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  • 101.
    Danish, Muhammad
    et al.
    East China Univ Sci & Technol, State Environm Protect Key Lab Environm Risk Asse, Shanghai 200237, Peoples R China..
    Gu, Xiaogang
    East China Univ Sci & Technol, State Environm Protect Key Lab Environm Risk Asse, Shanghai 200237, Peoples R China..
    Lu, Shuguang
    East China Univ Sci & Technol, State Environm Protect Key Lab Environm Risk Asse, Shanghai 200237, Peoples R China..
    Zhang, Xiang
    East China Univ Sci & Technol, State Environm Protect Key Lab Environm Risk Asse, Shanghai 200237, Peoples R China..
    Fu, Xiaori
    East China Univ Sci & Technol, State Environm Protect Key Lab Environm Risk Asse, Shanghai 200237, Peoples R China..
    Xue, Yunfei
    East China Univ Sci & Technol, State Environm Protect Key Lab Environm Risk Asse, Shanghai 200237, Peoples R China..
    Miao, Zhouwei
    East China Univ Sci & Technol, State Environm Protect Key Lab Environm Risk Asse, Shanghai 200237, Peoples R China..
    Ahmad, Ayyaz
    Muhammad Nawaz Sharif Univ Engn & Technol, Dept Chem Engn, Multan, Pakistan..
    Naqvi, Muhammad
    Mälardalens högskola.
    Qureshi, Abdul Sattar
    Univ Sindh, Inst Biotechnol & Genet Engn, Jamshoro 76080, Pakistan..
    The Effect of Chelating Agents on Enhancement of 1,1,1-Trichloroethane and Trichloroethylene Degradation by Z-nZVI-Catalyzed Percarbonate ProcessL2016Ingår i: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 227, nr 9, s. 1-14, artikel-id 301Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study primarily focused on the performance of 1,1,1-trichloroethane (1,1,1-TCA) and trichloroethylene (TCE) degradation involving redox reactions in zeolite-supported nanozerovalent iron composite (Z-nZVI)-catalyzed sodium percarbonate (SPC) system in aqueous solution with five different chelating agents (CAs) including oxalic acid (OA), citric acid monohydrate (CAM), glutamic acid (GA), ethylenediaminetetraacetic acid (EDTA), and L-ascorbic acid (ASC). The experimental results showed that the addition of OA achieved almost 100 % degradation of 1,1,1-TCA and TCE. The addition of CAM and GA also significantly increased the contaminant degradation, while excessive addition of them inhibited the degradation. In contrast, EDTA and ASC showed negative impacts on 1,1,1-TCA and TCE degradation, which might be due to the strong reactivity with iron and OH center dot scavenging characteristics. The efficiency with CA addition on 1,1,1-TCA and TCE degradation decreased in the order of OA > CAM > GA > no CAs > EDTA> ASC. The extensive investigations using probe compound tests and scavenger tests revealed that both contaminants degraded primarily by OH center dot and O-2(-center dot) in chelated Z-nZVI-catalyzed SPC system. The significant improvement in 1,1,1-TCA and TCE degradation efficiency was accredited due to the (i) increase in concentration of Fe2+ and (ii) continuous generation of OH center dot radicals and maintenance of its quantity, ensuring more stability in the aqueous solution. Finally, the complete mineralization of 1,1,1-TCA and TCE in the OA-chelated, Z-nZVI-catalyzed SPC system was confirmed without any chlorinated intermediate by-products detected, demonstrating a great potential of this technique in the application of groundwater remediation.

