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  • 101.
    Christenson, Nina
    et al.
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Department of Geography, Media and Communication.
    Chang Rundgren, Shu-Nu
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Zeidler, Dana
    University of South Florida, USA.
    The Relationship of Discipline Background to Upper Secondary Students´ Argumentation on Socioscientific Issues2014In: Research in science education, ISSN 0157-244X, E-ISSN 1573-1898, Vol. 44, no 4, p. 581-601Article in journal (Refereed)
    Abstract [en]

    In the present STEM (Science, Technology, Engineering, and Mathematics)-driven society, socioscientific issues (SSI) have become a focus globally and SSI research has grown into an important area of study in science education. Since students attending the social and science programs have a different focus in their studies and research has shown that students attending a science program are less familiar with argumentation practice, we make a comparison of the supporting reasons social science and science majors use in arguing different SSI with the goal to provide important information for pedagogical decisions about curriculum and instruction. As an analytical framework, a model termed SEE-SEP covering three aspects (of knowledge, value, and experiences) and six subject areas (of sociology/culture, economy, environment/ecology, science, ethics/morality, and policy) was adopted to analyze students’ justifications. A total of 208 upper secondary students (105 social science majors and 103 science majors) from Sweden were invited to justify and expound their arguments on four SSI including global warming, genetically modified organisms (GMO), nuclear power, and consumer consumption. The results showed that the social science majors generated more justifications than the science majors, the aspect of value was used most in students’ argumentation regardless of students’ discipline background, and justifications from the subject area of science were most often presented in nuclear power and GMO issues. We conclude by arguing that engaging teachers from different subjects to cooperate when teaching argumentation on SSI could be of great value and provide students from both social science and science programs the best possible conditions in which to develop argumentation skills.

  • 102.
    Christenson, Nina
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences. Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Department of Geography, Media and Communication.
    Rundgren, Shu-Nu Chang
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    A Framework for Teachers’ Assessment of Socio-scientific Argumentation: An example using the GMO issue2014In: Journal of Biological Education, ISSN 0021-9266, E-ISSN 2157-6009, no 2, p. 204-212Article in journal (Refereed)
    Abstract [en]

    Socio-scientific issues (SSI) have proven to be suitable contexts for students to actively reflect on and argue about complex social issues related to science. Research has indicated that explicitly teaching SSI argumentation is a good way to help students develop their argumentation skills and make them aware of the complexity of SSI. However, assessing the quality of students’ arguments on SSI is evidently difficult for many teachers. This article aims to facilitate teachers’ assessment of the quality of students’ arguments on SSI by introducing a new assessment framework that represents a low degree of complexity and exemplifying it by applying it to students’ written SSI argumentation concerning genetically modified organisms (GMO). The new assessment framework considers both the quality indicators presented in the research literature and curricular guidelines for the science courses in Swedish secondary and upper secondary school. The framework focuses on both the content and the structure that can be revealed in students’ SSI argumentation and is meant to function as a tool for identifying quality indicators that could serve as the basis for grading.

  • 103.
    Christophliemk, Hanna
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Johansson, Caisa
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Ullsten, Henrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Järnström, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Oxygen and water vapor transmission rates of starch-poly(vinyl alcohol) barrier coatings for flexible packaging paper2017In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 113, p. 218-224Article in journal (Refereed)
    Abstract [en]

    Creating efficient water-borne dispersions based mainly on renewable materials for coating of flexible packaging paper was the aim of this study. The effects of an ethylene modified poly(vinyl alcohol) grade and a standard poly(vinyl alcohol) on the oxygen and water vapor barrier performance of corn starch and potato starch coatings was studied. The results showed that a coating composition with a high fraction of a renewable polymer was effective in keeping the oxygen barrier at a technically and commercially applicable level. An ethylene modified poly(vinyl alcohol) grade was found to provide lower oxygen transmission rates at high relative humidity, as compared to a standard poly(vinyl alcohol) grade. The oxygen barrier properties of blends of starch and poly (vinyl alcohol) were similar to that of the pure modified poly(vinyl alcohol) in the range from 0% starch to 60% starch. This was observed with both hydroxypropylated and octenyl succinate modified starch grades. The drying conditions of the mixed starch:poly(vinyl alcohol) coatings were based on drying trials with pure poly (vinyl alcohol) coatings. Drying at moderate temperatures indicated the possibility to slightly decrease water vapor transmission rate by higher drying temperature. Several secondary effects of increased drying temperature such as coating hold-out and formation of defects may also be of importance.

  • 104.
    Christophliemk, Hanna
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Jokela, Jukka
    Christophliemk, Mika
    Kuokkanen, Toivo
    Study of Organic Coagulants and Flocculants in the Waste Water Treatment2007Conference paper (Other academic)
  • 105.
    Christophliemk, Hanna
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Koskinen, Ari M.P.
    An Improved Synthesis of the C1-C9 -fragment of Calyculin C.1997Conference paper (Other academic)
  • 106.
    Christophliemk, Hanna
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Ullsten, Henrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Johansson, Caisa
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences, Paper Surface Centre.
    Järnström, Lars
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science.
    Exploiting the synergies between starch, nanoclay and other additives to enhance the barrier properties of paper; Starch coatings - striking balance between the benefits and the drawbacks2011Conference paper (Other academic)
  • 107.
    Christophliemk, Hanna
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Ullsten, Henrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Johansson, Caisa
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Järnström, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Starch-poly(vinyl alcohol) barrier coatings for flexible packaging paper and their effects of phase interactions2017In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 111, p. 13-22Article in journal (Refereed)
    Abstract [en]

    Starch and poly(vinyl alcohol) based barrier coatings for flexible packaging papers were studied. Both octenyl succinate modified and hydroxypropylated corn and potato starches were blended with regular and ethylene modified poly(vinyl alcohol) to increase the water vapor barrier properties and enhance the flexibility of the starch coatings, in order to accomplish superior barrier performance. Phase separation between starch and poly (vinyl alcohol) was studied in detail, both in the solution and in dry draw-down coatings on paper. The barrier performance of the coated paper was evaluated with respect to water vapor transmission rate. Conditions for the creation of a thin surface layer consisting of only one of the pure polymers were identified and discussed in terms of phase separation in solution migration of poly(vinyl alcohol) to the uppermost surface layer. The phase separation promoted low water vapor transmission rates also with a rather high fraction of starch in the coatings

  • 108.
    Cilpa-Karhu, Geraldine
    et al.
    Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki.
    Lipponen, Katriina
    Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki.
    Samuelsson, Jörgen
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Ööri, Katariina
    Wihuri Research Institute, FIN-00290 Helsinki, Finland.
    Fornstedt, Torgny
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Riekkola, Marja-Liisa
    Chemistry, Department of Chemistry, University of Helsinki.
    Three complementary techniques for the clarification of temperature effect on low-density lipoprotein–chondroitin-6-sulfate interaction2013In: Analytical Biochemistry, ISSN 0003-2697, E-ISSN 1096-0309, Vol. 443, no 2, p. 139-147Article in journal (Refereed)
    Abstract [en]

    Abstract A rigorous processing of adsorption data from quartz crystal microbalance technology was successfully combined with the data obtained by partial filling affinity capillary electrophoresis and molecular dynamics for the clarification of the temperature effect on the interaction of a major glycosaminoglycan chain chondroitin-6-sulfate (C6S) of proteoglycans with low-density lipoprotein (LDL) and with a peptide fragment of apolipoprotein B-100 (residues 3359–3377 of LDL, PPBS). Two experimental techniques and computational atomistic methods demonstrated a nonlinear pattern of the affinity of C6S at temperatures above 38.0 °C to both LDL and PPBS. The temperature affects the interaction of C6S with LDL and PPBS by influencing the structural behavior of glycosaminoglycan C6S and/or that of LDL.

