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  • 1.
    Afewerki, Samson
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Breistein, Palle
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Pirttilä, Kristian
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Deiana, Luca
    Univ Stockholm, Arrhenius Lab, Dept Organ Chem, S-10691 Stockholm, Sweden.
    Dziedzic, Pawel
    Univ Stockholm, Arrhenius Lab, Dept Organ Chem, S-10691 Stockholm, Sweden.
    Ibrahem, Ismail
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Córdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Catalytic Enantioselective beta-Alkylation of alpha,beta-Unsaturated Aldehydes by Combination of Transition-Metal- and Aminocatalysis: Total Synthesis of Bisabolane Sesquiterpenes2011In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 17, no 32, 8784-8788 p.Article in journal (Refereed)
    Abstract [en]

    Branching out! The first co-catalytic enantioselective (up to 98:2 e.r.) β-alkylation of α,β-unsaturated aldehydes by combination of simple chiral amine and copper catalysts provides β-branched aldehydes in a one-pot protocol (see scheme). The methodology was applied to the short total syntheses of bisabolane sesquiterpenes (S)-(+)-curcumene, (E)-(S)-(+)-3- dehydrocurcumene and (S)-(+)-tumerone. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • 2.
    Ali, Tara
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Bylund, Dan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Essén, Sofia A.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Lundström, Ulla
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Liquid extraction of low molecular mass organic acids and hydroxamate siderophores from boreal forest soil2011In: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 43, no 12, 2417-2422 p.Article in journal (Refereed)
    Abstract [en]

    Low molecular mass organic acids (LMMOAs) and hydroxamate siderophores (HS) are molecules secreted by microbes and have previously been found in soil solution and in cultures. Mycorrhizal fungi are suggested to be involved in the nutrient uptake processes of trees and weathering of minerals. In this study soil samples taken from the O and E horizons of a podzol were extracted with 10 mM potassium phosphate buffer at pH 7.2. Variable parameters included addition of methanol to the extraction buffer and the use of ultrasonication or rotary shaking during extraction. LMMOAs and HS content of the soil extracts were determined. Analysis of soil extracts were carried out by liquid chromatography mass spectrometry (LC-MS) and the extraction results compared to results for soil solution samples obtained by centrifugation of the soils sampled. The extraction yields were significantly increased by addition of methanol to the extraction buffer, especially for the O horizon samples. Rotary shaking of the samples for 90 min gave slightly higher yields than ultrasonication for 15 min but the reduction in extraction time makes ultrasonication an attractive option. Of the HSs determined, ferricrocin was found in all samples. Optimal extraction conditions showed citric acid and isocitric acid to be the most abundant organic acids in the O and E horizons, respectively.

  • 3. Alison, M Lee-Manion
    et al.
    Price, Ruth K
    Strain, J J
    Dimberg, Lena H
    Sunnerheim, Kerstin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Welch, Robert W
    In Vitro Antioxidant Activity and Antigenotoxic Effects of Avenanthramides and Related Compounds2009In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 57, no 22, 10619-10624 p.Article in journal (Refereed)
    Abstract [en]

    Avenanthramides are substituted N-cinnamoylanthranilic acids, with hydroxycinnamic acid and anthranilic acid moieties. These alkaloid phenols, which are unique to oats, may confer health benefits via antioxidant or other mechanisms. Synthetic avenanthramides, hydroxycinnamic acids, Tranilast, and ascorbic acid were evaluated for antioxidant activity using two assays, DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing antioxidant potential), and for antigenotoxicity using the Comet assay with stressed human adenocarcinoma colon cells. Of all the compounds tested, N-(3′,4′-dihydroxy-(E)-cinnamoyl)-5-hydroxyanthranilic acid (2c), an abundant oat avenanthramide, generally had the highest activity in all three assays. The drug Tranilast showed antigenotoxic effects, but not antioxidant activity, suggesting that antigenotoxicity is not dependent on antioxidant effects. Overall, results show that avenanthramides exert antioxidant and antigenotoxic activities that are comparable to those of ascorbic acid and which have the potential to exert beneficial physiological effects.

     

  • 4.
    Altomani, Andrea
    et al.
    Université du Luxembourg.
    Hill, C. Denson
    SUNY Stony Brook, New York.
    Nacinovich, Mauro
    Universitá Roma Tor Vergata.
    Porten, Egmont
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Complex vector fields and hypolleptic partial differential operators2010In: Annales de l'Institut Fourier, ISSN 0373-0956, E-ISSN 1777-5310, Vol. 60, no 3, 39 p.987-1034 p.Article in journal (Refereed)
    Abstract [en]

    We prove a subelliptic estimate for systems of complex vector fields under some assumptions that generalize the essential pseudoconcavity for CR manifolds, that was first introduced by two of the authors; and the Hormander's bracket condition for real vector fields. Applications are given to prove the hypoellipticity of first order systems and second order partial differential operators. Finally we describe a class of compact homogeneous CR manifolds for which the distribution of (0,1) vector fields satisfies a subelliptic estimate.

  • 5. Altomani, Andrea
    et al.
    Hill, C. Denson
    Nacinovich, Mauro
    Porten, Egmont
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Holomorphic Extension from Weakly Pseudoconcave CR Manifolds2010In: Rendiconti del Seminario Matematico della Universita di Padova, ISSN 0041-8994, E-ISSN 2240-2926, Vol. 123, 69-90 p.Article in journal (Refereed)
    Abstract [en]

    Let M be a smooth locally embeddable CR manifold, having some CR dimension M and some CR codimension d. We find an improved local geometric condition on M which guarantees, at a point p on M, that germs of CR distributions are smooth functions, and have extensions to germs of holomorphic functions on a full ambient neighborhood of p. Our condition is a form of weak pseudoconcavity, closely related to essential pseudoconcavity as introduced in [HN1]. Applications are made to CR meromorphic functions and mappings. Explicit examples are given which satisfy our new condition, but which are not pseudoconcave in the strong sense. These results demonstrate that for codimension d > 1 there are additional phenomena, which are invisible when d = 1.

  • 6. Anderbrant, Olle
    et al.
    Lyons, D. Barry
    Bång, Joakim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Sex Pheromone of the Introduced Pine Sawfly, Diprion similis (Diprionidae), Revisited: No Activity of Earlier Reported SynergistsManuscript (preprint) (Other academic)
    Abstract [en]

    Extracts of Diprion similis females were found to contain about 15 ng of the sex pheromone precursor 3,7-dimethylpentadecan-2-ol per female. When analysing the extracts after derivatisation with (2S)-2-acetoxypropionyl chloride, we found that the major stereoisomer in the extract was (2S,3R,7R)-3,7-dimethylpentadecan-2-ol. Also other stereoisomers of 3,7-dimethylpentadecan-2-ol were identified in the extract namely, 1% of (2R,3S,7S) , 0.3% (2R,3R,7R) and 0.4% of (2R,3R,7S). An unknown fifth substance showed an identical spectrum to 3,7-dimethylpentadecan-2-ol, both in SIM and full scan mode. In field tests in Ontario, Canada, the earlier identified main pheromone component, viz. the propanoate of (2S,3R,7R)-3,7-dimethylpentadecan-2-ol, was tested alone and in combination with other stereoisomers, earlier reported to be synergistic. In none of the tests were any synergistic effects detected and the threo four-isomer blend was as attractive as the pure main compound. Thus, one of the few examples of a diprionid sawfly using more than one substance in its sex pheromone could not be confirmed. The results also suggest that monitoring programs can use the more easily synthesized threo-blend without losing efficiency.

