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  • 1.
    Almhöjd, Ulrika S.
    et al.
    Sahlgrenska Academy, Sweden.
    Lingström, Peter
    Sahlgrenska Academy, Sweden.
    Nilsson, Åke
    Sahlgrenska Academy, Sweden.
    Noren, Jörgen G.
    Sahlgrenska Academy, Sweden.
    Siljeström, Silje
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry, Materials and Surfaces.
    ֖stlund, Å.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Bernin, D.
    University of Gothenburg, Sweden.
    Molecular Insights into Covalently Stained Carious Dentine Using Solid-State NMR and ToF-SIMS2017In: Caries Research, ISSN 0008-6568, E-ISSN 1421-976X, Vol. 51, no 3, p. 255-263Article in journal (Refereed)
    Abstract [en]

    Dyes currently used to stain carious dentine have a limited capacity to discriminate normal dentine from carious dentine, which may result in overexcavation. Consequently, finding a selective dye is still a challenge. However, there is evidence that hydrazine-based dyes, via covalent bonds to functional groups, bind specifically to carious dentine. The aim of this study was to investigate the possible formation of covalent bonds between carious dentine and 15N2-hydrazine and the hydrazine-based dye, 15N2-labelled Lucifer Yellow, respectively. Powdered dentine from extracted carious and normal teeth was exposed to the dyes, and the staining reactions were analysed using time-of-flight secondary ion mass spectrometry (ToF-SIMS), solid-state 13C-labelled nuclear magnetic resonance (NMR) and 15N-NMR spectroscopy. The results showed that 15N2-hydrazine and 15N2-labelled Lucifer Yellow both bind to carious dentine but not to normal dentine. It can thus be concluded that hydrazine-based dyes can be used to stain carious dentine and leave normal dentine unstained.

  • 2.
    Andersson, Sofia
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    Bengtsson, Andreas
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy. KTH Royal institute of technology, Sweden.
    Åkerström, Mårten
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Sedin, Maria
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Sjöholm, Elisabeth
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    The impact of inorganic elements on lignin‐based carbon fibre quality2018In: 15th European workshop on lignocelllulosics and pulp: Proceedings for poster presentations, 2018, p. 119-122Conference paper (Other academic)
    Abstract [en]

    The influence of inorganic elements on lignin ‐based carbon fibre (CF) quality was studied using sulphates of Na +, K+, Mg2+, Fe2+, Al3+. The metal sulphates were added to wet spun prefibres made from softwood kraft lignin (SKL):cellulose (70:30) and melt spun prefibres made from low molecular mass SKL. An increase in concentration from 0.1 w% to about 0.4 w% did neither affect the mechanical properties nor the morphology as observed by SEM. In contrast, metal sulphates added to the initial 0.45 w% to a total range 1.5 to 5.0 w%, was found detrimental to the melt spinning and to the final CF quality. Thus, the recommendation of <0.1 w% ash in kraft lignin may be exceeded, but more research is needed to establish the upper concentration limit.

  • 3.
    Anheden, Marie
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Kulander, Ida
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Pettersson, Karin
    Wallinder, Johan
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Vamling, Lennart
    Chalmers University of Technology, Sweden.
    Hjerpe, Carl Johan
    F Industri, Sweden.
    Fugelsang, Malin
    F Industri, Sweden.
    Håkansson, Åsa
    Preem, Sweden.
    Evaluation of alternative routes for production of bio-oil from forest residues and kraft lignin2018In: The 8th Nordic Wood Biorefinery Conference: NWBC 2018 : proceedings / [ed] Hytönen Eemeli, Vepsäläinen Jessica, Espoo: VTT , 2018, p. 85-89Conference paper (Refereed)
  • 4.
    Baker, Darren A
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Sedin, Maria
    Södra skogsägarna ekonomisk förening, Sweden.
    Landmer, Alice
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Friman, Linda
    Södra skogsägarna ekonomisk förening, Sweden.
    Echardt, Linda
    Södra skogsägarna ekonomisk förening, Sweden.
    Structural carbon fibre from kraft lignin2017In: The 7th Nordic Wood Biorefinery Conference held in Stockholm, Sweden, 28-30 Mar. 2017: NWBC 2017, Stockholm: RISE Bioekonomi , 2017, p. 65-67Conference paper (Refereed)
    Abstract [en]

    The GreenLight consortium is working to demonstrate a biobased, renewable and economically viable carbon fibre from lignin. The aim is to provide a basis for commercial production of lignin, lignin filaments, carbon fibre and carbon fibre composites. The most difficult boundary to success in the developing lignin as a precursor for continuous filament carbon fibre has been identified as melt extrusion of lignin. The consortium is working to develop a robust melt spinning platform for use up to the 1,000 filament scale. Methodical studies have been performed to examine lignin separation from differing black liquors derived from both softwood and hardwood and assess their viability in terms of thermal, compositional and structural properties. The move will then be made to pilot scale melt spinning at the 100 filament scale. The characteristics of some kraft lignin fractions obtained from the same Sodra Monsteras softwood kraft black liquor have been studied. The lignins were manufactured in quantities of approximately 10-20kg. Several variations of the LignoBoost process were used to provide lignins with improved melt spinning properties. The lignins were of high purity, each having low carbohydrate, extractives and inorganic contents. All four lignins could be melt spun and converted to carbon fibre.

  • 5.
    Balakshin, Mikhail
    et al.
    Aalto University, Finland.
    Capanema, Ewellyn A
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Huang, Zeen
    FP Innovations, Cananda.
    Sulaeva, Irina
    BOKU, Austria.
    Rojas, Orlando
    Aalto University, Finland.
    Feng, Martin
    FP Innovations, Canada.
    Rosenau, Thomas
    BOKU, Austria.
    Potthast, Antje
    BOKU, Austria.
    Recent achievement in the valorization of technical lignins2018In: The 8th Nordic Wood Biorefinery Conference: NWBC 2018 : proceedings / [ed] Hytönen Eemeli, Vepsäläinen Jessica, Espoo, 2018, p. 151-156Conference paper (Refereed)
  • 6.
    Bengtsson, Andreas
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy. KTH Royal institute of technology, Sweden.
    Sjöholm, Elisabeth
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    Conditions for the stabilisation of lignin-cellulose prefibres for carbon fibre production2018In: 15th European workshop on lignocellulosics and pulp: Proceedings for poster presentations, 2018, p. 111-114Conference paper (Other academic)
    Abstract [en]

    Stabilisation of the prefibre is a time-consuming step in carbon fibre (CF) production. In this paper the stabilisation condition of dry-jet wet-spun lignin-cellulose (LC) prefibres (70:30  t%) are reported. The impact of prefibre-impregnation by ammonium dihydrogen phosphate (ADHP) and various thermal conditions were evaluated by measuring the yield and mechanical properties of the final CFs. The addition of ADHP improved the CF yields from 32-40 wt% to 45-47 wt% but had a slight negative impact on the tensile modulus (TM) whereas no significant difference in tensile strength (TS) was observed. The absence of fibre fusion and glass transition temperature (Tg) indicate successful stabilisation of all prefibres. This implies possibilities of using short stabilisation times of LC prefibres in CF production.

  • 7.
    Borrega, Marc
    et al.
    Aalto university, Finland ; VTT Technical Research Centre of Finland Ltd, Finland.
    Larsson, Per Tomas
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Ahvenainen, Patrik
    University of Helsinki, Finland.
    Ceccherini, Sara
    Aalto university, Finland.
    Maloney, Thaddeus
    Aalto university, Finland.
    Rautkari, Lauri
    Aalto university, Finland.
    Sixta, Herbert
    Aalto university, Finland.
    Birch wood pre-hydrolysis vs pulp post-hydrolysis for the production of xylan-based compounds and cellulose for viscose application2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 190, p. 212-221Article in journal (Refereed)
    Abstract [en]

    Hydrothermal treatments of birch wood and kraft pulp were compared for their ability to extract the xylan and produce viscose-grade pulp. Water post-hydrolysis of kraft pulp produced a high-purity cellulosic pulp with lower viscosity but higher cellulose yield than traditional pre-hydrolysis kraft pulping of wood. Post-hydrolysis of pulp also increased the crystallite dimensions and degree of crystallinity in cellulose, and promoted a higher extent of fibril aggregation. The lower specific surface area in post-hydrolyzed pulps, derived from their larger fibril aggregates, decreased the accessibility of –OH groups. However, this lower accessibility did not seem to decrease the pulp reactivity to derivatizing chemicals. In the aqueous side-stream, the xylose yield was similar in both pre- and post-hydrolysates, although conducting post-hydrolysis of pulp in a flow-through system enabled the recovery of high purity and molar mass (∌10 kDa) xylan for high-value applications.