  • 109.
    Cirillo, Emilio N.M.
    et al.
    Sapienza Universit`a di Roma, Italy.
    Colangeli, Matteo
    Moons, Ellen
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Physics (from 2013).
    Muntean, Adrian
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Muntean, Stela Andrea
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Physics (from 2013).
    van Stam, Jan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    A lattice model approach to the morphology formation from ternary mixtures during the evaporation of one component2019In: The European Physical Journal Special Topics, ISSN 1951-6355, E-ISSN 1951-6401, Vol. 228, no 1, p. 55-68Article in journal (Refereed)
    Abstract [en]

    Stimulated by experimental evidence in the field of solution-born thin films, we study the morphology formation in a three state lattice system subjected to the evaporation of one component. The practical problem that we address is the understanding of the parameters that govern morphology formation from a ternary mixture upon evaporation, as is the case in the fabrication of thin films from solution for organic photovoltaics. We use, as a tool, a generalized version of the Potts and Blume-Capel models in 2D, with the Monte Carlo Kawasaki-Metropolis algorithm, to simulate the phase behaviour of a ternary mixture upon evaporation of one of its components. The components with spin 1, −1 and 0 in the Blume-Capel dynamics correspond to the electron-acceptor, electron-donor and solvent molecules, respectively, in a ternary mixture used in the preparation of the active layer films in an organic solar cell. Furthermore, we introduce parameters that account for the relative composition of the mixture, temperature, and interaction between the species in the system. We identify the parameter regions that are prone to facilitate the phase separation. Furthermore, we study qualitatively the types of formed configurations. We show that even a relatively simple model, as the present one, can generate key morphological features, similar to those observed in experiments, which proves the method valuable for the study of complex systems.

  • 110.
    Corrigox, Adam
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Energianalys av rörledning med överhettad vattenånga2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Heat transfer is an important physical phenomenon with many different industrial applications, where the transport of a fluid in a pipe is an important part. The main mechanism of heat transfer in flowing or stagnant fluids is convection. A better knowledge and understanding of the underlying physics would imply that the design of the systems could be optimized in order to obtain an economic process by minimizing energy losses and cost of materials.

    A steam turbine in a power plant produces electricity by superheated steam flowing through the turbine. The superheated steam is then transported from the turbine into a pipeline to be used for heating processes in a nearby pulp mill. In this work, an energy analysis was carried out on the pipeline with superheated steam in order to determine the temperature distribution. The choice of material in the pipeline is dependent on pressure and temperature, and with a lack of knowledge of the temperature distribution along the pipe, the construction could be unnecessarily costly.

    A mathematical model was set up with the energy balances acting on the pipeline. An analytical calculation was carried out to analyze how much the heat loss from the pipe is and how much the temperature of the steam decreases. A dynamic model was then built in Simulink to simulate the accumulation of heat in the pipe and the insulation over time, and the mass flow of cooling water. A literature study of the vaporization of the cooling water was carried out to find the parameters that affect evaporation and thus is important in determining the time it takes until all have vaporized.

    The results of the calculations show that the temperature drop of the superheated steam in the flow direction becomes very small. This is because the energy content of the flowing steam is very large compared to the heat loss through the pipe wall. The result from the dynamic simulation shows that the insulation has a larger time constant compared to steel pipe. This is presented in the form of the step response.

    The choice of material will be affected by the position of the desuperheater. In this system the desuperheater is not optimally placed since it is about 42 m after the inlet of the turbine. It would therefore be possible to place it closer to the turbine and then switch to a cheaper lower strength material. 

  • 111.
    Dahlin, Per
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Na/S balances at Skoghall mill 2015: Balances after reconstruction of the fiber line2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The scope of this master thesis was to investigate how a reconstruction at Skoghall Mill had changed the Na/S balance as well as evaluating how a new chemical plant manufacturing the mill’s chlorine dioxide would affect the balance. This was done by analyzing ingoing and outgoing process streams at the mill for sodium and sulfur and using obtained flow data for the period after the reconstruction. A balance was made to simulate how the system behaved at the time as well as balances simulating different shares of bleached pulp being manufactured. Balances with three possible types of chemical plants were also made, as well as calculations of the operating cost for each type of plant. From the balances and the operating costs it was concluded that the HPA process was the most beneficial for the Na/S balance as well as having the lowest operating cost.

  • 112.
    Dahlén, Pär
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Underlag till en standard för teknisk isolering2014Independent thesis Basic level (professional degree), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Vid upphandling inom offentlig sektor eller större företag kan användandet av standarder vara ett viktigt redskap för att säkerställa att en produkt eller tjänst uppfyller de krav som verksamheten ställer när det gäller exempelvis kvalitet, kostnader och effekter på miljön. Stigande priser på energi och en ökad insikt om samhällets negativa inverkan på miljön gör att energieffektiviseringar blivit ett viktigt inslag i de allra flesta verksamheter och här kan användandet av standarder spela en viktig roll.Syftet med det här examensarbetet är att utreda hur isolering av varma och kalla rör samt ventilationskanaler kan dimensioneras optimalt så att energiförluster från dessa minimeras. Hur olika faktorer och förutsättningar påverkar vad som är en optimerad isolering måste därmed även att utredas så att konsekvenser av olika val kan kartläggas.Målet är att ta fram ett underlag som kan fungera som hjälpmedel då en ny standard för dimensionering av teknisk isolering skall tas fram av Landstingsfastigheter i Värmland. Underlaget kommer att utgöras av en beräkningsmodell som skall kunna ge tillförlitliga uppgifter om hur olika yttre faktorer samt val av isoleringsmaterial dels kan påverka vilken den nödvändiga isoleringstjockleken blir och dels visa de ekonomiska konsekvenserna. En livscykelkostnadsanalys gjordes därför för olika dimensioneringsalternativ.Arbetet resulterade i en beräkningsmodell som kan användas för att beräkna olika isoleringstjocklekar för olika typer av fall. Grundprincipen för beräkningsmodellen är att det skall gå att undersöka vilken isoleringstjocklek som behövs då en bestämd energiförlust eller temperatur på isoleringens yta skall uppnås. Isoleringen till varma rör dimensioneras för en reducerad energiförlust medan isolering till kalla rör och ventilationskanaler dimensioneras för en önskad temperatur på isoleringens yta. Livscykelkostnadsanalysen visade att dimensioneringen bör göras för en så liten energiförlust som möjligt.Ett antal olika fall undersöktes med hjälp av beräkningsmodellen. Beräkningarna visade att val av material och ytskikt kan få en betydande inverkan på hur isoleringen måste dimensioneras för att de mål som sätts för den skall uppnås. Att välja en produkt med något lägre värmeledningsförmåga kunde exempelvis minska isoleringsbehovet med nästan 20 % på större rördimensioner. Huruvida isoleringen prioriteras i ett tidigt skede av en projektering eller ej kan också få stora konsekvenser för hur stor ett systems energiförlust blir eftersom en avgörande faktor ofta är om isoleringen får plats i utrymmet. Dimensionering av isolering för kalla system som syftar till att motverka kondensutfällning på isoleringens yta visade sig innebära förhållandevis stora energiförluster. Detta tyder på att isolering av kalla installationer istället borde dimensioneras mot energiförluster.