  • 7.
    Anderbrant, Olle
    et al.
    Department of Biology, Lund University.
    Löfqvist, Jan
    Department of Plant Protection Science, Swedish University of Agricultural Sciences, Alnarp.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Bång, Joakim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Tai, Akira
    Faculty of Science, Himeji Institute of Technology, Kanaji Kamigor, Japan.
    Högberg, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Field Response of Male Pine Sawflies, Neodiprion sertifer (Diprionidae), to Sex Pheromone Analogs in Japan and Sweden2010In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 36, no 9, 969-977 p.Article in journal (Refereed)
    Abstract [en]

    The pine sawfly Neodiprion sertifer (Geoffroy) uses the acetate or propionate of (2S,3S,7S)-3,7-dimethyl-2-pentadecanol (diprionol) as pheromone components, with the (2S,3R,7R)-isomer being antagonistic, synergistic, or inactive according to the population tested. In this study, we tested the attraction of males to the acetates of three analogs of diprionol, each missing one methyl group, viz. (2S,7S)-7-methyl-2-pentadecanol, (2S,6S)-2,6-dimethyl-1-tetradecanol, and (2S,3S)-3-methyl-2-pentadecanol. None of the analogs alone, or in combination with diprionol acetate, was attractive in Sweden, even at 100 times the amount of diprionol acetate attractive to N. sertifer. In Japan, the acetate of (2S,3S)-3-methyl-2-pentadecanol attracted males when tested in amounts 10–20 times higher than the acetate pheromone component. The acetate esters of the (2S,3R)-analog and the (2S,3R,7R)-isomer of diprionol also were tested in combination with the pheromone compound (acetate ester). Both compounds caused an almost total trap-catch reduction in Sweden, whereas in Japan they appear to have relatively little effect on trap capture when added to diprionol acetate. Butyrate and iso-butyrate esters of diprionol were unattractive to N. sertifer in Sweden. In summary, there exists geographic variation in N. sertifer in responses to both diprionyl acetate and some of its analogs.

  • 8.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Öhlund, Thomas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Manuilskiy, Anatoliy
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Forsberg, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Örtegren, Jonas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Evaluation of InkAid surface treatment to enhance print quality of ANP silver nano-particle ink on plastic substrates2010In: Large Area, Organic & Printed Electronics (LOPE-C) 2010, Frankfurt, 2010, 241-245 p.Conference paper (Refereed)
  • 9.
    Andersson, J
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Wågberg, Lars
    KTHB.
    Ageing of Flexographic Printed Model Cellulose Surfaces and Determination of the Mechanisms Behind Ageing2009In: Pulp & paper Canada, ISSN 0316-4004, Vol. 110, no 7-8, 34-38 p.Article in journal (Refereed)
    Abstract [en]

    The influence of storage conditions on the ink detachment efficiency of

    water-based flexographic ink printed onto model cellulose surfaces and

    handsheets was investigated. It was shown that UV light, elevated

    temperatures, longer storage time, increasing surface roughness, and

    increasing surface hydrophobicity all had a negative effect on ink

    detachment. It was also shown that the ink's chemical and structural

    characteristics changed when stored at elevated temperatures. No

    chemical or structural changes could be observed for the ink when

    stored under UV light.

     

  • 10.
    Andersson, Kerstin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Lignin in wastewater generated by mechalical pulping: Chemical characterisation and removal by adsorption2010Licentiate thesis, comprehensive summary (Other academic)
  • 11.
    Andersson, Kerstin I
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Eriksson, Marie
    SCA R&D Ctr, SE-85121 Sundsvall, Sweden.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Removal of Lignin from Wastewater Generated by Mechanical Pulping Using Activated Charcoal and Fly Ash: Adsorption Isotherms and Thermodynamics2011In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 50, no 13, 7722-7732 p.Article in journal (Refereed)
    Abstract [en]

    Lignin-related material found in wastewater from thermomechanical pulping resists conventional biological treatment, entailing the use of advanced removal methods. In this work, the use of adsorption for removing lignin-related material was investigated. Activated charcoal and fly ash were used to study the adsorption behavior of lignin and to determine the adsorption capacities of these two adsorbents. Experimental data were fitted to various isotherm equations to find the best description of the sorption systems, and the corresponding thermodynamic parameters were calculated. Fly ash exhibited good sorption properties, although its sorption capacity was inferior to that of activated charcoal. Both the Freundlich and Langmuir equations provided reasonable models of the sorption processes, and the thermodynamic parameters indicated that sorption onto activated charcoal is endothermic, whereas sorption onto fly ash appears to be exothermic. Fly ash is a low-cost material that is often available on-site and offers an interesting alternative to high-cost advanced wastewater treatment systems for removing recalcitrant organic materials.

  • 12.
    Andersson, Kerstin I.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Eriksson, Marie
    SCA R&D Ctr, SE-85121 Sundsvall, Sweden.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Removal of Lignin from Wastewater Generated by Mechanical Pulping Using Activated Charcoal and Fly Ash: Adsorption Kinetics2011In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 50, no 13, 7733-7739 p.Article in journal (Refereed)
    Abstract [en]

    The possible application of adsorption for the removal of lignin-related material found in wastewater generated by mechanical pulping was investigated. Activated charcoal and fly ash were used as adsorbents in batch experiments. The lignin-related material exhibited properties well-suited for adsorption onto both adsorbents, although the sorption capacity of activated charcoal exceeds that of fly ash. The experimental data were fitted to pseudo-first- and pseudo-second-order rate kinetic expressions, and an attempt was made to find the rate-limiting step involved in the adsorption processes. The results showed that lignin adsorption onto both activated charcoal and fly ash follows pseudo-second-order rate kinetics and that both boundary-layer diffusion and intraparticle diffusion are likely involved in the rate-limiting mechanisms. Adsorption is an interesting option in advanced wastewater treatment, and fly ash appears to be a suitable low-cost adsorbent for recalcitrant organic pollutants.

  • 13.
    Andersson, Kerstin I
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Eriksson, Magnus
    SCA R and D Centre, Sundsvall, Sweden.
    Lignin removal from wastewater by adsorption2009In: Proceedings - 2009 International Mechanical Pulping Conference, IMPC 2009, 2009, 280-285 p.Conference paper (Refereed)
    Abstract [en]

    Lignin contributes to residual COD in wastewater after biological treatment. Available methods for removal of recalcitrant material like lignin, e.g. chemical oxidation and coagulation, are associated with heavy operational expenses. Stringent discharge requirements demand new cost-effective methods for removal of recalcitrant COD. Adsorption is an important mechanism for lignin removal in biological wastewater treatment. A study of lignin, using activated carbon as a model adsorbent, was performed to learn more about the adsorption behaviour of lignin. At the adsorbent dose 4 g/L and an initial lignin concentration of 0.5 g/L, 77% of the lignin was removed after six hours. The adsorption kinetics was found to follow the pseudo second-order rate expression and no temperature dependency could be observed in the temperature range studied.

     

     

  • 14.
    Andersson, Kerstin
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Pranovich, Andrey
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Eriksson, Marie
    Holmbom, Bjarne
    Effects of biological treatment on the chemical structure of dissolved lignin-related substances in effluent from thermomechanical pulping2008In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, Vol. 23, no 2, 164-171 p.Article in journal (Refereed)
    Abstract [en]

    Effluent from a TMP-based pulp and paper mill was collected at the inlet and outlet of the mill's biological treatment plant and fractionated by sorption on XAD-8 resin and MTBE precipitation. Fractionation indicated that the refractory dissolved organic material in biologically treated effluent was mainly composed of lignin-related substances. Characterisation of the lignin-related substances by chromatographic and spectrometric methods confirmed the similarities of the isolated material and milled wood lignin. Fractionation and characterisation of alkali-extracted material from solids (biosludge) in biologically treated effluent found evidence of lignin-related material. Results indicated that biological treatment had altered the chemical structure and molar-mass distribution of dissolved lignin-related substances.

