| 1. |
- Holmqvist, Claes
(författare)
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Cellulose foams: Sustainable solutions to replace fossil-based plastic foams
- 2024
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Apple and RISE Research Institutes of Sweden are committed to contribute to solving the ongoing plastic pollution crisis. In a joint undertaking, we have created an innovative, low-density, resilient, cellulose foam, based on responsibly sourced wood pulp that can be sustainably produced and recycled in the paper packaging recycling stream. Its structure and mechanical properties suggest it could replace fossil-based materials, such as polymeric foams, commonly used in packaging, insulation, and light weight composites. To accelerate progress, and shorten time to market, we are now inviting partners to build on the work we have done and develop the material toward different applications.
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| 2. |
- Söderman Lago, Lina, 1979-, et al.
(författare)
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Att synliggöra ett fritidspedagogiskt förhållningssätt
- 2022
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Ingår i: Venue. - Linköping : Utbildningsvetenskap, Linköpings universitet. - 2001-788X. ; :21
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Vad är kärnan i fritidshemmets undervisning, hur kan fritidspedagogiska förhållningssätt synliggöras och utvecklas och vad kräver det för lärarposition? Sådana frågor har varit utgångspunkt för det ULF-projekt som presenteras i denna artikel.
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| 3. |
- Krochak, Paul, et al.
(författare)
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The effect of contact time between CPAM and colloidal silica on the flocculation behavior in the approach flow
- 2021
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Ingår i: TAPPI Journal. - : TAPPI Press. - 0734-1415. ; 20:1, s. 39-47
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Tidskriftsartikel (refereegranskat)abstract
- Multicomponent wet-end systems have become increasingly common in papermaking, with the objective of improving the retention-formation-dewatering relationship. It is quite common to use at least a cationic polymer, often in combination with an anionic microparticle. In some cases, a fixative is also used. However, there is still debate on the optimal implementation of these systems. In particular, optimizing the contact time of the cationic polymer prior to addition of the anionic microparticle is still poorly understood. In this work, we investigate the effect of the contact time of a cationic polyacrylamide (CPAM) prior to addition of colloidal silica on the flocculation response in a flowing fiber suspension. The effect of using a fixative is also investigated. Focused beam reflectance measurements (FBRM) are combined with zeta-potential measurements for optimizing the addition levels of a two- and three-component system, as well as for elucidating the effect of contact time on CPAM performance. Trials are then performed on a pilot scale flow loop, where the time between addition of these two components is varied and the resulting flocculation response is characterized using high-speed filming and image anal. techniques. It is shown that the efficacy of CPAM can be improved through use of a fixative and that a longer CPAM contact time may be beneficial in terms of immediate flocculation; however, hydrodynamic shear tends to dominate the flocculation response regardless of contact time due to floc rupture.
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| 4. |
- De San Pio, Ignacio, et al.
(författare)
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A novel predictive method for filler coflocculation with cellulose microfibrils
- 2020
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Ingår i: TAPPI Journal. - : TAPPI Press. - 0734-1415. ; 18:11, s. 653-664
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Tidskriftsartikel (refereegranskat)abstract
- Different strategies aimed at reducing the negative impact of fillers on paper strength have been the objective of many studies during the past few decades. Some new strategies have even been patented or commercialized, yet a complete study on the behavior of the filler flocs and their effect on retention, drainage, and formation has not been found in literature. This type of research on fillers is often limited by difficulties in simulating high levels of shear at laboratory scale similar to those at mill scale. To address this challenge, a combination of techniques was used to compare preflocculation (i.e., filler is flocculated before addition to the pulp) with coflocculation strategies (i.e., filler is mixed with a binder and flocculated before addition to the pulp). The effect on filler and fiber flocs size was studied in a pilot flow loop using focal beam reflectance measurement (FBRM) and image analysis. Flocs obtained with cationic polyacrylamide (CPAM) and bentonite were shown to have similar shear resistance with both strategies, whereas cationic starch (CS) was clearly more advantageous when coflocculation strategy was used. The effect of flocculation strategy on drainage rate, STFI formation, ash retention, and standard strength properties was measured. Coflocculation of filler with CPAM plus bentonite or CS showed promising results and produced sheets with high strength but had a negative impact on wire dewatering, opening a door for further optimization.
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| 5. |
- De San Pio, Ignacio, et al.
(författare)
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Filler co-flocculation with MFC : Novel predictive method
- 2019
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Ingår i: PaperCon 2019. - : TAPPI Press.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Research has been undertaken in which a combination of different techniques was utilised to compare pre-flocculation (flocculant added to the filler prior to its addition to the pulp) with pre-mixing strategies, also called co-flocculation (chemicals added to a mixture of cellulose microfibrils (CMF) and filler. The pulp used was a mixture of 80% hardwood kraft pulp and 20% softwood kraft pulp. The filler was ground calcium carbonate (GCC), while the chemicals used included cationic polyacrylamide (CPAM), silica, bentonite, anionic PAM (APAM), cationic starch and CMF. Using the focused beam reflectance method (FBRM) enabled an in-depth and quick study of the filler floc behaviour at different dosages and mixing conditions, demonstrating that it was a very good tool as a pre-screening for different treatment alternatives. Clear differences in behaviour between different pre-flocculation and pre-mixing strategies were observed. For the pre-mixing strategy, the most promising results were achieved with CPAM plus bentonite and cationic starch systems. Although dewatering was negatively affected with pre-mixing, the mechanical properties were clearly improved. Flocs obtained with PCAM/bentonite had a similar resistance with both strategies, while cationic starch was clearly more advantageous when using the pre-mixing strategy.