  • 113.
    Damberg Larsson, Jonas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    GNSS-baserat grävsystem i VA-projekt: En undersökning om GNSS-baserade grävsystem ger ökad produktivitet och säkerhet i medelstora VA-projekt2018Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    The use of machine control has long been common in major road construction and railway construction. However, machine control has become more and more common when digging trenches for pipe laying, but there are not many studies on how the use of machine control affects a work as trench digging for pipe laying.

     

    The report will investigate how a sewer, water and drain pipe project is influenced by using excavators that are equipped with machine control. The investigation will be conducted in two parts and will cover three different themes, economics, work environment and environment.

     

    Different questionnaires were customized for people with different positions. The persons surveyed were workers affected by the use of machine control in projects. These surveys addressed all three of the above topics.

     

    In order to make a deeper study of how the use of machine control affects the economy, figures on costs and progress / productivity were collected from a trench digging and pipe laying project in Toverud, Hammarö. There they used excavators that were equipped with machine control. These figures were compared to a reference project that was also carried out in Hammarö, but in 2009 when machine control was not used.

     

    The result shows that the use of machine control increases productivity while reducing workload and dangers for workers. Because the same type of work is carried out in less time, the total fuel consumption for the project decreases. The calculations showed that a work involving 1100 meters of trench digging and pipe laying. There would be savings up to around 3178 liters of diesel, and that the execution time would be about 15 days faster if the excavators were equipped with machine control.

    A limitation of machine control is that there is a lot of work for the surveyor if many revisions of the drawings are required. It is very important that the surveyor performs well with the line profile, otherwise the positive effects of using machine control at work will disappear. High buildings and forests can be a problem for the reception.

    The conclusion is that productivity increases and quality in the work environment is improved when using machine control.

  • 114. De Magistris, F.
    et al.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Beghello, Luciano
    Järnström, Lars
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Paper Surface Centre.
    Lestelius, Magnus
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences, Paper Surface Centre.
    Influence of paper compressibility on flexographic printing quality2008In: Progress in paper physics seminar 2008, proceedings, Espoo, Finland, 2-5 June 2008 / [ed] Kotomaki K, Koivunen K, Paulapuro H,, 2008, p. 243-245Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    The compression ability of fibres and fibre networks were investigated. The surface and bulk compressions of paper influence calendering, coating, surface sizing ability and the penetration of ink in printing. Two kraft pulps (spruce) were produced in the laboratory to obtain pulps with different levels of xylan. Using those kraft pulps alone or mixed with 50% of a commercial TMP pulp, single-layer sheets were formed in a Formette Dynamique sheet former. The pulps and mixture levels were chosen to obtain papers with systematically altered property variation but with constant grammage. The papers were characterized according to both bulk and surface compressibility. The papers were printed in a flexo IGTF1 laboratory printing press and the transferred amount of ink, dot gain, and mottling were analyzed.

  • 115.
    De Magistris, Federica
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Beghello, Luciano
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Paper Surface Centre.
    Järnström, Lars
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science.
    Lestelius, Magnus
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences, Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science.
    Effect of calendering on the compressibility of papers made with fibre of various properties2010Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    The surface and bulk compressibility of a given paper influence its calendering, coating, surface sizing and printing properties. This study aims at a deeper knowledge of which variable affects the compressibility of paper sheets and how calendering effect different sheet properties. The pulps were characterized by their chemical compositions and physical properties. The bulk compressibility, the surface compressibility and the thickness were evaluated both before and after calendering

  • 116.
    De Magistris, Federica
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Beghello, Luciano
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Järnström, Lars
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Paper Surface Centre.
    Lestelius, Magnus
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences, Paper Surface Centre.
    Influence of Fibre Characteristics of the Surface Roughness of Paper and on Flexographic Print Quality2010Conference paper (Refereed)
  • 117.
    De Vlaemynck, Thijs
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Study of the effect of solvent and molecular weight of TQ1 on the morphology of TQ1:PC60BM and TQ1:PC70BM spin coated systems2018Student paper other, 10 credits / 15 HE creditsStudent thesis
  • 118.
    Deshpande, Raghu
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    The initial phase of sodium sulfite pulping of softwood: A comparison of different pulping options2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Single stage and two-stage sodium sulfite cooking were carried out on either spruce, pine or pure pine heartwood chips to investigate the influence of several process parameters on the initial phase of such a cook down to about 60 % pulp yield. The cooking experiments were carried out in the laboratory with either a lab-prepared or a mill-prepared cooking acid and the temperature and time were varied. The influences of dissolved organic and inorganic components in the cooking liquor on the final pulp composition and on the extent of side reactions were investigated. Kinetic equations were developed and the activation energies for delignification and carbohydrate dissolution were calculated using the Arrhenius equation. A better understanding of the delignification mechanisms during bisulfite and acid sulfite cooking was obtained by analyzing the lignin carbohydrate complexes (LCC) present in the pulp when different cooking conditions were used. It was found that using a mill-prepared cooking acid beneficial effect with respect to side reactions, extractives removal and higher stability in pH during the cook were observed compared to a lab-prepared cooking acid. However, no significant difference in degrees of delignification or carbohydrate degradation was seen.

     The cellulose yield was not affected in the initial phase of the cook however; temperature had an influence on the rates of both delignification and hemicellulose removal. It was also found that the  corresponding activation energies increased in the order:  xylan, glucomannan, lignin and cellulose. The cooking temperature could thus be used to control the cook to a given carbohydrate composition in the final pulp. Lignin condensation reactions were observed during acid sulfite cooking, especially at higher temperatures. The LCC studies indicated the existence of covalent bonds between lignin and hemicellulose components with respect to xylan and glucomannan. LCC in native wood showed the presence of phenyl glycosides, ϒ-esters and α-ethers; whereas the α-ethers  were affected during sulfite pulping. The existence of covalent bonds between lignin and wood polysaccharides might be the rate-limiting factor in sulfite pulping.