  • 15.
    Andersson, Stefan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Low consistency refining of mechanical pulp: process conditions and energy efficiency2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The thesis is focussed on low consistency (LC) refining of mechanical pulp. Theresearch included evaluations of energy efficiency, development of pulpproperties, the influence of fibre concentration on LC refining and effects of rotorposition in a two-zoned LC refiner.

    Trials were made in mill scale in a modern TMP line equipped with an MSDImpressafiner for chip pre-treatment, double disc (DD) first stage refining and aprototype 72-inch TwinFlo LC refiner in the second stage. Tensile index increasedby 8 Nm/g and fibre length was reduced by 10 % in LC refining at 140 kWh/adtgross specific refining energy and specific edge load 1.0 J/m. Specific lightscattering coefficient did not develop significantly over the LC refiner.

    The above mentioned TMP line was compared with a two stage single disc highconsistency Twin 60 refiner line. The purpose was to evaluate specific energyconsumption and pulp properties. The two different process solutions were testedin mill scale, running similar Norway spruce wood supply. At the same tensileindex and freeness, the specific energy consumption was 400 kWh/adt lower in theDD-LC concept compared with the SD-SD system. Pulp characteristics of the tworefining concepts were compared at tensile index 47 Nm/g. Fibre length was lowerafter DD-LC refining than after SD-SD refining. Specific light scattering coefficientwas higher and shive content much lower for DD-LC pulp.

    The effects of sulphite chip pre-treatment on second stage LC refining were alsoevaluated. No apparent differences in fibre properties after LC refining werenoticed between treated and untreated pulps. Sulphite chip pre-treatment iniiicombination with LC refining in second stage, yielded a pulp without screeningand reject refining with tensile index and shives content that were similar to nonpre-treated final pulp after screening and reject refining.

    A pilot scale study was performed to investigate the influence of fibreconcentration on pulp properties in LC refining of mechanical pulps. MarketCTMP was utilised in all trials and fibre concentrations were controlled by meansof adjustments of the pulp consistency and by screen fractionation of the pulp. Inaddition, various refiner parameters were studied, such as no-load, gap and baredge length. Pulp with the highest fibre concentration supported a larger refinergap than pulp with low fibre concentration at a given gross power input. Fibreshortening was lower and tensile index increase was higher for long fibre enrichedpulp. The results from this study support the interesting concept of combiningmain line LC refining and screening, where screen reject is recycled to the LCrefiner inlet.

    It has been observed that the rotor in two-zoned refiners is not always centred,even though pulp flow rate is equal in both refining zones. This leads to unequalplate gaps, which renders unevenly refined pulp. Trials were performed in millscale, using the 72-inch TwinFlo, to investigate differences in pulp properties androtor positions by means of altering the pressure difference between the refiningzones. In order to produce homogenous pulp, it was found that uneven plate gapscan be compensated for in LC refiners with dual refining zones. Results from thedifferent flow rate adjustments indicated that the control setting with similar plategap gave the most homogenous pulp.

  • 16.
    Andersson, Stefan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Sandberg, Christer
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Effect of fibre length distribution on low consistency refining of mechanical pulpManuscript (preprint) (Other academic)
  • 17.
    Andersson, Stefan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Sandberg, Christer
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    The effect of rotor position on pulp properties in a two-zoned low consistency refiner2012In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, no 3, 525-530 p.Article in journal (Refereed)
    Abstract [en]

    Earlier studies have shown that plate gaps are sometimes unequal in two-zoned low consistency refiners and that unequal gaps render unevenly refined pulp. It is also known that optimisation of plate gap in low consistency refining leads to improved energy efficiency. In this work, trials were made in mill scale in a modern TMP line equipped with a prototype 72 inch TwinFlo low consistency refiner in second stage. The study was designed to investigate the development of pulp properties from different rotor positions by means of altering the outlet flow rate ratio. The specific energy consumption was calculated for each refining zone and setting, based on flow rate and temperature increase. In order to produce homogenous pulp, it was found that uneven plate gaps need to be compensated in low consistency refiners with dual refining zones. Results from the different flow rate adjustments indicated that the control setting with similar plate gap gave the most homogenous pulp. However, further studies are needed to find an adequate rotor control strategy. The temperature increase in each refining zone seems to correlate well with the applied specific energy consumption in each refining zone.

  • 18.
    Angelstam, Per
    et al.
    Swedish Univ Agr Sci, Sch Forest Management, Fac Forest Sci, Skinnskatteberg, Sweden.
    Andersson, Kjell
    Swedish Univ Agr Sci, Sch Forest Management, Fac Forest Sci, Skinnskatteberg, Sweden.
    Axelsson, Robert
    Swedish Univ Agr Sci, Sch Forest Management, Fac Forest Sci, Skinnskatteberg, Sweden.
    Elbakidze, Marine
    Swedish Univ Agr Sci, Sch Forest Management, Fac Forest Sci, Skinnskatteberg, Sweden.
    Jonsson, Bengt Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Roberge, Jean-Michel
    Swedish Univ Agr Sci, Dept Wildlife Fish & Environm Studies, Fac Forest Sci, S-90183 Umeå, Sweden.
    Protecting Forest Areas for Biodiversity in Sweden 1991-2010: the Policy Implementation Process and Outcomes on the Ground2011In: Silva Fennica, ISSN 0037-5330, Vol. 45, no 5, 1111-1133 p.Article in journal (Refereed)
    Abstract [en]

    Swedish forest and environmental policies imply that forests should be managed so that all naturally occurring species are maintained in viable populations. This requires maintenance of functional networks of representative natural forest and cultural woodland habitats. We first review the policy implementation process regarding protected areas in Sweden 1991-2010, how ecological knowledge was used to formulate interim short-term and strategic long-term biodiversity conservation goals, and the development of a hierarchical spatial planning approach. Second, we present data about the amount of formally protected and voluntarily set aside forest stands, and evaluate how much remains in terms of additional forest protection, conservation management and habitat restoration to achieve forest and environmental policy objectives in the long-term. Third, a case study in central Sweden was made to estimate the functionality of old Scots pine, Norway spruce and deciduous forest habitats, as well as cultural woodland, in different forest regions. Finally, we assess operational biodiversity conservation planning processes. We conclude that Swedish policy pronouncements capture the contemporary knowledge about biodiversity and conservation planning well. However, the existing area of protected and set-aside forests is presently too small and with too poor connectivity. To bridge this gap, spatial planning, management and restoration of habitat, as well as collaboration among forestand conservation planners need to be improved.