  • 8.
    Brännvall, Elisabet
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Increasing pulp yield in kraft cooking of softwoods by high initial effective alkali concentration (HIEAC) during impregnation leading to decreasing secondary peeling of cellulose2018In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 72, no 10, p. 819-827Article in journal (Refereed)
    Abstract [en]

    Pulp yield can be improved by a more homogeneous delignification of the chips, achieved by improved impregnation prior to the cooking stage. Complete and efficient impregnation is obtained by increasing the diffusion rate by means of an impregnation liquor with a high initial effective alkali concentration (HIEAC). In the present study, the effect of HIEAC in the impregnation was evaluated and compared to a reference impregnation procedure and a prolonged impregnation. After the various impregnation scenarios, the alkali concentration was always adjusted to the same level in the beginning of the cooking stage. Impregnation with a HIEAC resulted in yield improvements by 1-1.5% units, due to a higher cellulose yield and possibly also to higher yield of glucomannan. The HIEAC with an even alkali distribution within the chips prior to the cooking stage resulted in a more uniform delignification carbohydrate degradation. Yield increase obtained by uniform delignification is due to both decreased shives content as well as less secondary peeling.

  • 9.
    Brännvall, Elisabet
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Reimann, Anders
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    The balance between alkali diffusion and alkali consuming reactions during impregnation of softwood. Impregnation for kraft pulping revisited2018In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 72, no 3, p. 169-178Article in journal (Refereed)
    Abstract [en]

    The purpose of the impregnation stage is to ensure that cooking chemicals reach all parts of the chips. However, as alkali comes into contact with wood, reactions take place, which alter the paths available for ionic transport and dissolve wood components. The aim of the present study is to establish the most favorable impregnation conditions, which result in an even alkali concentration profile through the chip at a sufficiently high level without extensive yield losses due to peeling. Softwood chips were subjected to different impregnation conditions. The progress of impregnation was assessed by analyzing the concentration of hydroxide ions in the bound liquor inside wood chips and the release of acetic acid. The extent of undesired reactions was measured as the amount of carbohydrate degradation products formed and amount of wood dissolved. Increased temperature and time lead to more degradation of the carbohydrates during impregnation. At high temperature, the concentration of alkali in the bound liquor was lower due to higher alkali consumption in degradation reactions. The most favorable process is to perform impregnation at an elevated initial effective alkali (EA) for a short time. This resulted in an increased alkali concentration in the bound liquor within the chip without extensive carbohydrate degradation.

  • 10.
    Carlmark, Anna
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Modification of nanocellulose with tailored latex nanoparticles2018In: Recent advances in cellulose nanotechnology research: production, characterization and applications, Trondheim: RISE PFI , 2018Conference paper (Other academic)
  • 11.
    Carvalho, Lara
    et al.
    Luleå University of Technology, Sweden.
    Lundgren, Joakim
    Luleå University of Technology, Sweden ; International Institute for Applied Systems Analysis (IIASA), Austria.
    Wetterlund, Elisabeth
    Luleå University of Technology, Sweden ; International Institute for Applied Systems Analysis (IIASA), Austria.
    Wolf, Jens
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Furusjö, Erik
    Luleå University of Technology, Sweden ; IVL Swedish Environmental Institute, Sweden.
    Methanol production via black liquor co-gasification with expanded raw material base – Techno-economic assessment2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 225, p. 570-584Article in journal (Refereed)
    Abstract [en]

    Entrained flow gasification of black liquor combined with downstream-gas-derived synthesis of biofuels in Kraft pulp mills has shown advantages regarding energy efficiency and economic performance when compared to combustion in a recovery boiler. To further increase the operation flexibility and the profitability of the biofuel plant while at the same time increase biofuel production, black liquor can be co-gasified with a secondary feedstock (blend-in feedstock). This work has evaluated the prospects of producing biofuels via co-gasification of black liquor and different blend-in feedstocks (crude glycerol, fermentation residues, pyrolysis liquids) at different blend ratios. Process modelling tools were used, in combination with techno-economic assessment methods. Two methanol grades, crude and grade AA methanol, were investigated. The results showed that the co-gasification concepts resulted in significant increases in methanol production volumes, as well as in improved conversion efficiencies, when compared with black liquor gasification; 5–11 and 4–10 percentage point in terms of cold gas efficiency and methanol conversion efficiency, respectively. The economic analysis showed that required methanol selling prices ranging from 55 to 101 €/MWh for crude methanol and 58–104 €/MWh for grade AA methanol were obtained for an IRR of 15%. Blend-in led to positive economies-of-scale effects and subsequently decreased required methanol selling prices, in particular for low cost blend-in feedstocks (prices below approximately 20 €/MWh). The co-gasification concepts showed economic competitiveness to other biofuel production routes. When compared with fossil fuels, the resulting crude methanol selling prices were above maritime gas oil prices. Nonetheless, for fossil derived methanol prices higher than 80 €/MWh, crude methanol from co-gasification could be an economically competitive option. Grade AA methanol could also compete with taxed gasoline. Crude glycerol turned out as the most attractive blend-in feedstock, from an economic perspective. When mixed with black liquor in a ratio of 50/50, grade AA methanol could even be cost competitive with untaxed gasoline.

  • 12.
    de la Motte, Hanna
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Circular recycling of cotton fibers recovered from polyester/cotton textile blends2018Conference paper (Other academic)
  • 13.
    Englund, Finn
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Wedin, Helena
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Ribul, Miriam
    London Doctoral Design Centre (LDoC), UK.
    de la Motte, Hanna
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Östlund, Åsa
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Textile tagging to enable automated sorting and beyond: a report to facilitate an active dialogue within the circular textile industry2018Report (Other academic)
  • 14.
    Fall, Andreas
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Nanocellulose and graphene: promising hybrid materials2018In: Recent advances in cellulose nanotechnology research: production, characterization and applications, Trondheim: RISE PFI , 2018Conference paper (Refereed)
  • 15.
    Frishammar, Johan
    et al.
    Luleå University of Technology, Sweden.
    Söderholm, Patrik
    Luleå University of Technology, Sweden.
    Hellsmark, Hans
    Chalmers University of Technology, Sweden.
    Mossberg, Johanna
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    A Knowledge-based Perspective on System Weaknesses in Technological Innovation Systems2018In: Science and Public Policy, ISSN 0302-3427, E-ISSN 1471-5430Article in journal (Refereed)
    Abstract [en]

    The literature on technological innovation systems (TIS) provides policymakers and other actors with a scheme of analysis to identify system weaknesses. In doing so, TIS analysis centres on which system weaknesses policy interventions should target to promote further development of a particular system. However, prior TIS literature has not sufficiently elaborated on what may constitute the conceptual roots of a ‘weakness’. We apply a knowledge-based perspective and propose that many—albeit not all—system weaknesses may root in four types of knowledge problems: uncertainty, complexity, equivocality, and ambiguity. Employing these as sensitizing concepts, we study system weaknesses by analysing data from a biorefinery TIS in Sweden. This analysis results in novel implications for the TIS literature and for achieving a better match between system weaknesses and the design of innovation policies.

  • 16.
    Gao, Yu
    et al.
    Washington University, US.
    Walker, Michael J
    Washington University, US.
    Barrett, Jacob A
    University of California, US.
    Hosseinaei, Omid
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Harper, David P
    University of Tennessee, US.
    Ford, Peter C
    University of California, US.
    Williams, Brent J
    Washington University, US.
    Foston, Marcus B
    Washington University, US.
    Analysis of gas chromatography/mass spectrometry data for catalytic lignin depolymerization using positive matrix factorization2018In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 20, no 18, p. 4366-4377Article in journal (Refereed)
    Abstract [en]

    Various catalytic technologies are being developed to efficiently convert lignin into renewable chemicals. However, due to its complexity, catalytic lignin depolymerization often generates a wide and complex distribution of product compounds. Gas chromatography/mass spectrometry (GC-MS) is a common analytical technique to profile the compounds that comprise lignin depolymerization products. GC-MS is applied not only to determine the product composition, but also to develop an understanding of the catalytic reaction pathways and of the relationships among catalyst structure, reaction conditions, and the resulting compounds generated. Although a very useful tool, the analysis of lignin depolymerization products with GC-MS is limited by the quality and scope of the available mass spectral libraries and the ability to correlate changes in GC-MS chromatograms to changes in lignin structure, catalyst structure, and other reaction conditions. In this study, the GC-MS data of the depolymerization products generated from organosolv hybrid poplar lignin using a copper-doped porous metal oxide catalyst and a methanol/dimethyl carbonate co-solvent was analyzed by applying a factor analysis technique, positive matrix factorization (PMF). Several different solutions for the PMF model were explored. A 13-factor solution sufficiently explains the chemical changes occurring to lignin depolymerization products as a function of lignin, reaction time, catalyst, and solvent. Overall, seven factors were found to represent aromatic compounds, while one factor was defined by aliphatic compounds.