  • 119.
    Deshpande, Raghu
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    The initial phase of the sodium bisulfite pulping of softwood dissolving pulp2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The sulfite pulping process is today practised in only a small number of pulp mills around the globe and the number of sulfite mills that use sodium as the base (cation) is less than five. However, due to the increasing interest in the wood based biorefinery concept, the benefits of sulfite pulping and especially the sodium based variety, has recently gained a lot of interest. It was therefore considered to be of high importance to further study the sodium based sulfite process to investigate if its benefits could be better utilized in the future in the production of dissolving pulps. Of specific interest was to investigate how the pulping conditions in the initial part of the cook (≥ 60 % pulp yield) should be performed in the best way.

    Thus, this thesis is focused on the initial phase of single stage sodium bisulfite cooking of either 100 % spruce or 100 % pine wood chips. The cooking experiments were carried out with either a lab prepared or a mill prepared cooking acid and the temperature and cooking time were varied. Activation energies for different wood components were investigated as well as side reactions concerning the formation of thiosulfate and sulfate.

  • 120.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Grundberg, Hans
    Domsjö Fabriker AB, Örnsköldsvik, Sweden.
    Sundvall, Lars
    MoRe Research, Örnsköldsvik, Sweden.
    Giummarella, Nicola
    Wallenberg Wood Science Center, School of Chemical Science and Engeneering, Royal Institute of Technology, KTH, 100 44, Stockholm, Sweden.
    Henriksson, Gunnar
    Wallenberg Wood Science Center, School of Chemical Science and Engeneering, Royal Institute of Technology, KTH, 100 44, Stockholm, Sweden.
    Lawoko, Martin
    Wallenberg Wood Science Center, School of Chemical Science and Engeneering, Royal Institute of Technology, KTH, 100 44, Stockholm, Sweden.
    The Reactivity of Lignin Carbohydrate Complex (LCC) During Manufacture of Dissolving Sulphite Pulp from Softwood2018In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, p. 315-322Article in journal (Refereed)
  • 121.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Sundvall, Lars
    MoRe Research Örnsköldsvik.
    Grundberg, Hans
    Domsjö Fabriker Örnsköldsvik.
    Some process aspects on acid sulphite pulping of softwood2016In: Journal of Science & Technology for Forest Products and Processes, ISSN 1927-6311, E-ISSN 1927-632X, Vol. 6, no 2, p. 48-54Article in journal (Refereed)
  • 122.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sundvall, Lars
    MoRe Research, Örnsköldsvik, Sweden.
    Grundberg, Hans
    Domsjö Fabriker AB, Örnsköldsvik, Sweden.
    The Initial Phase of Sodium Bisulfite Pulping of Pine, Part II2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 3, p. 379-385Article in journal (Refereed)
    Abstract [en]

    Single stage sodium bisulfite cooking of pine was carried out to investigate the influence of time and temperature in the initial phase of the cook. The cooking experiments were carried out using either a lab or a mill prepared cooking acid and the initial stage of the cook was extended up to 5 h cooking time. The impact of temperature on wood components and side reactions was analyzed between 142°C and 165°C. Arrhenius equation was used to determine the influence of temperature on wood components during the initial phase of bisulfite cooking and the activation energy was calculated for delignification rate, cellulose degradation and hemicellulose dissolution with regard to glucomannan and xylan. The extent of extractives removal at different temperature and time was also analyzed.

  • 123.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sundvall, Lars
    MoRe Research.
    Grundberg, Hans
    Domsjö Fabriker.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    New findings in sulfite pulping of softwood dissolving pulps2015In: 5th Avancell Conference Chalmers University of Technology  Gothenburg Sweden, October 6-7 2015, 2015Conference paper (Other academic)
    Abstract [en]

    Karlstads University has for a long time done research on sulfite pulping with the purpose to increase the knowledge on sulfite pulping, to verify old fundamental results an to keep the knowledge on sulfite pulping alive. The basic objective during the last years has been to increase the value of the products produced in such a process and the vision is to make sulfite pulps the preferred pulp grade for dissolving pulps. These studies have so far included spruce and pine. Domsjö Fabriker and MoRe Research in Örnsköldsvik, Sweden have been industry partners in this project.

  • 124.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Sundvall, Lars
    MoRe Research.
    Grundberg, Hans
    Domsjö.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Some process aspects on single-stage bisulfite pulping of pine2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 3, p. 379-385Article in journal (Refereed)
    Abstract [en]

    Sulfite pulping of pine is well-known to be a risky process because problematic lignin conden-sation reactions can occur resulting in poor pulp quality. However, sulfite pulping of pine is interesting of economic reasons as pine wood is cheaper than spruce. Therefore it has become interesting to investigate sulfite pulping again to determine if old data are still valid. Thus sodium bisulfite pulping of pine was carried out to investigate the influence of time, temperature and cooking acid quality. A small comparison of spruce pulping was also included. By using different cooking temperatures the activation energies for delignification and for degradation of cellulose and hemicelluloses could be determined. The results showed no lignin condensation reactions, thus it was not problematic to carry out these pine cooking experiments. It was found that glucomannan had higher activation energy than xylan and the activation energies of these hemicelluloses were lower than the corresponding value for the lignin degradation. It was found that the activation energy for bisulfite pulping of pine was slightly lower than the activation energy for bisulfite pulping of spruce.

  • 125.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sundvall, Lars
    MoRe Research, Örnsköldsvik, Sweden.
    Grundberg, Hans
    Domsjö Fabriker, Örnsköldsvik, Sweden.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    The influence of different types of bisulfite cooking liquors on pine wood components2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 3, p. 5961-5973Article in journal (Refereed)
    Abstract [en]

    Single stage sodium bisulfite cooking of pine was carried out to study the initial phase of the bisulfite cook and the experiments were carried out using either a lab or a mill prepared cooking acid. The chemical consumption, the pH profile and the pulp yield with respect to cellulose, lignin, glucomannan, xylan and extractives were investigated. The pulp composition with respect to carbohydrates and lignin content was summarized in a kinetic model. The initial phase of the bisulfite cook was extended to 5 h cooking time down to a final pulp yield of about 60 %. The side reactions with respect to thiosulfate and sulfate formation were investigated continuously in all experiments. The cooking temperature used in these experiments was 154 °C.

