miun.sePublications
Change search
Refine search result
123 1 - 50 of 119
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Afewerki, Samson
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Direct regiospecific and highly enantioselective intermolecular a-allylic alkylation of aldehydes by combination of transition metal and chiral amine catalysts2012Conference paper (Refereed)
    Abstract [en]

    The direct intermolecular regiospecific and highly enantioselective a-allylic alkylation of linear aldehydes by combination of achiral bench stable Pd(0) complexes and simple chiral amines as co-catalysts is disclosed. The co-catalytic asymmetric chemoselective and regiospecific a-allylic alkylation reaction is linked in tandem with in situ reduction to give the corresponding 2-alkyl alcohols with high enantiomeric ratios (up to 98:2 er). It is also an expeditious entry to valuable 2-alkyl substituted hemiacetals and 2-alkyl-butane-1,4-diols.

  • 2.
    Afewerki, Samson
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Ibrahem, Ismail
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Rydfjord, Jonas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Breistein, Palle
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Córdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Direct Regiospecific and Highly Enantioselective Intermolecular α-Allylic Alkylation of Aldehydes By Combination of Transition Metal and amine Catalysts2012In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 10, p. 2972-2977Article in journal (Refereed)
    Abstract [en]

    The first direct intermolecular regiospecific and highly enantioselective α-allylic alkylation of linear aldehydes by a combination of achiral bench-stable Pd 0 complexes and simple chiral amines as co-catalysts is disclosed. The co-catalytic asymmetric chemoselective and regiospecificα-allylic alkylation reaction is linked in tandem with in situ reduction to give the corresponding 2-alkyl alcohols with high enantiomeric ratios (up to 98:2 e.r.; e.r.=enantiomeric ratio). It is also an expeditious entry to valuable 2-alkyl substituted hemiacetals, 2-alkyl-butane-1,4-diols, and amines. The concise co-catalytic asymmetric total syntheses of biologically active natural products (e.g., Arundic acid) are disclosed. Go organic! Directintermolecular regiospecific and highly enantioselective α-allylic alkylation of linear aldehydes by a combination of achiral bench-stable Pd 0complexes and simple chiral amines as co-catalysts is disclosed (see scheme). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • 3.
    Ali, S.
    et al.
    Univ Stockholm, Dept Phys, S-10691 Stockholm, Sweden.
    Orban, I.
    Univ Stockholm, Dept Phys, S-10691 Stockholm, Sweden.
    Mahmood, S.
    Univ Stockholm, Dept Phys, S-10691 Stockholm, Sweden.
    Altun, Z.
    Marmara Univ, Dept Phys, TR-81040 Istanbul, Turkey.
    Glans, Peter
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Schuch, R.
    Univ Stockholm, Dept Phys, S-10691 Stockholm, Sweden.
    ELECTRON-ION RECOMBINATION RATE COEFFICIENTS FOR C II FORMING C I2012In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 753, no 2, p. Art. no. 132-Article in journal (Refereed)
    Abstract [en]

    We have determined absolute dielectronic recombination rate coefficients for C II, using the CRYRING heavy-ions storage ring. The resonances due to 2s-2p (Delta n= 0) core excitations are detected in the center-of-mass energy range of 0-15 eV. The experimental results are compared with intermediate coupling AUTOSTRUCTURE calculations. Plasma rate coefficients are obtained from the DR spectrum by convoluting it with a Maxwell-Boltzmann energy distribution for temperatures in the range of 10(3)-10(6) K. The derived temperature-dependent plasma recombination rate coefficients are presented graphically and parameterized by using a fit formula for convenient use in plasma modeling codes. The experimental rate coefficients are also compared with the theoretical data available in literature. In the temperature range of 10(3)-2 x 10(4) K, our experimental results show that previous calculations severely underestimate the plasma rate coefficients and also our AUTOSTRUCTURE calculation does not reproduce the experimental plasma rate coefficients well. Above 2x10(4) K, the agreement between the experimental and theoretical rate coefficients is much better, and the deviations are smaller than the estimated uncertainties.

  • 4.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Andres, Britta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    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 applied science and design.
    Hummelgård, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Bäckström, Joakim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Zhang, Renyun
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Contacting paper-based supercapacitors to printed electronics on paper substrates2012In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, no 2, p. 476-480Article in journal (Refereed)
    Abstract [en]

    Hybrid printed electronics, in which printed structures and silicon-based components co-exist will likely be among the first commercial solutions. In this case the paper substrate acts much in the same way as circuit boards, containing conductive tracks and acting as a carrier for the electrical components. It is important to consider the contacting of the components to be able to produce low resistance electrical contacts to the conductive tracks. Supercapacitors are able to deliver a large amount of current in a short time and are a good option for short term energy storage and if the printed product is to be used only one, or a few times, it can be the only power source needed. When manufacturing printed electronics, the overall resistance of the printed tracks as well as the contact resistance of the mounted components will add up to the total resistance of the system. A high resistance will cause a voltage drop from the power source to the component. This will waste power that goes to Joule heating and also the voltage and current available to components may be too low to drive them. If the intention is to use a power supply such as batteries or solar cells this becomes a limitation. In this article have been tested several conductive adhesives used to contact paper based supercapacitors to ink jet printed silver tracks on paper. The best adhesive gives about 0.3 Ω per contact, a factor 17 better compared to the worst which gave 5 Ω. The peak power that is possible to take out from a printed system with a flexible battery and super capacitors is about 10 times higher than compared with the same system with only the battery.

  • 5.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Hammarling, Krister
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Sidén, Johan
    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.
    Öhlund, Thomas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Modified EAS Tag Used as a Resistive Sensor Platform2012In: MDPI Electronics, ISSN 2079-9292, Vol. 1, no 2, p. 32-46Article in journal (Refereed)
    Abstract [en]

    In this article, a modified design of an RF Radio Frequency Electronic ArticleSurveillance (EAS) tag, used as a sensor platform, is manufactured and characterized. EAStags are passive devices consisting of a capacitor and coil, tuned to a resonance frequencyreadable by the detector equipment, in this case 8.2 MHz. They were originally used todetect whether merchandise was being moved through the detection gates at shop exits, inwhich case an alarm was triggered. If the capacitance is divided in two and a resistivesensor device inserted in between, the resonant Inductor-Capacitor (LC) circuit becomes anInductor-Capacitor-Capacitor-Resistor LCCR circuit and can be used as a sensor tag. Ahigh sensor resistance means that one capacitor is decoupled, leading to one resonancefrequency, while a low resistance will couple both capacitances into the circuit, resulting ina lower resonance frequency. Different types of resistive sensors exist that are able todetect properties such as pressure, moisture, light and temperature. The tag is manufacturedin Aluminum foil on a polyetylentereftalat (PET) substrate, resulting in a cost effectiveRF-platform for various resistive sensors. Two types of tags are designed andmanufactured, one with parallel plate capacitors and the other with interdigital capacitors.To test the tags, a resistive tilt sensor is mounted and the tags are characterized using anetwork analyzer. It is shown that for high resistance, the tags have a resonance frequencyof more than 10 MHz while for low values the frequency approaches 8.2 MHz.

  • 6.
    Andersson, Henrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Lidenmark, Cecilia
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Öhlund, Thomas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Örtegren, Jonas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    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 Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Evaluation of coatings applied to flexible substrates to enhance quality of ink jet printed silver nano-particle structures2012In: IEEE Transactions on Components, Packaging, and Manufacturing Technology, Part C, ISSN 1083-4400, E-ISSN 1558-1241, Vol. 2, no 2, p. 342-348Article in journal (Refereed)
    Abstract [en]

    Different types of the commercial surface treatment InkAid have been evaluated as a surface treatment to enhance print quality of silver nano-particle ink structures printed on polyimide and polyethene substrate. Originally these coatings have been specified to be applied on substrates for graphical ink jet printing. On the coated polyimide and polyethene substrates lines of different widths have been printed using a Dimatix materials printer together with silver nano-particle ink manufactured by Advanced Nano Products. The prints have then been evaluated in terms of print quality and resistivity before and after sintering. The results show that the application of these coatings can improve the print quality considerably, making it possible to print lines with a good definition, which is not  otherwise possible with this type of ink on this substrate types. It has been found that the coating Semi Gloss provides the best results, both in terms of print quality as well as the lowest resistivity. The resistivity on polyethene is 3.5*10-7Ωm at best when sintered at 150°C and for polyimide  8.9*10-8Ωm sintered at 200°C. This corresponds to a conductivity of about  4.5% and  18%of bulk silver, respectively. It can be concluded that applying such PVP based coatings to polyethene and polyimide will increase the print quality quite substantially, making it possible to print patterns with requirements of smaller line widths and more details than what is possible without coating.