  • 102.
    Danish, Muhammad
    et al.
    E China Univ Sci & Technol, Peoples R China; Gujarat Univ, Pakistan.
    Naqvi, Muhammad
    Malardalen Univ.
    Farooq, Usman
    Gujarat Univ, Pakistan.
    Naqvi, Salman
    Univ Teknol PETRONAS, Malaysia..
    Characterization of South Asian agricultural residues for potential utilization in future 'energy mix'2015Ingår i: Energy Procedia / [ed] J. Yan, T. Shamim, H Li SK Chou, Elsevier, 2015, Vol. 75, s. 2974-2980Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper characterizes various locally available agricultural residues in South Asian region to evaluate their potential as feedstock for renewable energy production and contributing toward solving energy crisis and environmental issues. The thermo-chemical characterization has been performed in order to determine if the residues have potential to be used in biomass conversion technologies producing combined heat and power. The characterization methods for comparing different agricultural residues include proximate and ultimate analysis, heating value, ash content, thermo gravimetric analysis (TGA) and structural composition analysis (SCA). Widely available agricultural wastes in South Asian region were selected for the characterization i.e. bagasse, almond shell, corn cob, cotton stalks, wheat straw, sawdust, corn leaf, rice husk, rice straw, and corn straw. The analysis showed that the corn cob had the highest moisture content that will result in low energy efficiency of the thermal conversion technology due to energy requirement for drying. Whereas almond shell had the lowest moisture content. Ash and volatile contents were found to be highest in rice straw and almond shell respectively. The thermo gravimetric analysis showed that most of the agricultural residues can be easily decomposed and represent potential feedstock for biomass flexible combined heat and power systems through pyrolysis or gasification.

  • 103. De Magistris, F.
    et al.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Beghello, Luciano
    Järnström, Lars
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Paper Surface Centre.
    Lestelius, Magnus
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper, Paper Surface Centre.
    Influence of paper compressibility on flexographic printing quality2008Ingår i: Progress in paper physics seminar 2008, proceedings, Espoo, Finland, 2-5 June 2008 / [ed] Kotomaki K, Koivunen K, Paulapuro H,, 2008, s. 243-245Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
    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.

  • 104.
    De Magistris, Federica
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för energi-, miljö- och byggteknik.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Beghello, Luciano
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Paper Surface Centre.
    Järnström, Lars
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Paper Surface Centre. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Materialvetenskap.
    Lestelius, Magnus
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper, Paper Surface Centre. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Materialvetenskap.
    Effect of calendering on the compressibility of papers made with fibre of various properties2010Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
    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

  • 105.
    De Magistris, Federica
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Beghello, Luciano
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Järnström, Lars
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Paper Surface Centre.
    Lestelius, Magnus
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper, Paper Surface Centre.
    Influence of Fibre Characteristics of the Surface Roughness of Paper and on Flexographic Print Quality2010Konferensbidrag (Refereegranskat)
  • 106. De Magistris, Federica
    et al.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Svedinger-Andersson, Maria
    Pulping to different xylan contents and its impact on the pulp quality2008Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
  • 107.
    Deshpande, Raghu
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    The initial phase of sodium sulfite pulping of softwood: A comparison of different pulping options2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    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.

  • 108.
    Deshpande, Raghu
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    The initial phase of the sodium bisulfite pulping of softwood dissolving pulp2015Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    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.

  • 109.
    Deshpande, Raghu
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Germgård, Ulf
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (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 Softwood2018Ingår i: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, s. 315-322Artikel i tidskrift (Refereegranskat)
  • 110.
    Deshpande, Raghu
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Germgård, Ulf
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Sundvall, Lars
    MoRe Research Örnsköldsvik.
    Grundberg, Hans
    Domsjö Fabriker Örnsköldsvik.
    Some process aspects on acid sulphite pulping of softwood2016Ingår i: Journal of Science & Technology for Forest Products and Processes, ISSN 1927-6311, E-ISSN 1927-632X, Vol. 6, nr 2, s. 48-54Artikel i tidskrift (Refereegranskat)
  • 111.
    Deshpande, Raghu
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Sundvall, Lars
    MoRe Research, Örnsköldsvik, Sweden.
    Grundberg, Hans
    Domsjö Fabriker AB, Örnsköldsvik, Sweden.
    The Initial Phase of Sodium Bisulfite Pulping of Pine, Part II2016Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, nr 3, s. 379-385Artikel i tidskrift (Refereegranskat)
    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.