  • 126.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sundvall, Lars
    MoRe research.
    Grundberg, Hans
    Domsjö.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    The influence of the temperature on the initial phase of sodium bisulfite pulping of spruce2015In: O Papel, ISSN 0031-1057, Vol. 76, no 4, p. 56-61Article in journal (Refereed)
  • 127.
    Deshpande, Raghu
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sundvall, Lars
    MoRe Research Örnsköldsvik.
    Grundberg, Hans
    Domsjö Fabriker Örnsköldsvik.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    The Initial Phase of Sodium Bisulfite Pulping of Spruce: Part 12016In: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 50, no 2, p. 293-300Article in journal (Refereed)
  • 128.
    Deshpande, Raghu
    et al.
    MoRe Research, Domsjö Fabriker, Karlstads universitet.
    Sundvall, Lars
    MoRe Research.
    Grundberg, Hans
    Domsjö Fabriker.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    The magic of sulphite pulping: The critical first stage of a dissolving pulp cook2013Conference paper (Other academic)
    Abstract [en]

    A PhD project was started in 2012 with the purpose to in depth examine the first and second part of a sodium sulfite dissolving pulp cook including a following extraction stage. The experimental study started with the first part of the cook when using spruce or pine as the wood raw material and when using lab or mill cooking liquors. A large number of cooking experiments have been performed and a lot of data has been obtained and the risk for obtaining a black cook has been especially observed. In the latter case the thiosulphate content is very critical as it can both lead to a black cook and to decomposition reactions in the cooking liquor. How to avoid problematic cooking conditions will be especially highlighted in the project but ways to produce new pulp grades and new chemicals will be equally important

  • 129.
    Drechsler, Michal
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Modeller i kemi2013In: Modeller, analogier och metaforer i naturvetenskapsundervisning / [ed] Fredrik Jeppsson & Jesper Haglund, Lund: Studentlitteratur AB, 2013, 1, p. 77-90Chapter in book (Other academic)
  • 130.
    Edström, Emelie
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Solvent adsorption in SFC: Adsorption of methanol under supercritical conditions2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Chromatography is a widely used separation technique including many different modes, for example supercritical fluid chromatography (SFC) which uses a supercritical fluid as mobile phase. A supercritical fluid is achieved when a substance is subjected to a temperature and pressure above the critical point and the boundary between the liquid phase and gas phase is erased. The interest for SFC has increased in recent years, mainly for separation of chiral molecules in the pharmaceutical industry. What makes SFC interesting is that it is a quick, cost-efficient and green method. This is in part due to less organic solvent used in the mobile phase in SFC compared with liquid chromatography and that the carbon dioxide that represents the major part of the mobile phase is a by-product from other processes.

    In SFC modifiers, often small alcohols, are added to carbon dioxide based mobile phase in order to increase the solubility of polar compounds. In this study the adsorption of methanol to two different stationary phases; Kromasil-Diol and chiral Lux Cellulose-4 were studied. Adsorption is a phenomenon where surface interactions crate a higher density of molecules at the surface than in the bulk.

    The aim of this work has been to study the adsorption of modifier (methanol) to the stationary phase both to determine the extent of adsorption and the kinetics for system equilibration. These findings were then put into perspective of normal use of SFC for separation of molecules.

    There are a number of techniques for measuring adsorption; in this study the tracer pulse method is used. This is a pulse method where a concentration plateau is created and an isotope labelled molecule is injected. This was performed in the mobile phase composition from pure carbon dioxide to pure methanol. In addition to the tracer pulse experiments the isotope effect, the eluent flow, equilibration times for the column and retention times for a set of analytes were measured. For the Diol column no large isotope effect was observed, the method was also proved to be highly reproducible since several runs gave consistent results. Calculations based on the experimental data showed that a 6.3 Å thick layer was built up at a methanol fraction of 13% (v/v), corresponding to a monolayer. Changes of the methanol fraction below the saturation level has has greater effect on the retention factor for the analytes than at higher methanol fractions, when the monolayer was saturated. The conclusion of this is that SFC is more stable in the area where the layer has been built up.

    A preliminary study has been made for the chiral Lux Cellulose-4 column which was not as conclusive as for the Kromasil-Diol column. This type of column needs further studies to confirm the deviating observations and to investigate the cause for these.

  • 131.
    Ekbåge, Daniel
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Process modelling based on data from an evaporation and a CTMP process: Analysis of energy efficiency and process variability2018Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The manufacture of pulp and paper is an energy intensive process configured of several unit processes that shape a network of flows of wood chips, chemical pulp, mechanical pulp, paperboard, steam and other important components. Improved energy efficiency supports sustainability of the process and the products. With the purpose of monitoring and controlling, information from multiple process and quality variables is continuously collected in the process data system. This data may be of time-varying nature and the variability might potentially span from seasonal to time-wise shorter variations and there are in some cases a need for predicting certain properties.

    By applying models based on process data there is a potential to increase the knowledge of the process characteristics, investigate the applicability of predictive models and identify optimization opportunities. Based on data from an evaporation and a CTMP plant, process models have been developed with the aim of improving the energy efficiency and studying process variability.  

  • 132.
    Ekbåge, Daniel
    et al.
    Store Enso Pulp & Paper Asia AB, Karlstad Res Ctr, POB 9090, SE-65009 Karlstad, Sweden..
    Nilsson, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Potential energy improvements in a multiple-effect evaporation system: Case studies of heat recovery2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 4, p. 583-591Article in journal (Refereed)
    Abstract [en]

    The primary objective of this study was to quantify the amount of excess energy that is present in the evaporation system of an integrated pulp and paper-board mill and to analyze a number of energy recovery cases. These focus on improving the energy efficiency in the evaporation plant and are mainly based on the process data of performance tests from the full-scale production site. A computer script was developed in order to analyze the process streams and can be used to construct the Grand Composite Curve (GCC) of the evaporation system. In addition, the study identified seasonal variations in the potential excess of energy (higher in warmer weather and lower, or even non-existent, in colder) and suggestions are made as to how this energy may be used in a thermodynamically optimal way. In the case studies, the thermodynamically optimal method of recovering heat involved a combination of sensible heat and flash evaporation, indicating the maximum reduction in steam consumption. For the case of only utilizing sensible heat outside the evaporator system to pre-heat one of the liquor flows, the results indicated a lower reduction in steam but also a lower capital cost.

  • 133.
    Ekbåge, Daniel
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Nilsson, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Håkansson, Helena
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Time series analysis of refining conditions and estimated pulp properties in a chemi-thermomechanical pulp process2019In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 14, no 3, p. 5451-5466Article in journal (Refereed)
    Abstract [en]

    Frequently sampled process data from a conical disc refiner and infrequently sampled pulp data from a full scale chemi-thermomechanical pulp (CTMP) mill were evaluated to study autocovariance with aspects of potential dynamic modelling applicability. Two trial measurements with an online pulp analyzer at decreased sampling intervals were performed. For variability analysis, time-series containing up to one day of operational data were used. At the chip refiner, the clearest significant autocovariance was identified for the specific electricity consumption, based on the longer sequences. Most of the estimated pulp properties indicated low or non-significant autocovariance, limiting applicability of a specific dynamic model. A mill trial was conducted to investigate the impact from an increase in the conical disc gap on the specific electricity consumption and the resulting freeness. The response time from the gap change in the refiner to measured change in freeness was estimated at 19 min, which was approximately the hydraulic residence time in the latency chest. The relevance of this study lies in applicability of mill-data-driven modelling to capture the dynamics of a specific refining process. Through mill trials the sampling speed of pulp properties was more than doubled to gain insights into short term systematic variations by applying time-series-analysis.

