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  • 151.
    Gamstedt, E. Kristofer
    et al.
    Uppsala University.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    de Borst, Karin
    University of Glasgow, UK.
    Mixed numerical–experimental methods in wood micromechanics2012In: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 47, no 1, p. 183-202Article in journal (Refereed)
    Abstract [en]

    Mixed numerical–experimental methods are increasingly used in various disciplines in materials science, recently also in wood micromechanics. Having a relatively irregular microstructure, direct interpretation of mechanical tests is not always possible since structurally specific properties are quantified rather than general material properties. The advent of combined numerical–experimental methods unlocks possibilities for a more accurate experimental characterization. A number of examples of mixed methods pertaining to both emerging experimental techniques and physical phenomena are presented: nano-indentation, moisture transport, digital-image correlation, dimensional instability and fracture of wood-based materials. Successful examples from other classes of materials are also presented, in an attempt to provide some ideas potentially useful in wood mechanics. Some general pit-falls in parameter estimation from experimental results are also outlined.

  • 152.
    Gamstedt, Kristofer
    et al.
    Uppsala University.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    de Borst, Karin
    University of Glasgow, UK.
    Mixed Numerical-Experimental Methods in Wood Micromechanics2012In: COST Action FP 0802: Experimental and computional micro-characterization techniques in wood mechanics, Edinburgh, UK, 2012, p. 86-87Conference paper (Other academic)
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    sammanfattning
  • 153.
    Gloimüller, Stefan
    et al.
    Vienna University of Technology, Austria.
    de Borst, Karin
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    Determination of the linear elastic stiffness and hygroexpansion of softwood by a multilayered unit cell using poromechanics2012In: Interaction and Multiscale Mechanics, An International Journal, ISSN 1976-0426, Vol. 5, no 3, p. 229-265Article in journal (Refereed)
    Abstract [en]

    Hygroexpansion of wood is a known and undesired characteristic in civil engineering. When wood is exposed to changing environmental humidity, it adsorbs or desorbs moisture and warps. The resulting distortions or - at restrained conditions - cracks are a major concern in timber engineering. We herein present a multiscale model for prediction of the macroscopic hygroexpansion behavior of individual pieces of softwood from their microstructure, demonstrated for spruce. By applying poromicromechanics, we establish a link between the swelling pressure, driving the hygroexpansion of wood at the nanoscale, and the resulting macroscopic dimensional changes. The model comprises six homogenization steps, which are performed by means of continuum micromechanics, the unit cell method and laminate theory, all formulated in a poromechanical framework. Model predictions for elastic properties of wood as functions of the moisture content closely approach corresponding experimental data. As for the hygroexpansion behavior, the swelling pressure has to be back-calculated from macroscopic hygroexpansion data. The good reproduction of the anisotropy of wood hygroexpansion, based on only a single scalar calibration parameter, underlines the suitability of the model. The multiscale model constitutes a valuable tool for studying the effect of microstructural features on the macroscopic behavior and for assessing the hygroexpansion behavior at smaller length scales, which are inaccessible to experiments. The model predictions deliver input parameters for the analysis of timber at the structural scale, therewith enabling to optimize the use of timber and to prevent moisture-induced damage or failure.

  • 154.
    Godinho, Pedro Miguel J.S.
    et al.
    Vienna University of Technology (TU Wien), Austria.
    Jajcinovic, Marina
    Graz University of Technology (TU Graz), Austria.
    Wagner, Leopold
    Vienna University of Technology (TU Wien), Austria.
    Vass, Viktoria
    Vienna University of Technology (TU Wien), Austria.
    Fischer, Wolfgang
    Graz University of Technology (TU Graz), Austria.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Hirn, Ulrich
    Graz University of Technology (TU Graz), Austria.
    Bauer, Wolfgang
    Graz University of Technology (TU Graz), Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology (TU Wien), Austria.
    Hellmich, Christian
    Vienna University of Technology (TU Wien), Austria.
    A continuum micromechanics approach to the elasticity and strength of planar fiber networks: Theory and application to paper sheets2019In: European journal of mechanics. A, Solids, ISSN 0997-7538, E-ISSN 1873-7285, Vol. 75, p. 516-531Article in journal (Refereed)
    Abstract [en]

    2D materials such as planar fibrous networks exhibit several mechanical peculiarities, which we here decipher through a 3D-to-2D transition in the framework of continuum micromechanics or random mean-field homogenization theory. Network-to-fiber concentration (or “downscaling”) tensors are derived from Eshelby-Laws matrix-inclusion problems, specified for infinitely long, infinitely flat fibers, and for infinitely flat spheroidal pores of vanishing stiffness. Overall material failure is associated with microscopic shear failure orthogonal to the fiber direction. Corresponding structure-property relations between porosity on the one hand, and in-plane stiffness as well as strength on the other hand, appear as linear. This is in good agreement with mechanical experiments carried out on pulp fibers, on pulp fiber-to-pulp fiber bonds, and on corresponding paper sheets.

  • 155.
    Godinho, Pedro M.J.S.
    et al.
    Vienna University of Technology, Austria.
    Jajcinovic, Marina
    Graz University of Technology, Austria.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Fischer, Wolfgang. J.
    Graz University of Technology, Austria.
    Bauer, Wolfgang
    Graz University of Technology, Austria.
    Hellmich, Christian
    Vienna University of Technology.
    A continuum micromechanics approach to the strength of planar fiber networks: paper material applications2017In: CompWood 2017 - Computational Methods in Wood Mechanics - From Material Properties to Timber Structures: Programme & Book  of Abstract / [ed] Josef Füssl, Thomas K. Bader, Josef Eberhardsteiner, Vienna: TU verlag , 2017Conference paper (Refereed)
  • 156. Godinho, Pedro M.S.J.
    et al.
    Jajcinovic, Marina
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Fischer, Wolfgang J.
    Hirn, Ulrich
    Bauer, Wolfgang
    Hellmich, Christian
    A continuum micromechanics approach to the strength of planar fiber networks: paper material applications2017In: Vienna Young Scientists Symposium, June 1-2, 2017, Vienna, Austria, 2017Conference paper (Refereed)
  • 157.
    Gren, Pierre
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Uppskärningsmaskin: Underlag till CE-märkning2008Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract (in English)

    The work that lead to a CE- marking and the creation of a total drawing foundation on an existing machine carried out on the company Polytec Composites Sweden AB in Ljungby. The company have design an machine that exist in six example that runs in the production. To be able to use the machine the company have to work out a CE-marking. The process that summed up all the document that needs for the machine to make a CE-marking. The documentation includes a total drawing over the machine and a risk analysis performed by a group employers on the company. The computer program that i used to make the drawings is Catia V5. The work that the company and the student performed ended up in a CE-marking of the machine.