  • 7.
    Andersson, Henrik
    et al.
    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.
    Unander, Tomas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Lidenmark, Cecilia
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Forsberg, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Inkjet printed silver nanoparticle humidity sensor with memory effect on paper2012In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 12, no 6, p. 1901-1905Article in journal (Other academic)
    Abstract [en]

    In this paper, the design and the manufacture of an inkjet printed resistive type humidity sensor on paper are reported. After having been exposed to humidity above a given threshold level, the resistance of the sensor decreases substantially and remains at that level even when thehumidity is reduced. It is possible to deduce the humidity level by monitoring the resistance. The main benefit of the printed sensor presented in this case is in relation to its very low production costs. It has also been shown that both the ink type and this paper combination used prove to be crucial in order to obtain the desired sensor effect. More research is required in order to fully understand the humidity sintering effect on the nano particle ink and the role of the substrate. However, the observed effect can be put to use in printed humidity sensors which possess a memoryfunction. The sensor can be used in various applications for environmental monitoring, for example, in situations where a large number of inexpensive and disposable humidity sensors are required which are able to detect whether they have been subjected to high humidity. This could be the checking of transportation conditions of goods or monitoring humidity within buildings. © 2001-2012 IEEE.

  • 8.
    Andersson, Stefan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Sandberg, Christer
    Holmen Paper AB, Braviken Paper Mill, SE-60188 Norrkoping, Sweden .
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Comparison of mechanical pulps from two stage HC single disc and HC double disc - LC refining2012In: Appita journal, ISSN 1038-6807, Vol. 65, no 1, p. 57-62Article in journal (Refereed)
    Abstract [en]

    A mechanical pulping line consisting of high consistency (HC) double disc (DD) and low consistency (LC) refining was compared with a two stage single disc (SD) high consistency twin refiner line. The purpose of this study was to evaluate specific energy consumption and pulp properties. The two different process solutions were tested running similar Norway spruce wood supply. At similar tensile index and freeness, the DD-LC concept reduced the electric energy consumption by 400 kWh/adt compared with the traditional two-stage SD-SD system. Pulp characteristics of the two refining concepts were compared at tensile index 47 Nm/g. Fibre length was reduced more after DD-LC refining than after SD-SD refining. Specific light scattering coefficient was higher after DD-LC refining than SD-SD refining, while the development in second stage refining was better for SD-SD pulp than for DD-LC pulp. Shive level was significantly lower for DD-LC pulp than for SD-SD pulp.

  • 9.
    Andersson, Stefan
    et al.
    Holmen Paper AB, Bravikens Pappersbruk, SE-601 88 Norrköping, Sweden.
    Sandberg, Christer
    Holmen Paper AB, Bravikens Pappersbruk, SE-601 88 Norrköping, Sweden.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Effect of long fibre concentration on low consistency refining of mechanical pulp2012In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, no 4, p. 702-706Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate the influence of long fibre concentration on loadability and pulp properties during LC refining of mechanical pulp. Long fibre concentration was adjusted to three different levels by screen fractionation of the pulp. The three pulps were refined in a single disc pilot scale LC refiner at similar process conditions. Increased long fibre concentration supported a larger refiner gap and resulted in less fibre cutting at a given specific energy consumption. The higher long fibre concentration probably contributed to a stronger fibre network that maintained a larger refining gap at certain specific energy consumption. Increased long fibre concentration also enabled a higher tensile index increase in the LC refiner at certain fibre length reduction. The study supports a process combining LC refining with screen fractionation, where the long fibre fraction is recycled to the refiner feed. This enables a higher loadability and a more effective utilisation of the LC refiner. By using this technology, overall specific energy consumption can be reduced if a larger share of the refining is performed in LC rather than HC refining.

  • 10.
    Andres, Britta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Supercapacitors with graphene coated paper electrodes2012Conference paper (Refereed)
  • 11.
    Andres, Britta
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Forsberg, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Vilches, Ana Paola
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Zhang, Renyun
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Andersson, Henrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Hummelgård, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Bäckström, Joakim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Supercapacitors with graphene coated paper electrodes2012In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, no 2, p. 481-485Article in journal (Refereed)
    Abstract [en]

    Paper based supercapacitors are prepared by stacking a paper between two graphene electrodes and soaking these in an aqueous electrolyte. We demonstrate that supercapacitors can easily be manufactured by using proven paper technologies. Several different electrode materials were compared and two types of contacting material, silver and graphite foil were tested. The influence of the paper used as separator was also investigated. The supercapacitors with a graphene-gold nanoparticle composite as electrodes showed a specific capacitance of up to 100 F/g and an energy density of 1.27 Wh/kg. The energy density can further be increased by using other electrolytes. The silver contacts showed a pseudo capacitance, which the graphite contacts did not. The papers tested had a minor effect on the capacitance, but they have an influence on the weight and the volume of the supercapacitor.

  • 12.
    Berglund, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Early Holocene in Gästrikland, east central Sweden: Shore displacement and isostatic recovery2012In: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 41, no 2, p. 263-276Article in journal (Refereed)
    Abstract [en]

    In GÀstrikland in central Sweden, deglaciation took place c. 11000cal. a BP. In the present study the shore displacement during the earliest ice-free period is investigated by the 14C dating of sediment from isolated lake basins. The shore displacement in GÀstrikland includes an initial phase (∌500 years) of rapid regression, followed by a slowing of the relative sea level (RSL) fall to a rate similar to that of the remaining Holocene c. 9250cal. a BP. The Ancylus Lake stage of the Baltic Sea belongs to the analysed interval. The RSL curve and glacial unloading history are used to separate and quantify elements of isostatic uplift. The postglacial uplift is ∌260m, of which ∌45m forms a rapid initial rise, which can be treated as qualitatively separate from the later, slower rise. There is considerable glacial unloading just prior to the deglaciation, but calculations suggest that only a small part of this relates directly to the rapid early Holocene rebound: most unloading is transferred either to uplift immediately prior to the deglaciation or to subsequent Holocene or future uplift. The isostatic rise in GÀstrikland occurring between the end of the Younger Dryas stadial and the deglaciation, c. 11500-11000cal. a BP, is estimated to be 100-110m. Observations and estimations are incompatible with a Weichselian maximum ice thickness much smaller that 3000m. The lack of glacial unloading during the Younger Dryas has a measurable impact on the Holocene isostatic rebound in GÀstrikland, reducing it by an estimated 20-25m. © 2011 The Boreas Collegium.

  • 13.
    Berglund, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    THE HIGHEST POSTGLACIAL SHORE LEVELS AND GLACIO-ISOSTATIC UPLIFT PATTERN IN NORTHERN SWEDEN2012In: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 94A, no 3, p. 321-337Article in journal (Refereed)
    Abstract [en]

    The detailed clay varve chronology and an extensive knowledge of the highest postglacial shore level elevation (HS) in northern Sweden, along the Bothnian western coast, provides opportunities for determining the pattern of isostatic rise and centre of uplift from the early Holocene. The shore level of c. 10 100 cal yr bp (10 ka) for this area is determined by subtracting, from the metachronous HS elevations, the fall in relative sea level between local deglaciation time and the chosen reference time. The area of highest uplift since 10 ka is situated somewhat north of the location with the world-record HS (Skuleberget in Angermanland), but south of the area with most rapid current rise. Wave erosion marks in the studied area are seen to be more consistent indicators of HS than glaciofluvial delta levels. The gradients of shore marks at 10 ka are generally small within the investigation area. The regional 10 ka shore level pattern shows considerable irregularity compared to the current uplift. Central Sweden and western Finland show 10 ka gradients that indicate isostatic response to late (1310 ka bp) glacial unloading. Indications of a secondary uplift centre west of the present investigation area are reported in previous work; this also suggests rapid isostatic response to unloading. Finally, the possibility of identifying errors in the varve-dated deglaciation chronology via the 10 ka shore level pattern is illustrated.