  • 134.
    Ekbåge, Daniel
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Nilsson, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Håkansson, Helena
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Trial measurements in a CTMP-process to perform time-series analysis of refining conditions and estimated pulp properties2017Conference paper (Other academic)
  • 135.
    Ekeroth, Jesper
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Effektivisering genom rengöring av kylbatterier och avgasning av köldbäraren2016Independent thesis Basic level (professional degree), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Energy issues are a priority in today's society and will probably be for many years to come. In order to achieve progress in this struggle towards a more energy efficient world, global optimizations will be needed and new ways of thinking need to be realized.

    In the food industry, there is great potential for optimizations and new ways of thinking. One problem area is that many grocery stores do not open their refrigerators and freezers and clean them internally, they only clean the visible surfaces. Failure to clean inside refrigerated display may cause the burdening and dirt into the system that is adversely affected. These may include impacts on the cooling coil, reducing air flow and clog the drains. Impacts on the cooling coil and the air flow in turn could lead to the destruction of food due to high temperatures in refrigerators and freezers. Clogged drains can lead to water leakage, which then can run out on the shop floor.

    During this project, optimization efforts have been made and these include cleaning the cooling coils inside the refrigerator and freezer cabinets and degassing of the brine. The cleaning has been done with overheated steam to remove any burdening to the cooling coils and fans, and all surfaces in refrigerators and freezers. This has been done to see if energy can be saved by increasing the thermal conductivity of the cooling coil.

    The tests that have been done to see if it is possible to save energy by cleaning are ampere- , flow- and temperature measurement.

    Degassing of the coolant has been made on the basis of the same theory as cleaning. By degassing where the ambition that the brine could pick up more veil and thus increase the efficiency of the cooling system.

    Degassing the coolant provides improvements in the sustainability of the system with a reduced risk of corrosion, but what happens to the heat transfer capability is relatively unknown, it has been studied through power measurements on chiller compressor.

    After the test period the results of cleaning tests show that the power demand goes down, while degassing not had any impact. Degassing showed no efficiency of the system because the oxygen levels remained high.

  • 136.
    Encarnacao, Joao Crispim
    et al.
    Ridgeview Instruments AB Uppsala.
    Barta, Pavel
    Charles Univ. Prague Czech Republic.
    Fornstedt, Torgny
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Andersson, Karl
    Ridgeview Instruments AB Uppsala; Uppsala universitet.
    Impact of assay temperature on antibody binding characteristics in living cells: A case study2017In: BIiomedical reports, ISSN 2049-9434, Vol. 7, no 5, p. 400-406Article in journal (Refereed)
    Abstract [en]

    Kinetic and thermodynamic studies of ligand-receptor interactions are essential for increasing the understanding of receptor activation mechanisms and drug behavior. The characterization of molecular interactions on living cells in real-time goes beyond most current binding assays, and provides valuable information about the dynamics and underlying mechanism of the molecules in a living system. The effect of temperature on interactions in cell-based assays is, however, rarely discussed. In the present study, the effect of temperature on binding of monoclonal antibodies, cetuximab and pertuzumab to specific receptors on living cancer cells was evaluated, and the affinity and kinetics of the interactions were estimated at selected key temperatures. Changes in the behavior of the interactions, particularly in the on- and off-rates were observed, leading to greatly extended time to reach the equilibrium at 21 degrees C compared with at 37 degrees C. However, the observed changes in kinetic characteristics were less than a factor of 10. It was concluded that it is possible to conduct real-time measurements with living cells at different temperatures, and demonstrated that influences of the ambient temperature on the interaction behavior are likely to be less than one order of magnitude.

  • 137. Endres, Isabel
    et al.
    Engström, Gunnar
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre.
    Influence of Calendaring Condition on Paper Surface Characteristics: A Comparison between Hard-Nip, Soft-Nip and Extended Soft-Nip2005In: Tappi Journal, Vol. 4 no 9, 9-14,(2005)Article in journal (Refereed)
  • 138. Endres, Isabel
    et al.
    Engström, Gunnar
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre.
    Local Characterisation of Coated Paper Surface Using a Novel Technique2005Conference paper (Other (popular science, discussion, etc.))
  • 139. Engquist, I.
    et al.
    Lestelius, Magnus
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science.
    Liedberg, B.
    Microscopic Wettability of Ester and Acetate Terminated Self-Assembled Monolayers1997In: Langmuir, Vol. vol 13, p. 4003-4012Article in journal (Refereed)
  • 140. Engquist, I.
    et al.
    Liedberg, B.
    Lestelius, Magnus
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science.
    Hydrogen Bond Interaction between Ester Terminated Self-Assembled Monolayers and Adsorbed Water Molecules and Its Implications for Cluster Formation1995In: Journal of Physical Chemistry, Vol. vol 99, p. 14198-14200Article in journal (Refereed)
  • 141.
    Engström, Gunnar
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Causes of back-trap mottle in lithographic offset prints on coated papers2016In: TAPPI Journal, ISSN 0734-1415, Vol. 15, no 2, p. 91-101Article in journal (Refereed)
    Abstract [en]

    Back-trap mottle is a common and serious print quality problem in lithographic offset printing of coated papers. It is caused by nonuniform ink retransfer from an already printed surface when it passes through a subsequent printing nip with the print in contact with the rubber blanket in that nip. A nonuniform surface porosity gives rise to mottle. A key parameter in mottling contexts is the coating mass distribution, which must be uniform. Good relationships between mottle and mass distribution have also been reported; the mottle pattern coincides with that of the coating mass distribution. High blade pressures, compressible base papers, and high water pick-up between application and metering, which plasticizes the paper, yield uniform mass distributions, but these parameters might have a detrimental effect on the runnability in blade coating in terms of web breaks. The general opinion has been that nonuniform surface porosity is caused by binder migration and enrichment of binder in the coating surface, more in the high coat weight areas and less in the low coat weight areas. Recent research has suggested that a more probable mechanism is depletion of binder in the coating surface. Nonuniform shrinkage of the pigment matrix (filter cake) formed during the consolidation between the first critical concentration (FCC) and the second critical concentration (SCC) is another possible mechanism. Relevant relaxation times for latex and the time scales for consolidation show that the high coat weight areas shrink more than the low coat weight areas in the coating layer. A recent pilot-scale experiment has shown that the drying strategy did not affect the differences in shrinkage between high and low coat weight areas. The drying strategy has a pronounced impact on mottle. A high evaporation rate at the beginning of the evaporation results in less mottle than a low evaporation rate. The least mottle is obtained if the drying is performed with a gap in the course of evaporation between the FCC and the SCC.

  • 142.
    Enmark, Martin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Fundamental Investigations of Supercritical Fluid Chromatography2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis aims at a deeper understanding of Supercritical Fluid

    Chromatography (SFC). Although preparative SFC has started to replace Liquid Chromatography (LC) in the pharmaceutical industry - because of its advantages in speed and its less environmental impact - fundamental understanding is still lacking. Therefore there is no rigid framework to characterize adsorption or to understand the impact of changes in operational conditions.

