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  • 51.
    Bergman, Helene
    et al.
    Karlstads universitet, Institutionen för kemi.
    Gillstedt, Anna
    Karlstads universitet, Institutionen för kemi.
    Tungmetallbalans över Gruvöns bruk2002Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
  • 52.
    Bergström, Jens
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Materialvetenskap. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för maskin- och materialteknik.
    Fredriksson, Gunnel
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för maskin- och materialteknik. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Materialvetenskap.
    Johansson, M
    Kotik, Ouliana
    Thuvander, Fredrik
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Paper Surface Centre. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Materialvetenskap. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för maskin- och materialteknik.
    The Use of Tool Steels: Experience and Research2002Bok (Refereegranskat)
  • 53. Bergström, L.
    et al.
    Sjöberg, M.
    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.
    Concentrated Kaolinite Suspensions - Polymer Adsorption and Rheological Properties1996Ingår i: in "Science of Whitewares", ed. by V.E. Henkes, G.Y. Onoda and W.M. Carty, American Ceramic Society, Westerville, OH, 1996, pp. 65-77 / [ed] V.E. Henkes, G.Y. Onoda and W.M. Carty, 1996Kapitel i bok, del av antologi (Refereegranskat)
  • 54. Bjorklund, R.B.
    et al.
    Arwin, H.
    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.
    Adsorption of Anionic and Cationic Polymers on Porous and Non-Porous Calcium Carbonate Surfaces1994Ingår i: Appl.Surf.Sci.,75,197(1994)Artikel i tidskrift (Refereegranskat)
  • 55. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Basta, Jiri
    Effect of cooking conditions on ECF bleaching and brightness reversion of birch kraft pulp2005Ingår i: Tappi JournalArtikel i tidskrift (Refereegranskat)
  • 56. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Basta, Jiri
    Formation of AOX and OCI in ECF-bleaching of birch pulp2004Ingår i: Tappi Journal 3(2004)8, 7-11Artikel i tidskrift (Refereegranskat)
  • 57. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Basta, Jiri
    Formation of AOX and OCl in ECF-bleaching of birch pulp2004Ingår i: Tappi Journal, Vol. vol 3 no 8Artikel i tidskrift (Refereegranskat)
  • 58. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Basta, Jiri
    The influence of softwood kraft cooking conditions on the brightness development in ECF- bleaching2004Ingår i: Appita Journal, Vol. vol 57 no 3Artikel i tidskrift (Refereegranskat)
  • 59. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Basta, Jiri
    The influence of softwood kraft cooking conditions on the brightness development in ECF- bleaching2003Konferensbidrag (Refereegranskat)
  • 60. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Jour, Pia
    Forsström, Ann-Britt
    AOX formation in ECF bleaching at different kappa numbers ' influence of oxygen delignification and hexenuronic acid content2001Konferensbidrag (Refereegranskat)
  • 61. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Jour, Pia
    Forsström, Ann-Britt
    AOX formation in ECF bleaching at different kappa numbers: Influence of oxygen delignification and hexenuronic acid content2002Ingår i: Tappi Journal, 1(2002)7, 20-24, Vol. vol 1 no 7Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    he aim of this study was to determine how oxygen delignification before bleaching and the hexenuronic acid (HexA) content of the pulps influenced the acisorbable organic halogen (AOX) formation in the elemental chlorine free (ECP) bleaching effluent. Softwood industrial chips cooked to different kappa numbers were oxygen defignified, treated in a hot acid stage (A*), or not pretreated at all before ECF bleaching. We compared the AOX levels in the ECF effluents from bleaching of these pulps. There was a higher formation of AOX for oxygen delignified pulps than for non-oxygen delignified pulps compared at the same kappa number before ECF bleaching. The hexenuronic acid (HexA) content of the pulps had a major impact on the AOX levels in the D[0] effluent. The oxygen delignified pulps had a higher HexA content than the non-oxygen delignified pulps compared at the same kappa number. This explains the higher AOX formation from oxygen delignified pulps. The AOX originating from HexA was not stable upon storage. Application, This study gives additional insight on the AOX formation in ECF bleaching. The information may be used to take appropriate measures when addressing environmental issues

  • 62. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Jour, Pia
    Forsström, AnnBritt
    TCF and ECF bleaching effluent COD at varying kappa numbers after cooking2003Ingår i: Appita Journal, Vol. vol 56 no 3Artikel i tidskrift (Refereegranskat)
  • 63. Björklund, Magnus
    et al.
    Germgård, Ulf
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Jour, Pia
    Forsström, AnnBritt
    TCF and ECF bleaching effluent COD at varying kappa numbers after cooking2003Ingår i: Appita Journal 56(2003)3, 200-205Artikel i tidskrift (Refereegranskat)
  • 64.
    Bohlin, Erik
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Optics of coated paperboard: Aspects of surface treatment on porous structures2010Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Calendering of coated and uncoated paper is widely used to enhance optical properties such as gloss and print quality. The aim of this thesis is to characterize coatings and prints, and to validate models using experimental results from optical measurements of physical samples.

    Calendering of coated paper often leads to a brightness decrease. The mechanism for this is not altogether clear. One common explanation is that the porosity of the coating layer decreases and hence the scattering decreases. By comparing simulated and measured results it was shown that modifications of the surface properties account for the brightness decrease of ground calcium carbonate coated substrates with calendering. Monte Carlo light scattering simulations, taking into account the measured decrease of surface microroughness and increased effective refractive index, showed that surface modifications accounted for most of the observed brightness decrease of the ground calcium carbonate coated substrate, whereas the bulk scattering and absorption coefficients were not affected by calendering. It was also shown that the scattering coefficient is significantly dependent on the coat weight whereas the physical absorption coefficient is not.