  • 14.
    Björkqvist, T.
    et al.
    Department of Automation Science and Engineering, Tampere University of Technology, P.O.B 692, FIN-33100 Tampere, Finland.
    Engberg, Birgitta A.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Salminen, L. I.
    VTT Technical Research Center Finland, P.O.B. 1000, FIN-02044 VTT, Finland.
    Salmi, A.
    VTT Technical Research Center Finland, P.O.B. 1000, FIN-02044 VTT, Finland.
    Towards optimal defibration: Energy reduction by fatiguing pre-treatment2012In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, no 2, p. 168-172Article in journal (Refereed)
    Abstract [en]

    A motive for fatiguing wood prior to defibration would be to reduce the energy consumption needed in mechanical pulping processes. Therefore, the effects of fatiguing pre-treatment were here studied on wood samples, on defibration and also on produced paper. The results indicate that pre-fatiguing changes the mechanic response of wood to be more favorable for harsh defibration which in turn is positive for the process efficiency.

  • 15.
    Bång, Joakim
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Anderbrant, Olle
    Lund Univ, Dept Biol, Lund, Sweden.
    Stereoisomeric separation of derivatized 2-alkanols using gas chromatography – mass spectrometry: Sex pheromone precursors found in pine sawfly species2012In: Analytical Letters, ISSN 0003-2719, E-ISSN 1532-236X, Vol. 45, no 9, p. 1016-1027Article in journal (Refereed)
    Abstract [en]

    Stereoisomers of long-chain secondary alcohols are used as sex pheromone precursors among pine sawflies, which can be severe pest to conifers. To use the pheromone in environmentally friendly pest managements, methods are needed that can determine the exact stereochemistry of the precursor alcohols. Combinations of 11 acid chloride derivatives and 10 GC columns were evaluated for separation of the stereoisomers of 3,7-dimethylundecan-2-ol, 3,7-dimethyldodecan-2-ol, 3,7-dimethyltridecan-2-ol, 3,7-dimethyltetradecan-2-ol, and 3,7-dimethylpentadecan-2-ol. Derivatisation with (2S)-2-acetoxypropionyl chloride in combination with the Chiraldex B-PA column separated all eight stereoisomers of 3,7-dimethylundecan-2-ol, 3,7-dimethyldodecan-2-ol and 3,7-dimethyltridecan-2-ol. A combination of two different derivatisation methods was needed to separate all stereoisomers of the longer chained alcohols, 3,7-dimethyltetradecan-2-ol and 3,7-dimethylpentadecan-2-ol. An extract of the pine sawfly Neodiprion lecontei was also analysed, and the stereochemistry of the sex pheromone alcohol prcursor was determined to be (2S,3S,7S)-3,7-dimethylpentadecan-2-ol, at an amount of about 7 ng/female. This paper presents the first GC-MS-separation of all eight stereoisomers of 3,7-dimethylundecan-2-ol, 3,7-dimethyldodecan-2-ol and 3,7-dimethyltridecan-2-ol in a single analytical run, and also the first determination of the stereochemistry of the sex pheromone precursor of N. lecontei.

  • 16.
    Carillo, Sandra
    et al.
    Dipartimento di Scienze di Base e Applicate per l'Ingegneria Sez. Matematica, SAPIENZA Università di Roma, Rome, Italy.
    Schiebold, Cornelia
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    On the recursion operator for the noncommutative Burgers hierarchy2012In: Journal of Nonlinear Mathematical Physics, ISSN 1402-9251, E-ISSN 1776-0852, Vol. 19, no 1, p. Art. no. 1250003-Article in journal (Refereed)
    Abstract [en]

    The noncommutative Burgers recursion operator is constructed via the ColeHopf transformation, and its structural properties are studied. In particular, a direct proof of its hereditary property is given. © S. Carillo and C. Schiebold.

  • 17.
    Carlsson, Fredrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Edman, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Holm, Svante
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Eriksson, Anna-Maria
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Jonsson, Bengt Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Increased heat resistance in mycelia from wood fungi prevalent in forests characterized by fire: a possible adaptation to forest fire.2012In: Fungal Biology, ISSN 1878-6146, E-ISSN 1878-6162, Vol. 116, no 10, p. 1025-1031Article in journal (Refereed)
    Abstract [en]

    Abstract

    Forest fire has for a long time been the major stand replacing/modifying disturbance in boreal forests. For organisms to adopt to this phenomenon different strategies for protective measurements has evolved. This study focuses on the organism group of wood fungi, and one of several possibilities for adaptation to forest fire - increased heat resistance in the mycelia. 16 species of wood fungi where selected and sorted a priori according to their prevalence for fire affected substrate. These were isolated and re-inoculated on pine wood before testing. Experiments where done in a series where the mycelia was exposed to 100, 140, 180, 220°C for 5, 10, 15, 20, 15 min. A very clear difference was found, the group containing species with a prevalence for a fire affected substrate had a much higher survival rate over all combinations of time and temperature compared to species with a more general ecology. This data suggests that increased heat resistance in mycelia could be a possible adaptation to forest fire. This in turn has major impacts on the ecology and population dynamics of wood fungi. An increase in temperature could shift the population structure in a log, allowing minor non fruiting mycelia content to expand on the expense of earlier dominant colonizers. Furthermore this study has implications on how to control prescribed restoration burning events. When burning areas where the dead wood content is dominated by early decay stages, loss of species can be avoided by proper management.

  • 18.
    Co, M.
    et al.
    Dept Phys & Analyt Chem, Uppsala Univ, POB 599, SE-75124 Uppsala.
    Fagerlund, Amelie
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Engman, L.
    Dept Biochem & Organ Chem, Uppsala Univ, SE-75123 Uppsala.
    Sunnerheim, Kerstin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Sjöberg, P. J.
    Dept Phys & Analyt Chem, Uppsala Univ, POB 599, SE-75124 Uppsala.
    Turner, C.
    Dept Phys & Analyt Chem, Uppsala Univ, POB 599, SE-75124 Uppsala.
    Extraction of Antioxidants from Spruce (Picea abies) Bark using Eco-friendly Solvents2012In: Phytochemical Analysis, ISSN 0958-0344, E-ISSN 1099-1565, Vol. 23, no 1, p. 1-11Article in journal (Refereed)
    Abstract [en]

    Introduction - Antioxidants are known to avert oxidation processes and they are found in trees and other plant materials. Tree bark is a major waste product from paper pulp industries; hence it is worthwhile to develop an extraction technique to extract the antioxidants. Objective - To develop a fast and environmentally sustainable extraction technique for the extraction of antioxidants from bark of spruce (Picea abies) and also to identify the extracted antioxidants that are abundant in spruce bark. Methodology - A screening experiment that involved three different techniques was conducted to determine the best technique to extract antioxidants. The antioxidant capacity of the extracts was determined with DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. Pressurised fluid extraction (PFE) turned out to be the best technique and a response surface design was therefore utilised to optimise PFE. Furthermore, NMR and HPLC-DAD-MS/MS were applied to identify the extracted antioxidants. Results - PFE using water and ethanol as solvent at 160 and 180°C, respectively, gave extracts of the highest antioxidant capacity. Stilbene glucosides such as isorhapontin, piceid and astringin were identified in the extracts. Conclusion - The study has shown that PFE is a fast and environmentally sustainable technique, using water and ethanol as solvent for the extraction of antioxidants from spruce bark. Copyright © 2011 John Wiley and Sons, Ltd. This paper includes four tables in which the extracted solid yield and the antioxidant capacity of spruce bark extracts were presented for the different extraction techniques, as well as the response surface coefficients for the optimised PFE were presented. © 2011 John Wiley and Sons, Ltd..

  • 19.
    Córdova, Armando
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    R., Rios
    Aziridine Formation: in C-N Bond Formation2012In: Comprehensive Chirality / [ed] Yamamoto, H.; Carreira, E. Eds, Oxford: Elsevier, 2012Chapter in book (Refereed)
  • 20.
    Daghighi, Abtin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Approach regions of Lebesgue measurable, locally bounded, quasi-continuous functions2012In: International Journal of Mathematical Analysis, ISSN 1312-8876, E-ISSN 1314-7579, Vol. 6, no 13, p. 659-680Article in journal (Refereed)
    Abstract [en]

    Quasi-continuity (in the sense of Kempisty) generalizes directional continuity of complex-valued functions on open subsets of ℝ n or ℂ n, and in particular provides certain approach regions at every point. We show that these can be used as a proof tool for proving several properties forLebesgue measurable, locally bounded, quasi-continuous functions e.g. that for such a function f the polynomial ring C(M,K)[f] (where K = ℝ or ℂ) satisfies that the equivalence classes under identification a.e. have cardinality one and an asymptotic maximum principle.

