteoblasts involved micro-roughened surfaces made of a new type of ceria-stabilized zirconia composite with two different topographies, zirconium dioxide, and yttria-stabilized zirconia (control). For fibroblasts smooth ceria- and yttria-stabilized zirconia surface were used. The expression of 90 issue-relevant genes was determined on mRNA transcription level by real-time PCR Array technology after growth periods of 1 and 7 days. Results Generally, modulation of gene transcription exhibited a dual dependence, first by time and second by the biomaterial, whereas biomaterial-triggered changes were predominantly caused by the biomaterials’ chemistry rather than surface topography. Per se, modulated genes assigned to regenerative tissue processes such as fracture healing and wound healing and in detail included colony stimulating factors (CSF2 and CSF3), growth factors, which regulate bone matrix properties (e.g. BMP3 and TGFB1), osteogenic BMPs (BMP2/4/6/7) and transcription factors (RUNX2 and SP7), matrix collagens and osteocalcin, laminins as well as integrin ß1 and MMP-2. Significance With respect to the biomaterials under study, the screening showed that a new zirconia-based composite stabilized with ceria may be promising to provide clinically desired periodontal tissue integration. Moreover, by detecting biomarkers modulated in a time- and/or biomaterial-dependent manner, we identified candidate genes for the targeted analysis of cell-implant bioresponse during biomaterial research and development.

  • 24.
    Andersons, J.
    et al.
    University of Latvia.
    Sparniņš, E.
    University of Latvia.
    Nyström, Birgitha
    RISE, Swerea, Swerea SICOMP AB.
    Joffe, Roberts
    RISE, Swerea, Swerea SICOMP AB.
    Scale effect of the tensile strength of flax-fabric-reinforced polymer composites2011Ingår i: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 30, nr 23, 1969-1974 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of UD natural fiber composites, considered for application as structural materials, necessitates evaluation of the scale effect of their strength. Alignment of the fibers in flax bast fiber composites can be achieved by employing textile reinforcement, such as yarns and fabrics. Cutting specimens for mechanical tests out of such textile-reinforced composite plates results in a complex non-uniform reinforcement structure at their edges, which may affect the strength of specimens. Scale effect of the tensile strength in the fiber direction of flax-fabric-reinforced composites is studied in the current work. A model accounting for both volume and edge effect of the specimens on their tensile strength is proposed. © The Author(s) 2011.

  • 25.
    Andersson, B.
    et al.
    Aeronautical Research Institute of Sweden.
    Sjögren, Anders
    RISE, Swerea, Swerea SICOMP AB.
    Berglund, L.
    Luleå University of Technology.
    Micro- and meso-level residual stresses in glass-fiber/vinyl-ester composites2000Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 60, nr 10, 2011-2028 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Residual stresses in glass-fiber composites were studied on the micro and meso scales by computational and experimental methods. Transmitted polarized light images of thin sections were compared with 3D finite-element solutions of a sample containing 1410 fibers. Calculated point-wise stresses were derived from a linear thermoelastic model with negligibly small numerical errors. Regions with calculated maximum compressive stresses showed good agreement with experimentally observed optical bands. A material with poor interfacial adhesion showed weaker optical effects indicating fiber/matrix debonding. On the basis of these results it seems likely that irreversible matrix deformation and debonding can take place in the curing phase. (C) 2000 Elsevier Science Ltd. All rights reserved.Residual stresses in glass-fiber composites were studied on the micro and meso scales by computational and experimental methods. Transmitted polarized light images of thin sections were compared with 3D finite-element solutions of a sample containing 1410 fibers. Calculated point-wise stresses were derived from a linear thermoelastic model with negligibly small numerical errors. Regions with calculated maximum compressive stresses showed good agreement with experimentally observed optical bands. A material with poor interfacial adhesion showed weaker optical effects indicating fiber/matrix debonding. On the basis of these results it seems likely that irreversible matrix deformation and debonding can take place in the curing phase.