  • 19.
    Angelstam, Per
    et al.
    Sveriges Lantbruksuniversitet.
    Jonsson, Bengt Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Törnblom, Johan
    Sveriges Lantbruksuniversitet.
    Andersson, K
    Sveriges Lantbruksuniversitet.
    Axelsson, Robert
    Sveriges Lantbruksuniversitet.
    Roberge, Jean-Michel
    Sveriges Lantbruksuniversitet.
    Landskapsansats för bevarande av skoglig biologisk mångfald: en uppföljning av 1997 års regionala bristanalys, och om behovet av samverkan mellan aktörer2010Report (Other academic)
  • 20.
    Angelstam, Per
    et al.
    Sveriges Lantbruksuniversitet.
    Roberge, Jean-Michel
    Sveriges Lantbruksuniversitet.
    Jonsson, Bengt-Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Törnblom, Johan
    Sveriges Lantbruksuniversitet.
    Hur mycket är nog för att bevara arterna?2010In: Fakta Skog, ISSN 1400-7789, no 12, 1-4 p.Article, review/survey (Other academic)
  • 21.
    Aronsson, K. Andreas
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Ekelund, Nils
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Limnological effects on a first order stream after Wood Ash Application to a boreal forest catchment in Bispgården, Sweden2008In: Forest Ecology and Management, ISSN 0378-1127, Vol. 255, no 1, 245-253 p.Article in journal (Refereed)
    Abstract [en]

    In Sweden, whole tree harvest is common practice, possibly leading to the depletion of mineral nutrients. Furthermore, the increased use of forestry residues for heat production has caused an increasingly growing amount of by-product consisting of wood ash. Therefore, the Swedish Forest Agency has recommended wood ash application (WAA) to replace the mineral nutrients removed by whole tree harvesting, as well as a means to mitigate the acidification of boreal forests and surface waters. In a multidisciplinary study during 2003-2006 in Bispgarden (Sweden), we have investigated the limnological effects on a first order stream after WAA (conducted in 2004; 3000 kg ha-1) to a 50-ha forested catchment. In general, no significant effects on an annual basis were found for acidification parameters, such as pH, alkalinity and toxic forms of aluminum (Al). There was, however, evidence of an increased pH during the spring flood, accompanied by a simultaneous decrease in the frequency of low pH-values (<5.6). Moreover, alkalinity increased in the years 2005 and 2006 compared to that of 2003, although the increase in 2006 was not statistically different from that in 2005 or 2003. High concentrations of Al repeatedly occurred in the stream, and the WAA did not affect the frequencies of high concentrations of toxic Al forms (>50 μg 1-1). The benthic diatom community did not change as a result of the wood ash treatment and the diatom-based index IPS (Indice de PulluoSensibilité) indicated no nutrient enrichment or organic pollution of the stream water. There were, however, indices of elevated concentrations of potassium (K) in the aquatic moss Fontinalis antipyretica and in leaves from Alder (Alnus incana). We conclude that wood ash treatment of a forested catchment with the dose and form of ash applied in this study did not modify the freshwater ecosystem of a first order stream.

  • 22. Barsoum, N
    et al.
    Nilsson, Christer
    Holm, Svante
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Lakes as potential barriers to gene flow in the hydrochorus plant species Angelica archangelica L. subsp. archangelicaManuscript (Other academic)
  • 23.
    Berg, Jan-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Wood and fibre mechanics related to the thermomechanical pulping process2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The main objective of this thesis was to improve the understanding of some aspects on wood and fibre mechanics related to conditions in the thermomechanical pulping process. Another objective was to measure the power distribution between the rotating plates in a refiner.

     

    The thesis comprises the following parts:

    –A literature review aimed at describing fracture in wood and fibres as related to the thermomechanical pulping process

    –An experimental study of fracture in wood under compression, at conditions similar to those in feeding of chips into preheaters and chip refiners

    –An experimental study of the effect of impact velocity on the fracture of wood, related to conditions of fibre separation in the breaker bar zone in a chip refiner

    –A micromechanical model of the deterioration of wood fibres, related to the development of fibre properties during the intense treatment in the small gap in the refining zone

    –Measurements of the power distribution in a refiner.

     

    The fracture in wood under compression was investigated by use of acoustic emission monitoring. The wood was compressed in both lateral and longitudinal directions to predict preferred modes of deformation in order to achieve desired irreversible changes in the wood structure. It was concluded that the most efficient compression direction in this respect is longitudinal. Preferable temperature at which the compression should be carried out and specific energy input needed in order to achieve substantial changes in the wood structure were also given.

     

    The fibre separation step and specifically the effect of impact velocity on the fracture energy were studied by use of a falling weight impact tester. The fracture surfaces were also examined under a microscope. An increase in impact velocity resulted in an increase in fracture energy.

    In the thermomechanical pulping process the fibres are subjected to lateral compression, tension and shear which causes the creation of microcracks in the fibre wall. This damage reduces the fibre wall stiffness. A simplified analytical model is presented for the prediction of the stiffness degradation due to the damage state in a wood fibre, loaded in uni-axial tension or shear. The model was based on an assumed displacement field together with the minimum total potential energy theorem. For the damage development an energy criterion was employed. The model was applied to calculate the relevant stiffness coefficients as a function of the damage state. The energy consumption in order to achieve a certain damage state in a softwood fibre by uniaxial tension or shear load was also calculated. The energy consumption was found to be dependent on the microfibril angle in the middle secondary wall, the loading case, the thicknesses of the fibre cell wall layers, and conditions such as moisture content and temperature. At conditions, prevailing at the entrance of the gap between the plates in a refiner and at relative high damage states, more energy was needed to create cracks at higher microfibril angles. The energy consumption was lower for earlywood compared to latewood fibres. For low microfibril angles, the energy consumption was lower for loading in shear compared to tension for both earlywood and latewood fibres. Material parameters, such as initial damage state and specific fracture energy, were determined by fitting of input parameters to experimental data.

    Only a part of the electrical energy demand in the thermomechanical pulping process is considered to be effective in fibre separation and developing fibre properties. Therefore it is important to improve the understanding of how this energy is distributed along the refining zone.

    Investigations have been carried out in a laboratory single-disc refiner. It was found that a new developed force sensor is an effective way of measuring the power distribution within the refining zone. The collected data show that the tangential force per area and consequently also the power per unit area increased with radial position.

    The results in this thesis improve the understanding of the influence of some process parameters in thermomechanical pulping related wood and fibre mechanics such as loading rate, loading direction, moisture content and temperature to separate the fibres from the wood and to achieve desired irreversible changes in the fibre structure. Further, the thesis gives an insight of the spatial energy distribution in a refiner during thermomechanical pulping.

     

     

  • 24.
    Berg, Jan-Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Gradin, Per A
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Fibre wall crack development2009In: Proceedings - 2009 International Mechanical Pulping Conference, IMPC 2009, 2009, 340-343 p.Conference paper (Refereed)
    Abstract [en]

    An analytical model has been applied to calculate the energy to achieve a certain damage state in a softwood fibre wall by uniaxial tension or shear load. At conditions such as prevailing at the entrance of the gap between the plates in a refiner less energy was needed for earlywood compared to latewood fibres. The energy was lower for loading in shear compared to tension for both earlywood and latewood fibres with a low microfibril angle. This implies that it would be preferred to refine earlywood and latewood fibres separately.

  • 25.
    Berg, Jan-Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Gulliksson, Mårten E.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Gradin, Per A.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    On the energy consumption for crack development in fibre wall in disc refining - A micromechanical approach2009In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 63, no 2, 204-210 p.Article in journal (Refereed)
    Abstract [en]

    An analytical model has been applied to calculate the acquired strain energy density in order to achieve a certain damage state in a softwood fibre by uniaxial tension or shear load. The energy density was found to be dependent on the microfibril angle in the middle secondary wall, the loading case, the thicknesses of the fibre cell wall layers, and conditions such as moisture content and temperature. At conditions, prevailing at the entrance of the gap between the plates in a refiner and at relative high damage states, more energy is needed to create cracks at higher microfibril angles. The energy density was lower for earlywood compared to latewood fibres. For low microfibril angles, the energy density was lower for loading in shear compared to tension for both earlywood and latewood fibres. Material parameters, such as initial damage state and specific fracture energy, were determined by fitting of input parameters to experimental data.