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| 6. |
- Ankerfors, Caroline, et al.
(författare)
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Final Report for the Source-Efficient Paper and Board Making Research Programme Area
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This is the final report for the Innventia/RISE Bioeconomy research programme area “Source-Efficient Paper and Board Making”, which was executed 2015-2017.The overall aim of the Source Efficient Paper and Board Making was to improve the resource efficiency in paper and board production. This was achieved by combining paper chemistry, paper physics and process technology. A particular goal was to reduce raw material consumption through the use of stronger materials or creation of bulk, which are needed to maintain bending stiffness and mechanical properties if the grammage is reduced. The work in the project has been carried out in laboratory scale and in pilot scale using the FEX pilot paper machine and the dynamic flow loop.
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| 7. |
- Hansen, Peter H F, et al.
(författare)
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Monitoring cross-thickness distributions of fines and CMF by dyeing and optical measurement
- 2018
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Ingår i: PaperCon 2018. - : TAPPI. - 9781595102683
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Konferensbidrag (refereegranskat)abstract
- A methodology has been verified where the ZD-distribution of a component of the furnish (fines or CMF) can bemonitored. The component to be monitored was dyed using a direct azo-dye before addition to the furnish. Theproduced sheets were sectioned in cross-thickness direction by sequential heat-seal lamination and splitting, usingplastic pouches. The amount of dyed material in a split was monitored using thea* and L* parameters of the CIELabcolor space and the opacity, all measured simultaneously with a spectrophotometer. The value on the green-redaxis,a*, the lightness, L, and the opacity were combined into a new parameter, -a*L/opac. Two mechanisms forfines retention was observed by laboratory studies, mechanical retention by filtering process in the formed fiber weband chemical retention by agglomeration to the fibers.The methodology has recently been applied for monitoring cross-thickness distributions of either CMF or fines inpaper produced in pilot scale trials. For example, it was demonstrated, that the machine settings affected themechanisms for retention of fines in the fiber web during sheet forming and dewatering, with different distributionsof fines in the cross-thickness direction as result.
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| 8. |
- Johansson, Klas
(författare)
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Elfiskeundersökningar inom kalkningsverksamheten 2007
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten är en sammanställning av elfiskeundersökningar genomförda inom ramen för kalkverksamheten med syftet att följa upp kalkningsåtgärder och biologisk återställning. Totalt redovisas elfiskeresultat från 76 olika elfiskade lokaler. 65 av dessa ligger i kalkpåverkade vattendrag och resterande 11 är belägna i kalkopåverkade referensvattendrag. Resultatet visar på att det förekommer öringreproduktion i samtliga målområden för kalkningen där öringen är målart. Reproduktionen är sammantaget dessutom mycket god under 2007 vilket avspeglar sig i höga tätheter på flera lokaler. Vid elfiskena har det även kunnat påvisas att det förekommer en viss naturlig reproduktion av lax i ett par kalkade vattendrag. Samtliga genomförda elfisken 2007 har även statusbedömts utifrån de nya bedömningsgrunderna (Naturvårdsverket 2007). Resultatet från detta antyder att påverkan (t ex försurning) var liten på lokalerna under året. 86 % av elfiskelokalerna uppnådde god eller hög status och endast 9 % klassificerades som dålig till måttlig status. Tittar man på statusbedömningen några år tillbaka på de lokaler som elfiskats under flera år ser man att det förekommer en viss variation i bedömningen på en del lokaler medan andra är mer stabila. Detta medför att man bör ta hänsyn till mer än ett elfiske vid statusbedömning
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| 9. |
- Västberg, Anders, et al.
(författare)
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"Green Radio" in Heterogeneous Wireless Wideband Networks
- 2008
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Konferensbidrag (refereegranskat)abstract
- Heterogeneous networks are an efficient way to support high data rates for non-uniform spatial traffic densities. In this paper we have studied the power consumption of different configurations of heterogeneous wireless networks in an urban environment. The model used is based on simulating the spatial traffic densities with a log-normal distribution, and making Monte-Carlo simulations to estimate the power consumption of different network layouts. We have compared the power consumption of three different network layouts. The power consumption break-even for a macro layer supported by a hotspot layer, compared to a macro cellular layer, is around 25-30 Mbps per square kilometer. At data rates of 100 Mbps per square kilometer, the power consumption of the hotspot supported layout is approximately half of the macro-layer only configuration.
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| 10. |
- Johansson, Klas, et al.
(författare)
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A methodology for estimating cost and performance of heterogeneous wireless access networks
- 2007
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Ingår i: 2007 IEEE 18th International Symposium On Personal, Indoor And Mobile Radio Communications. - 9781424411436 ; , s. 3883-3887
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Konferensbidrag (refereegranskat)abstract
- Wireless access to the Internet will in the future be facilitated by "multi-radio" user terminals that automatically select between available radio access methods. In order to provide affordable wireless data access services an operator could then deploy heterogeneous networks to better match network deployment to traffic demand and fully exploit available infrastructure and radio spectrum. We have previously proposed a methodology for analyzing the total cost and performance of such systems, composed of multiple base station classes and radio access technologies with different cost and technical characteristics, and this work is summarized in this paper. Models and assumptions are outlined and we demonstrate how the methodology can be applied for different combinations of cellular and wireless local area network systems. In conjunction with more specific input data the methodology should be useful for researchers and decision makers as a means to quantify the economics of heterogeneous wireless access networks.
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