     

    In Paper I we demonstrated, after careful system verification, that most methods applied to determine adsorption isotherms in LC could not be applied directly in SFC. This was mainly due to operational differences and to the fact that the fluid is compressible which means that everything considered constant in LC varies in SFC.

     

    In Paper II we showed that the most accurate methods for adsorption isotherm determination in LC, the so called plateau methods, do not work properly for SFC. Instead, methods based on overloaded profiles should be preferred.

     

    In Paper III a Design of Experiments approach was successfully used to quantitatively describe the retention behavior of several solutes and the productivity of a two component separation system. This approach can be used to optimize SFC separations or to provide information about the separation system.

     

    In Paper IV severe peak distortion effects, suspected to arise from injection solvent and mobile phase fluid mismatches, were carefully investigated using experiments and simulations. By this approach it was possible to examine the underlying reasons for the distortions, which is vital for method development.

     

    Finally, in Paper V, the acquired knowledge from Paper I-IV was used to perform reliable scale-up in an industrial setting for the first time. This was done by carefully matching the conditions inside the analytical and preparative column with each other. The results could therefore provide the industry with key knowledge for further implementation of SFC.

  • 143.
    Enmark, Martin
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Asberg, Dennis
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Leek, Hanna
    AstraZeneca R&D, Resp Inflammat & Autoimmun, Innovat Med, S-43183 Molndal, Sweden..
    Ohlen, Kristina
    AstraZeneca R&D, Resp Inflammat & Autoimmun, Innovat Med, S-43183 Molndal, Sweden..
    Klarqvist, Magnus
    AstraZeneca R&D, Resp Inflammat & Autoimmun, Innovat Med, S-43183 Molndal, Sweden..
    Samuelsson, Jorgen
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Fornstedt, Torgny
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Evaluation of scale-up from analytical to preparative supercritical fluid chromatography2015In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1425, p. 280-286Article in journal (Refereed)
    Abstract [en]

    An approach for reliable transfer from analytical to preparative scale supercritical fluid chromatography was evaluated. Here, we accounted for the conditions inside the columns as well as to the fact that most analytical instruments are volume-controlled while most preparative scale units are mass-controlled. The latter is a particular problem when performing pilot scale experiments and optimizations prior to scaling up to production scale. This was solved by measuring the mass flow, the pressure and the temperature on the analytical unit using external sensors. Thereafter, it was revealed with a design of experiments approach that the methanol fraction and the pressure are the two most important parameters to control for preserved retention throughout the scale-up; for preserved selectivity the temperature was most important in this particular system. Using this approach, the resulting chromatograms from the preparative unit agreed well with those from the analytical unit while keeping the same column length and particles size. A brief investigation on how the solute elution volume varies with the volumetric flow rate revealed a complex dependency on pressure, density and apparent methanol content. Since the methanol content is a parameter of great importance to control during the scale up, we must be careful when changing operational and column design conditions which generates deviations in pressure, density and methanol content between different columns. (C) 2015 Elsevier B.V. All rights reserved.

  • 144.
    Enmark, Martin
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Forssén, Patrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Samuelsson, Jörgen
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Fornstedt, Torgny
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Determination of adsorption isotherms in supercritical fluid chromatography2013In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1312, p. 124-133Article in journal (Refereed)
    Abstract [en]

    Abstract In this study we will demonstrate the potential of modern integrated commercial analytical SFC-systems for rapid and reliable acquisition of thermodynamic data. This will be done by transferring the following adsorption isotherm determination methods from liquid chromatography (LC) to supercritical fluid chromatography (SFC): Elution by Characteristic Points (ECP), the Retention Time Method (RTM), the Inverse Method (IM) and the Perturbation Peak (PP) method. In order to transfer these methods to SFC in a reliable, reproducible way we will demonstrate that careful system verification using external sensors of mass flow, temperature and pressure are needed first. The adsorption isotherm data generated by the different methods were analyzed and compared and the adsorption isotherms ability to predict new experimental elution profiles was verified by comparing experiments with simulations. It was found that adsorption isotherm data determined based on elution profiles, i.e., ECP, IM and RTM, were able to accurately predict overloaded experimental elution profiles while the more tedious and time-consuming PP method, based on small injections on concentration plateaus, failed in doing so.

  • 145.
    Enmark, Martin
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Physics (from 2013).
    Glenne, Emelie
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Leśko, Marek
    Rzeszów University of Technology, Poland.
    Langborg Weinmann, Annika
    AstraZeneca.
    Leek, Tomas
    AstraZeneca.
    Kaczmarski, Krzysztof
    AstraZeneca.
    Klarqvist, Magnus
    AstraZeneca.
    Samuelsson, Jörgen
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Fornstedt, Torgny
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Investigation of robustness for supercritical fluid chromatography separation of peptides: Isocratic vs gradient mode2018In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1568, p. 177-187Article in journal (Refereed)
    Abstract [en]

    We investigated and compared the robustness of supercritical fluid chromatography (SFC) separations of the peptide gramicidin, using either isocratic or gradient elution. This was done using design of experiments in a design space of co-solvent fraction, water mass fraction in co-solvent, pressure, and temperature. The density of the eluent (CO2-MeOH-H2O) was experimentally determined using a Coriolis mass flow meter to calculate the volumetric flow rate required by the design. For both retention models, the most important factor was the total co-solvent fraction and water mass fraction in co-solvent. Comparing the elution modes, we found that gradient elution was more than three times more robust than isocratic elution. We also observed a relationship between the sensitivity to changes and the gradient steepness and used this to draw general conclusions beyond the studied experimental system. To test the robustness in a practical context, both the isocratic and gradient separations were transferred to another laboratory. The gradient elution was highly reproducible between laboratories, whereas the isocratic system was not. Using measurements of the actual operational conditions (not the set system conditions), the isocratic deviation was quantitatively explained using the retention model. The findings indicate the benefits of using gradient elution in SFC as well as the importance of measuring the actual operational conditions to be able to explain observed differences between laboratories when conducting method transfer.

  • 146.
    Enmark, Martin
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013). Uppsala University.
    Rova, Maria
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Samuelsson, Jörgen
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Örnskov, Eivor
    IMED Biotech Unit, Sweden.
    Schweikart, Fritz
    IMED Biotech Unit, Sweden.
    Fornstedt, Torgny
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Investigation of factors influencing the separation of diastereomers of phosphorothioated oligonucleotides2019In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 411, no 15, p. 3383-3394Article in journal (Refereed)
    Abstract [en]

    This study presents a systematic investigation of factors influencing the chromatographic separation of diastereomers of phosphorothioated pentameric oligonucleotides as model solutes. Separation was carried out under ion-pairing conditions using an XBridge C18 column. For oligonucleotides with a single sulfur substitution, the diastereomer selectivity was found to increase with decreasing carbon chain length of the tertiary alkylamine used as an ion-pair reagent. Using an ion-pair reagent with high selectivity for diastereomers, triethylammonium, it was found the selectivity increased with decreased ion-pair concentration and shallower gradient slope. Selectivity was also demonstrated to be dependent on the position of the modified linkage. Substitutions at the center of the pentamer resulted in higher diastereomer selectivity compared to substitutions at either end. For mono-substituted oligonucleotides, the retention order and stereo configuration were consistently found to be correlated, with Rp followed by Sp, regardless of which linkage was modified. The type of nucleobase greatly affects the observed selectivity. A pentamer of cytosine has about twice the diastereomer selectivity of that of thymine. When investigating the retention of various oligonucleotides eluted using tributylammonium as the ion-pairing reagent, no diastereomer selectivity could be observed. However, retention was found to be dependent on both the degree and position of sulfur substitution as well as on the nucleobase. When analyzing fractions collected in the front and tail of overloaded injections, a significant difference was found in the ratio between Rp and Sp diastereomers, indicating that the peak broadening observed when using tributylammonium could be explained by partial diastereomer separation.