  • 21.
    Daghighi, Abtin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    The Maximum Principle for Cauchy-Riemann Functions and Hypocomplexity2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This licentiate thesis contains results on the maximum principle forCauchy–Riemann functions (CR functions) on weakly 1-concave CRmanifolds and hypocomplexity of locally integrable structures. Themaximum principle does not hold true in general for smooth CR functions,and basic counterexamples can be constructed in the presenceof strictly pseudoconvex points. We prove a maximum principle forcontinuous CR functions on smooth weakly 1-concave CR submanifolds.Because weak 1-concavity is also necessary for the maximumprinciple, a consequence is that a smooth generic CR submanifold ofCn obeys the maximum principle for continuous CR functions if andonly if it is weakly 1-concave. The proof is then generalized to embeddedweakly p-concave CR submanifolds of p-complete complexmanifolds. The second part concerns hypocomplexity and hypoanalyticstructures. We give a generalization of a known result regardingautomatic smoothness of solutions to the homogeneous problemfor the tangential CR vector fields given local holomorphic extension.This generalization ensures that a given locally integrable structureis hypocomplex at the origin if and only if it does not allow solutionsnear the origin which cannot be represented by a smooth function nearthe origin.

  • 22.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Quantitative microscopy of coating uniformity2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Print quality demands for coated papers are steadily growing, and achieving coating uniformity is crucial for high image sharpness, colour fidelity, and print uniformity. Coating uniformity may be divided into two scales: coating thickness uniformity and coating microstructure uniformity, the latter of which includes pigment, pore and binder distributions within the coating layer. This thesis concerns the investigation of both types of coating uniformity by using an approach of quantitative microscopy.First, coating thickness uniformity was analysed by using scanning electron microscope (SEM) images of paper cross sections, and the relationships between local coating thickness variations and the variations of underlying base sheet structures were determined. Special attention was given to the effect of length scales on the coating thickness vs. base sheet structure relationships.The experimental results showed that coating thickness had a strong correlation with surface height (profile) of base sheet at a small length scale. However, at a large length scale, it was mass density of base sheet (formation) that had the strongest correlation with coating thickness. This result explains well the discrepancies found in the literature for the relationship between coating thickness variation and base sheet structure variations. The total variance of coating thickness, however, was dominated by the surface height variation in the small scale, which explained around 50% of the variation. Autocorrelation analyses were further performed for the same data set. The autocorrelation functions showed a close resemblance of the one for a random shot process with a correlation length in the order of fibre width. All these results suggest that coating thickness variations are the result of random deposition of particles with the correlation length determined by the base sheet surface textures, such as fibre width.In order to obtain fundamental understandings of the random deposition processes on a rough surface, such as in paper, a generic particle deposition model was developed, and systematic analyses were performed for the effects of particle size, coat weight (average number of particles), levelling, and system size on coating thickness variation. The results showed that coating thickness variation3grows with coat weight, but beyond a certain coat weight, it reaches a plateau value. A scaling analysis yielded a universal relationship between coating thickness variation and the above mentioned variables. The correlation length of coating thickness was found to be determined by average coat weight and the state of underlying surfaces. For a rough surface at relatively low coat weight, the correlation length was typically in the range of fibre width, as was also observed experimentally.Non-uniformities within the coating layer, such as porosity variations and binder distributions, are investigated by using a newly developed method: field emission scanning electron microscopy (FESEM) in combination with argon ion beam milling technique. The combination of these two techniques produced extremely high quality images with very few artefacts, which are particularly suited for quantitative analyses of coating structures. A new evaluation method was also developed by using marker-controlled watershed segmentation (MCWS) of the secondary electron images (SEI).The high resolution imaging revealed that binder enrichment, a long disputed subject in the area, is present in a thin layer of a 500 nm thickness both at the coating surface and at the base sheet/coating interface. It was also found that the binders almost exclusively fill up the small pores, whereas the larger pores are mainly empty or depleted of binder.

  • 23.
    Dahlström, Christina
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Uesaka, Tetsu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Coating Microstructures: Binder Distributions2012In: 12th TAPPI Advanced Coating Fundamentals Symposium Proceedings, Co-located with the 16th International Coating Science and Technology Symposium, ISCST 2012, Tappi , 2012, p. 250-257Conference paper (Other academic)
    Abstract [en]

     Non-uniformities within the coating layer, such as porosity variations and binder distributions, are known to affect print uniformity and barrier properties. However, in the literature the results on coating microstructures are rather limited or sometimes conflicting.We obtained high quality images of coated paper cross sections using field emission scanning electron microscopy in combination with a new argon ion beam milling technique to directly observe and analyse the binder and pore distribution. This technique produces high quality images that allow microstructure characterisation of the coating layer.The binder distribution measurements showed that the binder is almost exclusively filling up the small pores, whereas the larger pores are mainly empty and depleted of binder.

  • 24.
    Dahlström, Christina
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Uesaka, Tetsu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Microstructure Variations in Paper Coating: Direct Observations2012In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 51, no 24, p. 8246-8252Article in journal (Refereed)
    Abstract [en]

    Non-uniformities in the coating layer, such as porosity variations and binder distributions, are known to affect print uniformity and barrier properties. However, in the literature the results are rather scarce or sometimes conflicting.

    We acquired high quality images of coated paper cross sections using field emission scanning electron microscopy in combination with a new argon-ion-beam milling technique to directly observe and analyse the coating microstructures in relation to underlying base sheet structures.

    The results showed that coating porosity varied with mass density of the underlying base sheet for the relatively bulky clay/GCC coating, whereas for the more compact clay coating, the effect was small. Areas with more fibres in the base sheet were more compressed by calendering, resulting in a decreased coating porosity. A unique binder enriched layer of less than 500 nm thickness was found at the coating surface as well as at the coating/base sheet interface.

  • 25.
    Deiana, Luca
    et al.
    Univ Stockholm, Arrhenius Lab, Dept Organ Chem, S-10691 Stockholm, Sweden .
    Afewerki, Samson
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Palo-Nieto, Carlos
    Univ Stockholm, Arrhenius Lab, Dept Organ Chem, S-10691 Stockholm, Sweden .
    Verho, Oscar
    Univ Stockholm, Arrhenius Lab, Dept Organ Chem, S-10691 Stockholm, Sweden .
    Johnston, Eric V
    Univ Stockholm, Arrhenius Lab, Dept Organ Chem, S-10691 Stockholm, Sweden .
    Córdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Highly Enantioselective Cascade Transformations by Merging Heterogeneous Transition Metal Catalysis with Asymmetric Aminocatalysis2012In: Scientific reports, ISSN 2045-2322, Vol. 2, p. Art. no. 851-Article in journal (Refereed)
    Abstract [en]

    The concept of combining heterogeneous transition metal and amine catalysis for enantioselective cascade reactions has not yet been realized. This is of great advantage since it would allow for the recycling of expensive and non-environmentally friendly transition metals. We disclose that the use of a heterogeneous Pd-catalyst in combination with a simple chiral amine co-catalyst allows for highly enantioselective cascadetransformations. The preparative power of this process has been demonstrated in the context of asymmetric cascade Michael/carbocyclizationtransformations that delivers cyclopentenes bearing an all carbon quaternary stereocenters in high yields with up to 30:1 dr and 99% ee. Moreover, a variety of highly enantioselective cascade hetero-Michael/ carbocyclizations were developed for the one-pot synthesis of valuable dihydrofurans and pyrrolidines (up to 98% ee) by using bench-stable heterogeneous Pd and chiral amines as co-catalysts. © 2012 Macmillan Publishers Limited. All rights reserved.