  • 112.
    Deshpande, Raghu
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Sundvall, Lars
    MoRe Research.
    Grundberg, Hans
    Domsjö Fabriker.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    New findings in sulfite pulping of softwood dissolving pulps2015Ingår i: 5th Avancell Conference Chalmers University of Technology  Gothenburg Sweden, October 6-7 2015, 2015Konferensbidrag (Övrigt vetenskapligt)
    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.

  • 113.
    Deshpande, Raghu
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Sundvall, Lars
    MoRe Research.
    Grundberg, Hans
    Domsjö.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Some process aspects on single-stage bisulfite pulping of pine2016Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, nr 3, s. 379-385Artikel i tidskrift (Refereegranskat)
    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.

  • 114.
    Deshpande, Raghu
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Sundvall, Lars
    MoRe Research, Örnsköldsvik, Sweden.
    Grundberg, Hans
    Domsjö Fabriker, Örnsköldsvik, Sweden.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    The influence of different types of bisulfite cooking liquors on pine wood components2016Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, nr 3, s. 5961-5973Artikel i tidskrift (Refereegranskat)
    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.

  • 115.
    Deshpande, Raghu
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Sundvall, Lars
    MoRe research.
    Grundberg, Hans
    Domsjö.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    The influence of the temperature on the initial phase of sodium bisulfite pulping of spruce2015Ingår i: O Papel, ISSN 0031-1057, Vol. 76, nr 4, s. 56-61Artikel i tidskrift (Refereegranskat)
  • 116.
    Deshpande, Raghu
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Sundvall, Lars
    MoRe Research Örnsköldsvik.
    Grundberg, Hans
    Domsjö Fabriker Örnsköldsvik.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    The Initial Phase of Sodium Bisulfite Pulping of Spruce: Part 12016Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 50, nr 2, s. 293-300Artikel i tidskrift (Refereegranskat)
  • 117.
    Deshpande, Raghu
    et al.
    MoRe Research, Domsjö Fabriker, Karlstads universitet.
    Sundvall, Lars
    MoRe Research.
    Grundberg, Hans
    Domsjö Fabriker.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    The magic of sulphite pulping: The critical first stage of a dissolving pulp cook2013Konferensbidrag (Övrigt vetenskapligt)
    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

  • 118.
    Ekbåge, Daniel
    Karlstads universitet.
    Performance of neural networks and feature selection algorithms on board strength predictionsManuskript (preprint) (Övrigt vetenskapligt)
  • 119.
    Ekbåge, Daniel
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Process modelling based on data from an evaporation and a CTMP process: Analysis of energy efficiency and process variability2018Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    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.  

  • 120.
    Ekbåge, Daniel
    et al.
    Store Enso Pulp & Paper Asia AB, Karlstad Res Ctr, POB 9090, SE-65009 Karlstad, Sweden..
    Nilsson, Lars
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Potential energy improvements in a multiple-effect evaporation system: Case studies of heat recovery2016Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, nr 4, s. 583-591Artikel i tidskrift (Refereegranskat)
    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.