  • 26.
    Andersson, Dag
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Brinkfeldt, Klas
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Simulations and Fabrication of a SiC-Based Power Module with Double SidedCooling: in Proceedings of the IMAPS Nordic Annual Conference 20152015Konferensbidrag (Övrigt vetenskapligt)
  • 27.
    Andersson, Dag
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Brinkfeldt, Klas
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Nord, S.
    Volvo Group Trucks Technology.
    Ottosson, J.
    Volvo Group Trucks Technology.
    Lampic, G.
    Elaphe Propulsion Technologies Ltd.
    Gotovac, G.
    Elaphe Propulsion Technologies Ltd.
    Zschieschang, O.
    Fairchild Semiconductor GmbH.
    Baumgartel, H.
    Hella Fahrzeugkomponenten GmbH.
    Brusius, M.
    Sensitec GmbH.
    Kaulfersch, E.
    Berliner Nanotest und Design GmbH.
    Hilpert, F.
    Fraunhofer IISB.
    Otto, A.
    Fraunhofer ENAS.
    Frankeser, S.
    Technische Universität Chemnitz.
    COSIVU - Compact, smart and reliable drive unit for fully electric vehicles2016Ingår i: 2016 Pan Pacific Microelectronics Symposium, Pan Pacific 2016Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    COSIVU is a three year collaborative research project that ended in September 2015 and which has been funded within the European Green Car Initiative (now the European Green Vehicle Initiative). COSIVU addresses one of the most critical technical parts in fully electrical vehicles (FEV) besides the energy storage system: the mechatronic drive-train unit. The COSIVU project has delivered a new system architecture for multiple wheel drive-trains by a smart, compact and durable single-wheel drive unit with integrated electric motor, full silicon carbide (SiC) power electronics (switches and diodes), a novel control and health monitoring module with wireless communication, and an advanced ultra-compact cooling solution. DfR utilizing FEM simulations ensures first time right solutions. This paper presents the main results including the architecture of the drive train solution as well as the modular design of the inverter based on Inverter Building Blocks, one per phase. Performance tests are presented here for the first time for both the heavy duty commercial vehicle solution performed in a test rig by Volvo, and the tests of the COSIVU solution adapted to a passenger car done by Elaphe.

  • 28.
    Andersson, Dag
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Carlström, Elis
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Orlenius, Jessica
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Zackrisson, Mats
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Avellán, Lars
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    LCA as a Strategic Tool for Technology Development – Li Ion Battery Case2013Konferensbidrag (Övrigt vetenskapligt)
  • 29.
    Andersson, Dag
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Nilsson, Erik
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Wetter, Göran
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Interconnection of electrically conductive fibersfor application in smart textiles2015Konferensbidrag (Övrigt vetenskapligt)
  • 30.
    Andersson, Dag
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Weiler, Petra
    VDI/VDE Innovation + Technik GmbH, Germany.
    Mayora, Kepa
    IK4-Ikerlan, Spain.
    Kunze, Michael
    Hahn Schickard, Germany.
    Günzler, Rainer
    Hahn Schickard, Germany.
    Karmann, Stephan
    Hahn Schickard, Germany.
    Steinke, Arndt
    CiS Forschungsinstitut für Mikrosensorik GmbH, Germany.
    Winzer, Andreas
    CiS Forschungsinstitut für Mikrosensorik GmbH, Germany.
    Thronicke, Nicole
    CiS Forschungsinstitut für Mikrosensorik GmbH, Germany.
    Vazquez, Patricia
    Tyndall Institute, Ireland.
    Felemban, Shifa
    Tyndall Institute, Ireland.
    Moore, Eric
    Tyndall Institute, Ireland.
    Voirin, Guy
    CSEM SA, Switzerland.
    Scolan, Emmanuel
    CSEM SA, Switzerland.
    Smadja, Rita
    CSEM SA, Switzerland.
    SMARTER-SI - Smart access to manufacturing for Systems Integration2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    The three year EU project SMARTER-SI that started in February 2015 has developed and tested a new production platform for smart systems that offer SMEs and “mid-cap” companies help to manufacture small and medium volumes. The ultimate goal of this project is to test a new concept for small lot production, which we call the Cooperative Foundry Model (CFM). The CFM is tested by combining components or parts of systems (building blocks) already developed by the RTOs involved in the project in so-called Application Experiments (AEs), thereby creating innovative Smart Systems which serve SMEs' product needs. During the first two years, four predefined AEs have been developed that consist of i) a multi-parametric point of care testing (POCT) device, ii) a dew-point measurement system, iii) a CO2 measurement system, and iv) a portable device that can be used to screen water quality.