  • 26.
    Dellasala, D.A.
    et al.
    Geos Institute, 84-4th St., Ashland, OR 97420, United States.
    Fitzgerald, J
    1017 O St., NW, Washington, D.C. 20001, United States.
    Jonsson, Bengt Gunnar
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    McNeely, J
    International Union for Conservation of Nature (IUCN), 28 Rue Mauverney, 1196 Gland, Switzerland.
    Dovie, B
    School of Animal Plant and Environmental Sciences, Wits University, Wits 2050, South Africa.
    Dieterich, M
    Institute for Landscape and Vegetation Ecology (320), University of Hohenheim, D-70593 Stuttgart, Germany.
    Majluf, P
    Center for Environmental Sustainability, Cayetano Heredia University, Armendáriz 445, Lima 18, Peru.
    Nemtzov, S
    Israel Nature and Parks Authority, 3 Am Ve'Olamo Street, Jerusalem 95463, Israel.
    Nevin, O
    National School of Forestry, University of Cumbria, Penrith, CA11 0AH, United Kingdom.
    Parsons, E
    Department of Environmental Science and Policy, George Mason University, Fairfax, VA 22030, United States.
    Watson, J
    University of Queensland, Ecology Centre, Qld 4072, Australia.
    Priority Actions for Sustainable Forest Management in the International Year of Forests2012In: Conservation Biology, ISSN 0888-8892, E-ISSN 1523-1739, Vol. 26, no 3, p. 572-575Article in journal (Refereed)
  • 27.
    Duan, Ran
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Novel foamed materials from renewable sources2012In: 9th European Conference on Foams, Emulsions and Applications, 2012Conference paper (Refereed)
  • 28.
    Edvardsson, Sverker
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Gradin, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Isaksson, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Gulliksson, Mårten
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    A Note on Wet Paper Web Adhesion Strength2012In: Journal of Testing and Evaluation, ISSN 0090-3973, E-ISSN 1945-7553, Vol. 40, no 4, p. 682-686Article in journal (Refereed)
    Abstract [en]

    This work is concerned with the determination of the adhesion strength between a paper web and an adhesive surface. Edvardsson et al. [Edvardsson, S., Gradin, P., and Isaksson, P., "On Dissipative Effects of Paper Web Adhesion Strength," Int. J. Solids Struct., Vol. 48(1), 2011, pp. 24-30] suggested recently a model that takes into account the energy dissipation caused by elastic plastic deformation in the bent structure of a paper specimen. This model is further developed and investigated in the present work. A linear relation in plastic dissipation is discovered facilitating a novel analysis of the peeling tension and a more convenient determination of the proper adhesion strength. Industrial relevant examples are made with wet newsprint and kraft stock. A straightforward experimental procedure for determining the consistent adhesion strength is suggested. It is found that the agreement between the model and the experimental observations is good.

  • 29.
    Edvardsson, Sverker
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Gulliksson, Mårten
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Persson, Johan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    The dynamical functional particle method: an approach for boundary value problems2012In: Journal of applied mechanics, ISSN 0021-8936, E-ISSN 1528-9036, Vol. 79, no 2, p. art. no. 021012-Article in journal (Refereed)
    Abstract [en]

    The present work is concerned with new ideas of potential value for solving differential equations. First, a brief introduction to particle methods in mechanics is made by revisiting the vibrating string. The full case of nonlinear motion is studied and the corresponding nonlinear differential equations are derived. It is suggested that the particle origin of these equations is of more general interest than usually considered. A novel possibility to develop particle methods for solving differential equations in a direct way is investigated. The dynamical functional particle method (DFPM) is developed as a solution method for boundary value problems. DFPM is based on the concept of an interaction functional as a dynamical force field acting on quasi particles. The approach is not limited to linear equations. We exemplify by applying DFPM to several linear Schrödinger type of problems as well as a nonlinear case. It is seen that DFPM performs very well in comparison with some standard numerical libraries. In all cases, the convergence rates are exponential in time. © 2012 American Society of Mechanical Engineers.

  • 30.
    Ekelund, Nils
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Växter som kan simma2012In: Havsutsikt, ISSN 1104-0513, Vol. 1, no 1, p. 8-9Article in journal (Other (popular science, discussion, etc.))
  • 31.
    Erdegren, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Understanding surface defects on direct chill cast 6xxx aluminium billets2012Licentiate thesis, comprehensive summary (Other academic)
  • 32.
    Fernando, D.
    et al.
    Department of Forest Products/Wood Science, Wood Ultrastructure Research Centre (WURC), Swedish University of Agricultural Sciences, P.O. Box 7008, SE-750 07 Uppsala, Sweden.
    Muhic, D
    Holmen Paper AB, Braviken Mill, Norrköping, Sweden.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Daniel, G
    Department of Forest Products/Wood Science, Wood Ultrastructure Research Centre (WURC), Swedish University of Agricultural Sciences, P.O. Box 7008, SE-750 07 Uppsala, Sweden.
    Surface and internal micro/ultrastructure of TMP fibres produced during high-intensity refining elucidate the development of pulp and paper properties2012In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 66, no 4, p. 467-475Article in journal (Refereed)
    Abstract [en]

    Refining during mechanical pulping causes delamination and internal fibrillation (D/IF) of the fibre wall and changes the surface ultrastructure. Fundamental knowledge about these phenomena at the fibre cell wall level helps our understanding of the development of pulp and paper properties, which in turn facilitates the optimization of processes, helping to save energy and improve the characteristics of final products. In the present study, pulps were produced by double-disc (DD) refined thermomechanical processes (DD-TMP) and have been characterized at the fibre cell wall micro/ultrastructural level based on Fernando and Daniel’s method (2010) of Simons ’ staining and scanning electron microscopy (SEM). The pulps studied were never-dried Norway spruce DD-TMP from a full-scale mill trial running under different process conditions; a) varying refining intensity, achieved by using a high-intensity turbine segment (HTS) and a standard (Ref) segment from Metso, and b) varying specific energy consumption (SEC). Improved energy efficiency was obtained with HTS segments, giving adequate or better pulp properties with respect to elongation, light scattering, Canadian Standard Freeness (CSF) at a similar tensile index level and lower energy consumption. Energy efficiency was gained through an elevated degree of D/IF and S2 fibrillation with low energy input. Both the SEC and segment designs had a significant impact on elevating the degree of D/IF. Statistical evaluation of fibre development with respect to D/IF gave evidence for improved energy efficiency in HTS refining. Ultrastructural studies on fibre surfaces showed that HTS refining produced better external fibrillation and leads to exposing the secondary S2 wall as fibre outer layer with different ribbon-type S2 fibrillation. Information obtained at the fibre wall level concerning D/IF and surface ultrastructure contribute to the fundamental knowledge about the pulp and handsheet properties and the energy efficiency of TMP processing. Copyright © by Walter de Gruyter·Berlin·Boston.

  • 33.
    Ferritsius, Rita
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Reyier Österling, Sofia
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Ferritsius, Olof
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Development of TMP fibers in LC- and HC-refining2012In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, no 5, p. 860-871Article in journal (Refereed)
    Abstract [en]

    Low consistency (LC) refining and high consistency refining (HC) has been studied in a TMP mill. When strength properties were increased, the development of fiber properties was different in LC- and HC-refining. Fiber curl decreased in LC-refining but increased in HC-refining. LC-refining decreased fiber curl and increased tensile index simultaneously in this study. It is therefore likely that the decreased fiber curl contributes to the increase of tensile index in LC-refining. Furthermore, fiber wall thickness decreased and external fibrillation increased in HC-refining, while these properties were only slightly influenced in the LC-refining. Fibrillation was found to decrease in most cases for LC-refining while fiber wall thickness index increased slightly but consistently, which might indicate a less dense structure of the fiber wall or its surface layers. Double-disc HC-refining with the same energy input as in a conical single-disc refiner resulted in fibers of higher external fibrillation, lower fiber wall thickness and higher fiber curl at a given fiber length. The results indicate that analyzing individual fiber dimensions could be a better tool for understanding how fibers develop in different kinds of refining than analyzing conventional handsheet properties.

  • 34.
    Fjellström, Helena
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Htun, Myat
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Aspects of fibre wall swelling in high-yield pulp.2012In: PROCEEDING OF THE 4TH INTERNATIONAL CONFERENCE ON PULPING, PAPERMAKING AND BIOTECHNOLOGY (ICPPB '12), VOLS. I AND II, 2012, p. 1183-1186Conference paper (Refereed)
    Abstract [en]

    When producing mechanical pulps the fibre separation will take place in the weakest part of the wood matrix. A prerequisite to swelling in wood and mechanical pulps is that the wood matrix is softened. The position of where the weakest part of the wood matrix is situated can to a large extent be controlled by adjustment of the swelling and softening properties of each of the wood polymers (lignin, hemicelluloses and cellulose). Most probably the efficiency of the external and internal fibrillation of the fibre walls is also influenced by how the swelling and softening properties are controlled. The combination of position of fibre-fibre separation together with the efficiency of the external and internal fibrillation will to a large extent determine the energy demand to produce mechanical pulps. Refining of wood chips with different state of softening and swelling will give rise to fibres with different optical and physical properties. The most important parameters that influence the wood matrix and wood fibres’ ability to swell are temperature, pH, ionic form of and the amount of charged groups in the hemicelluloses and lignin of the cell walls. In order to improve the level of knowledge on how to influence the degree of wood matrix and fibre wall swelling of mechanical pulps we have undertaken to study the swelling properties of wood and fibres produced by means of different mechanical pulping processes.