  • 121.
    Ekbåge, Daniel
    et al.
    Karlstads universitet.
    Nilsson, Lars
    Karlstads universitet.
    Håkansson, Helena
    Karlstads universitet.
    Characterization of process and material properties to reduce grade change loss in board productionManuskript (preprint) (Övrigt vetenskapligt)
  • 122.
    Ekbåge, Daniel
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Nilsson, Lars
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Håkansson, Helena
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Lin, Ping-I
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för hälsovetenskaper (from 2013).
    Multiple linear regression modelling of pulp and handsheet properties based on fiber morphology measurements and process data2020Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 15, nr 1, s. 654-676Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A multiple regression model was evaluated to predict pulp and handsheet properties including z-directional tensile strength (z-strength) and Scott bond values. One hypothesis that was central for the model evaluation was that the crill content, as measured with ultraviolet and infrared lights, would improve the statistical models. A chemi-thermomechanical pulp (CTMP) mill designed with two parallel primary refining lines and a reject refiner was the basis for this study, and all process data and pulp samples were gathered from the specific process. Pulp was extracted from the process for an extended period from a position after the latency chest (primary refined pulp) and from the pulp-stream exiting the mill to the board machine (accept pulp). The crill content was positively correlated to the z-strength of the accept pulp, explaining 55% of the variance with a linear regression model with the drill content as the sole predictor. The estimation model of the z-strength of accept pulp was based on a combination of the crill content, freeness, fibril perimeter for longer fibers, and mean kink angle, and resulted in an R-2 of 0.79. When applying cross-validation to determine the predictive model performance, the highest R-2 obtained was 0.67. This latter model included the crill content, fibril perimeter, and mean kink angle as predictors.

  • 123. Endres, Isabel
    Compression uniformity measurements on coated and uncoated paper surfaces2006Doktorsavhandling, monografi (Övrigt vetenskapligt)
  • 124. Endres, Isabel
    Compression uniformity measurements on coated anduncoated paper surfaces2004Licentiatavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    Paper is exposed to compressive stresses at several occasions in its production process and in subsequent printing operations. In the press section of a paper machine, the fibre web is mechanically dewatered by compression. In calendering its surface properties, such as gloss and smoothness, are enhanced by compressing the paper between rollers or plates. Also in rotogravure printing, paper is pressed against the printing cylinder in order to create good contact and thus good ink transfer. In all situations where paper is compressed, its local structural properties control the compression uniformity and consequently the end-product quality, e.g. in the form of gloss variation, calender blackening, ink absorption variations, printing failure such as missing dots in rotogravure.



    This work describes the development and application of a technique to measure local compression uniformity. Local pressure distributions on a paper surface under compression are quantitatively characterized using a custom-made pressure-sensitive film in a hydraulic press, a CCD-camera and image analysis. The technique was tested in the fields of coating, calendering and printing. A measure for the load coverage ability of coating was obtained. It gives insight into how well a coating covers the base paperÕs non-uniformity under compression. In a second study, different calendering techniques were analysed and it was found that the local structure of the load-bearing flocs was changed significantly depending on the calendering conditions. In a third study, the relation between missing dots in rotogravure and the underlying paper structure was outlined. Missing dots predominantly occurred in valleys of a certain critical size, situated in direct proximity to load-bearing structure elements in the paper

  • 125. Endres, Isabel
    et al.
    Engström, Gunnar
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Paper Surface Centre.
    Influence of Calendaring Condition on Paper Surface Characteristics: A Comparison between Hard-Nip, Soft-Nip and Extended Soft-Nip2005Ingår i: Tappi Journal, Vol. 4 no 9, 9-14,(2005)Artikel i tidskrift (Refereegranskat)
  • 126. Endres, Isabel
    et al.
    Engström, Gunnar
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Paper Surface Centre.
    Local Characterisation of Coated Paper Surface Using a Novel Technique2005Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
  • 127. Endres, Isabel
    et al.
    Tietz, M
    Blade, Film and Curtain Coating Techniques and Their Influence on Paper Surface Characteristics2005Konferensbidrag (Refereegranskat)
  • 128. Endres, Isabel
    et al.
    Tietz, M
    Blade, film and curtain coating techniques and their influence on paper surface characteristics2007Ingår i: TAPPI JOURNAL 6(11): 24-32Artikel i tidskrift (Refereegranskat)
  • 129. Endres, Isabel
    et al.
    Vomhoff, H.
    Ström, G.
    Microscale compression uniformity measurements on coated paper surfaces2005Ingår i: Tappi J., 4(9), 9-14, (2005)Artikel i tidskrift (Refereegranskat)
  • 130. Engquist, I.
    et al.
    Lestelius, Magnus
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Paper Surface Centre. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Materialvetenskap.
    Liedberg, B.
    Microscopic Wettability of Ester and Acetate Terminated Self-Assembled Monolayers1997Ingår i: Langmuir, Vol. vol 13, s. 4003-4012Artikel i tidskrift (Refereegranskat)
  • 131. Engquist, I.
    et al.
    Liedberg, B.
    Lestelius, Magnus
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Paper Surface Centre. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Materialvetenskap.
    Hydrogen Bond Interaction between Ester Terminated Self-Assembled Monolayers and Adsorbed Water Molecules and Its Implications for Cluster Formation1995Ingår i: Journal of Physical Chemistry, Vol. vol 99, s. 14198-14200Artikel i tidskrift (Refereegranskat)
  • 132.
    Engström, Gunnar
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Causes of back-trap mottle in lithographic offset prints on coated papers2016Ingår i: TAPPI Journal, ISSN 0734-1415, Vol. 15, nr 2, s. 91-101Artikel i tidskrift (Refereegranskat)
    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.