  • 26.
    Berglund, Håkan
    et al.
    Dept of Ecology, SLU, Uppsala.
    Jonsson, Bengt Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Assessing the extinction vulnerability of wood-inhabiting fungal species in fragmented northern Swedish boreal forests2008In: Biological Conservation, ISSN 0006-3207, E-ISSN 1873-2917, Vol. 141, no 12, 3029-3039 p.Article in journal (Refereed)
    Abstract [en]

    Fragmentation of old-growth forests and greatly reduced amounts of coarse dead wood in managed forests threat the persistence of many saproxylic species in boreal Fennoscandia. Individual old-growth forest remnants may lose species over time as they pay off their extinction debt. We tested this by comparing the observed site occupancy of individual wood-inhabiting fungal species in isolated old-growth stands (i.e. woodland key habitats; WKHs) with statistical predictions of their occupancy assuming potential extinction debt had already been paid off. The occupancy of species was analysed in two sets of WKHs differing in time since isolation (i.e. recent and old isolates).

    Few species occurred more frequently than expected in WKHs. However, patterns across species and across all WKHs masked important differences among species in their risk of facing future extinction. The site occupancy decreased significantly between recent and old isolates for a group of annual, red-listed specialist fungal species, suggesting that an extinction debt in WKHs may exist among specific species confined to coarse dead wood and old-growth forest habitat. Generalist species that also occur in the surrounding matrix showed no negative trends, or actually increased in site occupancy, making future extinctions less likely. Thus, continuing loss of threatened species are likely if not preservation of WKHs are combined with other conservation efforts in managed forest landscapes. Natural forest landscapes may serve as important references when aiming to identify species in risk of future extinction but more detailed knowledge about the biology of the most vulnerable species is also required.

  • 27.
    Berglund, Håkan
    et al.
    Dept of Ecology, SLU Uppsala.
    O'Hara, Robert
    Dept of Mathematics and Statistics, Helsinki University.
    Jonsson, Bengt Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Quantifying habitat requirements of tree-living species in fragmented boreal forests with Bayesian methods2009In: Conservation Biology, ISSN 0888-8892, E-ISSN 1523-1739, Vol. 23, no 5, 1127-1137 p.Article in journal (Refereed)
    Abstract [en]

    Quantitative conservation objectives require detailed consideration of the habitat requirements of target species. Tree-living bryophytes, lichens, and fungi are a critical and declining biodiversity component of boreal forests. To understand their requirements, Bayesian methods were used to analyze the relationships between the occurrence of individual species and habitat factors at the tree and the stand scale in a naturally fragmented boreal forest landscape. The importance of unexplained between-stand variation in occurrence of species was estimated, and the ability of derived models to predict species' occurrence was tested. The occurrence of species was affected by quality of individual trees. Furthermore, the relationships between occurrence of species at the tree level and size and shape of stands indicated edge effects, implying that some species were restricted to interior habitats of large, regular stands. Yet for the habitat factors studied, requirements of many species appeared similar. Species occurrence also varied between stands; most of the seemingly suitable trees in some stands were unoccupied. The models captured most variation in species occurrence at tree level. They also successfully accounted for between-stand variation in species occurrence, thus providing realistic simulations of stand-level occupancy of species. Important unexplained between-stand variation in species occurrence warns against a simplified view that only local habitat factors influence species' occurrence. Apparently, similar stands will host populations of different sizes due to historical, spatial, and stochastic factors. Thus, habitat suitability cannot be assessed simply by population sizes, and stands lacking a species may still provide suitable habitat and merit protection.

     

  • 28.
    Berglund, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Litorina Sea shore displacement and pollen analytical indications of forest succession during the Mid-Holocene in Gästrikland, east central Sweden2010In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 132, no 3, 213-226 p.Article in journal (Refereed)
    Abstract [en]

    This paper deals with the mid-Holocene shore level history and vegetation development in Gästrikland, east-central Sweden. This is investigated using sediment and microfossil records and 14C datings. The time span covered is c. 8000-5000 cal yr BP. Vegetation history during this time includes an increase in Tilia pollen 6500-6300 cal yr BP and a decrease in Ulmus and Corylus c. 5500 cal yr BP. The former change coincides with a sharp drop in relative sea level (RSL) of some 5 m; this RSL drop can be correlated to the regression from the L3 transgression of the Litorina Sea, identified in other areas around the Baltic Sea. The possible connections between RSL and climate (in particular changes on a maritime-continental continuum), as indicated by new pollen data and other records, are investigated. The new material shows, in comparison to other pollen records from southern and central Scandinavia, unusually high percentages of Tilia, Ulmus and Corylus pollen, but less Quercus. The change in pollen spectra around 5500 cal yr BP can be correlated to the northern European “elm decline”. A regional cooling is recorded in widespread data for this time, but observations suggest that other factors must be considered here, including disease and change in the physical landscape due to the ongoing land uplift.

  • 29.
    Berglund, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Time-transgressive early Holocene vegetational succession following shore displacement: a case study from central Sweden2008In: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 37, no 1, 87-101 p.Article in journal (Refereed)
    Abstract [en]

    Deglaciation took place in eastern Jamtland and Angermanland in central Sweden c. 10 500 - 10 200 cal. yr BP. In the present study, vegetation development and shore displacement during the earliest ice-free period are investigated by C-14 dating of sediment from six isolated lake basins and by pollen analysis. A brief but distinct peak in Hippophae "occurs in all pollen diagrams coincident with basin isolation, followed by up to 500 years ( varying locally) by an Alnus rise. The Alnus curve does not display a synchronous rise in the area. Its expansion below the highest shore level is time-transgressive and controlled mainly by the timing of basin isolation. The relationship between regional Alnus expansion and changes in hydrology and climate is discussed. The pollen diagrams show Pinus predominance with Corylus to the east ( more coastal areas) and Betula predominance ( though less pronounced) to the west during the period 10 200 - 9000 cal. yr BP. However, comparisons between sites suggest marked variability in the forest development. Shore displacement in easternmost Jamtland c. 10 300 - 9000 cal. yr BP is equal to or slightly more rapid than that of SE Angermanland, contrary to the present pattern of isostatic recovery. A rapid shore level regression c. 10 300 - 10 000 cal. yr BP may be related to drainage of the Ancylus Lake.

  • 30.
    Björkqvist, Olof
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Fridén, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Concepts of Steam Recovery from LC-Refining by Increase Temperature2009In: Proceedings - 2009 International Mechanical Pulping Conference, IMPC 2009, 2009, 190-194 p.Conference paper (Refereed)
    Abstract [en]

    In a mechanical pulping process, (TMP) wood is refined to pulp in a process with very high wood utilization. However, the power demand in the process is high. Thus efficient energy recovery, especially steam recov-ery, is very important. In high consistency (HC) refining the pulp wood is refined at high temperature (140°C) and pressure. The high temperature makes it possible to recover process heat with usable steam properties.

    One strategy to decrease the power consumption is to split the refining into two stages, one HC-stage and one low consistency (LC) refining stage. This kind of sys-tem is quite common today. One drawback with LC-refining is that it operates at a low temperature normally below 100°C. Hence, the steam recovery potential from conventional LC-refining is limited.

    In this project, we analyse three concepts of steam re-covery in LC-refining by increasing the temperature in the LC-stage. Two base cases: Conventional HC refin-ing only and conventional HC/LC refining is compared with three steam recovery cases: Pulp/Pulp heat ex-changing, Screw Press Dewatering combined with proc-ess water re-circulation and finally Pulp/Water Heat Exchanging.