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    FULLTEXT01
  • 158.
    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.
    Performance of multi-layered wood flooring elements produced with sliced and sawn lamellas2019In: Pro Ligno, ISSN 1841-4737, E-ISSN 2069-7430, Vol. 15, no 4, p. 166-172Article in journal (Refereed)
    Abstract [en]

    The performance of multi-layered wood flooring produced with sliced and sawn top-layers was evaluated in this study. Slicing checks side orientation was evaluated by pressing the veneers with checks side oriented upwards and/or downwards the flooring surface. The performance of  produced flooring boards were evaluated using a climate chamber test with regard to the dimensional stability (SS-EN:1910) and appearance. Delamination resistance was tested according to the ANSI delamination testing procedures. Results of the climate chamber test revealed immerging of a high amount of slicing checks to the surface of parquet boards after the first dry cycle. Checks tend to be larger around knots. Checking was qualitatively assessed as being more severe on the boards with checks side up. Dimensional stability was assessed to be slightly better for the sliced top-layers compared to the sawn ones. Parquet elements produced with  veneers checks side facing downwards had poor delamination resistance. The best results regarding delamination resistance was achieved when using sliced lamellas with the checks side facing up

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  • 159.
    Grund Bäck, Lina
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Karlsson, Stefan
    Glafo, the Glass Research Institute.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Physical properties and Raman Spectroscopy of mixed alkali/alkaline earth silicate glassesManuscript (preprint) (Other academic)
  • 160.
    Grund Bäck, Lina
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. RISE, Sweden.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Karlsson, Stefan
    RISE, Sweden.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. National Hellenic Research Foundation, Greece.
    Kamitsos, Efstratios
    National Hellenic Research Foundation, Greece.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mixed alkali/alkaline earth‐silicate glasses: Physical properties and structure by vibrational spectroscopy2019In: International Journal of Applied Glass Science, ISSN 2041-1286, Vol. 10, no 3, p. 349-362Article in journal (Refereed)
    Abstract [en]

    In this article, we investigate the correlation of selected physical properties with structural changes in quaternary mixed modifier alkali/alkaline earth oxide silicate glass systems, focusing either on the mixed alkali effect [(20−x)Na2O–xK2O–10CaO–70SiO2 (x = 0, 5, 10, 15, 20)] or on the mixed alkaline earth effect [20Na2O–(10−y)CaO–yBaO–70SiO2 (y = 0, 5, 10)]. A maximum microhardness and packing density, as well as a minimum glass transition temperature were observed for mixed alkali glasses. The mixed alkaline earth glasses do not exhibit any clear extrema in any of the properties studied. The hardness and glass transition temperature decreases, while the density and molar volume increases with increasing BaO content. Raman spectroscopy showed an increase in the Q3 group compared to the Q2 and Q4 groups as the high field strength ions Na+ or Ca2+ are substituted by their low field strength analogs K+ or Ba2+. In the mixed alkali series, the high field strength ion Na+, seems to push the low field strength ion K+ into lower energy sites when present simultaneously, while such an effect is not apparent for the mixed alkaline earth glasses, where the far IR spectra of mixed glasses are equivalent to the weighted averages of the pure glasses.

  • 161.
    Grund Bäck, Lina
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. RISE Research Institutes of Sweden, Sweden.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Karlsson, Stefan
    RISE Research Institutes of Sweden, Sweden;Friedrich Schiller University of Jena, Germany.
    Wondraczek, Lothar
    Friedrich Schiller University of Jena, Germany.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    X-ray and UV-Vis-NIR absorption spectroscopy studies of the Cu(I) and Cu(II) coordination environments in mixed alkali-lime-silicate glasses2019In: Journal of Non-Crystalline Solids: X, ISSN 2590-1591, article id 100029Article in journal (Refereed)
    Abstract [en]

    The local structures of Cu(I) and Cu(II) in (20-x)Na2O-xK2O-10CaO-70SiO2 glasses with a copper content of 0.4 mol% have been investigated by Cu K-edge extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES). Complementary data for Cu(II) was derived using UV–Vis-NIR spectroscopy. Indication for mainly linear two-fold coordination of the Cu+ ion was found by both EXAFS and XANES, but other coordination between Cu+ and O2– cannot be excluded. The Cu(I)O bond lengths were found to be 1.79–1.83 ± 0.02 Å. EXAFS results showed that Cu(II) was mostly present in a Jahn-Teller distorted environment with oxygen, an octahedron with four shorter Cu(II)O bonds and two longer in axial position. The equatorial bond lengths were found to be 1.89–1.91 ± 0.02 Å and the axial 2.20–2.24 ± 0.02 Å with no effect of the Jahn-Teller distortion of the octahedron when the glass composition was altered.

  • 162.
    Grund Bäck, Lina
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Jonson, Bo
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Lundstedt, Karin
    The influence of basicity on oxygen activity and antimony oxide fining efficiency in alkali alkaline earth aluminosilicate glasses2009In: European Journal of Glass Science and Technology. Part A: Glass Technology, ISSN 1753-3546, Vol. 50, no 5, p. 241-246Article in journal (Refereed)
    Abstract [en]

    The number of bubbles was monitored in antimony oxide fined R2O-MxOy-SiO2 and R2O-CaO-Al2O3-SiO2 glasses (R = Na, K; M = Ca, Mg, Ba, Sr, Zn, B, Al, Ti, x = 1 or 2, y = 1, 2 or 3) in order to evaluate the fining efficiency. Electrochemical measurements of oxygen activity were used to, in situ, monitor the fining characteristics and conditions in some of the investigated glass melts. The results showed that an increase of the calculated optical basicity was related to an increased number of bubbles in the glass samples. The oxygen activity in the melt during fining decreased with increased optical basicity.

  • 163.
    Gröndahl, Alexander
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Wernersson, Gustav
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Projektering av markarbete, parkeringsplatser, cykelställ m.m2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Arbetet tar upp lösningsförslag och val av lösning för en unik parkeringsplats på ett företag i Emmaboda. Lösningarna omfattar lokalt omhändertagande av dagvatten, val av beläggningstyper och trafiksäkerhet. Arbetet kommer att användas av Xylem till förfrågningsunderlaget för kommande anläggning av parkeringen.