    The penetration of ink in the z-direction of a substrate influences the quality of the print. The ink penetration affects print density, mottling and dot gain, common print effects that influence the preference of consumers. The pressure in the printing nip and the porosity of the substrate both affect the amount of ink that is pressed into the porous structure of a coating layer during printing. By printing pilot coated paperboard with different coating porosity and measuring the resulting optical properties of the prints, a basis for simulations of the different layers, that is to say the coating, the print and the mixed layer in between, was created. Results show that ink distribution is strongly affected by the roughness of the substrate. Fibres and fibre flocks underneath the two coating layers created an unevenly distributed coating thickness that affected the print quality. Differences in pore size and pore size distribution also affected the behaviour of the ink. A coating layer of broad pigment particle size distribution resulted in a relatively low print density, in comparison to coatings of narrowly distributed particle sizes. Comparison of dot gain showed that the coating layer of a narrow particle size distribution had a relatively low dot gain compared to others. In this work, these results are explained by the differences in ink distributions on and in the coating layers.

  • 65.
    Bohlin, Erik
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Coppel, Ludovic
    Innventia AB, Stockholm, Sweden.
    Andersson, Caisa
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Edström, Per
    Mid Sweden University.
    Characterization and modelling of the effect of calendering on coated polyester film2009Ingår i: Advances in Printing and Media Technology: Vol XXXVI, 2009, s. 301-308Konferensbidrag (Refereegranskat)
    Abstract [en]

    Polyester films were coated with a coating colour based on a ground calcium carbonate with narrow particle size distribution. Four different coat weights were produced. The coated sheets were calendered and the samples were exposed to up to twenty nips in the calender at a line load of 300 kN/m at 50°C. The brightness and the thickness were measured after each calendering nip. Reflectometry was used to measure the refractive index and the microroughness of the samples. Calendering lead to a decrease of the Kubelka-Munk scattering coefficient and an increase of the absorption coefficient of the coated transparent films. Taking into account non-uniform surface reflection at the boundaries between media of different refractive indices, a large part of the reflectance decrease due to calendering could be attributed to an increase of the effective refractive index at the coating surface and a decrease of the surface microroughness.

  • 66.
    Bohlin, Erik
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Coppel, Ludovic
    Innventia AB, Stockholm, Sweden.
    Johansson, Caisa
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Edström, Per
    Mid Sweden University.
    Modelling of Brightness Decrease of Coated Cartonboard as an Effect on Calendering: Microroughness and Effective Refractive Index Aspects2010Ingår i: TAPPI 11th Advanced Coating Fundamentals Symposium, Munich, Germany, 2010: Symposium Proceedings, Norcross, GA, USA: TAPPI Press, 2010, s. 51-65Konferensbidrag (Refereegranskat)
    Abstract [en]

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

  • 67.
    Bohlin, Erik
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper, Paper Surface Centre.
    Johansson, Caisa
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper, Paper Surface Centre.
    Lestelius, Magnus
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper, Paper Surface Centre.
    Evaluation of ink penetration in porous coatings2012Konferensbidrag (Refereegranskat)
  • 68.
    Bohlin, Erik
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper, Paper Surface Centre.
    Johansson, Caisa
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper, Paper Surface Centre.
    Lestelius, Magnus
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper, Paper Surface Centre.
    Flexographic ink-coating interactions: effects of kaolin clay/GCCblends in coating layers2014Konferensbidrag (Refereegranskat)
  • 69.
    Bohlin, Erik
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Johansson, Caisa
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Lestelius, Magnus
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Flexographic Ink-Coating Interactions, Effects of Porous Structure Variation of Coated Paperboard2012Konferensbidrag (Refereegranskat)
  • 70.
    Boström, Charlotta
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap.
    Rosén, Anna
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap.
    Fibre-to-Board - Validation of the Simulation Model and Development of Laboratory Methods to Receive Input Data2006Självständigt arbete på grundnivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [sv]

    Fibre to board är en simulerings modell framtagen vid Stora Enso Research Centre Karlstad. Modellen används för att prediktera krympning och styrkeegenskaper hos en bestämd kartongbana. Indata till modellen hämtas ifrån isotropa laboratorieark. För att förbättra och verifiera erhållna resultat från simuleringsmodellen så att de korresponderar bättre med värden från kartongmaskinen fanns det ett önskemål från RCK om att undersöka möjligheten att optimera indata till modellen.

    Laboratoriearktillverkning enligt standard resulterar alltid i ark med egenskaper som ligger långt från maskin arkens. Därför är syftet med detta examensarbete att modifiera arktillverkningsmetoden så att laboratorieark med egenskaper närmare de för maskinark kan erhållas. För att lyckas med detta undersöktes det hur olika parametrar påverkar pappersegenskaperna och om tillverkningsmetoden kunde förbättras.

    Vid undersökning av fritorkade ark upptäcktes att ark som pressats med viraduk mellan läskark och laboratorieark blev mindre buckliga än ark som pressats med enbart läskark. Dessa ark hade också en något högre densitet. Buckligheten som är en följd av krympningen reducerades också när arken torkades mellan viraduk under lätt belastning. Läskarkens inverkan på de isotropa arken kunde inte elimineras genom att använda viraduk vid pressning, inte heller genom att växla läskarken så att deras MD riktning orienterades olika.

    Även finmaterialets inverkan på pappersegenskaperna undersöktes. Resultaten visade att ett ökat finmaterial innehåll ger ökad krympning, högre densitet, ökat dragstyvhetsindex, buckligare ark och en minskad luft permeabilitet.

    Det visade sig att olika presstryck ger arken en högre densitet men krympningen påverkades inte märkbart. Densitet i samma nivå som på maskinark kunde däremot inte erhållas med laboratorieplanpress. Detta kan bero på att fibrerna i fritorkade ark relaxerar efter pressning, vilket ger en lägre densitet. För att kunna få högre densitet kanske en annan press än den planpress som användes i dessa studier kan införas. Det kunde även konstateras att ett ökat presstryck ger mindre buckliga ark.

    I dessa studier, där ark tillverkades av färdiga skiktblandningar från maskinkar, hade inte ytvikten på arken någon större inverkan på krympningen. Detta tyder på att ytvikten på arken som används som indata inte har så stor inverkan vid simulering i modellen Fibre-to-board.

    Det undersöktes även hur skikten i ett två-skikts ark och en blandning av LF/CTMP massa påverkar krympningen. Resultaten visade att krympningen ökar med en högre andel LF och att det finns ett linjärt samband mellan den totala krympningen för en blandning av LF/CTMP massa och krympningen för de enskilda massorna.

    För att kunna verifiera beräkningsmodellen Fibre-to-board utfördes slutligen en simulering. Skiktblandningar och tvärsprofiler från kartong togs ut från en specifik pappers maskin inom Stora Enso koncernen. Egenskaperna på laboratorieark gjorda av skiktblandningarna användes som indata till simuleringsprogrammet och kartongprofilerna från pappersmaskinen användes som referens. Dragstyvhetsindex i CD stämde bra överens med de mätningar som gjordes på maskinarken, men dragstyvhetsindex i MD skiljde sig. Krympningen som beräknades på maskinarken överensstämde inte med det simulerade resultatet. Det förekommer en osäkerhet i krympmätningarna som gjordes på kartong profilerna, då det idag inte förekommer någon mätutrustning på pappersmaskinen, som bestämmer bredden mellan press- och torkpartiet. Detta komplicerar valideringen av Fibre-to-board modellen.

  • 71.
    Boudreau, Jonna
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    A close-up on Yankee coating - for better control2007Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
  • 72.
    Boudreau, Jonna
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Improvement of the tissue manufacturing process2009Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The creping process and the conditions on the Yankee cylinder are the key factors in the production process. They need to be kept under good control in order to maintain a high and uniform quality. A natural coating always develops on the surface of the Yankee cylinder due to evaporation from dissolved and dispersed substances and to fiber fragments that remain on the surface after creping. Nevertheless, coating chemicals are sprayed onto the Yankee surface in order to modify the adhesion between the paper and the dryer cylinder. To be able to control the process, on-line measurements of coating thickness as well as of the crepe structure of the tissue paper produced would be very valuable. In the work described in this thesis, the coating layer was analyzed chemically and morphologically to provide information about the coating layer before starting any on-line measurements. The chemicals added and the constituents of the pulps are known to the paper producers, but what is left on the cylinder and whether there are different layers of coating still remain to be investigated. The chemical analysis indicated that the adhesive content was higher in an inner layer of the coating than in the outer layer. The relative amount of polyamide-amine resin calculated on the basis of the nominal nitrogen content in the resin was low indicating that the coating consisted of a significant amount of carbohydrates or other substances. The coating layer could not be considered transparent. It was observed that the coating was thick and appeared patch-wise and that it contained fiber fragments. Measurements on a laboratory scale, to further be applied on-line on the tissue machine, have been investigated and evaluated in this study. The thickness of the coating layer on a laboratory dryer has been measured. The method was based on fluorescence with an optical brightener added to the coating chemicals sprayed on the Yankee dryer. With a UV-LED (Ultra Violet - Light Emitting Diode) the coating layer was exposed to UV-light and the intensity of the light emitted by the optical brightener in the layer was measured. The intensity in the trials with different thickness of the coating and no coating was scattered and no trend could be seen between the different trial points. Attempts were made to measure the wavelength of the tissue paper produced with an optical fiber perpendicular to and at an angle to the paper surface. The paper was travelling in a slow speed while the measurements were made. The collected signal to noise ratio was low and it was not possible to detect any representative characteristic wavelength of the tissue.

  • 73.
    Boudreau, Jonna
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Barbier, Christophe
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Laboratory creping equipment2014Ingår i: Journal of Adhesion Science and Technology, ISSN 0169-4243, E-ISSN 1568-5616, Vol. 28, nr 6, s. 561-572Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Tissue production is largely dependent on the creping process as creping influences the paper properties and thus the quality of the end product and the runnability of the tissue machine. The process is very complex and includes numerous variables affecting the adhesion, and ultimately the creping of the tissue paper. To perform experiments on a full scale machine, or even a pilot machine, is very costly, therefore a laboratory scale creping device is demanded, able to replicate conditions encountered on a tissue machine. In this paper new laboratory testing equipment is developed, whereby the adhesion between paper and metal surfaces (when scraping off the paper with configurations similar to the industrial process) can be studied. A new method to adhere paper to metal, used in the new laboratory creping equipment, is also developed. To evaluate the equipment, different creping angles were tested. The scraping tests show a trend in decreasing creping force for an increasing creping angle.

  • 74.
    Boudreau, Jonna
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Beghello, Luciano
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    A Method of Measuring the Thickness of the Coating on a Dryer Cylinder2009Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 24, nr 3, s. 309-312Artikel i tidskrift (Refereegranskat)
  • 75.
    Boudreau, Jonna
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Beghello, Luciano
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Experiments to Find Online Measurements of the Structure of the Tissue Paper SurfaceManuskript (Övrig (populärvetenskap, debatt, mm))
  • 76.
    Boudreau, Jonna
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Hollmark, Holger
    Hollmark Imptec AB.
    Beghello, Luciano
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Chemical and Morphological Analyses of the Tissue Yankee Coating2009Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 24, nr 1, s. 52-59Artikel i tidskrift (Refereegranskat)
  • 77.
    Boudreau, Jonna
    et al.
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Hollmark, Holger
    Beghello, Luciano
    Method for analyzing cylinder coating on tissue machines2008Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    Samples of coating have been taken at different positions on a running Yankee cylinder

    to analyze the content. The scrapings of the coating were obtained by collecting material

    from the cleaning doctor and by scraping coating with a hand scraper in between the

    cleaning doctor and the spray boom. The conditions on the Yankee dryer surface were

    varied by varying specific creping additives. Chemical and morphological analyses were

    made on the samples. The chemical analysis comprised carbohydrate analysis and

    nitrogen analysis. Analyses of the scrapings were compared with analyses of the creped

    paper. Replicas of the coating layer were made with a silicon rubber to show the

    microstructure. The coating was thick and appeared patch-wise and it contained fiber

    fragments. The chemical analysis indicates that the nitrogen content was higher for the

    coating close to the cylinder. The sampling method seems to work well, since the

    nitrogen content increases with an increased amount of applied adhesive

  • 78.
    Brandén, Carl-Magnus
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Determination of the Degree of Oxidation in Dialdehyde Cellulose Using Near Infrared Spectroscopy2017Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The purpose of this thesis work was to investigate possible in-, on- or at-line methods to determine the degree of oxidation in dialdehyde cellulose. Several technologies were reviewed which led to a feasibility study into a possible on-line or at-line method using near infrared spectroscopy for determining the degree of oxidation in wet dialdehyde cellulose. A calibration model was built using the near infrared spectra of 19 samples created from kraft pulp with a degree of oxidation between 0 and 52.1 %. The obtained model uses five significant principal components and has a goodness of fit (R2) of 0.998 and a goodness ofprediction (Q2) of 0.991. The first principal component describes the degree of oxidation and the second the water content. A validation set of six samples was used to test the model and the predicted values resulted in a root mean square error of prediction of 0.85 in comparison with the reference method which had a pooled standard deviation of 0.69.

  • 79. Breen, Chris
    et al.
    Johansson, Caisa
    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.
    Thompson, Simon
    Black, Leon
    Järnström, Lars
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Paper Surface Centre.
    Using clays to enhance the barrier properties of sustainable paper coatings2008Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
  • 80.
    Broström, Cecilia
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Methods for preparation of oxygen scavenging films containing laccase and lignosulfonates2012Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
  • 81.
    Brånn, Daniel
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap.
    Simulering av valkar i pappersrullar: och analys av de slappa stråk som uppkommer2008Självständigt arbete på grundnivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [sv]

    Då en pappersrulle har partier där pappret är längre kallas det ibland för slappa stråk. Det finns flera orsaker till slappa stråk och en av dessa orsaker är att pappret har en ojämn tjockleksprofil. I dessa fall uppstår de slappa stråken eftersom den ojämna tjockleksprofilen gör att pappersrullen på de positioner där pappret är tjockare får en större diameter än i övrigt. Då papper rullas över dessa åsar eller valkar som har en större diameter töjs pappret ut och då det rullas av rullen är det slappt. Körbarhetsproblem till följd av att pappret är slappt i vissa partier är ett stort problem inom pappersindustrin. Dessa körbarhetsproblem kan t.ex. vara att det uppstår veck i pappret då det passerar valsnyp.

    I detta projekt har slappa stråk skapats genom att en viss mängd plast rullats in i pappersrullar dels i botten, dels i mitten samt ett parti närmast rullens periferi. Banspänningsmätningar har utförts för att se hur slappt pappret blivit där plast rullats in. För att se om pappret fått bestående längdskillnader i de slappa stråken har tvärsbanor tagits ur rullen och varje tvärsbana delats upp i remsor för att mäta längden på. Även andra pappersegenskaper har testats i dessa partier för att se om de slappa stråken påverkar papprets egenskaper. Bland annat har tjockleksprofilen mätts upp för att se om pappret komprimerats och fått en bestående densitetsökning i de slappa stråken. Mätningar visar dels att pappret blir slappt i partier där plast rullats in, men också att pappret efter några dagar i stort sätt helt återgått till sin ursprungstjocklek och vissa fall även i längdled. Pappret var som slappast i botten av rullarna och där uppmättes relativt stora längdskillnader även om pappret troligtvis återhämtat sig till en stor del även där.

  • 82. Calvert, D.J.
    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.
    Sundin, M.
    Larsson, A.
    Dynamic Test Procedures to Evaluate Runnability of Water-Based PSAs: Contact Angle Measurements under Non-Equilibrium Conditions1996Ingår i: Eur.Adhesives Sealants,June,2&4-5(1996)Artikel i tidskrift (Refereegranskat)
  • 83.
    Carlsson, Gunilla
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Axrup, Lars
    Stora Enso, Karlstad Res Ctr, SE-65009 Karlstad, Sweden.
    Ljungqvist, Carl-Henrik
    Stora Enso, Karlstad Res Ctr, SE-65009 Karlstad, Sweden..
    Nyflott, Asa
    Stora Enso, Karlstad Res Ctr, SE-65009 Karlstad, Sweden.;Karlstad Univ, SE-65188 Karlstad, Sweden..
    The use of fluorescence microscopy and image analysis to characterize the porous structure in micro fibrillar cellulose gel - Part I: Brownian motion2013Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 28, nr 2, s. 190-197Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The porous structure of a micro fibrilar cellulose, MFC, gel was studied by fluorescence microscopy and image analysis. The Brownian motion of fluorescent labelled carboxylated latex spheres, probes, was investigated at both high, 0.1-5 wt%, and low, 0-20 ppm, concentrations of MFC. The developed tracking program provides trajectories for probes. The trajectories can be studied according to either the individual approach or the ensemble approach to give complementary information regarding the fibrilar system. The Brownian motion can be used in the range 0 to 1.0 wt% MFC and the percentage of idle probes can be used when the concentrations exceeds 1.0 wt% MFC. The Brownian motion was found to be pH dependent both for the low and the high concentration regimes.

  • 84.
    Carlsson, Gunilla
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Paper Surface Centre. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Materialvetenskap.
    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.
    van Stam, Jan
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap. Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Materialvetenskap.
    Latex Diffusion at High Volume Fractions Studied by Fluorescence Microscopy2006Ingår i: J. Colloid Interface Sci. 298(1), 162-171 (2006)Artikel i tidskrift (Refereegranskat)
  • 85. Carlsson, Roger
    Effect of Latex Viscoelasticity on Strenght Developement and Calendar Runnability in Coated Paper and Board Production2005Licentiatavhandling, monografi (Övrigt vetenskapligt)
  • 86.
    Christophliemk, Hanna
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Johansson, Caisa
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Ullsten, Henrik
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Järnström, Lars
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Oxygen and water vapor transmission rates of starch-poly(vinyl alcohol) barrier coatings for flexible packaging paper2017Ingår i: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 113, s. 218-224Artikel i tidskrift (Refereegranskat)
    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.

  • 87.
    Christophliemk, Hanna
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Ullsten, Henrik
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Johansson, Caisa
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper, 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.
    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 drawbacks2011Konferensbidrag (Övrigt vetenskapligt)
  • 88.
    Christophliemk, Hanna
    et al.
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Ullsten, Henrik
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Johansson, Caisa
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Järnström, Lars
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper (from 2013).
    Starch-poly(vinyl alcohol) barrier coatings for flexible packaging paper and their effects of phase interactions2017Ingår i: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 111, s. 13-22Artikel i tidskrift (Refereegranskat)
    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

  • 89.
    Dahlin, Per
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörs- och kemivetenskaper.
    Na/S balances at Skoghall mill 2015: Balances after reconstruction of the fiber line2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    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.

  • 90.
    Dahlman, Niclas
    Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
    Near Infrared Spectroscopy: An Introductory Study On Measurement Techniques And Tools For Analysing Moisture Content In Pulp And Paper Media2012Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The growing technique of near infrared spectroscopy is used to build fundamental knowledge of how the method might be applied for moisture determination in pulp and paper media. Filter paper was used to investigate the angle and distance dependence, otherwise obscured by the uneven surface of pulp or dry fibers. For contact measurements both filter paper and CTMP-fibers were used. The angle and distance evaluation is based on visual spectral interpretation to later incorporate preprocessing methods of the data followed by a multivariate analysis using PLS. With the knowledge built before the experimental startup, the acquired spectra are known to have many co-linearities and hence, for the purpose of determining the moisture content abundant information which might enable the reduction of data points for evaluation. The distance and angle experiments gave results indicating that the intensity of the reflected light change the information gathered and must be accounted for in calibration. Turning the measuring probe 30 degrees or more at 5 mm distance reduced the effect of high intensity specular reflection. Temperature displayed differences in the spectra, cold samples giving less response than warm samples although no clear correlation was found. Multivariate analysis of the contact measurement samples gave most accurate result after multiple signal correction preprocessing. Distance measurements on fiber rendered models with high RMSEC values and gave no reasonable base for prediction.

  • 91.
    Dahlquist, Erik
    et al.
    Mälardalen University (MDH), Sweden.
    Naqvi, Muhammad
    Mälardalen University (MDH), Sweden.
    Thorin, Eva
    Mälardalen University (MDH), Sweden.
    Kyprianidis, Jinyue Yan: Konstantinos
    Mälardalen University (MDH), Sweden.
    Hartwell, Philip
    BioRegional MiniMills (UK) Ltd.
    Modeling of Black Liquor Gasification2016Ingår i: Proceedings of 2016 9th EUROSIM Congress on Modelling and Simulation / [ed] Esko Juuso, Erik Dahlquist, Kauko Leiviskä, 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    The energy situation in both process industries andpower plants is changing. It is becoming interesting toperform system analysis on how to integrate gasificationinto chemical recovery systems in the pulp & paperindustry and into the CHP systems in power plantapplications to complement with production ofchemicals aside of heat and power. The potentialchemicals are methane, hydrogen, and methanol. It isalso interesting to estimate the potential to introducecombined cycles with gas turbines and steam turbinesusing both black liquors and other type of biomass likepellets, wood chips etc. To perform such type ofanalysis, it is vital to have relevant input data on whatgas composition we can expect from running differenttypes of feedstock. In this paper, we focus on blackliquors as feedstock for integrated gasification systems.The experimental results are correlated into partial leastsquares models to predict major composition of thesynthesis gas produced under different conditions.These quality prediction models are then combined withphysical models using Modelica for the investigation ofdynamic energy and material balances for completeplants. The data can also be used as input to analysisusing e.g. ASPEN plus and similar system analysistools

  • 92.
    Dahlquist, Erik
    et al.
    Malardalen Univ MDH, Sweden..
    Naqvi, Muhammad
    Malardalen Univ MDH, Sweden..
    Thorin, Eva
    Malardalen Univ MDH, Sweden..
    Yan, Jinyue
    Malardalen Univ MDH, Sweden.;Royal Inst Technol KTH, Sweden..
    Kyprianidis, Konstantinos
    Malardalen Univ MDH, Sweden..
    Comparison of gas quality from black liquor and wood pellet gasification using Modelica simulation and pilot plant results2017Ingår i: 8TH INTERNATIONAL CONFERENCE ON APPLIED ENERGY (ICAE2016) / [ed] Yan, J Sun, F Chou, SK Desideri, U Li, H Campana, P Xiong, R, Amsterdam: Elsevier, 2017, s. 992-998Konferensbidrag (Refereegranskat)
    Abstract [en]

    There is a potential to integrate biomass gasification with pulp & paper and CHP plants in order to complement the existing systems with production of chemicals, such as methane, hydrogen, and methanol etc. To perform system analysis of such integration, it is important to gain knowledge of relevant input data on expected synthesis gas composition by gasifying different types of feed stock. In this paper, the synthesis gas quality from wood pellets gasification (WPG) has been compared with black liquor gasification (BLG) through modeling and experimental results at pilot scale. In addition, the study develops regression models like Partial Least Squares (PLS) made from the experimental data. The regression models are then combined with dynamic models developed in Modelica for the investigation of dynamic energy and material balances for integrated plants. The data presented in this study could be used as input to relevant analysis using e.g. ASPEN plus and similar system analysis tools.

  • 93.
    Dahlquist, Erik
    et al.
    Mälardalens högskola.
    Naqvi, Muhammad
    Mälardalens högskola.
    Thorin, Eva
    Mälardalens högskola.
    Yan, Jinyue
    Mälardalens högskola; KTH.
    Kyprianidis, Konstantinos
    Mälardalens högskola.
    Hartwell, Philip
    BioReg MiniMills Ltd, England.
    Experimental and numerical investigation of pellet and black liquor gasification for polygeneration plant2017Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 204, s. 1055-1064Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is vital to perform system analysis on integrated biomass gasification in chemical recovery systems in pulp and paper and heat and power plants for polygeneration applications. The proposed integration complements existing pulp and paper and heat and power production systems with production of chemicals such as methane and hydrogen. The potential to introduce gasification-based combined cycles comprising gas turbines and steam turbines to utilize black liquors and wood pellets also merits investigation. To perform such analysis, it is important to first build knowledge on expected synthesis gas composition by gasifying at smaller scale different types of feed stock. In the present paper, the synthesis gas quality from wood pellets gasification has been compared with black liquor gasification by means of numerical simulation as well as through pilot-scale experimental investigations. The experimental results have been correlated into partial least squares models to predict the composition of the synthesis gas produced under different operating conditions. The gas quality prediction models are combined with physical models using a generic open-source modelling language for investigating the dynamic performance of large-scale integrated polygeneration plants. The analysis is further complemented by considering potential gas separation using modern membrane technology for upgrading the synthesis gas with respect to hydrogen content. The experimental data and statistical models presented in this study form an important literature source for future use by the gasification and polygeneration research community on further integrated system analysis. (C) 2017 Elsevier Ltd. All rights reserved.

  • 94.
    Dahlquist, Erik
    et al.
    Mälardalen University, .
    Naqvi, Muhammad
    Mälardalen University, KTH.
    Thorin, Eva
    Mälardalen University, .
    Yan, Jinyue
    Mälardalen University, KTH.
    Kyprianidis, Konstantinos
    Mälardalen University, .
    Hartwell, Philip
    BioRegional MiniMills Ltd., United Kingdom..
    Modeling of Wood Gasification in an Atmospheric CFB Plant2016Ingår i: Proceedings of 2016 9th EUROSIM Congress on Modelling and Simulation / [ed] Esko Juuso, Erik Dahlquist, Kauko Leiviskä, Linköping University Electronic Press , 2016, s. 872-877Konferensbidrag (Refereegranskat)
    Abstract [en]

    The energy situation in both process industries andpower plants is changing and it is of interest toinvestigate new polygeneration solutions combiningproduction of chemicals with the production of powerand heat. Examples of such chemicals are methane,hydrogen, and methanol etc. Integration of gasificationinto chemical recovery systems in the pulp and paperproduction systems and into the combined heat andpower (CHP) systems in power plant applications areamong the possible polygeneration systems. It is alsointeresting to look at the potential to introduce combinedcycles with gas turbines and steam turbines as acomplement. To perform such analysis, it is importantto have relevant input data on what gas composition wecan expect from running different type of feed stock. Inthis paper, we focus on the wood pellets. Experimentalresults are correlated into partial least squares models topredict major composition of the synthesis gas producedunder different operating conditions. The qualityprediction models then are combined with physicalmodels using Modelica for investigation of dynamicenergy and material balances for large plants. The datacan also be used as input to analysis using e.g. ASPENplus and similar system analysis tools.

  • 95.
    Danielsson, Fredrik
    Karlstads universitet, Institutionen för kemi.
    Optimering av blekeriet i CTMP-linjen vid Rottneros Bruk2006Självständigt arbete på grundnivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats
    Abstract [en]

    At Rottneros pulp mill mechanical pulp is bleached with hydrogen peroxide. The changes of bleaching chemicals that are used for different grades are taken from bleaching tables; however these tables are old and need to be updated. The purpose of this thesis was to be the basis of new documentation.

    In this thesis three pulps where studied with the aim to find the optimal bleaching chemical changes (total NaOH/VP-quote) for each pulp. The pulps were taken from the filter before the bleaching tower and the pulps were bleached in the lab. The most important pulp property in this study was the brightness and how that was influenced by the chemical dosages. A fiberline inspection was also done to examine the brightness gain during the process. Finally a study was carried out to examine how freeness affected the brightness for low- and high freeness pulps.

    The studies showed that reduced chemical consumption was possible to achieve for all pulps studied. For pulp CA 683 a total NaOH/VP-ratio of 0,8 was suggested, while the ratio were 1,1 for CA 970 and 0,7 for CS 770.

    Lower freeness increased the brightening of the pulp at the same chemical consumption.

  • 96.
    Danish, Muhammad
    et al.
    East China Univ Sci & Technol, Peoples R China..
    Gu, Xiaogang
    East China Univ Sci & Technol, Peoples R China..
    Lu, Shuguang
    East China Univ Sci & Technol, Peoples R China..
    Ahmad, Ayyaz
    Muhammad Nawaz Sharif Univ Engn & Technol, Pakistan..
    Naqvi, Muhammad
    Malardalen Univ, Sweden..
    Farooq, Usman
    East China Univ Sci & Technol, Peoples R China..
    Zhang, Xiang
    East China Univ Sci & Technol, Peoples R China..
    Fu, Xiaori
    East China Univ Sci & Technol, Peoples R China..
    Miao, Zhouwei
    East China Univ Sci & Technol, Peoples R China..
    Xue, Yunfei
    East China Univ Sci & Technol,Peoples R China..
    Efficient transformation of trichloroethylene activated through sodium percarbonate using heterogeneous zeolite supported nano zero valent iron-copper bimetallic composite2017Ingår i: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 308, s. 396-407Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Zeolite supported nano zero valent iron copper bimetallic composite (Z-nZVFe-Cu) was synthesized using an ion exchange method. The morphology and physico-chemical properties of the Z-nZVFe-Cu composite were determined using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Brunauer Emmett Teller (BET), energy dispersive X-ray spectra (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometer (XRD). The results showed that iron and copper nano particles were well dispersed on the zeolite sheet. The degradation efficiency of trichloroethylene (TCE) achieved was more than 95% using Z-nZVFe-Cu as a heterogeneous Fenton like catalyst. An efficient removal of total organic carbon (TOC) was promoted as compared to zeolite supported iron nano composite (Z-nZVFe) and unsupported nano iron (nZVFe). Electron spin resonance (ESR) detection confirmed the intensity of hydroxyl radicals (OH.) in the system. While benzoic acid (BA), a probe indicator for the quantification of OH., demonstrated the higher intensity of hydroxyl radicals in Z-nZVFe-Cu as compared to Z-nZVFe and nZVFe. The less iron and copper leaching of from Z-nZVFe-Cu presented its higher stability and better catalytic activity, displaying its potential long term applications for TCE degradation in groundwater. (C) 2016 Elsevier B.V. All rights reserved.

  • 97.
    Danish, Muhammad
    et al.
    East China Univ Sci & Technol, Peoples R China..
    Gu, Xiaogang
    East China Univ Sci & Technol, Peoples R China..
    Lu, Shuguang
    East China Univ Sci & Technol, Peoples R China..
    Brusseau, Mark L.
    Univ Arizona, USA.
    Ahmad, Ayyaz
    Muhammad Nawaz Sharif Univ Engn & Technol, Pakistan..
    Naqvi, Muhammad
    Malardalen Univ, Sweden..
    Farooq, Usman
    East China Univ Sci & Technol, State Environm Protect Key Lab Environm Risk Asse, Shanghai 200237, Peoples R China..
    Zaman, Waqas Qamar
    East China Univ Sci & Technol, Peoples R China..
    Fu, Xiaori
    East China Univ Sci & Technol, Peoples R China..
    Miao, Zhouwei
    East China Univ Sci & Technol, Peoples R China..
    An efficient catalytic degradation of trichloroethene in a percarbonate system catalyzed by ultra-fine heterogeneous zeolite supported zero valent iron-nickel bimetallic composite2017Ingår i: Applied Catalysis A: General, ISSN 0926-860X, E-ISSN 1873-3875, Vol. 531, s. 177-186Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Zeolite supported nano iron-nickel bimetallic composite (Z-nZVI-Ni) was prepared using a liquid-phase reduction process. The corresponding surface morphologies and physico-chemical properties of the Z-nZVI-Ni composite were determined using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy dispersive X-ray spectra (EDS), Brunauer Emmett Teller (BET) adsorption, wide angle X-ray diffractometry (WA-XRD), and Fourier transform infrared spectroscopy (FTIR). The results indicated high dispersion of iron and nickel nano particles on the zeolite sheet with an enhanced surface area. Complete destruction of trichloroethene (TCE) and efficient removal of total organic carbon (TOC) were observed by using Z-nZVI-Ni as a heterogeneous catalyst for a Fenton-like oxidation process employing sodium percarbonate (SPC) as an oxidant. The electron spin resonance (ESR) of Z-nZVI-Ni verified the generation and intensity of hydroxyl radicals (OH center dot). The quantification of OH center dot elucidated by using p-chlorobenzoic acid, a probe indicator, confirmed the higher intensity of OH center dot. The transformation products were identified using GC-MS. The slow iron and nickel leaching offered higher stability and better catalytic activity of Z-nZVI-Ni, demonstrating its prospective long term applications in groundwater for TCE degradation. (C) 2016 Elsevier B.V. All rights reserved.

  • 98.
    Danish, Muhammad
    et al.
    East China Univ Sci & Technol, Peoples R China..
    Gu, Xiaogang
    East China Univ Sci & Technol, Peoples R China..
    Lu, Shuguang
    East China Univ Sci & Technol, Peoples R China..
    Farooq, Usman
    East China Univ Sci & Technol, Peoples R China..
    Ahmad, Ayyaz
    Univ Engn & Technol, Pakistan..
    Naqvi, Muhammad
    Malardalen Univ, Sweden..
    Zhang, Xiang
    East China Univ Sci & Technol, Peoples R China..
    Fu, Xiaori
    East China Univ Sci & Technol, Peoples R China..
    Xue, Yunfei
    East China Univ Sci & Technol, Peoples R China..
    Effect of solution matrix and pH in Z-nZVI-catalyzed percarbonate system on the generation of reactive oxygen species and degradation of 1,1,1-trichloroethane2017Ingår i: Water Science and Technology: Water Supply, ISSN 1606-9749, E-ISSN 1607-0798, Vol. 17, nr 6, s. 1568-1578Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study primarily focuses on evaluating the effects of solution matrix and pH for the generation of reactive oxygen species (ROSs) in a Z-nZVI-catalyzed sodium percarbonate (SPC) system to degrade 1,1,1-trichloroethane (1,1,1-TCA) in the absence and presence of a reducing agent (RA), i.e. hydroxylamine. Degradation of 1,1,1-TCA was 49.5% and 95% in the absence and presence of RA. Probe tests confirmed the generation of major hydroxyl radicals (OH center dot) and minor superoxide species (O-2(-center dot)), and scavenger tests verified the key role of OH center dot and less of O-2(-center dot) radicals. Degradation of 1,1,1-TCA decreased significantly in the presence of Cl- and HCO3-, while NO3- and SO42- had negligible effects in the absence of RA. Addition of RA significantly enhanced 1,1,1-TCA degradation by generating more OH center dot and O-2(-center dot) radicals in the presence of anions. Degradation of 1,1,1-TCA increased in the acidic range (1-5), while an inhibitive trend from neutral to basic (7-9) was observed. In contrast, a significant increase in 1,1,1-TCA degradation was observed with the addition of RA at all pH values (1-9). In conclusion, the anions and pH significantly influenced the generation and intensity of ROSs and 1,1,1-TCA was effectively degraded in the Z-nZVI-catalyzed SPC system in the presence of RA.

  • 99.
    Danish, Muhammad
    et al.
    E China Univ Sci & Technol, State Environm Protect Key Lab Environm Risk Asse, Shanghai 200237, Peoples R China..
    Gu, Xiaogang
    E China Univ Sci & Technol, State Environm Protect Key Lab Environm Risk Asse, Shanghai 200237, Peoples R China..
    Lu, Shuguang
    E China Univ Sci & Technol, State Environm Protect Key Lab Environm Risk Asse, Shanghai 200237, Peoples R China..
    Naqvi, Muhammad
    Mälardalens högskola.
    Degradation of chlorinated organic solvents in aqueous percarbonate system using zeolite supported nano zero valent iron (Z-nZVI) composite2016Ingår i: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 23, nr 13, s. 13298-13307Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Chlorinated organic solvents (COSs) are extensively detected in contaminated soil and groundwater that pose long-term threats to human life and environment. In order to degrade COSs effectively, a novel catalytic composite of natural zeolite-supported nano zero valent iron (Z-nZVI) was synthesized in this study. The performance of Z-nZVI-catalyzed sodium percarbonate (SPC) in a heterogeneous Fenton-like system was investigated for the degradation of COSs such as 1,1,1-trichloroethane (1,1,1-TCA) and trichloroethylene (TCE). The surface characteristics and morphology of the Z-nZVI composite were tested using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Total pore volume, specific surface area, and pore size of the natural zeolite and the Z-nZVI composite were measured using Brunauer-Emmett-Teller (BET) method. SEM and TEM analysis showed significant elimination of aggregation and well dispersion of iron nano particles on the framework of natural zeolite. The BET N-2 measurement analysis indicated that the surface area of the Z-nZVI composite was 72.3 m(2)/g, much larger than that of the natural zeolite (0.61 m(2)/g). For the contaminant analysis, the samples were extracted with n-hexane and analyzed through gas chromatograph. The degradation of 1,1,1-TCA and TCE in the Z-nZVI-catalyzed percarbonate system were 48 and 39 % respectively, while strong augmentation was observed up to 83 and 99 %, respectively, by adding the reducing agent (RA), hydroxyl amine (NH2OH center dot HCl). Probe tests validated the presence of OH center dot and O-2(center dot-) which were responsible for 1,1,1-TCA and TCE degradation, whereas both free radicals were strengthened with the addition of RA. In conclusion, the Z-nZVI/SPC oxidation with reducing agent shows potential technique for degradation of groundwater contaminated by 1,1,1-TCA and TCE.

  • 100.
    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..
    Xu, Minhui
    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..
    Naqvi, Muhammad
    Mälardalens högskola.
    Nasir, Muhammad
    COMSATS Inst Informat Technol, IRCBM, Lahore, Pakistan..
    Role of reactive oxygen species and effect of solution matrix in trichloroethylene degradation from aqueous solution by zeolite-supported nano iron as percarbonate activator2016Ingår i: Research on chemical intermediates (Print), ISSN 0922-6168, E-ISSN 1568-5675, Vol. 42, nr 9, s. 6959-6973Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The role of reactive oxygen species (ROSs) and effect of solution matrix have been investigated for the degradation of trichloroethylene (TCE). Zeolite-supported nano iron (Z-nZVI) was synthesized as an activator to catalyze sodium percarbonate (SPC) with or without hydroxylamine, i.e. as reducing agent (RA). The probe tests confirmed the generation of OH center dot and O-2(-center dot) in the Z-nZVI activated SPC system in absence of the RA, while the presence of RA significantly increased the generation of OH center dot and O-2(-center dot) radicals. Scavenger tests demonstrated that OH center dot was the main ROS responsible for TCE degradation, whereas O-2(-center dot) also participated in TCE degradation. From the solution matrix perspective, the experimental results confirmed significant scavenging effects of Cl- (1.0, 10.0, and 100 mmol L-1) and HCO3- (1.0 and 10.0 mmol L-1), whereas the scavenging effects were fairly impeded at 100 mmol L-1 concentration of HCO3-. On the other hand, a considerable decline in scavenging effect was observed in the presence of RA in tested Cl and HCO3- concentration ranges. In addition, negligible scavenging effects of NO3- and SO42- anions were found in all tested concentrations. The effect of initial solution pH on catalytic activity indicated a significant increase in the TCE degradation in the presence of RA even at higher pH value of 9. The results indicated that the Z-nZVI activated SPC system in presence of RA can effectively degrade chlorinated organic solvents, but it is important to consider the intensive existence of anions in groundwater.

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