    The study shows that it is possible to recover steam from the LC-stage and, hence, increase the energy effi-ciency of a combined HC/LC refining system. The screw press case has the highest steam recovery poten-tial of the HC/LC configurations. An initial economic estimate indicates that steam recovery in LC-refining is profitable compared to a conventional HC/LC-configuration.

  • 31.
    Björkqvist, Olof
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Fridén, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Energiåtervinning vid LC-raffinering – Förstudie2008Report (Other academic)
    Abstract [en]

    Normally, steam recovery from a conventional low consistency (LC) mechanical pulprefining system is not possible. This is due to the fact that the temperature level in theLC-refiner is less than 100°C. The steam with such a low temperature and associatedpressure has limited value in the mill. In this project, we study a concept of increasingthe temperature in the refiner to a level were process steam with higher quality can berecovered. The temperature level can be increased by transferring heat from outgoingpulp or drainage to incoming pulp or water. This makes it possible to recover heat fromthe process.An initial estimate indicates that steam recovery from LC-refining systems may have agood economic potential. Three cases have been analyzed: Case A: Steam recovery incombination with pulp/pulp heat exchanging, Case B: Steam recovery in combinationwith a pressurized screw press and finally Case C: steam recovery in combination withpump/water heat exchanging.Case B show the best specific steam recovery, 87% kWh recovered steam per kWh usedelectricity. This concept has a lower technological uncertainty compared to cases A andC as it does not need heat exchanging from pulp.The specific heat recovery from case A and C is 78% and 82% respectively. However,the suggested heat exchangers used in these cases do not exist on the market today.There is hence a need for development of exchangers that can handle pulp with highviscosity. The technological risk associated with the screw press scenario is lower and itis likely that this concept is easier to implement.

  • 32.
    Björkqvist, Olof
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Htun, Myat
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    FORE – Ett nytt industrikombinat baserat på mekaniska massaprocesser2010In: Svensk papperstidning, Nordisk cellulosa, ISSN 1101-766X, no 2, 24-25 p.Article in journal (Other (popular science, discussion, etc.))
  • 33.
    Björkqvist, Olof
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Idefeldt, Jim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Larsson, Aron
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Risk Assessment of New Pricing Strategies in the District Heating Market: A Case Study at Sundsvall Energi AB2010In: Energy Policy, ISSN 0301-4215, Vol. 38, no 5, 2171-2178 p.Article in journal (Refereed)
    Abstract [en]

    The price structure of district heating has been no major scientific issue for the last decades in energy related research. However, today trends in district heating pricing tend to move towards a more customer oriented approach with fixed prices under a longer period, leading to a more complex price structure. If a district heating supplier offers district heating with fixed prices in order to compete with similar electricity offers, the financial risk of the fixed price product is significantly higher than the risk of an ordinary variable cost offer. In contrary to an electricity seller, the district heating company can not transfer all of the risk of fixed prices offer to the financial market, instead the company is thrown upon its own ability to handle the risk by, e.g., hedging its own energy purchase. However, all uncertainties can not be coped with in this manner. Thus, there is a need for a methodology that can be used to estimate the financial risk of different price structures and to value different opportunities to reduce the risk. In this article we propose a methodology, implemented in a prototype software, to evaluate the risk associated with new price structures in district heating.

  • 34.
    Blomquist, Nicklas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Paper based Supercapacitors for vehicle KERS-application2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    High mobility has been a standard in the modern world for decades. This has resulted in high energy consumption, diminishing fossil energy reserves and rising levels of greenhouse gases.

    By recovering the energy lost in deceleration of vehicles the total energy consumption can be decreased and exhaust emissions reduced. This can be done with a kinetic energy recovery system (KERS) that converts kinetic energy to electric energy during deceleration, which then can be used for acceleration.

    KERS requires an electrical storage device with high power density, due to the high power levels generated at heavy braking. Batteries does not generally meet these requirements, especially in the cost-effective point of view, but different types of capacitors can be used to obtain a cheap and effective system. To get such an energy storage device small, lightweight and inexpensive while the technology is sustainable requires avoidance of rare metals and hazardous materials.

    In this master thesis energy and power levels for KERS has been modelled, based on standardized measurements techniques and small paper-based supercapacitors have been built and tested in order to model size, weight and price for a full-scale energy storage device to a KERS-application.

    The models showed that energy consumption in urban traffic could be reduced with 18% and with an electrode material for the energy storage device with a capacitance of about 1500 F/m2 a reasonable size and weight is obtained. To reach these values of capacitance in paper-based supercapacitors further testing is required on area and layer dependence and for different electrodes. 

  • 35.
    Bohlin, Erik
    et al.
    Karlstad Universitet.
    Gustafsson Coppel, Ludovic
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Johansson, Caisa
    Karlstads Universitet.
    Edström, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Modelling of brightness decrease in coated cartonboard as an effect of calendering: Microroughness and effective refractive index aspects2010In: 11th Advanced Coating Fundamentals Symposium Proceedings: The Latest Advances in Coating Research and Development, Norcross, GA, USA: TAPPI Press, 2010, 51-65 p.Conference paper (Refereed)
    Abstract [en]

    Calendering of coated paper leads to a brightness decrease. The mechanism for this is not clear, although it has been discussed in the past. One common explanation is that the porosity of the coating layer decreases and hence scattering. By comparing simulated and measured results this paper shows that modifications of the surface properties account for the brightness decrease of GCC coated substrates with calendering. The effect of a deformable cartonboard substrate is investigated here and compared to a less deformable plastic film substrate. From simulations based on a two-layer Kubelka-Munk model, it is shown that the brightness decrease of the cartonboard due to calendering has a negligible contribution to the brightness decrease of the coated cartonboard. The brightness decrease was similar for coated plastic film and coated cartonboard. The thickness of GCC coated plastic films was not affected by calendering irrespectively of the pigment and latex size distribution. Monte Carlo light scattering simulations, taking into account the measured decrease of surface microroughness and increased effective refractive index, showed that surface modifications accounted for most of the observed brightness decrease of the GCC coated substrate, whereas the bulk scattering and absorption coefficients were not affected by calendering. It is also shown that the scattering coefficient is significantly dependent on the coat weight whereas the physical absorption coefficient is not.

  • 36. Bohman, B
    et al.
    Nordenhem, H
    Sunnerheim, Kerstin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Borg-Karlson, A-K
    Unelius, C R
    Structure-activity relationships of phenylpropanoids as antifeedants for the pine weevil Hylobius abietis2008In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 34, no 3, 339-352 p.Article in journal (Refereed)
    Abstract [en]

    Ethyl cinnamate has been isolated from the bark of Pinus contorta in the search for antifeedants for the pine weevil, Hylobius abietis. Based on this lead compound, a number of structurally related compounds were synthesized and tested. The usability of the Topliss scheme, a flow diagram previously used in numerous structure-activity relationship (SAR) studies, was evaluated in an attempt to find the most potent antifeedants. The scheme was initially followed stepwise; subsequently, all compounds found in the scheme were compared. In total, 51 phenylpropanoids were tested and analyzed for SARs by using arguments from the field of medicinal chemistry (rational drug design). Individual Hansch parameters based on hydrophobicity, steric, and electronic properties were examined. The effects of position and numbers of substituents on the aromatic ring, the effects of conjugation in the molecules, and the effects of the properties of the parent alcohol part of the esters were also evaluated. It proved difficult to find strong SARs derived from single physicochemical descriptors, but our study led to numerous new, potent, phenylpropanoid antifeedants for the pine weevil. Among the most potent were methyl 3-phenylpropanoates monosubstituted with chloro, fluoro, or methyl groups and the 3,4-dichlorinated methyl 3-phenylpropanoate.