  • 147.
    Enmark, Martin
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Samuelsson, Jörgen
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Fornstedt, Torgny
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    On the Reproducibility between Different Modern Supercritcal Fluid Chromatographic Systems2013Conference paper (Other academic)
    Abstract [en]

    Three different, commercially available, Supercritical Fluid Chromatography (SFC) systems were investigated: Thar Super Pure Discovery Series SFC, Waters UPC2 and Agilent 1260 Infinity SFC. The reason for choosing the two analytical systems from Agilent and Waters is that they represent two of the latest commercial systems available while the semi-preparative instrument was added to widen the study to include instruments also used for preparative purposes. With identical operational conditions set these systems were used to acquire analytical retention data and adsorption isotherms from overloaded injections. The investigation was limited to the use of methanol as modifier and operational conditions, temperature and back pressure most typically observed when utilizing SFC to separate polar compounds. The results clearly show that both analytical retention times and elution profiles are system dependent. Since the overloaded elution profiles are system dependent the adsorption isotherm will also be different. However, this do not mean that the adsorption is different, instead this it is due to the fact that identical instrumental settings, especially pressure and modifier composition settings, does not necessarily mean that the conditions inside the column are identical. This means that it is not possible to transfer an established separation method from one system to another, even if one is using the same column and identical instrument settings. Understanding of SFC-systems will be of fundamental importance for successful transfer of methods between systems, reliable adsorption isotherm determination, and analytical quality work and scaling up from analytical to preparative mode. These issues can probably be solved by measuring mass flow, pressure and temperature along the column, together with a sound understanding of the density variations of the mobile phase. However, the work of finding acceptable applications or guidelines to remove the tedious need for these measurements is currently investigated in our lab. This is a contribution from the Fundamental Separation Science Group www.FSSG.se

  • 148.
    Enmark, Martin
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Samuelsson, Jörgen
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Fornstedt, Torgny
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Using Modern SFC Systems for Adsorption Characterization2013Conference paper (Other academic)
    Abstract [en]

    Recently the pharmaceutical industry has started to replace preparative HPLC with preparative SFC to lower the environmental impact and to increase performance. Reliable characterization of the adsorption processes in SFC is therefore of utmost importance. The key thermodynamic phase system information is obtained by rigorous determination of adsorption isotherm data over a broad concentration range. If properly processed, this data gives not only correct information about the degree of heterogeneity but also the energy of interactions and mono layer capacities of each individual type of adsorption site in the phase system. Ultimately, this can result in identification of the types of interactions, i.e., dipole-dipole, van der Waals interactions etc. In this study we will present transfer of selected adsorption characterization methods, traditionally applied with success in LC, to SFC. We have here transferred all available knowledge from LC – from model selection to validation. We will also, using recent findings, explain the effects of pressure and temperature variations as well as how to accurately measure the volumetric flow rate on a modern analytical SFC system. We will demonstrate how the latest SFC instruments, with some critical modifications; have the potential for rapid and reliable acquisition of thermodynamic data using the ECP method. Finally we will elaborate on how the adsorption depends on density, temperature and modifier content in the mobile phase. This is a contribution from the Fundamental Separation Science Group www.FSSG.se

  • 149.
    Enmark, Martin
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Samuelsson, Jörgen
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Forss, Erik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Forssén, Patrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Fornstedt, Torgny
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Investigation of plateau methods for adsorption isotherm determination in supercritical fluid chromatography2014In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1354, p. 129-138Article in journal (Refereed)
    Abstract [en]

    The Perturbation Peak (PP) method and Frontal analysis (FA) are considered as the most accurate methods for adsorption isotherms determination in liquid chromatography. In this study we investigate and explain why this is not the case in Supercritical Fluid Chromatography (SFC), where the PP method does not work at all, using a modern analytical system. The main reason was found to be that the solute to be studied must be dissolved in the MeOH reservoir before it is mixed with CO2. Since the solute occupies a certain partial volume in the reservoir, the larger the solute content the larger this fractional volume will be, and the final MeOH fraction in the mobile phase will then be smaller compared to the bulk mobile phase without solute in the modifier. If the retention of small injections on the concentration plateaus, i.e., “analytical-size” perturbation peaks, is sensitive to small variations of MeOH in the eluent, this will seriously decrease the accuracy of the PP method. This effect was verified and compensated for and we also demonstrated that the same problem will occur in frontal analysis, another concentration plateau method.

  • 150.
    Enmark, Martin
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Samuelsson, Jörgen
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Undin, Torgny
    Uppsala University Analytisk Kemi.
    Fornstedt, Torgny
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Characterization of an unusual adsorption behavior of racemic methyl-mandelate on a tris-(3,5-dimethylphenyl) carbamoyl cellulose chiral stationary phase2011In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1218, no 38, p. 6688-6696Article in journal (Refereed)
    Abstract [en]

    An interesting adsorption behavior of racemic methyl mandelate on a tris-(3,5-dimethylphenyl)carbamoyl cellulose chiral stationary phase was theoretically and experimentally investigated. The overloaded band of the more retained enantiomer had a peculiar shape indicating a type V adsorption isotherm whereas the overloaded band of the less retained enantiomer had a normal shape indicating a type I adsorption behavior. For a closer characterization of this separation, adsorption isotherms were determined and analyzed using an approach were Scatchard plots and adsorption energy distribution (AED) calculations are combined for a deeper analysis. It was found that the less retained enantiomer was best described by a Tóth adsorption isotherm while the second one was best described with a bi-Moreau adsorption isotherm. The latter model comprises non-ideal adsorbate–adsorbate interactions, providing an explanation to the non-ideal adsorption of the more retained enantiomer. Furthermore, the possibility of using the Moreau model as a local model for adsorption in AED calculations was evaluated using synthetically generated raw adsorption slope data. It was found that the AED accurately could predict the number of adsorption sites for the generated data. The adsorption behavior of both enantiomers was also studied at several different temperatures and found to be exothermic; i.e. the adsorbate–adsorbate interaction strength decreases with increasing temperature. Stochastic analysis of the adsorption process revealed that the average amount of adsorption/desorption events increases and the sojourn time decreases with increasing temperature.

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