    It was found that pulps not containing sulphonic acid groups need to be heated above the softening temperature of lignin in order to be able to swell to their full capacity. Introduction of sulphonic acid groups also opens up the rigid structure of lignin which lowers the softening temperature and increases the swelling potential even at lower temperatures. The effect of valence of the counter ion was also shown to be more pronounced after adding more carboxylic acid groups to a pulp. Depending on the number and type of anionic acid groups in the fibres, high-yield pulps will have different combinations of properties in different ionic conditions. The preliminary conclusions from this study are that the ability to control swelling properties of mechanical pulps is an important feature to take into account when producing pulp and paper.

  • 35.
    Gorski, Dmitri
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Hill, Jan
    QualTech AB (Previously Norske Skog ASA), SE-282 21, Tyringe, Sweden.
    Improved quality of SC magazine paper through enhanced fibre development using the ATMP process2012In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, no 1, p. 35-41Article in journal (Refereed)
    Abstract [en]

    A pilot scale refining trial was conducted using the ATMP (Advanced Thermomechanical Pulp) refining concept with White spruce as raw material. Low-intensity TMP and high-intensity TMP with mechanical pre-treatment of chips were compared to ATMP (Mg+P), where development of fibres was enhanced using hydrogen peroxide and magnesium hydroxide. The main goal of the trial was to evaluate the potential of using ATMP process for production of SC (supercalendered) magazine paper. SC paper is especially demanding when it comes to the paper surface structure which is strongly influenced by the development of fibre properties.

    Improvement in individual fibre properties such as flexibility, fibre split index and fibre surface area index achieved using ATMP process was found to translate into decreased surface roughness and air permeability of calendered laboratory sheets. Both the refining process configuration and the addition of process chemicals were found to have significant impacts though the process configuration had major role. The influence of process chemicals on PPS was mainly pronounced after second stage refining. The magnitude of surface roughening (fibre rising) was found to be influenced mainly by the process configuration.

  • 36.
    Gorski, Dmitri
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Johansson, L
    Paper and Fibre Research Institute (PFI), Trondheim, Norway.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Refiner bleaching in a peroxide-based ATMP process compared with conventional bleaching2012In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 66, no 3, p. 275-281Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to compare refiner bleaching with conventional laboratory bleaching by means of hydrogen peroxide and magnesium hydroxide. Refiner bleaching in this study was a part of the ATMP (advanced thermo mechanical pulping) process, in which bleaching chemicals are added to the first stage refiner. Unbleached reference pulp which underwent similar mechanical treatment as refiner bleached pulp was used for laboratory bleaching. Bleaching efficiency was found to be almost equal for pilot scale refiner bleaching and conventional laboratory bleaching. A brightness increase of 10 ISO was reached with addition of 26 kg t -1 hydrogen peroxide leading to a final brightness of 66 ISO using both methods. Slightly more COD (52kg t -1 compared with 46 kg t -1) was generated in refiner bleaching compared with conventional laboratory bleaching to equal brightness with the same chemicals added. © 2012 by Walter de Gruyter Berlin Boston 2012.

  • 37.
    Granberg, Hjalmar
    et al.
    Innventia AB.
    Gustafsson Coppel, Ludovic
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Eita, M.
    Innventia AB, Box 5604, 104 86 Stockholm, Sweden.
    de Mayolo, E. A.
    Innventia AB, Box 5604, 104 86 Stockholm, Sweden.
    Arwin, Hans
    Innventia AB, Box 5604, 104 86 Stockholm, Sweden.
    Wågberg, Lars
    Innventia AB, Box 5604, 104 86 Stockholm, Sweden.
    Dynamics of moisture interaction with polyelectrolyte multilayers containing nanofibrillated cellulose2012In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, no 2, p. 496-499Article in journal (Refereed)
    Abstract [en]

    Recent findings have shown that it is possible to use the Layer-by-Layer technique to create nanofibrillated cellulose / polyethyleneimine interference films whose colour change with relative humidity. This study uses different optical models to describe spectral ellipsometry measurements data of interference films and how the film properties alter in dry and humid environments. The results indicate that water condensation initially is filling the surface pores within seconds whereas relaxation of the film to adjust to the added water is a slower process that reaches a steady state after ≈20 min. The maximum swelling ratio of the LbL films is almost independent of the number of layers within the film, but decreases considerably by crosslinking via heat treatment. The films show a distinct birefringence with optical axis perpendicular to the surface. Analysis of the moisture response with different optical models indicates that the films swell uniformly in the thickness direction with no separate water film on top. The results provide important understanding for the design of NFC based LbL films for visual moisture sensors and interactive security paper. 

  • 38.
    Gulliksson, Mårten
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Edvardsson, Sverker
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Lind, Andreas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    The dynamical functional method2012Other (Other academic)
  • 39.
    Gustafsson Coppel, Ludovic
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Whiteness and Fluorescence in Layered Paper and Board: Perception and Optical Modelling2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is about modelling and predicting the perceived whiteness of plain paper from the paper composition, including fluorescent whitening agents. This involves psychophysical modelling of perceived whiteness from measurable light reflectance properties, and physical modelling of light scattering and fluorescence from the paper composition.

    Existing models are first tested and improvements are suggested and evaluated. A colour appearance model including simultaneous contrast effects (CIECAM02-m2), earlier tested on coloured surfaces, is successfully applied to perceived whiteness. An extension of the Kubelka-Munk light scattering model including fluorescence for turbid media of finite thickness is successfully tested for the first time on real papers. It is extended to layered constructions with different layer optical properties and modified to enable parameter estimation with conventional d/0° spectrophotometers used in the paper industry. Lateral light scattering is studied to enable simulating the spatially resolved radiance factor from layered constructions, and angle-resolved radiance factor simulations are performed to study angular variation of whiteness.

    It is shown that the linear CIE whiteness equation fails to predict the perceived whiteness of highly white papers with distinct bluish tint. This equation is applicable only in a defined region of the colour space, a condition that is shown to be not fulfilled by many commercial office papers, although they appear white to most observers. The proposed non-linear whiteness equations give to these papers a whiteness value that correlates with their perceived whiteness, while application of the CIE whiteness equation outside its region of validity overestimates perceived whiteness.

    It is shown that the fluorescence efficiency of FWA is essentially dependent only on the ability of the FWA to absorb light in its absorption band. Increased FWA concentration leads accordingly to increased whiteness. However, since FWA absorbs light in the violet-blue region of the electromagnetic spectrum, the reflectance factor decreases in that region with increasing FWA amount. This violet-blue absorption tends to give a greener shade to the paper and explains most of the observed greening and whiteness saturation at larger FWA concentrations. A red-ward shift of the quantum efficiency is observed with increasing FWA concentration, but this is shown to have a negligible effect on the whiteness value. The results are directly applicable to industrial applications for better instrumental measurement of whiteness and thereby optimising the use of FWA with the goal to improve the perceived whiteness.

  • 40.
    Gustafsson Coppel, Ludovic
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Andersson, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Neuman, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Edström, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Fluorescence model for multi-layer papers using conventional spectrophotometers2012In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, no 2, p. 418-425Article in journal (Refereed)
    Abstract [en]

    We present an extension of a Kubelka-Munk based fluorescence model in which we introduce an apparent scattering (SUV) and absorption (KUV) coefficient for all wavelengths below 400 nm. We describe a method for modelling the total radiance factor of multi-layer papers and for estimating the optical parameters (S, K and Q) of each layer. Assuming that the fluorescent whitening agent only absorbs below 400 nm, we are able to determine SUV, KUV and the apparent quantum efficiency, Q(UV,l) for 400 nm<l<700 nm, from spectral radiance measurements in the visual part of the electromagnetic spectrum. We test the proposed method on different layered constructions made of three individual pilot paper layers. The proposed method allows the papermaker to determine the illumination independent fluorescence characteristics of single- and multilayer paper layers using a conventional single-monochromator spectrophotometer operating in the visible part of the electromagnetic spectrum, and also to predict the radiance factor of fluorescing layered papers.