  • 37.
    Borell, Stefan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    The Ball Embedding Property of the Open Unit Disc2011In: Proceedings of the American Mathematical Society, ISSN 0002-9939, E-ISSN 1088-6826, Vol. 130, no 10, 3573-3581 p.Article in journal (Refereed)
    Abstract [en]

    We prove that the open unit disc Delta in C satisfies the ball embedding property in C(2); i.e., given any discrete set of discs in C(2) there exists a proper holomorphic embedding Delta hooked right arrow C(2) which passes arbitrarily close to the discs. It is already known that C does not satisfy the ball embedding property in C(2) and that Delta satisfies the ball embedding property in C(n) for n > 2.

  • 38.
    Breistein, Palle
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Development of highly enantioselective organocatalyzed transformations2011Doctoral thesis, comprehensive summary (Other academic)
  • 39.
    Breistein, Palle
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Johansson, Jonas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Ibrahem, Ismail
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Lin, S.
    Deiana, Luca
    Sun, J.
    Córdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    One-step catalytic enantioselective 5-hydroxy-α-quaternary proline synthesis: An asymmetric entry to highly functionalized α-quaternary proline derivativesManuscript (preprint) (Other academic)
  • 40. Brinza, Loredana
    et al.
    Nygård, Charlotta A
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Dring, Matthew J
    Gavrilescu, Maria
    Benning, Liane G
    Cadmium tolerance and adsorption by the marine brown alga Fucus vesiculosus from the Irish Sea and the Bothnian Sea2009In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 100, no 5, 1727-1733 p.Article in journal (Refereed)
    Abstract [en]

    Cadmium (Cd) uptake capacities and Cd tolerance of the marine alga Fucus vesiculosus from the Irish Sea (salinity 35 psu) and from the Bothnian Sea (northern Baltic, 5 psu) were quantified. These data were complemented by measurements of changes in maximal photosynthetic rate (Pmax), dark respiration rate and variable fluorescence vs. maximal fluorescence (Fv:Fm). At concentrations between 0.01 and 1 mmol Cd l−1, F. vesiculosus from the Bothnian Sea adsorbed significantly more (about 98%) Cd compared with F. vesiculosus from the Irish Sea. The photosynthetic measurements showed that the Bothnian Sea F. vesiculosus were more sensitive to Cd exposure than the Irish Sea algae. The algae from the Irish Sea showed negative photosynthetic effects only at 1 mmol Cd l−1, which was expressed as a decreased Pmax (−12.3%) and Fv:Fm (−4.6%). On the contrary, the algae from the Bothnian Sea were negatively affected already at Cd concentrations as low at 0.1 mmol Cd l−1. They exhibited increased dark respiration (+11.1%) and decreased Fv:Fm (−13.9%). The results show that F. vesiculosus from the Bothnian Sea may be an efficient sorption substrate for Cd removal from Cd contaminated seawater and this algae type may also have applications for wastewater treatment.

  • 41.
    Brumelis, Guntis
    et al.
    Univ Latvia, Fac Biol, LV-1586 Riga, Latvia.
    Jonsson, Bengt Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Kouki, Jari
    Univ Eastern Finland, Sch Forest Sci, Joensuu, Finland.
    Kuuluvainen, Timo
    Univ Helsinki, Dept Forest Sci, FIN-00014 Helsinki, Finland.
    Shorohova, Ekaterina
    St Petersburg State Forest Acad, St Petersburg, Russia.
    Forest Naturalness in Northern Europe: Perspectives on Processes, Structures and Species Diversity2011In: Silva Fennica, ISSN 0037-5330, Vol. 45, no 5, 807-821 p.Article in journal (Refereed)
    Abstract [en]

    Saving the remaining natural forests in northern Europe has been one of the main goals to halt the ongoing decline of forest biodiversity. To facilitate the recognition, mapping and efficient conservation of natural forests, there is an urgent need for a general formulation, based on ecological patterns and processes, of the concept of "forest naturalness". However, complexity, structural idiosyncracy and dynamical features of unmanaged forest ecosystems at various spatio-temporal scales pose major challenges for such a formulation. The definitions hitherto used for the concept of forestnaturalness can be fruitfully grouped into three dimensions: 1) structure-based concepts of natural forest, 2) species-based concepts of natural forest and 3) process-based concepts of natural forest. We propose that explicit and simultaneous consideration of all these three dimensions of naturalness can better cope with the natural variability of forest states and also aid in developing strategies for forest conservation and management in different situations. To become operational, criteria and indicators of forest naturalness need to integrate the three dimensions by combining species (e.g. red-listed-, indicator- and umbrella species) with stand and landscape level structural features that are indicative of disturbance and succession processes.

  • 42. Bäckström, Marie
    et al.
    Hammar, Lars-Åke
    Htun, Myat
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Beatability and runnability studies of ion-exchanged unbleached kraft pulps on a pilot scale2009In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 24, no 1, 94-100 p.Article in journal (Refereed)
    Abstract [en]

    It has earlier been shown that the counter-ion to the charged groups in the fibre has a significant effect on the beatability of fibres, but large-scale investigations of this effect are scarce in the literature. The objectives of the present study were therefore to develop a technique to ion-exchange large quantities of industrial pulp into the Na+-form using complexing agents and to study the effect of industrial-scale refining on pulp fibres in the Na+-form and how the fibres respond to industrial-like papermaking. The results show that ion-exchange can indeed be conducted on a pilot-scale using complexing agents such as DTPA. The study further indicates that an energy reduction of 50% at a given WRV or tensile index may be achieved if the fibres are converted to Na+-form prior to pilot-scale refining. By applying these techniques in full-scale production, it should thus be possible to save significant amount of energy, especially in the case of papers made from unbleached pulp that usually demands a higher degree of beating to achieve sufficient strength.

  • 43.
    Bång, Joakim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Purification, Stereoisomeric Analysis and Quantification of Biologically Active Compounds in Extracts from Pine Sawflies, African Butterflies and Orchid Bees2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Stereochemistry plays an important role in nature because biologically important molecules such as amino acids, nucleotides and sugars, only exist in enantiomerically pure forms. Semiochemicals carry messages, between the same species (pheromones) and between different species (allelochemicals). Both pheromones and allelochemicals can be used as environmentally friendly pest management. Many semiochemicals, i.e. behaviour modifying chemicals, consist of pure or well-defined mixtures of stereoisomers, where some of the other stereoisomers can be repellent. It is therefore important to be able to separate them to produce a synthetic pheromone in a mixture that is attractive.

    Pine sawflies are a family of insects that in some cases can be severe defoliators of conifer trees. Diprion pini, Diprion similis and Neodiprion sertifer are severe pests for these trees and have got the most attention in pine sawfly pheromone studies. The pheromone precursors are stored in the female body as long-chain secondary alcohols, which, when released, are esterified to acetates or propionates. The alcohols are chiral, and normally one of the stereoisomer is the main pheromone component, sometimes possible together with other stereoisomers as essential minor components.

    Bicyclus is a genus of African butterflies, and especially Bicyclus anynana has become a popular model for the study of life history evolution, morphology, mating choice and genetics. The wing pattern of Bicyclus differs depending on the season, with large eyespots during the rain-season and small or absent spots during the dry season.

