| 1. |
- Forsberg, Håkan, et al.
(författare)
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Methods for Enhancement of a Master of Engineering Programme
- 2019
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Konferensbidrag (refereegranskat)abstract
- This paper describes methods we used to improve our Master of Engineering programme in Dependable Aerospace Systems together with the industry. The target audience is mainly programme coordinators/managers who are in the process to develop their programmes for future demands. The two main questions we address are: Q1 – How do we ensure a good progression within a programme to ensure the industry’s current and future needs in engineering skills? and Q2 – How do we ensure students become acquainted with research during their studies? The results indicate that our suggested method to analyse programme progression through subject abilities supports developer of engineering programmes and that our approach to undergraduate research opportunities is a way forward to introduce students to research early.
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| 2. |
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| 3. |
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| 4. |
- Andres, Britta, 1986-, et al.
(författare)
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Electrode Mass Balancing as an Inexpensive and Simple Method to Increase the Capacitance of Electric Double-Layer Capacitors
- 2016
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:9, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Symmetric electric double-layer capacitors (EDLCs) have equal masses of the same active material in both electrodes. However, having equal electrode masses may prevent the EDLC to have the largest possible specific capacitance if the sizes of the hydrated anions and cations in the electrolyte differ because the electrodes and the electrolyte may not be completely utilized. Here we demonstrate how this issue can be resolved by mass balancing. If the electrode masses are adjusted according to the size of the ions, one can easily increase an EDLC's specific capacitance. To that end, we performed galvanostatic cycling to measure the capacitances of symmetric EDLCs with different electrode mass ratios using four aqueous electrolytes-Na2SO4, H2SO4, NaOH, and KOH (all with a concentration of 1 M)-and compared these to the theoretical optimal electrode mass ratio that we calculated using the sizes of the hydrated ions. Both the theoretical and experimental values revealed lower-than-1 optimal electrode ratios for all electrolytes except KOH. The largest increase in capacitance was obtained for EDLCs with NaOH as electrolyte. Specifically, we demonstrate an increase of the specific capacitance by 8.6% by adjusting the electrode mass ratio from 1 to 0.86. Our findings demonstrate that electrode mass balancing is a simple and inexpensive method to increase the capacitance of EDLCs. Furthermore, our results imply that one can reduce the amount of unused material in EDLCs and thus decrease their weight, volume and cost.
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| 6. |
- Balliu, Enkeleda, et al.
(författare)
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Laser-assisted reduction of graphene oxide for paper based large area flexible electronics
- 2016
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE - International Society for Optical Engineering. - 9781628419719
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Konferensbidrag (refereegranskat)abstract
- In this work we present a promising method for fabrication of conductive tracks on paper based substrates by laser assisted reduction of Graphene Oxide (GO). Printed electronics on paper based substrates is be coming more popular due to lower cost and recyclability. Fabrication of conductive tracks is of great importance where metal, carbon and polymer inks are commonly used. An emerging option is reduced graphene oxide (r-GO), which can be a good conductor. Here we have evaluated reduction of GO by using a 532 nm laser source, showing promising results with a decrease of sheet resistance from >100 M Ω/Sqr for unreduced GO down to 126 Ω/Sqr. without any observable damage to the paper substrates.
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| 7. |
- Balliu, Enkeleda, PhD student, et al.
(författare)
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Laser processing of graphene oxide on different coated paper substrates
- 2016
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Ingår i: 14th TAPPI Advanced Coating Symposium 2016. - : TAPPI Press. - 9781510877658 ; , s. 97-101
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Konferensbidrag (refereegranskat)abstract
- Development of printed electronics is increasing each year, where many electrical components such as transistors and sensors are now printable. The most commonly used substrate have been plastics, but there is an increasing interest in using paper as substrate. The paper industry is a very large and mature industry with large production capacity and well developed processes. It is therefore of interest to investigate how it would be possible to combine printed electronics and paper based products. This can for example be to print sensors on packages, to use large scale roll-to-roll production for solar cells. To be able to achieve such goals it is of importance to develop methods of applying electrically active materials in the large, high speed roll-to-roll processes used in the paper industry. In this article we discuss coating of graphene oxide (GO) on large areas after which it is selectively reduced into electrically conductive reduced graphene oxide (rGO) by laser processing. Graphene oxide is an inexpensive, carbon based material very suitable to be deposited as a coating, and the selective activation of makes it possible to fabricate conductive patterns at high speeds. We have evaluated several different paper substrates on which GO was coated. The reduction was performed using an 532 nm laser source and the results are promising, showing that it is possible to fabricate selectively conductive patterns on paper substrates by coating and reduction of GO.
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| 8. |
- Blomquist, Nicklas, 1987-, et al.
(författare)
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Large-Scale Production of Nanographite by Tube-Shear Exfoliation in Water
- 2016
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Ingår i: PLOS ONE. - : Nicklas Blomquist. - 1932-6203. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- The number of applications based on graphene, few-layer graphene, and nanographite is rapidly increasing. A large-scale process for production of these materials is critically needed to achieve cost-effective commercial products. Here, we present a novel process to mechanically exfoliate industrial quantities of nanographite from graphite in an aqueous environment with low energy consumption and at controlled shear conditions. This process, based on hydrodynamic tube shearing, produced nanometer-thick and micrometer-wide flakes of nanographite with a production rate exceeding 500 gh-1 with an energy consumption about 10 Whg-1. In addition, to facilitate large-area coating, we show that the nanographite can be mixed with nanofibrillated cellulose in the process to form highly conductive, robust and environmentally friendly composites. This composite has a sheet resistance below 1.75 Ω/sq and an electrical resistivity of 1.39×10-4 Ωm and may find use in several applications, from supercapacitors and batteries to printed electronics and solar cells. A batch of 100 liter was processed in less than 4 hours. The design of the process allow scaling to even larger volumes and the low energy consumption indicates a low-cost process.
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| 9. |
- Blomquist, Nicklas, 1987-, et al.
(författare)
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Metal-free supercapacitor with aqueous electrolyte and low-cost carbon materials
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Electric double-layer capacitors (EDLCs) or supercapacitors (SCs) are fast energy storage devices with high pulse efficiency and superior cyclability, which makes them useful in various applications including electronics, vehicles and grids. Aqueous SCs are considered to be more environmentally friendly than those based on organic electrolytes. Because of the corrosive nature of the aqueous environment, however, expensive electrochemically stable materials are needed for the current collectors and electrodes in aqueous SCs. This results in high costs for a given energy-storage capacity. To address this, we developed a novel low-cost aqueous SC using graphite foil as the current collector and a mix of graphene, nanographite, simple water-purification carbons and nanocellulose as electrodes. The electrodes were coated directly onto the graphite foil by using casting frames and the SCs were assembled in a pouch cell design. With this approach, we achieved a material cost reduction of greater than 90% while maintaining approximately one-half of the specific capacitance of a commercial unit, thus demonstrating that the proposed SC can be an environmentally friendly, low-cost alternative to conventional SCs.
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| 10. |
- Dahlstedt, Magnus, et al.
(författare)
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Systemet med fritt skolval måste bytas ut
- 2018
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Ingår i: Svenska Dagbladet.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Ökad segregation och deprofessionalisering av läraryrket är några av effekterna av det fria skolvalet. Nu krävs en grundlig utredning med siktet inställt på att hitta alternativ till nuvarande marknadssystem, skriver ett flertal forskare.
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