  • 31.
    Andersson, Oscar
    et al.
    KTH Royal Institute of Technology, Sweden.
    Budak, Nesrin
    KTH Royal Institute of Technology, Sweden.
    Melander, Arne
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB. KTH Royal Institute of Technology, Sweden.
    Palmquist, Niclas
    Volvo Car Corporation, Sweden.
    Experimental measurements and numerical simulations of distortions of overlap laser-welded thin sheet steel beam structures2017Ingår i: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 61, nr 5, 927-934 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Distortions of mild steel structures caused by laser welding were analyzed. One thousand-millimeter U-beam structures were welded as overlap joints with different process parameters and thickness configurations. Final vertical and transverse distortions after cooling were measured along the U-beam. Significant factors, which affect distortions, were identified. Heat input per unit length, weld length, and sheet thickness showed a significant effect on welding distortions. Furthermore, the welding distortions were modeled using FE simulations. A simplified and computationally efficient simulation method was used. It describes the effect of shrinkage of the weld zone during cooling. The simulations show reasonable computation times and good agreement with experiments.

  • 32.
    Andersson, P.
    et al.
    VTT Technical Research Centre of Finland.
    Levén, Jan
    RISE, Swerea, Swerea MEFOS AB.
    Hemming, B.
    Centre for Metrology and Accreditation, Finland.
    Hot rolling tests with steel bars and silicon nitride rolls2009Ingår i: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 209, nr 2, 884-893 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An experimental study was carried out to investigate the possibilities to use rolls made from Si3N4-TiN ceramic composite in hot rolling of steel. The results show that the wear of the ceramic material was lower than the wear of a reference cast iron. The results suggest that the Si3N4-TiN material is beneficial to use in a hot rolling process, on condition that the temperature of the work piece material is held sufficiently high. © 2008 Elsevier B.V. All rights reserved.

  • 33.
    Andersson, Peter
    RISE, Swerea, Swerea KIMAB AB.
    Thermal conductivity of thermosetting composite materials2012Ingår i: ECCM 2012 - Composites at Venice, Proceedings of the 15th European Conference on Composite Materials, European Conference on Composite Materials, ECCM , 2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this work the thermal conductivity, λ, of composite materials is investigated. The experimental results are from the experimental transient hot wire method and the experimental transient plate source method. The measurements are carried out on pure RTM6 epoxy resin and glass fibre and carbon fibre composites. The material is investigated both in its fully cured, pristine shape as well as during curing, consolidation and degradation. The λ-values for pure epoxy, glass fibre composite and material during degradation has been determined.

  • 34.
    Andersson, Peter
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Gotte, Anders
    RISE, Swerea, Swerea SWECAST AB.
    Värmeledningsförmåga hos formmaterial2011Rapport (Refereegranskat)
    Abstract [sv]

    I den första delen av studien tillverkades och bestämdes värmeledningsförmågan för samtliga provkroppar i olika kvarts/fältspatsander från Baskarpsand. Sanderna skiljer sig åt i medelkornstorlek och kornstorleksfördelning. Två olika självhärdande bindemedel, alfaset och furan, användes. I studiens senare del tillverkades och bestämdes värmeledningsförmågan för provkroppar också i sander baserade på andra mineraler. Dessutom undersöktes ytterligare ett bindemedel, nämligen Coldbox. Resultat för Coldbox redovisas i rapporten, då den inte kommer att ingå i någon publikation. Resultaten från de övriga försök kommer att publiceras i en vetenskaplig tidskrift inom något av områdena gjuteriteknik eller mineralogi. För att tillgodose de tilltänka tidskrifternas publiceringsregler, redovisas inte resultaten för dessa i denna rapport.