  • 17.
    Goldsworthy, Kate
    et al.
    University of the Arts London.
    Roos, Sandra
    RISE - Research Institutes of Sweden, Swerea.
    Sandin, Gustav
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Peters, Greg
    Chalmers University of Technology.
    Towards a Quantified Design Process: Bridging Design and Life Cycle Assessment2016Conference paper (Other academic)
    Abstract [en]

    In this paper we describe how design researchers and environmental researchers are making a joint effort in overcoming the disciplinary barriers for collaboration. By comparing existing processes and identifying potential opportunities arising from inter-disciplinary collaboration the aim is to propose methods for building a bridge between disciplines. A model for “quantified design” is generated, and explored, relevant for designers, design researchers as well as LCA researchers.

  • 18.
    Gunnarsson, Maria
    et al.
    Chalmers University of technology, Sweden.
    Bernin, Diana
    Chalmers University of technology, Sweden.
    Östlund, Åsa
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Hasani, Merima
    Chalmers University of technology, Sweden.
    CO2 capturing and the influence on cellulose dissolution in the NaOH(aq) system2018In: 15th European workshop on lignocellulosics and pulp: Proceedings for poster presentations, 2018, p. 419-422Conference paper (Refereed)
    Abstract [en]

    The narrow dissolution window for cellulose in NaOH(aq) is a limiting factor in the production of regenerated cellulose materials, which is why understanding of the molecular interactions in this solvent system is of the highest importance. In this work, we highlight the interaction between cellulose and CO2 in NaOH(aq). The model compound methyl α-D-glycopyranoside (MeO-Glcp) was used to compare the difference of the dissolved state in NaCl(aq) and NaOH(aq), including both pre and post-dissolution addition of CO2. N MR a nd A TR-IR  spectroscopy as well as ocular observations were used in the evaluation.  1H and 13C NMR spectroscopy showed a clear change in chemical shift of the MeO-Glcp when dissolved in NaOH(aq) compared to NaCl(aq), which is a result of deprotonation. Interestingly, the addition of CO2 either pre or post-dissolution of MeO-Glcp in NaOH(aq) affected the chemical shifts differently (apart from the expected change in pH). With quantitative 13C NMR measurements, the uptake of CO2 was found to be more than twice as high when the CO2 was added post-dissolution of MeO-Glcp in NaOH(aq) compared to prior to dissolution. This suggests that specific interactions occur between CO2 and MeO-Glcp when the latter is dissolved prior to the addition of CO2, which could be attributed to the deprotonated state of MeO-Glcp. Furthermore, the dissolved state of cellulose in NaOH(aq) was visually shown to iffer in terms of pre or post-dissolution addition of CO2. Post-dissolution addition of CO2 resulted in the formation of a gelled structure when solutions was left to age in room temperature for two weeks. ATR-IR spectroscopy of materials regenerated from the aged solutions confirmed the introduction of a n ew waveband corresponding to CO2 out-of-phase stretching confirming the sorption of CO2 on cellulose when dissolved in NaOH(aq).

  • 19.
    Gunnarsson, Maria
    et al.
    Chalmers University of Technology, Sweden.
    Bernin, Diana
    University of Gothenburg, Sweden ; Chalmers University of Technology, Sweden.
    Östlund, Åsa
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Hasani, Merima
    Chalmers University of Technology, Sweden.
    The CO2 capturing ability of cellulose dissolved in NaOH(aq) at low temperature2018In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 20, no 14, p. 3279-3286Article in journal (Refereed)
    Abstract [en]

    Herein, we explore the intrinsic ability of cellulose dissolved in NaOH(aq) to reversibly capture CO2. The stability of cellulose solutions differed significantly when adding CO2 prior to or after the dissolution of cellulose. ATR-IR spectroscopy on cellulose regenerated from the solutions, using ethanol, revealed the formation of a new carbonate species likely to be cellulose carbonate. To elucidate the interaction of cellulose with CO2 at the molecular level, a 13C NMR spectrum was recorded on methyl α-d-glucopyranoside (MeO-Glcp), a model compound, dissolved in NaOH(aq), which showed a difference in chemical shift when CO2 was added prior to or after the dissolution of MeO-Glcp, without a change in pH. The uptake of CO2 was found to be more than twice as high when CO2 was added to a solution after the dissolution of MeO-Glcp. Altogether, a mechanism for the observed CO2 capture is proposed, involving the formation of an intermediate cellulose carbonate upon the reaction of a cellulose alkoxide with CO2. The intermediate was observed as a captured carbonate structure only in regenerated samples, while its corresponding NMR peak in solution was absent. The reason for this is plausibly a rather fast hydrolysis of the carbonate intermediate by water, leading to the formation of CO3 2-, and thus increased capture of CO2. The potential of using carbohydrates as CO2 capturing agents in NaOH(aq) is shown to be simple and resource-effective in terms of the capture and regeneration of CO2.

  • 20.
    Guo, Juan
    et al.
    Chinese Academy of Forestry, China.
    Zhou, Haibin
    Chinese Academy of Forestry, China.
    Stevanic Srndovic, Jasna
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Dong, Mengyu
    Chinese Academy of Forestry, China.
    Yu, Min
    Chinese Academy of Forestry, China.
    Salmen, Lennart
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Yin, Yafang
    Chinese Academy of Forestry, China.
    Effects of ageing on the cell wall and its hygroscopicity of wood in ancient timber construction2018In: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 52, no 1, p. 131-147Article in journal (Refereed)
    Abstract [en]

    An important traditional load bearing member in oriental ancient timber structure buildings, i.e. Huagong (flower arm), was selected to explore the alterations in cell wall components and hygroscopic properties of wood during long time ageing. This archaeological poplar (Populus spp.) wood with cal. BP 690: BP 790 was studied from the wood surface and inwards by means of imaging FTIR spectroscopy, X-ray diffraction and dynamic vapour sorption. The deterioration of the archaeological wood mainly displayed a depolymerization of glucomannan and lignin as well as a hydrolysis of the glucuronic acid of xylan and of the aromatic C–O groups in the condensed lignins or lignin–carbohydrate complexes. Furthermore, the degradation promoted the rearrangement of the cellulose molecules in adjacent microfibrils. The cellulose crystallites in the archaeological wood were therefore packed more tightly and had larger diameter. The structural alterations of wood cell wall components and a decrease in crystallinity contributed to an increase in the number of moisture bonding sites and led to an increase in both the equilibrium moisture content of the archaeological wood in the entire RH range as well as an increase in hysteresis.

  • 21.
    Guo, Zengwei
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    Lindqvist, Karin
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    de la Motte, Hanna
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    An efficient recycling process of glycolysis of PET in the presence of a sustainable nanocatalyst2018In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 135, no 21, article id 46285Article in journal (Refereed)
    Abstract [en]

    We demonstrate that the catalyst Perkalite F100 efficiently works as a nanocatalyst in the depolymerization of poly(ethylene terephthalate) (PET). After depolymerization of PET in the presence of ethylene glycol and the Perkalite nanocatalyst, the main product obtained was bis(2-hydroxylethyl) terephthalate (BHET) with high purity, as confirmed by Fourier transform infrared spectroscopy and NMR. The BHET monomers could serve directly as starting materials in a further polymerization into PET with a virgin quality and contribute to a solution for the disposal of PET polymers. Compared with the direct glycolysis of PET, the addition of a predegradation step was shown to reduce the reaction time needed to reach the depolymerization equilibrium. The addition of the predegradation step also allowed lower reaction temperatures. Therefore, the strategy to include a predegradation step before depolymerization is suitable for increasing the efficiency of the glycolysis reaction of PET into BHET monomers.