  • 133.
    Enmark, Martin
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Fundamental Investigations of Supercritical Fluid Chromatography2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    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.

  • 134.
    Enmark, Martin
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Asberg, Dennis
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (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
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Fornstedt, Torgny
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Evaluation of scale-up from analytical to preparative supercritical fluid chromatography2015Ingår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1425, s. 280-286Artikel i tidskrift (Refereegranskat)
    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.

  • 135.
    Enmark, Martin
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörsvetenskap och fysik (from 2013).
    Glenne, Emelie
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Leśko, Marek
    Rzeszów University of Technology, Poland.
    Langborg Weinmann, Annika
    AstraZeneca.
    Leek, Tomas
    AstraZeneca.
    Kaczmarski, Krzysztof
    AstraZeneca.
    Klarqvist, Magnus
    AstraZeneca.
    Samuelsson, Jörgen
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Fornstedt, Torgny
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Investigation of robustness for supercritical fluid chromatography separation of peptides: Isocratic vs gradient mode2018Ingår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1568, s. 177-187Artikel i tidskrift (Refereegranskat)
    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.

  • 136. Eriksson, U.
    et al.
    Järnström, Lars
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Paper Surface Centre. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Materialvetenskap.
    Engström, G.
    Rigdahl, M.
    Strukturelle und rheologische Unterschiede zwischen CMC- und stärkehaltigen Streichfarben auf Kaolinbasis1991Ingår i: PTS-Streicherei Symp., PTS-Vortragsband Nr. 02/91, 97 (1991), 1991Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 137. Eriksson, U.
    et al.
    Järnström, Lars
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Paper Surface Centre. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Materialvetenskap.
    Engström, Gunnar
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Paper Surface Centre.
    Rigdahl, M.
    Strukturelle und rheologische Unterschiede zwischen CMC- und stärkehaltigen Streichfarben auf Kaolinbasis1991Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
  • 138.
    Fadhel, Zainab
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013).
    Stroke-induced stem cells proliferation in normal versus diabetic mice and pharmacological regulation2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Introduction: Stroke is caused from the occlusion of any cerebral artery leading to cerebral ischemia, brain damage and consequent neurological impairments and disability. The primary causes of mortality in western populations is stroke. Diabetes type 2 is a high risk factor for stroke. Stroke leads to an observable increase of neural stem cell proliferation in the subventricular zone and enhances neurogenesis in the adult rodent and human brain which suggest a mechanism contributing to stroke recovery. Neurogenesis in type 2 diabetes patients is impaired. However, whether stroke-induced neurogenesis is impaired in diabetes has not been studied. Exendin-4 is a drug for clinical treatment of type 2 diabetes which has been shown to have neuroprotective properties in animal studies. However whether Exendine-4 leads to increased neurogenesis after  stroke in the diabetic brain has not been previously studied.

     Aims: The specific aims of this project were to determine whether stroke-induced stem cell proliferation is impacted by diabetes in the mouse, and if Exendine-4 regulates stroke-induced stem cell proliferation in normal and diabetic mice.