  • 35.
    Andersson, Roger
    RISE, Swerea, Swerea KIMAB AB.
    Self-pierce riveting through 3 sheet metal combinations2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    One way to reduce the CO2 emissions in automotives is to reduce the weight of the Body-In-White. One easy to achieve the weight reduction is to replace steel sheet materials with Al alloys, which is 3 times lighter. One issue is the joining process, especially with combinations between steel grades and AL alloys. Example of combination of mixed material combinations (Al-steel) might be found in the door structure. The reason is because of the AL alloys worthier crash performance so the automotive manufacturer might want to use crash impact beams made by high strength steels in a AL intensive door structure. The joining process between aluminum and steel are problematic due it's not possible to use traditional spot-welding technologies due to the materials total difference in microstructure characteristics as well thermal properties. To overcome this issue then mechanical as well adhesion joining are frequently used. This paper describes a development process and subsequently analysis of a self-pierce rivet (SPR) process between 3 sheet metal combinations. The multi-material combinations in this study were a combination of ultra high strength steels sheets (DP1000) and a Al-alloy (AA 6014). The analysis of the SPR process, in sense of mechanical strengths, has been done by peel-and shear tests. To reduce the amount of future physical tests a virtual FE-model has been developed for the process. This FE model of the process has been subsequently used to analyze the mechanical strength during plastic deformation. By using inverse analysis a correct contact algorithm has been evaluated that would predict the binding force between the rivet and sheet under a deformation process. With this new virtual model it will not only possible to analyze and develop the SPR process but also to achieve the final strength of the joint. © 2011 American Institute of Physics.

  • 36.
    Andersson, Stig Peter
    RISE, Swerea, Swerea KIMAB AB.
    Thermal conductivity of powders used in continuous casting of steel part 2: Powders2015Ingår i: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 42, nr 6, 465-470 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Measurements of the thermal conductivity of casting powders are needed to determine the magnitude of the vertical heat flux in the powder bed of a continuous casting mould. The thermal conductivities and thermal diffusivities of four mould powders have been determined using the transient plane source (TPS) and the transient hot wire (THW) methods. The values reported in this investigation are in good agreement with the results of earlier studies which used the THW method. However, the results were significantly different from λeff values obtained in thermal insulation tests. This was attributed to the large contribution to λeff from gaseous conduction which arises from the large temperature gradient across the sample. It was found that the thermal conductivity (λpowd) of the powders had a mean value of 0.125±0.025 W m-1 K-1 for the four powders studied; this value is in good agreement with two other studies; it increased as the temperature increased with a mean temperature coefficient of (dλ/dT59×10-5 W m-1 K-2 for the range 295-1100 K and increased as the bulk density increased (λ295=0.010+1.69×10-4ρbulk W m-1 K-1). © 2015 Institute of Materials, Minerals and Mining.

  • 37.
    Andersson, Stig Peter
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Eggertson, Christer
    RISE, Swerea, Swerea KIMAB AB.
    Thermal conductivity of powders used in continuous casting of steel part 1: Glassy and crystalline slags2015Ingår i: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 42, nr 6, 456-464 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Measurements of the thermal conductivity (λ) and thermal diffusivity (α) have been carried out on samples of Na2O·SiO2 and four mould slags for temperatures between 295 and 1300 K. These measurements were carried out using the transient plane source (TPS) method (295-373 K) and the transient hot wire (THW) technique (295-1300 K) and the laser pulse (LP) or laser flash method in the case of Na2O·SiO2 Values of l295 were very similar (1.07±0.03 W m-1 K-1) and all samples exhibited a maximum at the critical temperature (Tcrit 51040±10 K) beyond which there was a sharp drop in λTHW with increasing temperature. Measurements were also carried out on semi-crystalline samples with increasing λ and fraction of crystalline phase. These samples also exhibited a sharp drop in the thermal conductivity for temperatures above Tcrit and λTcrit was found to be 1.6±0.05 W m-1 K-1. Thermal conductivity (λLP) values calculated from reported thermal diffusivity (αLP) values were in very good agreement with the measured λTHW values for temperatures between 295 K and Tcrit but λLP values did not decrease with increasing temperature above Tcrit (cf. λTHW). Consequently, it was found that λLP≈7λTHW for mould slags. © 2015 Institute of Materials, Minerals and Mining.