  • 22.
    Göhl, Johan
    et al.
    Fraunhofer-Chalmers Centre, Sweden.
    Markstedt, Kajsa
    Wallenberg Wood Science Center, Sweden ; Chalmers University of Technology, Sweden.
    Mark, Andreas
    Fraunhofer-Chalmers Centre, Sweden.
    Håkansson, Karl
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy. Wallenberg Wood Science Center, Sweden ; Chalmers University of Technology, Sweden.
    Gatenholm, Paul
    Wallenberg Wood Science Center, Sweden ; Chalmers University of Technology, Sweden.
    Edelvik, Fredrik
    Fraunhofer-Chalmers Centre, Sweden.
    Simulations of 3D bioprinting: Predicting bioprintability of nanofibrillar inks2018In: Biofabrication, ISSN 1758-5082, E-ISSN 1758-5090, Vol. 10, no 3, article id 034105Article in journal (Refereed)
    Abstract [en]

    3D bioprinting with cell containing bioinks show great promise in the biofabrication of patient specific tissue constructs. To fulfil the multiple requirements of a bioink, a wide range of materials and bioink composition are being developed and evaluated with regard to cell viability, mechanical performance and printability. It is essential that the printability and printing fidelity is not neglected since failure in printing the targeted architecture may be catastrophic for the survival of the cells and consequently the function of the printed tissue. However, experimental evaluation of bioinks printability is time-consuming and must be kept at a minimum, especially when 3D bioprinting with cells that are valuable and costly. This paper demonstrates how experimental evaluation could be complemented with computer based simulations to evaluate newly developed bioinks. Here, a computational fluid dynamics simulation tool was used to study the influence of different printing parameters and evaluate the predictability of the printing process. Based on data from oscillation frequency measurements of the evaluated bioinks, a full stress rheology model was used, where the viscoelastic behaviour of the material was captured. Simulation of the 3D bioprinting process is a powerful tool and will help in reducing the time and cost in the development and evaluation of bioinks. Moreover, it gives the opportunity to isolate parameters such as printing speed, nozzle height, flow rate and printing path to study their influence on the printing fidelity and the viscoelastic stresses within the bioink. The ability to study these features more extensively by simulating the printing process will result in a better understanding of what influences the viability of cells in 3D bioprinted tissue constructs.

  • 23.
    Haeggman, Marika
    et al.
    Albaeco, Sweden.
    Moberg, Fredrik
    Albaeco, Sweden.
    Sandin, Gustav
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Planetary Boundaries analysis for Houdini Sportswear – a Pilot Study: Assessment of company performance from a planetary boundaries perspective2018In: Planetary Boundaries Assessment 2018 – This is Houdini, Houdini Sportswear , 2018, p. 37-66Chapter in book (Other (popular science, discussion, etc.))
    Abstract [en]

    This is to our knowledge the first ever corporate Planetary Boundaries analysis. It is an explorative collaboration between Houdini Sportswear, Albaeco and Mistra Future Fashion with the long-term ambition to create an open-source approach that will provide Houdini and other similar companies with a more holistic view on their sustainability efforts. Albaeco is closely tied to the Stockholm Resilience Centre (SRC), an international research centre for sustainability science at Stockholm University, known among other things for its work on planetary boundaries, resilience and ecosystem services.

    This report aims to operationalize the Planetary Boundaries framework in a business context. The framework was established in 2009 when a group of scientists (Rockström and others, 2009) identified nine global environmental boundaries we should remain within so that our societies can continue to develop in a positive way. As such the Planetary Boundaries provide a holistic way of analysing sustainability that has acquired international recognition and contributed to the UN’s Sustainable Development Goals (SDGs). Rather than a narrow focus on for example water, chemicals or energy use, a planetary boundaries approach implies covering a larger set of critical environmental factors.

    The manufacturing and consumption of clothes, like every other industry, plays a role in relation to all of the nine boundaries. For example, cotton is one of the most pesticide and water demanding crops grown; chemicals used when treating fabrics risk polluting water downstream from factories; and shell layer garments are often produced using compounds that stay in the environmental indefinitely and accumulate in the fatty tissues of wildlife and humans

    Albaeco, Houdini and Mistra Future Fashion believe that analysing the textile industry from a Planetary Boundaries perspective is an important part of a larger ambition to integrate scientific analysis and resilience thinking into projects focused on accelerating business solution for sustainability.

  • 24.
    Hellström, Anna-Karin
    et al.
    Chalmers, Gothenburg, Sweden.
    de la Motte, Hanna
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Syrén, Marie
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Nordstierna, Lars
    Bordes, Romain
    Enabling Textile Recycling: On/Off Dyeing2016Conference paper (Other academic)
    Abstract [en]

    Develop a novel family of environmental friendly dispersant for textile coloring embedded an on/off function for closed loop recycling.

  • 25.
    Hosseinaei, Omid
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Electrospun lignin-based carbon fibers for energy storage application2018In: The 8th Nordic Wood Biorefinery Conference: NWBC 2018 : proceedings / [ed] Hytönen Eemeli, Vepsäläinen Jessica, Espoo: VTT , 2018, p. 244-244Conference paper (Other academic)
  • 26.
    Hosseinaei, Omid
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Åkerström, Mårten
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Uhlin, Anders
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Tomani, Per
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Danielsson, Sverker
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Melt spun lignin-based carbon fiber from softwood kraft lignin: effect of lignin pretreatment and fiber conversion conditions2018In: The 8th Nordic Wood Biorefinery Conference: NWBC 2018 : proceedings / [ed] Hytönen Eemeli, Vepsäläinen Jessica, Espoo: VTT , 2018, p. 157-163Conference paper (Other academic)
  • 27.
    Jafri, Yawer
    et al.
    Luleå University of Technology, Sweden.
    Wetterlund, Elisabeth
    Luleå University of Technology, Sweden.
    Anheden, Marie
    Kulander, Ida
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Håkansson, Åsa
    Preem AB, Sweden.
    Furusjö, Erik
    Luleå University of Technology, Sweden ; IVL Swedish Environmental Research Institute, Sweden.
    Multi-aspect evaluation of integrated forest-based biofuel production pathways: Part 1. Product yields & energetic performance2019In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 166, p. 401-413Article in journal (Refereed)
    Abstract [en]

    Forest-based biofuels are strategically important in forest-rich countries like Sweden but the technical performance of several promising production pathways is poorly documented. This study examines product yields and energy efficiencies in six commercially relevant forest-based “drop-in” and “high blend” biofuel production pathways by developing detailed spreadsheet energy balance models. The models are in turn based on pilot-scale performance data from the literature, supplemented with input from technology developers and experts. In most pathways, biofuel production is integrated with a market pulp mill and/or a crude oil refinery. Initial conversion is by pyrolysis, gasification or lignin depolymerization and intermediate products are upgraded by hydrotreatment or catalytic synthesis. While lignin oil (LO) hydrodeoxygenation had the highest expanded system efficiency, considerable uncertainty surrounds product yields owing to absence of suitable experimental data on LO upgrading. Co-feeding vacuum gas oil and fast pyrolysis oil in a fluidized catalytic cracker has a complex and uncertain effect on fossil yields, which requires further investigation. Co-locating bio-oil hydrotreatment at the refinery improves heat utilization, leading to higher system efficiencies. Explicit consideration of mill type and energy requirements is required to avoid performance misestimation as an assumption of energy surplus can confer a definite advantage.

  • 28.
    Jour, Pia
    et al.
    Akzo Nobel Pulp and Performance Chemicals.
    Lindgren, Karin
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Gutke, Katarina
    Akzo Nobel Pulp and Performance Chemicals.
    ECF bleaching of eucalyptus kraft pulp: simulation of a mill with a high degree of closure2017In: International pulp bleaching conference / [ed] Colodette J L, Gomes F J B, Suprema Grafica e Editora , 2017, p. 106-110Conference paper (Other academic)
    Abstract [en]

    The composition of non-process elements (NPEs) in wood significantly affects the level of metals in the pulp in the bleach plant and contributes to the risk of forming precipitates. The possible degree of closure is often limited by calcium oxalate formation, mainly around the D0-stage, which can be prevented by increasing the temperature and/or decreasing the pH in this stage. This paper presents the effect of a decreased pH in the D0-stage when bleaching a eucalyptus kraft pulp as well as the influence it has on environmental parameters such as chemical oxygen demand (COD) and adsorbable organic halogens (AOX). The increased AOX measured when applying a low pH in the D0-stage was shown to be easily decomposed under process conditions. To be able to predict the effect on both the recovery cycle and the bleach plant itself as a consequence of increased closure of the bleach plant, a full mill simulation model (WinGEMS) was used based on a theoretical mill using the best available technology (BAT) in combination with data produced in laboratory trials. The model pulp mill was exclusively equipped with wash presses. According to the simulations, the effluent volume could be significantly decreased from 20.7 t/air dry tonne (ADt) pulp to 8.7 t/ADt in a D(EOP)DP sequence. Using a wood raw material with a calcium content of 520 mg/kg dry solids, no formation of calcium oxalate was predicted. However, for a wood raw material with a higher content, 800 mg/kg, calcium oxalate formation was likely to occur. By decreasing the final pH in the D0-stage from 3.0 to 2.5, formation of calcium oxalate could be avoided. At the effluent volume of 8.7 t/ADt, no fresh water was used in the bleach plant except for the water used for dilution of chemicals.