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  • 164.
    Gustafsson, Åsa
    et al.
    Linnaeus University, School of Business and Economics, Department of Management Accounting and Logistics.
    Eliasson, Lars
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Product quality deficiencies in the prefabrication industry for single-family houses2014In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 9, no 1, p. 1-11Article in journal (Refereed)
    Abstract [en]

    In the industry for the prefabrication of single-family houses, previous research had indicated that individual companies have problems in securing the product quality of incoming softwood timber. This implies that they need to carry out a quality inspection and adjust the softwood timber when it arrives at their facility in order to fit their production. Opinions within the industry concerning product quality deficiencies differ with regard to the handling procedures and the percentage of perceived deficiencies. However, there are prefabricators of single-family houses that need to find additional areas for use for their purchased softwood timber, and spend several working hours on softwood timber to meet the quality criteria agreed upon. A previous study by Eliasson and Gustafsson puts forward a number of proposals regarding the quality deficiencies of softwood timber in this context. The present work transforms some of these proposals into hypotheses and aims at describing and understanding what affects the perception of product quality deficiencies. Questionnaires were used to collect data. The paper concludes that the purchase volume is indicated to be related to the volume portion of the deficiency in the product quality and that the level of information- and communication-technology support in production (i.e. the degree of automation) is indicated to be related to the inspection activity point. An extension of the proposed hypotheses concludes that the inspection activity point on arrival and/or on delivery into production also affects how companies do perceive product quality deficiencies. Research regarding what affects product quality deficiencies is lacking in recognizing and knowing what is aligned with the perception of product quality deficiencies; the individual companies will have an opportunity to affect and manage their appearance and thereby enhance the use of softwood timber.

  • 165.
    Hakeem, Abbas Saeed
    et al.
    King Fahd University of Petroleum & Minerals (KFUPM).
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Preparation and properties of mixed La–Pr silicate oxynitride glasses2013In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 368, p. 93-97Article in journal (Refereed)
    Abstract [en]

    The preparation and properties of mixed lanthanide (La, Pr) silicate oxynitride glasses are reported. These oxynitride glasses were prepared by melting mixtures of La, Pr, SiO2 and Si3N4 powders in a nitrogen atmosphere at 1750 °C. The glasses were characterized by X-ray powder diffraction, differential thermal analysis, scanning and transmission electron microscopy. Glass compositions were calculated from the analyses obtained by energy dispersive X-ray (EDX) spectroscopy and combustion analysis, for cation and anion compositions, respectively. The glasses were found to be homogenous, optically opaque black, and to contain contents up to 66 e/o of N and up to 48 e/o of La–Pr. The physical properties were found to vary linearly with the degree of substitution of La by the Pr. Determined glass density increases substantially upon the substitution of La by Pr, up to 5.49 g/cm3. The calculated molar volumes and compactness values decrease and increase respectively by the substitution of Pr for La. Glass transition temperatures and microhardness increase upon the substitution by Pr, up to 1086 °C and 10.98 GPa, respectively. The refractive index increases upon the substitution by Pr up to 2.00.

  • 166.
    Hellmich, Christian
    et al.
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Hofstetter, Karin
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    Role of Water in Cell Walls of the Hierarchical Composite "Softwood": A Poroelastic Analysis2011In: Engineering Mechanics Institute 2011 Conference (EMI 2011), Bonston, 2011, p. 195-Conference paper (Other academic)
  • 167.
    Henriksson, Erika
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Carbon footprint: analys av slipmaterial2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Oy KWH Mirka Ab tillverkar slipmaterial genom energikrävande termiska härdningsprocesser där processångan produceras genom förbränning av tjockolja. P.g.a. miljökrav från myndigheter och samhälle vill Mirka beräkna miljöbelastningen från sin nuvarande produktion. En del av produktionen har redan konverterats till ny teknik med EB/UV härdning. Utöver detta planeras en förbränningsanläggning för produktionsspill och flis för ångproduktion, samt återvinning av slipkorn från askan. I studien beräknas carbon footprint för tre produkter som produceras konventionellt med processånga. Växthusgasemissionerna delas upp i bidrag från råmaterial, produktionen, transporter och konfektioneringen. Dessutom jämförs hur omställningen till bioenergi, slipkornsåtervinningen och EB/UV-tekniken påverkar växthusgasutsläppen.

    Enligt resultatet är carbon footprint för Gold P120 4,37 kg CO2 eq/100 st 150 mm rondeller. Gold P240 och P500 har 3,25 respektive 3,28 kg CO2 eq/100 st rondeller. Bidraget från råmaterialproduktionen är 68-73 %.

    Vid förbränning av produktionsspill och återvinning av slipkorn minskar emissionerna med 22-25 %. Växthusgasutsläppen i EB/UV processer är bara 16 % av de konventionella processernas utsläpp.

  • 168.
    Henriksson, Felix
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Strebel, Conrad
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Legeringsintervallets påverkan på dem mekaniska egenskaperna på aluminiumlegeringen EN AB-460002015Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Undersökningens syfte är att kvantifiera legeringsintervallets påverkan på hållfastheten hos två olika aluminiumlegeringar som tillverkas av återvunnet aluminium, EN AB-46000 och en modifierad variant av denna, Modifierad 46000. Examensarbetet har utförts i samarbete med Stena Aluminium (SA) i Älmhult som återvinner aluminium från skrot. Detta har genomförts genom gjutning av provstavar, mekanisk provning samt mikroskopering. Gjutningen gjordes på Tekniska Högskolan i Jönköping (JTH), dragprovningen på Linnéuniversitet (LNU) och mikroskoperingen både på LNU och SA. All data som samlades in analyserades sedan för att kunna sammankoppla legeringssammansättning med hållfasthetsvärden och mikrostruktur.

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  • 169.
    Henrysson, Konrad
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Energikartläggning av ånga, processventilationssystemet och el på pappersmaskin 2, Stora Enso paper Nymölla AB: Energikartläggning utifrån lagen (2014:266) och ISO 50001:2011 på pappersmaskin 2.2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In order to improve the company's energy efficiency, a international law in 2014 was introduced to carry out energy surveys on companies with more than 250 employees, with annual income of more than 50 million euros, or over 43 million in total assets. Nymölla Bruk are included in this law and must therefore carry out energy mapping every four years and report it to the Swedish energy department. This law is the purpose for this degree project based to carrying out an energy survey on paper machine 2 in Nymölla Bruk.