    Material and Methods: Aged obese/type 2 diabetic mice were subjected to stroke. The Exendin-4 treatment was started 1.5 hours thereafter. Treatment was continued for one week before animals were sacrificed. Brains were isolated and the neurons were immunostained using the specific proliferation marker Ki67. Neural stem cell proliferation was quantified by counting Ki67+ cells in the ipsilateral (subventricular zone in stroke hemisphere).The estimation was assessed by stereological counts of proliferating stem cell in the subventricular zone.

     Results: The number of proliferating stem cell after stroke was statistically significantly higher in the normal mice versus diabetic mice. The effect was present in both sides (control and stroke) of the subventricular zone. Exendine-4 treatment induced statistically significant increased of  stem cell proliferation in normal mice but not in diabetic mice.

     

    Conclusions: The result of this study shows that type 2 diabetes decreased the proliferation of neural stem cell in the subventricular zone and that Exendin-4 enhanced the subventricular proliferation in a preclinical model of clinical relevance. The data suggest that the Exendin-4 treatment could be administered to normal patients suffering from stroke in the ambulance or in the emergency room although more studies are needed. 

  • 139. Farooq, Muhammad
    et al.
    Hamayoun, Ahsan
    Naqvi, Muhammad
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Nawaz, Saad
    Usman, M
    Naqvi, SR
    Imran, M
    Nadeem, Rida
    Raza, Allah
    Turan, A
    Pettinau, A
    Andersen, A
    Thermodynamic Performance Analysis of Hydrofluoroolefins (HFO) Refrigerants in Commercial Air-Conditioning Systems for Sustainable Environment2020Ingår i: Processes, ISSN 2227-9717Artikel i tidskrift (Refereegranskat)
  • 140. Fogden, Andrew
    et al.
    Ström, Göran
    Järnström, Lars
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Paper Surface Centre. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Materialvetenskap.
    Fokus på ytan2004Ingår i: SPCI Sv. Papperstidning nr 12/2004Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 141.
    Fornstedt, Torgny
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Introduction to "Fundamental challenges and opportunities for preparative supercritical fluid chromatography by G. Guiochon, A. Tarafder [J. Chromatogr. A 1218 (2011) 1037-1114]"2016Ingår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1446, s. 19-20Artikel i tidskrift (Övrigt vetenskapligt)
  • 142.
    Fornstedt, Torgny
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Modern supercritical fluid chromatography: Possibilities and pitfalls2015Ingår i: LC GC Europe, ISSN 1471-6577, Vol. 33, nr 3, s. 166-174Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There has been a revival of supercritical fluid chromatography (SFC) in recent years, especially in the chiral preparative field, but also more recently in the analytical area. However, SFC is considerably more complex than liquid chromatography (LC), mainly because of the compressibility of the mobile phase. One can say that SFC is a "€rubber variant of LC where everything considered constant in LC varies in SFC. In this review, we go through advances in theory, instrumentation, and novel applications.

  • 143.
    Fornstedt, Torgny
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Forssén, Patrik
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Samuelsson, Jörgen
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Modeling of Preparative Liquid Chromatography2013Ingår i: Liquid Chromatography: Fundamentals and Instrumentation / [ed] Salvatore Fanali, Paul R. Haddad; Poole, Colin; Schoenmakers, Peter; Lloyd, David K., Elsevier, 2013, s. 407-425Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Abstract Preparative chromatography is today the best generic method for the purification of small drugs and valuable chemical components at the <10 kg-level. Recent progress in computer technology and the development of new nonchiral and chiral stationary phases, as well as numerous improvements in reliability and economic performance, have considerably increased the interest in modeling in academic and industrial communities. This chapter serves as an introduction to the field of modeling preparative liquid chromatography in the classical batch mode, aiming at improved process purification of valuable chemical components, drugs, and chiral components. We go through the most important column and adsorption models and methods for determination of the essential thermodynamic adsorption data for both column characterization and process improvement. But, we also cover important operational conditions sometimes neglected in the modeling procedure, such as the impact of injection profiles and accounting for the additive in the modeling procedure.

  • 144.
    Fornstedt, Torgny
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Forssén, Patrik
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Westerlund, Douglas
    Dept Med Chem, Analyt Pharmaceut Chem, POB 574, SE-75123 Uppsala, Sweden..
    System peaks and their impact in liquid chromatography2016Ingår i: TrAC. Trends in analytical chemistry, ISSN 0165-9936, E-ISSN 1879-3142, Vol. 81, s. 42-50Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    A sample injected into a chromatographic system can generate extra peaks, called "system peaks", which in general are undetectable. However, for small analytical injections, solute zones eluting with a system zone will often give strongly deformed solute peaks. But, if a solute zone is eluted in a particular region of the system zone it will instead be strongly compressed and well-shaped. For overloaded solute injections, another type of complex band deformation may take place due to large system peaks. This review will present results related to system peak distortions of both small analytical peaks and large preparative ones. Guidelines will be given on how to avoid unwanted distortions and how to utilize the distortions for increased detectability in analytical chromatography, or enhanced production rate in preparative chromatography. The works reviewed here were mainly made by Georges Guiochon, and some of his close colleagues, and is dedicated to his memory. 

  • 145.
    Forssen, Patrik
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Fornstedt, Torgny
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    A model free method for estimation of complicated adsorption isotherms in liquid chromatography2015Ingår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1409, s. 108-115Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Here we show that even extremely small variations in the adsorption isotherm can have a tremendous effect on the shape of the overloaded elution profiles and that the earlier in the adsorption isotherms the variation take place, the larger its impact on the shape of the elution profile. These variations are so small that they can be "hidden" by the discretization and in the general experimental noise when using traditional experimental methods, such as frontal analysis, to measure adsorption isotherms. But as the effects of these variations are more clearly visible in the elution profiles, the Inverse Method (IM) of adsorption isotherm estimation is an option. However, IM usually requires that one selects an adsorption isotherm model prior to the estimation process. Here we show that even complicated models might not be able to estimate the adsorption isotherms with multiple inflection points that small variations might give rise to. We therefore developed a modified IM that, instead of fixed adsorption isotherm models, uses monotone piecewise interpolation. We first validated the method with synthetic data and showed that it can be used to estimate an adsorption isotherm, which accurately predicts an extremely "strange" elution profile. For this case it was impossible to estimate the adsorption isotherm using IM with a fixed adsorption model. Finally, we will give an example of a real chromatographic system where adsorption isotherm with inflection points is estimated by the modified IM.

  • 146.
    Forssén, Patrik
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap.
    Samuelsson, Jörgen
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap.
    Fornstedt, Torgny
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap.
    Relative importance of column and adsorption parameters on the productivity in preparative liquid chromatography. I: Investigation of a chiral separation system2013Ingår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1299, s. 58-63Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Starting out from an experimental chiral separation system we have used computer simulations for a systematic investigation on how the maximum productivity depends on changes in column length, packing particle size, column efficiency, back pressure, sample concentration/solubility, selectivity, retention factor of the first eluting component and monolayer saturation capacity. The study was performed by changing these parameters, one at a time, and then calculating the corresponding change in maximum productivity. The three most important parameters for maximum production rate was found to be (i) the selectivity (ii) the retention factor of the first eluting component and (iii) the column length. Surprisingly, the column efficiency and sample concentration/solubility were of minor importance. These findings can be used as rough guidelines for column selection, e.g. a low-efficiency column are more likely perform better, in terms of productivity, than a high-efficiency column that have higher retention factor for the first eluting component.

  • 147.
    Fredriksson, Robert
    et al.
    AkzoNobel , Separations Products, Bohus, Sweden.
    Samuelsson, Jörgen
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Fornstedt, Torgny
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    The Importance of Overloading Studies in Method Development: A Case Study2012Konferensbidrag (Refereegranskat)
  • 148.
    Frodeson, Stefan
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013). Environmental and Energy Systems.
    Linden, Pär
    Wallenberg Wood Science Centre, Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
    Henriksson, Gunnar
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Berghel, Jonas
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Compression of Biomass Substances—A Study on Springback Effects and Color Formation in Pellet Manufacture2019Ingår i: Applied Science, E-ISSN 2076-3417, Vol. 9, nr 20, artikel-id 4302Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to increase the use of a variated raw material base for pellet production with a maintained density level, knowledge of the biomaterials’ ability to counteract any springback effects is essential. In this study, the springback effects were investigated for single press produced pellets from cellulose, hemicelluloses, pectin, and two woods at different moisture contents. The change in pellet coloring was also tested through a spectrophotometer for both xylan and carboxymethyl cellulose (CMC) pellets. The results show that the density of xylan pellets is much higher than glucomannan, for both green and cured pellets, and that the length of the pellets, as well as springback contribution, differ between the hemicelluloses. The study also presents results showing that both xylan and CMC pellets have a mutually identical spectrum and that the changes in the structure of xylan are not only related to moisture content, but are also pressure-related. The study also postulates that the color difference of the xylan pellets is a result of physical changes in the structure, as opposed to being of a chemical nature.

  • 149.
    George, Zandra
    et al.
    Chalmers, Dept Chem & Chem Engn, SE-41296 Gothenburg, Sweden..
    Xia, Yuxin
    Linkoping Univ, IFM, Biomol & Organ Elect, SE-58183 Linkoping, Sweden.;Linkoping Univ, Ctr Organ Elect, SE-58183 Linkoping, Sweden..
    Sharma, Anirudh
    Univ S Australia, Future Ind Inst, Mawson Lakes, SA 5095292, Australia..
    Lindqvist, Camilla
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörsvetenskap och fysik (from 2013).
    Andersson, Gunther
    Flinders Univ S Australia, Flinders Ctr NanoScale Sci & Technol, Sturt Rd,Bedford Pk, Adelaide, SA 5042, Australia..
    Inganas, Olle
    Linkoping Univ, IFM, Biomol & Organ Elect, SE-58183 Linkoping, Sweden.;Linkoping Univ, Ctr Organ Elect, SE-58183 Linkoping, Sweden..
    Moons, Ellen
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörsvetenskap och fysik (from 2013).
    Muller, Christian
    Chalmers, Dept Chem & Chem Engn, SE-41296 Gothenburg, Sweden..
    Andersson, Mats R.
    Chalmers, Dept Chem & Chem Engn, SE-41296 Gothenburg, Sweden.;Univ S Australia, Future Ind Inst, Mawson Lakes, SA 5095292, Australia..
    Two-in-one: Cathode modification and improved solar cell blend stability through addition of modified fullerenes2016Ingår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 4, nr 7, s. 2663-2669Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The synthesis of dual purpose modified fullerenes with pyridine-as well as amine-functional groups is reported. Addition of these fullerenes to a polymer : fullerene bulk-heterojunction blend based on a thiophene-quinoxaline donor polymer is found to modify the active layer/cathode interface of inverted solar cells (glass/ITO/active layer/MoO3/Al). In particular the open-circuit voltage of devices is increased from 0.1 V to about 0.7 V, which results in a drastic rise in photovoltaic performance with a power conversion efficiency of up to 3%. At the same time, presence of the functionalised fullerene additives prevents the detrimental formation of micrometre-sized fullerene crystals upon annealing at 140 degrees C. As a result, the device performance is retained, which promises significantly increased thermal stability of the bulk-heterojunction blend nanostructure.

  • 150.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Aspects on the reactivity of pulps prior to viscose preparation2012Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 243Artikel i tidskrift (Övrigt vetenskapligt)
1234567 101 - 150 av 825
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