  • 38. Anderud, J
    et al.
    Abrahamsson, P
    Jimbo, R
    Isaksson, S
    Adolfsson, Erik
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Malmström, J
    Naito, Y
    Wennerberg, A
    Guided bone augmentation using ceramic space-maintaining devices: The impact of chemistry2015Ingår i: Clinical, Cosmetic and Investigational Dentistry, ISSN 11791357, Vol. 7, 45-53 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The purpose of the study was to evaluate histologically, whether vertical bone augmentation can be achieved using a hollow ceramic space maintaining device in a rabbit calvaria model. Furthermore, the chemistry of microporous hydroxyapatite and zirconia were tested to determine which of these two ceramics are most suitable for guided bone generation. 24 hollow domes in two different ceramic materials were placed subperiosteal on rabbit skull bone. The rabbits were sacrificed after 12 weeks and the histology results were analyzed regarding bone-to-material contact and volume of newly formed bone. The results suggest that the effect of the microporous structure of hydroxyapatite seems to facilitate for the bone cells to adhere to the material and that zirconia enhance a slightly larger volume of newly formed bone. In conclusion, the results of the current study demonstrated that ceramic space maintaining devices permits new bone formation and osteoconduction within the dome. © 2015 Anderud et al.

  • 39.
    Anderud, J.
    et al.
    University Malmö.
    Jimbo, R.
    University Malmö.
    Abrahamsson, P.
    Region Halland.
    Adolfsson, Erik
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF AB.
    Malmström, J.
    Region Halland.
    Wennerberg, A.
    Malmö University.
    The impact of surface roughness and permeability in hydroxyapatite bone regeneration membranes2015Ingår i: Clinical Oral Implants Research, ISSN 0905-7161, E-ISSN 1600-0501Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: One of the crucial aspects in guided bone regeneration is the space maintenance. This is normally created by a membrane, which should primarily be accepted by the surrounding tissues without causing any adverse reactions. The impact of surface topography, biological acceptance as well as permeability of these membranes has been carefully discussed in the literature. Purpose: The purpose of this study was to evaluate histologically the bone forming properties inside of hollow hydroxyapatite space-maintaining devices with different inner surfaces and different permeabilities in an animal calvaria model in vivo. Materials and methods: A total of 36 hollow domes with three different designs made of hydroxyapatite were surgically attached to the skulls of rabbits. Group 1 had a moderately rough inner surface. Group 2 had a smooth inner surface. Group 3 had the same properties as Group 1 but had macroscopic holes on the top. The domes were left to heal for 12 weeks and were then processed for undecalcified ground sectioning. Histological evaluations were performed using a light microscope and scanning electron microscopy. The bone-implant contact (BIC) percentage along the device was calculated. Results: The median percentage of BIC was higher for Group 1 compared with Group 2 (P = 0.004). Group 1 produced a larger median BIC compared with Group 3 (P < 0.0001). Conclusions: Within the limits of this preclinical study, these findings suggest that a moderately rough inner surface of a ceramic membrane along with a non-permeable device produces more bone than a smooth inner surface. © 2015 John Wiley & Sons A/S.

  • 40.
    André, Alann
    RISE, Swerea, Swerea SICOMP AB.
    Utilization of National Instrument equipment for strain and load measurement recording2013Rapport (Refereegranskat)
  • 41.
    André, Alann
    et al.
    RISE, Swerea, Swerea SICOMP AB.
    Haghani, R.
    Chalmers University of Technology.
    Biel, A.
    University of Skövde.
    Application of fracture mechanics to predict the failure load of adhesive joints used to bond CFRP laminates to steel members2012Ingår i: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 27, nr 1, 331-340 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of bolted or welded elements to upgrade metallic structures has been a common practice for many years. Moreover, the use of adhesively bonded carbon fiber reinforced polymer (CFRP) laminates, as an alternative method, has attracted a great deal of attention in recent years. One important aspect of the design of adhesive joints used to bond CFRP laminates to steel substrates is the determination of the properties of the CFRP/adhesive/steel interfaces, which have not yet been established in codes or standards. The purpose of this paper is experimentally to determine the fracture properties of the adhesive material and to evaluate the accuracy of numerical methods using this information, in order to predict the strength of adhesive joints in steel members bonded with CFRP laminates. The results from four series of experimental tests are compared with numerical results and discussed in terms of load-bearing capacity and failure modes. © 2011 Elsevier Ltd. All rights reserved.

  • 42.
    André, Alann
    et al.
    RISE, Swerea, Swerea SICOMP AB.
    Johnsson, H.
    Luleå Univ. of Technology.
    Flax fiber-reinforced glued-laminated timber in tension perpendicular to the grain: Experimental study and probabilistic analysis2010Ingår i: Journal of materials in civil engineering, ISSN 0899-1561, E-ISSN 1943-5533, Vol. 22, nr 9, 827-835 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The weak mechanical properties of wood in tension perpendicular to the grain are often the origin of catastrophic brittle failure. In order to enhance the tension strength perpendicular to the grain and achieve a more ductile failure, flax fiber and glass fiber-reinforced polymer (FRP) composites were used to strengthen glue-laminated (glulam) timber specimens. Three series of specimen of glulam timber (flax fiber reinforced, glass fiber reinforced, and unreinforced), with a grand total of 28 specimens, were tested in tension perpendicular to the grain. For an approximate amount of FRP reinforcement of 1.2% in volume (thickness of ∼0.7 mm), an increase of the tensile strength of up to 74% was shown, with a stiffness increase of up to 41%. For all reinforced specimens, semiductile failures were observed. A parametric study was carried out using both the Monte Carlo (MC) method and the first-order second moment (FOSM) method. It is shown that the mean values obtained during experiments are in agreement with those from the MC simulation. However, the standard deviations from the MC simulation are larger. From the FOSM analysis, it is demonstrated that the variation in glulam stiffness perpendicular to the grain is not the first parameter driving the variation for the reinforced system. The variation in mechanical properties of the flax fibers appeared to be the driving parameter for the strength of the system. © 2010 ASCE.

  • 43.
    André, Alann
    et al.
    RISE, Swerea, Swerea SICOMP AB.
    Kliger, R.
    Chalmers University of Technology.
    Asp, Leif
    RISE, Swerea, Swerea SICOMP AB.
    Compression failure mechanism in small scale timber specimens2014Ingår i: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 50, 130-139 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Understanding the failure mechanism of wood loaded in compression parallel to the grain has been shown to be an important parameter in the design of timber beams strengthened with fibre-reinforced plastics (FRP). In this paper, a constitutive relationship for wood under uniaxial compression load parallel to the grain was determined experimentally. Several parameters, such as silviculture, moisture content and radial position in the log in relation to the pith from where the specimen was sawn, were considered. Small clear-wood specimens were used. The strain localisation in the failure region (kinkband) was monitored using the digital image correlation method. The results show that silviculture and moisture content are two very important parameters which influence the compression failure mechanism. Furthermore, there is a significant difference in behaviour between specimens from the juvenile region of the log and specimens from mature wood. Based on experimental results, two numerical models were built, considering either a global or a local constitutive relationship. It was demonstrated that both numerical models yield accurate results and that, depending on the experimental equipment available, a constitutive relationship could be extracted and used as input in these numerical models. © 2013 Elsevier Ltd. All rights reserved.

  • 44.
    André, Alann
    et al.
    RISE, Swerea, Swerea SICOMP AB.
    Kliger, R.
    Chalmers University of Technology.
    Haghani, R.
    Chalmers University of Technology.
    Timber reinforced FRP: Compression failure mechanism2012Ingår i: Proceedings of the 6th International Conference on FRP Composites in Civil Engineering, CICE 2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    When it comes to strengthening, structural timber engineering has seen polymer composite materials becoming key materials over the last decades. A great number of studies have already shown that the majority of the results were promising. Several strengthening systems applied to structural timber or glued-laminated timber beams revealed that the ultimate failure mode remains in tension regardless of the reinforced system. However, the collapse can be controlled and postponed by optimising the strengthening system. It has been shown that strengthening timber on the tension and compression side simultaneously increases the stiffness and moment capacity more than if the reinforcement was only positioned on the tension side. This is mainly due to the ductility of wood in compression which is fully utilised when strengthening is located on both sides. The main objective behind this study is to develop an experimental method to determine the compressive behaviour of small clear timber specimens reinforced with CFRP.