  • 41.
    Gustafsson Coppel, Ludovic
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Neuman, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Edström, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Extension of the Stokes equation for layered constructions to fluorescent turbid media2012In: Journal of the Optical Society of America A, ISSN 1084-7529, Vol. 29, no 4, p. 574-578Article in journal (Refereed)
    Abstract [en]

    Expressions relating the bispectral reflectance of a stack of n fluorescinglayers to each individual layer's reflectance and transmittance arederived. This theoretical framework is used together with recentlyproposed extensions of the Kubelka--Munk model to study the fluorescencefrom layered turbid media. For one layer over a reflecting background,the model is shown to give the same results as a previous model.The extension to n layers with different optical properties allowssimulating the bispectral reflectance from a pad of layered turbidmedia. The applicability of the model is exemplified with an optimizationof fluorophore distribution in layered turbid media.

  • 42. Gustafsson, John
    et al.
    Hummelgård, Christine
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Bäckström, Joakim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Odnevall Wallinder, Inger
    Habibur Rahman, Seikh Muhammad
    Lindbergh, Göran
    Eriksson, Sten
    Cornell, Ann
    In-situ activated hydrogen evolution by molybdate addition to neutral and alkaline electrolytes2012In: Journal of electrochemical science and engineering, ISSN 1847-9286, Vol. 2, no 3, p. 105-120Article in journal (Refereed)
    Abstract [en]

    Activation of the hydrogen evolution reaction (HER) by in-situ addition of Mo(VI) to the electrolyte has been studied in alkaline and pH neutral electrolytes, the latter with the chlorate process in focus. Catalytic molybdenum containing films formed on the cathodes during polarization were investigated using scanning electron microscopy (SEM), energy-dispersive X ray analysis (EDS), X-ray photoelectron spectroscopy (XPS), and X ray fluorescence (XRF). In-situ addition of Mo(VI) activates the HER on titanium in both alkaline and neutral electrolytes and makes the reaction kinetics independent of the substrate material. Films formed in neutral electrolyte consisted of molybdenum oxides and contained more molybdenum than those formed in alkaline solution. Films formed in neutral electrolyte in the presence of phosphate buffer activated the HER, but were too thin to be detected by EDS. Since molybdenum oxides are generally not stable in strongly alkaline electrolyte, films formed in alkaline electrolyte were thinner and probably co-deposited with iron. A cast iron molybdenum alloy was also investigated with respect to activity for HER. When polished in the same way as iron, the alloy displayed a similar activity for HER as pure iron.

  • 43. Gustafsson, John
    et al.
    Li, Gongzhuo
    Hummelgård, Christine
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Bäckström, Joakim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Cornell, Ann
    On the suppression of cathodic hypochlorite reduction by electrolyte additions of molybdate and chromate ions2012In: Journal of electrochemical science and engineering, ISSN 1847-9286, Vol. 2, no 4, p. 185-198Article in journal (Refereed)
    Abstract [en]

    The goal of this study was to gain a better understanding of the feasibility of replacing Cr(VI) in the chlorate process by Mo(VI), focusing on the cathode reaction selectivity for hydrogen evolution on steel and titanium in a hypochlorite containing electrolyte. To evaluate the ability of Cr(VI) and Mo(VI) additions to hinder hypochlorite reduction, potential sweep experiments on rotating disc electrodes and cathodic current efficiency (CE) measurements on stationary electrodes were performed. Formed electrode films were investigated with scanning electron microscopy and energy-dispersive X-ray spectroscopy. Cathodic hypochlorite reduction is hindered by the Mo-containing films formed on the cathode surface after Mo(VI) addition to the electrolyte, but much less efficient compared to Cr(VI) addition. Very low levels of Cr(VI), in the mM range, can efficiently suppress hypochlorite reduction on polished titanium and steel. Phosphate does not negatively influence the CE in the presence of Cr(VI) or Mo(VI) but the Mo-containing cathode films become thinner if the electrolyte during the film build-up also contains phosphate. For a RuO2-TiO2 anode polarized in electrolyte with 40 mM Mo(VI), the anode potential increased and increased molybdenum levels were detected on the electrode surface

  • 44.
    Göransson, Kristina
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Söderlind, Ulf
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Tar/CH4 Reforming by Catalytic Bed Materials in a Biomass Fluidised Bed Gasifier2012In: 20th European Biomass Conference & Exhibition: Proceedings of the International Confernce held in Milano, Italy, 18 - 22 June 2012, 2012Conference paper (Other academic)
    Abstract [en]

    A study on in-bed catalytic material reforming of tar/methane (CH4) has been performed in the 150 kW allothermal biomass gasifier at Mid Sweden University (MIUN). The MIUN gasifier, built for research on synthetic fuel production, is a dual fluidised bed gasifier (DFBG). The syngas for automotive fuels synthesis has a strict specification of impurities. The biggest challenge for biomass fluidised-bed gasification is the reforming of tars and CH4. Internal reforming should be considered before downstream reforming. The MIUN gasifier has a unique design suitable for in-bed tar/CH4 catalytic reforming and continuously internal regeneration of the reactive bed material. The experimental tests are carried out in three cases: 1) basic condition with silica sand (no catalytic activity), 2) calcinated olivine, and 3) Fe-impregnated olivine (10%wtFe/Olivine Catalyst). The measurement results have been evaluated by comparing tar/CH4 content in the syngas from the gasifier operated under different operation conditions. These results in BFB mode have initiated the ongoing investigations of the catalytic effects and regeneration in DFB mode. It can be concluded that the Fe-impregnated olivine showed a surprising low reactivity for tar and CH4 reforming in the BFB model. 

  • 45.
    Hagström, Å.K.
    et al.
    Pheromone group, Department of Biology, Lund University, Lund, Sweden.
    Liénard, M
    Pheromone group, Department of Biology, Lund University, Lund, Sweden.
    Groot, A
    Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Löfstedt, C
    Pheromone group, Department of Biology, Lund University, Lund, Sweden.
    Semi-selective fatty acyl reductases from four heliothine moths influence the specific pheromone composition2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 5, p. Art. no. e37230-Article in journal (Refereed)
    Abstract [en]

    Background: Sex pheromones are essential in moth mate communication. Information on pheromone biosynthetic genes and enzymes is needed to comprehend the mechanisms that contribute to specificity of pheromone signals. Most heliothine moths use sex pheromones with (Z)-11-hexadecenal as the major component in combination with minor fatty aldehydes and alcohols. In this study we focus on four closely related species, Heliothis virescens, Heliothis subflexa, Helicoverpa armigera and Helicoverpa assulta, which use (Z)-11-hexadecenal, (Z)-9-tetradecanal, and (Z)-9-hexadecenal in different ratios in their pheromone blend. The components are produced from saturated fatty acid precursors by desaturation, β-oxidation, reduction and oxidation. Results: We analyzed the composition of fatty acyl pheromone precursors and correlated it to the pheromone composition. Next, we investigated whether the downstream fatty-acyl reduction step modulates the ratio of alcohol intermediates before the final oxidation step. By isolating and functionally characterizing the Fatty Acyl Reductase (pgFAR) from each species we found that the pgFARs were active on a broad set of C8 to C16 fatty acyl substrates including the key pheromone precursors, Z9-14, Z9-16 and Z11-16:acyls. When presenting the three precursors in equal ratios to yeast cultures expressing any of the four pgFARs, all reduced (Z)-9-tetradecenoate preferentially over (Z)-11-hexadecenoate, and the latter over (Z)-9-hexadecenoate. Finally, when manipulating the precursor ratios in vitro, we found that the pgFARs display small differences in the biochemical activity on various substrates. Conclusions: We conclude that a pgFAR with broad specificity is involved in heliothine moth pheromone biosynthesis, functioning as a semi-selective funnel that produces species-specific alcohol product ratios depending on the fatty-acyl precursor ratio in the pheromone gland. This study further supports the key role of these in pheromone biosynthesis and emphasizes the interplay between the pheromone fatty acyl precursors and the Lepidoptera specific pgFARs in shaping the pheromone composition. © 2012 Hagström et al.