  • 29.
    Kaldeus, Tahani
    et al.
    Wallenberg Wood Science Center, Sweden.
    Larsson, Per Tomas
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Boujemaoui, Assya
    KTH Royal institute of technology, Sweden.
    Malmström, Eva
    KTH Royal institute of technology, Sweden.
    One-pot preparation of bi-functional cellulose nanofibrils2018In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882XArticle in journal (Refereed)
    Abstract [en]

    Herein, we present a route to obtain bi-functional cellulose nanofibrils (CNF) by a one-pot approach using an already established functionalisation route, carboxymethylation, to which a subsequent functionalisation step, allylation or alkynation, has been added in the same reaction pot, eliminating the need of solvent exchange procedures. The total charge of the fibres and the total surface charge of the nanofibrils were determined by conductometric and polyelectrolyte titration, respectively. Furthermore, the allyl and alkyne functionalised cellulose were reacted with methyl 3-mercaptopropionate and azide-functionalised disperse red, respectively, to estimate the degree of functionalisation. The samples were further assessed by XPS and FT-IR. Physical characteristics were evaluated by CP/MAS 13C-NMR, XRD, AFM and DLS. This new approach of obtaining bi-functionalised CNF allows for a facile and rapid functionalisation of CNF where chemical handles can easily be attached and used for further modification of the fibrils. Graphical abstract: [Figure not available: see fulltext.

  • 30.
    Karasu, Feyza
    et al.
    École Polytechnique Fédérale de Lausanne (EPFL), Switzerland.
    Müller, Luca
    École Polytechnique Fédérale de Lausanne (EPFL), Switzerland.
    Ridaoui, Hassan
    Rolic Technologies Ltd, Switzerland.
    Ibn ElHaj, Mohammed
    Rolic Technologies Ltd, Switzerland.
    Flodberg, Göran
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Aulin, Christian
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Axrup, Lars
    Stora Enso Karlstad, Sweden.
    Leterrier, Yves
    École Polytechnique Fédérale de Lausanne (EPFL), Switzerland.
    Organic-inorganic hybrid planarization and water vapor barrier coatings on cellulose nanofibrils substrates2018In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 6, article id 571Article in journal (Refereed)
    Abstract [en]

    Cellulose nanofibrils (CNF) can be produced in the form of thin, transparent andflexible films. However, the permeability of such materials to oxygen and water vaporis very sensitive to moisture, which limits their potential for a variety of packaging andencapsulation applications. Diffusion barrier coatings were thus developed to reducethe access of water molecules to enzymatically pre-treated and carboxymethylated CNFsubstrates. The coatings were based on UV curable organic-inorganic hybrids withepoxy, tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethylenesilane (GPTS)precursors and additional vapor formed SiNx layers. A total of 14 monolayer andmultilayer coatings with various thickness and hybrid composition were produced andanalyzed. The water vapor transmission rate (WVTR) of the bilayer epoxy/CNF film wastwo times lower compared to that of uncoated CNF film. This was partly due to the watervapor permeability of the epoxy, a factor of two times lower than CNF. The epoxy coatingimproved the transparency of CNF, however it did not properly wet to the CNF surfacesand the interfacial adhesion was low. In contrast hybrid epoxy-silica coatings led to highadhesion levels owing to the formation of covalent interactions through condensationreactions with the OH-terminated CNF surface. The barrier and optical performance ofhybrid coated CNF substrates was similar to that of CNF coated with pure epoxy. Inaddition, the hybrid coatings provided an excellent planarization effect, with roughnessclose to 1 nm, one to two orders of magnitude lower than that of the CNF substrates.The WVTR and oxygen transmission rate values of the hybrid coated CNF laminateswere in the range 5–10 g/m2/day (at 38◦C and 50% RH) and 3–6 cm3/m2/day/bar (at23◦C and 70% RH), respectively, which matches food and pharmaceutical packagingrequirements. The permeability to water vapor of the hybrid coatings wasmoreover foundto decrease with increasing the TEOS/GPTS ratio up to 30 wt% and then increase athigher ratio, and to be much lower for thinner coatings due to further UV-induced silanolcondensation and faster evaporation of byproducts. The addition of a single 150 nmthickSiNx layer on the hybrid coated CNF improved its water vapor barrier performance bymore than 680 times, with WVTR below the 0.02 g/m2/day detection limit.

  • 31.
    Karlsson, Rose-Marie Pernilla
    et al.
    KTH Royal Institute of Technology, Sweden.
    Larsson, Per Tomas
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy. KTH Royal Institute of Technology, Sweden.
    Yu, Shun
    KTH Royal Institute of Technology, Sweden.
    Pendergraph, Samuel Allen
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Pettersson, Torbjörn
    KTH Royal Institute of Technology, Sweden.
    Hellwig, Johannes
    KTH Royal Institute of Technology, Sweden.
    Wågberg, Lars
    KTH Royal Institute of Technology, Sweden.
    Carbohydrate gel beads as model probes for quantifying non-ionic and ionic contributions behind the swelling of delignified plant fibers.2018In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 519, p. 119-129, article id S0021-9797(18)30200-5Article in journal (Refereed)
    Abstract [en]

    Macroscopic beads of water-based gels consisting of uncharged and partially charged β-(1,4)-d-glucan polymers were developed to be used as a novel model material for studying the water induced swelling of the delignified plant fiber walls. The gel beads were prepared by drop-wise precipitation of solutions of dissolving grade fibers carboxymethylated to different degrees. The internal structure was analyzed using Solid State Cross-Polarization Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance and Small Angle X-ray Scattering showing that the internal structure could be considered a homogeneous, non-crystalline and molecularly dispersed polymer network. When beads with different charge densities were equilibrated with aqueous solutions of different ionic strengths and/or pH, the change in water uptake followed the trends expected for weak polyelectrolyte gels and the trends found for cellulose-rich fibers. When dried and subsequently immersed in water the beads also showed an irreversible loss of swelling depending on the charge and type of counter-ion which is commonly also found for cellulose-rich fibers. Taken all these results together it is clear that the model cellulose-based beads constitute an excellent tool for studying the fundamentals of swelling of cellulose rich plant fibers, aiding in the elucidation of the different molecular and supramolecular contributions to the swelling.

  • 32.
    Lecourt, Micheal
    et al.
    FCBA, France.
    Pöhler, Tiina
    VTT, Finland.
    Hornatowska, Joanna
    RISE - Research Institutes of Sweden, Bioeconomy.
    Salmen, Lennart
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Jetsu, Petri
    VTT, Finland.
    Density profiles of novel kraft pulp and TMP based foam formed thermal insulation materials observed by X-ray tomography and densitometry2018In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 72, no 5, p. 397-403Article in journal (Refereed)
    Abstract [en]

    X-ray tomography and densitometry (XRT and XRD) were applied to characterise wood fibre based insulation materials, which were produced by the foam forming technology. XRT is a high resolution approach with long measurement times of around 29 h, while XRD measurement needs only a few minutes. The determination of density distribution of boards in the thickness direction was the focus of this study. Both approaches visualised well the impact of raw materials and manufacturing processes on the structure of the panels. The density profiles were dependent on the pulp applied for panel production, and the processing conditions were also influential. Air flow resistance correlated with the maximum density measured inside the board. Both XRT and XRD revealed similar trends, which are useful for the characterisation of insulation materials.

  • 33.
    Lindberg, Anders
    et al.
    KTH Royal institute of technology, Sweden.
    Alfthan, Johan
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Pettersson, Henrik
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    Flodberg, Göran
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Yang, Li
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Mechanical performance of polymer powder bed fused objects: FEM simulation and verification2018In: Additive manufacturing, ISSN 2214-8604, Vol. 24, p. 577-586Article in journal (Refereed)
    Abstract [en]

    Additive manufacturing (3D printing) enables the designing and producing of complex geometries in a layer-by-layer approach. The layered structure leads to anisotropic behaviour in the material. To accommodate anisotropic behaviour, geometrical optimization is needed so that the 3D printed object meets the pre-set strength and quality requirements. In this article a material description for polymer powder bed fused also or selective laser sintered (SLS) PA12 (Nylon-12), which is a common 3D printing plastic, was investigated, using the Finite Element Method (FEM). The Material Model parameters were obtained by matching them to the test results of multipurpose test specimens (dumb-bells or dog bones) and the model was then used to simulate/predict the mechanical performance of the SLS printed lower-leg prosthesis components, pylon and support. For verification purposes, two FEM designs for a support were SLS printed together with additional test specimens in order to validate the used Material Model. The SLS printed prosthesis pieces were tested according to ISO 10328 Standard. The FEM simulations, together with the Material Model, was found to give good estimations for the location of a failure and its load. It was also noted that there were significant variations among individual SLS printed test specimens, which impacted on the material parameters and the FEM simulations. Hence, to enable reliable FEM simulations for the designing of 3D printed products, better control of the SLS process with regards to porosity, pore morphology and pore distribution is needed.

  • 34.
    Lindgren, Karin
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Kulander, Ida
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Törngren, Per
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Bialik, Marta
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Soap separation: a new option for removal of NPEs2018In: Technical solutions for today and beyond: TAPPI PEERS conference, 2018, p. 154-159Conference paper (Other academic)
  • 35.
    Liu, Yingxin
    et al.
    Stockholm University, Sweden ; KTH Royal Institute of Technology, Sweden.
    Stoeckel, Daniela
    Stockholm University, Sweden.
    Gordeyeva, Kornelya
    Stockholm University, Sweden.
    Agthe, Michael
    Stockholm University, Sweden.
    Schutz, Christina
    Stockholm University, Sweden.
    Fall, Andreas B.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy. Stockholm University, Sweden.
    Bergstrom, Lennart
    Stockholm University, Sweden.
    Nanoscale Assembly of Cellulose Nanocrystals during Drying and Redispersion2018In: ACS Macro Letters, E-ISSN 2161-1653, Vol. 7, no 2, p. 172-177Article in journal (Refereed)
    Abstract [en]

    We have followed the structural evolution during evaporation-induced self-assembly of sulfonated cellulose nanocrystal (CNC) in the presence of H+ and Li+ counterions by small-angle X-ray scattering. Drying of CNC-H dispersions results in ordered films that could not be readily redispersed, while the CNC-Li films were disordered and prone to reswelling and redispersion. The scaling of the separation distance (d) between CNC particles and the particle concentration (c) shows that the CNC-H dispersions display a unidimensional contraction of the nematic structure (d alpha c(-1)) during drying, while the CNC-Li dispersions consolidate isotropically (d alpha c(-1/3)), which is characteristic for hydrogels with no preferential orientation. Temporal evolution of the structure factor and complementary dynamic light-scattering measurements show that CNC-Li is more aggregated than CNC-H during evaporation-induced assembly. Insights on the structural evolution during CNC assembly and redispersion can promote development of novel and optimized processing routes of nanocellulose-based materials.

  • 36.
    Lo Re, Giada
    et al.
    KTH Royal Institute of Technology, Sweden.
    Spinella, Stephen
    NYU Tandon School of Engineering, US.
    Boujemaoui, Assya
    KTH Royal Institute of Technology, Sweden.
    Vilaseca, Fabiola
    University of Girona, Italy.
    Larsson, Per Tomas
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy. KTH Royal Institute of Technology, Sweden.
    Adås, Fredrik
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Berglund, Lars A.
    KTH Royal Institute of Technology, Sweden.
    Poly(ϵ-caprolactone) Biocomposites Based on Acetylated Cellulose Fibers and Wet Compounding for Improved Mechanical Performance2018In: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 6, no 5, p. 6753-6760Article in journal (Refereed)
    Abstract [en]

    Poly(ϵ-caprolactone) (PCL) is a ductile thermoplastic, which is biodegradable in the marine environment. Limitations include low strength, petroleum-based origin, and comparably high cost. Cellulose fiber reinforcement is therefore of interest although uniform fiber dispersion is a challenge. In this study, a one-step wet compounding is proposed to validate a sustainable and feasible method to improve the dispersion of the cellulose fibers in hydrophobic polymer matrix as PCL, which showed to be insensitive to the presence of the water during the processing. A comparison between unmodified and acetylated cellulosic wood fibers is made to further assess the net effect of the wet feeding and chemical modification on the biocomposites properties, and the influence of acetylation on fiber structure is reported (ATR-FTIR, XRD). Effects of processing on nanofibrillation, shortening, and dispersion of the cellulose fibers are assessed as well as on PCL molar mass. Mechanical testing, dynamic mechanical thermal analysis, FE-SEM, and X-ray tomography is used to characterize composites. With the addition of 20 wt % cellulosic fibers, the Young's modulus increased from 240 MPa (neat PCL) to 1850 MPa for the biocomposites produced by using the wet feeding strategy, compared to 690 MPa showed for the biocomposites produced using dry feeling. A wet feeding of acetylated cellulosic fibers allowed even a greater increase, with an additional 46% and 248% increase of the ultimate strength and Young's modulus, when compared to wet feeding of the unmodified pulp, respectively. 

  • 37.
    Mittal, Nitesh
    et al.
    KTH Royal Institute of Tecnology, Sweden.
    Ansari, Farhan
    Stanford University, US; KTH Royal Institute of Tecnology, Sweden.
    Gowda V, Krishne
    KTH Royal Institute of Tecnology, Sweden.
    Brouzet, Christophe
    KTH Royal Institute of Tecnology, Sweden.
    Chen, Pan
    KTH Royal Institute of Tecnology, Sweden.
    Larsson, Per Tomas
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Roth, Stephan V
    KTH Royal Institute of Tecnology, Sweden; Deutsches Elektronen-Synchrotron (DESY), Germany.
    Lundell, Fredrik
    KTH Royal Institute of Tecnology, Sweden.
    Wågberg, Lars
    KTH Royal Institute of Tecnology, Sweden.
    Kotov, Nicholas A
    University of Michigan, US.
    Söderberg, L Daniel
    KTH Royal Institute of Tecnology, Sweden.
    Multiscale Control of Nanocellulose Assembly: Transferring Remarkable Nanoscale Fibril Mechanics to Macroscale Fibers.2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 4, p. 6378-6388Article in journal (Refereed)
    Abstract [en]

    Nanoscale building blocks of many materials exhibit extraordinary mechanical properties due to their defect-free molecular structure. Translation of these high mechanical properties to macroscopic materials represents a difficult materials engineering challenge due to the necessity to organize these building blocks into multiscale patterns and mitigate defects emerging at larger scales. Cellulose nanofibrils (CNFs), the most abundant structural element in living systems, has impressively high strength and stiffness, but natural or artificial cellulose composites are 3-15 times weaker than the CNFs. Here, we report the flow-assisted organization of CNFs into macroscale fibers with nearly perfect unidirectional alignment. Efficient stress transfer from macroscale to individual CNF due to cross-linking and high degree of order enables their Young's modulus to reach up to 86 GPa and a tensile strength of 1.57 GPa, exceeding the mechanical properties of known natural or synthetic biopolymeric materials. The specific strength of our CNF fibers engineered at multiscale also exceeds that of metals, alloys, and glass fibers, enhancing the potential of sustainable lightweight high-performance materials with multiscale self-organization.

  • 38.
    Nowak, Andrzej P.
    et al.
    KTH Royal Institute of Technology, Sweden ; Gdansk university of technology, Poland.
    Hagberg, Johan
    KTH Royal Institute of Technology, Sweden.
    Leijonmarck, Simon
    RISE - Research Institutes of Sweden, Swerea, Swerea KIMAB. KTH Royal Institute of Technology, Sweden.
    Schweinebarth, Hannah
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Baker, Darren A
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Uhlin, Anders
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Tomani, Per
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Lindbergh, Göran
    KTH Royal Institute of Technology, Sweden.
    Lignin-based carbon fibers for renewable and multifunctional lithium-ion battery electrodes2018In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 72, no 2, p. 81-90Article in journal (Refereed)
    Abstract [en]

    Lignin-based carbon fibers (LCFs) from the renewable resource softwood kraft lignin were synthesized via oxidative thermostabilization of pure melt-spun lignin and carbonization at different temperatures from 1000°C to 1700°C. The resulting LCFs were characterized by tensile testing, scanning electron microscopy (SEM), X-ray diffraction (XRD) and confocal Raman spectroscopy. The microstructure is mainly amorphous carbon with some nanocrystalline domains. The strength and stiffness are inversely proportional to the carbonization temperature, while the LCFs carbonized at 1000°C exhibit a strength of 628 MPa and a stiffness of 37 GPa. Furthermore, the application potential of LCFs was evaluated as negative electrodes in a lithium-ion battery (LIB) by electrochemical cycling at different current rates in a half-cell setup. The capacity drops with the carbonization temperature and the LCFs carbonized at 1000°C have a capacity of 335 mAh g-1. All LCFs showed good cycling stability. Because of the mechanical integrity and conductivity of the LCFs, there is no need to apply current collectors, conductive additives or binders. The advantage is an increased gravimetric energy density compared to graphite, which is the most common negative electrode material. LCFs show a promising multifunctional behavior, including good mechanical integrity, conductivity and an ability to intercalate lithium for LIBs.

  • 39.
    Palme, Anna
    et al.
    Chalmers University of Technology, Sweden.
    Peterson, Anna
    Chalmers University of Technology, Sweden.
    de la Motte, Hanna
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Theliander, Hans
    Chalmers University of Technology, Sweden.
    Brelid, Harald
    Södra Innovation, Sweden..
    Development of an efficient route for combined recycling of PET and cotton from mixed fabrics2017In: Textiles and Clothing Sustainability, ISSN 2197-9936, Vol. 3, no 4Article in journal (Refereed)
    Abstract [en]

    Most textile waste is either incinerated or landfilled today, yet, the material could instead be recycled through chemical recycling to new high-quality textiles. A first important step is separation since chemical recycling of textiles requires pure streams. The focus of this paper is on the separation of cotton and PET (poly(ethylene terephthalate), polyester) from mixed textiles, so called polycotton. Polycotton is one of the most common materials in service textiles used in sheets and towels at hospitals and hotels. A straightforward process using 5–15 wt% NaOH in water and temperature in the range between 70 and 90 °C for the hydrolysis of PET was evaluated on the lab-scale. In the process, the PET was degraded to terephthalic acid (TPA) and ethylene glycol (EG). Three product streams were generated from the process. First is the cotton; second, the TPA; and, third, the filtrate containing EG and the process chemicals. The end products and the extent of PET degradation were characterized using light microscopy, UV-spectroscopy, and ATR FT-IR spectroscopy, as well as solution and solid-state NMR spectroscopy. Furthermore, the cotton cellulose degradation was evaluated by analyzing the intrinsic viscosity of the cotton cellulose. The findings show that with the addition of a phase transfer catalyst (benzyltributylammonium chloride (BTBAC)), PET hydrolysis in 10% NaOH solution at 90 °C can be completed within 40 min. Analysis of the degraded PET with NMR spectroscopy showed that no contaminants remained in the recovered TPA, and that the filtrate mainly contained EG and BTBAC (when added). The yield of the cotton cellulose was high, up to 97%, depending on how long the samples were treated. The findings also showed that the separation can be performed without the phase transfer catalyst; however, this requires longer treatment times, which results in more cellulose degradation.

  • 40.
    Peters, Greg
    et al.
    Chalmers University of Technology, Sweden.
    Sandin, Gustav
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Spak, Björn
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Roos, Sandra
    RISE - Research Institutes of Sweden, Swerea, Swerea IVF.
    LCA on fast and slow garment prototypes2018Report (Other academic)
    Abstract [en]

    This report summarises the environmental assessment work done in the Mistra Future Fashion program focussed on the potential to improve the environmental performance of garments and adapt them to a circular economy. The approaches examined in this report include reducing the environmental impacts from fast-fashion trends by making garments from paper-based materials, or by extending garment life cycles.

    This assessment considers two paper-based garments. One is made primarily from paper pulp but enhanced with a polylactic acid polymer. This garment is worn between two to five times before being recycled as newspaper. The other fast garment is made of paper pulp, polylactic acid and nanocellulose. It has a similar life cycle but is composted after use life. These garments are compared with a standard t-shirt. The report also considers a slow-paced scenario in which a polyester garment passes between several owners and is regularly changed to maintain its appeal. It is updated with a transfer sublimation overprint three times, making the garment darker each time. Later it is joined with an outer shell of new material using laser technology to make a cropped, box-cut jacket.

    The assessment was performed using environmental life cycle assessment. More particularly, the assessment was based on attributional process analysis with cutoff allocation procedures and comparison with a traditional reference garment life cycle. Key environmental effect categories considered here include climate change (greenhouse gas emissions), freshwater eutrophication, freshwater ecotoxicity and human toxicity (cancer and non-cancer).

    The results indicate that the environmental outcomes of the paper-based garments can be competitive with the reference garment, particularly when the user is assumed to throw away a fully functional reference garment after five uses. This assumption may be true for some users, but the number of uses is considerably lower than the typical or the potential lifespan of the reference garment. The main factor assisting the paper-based garments is the reduction in the impacts per mass associated with material manufacturing (fibres, spinning, knitting), and also their lighter masses. Avoided impacts in the use phase play a secondary role on account of their location in Sweden with its low-carbon energy mix. The long-life garments are also competitive compared with their reference garments. This is primarily a consequence of how extending garment life avoids the production of new garments. The environmental impacts associated with transfer sublimation dye reprinting and laser processing do not significantly impact the overall environmental performance of the extended longlife garments, though confidentiality of data prevents a full assessment of these.

    The garments in this report are pilot products and explorative scenarios rather than attempts to model existing business or behavioural patterns. The reader should therefore take care to keep the results in context when interpreting them. Nevertheless, the results suggest the value of pursuing the potential associated with these garment life cycles. We should also bear in mind that while the reference garments in this assessment are based on typical usage patterns, other more sustainable patterns are feasible.

  • 41.
    Peters, Greg
    et al.
    Chalmers University of Technology.
    Svanström, Magdalena
    Chalmers University of Technology.
    Roos, Sandra
    RISE - Research Institutes of Sweden, Swerea.
    Sandin, Gustav
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Zamani, Bahareh
    Chalmers University of Technology.
    Carbon footprints in the textile industry: Chapter 12015In: Handbook of Life Cycle Assessment (LCA) of Textiles and Clothing / [ed] Subramanian Muthu, Woodhead Publishing Limited, 2015, 1, p. 3-30Chapter in book (Other academic)
  • 42.
    Pettersson, Karin
    et al.
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy. Chalmers University of Technology, Sweden.
    Lundberg, Valeria
    RISE - Research Institutes of Sweden, Bioeconomy.
    Anheden, Marie
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Fuglesang, Malin
    ÅF Industry, Sweden.
    Systems analysis of different value chains based on domestic forest biomass for the production of bio-SNG2018In: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 42, no 6, p. 2117-2140Article in journal (Refereed)
    Abstract [en]

    This study compares value chains based on domestic forest biomass for the production of bio-synthetic natural gas (SNG) with respect to economic performance, GHG emissions, and energy efficiency. Value chains in which raw material is upgraded to intermediate products before transportation to an SNG plant integrated with a district heating system for further upgrading are compared with a chain in which the raw material is transported directly to the SNG plant. The intermediates considered are either dried biomass from forest residues, or bark, upgraded at pulp mills, or pellets from sawdust upgraded at sawmills. The findings show that the difference in performance between the studied value chains is generally small. The highest cost and significantly lowest energy efficiency are associated with the value chain with pellets, which leads to the conclusion that more pretreatment than what is required by the SNG process, to lower transport costs, is not profitable. Drying forest residues at pulp mills before further transportation to and upgrading at an SNG plant leads to somewhat higher transportation costs because of the relatively high fixed costs associated with transportation. However, the benefit of drying the biomass using excess heat at pulp mills is that heat is "moved" from a location, where it can be hard to find profitable ways to use it, to the SNG plant, where the excess heat can be used for district heating. With these two factors working in opposition, the total cost is similar if forest residues are transported directly to the SNG plant or via a pulp mill. The lowest cost is achieved when falling bark from pulp mills is used because the first transportation step is avoided and no additional investment for biomass handling at the mill is required. However, there is a technical uncertainty regarding how much bark can be used in the SNG process.

  • 43.
    Peñaloza, Diego
    et al.
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy.
    Røyne, Frida
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy.
    Sandin, Gustav
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Svanström, Magdalena
    Chalmers University of Technology, Sweden.
    Erlandsson, Martin
    IVL Swedish Environmental Research Institute, Sweden.
    The influence of system boundaries and baseline in climate impact assessment of forest products2018In: The International Journal of Life Cycle Assessment, ISSN 0948-3349, E-ISSN 1614-7502Article in journal (Refereed)
    Abstract [en]

    Purpose: This article aims to explore how different assumptions about system boundaries and setting of baselines for forest growth affect the outcome of climate impact assessments of forest products using life cycle assessment (LCA), regarding the potential for climate impact mitigation from replacing non-forest benchmarks. This article attempts to explore how several assumptions interact and influence results for different products with different service life lengths. Methods: Four products made from forest biomass were analysed and compared to non-forest benchmarks using dynamic LCA with time horizons between 0 and 300 years. The studied products have different service lives: butanol automotive fuel (0 years), viscose textile fibres (2 years), a cross-laminated timber building structure (50 years) and methanol used to produce short-lived (0 years) and long-lived (20 years) products. Five calculation setups were tested featuring different assumptions about how to account for the carbon uptake during forest growth or regrowth. These assumptions relate to the timing of the uptake (before or after harvest), the spatial system boundaries (national, landscape or single stand) and the land-use baseline (zero baseline or natural regeneration). Results and discussion: The implications of using different assumptions depend on the type of product. The choice of time horizon for dynamic LCA and the timing of forest carbon uptake are important for all products, especially long-lived ones where end-of-life biogenic emissions take place in the relatively distant future. The choice of time horizon is less influential when using landscape- or national-level system boundaries than when using stand-level system boundaries and has greater influence on the results for long-lived products. Short-lived products perform worse than their benchmarks with short time horizons whatever spatial system boundaries are chosen, while long-lived products outperform their benchmarks with all methods tested. The approach and data used to model the forest carbon uptake can significantly influence the outcome of the assessment for all products. Conclusions: The choices of spatial system boundaries, temporal system boundaries and land-use baseline have a large influence on the results, and this influence decreases for longer time horizons. Short-lived products are more sensitive to the choice of time horizon than long-lived products. Recommendations are given for LCA practitioners: to be aware of the influence of method choice when carrying out studies, to use case-specific data (for the forest growth) and to communicate clearly how results can be used.

  • 44.
    Ribul, Miriam
    et al.
    UAL, UK.
    de la Motte, Hanna
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    THE MATERIAL AFFINITY OF DESIGN AND SCIENCE FOR A CIRCULAR ECONOMY2016In: Circular Transitions Proceedings, 2016Conference paper (Refereed)
    Abstract [en]

    This paper presents a design and material science collaboration in a science laboratory for regenerated cellulose. The material affinity outlines how both disciplines are connected through a materials practice in communication and production of cellulose films. The outcome presents new transdisciplinary approaches for design and science towards circularity of materials.

  • 45.
    Rättö, Peter
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Dahlman, Olof
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Junel, Kristina
    RISE - Research Institutes of Sweden, Bioeconomy, Papermaking and Packaging.
    Pilot coating with a hemicellulose-based barrier2018In: PaperCon 2018: Shaping the future through innovation, TAPPI , 2018, article id FF1.3Conference paper (Refereed)
    Abstract [en]

    A hemicellulose-based barrier formulation was produced from wood chips to pilot coating application in a bladecoater. The development process is described from a project planning point of view with network plan and decisionpoints.Different hemicelluloses were produced and compared in the research laboratory. Oxygen barrier properties fromfilms and rheology of water suspensions were evaluated for different laboratory produced hemicelluloses originatingfrom wood chips or from kraft pulps. The viscosity at low and high shear rates were evaluated. From these results,hemicellulose produced from birch wood chips was chosen.Hemicellulose was then produced at in kg quantities. The hemicellulose was produced employing pre-hydrolysistreatment of birch wood chips. The concentration of hemicellulose pre-hydrolyses was increased from 3.3% to11.5% by membrane filtration. The barrier properties of the hemicellulose coated material were evaluated inlaboratory scale. A pre-coating was also evaluated in laboratory scale.Trials were performed at Iggesund PaperBoard in their pilot scale coater. A pre-coating was applied during the firstday, and the hemicellulose-based coating was applied on the second day. The pilot trials went well without anylarger obstacles. Quick barrier evaluations showed that the hemicellulose-based barrier coating had a good greaseresistance even if the coating consumption during the trials indicated a low application grammage.

  • 46.
    Rönnols, Jerk
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    Jacobs, Anna
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    Aldaeus, Fredrik
    RISE - Research Institutes of Sweden, Bioeconomy, Biobased Materials.
    Larsson, Tomas
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Digging in the structure and functionality of lignocellulosic raw material: from academic knowledge towards industrial applications2018In: The 8th Nordic Wood Biorefinery Conference: NWBC 2018 : proceedings / [ed] Hytönen Eemeli, Vepsäläinen Jessica, Espoo: VTT , 2018, p. 205-205Conference paper (Other academic)
  • 47.
    Røyne, Frida
    et al.
    RISE - Research Institutes of Sweden, Built Environment. Umeå University, Umeå, Sweden.
    Peñaloza, Diego
    RISE - Research Institutes of Sweden, Built Environment. KTH, Stockholm, Sweden.
    Sandin, Gustav
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Berlin, Johanna
    RISE - Research Institutes of Sweden, Built Environment.
    Svanström, Magdalena
    Chalmers University of Technology, Gothenburg, Sweden.
    Climate impact assessment in life cycle assessments of forest products: Implications of method choice for results and decision-making2016In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 116, p. 90-99Article in journal (Refereed)
    Abstract [en]

    As life cycle assessments are often conducted to provide decision support, it is important that impact assessment methodology is consistent with the intended decision context. The currently most used climate impact assessment metric, the global warming potential, and how it is applied in life cycle assessments, has for example been criticised for insufficiently accounting for carbon sequestration, carbon stored in long-lived products and timing of emission. The aim of this study is to evaluate how practitioners assess the climate impact of forest products and the implications of method choice for results and decision-making.

    To identify current common practices, we reviewed climate impact assessment practices in 101 life cycle assessments of forest products. We then applied identified common practices in case studies comparing the climate impact of a forest-based and a non-forest-based fuel and building, respectively, and compared the outcomes with outcomes of applying alternative, non-established practices.

    Results indicate that current common practices exclude most of the dynamic features of carbon uptake and storage as well as the climate impact from indirect land use change, aerosols and changed albedo. The case studies demonstrate that the inclusion of such aspects could influence results considerably, both positively and negatively. Ignoring aspects could thus have important implications for the decision support. The product life cycle stages with greatest climate impact reduction potential might not be identified, product comparisons might favour the less preferable product and policy instruments might support the development and use of inefficient climate impact reduction strategies.

  • 48.
    Salmen, Lennart
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Wood cell wall structure and organisation in relation to mechanics2018In: Plant Biomechanics: From structure to function at multiple scales, Springer International Publishing , 2018, p. 3-19Chapter in book (Other academic)
    Abstract [en]

    The wood cell wall, as well as the entire wood structure, is a highly intermixed assembly of biopolymers building up various structural elements. The understanding of the organisation of these wood polymers and their interaction is a key to be able to better utilise wood materials. The complexity of the wood cell wall is here discussed regarding the cellulose fibrillar network, the cellulose aggregate structure and the arrangement of the matrix polymers of hemicelluloses and lignin. The ability to model the wood cell wall properties, based on the structural organisation within different cell wall structures, and the difficulties in relating predictions to actual measurements of cell wall properties are described. The deficiencies regarding our structural knowledge in relation to mechanical properties are also being defined.

  • 49.
    Salmen, Lennart
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Larsson, Per A
    KTH Royal Institute of Technology, Sweden.
    On the origin of sorption hysteresis in cellulosic materials2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 182, p. 15-20Article in journal (Refereed)
    Abstract [en]

    Moisture sorption and moisture sorption hysteresis of carbohydrates are phenomena which affect the utilisation of products made thereof. Although extensively studied, there is still no consensus regarding the mechanisms behind sorption hysteresis. Attempts have been made to link the behaviour to molecular properties, in particular to softening properties, and the moisture sorption hysteresis has therefore here been investigated by modifying cellulosic fibres to affect their softening properties. The results show that the moisture sorption hysteresis diminishes with decreasing softening temperature, and was even completely absent at the higher degrees of modification. The moisture sorption characteristics also changed from a type II sorption to a more type III sorption behaviour, a feature more prominent the higher the degree of modification and the higher the temperature. For the highest degree of modification studied the sorption characteristics changed from sorbing less water the higher the temperature to sorbing more water with increasing temperature.

  • 50.
    Salmen, Lennart
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Stevanic Srndovic, Jasna
    Effect of drying conditions on cellulose microfibril aggregation and "€œhornification"2018In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, no 11, p. 6333-6344Article in journal (Refereed)
    Abstract [en]

    Drying of chemical pulps results in a decreased swelling of the fibres, leading to lower density and strength properties of paper sheets. To investigate how variation of pulp pH, drying process temperature, and final moisture content affect this phenomenon, structural studies were performed on a cellulose-rich pulp. Interrupting the drying at moisture contents of around 20%, using drying temperatures of 80 °C and 140 °C, resulted in a more severe degree of hornification than if the pulp was completely dried at the same temperatures. This increased loss of swelling was accompanied by increased cellulose microfibril aggregation. No change of the cellulose microfibril size or of the cellulose crystallinity, as determined by NMR, could be seen. Further, the accessibility of the cellulose microfibril surfaces, including surfaces between microfibrils, was unaffected by the drying. Thus, hornification should not primarily be related to a reduction of accessible cellulosic surfaces.

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