  • 45.
    André, Alann
    et al.
    RISE, Swerea, Swerea SICOMP AB.
    Kliger, R.
    Chalmers University of Technology.
    Olsson, Robin
    RISE, Swerea, Swerea SICOMP AB.
    Compression failure mechanism in small-scale wood specimens reinforced with CFRP: An experimental study2013Ingår i: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 41, 790-800 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The optimal use of Carbon Fibre Reinforced Polymer (CFRP) when strengthening timber beams loaded in bending involves considering placing the reinforcement on both the tension and the compression side, in order to utilise the ductile compression failure of the wood to the full. In this respect, a knowledge and understanding of the compression failure mechanism of the timber/CFRP system becomes a point of paramount importance. However, no testing method specific to the compression loading of small wood specimens reinforced with CFRP is currently available. This investigation focuses on the experimental developments of the geometry and test set-up necessary in order to determine the compression failure mechanism of small wood block specimens reinforced with CFRP loaded in compression parallel to the grain. The method is based on an existing testing method for unreinforced wood specimens. The Digital Image Correlation (DIC) method is used to monitor deformation during experiments. The experimental results of reinforced specimens are compared with those of paired unreinforced specimens tested in a previous study. The experimental method presented in this study shows that specific geometry and test considerations must be implemented when compared with the existing method for unreinforced specimens. © 2012 Elsevier Ltd. All rights reserved.

  • 46.
    André, Alann
    et al.
    RISE, Swerea, Swerea SICOMP AB.
    Nilsson, Sören
    RISE, Swerea, Swerea SICOMP AB.
    Asp, Leif
    RISE, Swerea, Swerea SICOMP AB.
    Finite element delamination study of a notched composite plate under flexural loads2009Ingår i: ICCM International Conferences on Composite MaterialsKonferensbidrag (Refereegranskat)
    Abstract [en]

    The delamination process in notched composite plates under flexural loading has been investigated using finite element analysis. Cohesive elements implemented in the commercial finite element package ABAQUS have been used in the region around the drilled-hole, and positioned between layers where delamination was observed during experiments presented in an accompanying paper. The delamination initiation and subsequent propagation was studied between the layers at the tension side separately and simultaneously. For all FE models, the load displacement curve was in good agreement with the one from experiments. However, the amount of damage reported from the fractography study was more extensive than that predicted by the models. Finally, it was shown that the models with only one cohesive layer show significantly different results to that of the model with four cohesive layers in terms of size of the degradation area.

  • 47.
    Angré, Alexander
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Ahlfors, Magnus
    QuintusTechnologies AB, Sweden.
    Chasoglou, Dimitri
    Höganäs AB, Sweden.
    Larsson, Linn
    AB Sandvik Technologies Material, Sweden.
    Claesson, Erik
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Karlsson, Oskar
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB AB.
    Phase transformation under isostatic pressure in HIP2017Ingår i: Powder Metallurgy, ISSN 0032-5899, E-ISSN 1743-2901, Vol. 60, nr 3, 167-174 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The new HIP cooling systems enable very fast cooling rates under isostatic pressure. This does not only enable shorter HIP cycles but also allows complete heat treatment cycles to be performed in one HIP cycle. It has been shown in previous studies that extreme pressures of several thousand bar can push phase transformation towards longer times. The new URQ HIP cooling systems give the opportunity to investigate the impact of pressures up to 2000 bar on phase transformation time dependency. For each of the two materials in this study, a comparison of austenite phase transformation time at 100 and 1700 bar was performed. The study was performed by isothermal heat treatment of specimens for a specific time followed by quenching. To evaluate the influence of pressure on hardenability, the phase fractions were evaluated using grid method on SEM images. The study found significant influence of HIP pressure on hardenability.

  • 48.
    Ankerfors, Caroline
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Wågberg, L.
    KTH Royal Institute of Technology.
    Polyelectrolyte complexes for tailoring of wood fibre surfaces2014Ingår i: Advances in Polymer Science, ISSN 0065-3195, E-ISSN 1436-5030, Vol. 256, s.1-24 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of polyelectrolyte complexes (PECs) provides new opportunities for surface engineering of solid particles in aqueous environments to functionalize the solids either for use in interactive products or to tailor their adhesive interactions in the dry and/or wet state. This chapter describes the use of PECs in paper-making applications where the PECs are used for tailoring the surfaces of wood-based fibres. Initially a detailed description of the adsorption process is given, in more general terms, and in this respect both in situ formed and pre-formed complexes are considered. When using in situ formed complexes, which were intentionally formed by the addition of oppositely charged polymers, it was established that the order of addition of the two polyelectrolytes was important, and by adding the polycation first a more extensive fibre flocculation was found. PECs can also form in situ by the interaction between polyelectrolytes added and polyelectrolytes already present in the fibre suspension originating from the wood material, e.g. lignosulphonates or hemicelluloses. In this respect the complexation can be detrimental for process efficiency and/or product quality depending on the charge balance between the components, and when using the PECs for fibre engineering it is not recommended to rely on in situ PEC formation. Instead the PECs should be pre-formed before addition to the fibres. The use of pre-formed PECs in the paper-making process is described as three sub-processes: PEC formation, adsorption onto surfaces, and the effect on the adhesion between surfaces. The addition of PECs, and adsorption to the fibres, prior to formation of the paper network structure has shown to result in a significant increase in joint strength between the fibres and to an increased strength of the paper made from the fibres. The increased joint strength between the fibres is due to both an increased molecular contact area between the fibres and an increased molecular adhesion. The increased paper strength is also a result of an increased number of fibre/fibre contacts/unit volume of the paper network. © Springer-Verlag Berlin Heidelberg 2013.

  • 49.
    Apruzzese, P.
    et al.
    Imperial College London.
    Falzon, B.G.
    Monash University.
    Olsson, R.
    RISE, Swerea, Swerea SICOMP AB.
    Modelling the postbuckling behaviour of impacted composite aerostructures2009Ingår i: ICCM International Conferences on Composite MaterialsKonferensbidrag (Refereegranskat)
    Abstract [en]

    Two approaches to modelling the effects of embedded defects and impact damage in composite aerostructures are presented. These differ in the manner n which the damage is represented; one as an equivalent delamination and the other as a soft inclusion with non-linear homogenized material properties. These techniques are applied to study the effects of defects and impact damage on the performance of composite panels.

  • 50.
    Arne, B.
    et al.
    RISE, Swerea, Swerea KIMAB AB.
    Björk, Thomas
    RISE, Swerea, Swerea KIMAB AB.
    Laser ablation breakdown spectroscopy technique for simultaneous analysis of steel and slags in metallurgical samples2009Ingår i: Yejin Fenxi/Metallurgical Analysis, ISSN 10007571, Vol. 29, nr 2, s.8-13 s.Artikel i tidskrift (Refereegranskat)
    Abstract [zh]

    The original purpose of this research was to develop a method for fast, simultaneous analysis of both the steel and slag content of heterogeneous metallurgical samples for process control. The method is based on Laser Induced Breakdown Spectroscopy (LIBS). The reason for choosing LIBS is that it can be employed for both conductive and non-conductive materials, and is relatively insensitive to sample shape and surface finish. The heterogeneous samples produced contain large numbers of sub-millimetre slag particles that cannot be completely separated from the surrounding steel in a LIBS analysis. A method has therefore been developed to perform a line scan analysis with approximately 0.5 mm resolution and 10 mm length along the sample. The laser pulse rate is 20 Hz and the scan speed is 1 mm/s. Slag particles appear in the line scan as "polluted areas" of the steel with very high concentrations of e. g. Ca, Al and Si. A mathematical model was developed to evaluate the data in steps, based on a single calibration. Firstly, "clean steel" areas are identified and the steel composition determined. In the second step, the average composition across the entire length of the scan is determined. In the final step, the average slag composition is determined by means of a difference calculation. The method was tested on several samples from the development of the heterogeneous sampler. It was found that the elements C, Si, Mn, P, S and Al can be determined in the steel with an RSD of a few percent. In the slag, the RSD's are higher, around10% for several important elements. It is expected that the method can be further developed for rapid analysis of smaller non-metallic inclusions.

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