    In the desiccator, 8.89 kg/s of water is evacuated from the paper with a gram weight of 120g/m2 and 10.45 kg/s with a gram weight of 80g/m2. The likely reason that it can evaporate more water from the paper in the lower grammage is that the paper is driven through the machine at a higher rate. The paper machine can produce 120g/m2 paper at a speed of 9.67 m/s and 80g/m2 paper at a speed of 12.22 m/s. The evaporating difference between gram weights can also be seen in the aftermath. The mass flow for point 20 which is at the exhaust air fan as shown in Figure 9 on page 25 of the report could not be reported due to the absence of a meter in place, and calculations for producing the mass flow did not work when the fan diagram from the fan manufacturers probably did not match the fan on which the measurements were made.

    In order to make an complete energy examination on this machine in regard of steam, condensate and process ventilation, it is necessary that the mass flow for point 20 can be known. The balance of the leakage into the dryer can not be determined without mass flow variable, making the energy consumption required to heat the air with steam impossible to calculate. Therefore, a further study should be done to carry out for making an complete energy examination.

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  • 170.
    Hofstetter, Karin
    et al.
    Vienna University of Technology, Austria.
    Eitelberger, Johannes
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Hellmich, Christian
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    Computational Multiscale Approach to the Mechanical Behavior and Transport Behavior of Wood2009In: Computational Structural Engineering: Proceedings of the International Symposium on Computational Structural Engineering, held in Shanghai, China, June 22–24, 2009, Springer, 2009, p. 79-85Conference paper (Other academic)
    Abstract [en]

    Moisture considerably affects the macroscopic material behavior of wood. Since moisture takes effect on wood at various length scales, a computational multiscale approach is presented in this paper in order to explain and mathematically describe the macroscopic mechanical and transport behavior of wood. Such an approach allows for appropriate consideration of the underlying physical phenomena and for the suitable representation of the influence of microstructural characteristics of individual wood tissues on the macroscopic behavior. Continuum (poro-)micromechanics is applied as homogenization technique in order to link properties at different length scales. Building the model on universal constituents with tissue-independent properties and on universal building patterns, the only tissue-dependent input parameters are wood species, mass density, moisture content, and temperature. All these parameters are easily accessible, what renders the models powerful and easily applicable tools for practical timber engineering.

  • 171.
    Hofstetter, Karin
    et al.
    Vienna University of Technology, Austria.
    Hellmich, Christian
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    Poro-micromechanical Estimates for Elastic Limit States of Wood2008In: Eleventh East Asia-Pacific Conference on Structural Engineering and Construction, Taipei, Taiwan, 2008, p. 550-551Conference paper (Other academic)
  • 172. Hofstetter, Karin
    et al.
    Hellmich, Christian
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Relevance of Microstructural Failure Mechanismus for Macroscopic Elastic Limit States of Wood2008Conference paper (Other academic)
  • 173.
    Holmgren, Magnus
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Rening av väte vid återvinning av aluminium: Purification of hydrogen in aluminum recycling2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete har utförts på Stena Aluminium (SA) i Älmhult. Undersökningen handlar om att mäta vätgashalten genom densitetsindexprover på smält aluminium, för att kartlägga hur vätgashalten påverkas av processtegen vid återvinning av aluminium i SAs produktions-anläggning. I arbetet ingick att undersöka vätgashalten för två olika legeringstyper (EN-AB 43400 och 46000), utvärdera avgasningseffektivitet för de utvalda legeringstyperna och att utvärdera den befintliga utgjutningssystemet. Mätningar för undersökningen är utförda i SAs smältverk, vid processtegen raffinering och utgjutning.

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    Rening av väte vid återvinning av aluminium
  • 174.
    Holmgren, Magnus
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Dugic, Izudin
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Liljenfors, Tomas
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Purification of hydrogen in aluminium recycling2014In: Proceeding book of the 14th international foundrymen conference / [ed] Unkić, Faruk, Sisak, Croatia: University of Zagreb Faculty of Metallurgy , 2014, , p. 9p. 17:1-17:8Conference paper (Other academic)
    Abstract [en]

    Second to steel, aluminium is the most widely used metal and its applications are manifold. It is available in all forms; such is wire, bars, extrusions, power, forging and casting. One of the major characteristics of aluminium is that it is very well suited for recycling. Recycled aluminium is known as secondary aluminium, but maintains the same physical properties as primary aluminium.

     The Company XY is a cast house in the Nordic countries supplying aluminium cast products. Customers today are placing greater demands on the products strength and quality. An important quality parameter of aluminium is its purity from contaminants, where hydrogen is one of the major issues with impact on the strength of the final product.

     The hydrogen content has been measured by Density Index for two different types of alloys (EN AB-43400 and EN AB-46000), at specific locations, at different stages in the process and with different degassing methods. Density Index is a measure for measuring and comparing the samples with respect to the internal porosity. As the air contains moisture, along with the melt temperature, the solubility of hydrogen in the melt is affected.

     The project work has focused on reducing the hydrogen content and to improve the strength of the final product. 

  • 175.
    Hosseinpourpia, Reza
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology. Linnaeus University.
    Adamopoulos, Stergios
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Eceiza, Arantxa
    University of the Basque Country UPV/EHU, Spain.
    Thermal stability and water vapor sorption of wheat starch modified with isocyanate functional groups2019In: 7th International Conference on Biobased and Biodegradable Polymers (BIOPOL), 17-19th June 2019, Stockholm, Sweden, KTH , 2019Conference paper (Refereed)
    Abstract [en]

    Wheat starch polymer was modified through the unequal reactivity of isocyanate groups in isophorone diisocyanate (IPDI) monomer. Fourier transform infrared spectroscopy (FTIR) and 13C nuclear magnetic resonance (13C NMR) confirmed the presence of both urethane and isocyanate functionalities in the modified polymer. Thermal stability and water vapor sorption properties of the modified polymer were evaluated by means of thermogravimetric analysis (TGA) and auto-dynamic vapor sorption (AVS) method, respectively. The results indicated that the modified starch polymer showed a better thermal stability (e.g. higher temperature at maximum weight loss) compared to the unmodified one. Water vapor sorption of starch polymer was considerably reduced after modification with IPDI monomer.

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  • 176.
    Hosseinpourpia, Reza
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Adamopoulos, Stergios
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Mai, Carsten
    Georg-August-University Göttingen, Germany.
    Taghiyari, Hamid Reza
    Shahid Rajaee Teacher Training University, Iran.
    Properties of medium-density fibreboards bonded with dextrin-based wood adhesive2019In: Wood research, ISSN 1336-4561, Vol. 64, no 2, p. 185-194Article in journal (Refereed)
    Abstract [en]

    This study focuses on manufacturing of medium density fibreboard (MDF) panels bonded with dextrin-based wood adhesive and crosslinked in situ with various weight ratios of synthetic (e.g., polymeric-methane diphenyl-diisocyanate, pMDI) or bio-based (e.g., glyoxal) crosslinkers. The physical and mechanical properties of the panels were evaluated and compared with those from panels without crosslinker (control). Modulus of rupture (MOR) and internal bond (IB) strength of the MDF panels were considerably increased by increasing the crosslinkers’ content. While, slight improvements were observed in modulus of elasticity (MOE) of the panels as a function of crosslinker type and content. Addition of crosslinkers clearly reduced the thickness swelling (TS) and water absorption (WA) of the panels, whereas, the panels with pMDI showed superior performances than the control and glyoxal added ones within 4 h and 24 h immersion in water. The results indicate the potential of dextrin as wood panel adhesive along with the use of appropriate crosslinkers.

  • 177.
    Hosseinpourpia, Reza
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Adamopoulos, Stergios
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Parsland, Charlotte
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Utilization of different tall oils for improving the water resistance of cellulosic fibers2019In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 136, no 13, article id 47303Article in journal (Refereed)
    Abstract [en]

    This study was conducted to assess the effect of the pulping by-products crude tall oil (CTO), distilled tall oil (DTO), andtall oil fatty acid (TOFA) on dynamic water vapor sorption behavior, interfiber strength, and thermal stability of cellulosic paper-sheets.The results were compared against those obtained in cellulose papers treated with the conventional petroleum-derived hydrophobicagent hydrowax and in untreated ones. The tall oil treatments caused strong reduction in equilibrium moisture content of the paper-sheets during adsorption and desorption runs. The same trend was noticed for the hydrowax-treated papers, however, it was lesspronounced than the CTO-treated and DTO-treated samples in the relative humidity range of 75–95%. The sorption hysteresis was con-siderably decreased after the treatments. The ultimate dry-tensile strengths of the paper-sheets were significantly reduced by TOFA andhydrowax treatments, while CTO and DTO showed comparable strength as that of untreated control. The ultimate wet-strengths of thepaper-sheets were improved after the treatments. The thermal stability of the specimens was improved by the tall oil treatments, and thehydrowax-treated samples illustrated lower degradation temperature than the untreated control. The results are promising for the use oftall oils as alternative hydrophobic agents of cellulosicfiber-based products, such as wood panels and paper packaging.

  • 178.
    Huang, Tianxiao
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Hydrophobic Coating on Cellulosic Textile Material by Betulin and a Betulin Based Polymer2016Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Betulin is a naturally abundant compound in the outer bark of birch and can be easily

    obtained by solvent extraction. Herein, solutions of betulin were used to treat cellulosic

    textile fibers and improve their water repellency. Cotton fabrics impregnated in a 7.5 g

    L-1 solution of betulin in ethanol showed the highest water contact angle of about 153°

    while the impregnation in a 3.75 g L-1 solution resulted in a close effect. A terephthaloyl

    chloride-betulin copolymer was synthesized and dissolved in tetrahydrofuran to afford a

    solution with a concentration of 3.75 g L-1. The cotton fabric impregnated in this

    solution showed a water contact angle of 150°. Changes in morphology of the cellulose

    fibers before and after the treatment were observed by scanning electron microscopy,

    and the water repellency was measured by a standard spray test. The marketing strategy

    of the potential product, which will be developed based on this technique, was discussed.

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  • 179.
    Hultberg, Ann-Charlotte
    et al.
    Växjö University. Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Larsson, Emelie
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Tilläggsisolering inom byggnadsvård2009Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This report evaluates if there are any known facts that support that the hygroscopic and ecologic materials are better in supplement insulation than non hygroscopic. Different kind of insulate materials from these two mentioned groups are compared from without different kind of parameters.

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  • 180.
    Håbecker, Linus
    et al.
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Strömberg, Victor
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Superhydrofobisk Coating: En studie som försöker minska rörfriktionsförluster med hjälp av invändig ytbehandling.2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The greatest loss of energy in a pipe system has many times been proven to be frictional loss. This study with that in mind, will try to answer if this type of loss can be prevented using a superhydrophobic coating on the inside of a pipe.

     

    This study uses two small-scale systems, one circulation system and one simplified system for freeflow testing. On both systems, measuring equipment is fixated close to the 1,5m test-pipe. Therefore, calculated and measured data is not distorted by the surrounding components. Measuring equipment is used to check volumetric flow, velocity, temperatures and differential-pressure. This data is later used to compare the frictional losses before and after applying the superhydrophobic coating.

     

    The results, after completed tests are the opposite of the expected results. The coating that has been used for this study causes a negative effect and, in turn results in a substantial increase of frictional loss.

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  • 181.
    Irshad, Hafiz Musammil
    et al.
    King Fahd University of Petroleum & Minerals, Saudi Arabia.
    Hakeem, Abbas Saeed
    King Fahd University of Petroleum & Minerals, Saudi Arabia.
    Ahmed, Bilal Anjum
    King Fahd University of Petroleum & Minerals, Saudi Arabia.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Ali, Sadaqat
    Imam Abdulrahman bin Faisal University, Saudi Arabia.
    Ali, Sameer
    University of Gujrat, Pakistan.
    Ehsan, Muhammad Ali
    King Fahd University of Petroleum & Minerals, Saudi Arabia.
    Laoui, Tahar
    King Fahd University of Petroleum & Minerals, Saudi Arabia.
    Effect of Ni content and Al2O3 particle size on the thermal and mechanical properties of Al2O3/Ni composites prepared by spark plasma sintering2018In: International journal of refractory metals & hard materials, ISSN 0958-0611, E-ISSN 2213-3917, Vol. 76, p. 25-32Article in journal (Refereed)
    Abstract [en]

    Alumina-nickel composites were prepared by carrying out spark plasma sintering (SPS) of nano-sized and micro-sized Al2O3particles with 15–45 wt% Ni powders. The powder materials were sintered at a temperature of1400 °C under a constant uniaxial pressure of 50 MPa. FESEM micrographs of the products showed uniformlydispersed nickel inclusions in both matrices at intergranular positions. Presence of Al2O3as the major phasealong with Ni as the minor phase was confirmed using XRD analysis. Thermal and mechanical properties of thenano- and micro-sized Al2O3/Ni composites were investigated. The thermal conductivity of nano-sized aluminacomposites was seen to increase with the increase in nickel content, however, an opposite trend was observed formicro-sized alumina-based composites. Moreover, thermal conductivities of all the composites decreased withincrease in temperature. The composites also showed high hardness and fracture toughness values of up to19.6 GPa and 4.71 MPa ∗ m1/2, respectively, and relative density values, between 79 and 99%, that decreasedwith increasing Ni content. Furthermore, the nano-sized Al2O3/Ni composites showed thermal and mechanicalproperties superior to those of the micro-sized Al2O3/Ni composite.

  • 182.
    Ivarsson, Tom
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Nytt material i kontaktröret vid MAG-svetsning2016Independent thesis Basic level (professional degree), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Svetsning är idag den mest använda sammanfogningsmetoden för metaller, och pågrund av metodens relativt enkla utförande och höga produktivitet är MIG/MAG-svetsning idag den mest använda svetsmetoden industriellt i hela världen. En viktig del av svetsutrustningen till MIG/MAG är svetspistolen. Strömöverföringen från pistol till tillsatsmaterial sker genom en komponent som kallas kontaktrör. Kontaktröret är traditionellt tillverkat av koppar.

    Målet med detta examensarbete är att fastställa huruvida det nya materialet i ett kontaktrör påverkar grundmaterialet och svetsgodset negativt vid svetsning.

    Slutsatsen som drogs var att det nya materialet i kontaktröret inte har en negativ påverkan på grundmaterialet eller svetsgodset vid svetsning. Produkten kaneventuellt leda till stora ekonomiska och ekologiska vinster för svetsindustrin i framtiden.

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  • 183.
    Jiang, Wen
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Kumar, Anuj
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology. Natural Resources Institute Finland (Luke), Finland.
    Adamopoulos, Stergios
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Liquefaction of lignocellulosic materials and its applications in wood adhesives — A review2018In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 124, p. 325-342Article in journal (Refereed)
    Abstract [en]

    Liquefaction, a useful method of turning whole biomass into liquids, provides advantages for energy andpolymers and finds applications in many sectors. This paper reviews the different liquefaction technologies andrecent advances in the development of sustainable wood adhesives. Current liquefaction technologies includehydrothermal liquefaction (HTL) and moderate acid-catalyzed liquefaction (MACL). HTL produces bio-oils asprimary products, and solid residues and gases as by-products. MACL depends on the solvent types used, whichare grouped to polyhydric alcohols and phenols. Bio-polyols from alcohol liquefaction, phenolated biomass fromphenol liquefaction and phenolic compounds rich-HTL bio-oils have been used in the production of liquefiedbiomass-based adhesives, which have shown competitive properties but face challenges for industrial uses. Yet, abetter understanding of reaction pathways and optimization of the liquefaction processes is needed.

  • 184.
    Jin, Min
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Determination of fracture mechanics behavior of polyethylene sheets2017Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Polyethylene is a widely-used material in package industries. The fracture behavior of this material has not been studied in the plastic region in many years. In this thesis work, the J-Integral which is one material property used to represent the plastic material strength is calculated through the numerical analysis. To build a correct numerical model, the material behavior is summarized from previous uniaxial tensile test. The result from the fracture experiment for variable initial crack length is used to validate the reliability of the numerical model. The numerical analysis is done by the software ABAQUS which has the function to get the value of J-Integral directly. The final result contains the comparison between experiments and numerical analysis and the value of J-Integral at the crack initiation. 

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  • 185.
    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.

  • 186.
    Johansson, Theo
    et al.
    University of Kalmar, Kalmar Maritime Academy.
    Seidow, Gustav
    University of Kalmar, Kalmar Maritime Academy.
    samband mellan olyckor i den svenska handelsflottan2008Independent thesis Basic level (professional degree), 5 poäng / 7,5 hpStudent thesis
    Abstract [en]

    Collisions between vessels and allisions between vessel and obstacles as well as groundings constitute a great problem within the shipping business. Serious damage to vessels, environmental disasters and great costs are invoked for everyone involved. Is it possible that deficient bridge procedures are the reasons behind these types of accidents? The purpose of this thesis is to gather material from accident reports from the years 2000-2007, to investigate whether there are any connections between the accidents on Swedish merchant vessels which have been involved in collisions with each other, allided with an obstacle or that have grounded. The results showed, among other things, that motor tankers are involved in groundings more often than other types of vessels. On the basis of these results, interviews were carried out with motor tanker officers and pilots to investigate what the situation is like onboard during the circumstances where these vessels are most usually grounded. Several of the informants state that paperwork and checklists have become a burden to them during their bridge watches, and one of the implications of our investigation is that inadequate supervision could be the reason behind the accidents.

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  • 187.
    Johansson, Wilhelm
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Peralta, Albert
    KTH Royal instute of technology, Sweden.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Anand, Srinivasan
    KTH Royal instute of technology, Sweden.
    Österlund, Lars
    Uppsala University, Sweden.
    Karlsson, Stefan
    RISE, Sweden.
    Transparent TiO2 and ZnO Thin Films on Glass for UV Protection of PV Modules2019In: Frontiers in Materials, E-ISSN 2296-8016, Vol. 6, article id 259Article in journal (Refereed)
    Abstract [en]

    Failure of PV modules frequently occurs as a result of degradation of their encapsulation material by destructive UV radiation. Both the life expectancy and efficiency of PV modules can be improved by reducing the transmittance of the destructive UV radiation through the cover glass without compromising the transmittance in the visible wavelength region. In addition, if the absorbed UV photons can be down-shifted to wavelengths that can be more efficiently converted to electrical energy, an additional increase of the PV efficiency could be achieved. In this study we have investigated transparent ZnO and TiO2 thin films deposited by spray pyrolysis on soda lime silicate float glass as functional layers on PV cover glass. The optical bandgap, UV-cutoff, UV-Vis transmittance, reflectivity (total and diffuse) and photoluminescence have been determined. The ZnO coating shifted the optical bandgap to longer wavelengths, resulting in a reduction of the transmittance of destructive UV radiation by up to similar to 85%. Distinct photoluminescence peaks at 377 nm and at 640 nm were observed for one of the ZnO samples. The TiO2 coated glasses also showed an increased UV cutoff, which resulted in a reduction of transmittance of destructive UV radiation by up to 75%. However, no photoluminescence peaks could be observed from the TiO2 films with 325 nm excitation laser, which can be explained by the fact that only indirect interband transitions are accessible at this excitation wavelength. Deposition of both ZnO and TiO2 coatings resulted in a reduction of the transmitted light convertible by PV modules, by up to 12.3 and 21.8%, respectively. The implication of the results is discussed in terms of lifetime expectancy and efficiency of PV modules.

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  • 188.
    Johansson, Wilhelm
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Peralta, Albert
    KTH Royal instute of technology, Sweden.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Anand, Srinivasan
    KTH Royal instute of technology, Sweden.
    Österlund, Lars
    Uppsala University, Sweden.
    Karlsson, Stefan
    RISE, Sweden.
    Transparent TiO2 and ZnO Thin Films on Glass for UV Protection of PV Modules2020In: American Ceramic Society Bulletin, ISSN 0002-7812, Vol. 9, no 4, p. 26-29, article id 259Article in journal (Other academic)
    Abstract [en]

    To stabilize the global temperature and mitigate climate change, the emission of anthropogenic greenhouse gases will have to be greatly reduced. To make it possible, the energy sector will have to transfer from fossil energy to environmentally friendly and carbon neutral sources.

  • 189.
    Jonson, Bo
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Lundstedt, Karin
    Stålhandske, Chrsitina
    A CIELAB approach facilitating glass decolourising and recycling of coloured cullet2009In: European Journal of Glass Science and Technology. Part A: Glass Technology, ISSN 1753-3546, Vol. 50, no 2, p. 89-94Article in journal (Refereed)
    Abstract [en]

    The CIELAB coordinate has demonstrated as useful for description of the colour characteristics of decolourised flint glass. The amounts of cobalt and erbium oxides necessary for sufficient decolourising of additions of coloured cullet can be calculated from the appearant linear dependence of CIE a* and b* coordinates to the added amounts of cobalt and erbium oxides to the batch. For the sucess of such a calculation, the colour point of the added cullet must be determined.

  • 190.
    Jonson, Bo
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Stålhandske, Christina
    Glafo, SE-35196 Vaxjo, Sweden.
    Devitrification and dilatometric properties of low T-g unleaded silicate glasses2013In: European Journal of Glass Science and Technology. Part A: Glass Technology, ISSN 1753-3546, Vol. 54, no 3, p. 108-110Article in journal (Refereed)
    Abstract [en]

    Candidate lead free glass enamels have been sought within the glass system described in general terms by the mole fractions 0.25R(2)O center dot 0.16(R'O,R-2 '' O-3)center dot 0.59SiO(2) where R=Li, Na, K; R'=Ba, Zn and R ''=B, Bi. Glass compositions containing high mole fractions of Li2O were found to devitrify when they were heated to temperatures up to 530 degrees C typical for the procedure used when fusing enamels to tableware glasses. The devitrification characteristics are complex and several peaks attributed to crystallisation were found by DSC characterisation. The thermal expansion coefficient (alpha) within the system ranges from 11-14x10(-6) K-1 and the glass transition temperatures (T-g) between 410-460 degrees C. The measured data could be fitted to the chemical composition by multiple regression analysis with a general equation of the form: (alpha,T-g)=K((alpha/Tg))+Sigma(cRxfR) in which K is a constant, c is the oxide mole fraction and f is an oxide specific factor. The statistical analysis correlation coefficients (r(2)) were around 0.9.

  • 191.
    Josefsson, Simon
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Berndt, Robin
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Icke-metalliska defekters inverkan på utmattningshållfasthet för sätthärdade kolstål i kugghjul2017Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Inom fordonsindustrin arbetas det kontinuerligt med att utveckla mer miljövänliga och ekonomiska produkter. Genom att undersöka material och förbättra utmattningshållfastigheten på befintliga material kan växellådor bli mer kompakta, ekonomiska och starkare samtliga parter. Syftet och målet med detta arbete är att få en generell förståelse för icke-metalliska inneslutningar och hur de påverkar ett materials utmattningshållfasthet, samt att ge förslag på förbättringar till den nuvarande materialspecifikationen. Genom tester på ultraljud kan en klar skillnad mellan storleken på defekter ses mellan stål tillverkade med olika processer. Genom undersökande av tidigare utförda tester på roterande böj kan en ökning av utmattningshållfastigheten på 37.5% ses mellan ett götgjutet stål och ett stränggjutet. Vid studerande av internationella och Europeiska standarder kan korrigeringar till den nuvarande materialspecifikationen föreslås.

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  • 192. Jäger, Andreas
    et al.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Hofstetter, Karin
    Eberhardsteiner, Josef
    Identification of Elastic Properties of Wood Cell Walls by Means of Nanoindentation2009In: 26th Danubia-Adria Symposium on Advances in Experimental Mechanics, Leoben, Austria, 2009, p. 83-84Conference paper (Other academic)
  • 193.
    Jäger, Andreas
    et al.
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Hofstetter, Karin
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    The relation between indentation modulus, microfibril angle, and elastic properties of wood cell walls2011In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 42, no 6, p. 677-685Article in journal (Refereed)
    Abstract [en]

    Nanoindentation is a well known tool for identification of mechanical properties at the micrometer scale of materials. When applied to study wood cell walls the commonly used isotropic indentation theory is not applicable. In this study, anisotropic nanoindentation theory was employed for analyzing nanoindentation test results on wood cell walls. The influence of elastic stiffness components, microfibril angle, and cell wall composition on the indentation modulus was studied. The indentation modulus was found to depend on longitudinal, transverse, and shear modulus to a similar extent. A significant influence of the microfibril angle on the indentation modulus was observed and discussed with respect to experimental scatter and sample preparation. It is concluded, that application of anisotropic nanoindentation theory provides a tool for quantitative instead of qualitative investigation of wood cell walls, with the goal of identifying all elastic properties of the transversely isotropic cell wall from nanoindentation tests.

  • 194.
    Karlsson, Stefan
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Determination of diffusion characteristics of ion exchanged float glass by use of a Surface Ablation Cell (SAC)2009Conference paper (Other academic)
  • 195.
    Karlsson, Stefan
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Glass strengthening and ion exchange phenomena2010Conference paper (Other academic)
  • 196.
    Karlsson, Stefan
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Ion exchange of monovalent ions in float glass2010Conference paper (Other academic)
  • 197.
    Karlsson, Stefan
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Ion exchange processes on float glass surfaces2010Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Glass can be strengthened by ion exchange and this process is presently used inspecial applications e.g. aircraft windshields, displays and spectacle lenses allowinga higher production cost. Chemically strengthened float glass is moreexpensive than thermally strengthenened, but will likely find applications in futurebuilding and interior constructions where strength demands, design andshape prevent the use of thermal strengthening. The aim of this work is tostudy ion exchange on float glass surfaces. In longer terms, the chemicalstrengthening is planned to be applied to specific critical area e.g. around adrilled hole which without treatment deteriorates the overall strength of theglass.Strengthening the glass through ion exchange can be done in several ways butis most often referred to as the replacement of smaller ions in the glass structureby larger ions from the salt used for treatment. By determining concentrationvs. depth profiles of ion exchanged float glasses, it is possible to calculate thediffusion coefficients and activation energy for different ions. In this study, theless frequently studied approach single-side ion exchange of different ions ofcommercial float glass is described. The concentration vs. depth profiles weredetermined either by the use of the Surface Ablation Cell (SAC), which allowsthe continuous removal of the material from a flat glass surface by slow controlledisotropic dissolution or SEM-EDX.The results of the work are that similar diffusivities and concentration vs. depthprofiles are achieved with single-side ion exchange as from the traditional wayof immersing glass in molten salt bath. Ion exchange of Ag+ stains the floatglass on both sides giving it a yellow or amber-brownish colour. Unlike Ag+ ionexchange of Cu+ stains the float glass on the tin-side only, giving it a yellow,red or red-brown colour. Determining the concentration vs. depth profiles ofion exchanged float glasses with the SAC was convenient except for Ag+ whichwas determined with SEM-EDX. The work confirms that the procedure andequipment of the SAC are very cheap, easy to use and gives data similar tothose gained by much more expensive equipment. Calculated diffusion coefficientsof K+, Ag+ and Rb+ are in accordance with literature data while Cu+ and Cs+ diffusion coefficients were slightly lower. The diffusion coefficients of the different ions follow the order Ag+>K+>Cu+>Rb+>Cs+ and ranges between9.4E-10 and 4.8E-13 cm2s-1. The calculated activation energies for diffusion of K+, Ag+ and Cu+ corresponds with reported literature data and were calculated to: Ag+(air-side) 152 kJ/mol, Ag+(tin-side) 185 kJ/mol, K+ 108 kJ/mol and Cu+115 kJ/mol.

  • 198.
    Karlsson, Stefan
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Modification of Float Glass Surfaces by Ion Exchange2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Glass is a common material in each person’s life, e.g. drinking vessels, windows, displays, insulation and optical fibres. By modifying the glass surface it is possible to change the performance of the entire glass object, generally known as Surface Engineering. Ion exchange is a convenient technique to modify the glass surface composition and its properties, e.g. optical, mechanical, electrical and chemical properties, without ruining the surface finish of the glass.

     

    This thesis reports the findings of two different research tasks; characterisation of the single-side ion exchange process and the novel properties induced. The characterisation of the ion exchange process was mainly performed by utilising a novel analytical equipment: the Surface Ablation Cell (SAC), allowing continuous removal of the flat glass surface by controlled isotropic dissolution. SAC-AAS has provided concentration vs. depth profiles of float glass ion exchanged with K+, Cu+, Rb+ and Cs+. In addition, SEM-EDX has provided concentration vs. depth profiles of Ag+ ion exchanged samples and validation of a copper concentration vs. depth profile. From the concentration vs. depth profiles, the effective diffusion coefficients and activation energies of the ion exchange processes have been calculated. Depending on the treatment time and treatment temperature, penetration depths in the range of 5-10 μm (Rb+, Cs+), 20-30 μm (K+, Cu+) and 80-100 μm (Ag+) can be readily obtained. The effective diffusion coefficients followed the order Ag+>K+>Cu+>Rb+>Cs+. This is in accordance with the ionic radii for the alkali ions (K+<Rb+<Cs+) but reverse for the noble metal ions (Cu+<Ag+).

     

    The glass properties modified by single-side ion exchange have mainly been characterised by UV-VIS spectroscopy and flexural strength measurements. Cu+ and Ag+ ion exchange give rise to surface colouration, Cu+ copper-ruby and Ag+ yellow/amber. The surface-ruby colouration was found to depend on the residual tin ions in the tin-side of the float glass. The flexural strength was studied using the coaxial double ring-test method which also was suitable for holed specimens. The flexural strength of K+ ion exchanged float glass samples was found to substantially increase compared to untreated.

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    S Karlsson - Modification of Float Glass Surfaces by Ion Exchange
  • 199.
    Karlsson, Stefan
    et al.
    Glafo, Sweden;University of Jena, Germany .
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Limbach, Renè
    University of Jena, Germany.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Wondraczek, Lothar
    University of Jena, Germany.
    Alkali salt vapour deposition and in-line ion exchange on flat glass surfaces2015In: European Journal of Glass Science and Technology. Part A: Glass Technology, ISSN 1753-3546, Vol. 56, no 6, p. 203-213Article in journal (Refereed)
    Abstract [en]

    This study suggests a different route for the modification of flat/float glass surfaces; i.e. exchange of ionic species originatingfrom in-line vapour deposition of salt as compared to the conventional route of immersing the glass in a molten saltbath. The aim of this work is to develop a more flexible and, eventually, more rapid process for improving the mechanicalstrength of flat glass by introducing external material into the surface. We discuss how chemical strengthening can beperformed through the application of potassium chloride on the glass surface by vapour deposition, and in-line thermallyactivated ion exchange. The method presented here has the potential to be up-scaled and to be used in in-line productionin the future, which would make it possible to produce large quantities of chemically strengthened flat glass at aconsiderably lower cost.

  • 200.
    Karlsson, Stefan
    et al.
    Glafo – the Glass Research Institute ; University of Jena, Germany.
    Grund Bäck, Lina
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Kidkhunthod, Pinit
    Synchrotron Light Research Institute, Thailand.
    Lundstedt, Karin
    Glafo – the Glass Research Institute.
    Wondraczek, Lothar
    University of Jena, Germany.
    Effect of TiO2 on optical properties of glasses in the soda-lime-silicate system2016In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 6, no 4, p. 1198-1216Article in journal (Refereed)
    Abstract [en]

    Titania is widely considered as an alternative constituent for replacing heavy metal oxides in optical glasses. Its effect on optical properties, however, is complex. This is due to the dielectric properties of the prevalent ionic species, Ti4+, the potential co-existence of trivalent titanium, Ti3+, giving rise to intrinsic and extrinsic charge transfer reactions, and the existence of different coordination polyhedra, depending on matrix composition. Here, we present a systematic study of the optical properties of the soda-lime-silicate glass system as a function of TiO2 addition. We consider the silica-rich region of the SiO2-Na2O-CaO-TiO2 quaternary, which may be taken as model for a variety of technical glasses. Trends are described in the refractive index, the Abbe number, the optical bandgap and the Urbach energy. The addition of TiO2 increases the refractive index and the optical dispersion while it lowers the optical bandgap and the Urbach Energy. Results are discussed in relation to relevant literature data towards using titania silicate glasses as high-index replacements for heavy metal containing oxide glasses. (C) 2016 Optical Society of America

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