  • 46.
    He, Jie
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    GASIFICATION-BASED BIOREFINERY FOR MECHANICAL PULP MILLS2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The modern concept of "biorefinery" is dominantly based on chemical pulp mills to create more value than cellulose pulp fibres, and energy from the dissolved lignins and hemicelluloses. This concept is characterized by the conversion of biomass into various biobased products. It includes thermochemical processes such as gasification and fast pyrolysis. In mechanical pulp mills, the feedstock available to the gasification-based biorefinery is significant, including logging residues, bark, fibre material rejects, biosludges and other available fuels such as peat, recycled wood, and paper products. This work is to study co-production of bio-automotive fuels, biopower, and steam via gasification in the context of the mechanical pulp industry.

     

    Biomass gasification with steam in a dual-fluidized bed gasifier (DFBG) was simulated with ASPEN Plus. From the model, the yield and composition of the syngas and the contents of tar and char can be calculated. The model has been evaluated against the experimental results measured on a 150 KWth Mid Sweden University (MIUN) DFBG. The model predicts that the content of char transferred from the gasifier to the combustor decreases from 22.5 wt.% of the dry and ash-free biomass at gasification temperature 750 ℃ to 11.5 wt.% at 950 ℃, but is insensitive to the mass ratio of steam to biomass (S/B). The H2 concentration is higher than that of CO under normal DFBG operating conditions, but they will change positions when the gasification temperature is too high above about 950 ℃, or the S/B ratio is too far below about 0.15. The biomass moisture content is a key parameter for a DFBG to be operated and maintained at a high gasification temperature. The model suggests that it is difficult to keep the gasification temperature above 850 ℃ when the biomass moisture content is higher than 15.0 wt.%. Thus, a certain amount of biomass needs to be added in the combustor to provide sufficient heat for biomass devolatilization and steam reforming. Tar content in the syngas can also be predicted from the model, which shows a decreasing trend of the tar with the gasification temperature and the S/B ratio. The tar content in the syngas decreases significantly with gasification residence time which is a key parameter.

     

    Mechanical pulping processes, as Thermomechanical pulp (TMP), Groundwood (SGW and PGW), and Chemithermomechanical pulp (CTMP) processes have very high wood-to-pulp yields. Producing pulp products by means of these processes is a prerequisite for the production of printing paper and paperboard products due especially to their important functional properties such as printability and stiffness. However, mechanical pulping processes consume a great amount of electricity, which may account for up to 40% of the total pulp production cost. In mechanical pulping mills, wood (biomass) residues are commonly utilized for electricity production through an associated combined heat and power (CHP) plant. This techno-economic evaluation deals with the possibility of utilizing a biomass integrated gasification combined cycle (BIGCC) plant in place of the CHP plant. Integration of a BIGCC plant into a mechanical pulp production line might greatly improve the overall energy efficiency and cost-effectiveness, especially when the flow of biomass (such as branches and tree tops) from the forest is increased. When the fibre material that negatively affects pulp properties is utilized as a bioenergy resource, the overall efficiency of the system is further improved. A TMP+BIGCC mathematic model is developed based on ASPEN Plus. By means of this model, three cases are studied:

     

    1) adding more forest biomass logging residues in the gasifier,

    2) adding a reject fraction of low quality pulp fibers to the gasifier, and

    3) decreasing the TMP-specific electricity consumption (SEC) by up to 50%.

     

    For the TMP+BIGCC mill, the energy supply and consumption are analyzed in comparison with a TMP+CHP mill. The production profit and the internal rate of return (IRR) are calculated. The results quantify the economic benefit from the TMP+BIGCC mill.

     

    Bio-ethanol has received considerable attention as a basic chemical and fuel additive. It is currently produced from sugar/starch materials, but can also be produced from lignocellulosic biomass via a hydrolysis--fermentation or thermo-chemical route. In terms of the thermo-chemical route, a few pilot plants ranging from 0.3 to 67 MW have been built and operated for alcohols synthesis. However, commercial success has not been achieved. In order to realize cost-competitive commercial ethanol production from lignocellulosic biomass through a thermo-chemical pathway, a techno-economic analysis needs to be done.

     

    In this work, a thermo-chemical process is designed, simulated, and optimized mainly with ASPEN Plus. The techno-economic assessment is made in terms of ethanol yield, synthesis selectivity, carbon and CO conversion efficiencies, and ethanol production cost.

     

    Calculated results show that major contributions to the production cost are from biomass feedstock and syngas cleaning. A biomass-to-ethanol plant should be built at around 200 MW. Cost-competitive ethanol production can be realized with efficient equipments, optimized operation, cost-effective syngas cleaning technology, inexpensive raw material with low pretreatment cost, high-performance catalysts, off-gas and methanol recycling, optimal systematic configuration and heat integration, and a high-value byproduct.

  • 47.
    He, Jie
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Göransson, Kristina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Söderlind, Ulf
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Simulation of biomass gasification in a dual fluidized bed gasifier2012In: Biomass Conversion and Biorefinery, ISSN 2190-6815, E-ISSN 2190-6823, Vol. 2, no 1, p. 1-10Article in journal (Refereed)
  • 48.
    Heintze, Katarzyna
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Lake phytoplankton quantification bychlorophyll a, comparative study ofspectrophotometry and FluoroProbe: Including physical and chemical parameters of water2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 49.
    Hellström, Lisbeth
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Carlberg, Torbjörn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Gradin, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Gregersen, Øyvind
    Department for Chemical Engineering, NTNU, Norway.
    Evaluation Of Collimated Chipping Technology For Reducing Energy Consumption In Mechanical Pulping2012In: Journal of Science & Technology for Forest Products and Processes, ISSN 1927-6311, E-ISSN 1927-632X, Vol. 2, no 3, p. 6-9Article in journal (Refereed)
    Abstract [en]

    It has recently been shown that the energy efficiency during first-stage TMP (thermo-mechanical pulp) refining can be improved using amodified chipping method (collimated chipping), where the angle between the fibre direction of the wood specimen and the cutting plane is increased. This paper reports the differences in properties of TMP refined from wood chips produced at two different spout angles, 30° and 50°, with and without the addition of sodium bisulphite (NaHSO3) to the dilution water. It was found that the specific energy input for a certain CSF (Canadian Standard Freeness) value was lower for chips produced at spout 50°, but that the addition of chemicals to the dilution water had no influence on the specific energy value for a given CSF value. However, the tensile index and specific light-scattering coefficient were substantially higher for handsheets made from the pulp refined from chips produced at spout angle 50° and with NaHSO3 added compared to handsheets from pulp made from 30° and 50° chips without chemicals added.

  • 50.
    Hummelgård, Christine
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Nanoscaled Structures of Chlorate Producing Electrodes2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Sodium chlorate is mainly used for production of chlorine dioxide (a pulp bleaching agent). Sodium chlorate is produced by an electrochemical process where chloride ions (from sodium chloride dissolved in water) are oxidized to chlorine on the anodes and hydrogen is evolved on the cathodes. The anode of this process consists of a metal plate coated with a catalytically active metal oxide film. The electrocatalytic properties of the anode coating film have been widely investigated due to the great importance of these electrodes in the electrochemical industry. The material properties are, however, not as well investigated, and the studies described in this thesis are an attempt to remedy this.

    Several standard material characterization methods were used, such as SEM, TEM, AFM, EDX, XRD, porosimetry and DSC. Also, a novel model system based on spin coated electrode films on smooth substrates was developed. The model system provided a way to design samples suitable for e.g. TEM, where the sample thickness is limited to maximum of 100 nm. This is possible due to the ability to control the film thickness by the spinning velocity when using the spin coating technique.

    It was shown here that the anode coating has a nanostructure. It consists of grains, a few tens of nanometers across. The nanostructure leads to a large effective area and thus provides an explanation of the superior catalytic properties of these coatings. The grains were also shown to be monocrystalline. The size of these grains and its origin was investigated. The calcination temperature, the precursor salt and (if any) doping material all affected the grain size. A higher calcination temperature yielded larger grains and doping with cobalt resulted in smaller grains and therefore a larger real area of the coating. Some preparation conditions also affected the microstructure of the coating; such as substrate roughness. The microstructure is for example the cracked-mud structure. A smoother substrate gave a lower crack density.

    The cathode of chlorate production is usually an uncoated metal plate, therefore 'less catalytically active'. It is, however, possible to activate the cathode by for example in situ additions to the electrolyte. It was shown here that sufficient addition of molybdate to the electrolyte resulted in a molybdenum film deposited on the cathode and thereby an increase of its surface area and an activation the hydrogen evolution reaction.

123 1 - 50 of 119
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf