| 1. |
- Berg, Jan-Erik, 1957-, et al.
(författare)
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Refining gentleness - a key to bulky CTMP
- 2022
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Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 37:2, s. 349-355
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Tidskriftsartikel (refereegranskat)abstract
- Chemithermomechanical pulp (CTMP) is often used in middle layers of multiply paperboards due to its high bulk at specified strength. Such a CTMP should consist of well-separated undamaged fibres with sufficient bonding capacity. The basic objective of this work is to examine the effect of refining on bulk, taking into account conditions such as temperature, sulphonation, refining gap and refiner size. First stage CTMP made from Norway spruce (Picea abies) were produced in pilot and mill scale trials. Two new parameters, Equivalent temperature related to softness and Refining gentleness are introduced that take into account refining conditions as actual temperature, softening temperature, bound sulphonate content, refining gap and refiner diameter. The results show that bulk increases linearly with refining gentleness.
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| 2. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Alimohammadzadeh, Rana, et al.
(författare)
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Improving the mechanical properties of CTMP fibers by combining synergistic organocatalytic/polyelectrolyte complex surface engineering with sulfite pretreatment
- 2022
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Ingår i: Proceedings of the International Mechanical Pulping Conference. ; , s. 149-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Fabrication of paper-based packaging materials is increasing and the challenge is developing a sustainable process to manufacture the materials that can compete with plastics. Employing stronger fiber in production of fiber-based materials improves the efficiency of fabrication process by using a reduced amount of biomass. Cationic starch is a well-known polysaccharide that has been introduced to paper and paperboard fibers to improve the mechanical properties of lignocellulosic fibers. The polyelectrolyte (PE) multilayer method has been popularized as a new and interesting technique to enhance the adsorption of cationic starch on the fiber for improving the strength properties of chemi-thermomechanical pulp (CTMP), chemical and kraft pulps. We have shown in our previous work that the synergistic combination of organocatalysis and PE complexes improved the mechanical properties of CTMP and TMP. In this work, we chose to expand this concept by integrating it with low-dose sulfite pretreatment of wood chips in preparation of CTMP. Thus, CTMP produced by initial sulfite pre-treatment was next surface engineered by synergistic combination of organocatalysis and PE complexes using organic acids as catalysts. The CTMP pulps, which contains 0.1-0.24 wt.% sulfur, produced by our novel pulp-engineering strategy shows a dramatic strength increase (Z- strength: up to 100 %) as compared to no surface engineering. While only sulfite pre-treatment and PE-complex surface engineering were able to improve the strength properties, it was only when the organic catalysts was present that the highest strength improvements were reached. Thus, a clear synergistic effect of the catalyst was observed.
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| 4. |
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| 5. |
- Augustsson, Nils-Petter, 1972-, et al.
(författare)
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The character of a VR -visualization
- 2003
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Ingår i: Proceedings of the 26th International Systems Research in Scandinavia (IRIS)Conference.
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Konferensbidrag (refereegranskat)abstract
- When we humans are dealing with complex things in our daily lives, for example an artifact, we tend to ascribe different characters to it. This is our way of getting a quick overview of the artifact and makes it understandable to us. The ascribing of character is not based on thorough examination of the object at hand though, but rather on a certain thing, i.e. a characteristic that catches our attention. This characteristic gives us a certain feeling about the artifact and makes it possible for us to make a judgment about it, even if it is a snap one. With this as a starting point we try to identify the different characteristics, which constitute the overall character, i.e. realism. In many visualisations with this objective, realism is juxtaposed with copying static structures, i.e. buildings and streets. This is also a strong contributor to the realism character in the Botnia-track visualisation. In our opinion this is not enough to get a realistic character. We have identified a few other prominent characteristics that also are important contributors to the realism character, for example landmarks, sound, moving objects and narrator voice. Our main conclusion is that if a realistic character is desirable, more than visualisation of static structures is necessary. We found at least five additional characteristics that influence people’s perception of a virtualisation; landmarks, sound, moving objects and narrator voice. In our opinion, all of these are important for a realistic character to emerge and something that designers have to take in to consideration to reach the intended goal.
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| 6. |
- Berntsson, Thore, 1947, et al.
(författare)
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Towards Sustainabel Oil Refinery - Pre-study for larger co-operation project
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this report, the Chalmers EnergiCentrum (CEC) presents the results of a pre-study commissioned by Preem relating to the effective production of future vehicle fuels.This pre-study was made up of three studies focusing on energy streamlining, the utilisation of waste heat and carbon-dioxide separation and biorefinement relating to the gasification and hydration of vegetable oils. One of the common starting points for these studies was the current situation at the Preem refineries in Göteborg and Lysekil from where the measurement data were obtained and analysed. The report summarises the knowledge situation based on current research in the individual technical fields. The results present some interesting future opportunities for developing the sustainable production of future vehicle fuels. The sections vary, as the areas that have been examined differ and the sections have been written by different people. The reports ends with some joint conclusions and a number of questions which could be included and answered in a more extensive future main study, as part of a developed research partnership between Preem and the Chalmers University of Technology. The preliminary results of this work were analysed with the client at workshops on 1 October and 29 November 2007. The report is written in English combined with an extensive summary in Swedish including a proposal on a future main study. The study was conducted by the Chalmers EnergiCentrum (CEC), in collaboration with a number of researchers in the CEC’s network. They included Thore Berntsson, Jessica Algehed, Erik Hektor and Lennart Persson Elmeroth, all from Heat and Power Technology, Börje Gevert, Chemical and Biological Engineering, Tobias Richards, Forest Products and Chemical Engineering, Filip Johnsson and Anders Lyngfelt, Energy Technology, and Per-Åke Franck and Anders Åsblad, CIT Industriell Energianalys AB. The client, Preem, was represented by Bengt Ahlén, Sören Eriksson, Johan Jervehed, Bertil Karlsson, Gunnar Olsson, Ulf Kuylenstierna, Stefan Nyström, Martin Sjöberg and Thomas Ögren. Tobias Richards was responsible for compiling the report and Bertil Pettersson was the project manager.
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| 9. |
- Carlsson, Per-Anders, 1972, et al.
(författare)
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Periodic control for improved low-temperature catalytic activity
- 2001
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Ingår i: Topics in Catalysis. - 1572-9028 .- 1022-5528. ; 16-17:1-4, s. 343-347
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Tidskriftsartikel (refereegranskat)abstract
- The influence of transient changes in the gas composition on the low-temperature activity of a commercial three-way catalyst and a Pt/Al2O3 model catalyst has been studied. By introducing well-controlled periodic O2 pulses to simple gas mixtures of CO or C3H6 (in N2), a substantial improvement of the low temperature oxidation activity was observed for both catalysts. The reason for low activity at low temperatures is normally attributed to self-poisoning by CO or hydrocarbons. The improved catalytic performance observed here is suggested to origin from the transients causing a surface reactant composition that is favourable for the reaction rate.
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| 10. |
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