     Euglossa is one of the genera among the orchid bees in the Neotropics that does not produce its own pheromone. Instead, the males collect fragrances from orchids and other sources and store them in a pocket in their hind legs. Both Bicyclus and Euglossa use semiochemicals similar to pine sawflies, and thus can be analysed by the same methods.

    Pheromones and other semiochemicals in insects are often present in low amounts in a complex matrix, and purification of the sample before chemical analysis is often required. A common method is gradient elution on a solid phase silica column. Separation of stereoisomers can be achieved either by using a column with a chiral stationary phase (CSP) or with pre-column derivatisation using a column with an achiral stationary phase (ASP) or a combination of both, with mass detection as the dominant detection method. The purpose of this work has been to improve the purification method, find suitable methods to separate the stereoisomers of secondary alcohols, and to apply this on extracts of insects.

    By selecting the right fractions to collect during gradient elution the purification method was optimised. To reduce plasticizer contamination from ordinary columns, solid phase columns of Teflon or glass were used. For pre-column derivatisation of different chiral alcohols various acid chlorides were tested. For the pine sawfly pheromone precursors enantiopure (2S)-2-acetoxypropionyl chloride was the best choice. To separate some of the stereoisomers achiral 2-naphthoyl chloride was used. For derivatisation of 6,10,14-trimethylpentadecan-2-ol (R)-trans-chrysanthemoyl chloride was the best choice. The derivatised alcohols were separated on different columns, both chiral and non-chiral. Varian FactorFour VF-23ms was chosen as a general-purpose column, the Agilent HP-88 column was the best column with an ASP of those tested, and the Chiraldex B-PA column (CSP) was the only one that could separate all eight stereoisomers of derivatised 3,7-dimethylundecan-2-ol, 3,7-dimethyldodecan-2-ol, and 3,7-dimethyltridecan-2-ol.

    To determine the stereoisomeric purity of standard solutions used in field experiments and extracts of different species of insects the optimised methods were applied. For extracts from B. anynana, Euglossa and Neodiprion lecontei this work describe the first determination of the stereochemistry of some of their semiochemicals.

    For the determination of the stereochemistry of chiral semiochemicals the methods for purification and separation presented herein have shown to be of great value. The results will hopefully contribute to a better understanding of the communication among insects, and ultimately to a more environmentally friendly pest control.

  • 44.
    Bång, Joakim
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Sjödin, Kristina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Purification, Stereoisomeric Analysis and Quantification of Sex Pheromone Precursors in Female Whole Body Extracts from Pine Sawfly Species2011In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 37, no 1, 125-133 p.Article in journal (Refereed)
    Abstract [en]

    A GC-MS method to analyze the stereoisomeric composition of chiral secondary alcohols found in whole body extracts of pine sawfly females was developed. The tested alcohols were derivatized with optically pure (S)-2-acetoxypropionyl chloride prior to GC-MS analysis. Baseline separation was obtained for all sixteen stereoisomers of 3,7,9-trimethyltridecan-2-ol and for the four 3-methylpentadecan-2-ol stereoisomers. For 3,7-dimethyltridecan-2-ol, 3,7-dimethyltetradecan-2-ol and 3,7-dimethylpentadecan-2-ol baseline separation was obtained for 6 of the possible 8 stereoisomers. When a mixture of 16 stereoisomers of 3,7,11-trimethyltridecan-2-ol was tested, baseline separation of 7 peaks out of 16 possible was obtained. The investigated alcohols are pheromone precursors for some pine sawfly species that are severe defoliators of pine. Females from several Diprion, Neodiprion, Macrodiprion, Microdiprion, and Gilpinia species emit esters of such secondary alcohols as sex pheromones that attract males for mating. To quantify the small amounts of the precursor alcohol and its stereoisomeric composition found in whole body extracts from female pine sawflies, a purification method was optimized. An extract of 20 females of D. pini contained about 8 ng of (2 S,3 R,7 R)-3,7-dimethyltridecan-2-ol per female, and three extracts of 18, 20, and 90 females of N. sertifer contained between 5 and 13 ng of (2 S,3 S,7 S)-3,7-dimethylpentadecan-2-ol per female.

  • 45.
    Bång, Åsa
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Jonsson, Bengt Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Holm, Svante
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Equal seed set and germination rate over distance and indication of self incompatibility in artificial crosses of Filipendula ulmariaManuscript (Other academic)
  • 46.
    Bång, Åsa
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Jägbrant, Veronica
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Holm, Svante
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Spatial genetic structure of a common riparian plant species, Meadowsweet (Filipendula ulmaria) in northern SwedenManuscript (Other academic)
  • 47.
    Carillo, Sandra
    et al.
    Universita Roma La Sapienza.
    Schiebold, Cornelia
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    A non-commutative operator-hierarchy of Burgers equations and Bäcklund transformations2009In: Series on Advances in Mathematics for Applied Sciences, ISSN 1793-0901, Vol. 82Article in journal (Refereed)
  • 48.
    Carillo, Sandra
    et al.
    Universita Roma La Sapienza.
    Schiebold, Cornelia
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Matrix KdV and mKdV hierarchies: Noncommutative soliton solutions and explicit formulae2009Report (Other academic)
  • 49.
    Carillo, Sandra
    et al.
    Univ Roma La Sapienza, Dipartimento Sci Base & Applicate Ingn, Sez Matemat, Rome, Italy .
    Schiebold, Cornelia
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Matrix Korteweg-de Vries and modified Korteweg-de Vries hierarchies: Noncommutative soliton solutions2011In: Journal of Mathematical Physics, ISSN 0022-2488, E-ISSN 1089-7658, Vol. 52, no 5, Art. no. 053507- p.Article in journal (Refereed)
    Abstract [en]

    The present work continues work on KdV-type hierarchies presented by S. Carillo and C. Schiebold ["Noncommutative Korteweg-de Vries and modified Korteweg-de Vries hierarchies via recursion methods," J. Math. Phys. 50, 073510 (2009)]. General solution formulas for the KdV and mKdV hierarchies are derived by means of Banach space techniques both in the scalar and matrix case. A detailed analysis is given of solitons, breathers, their countable superpositions as well as of multisoliton solutions for the matrix hierarchies. (C) 2011 American Institute of Physics. [doi:10.1063/1.3576185]

  • 50.
    Carillo, Sandra
    et al.
    Universita Roma La Sapienza.
    Schiebold, Cornelia
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Noncommutative Korteweg-de Vries and modified Korteweg-de Vries hierarchies via recursion methods2009In: Journal of Mathematical Physics, ISSN 0022-2488, E-ISSN 1089-7658, Vol. 50, no 7, 073510Article in journal (Refereed)
    Abstract [en]

    Here, noncommutative hierarchies of nonlinear equations are studied. They represent a generalization to the operator level of corresponding hierarchies of scalar equations, which can be obtained from the operator ones via a suitable projection. A key tool is the application of Baumlcklund transformations to relate different operator-valued hierarchies. Indeed, in the case when hierarchies in 1+1-dimensions are considered, a "Baumlcklund chart" depicts links relating, in particular, the Korteweg-de Vries (KdV) to the modified KdV (mKdV) hierarchy. Notably, analogous links connect the hierarchies of operator equations. The main result is the construction of an operator soliton solution depending on an infinite-dimensional parameter. To start with, the potential KdV hierarchy is considered. Then Baumlcklund transformations are exploited to derive solution formulas in the case of KdV and mKdV hierarchies. It is remarked that hierarchies of matrix equations, of any dimension, are also incorporated in the present framework.

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