| 1. |
- Löfstedt, Håkan, 1963-, et al.
(författare)
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Respiratory and Ocular Symptoms Among Employees at Swedish Indoor Swimming Pools
- 2016
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Ingår i: Journal of Occupational and Environmental Medicine. - : Lippincott Williams & Wilkins. - 1076-2752 .- 1536-5948. ; 58:12, s. 1190-1195
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Tidskriftsartikel (refereegranskat)abstract
- Background: This study investigated trichloramine exposure and prevalence of respiratory and ocular symptoms among Swedish indoor swimming pool workers.Methods: Questionnaires were distributed to pool workers and referents. Lung function and fraction of exhaled nitric oxide (FeNO) were measured before and after work. Exposure to trichloramine and trihalomethanes was measured over work shifts.Results: The mean personal trichloramine exposure was 36g/m(3). Significantly more exposed workers reported ocular and nasal symptoms. There were significant differences between groups in FeNO change following work, with exposed showing increased FeNO, which grew when analyses included only nonsmokers.Conclusions: The findings indicate that indoor swimming pool environments may have irritating effects on mucous membranes. FeNO data also indicate an inflammatory effect on central airways, but the clinical relevance is unclear. Low trichloramine levels found in this study were not associated with health effects.
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| 2. |
- Abdipour, Morteza, et al.
(författare)
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A Design Research Lab—An Integrated Model to Identify Conscious and Unconscious Behavior in the Design Process
- 2016
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Ingår i: Advances in Design for Inclusion. - Cham : Springer. - 9783319419619 - 9783319419626
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Konferensbidrag (refereegranskat)abstract
- To understand how different design solutions affect users, designers traditionally use different evaluation methods that mainly rely on conscious feedback from the users. However, the complexity of human behaviour, where a large part is unconscious, point to a need for an extended tool box addressing the part not accessible to human conscious knowledge. Here, we describe a design research lab where traditional methods are complemented with tools to measure physiological signals influenced by emotional and sympathetic responses. These tools include galvanic skin response (GSR), electrocardiograph (ECG), and electroencephalograph (EEG). Typical sessions with acquired data of conscious and unconscious user reactions are described. The large body of data collected, which also require non-design expertise for interpretation, suggest that a further development towards simplified output data of the unconscious reactions is needed to allow wider use within industrial design work.
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| 3. |
- Alecrim, Viviane, et al.
(författare)
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Exfoliated Layered Materials for Digital Fabrication
- 2015
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Ingår i: NIP & Digital Fabrication Conference. ; , s. 192-194
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Konferensbidrag (refereegranskat)abstract
- We introduced an exfoliation method of MoS2 in a 3% solution of sodium dodecyl surfactant at high concentration (i.e. 2 g/L). The bulk MoS2 was thinned by mechanical exfoliation between sand papers and the resulting powder was used to prepare dispersions by liquid exfoliation through probe sonication. The resulting dispersion consisted of very thin MoS2 nanosheets in surfactant solution with average lateral size around 126 nm. This may be interesting for applications in inkjet printed electronics.
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| 4. |
- Andersson, Henrik, Dr, 1975-, et al.
(författare)
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PEDOT : PSS thermoelectric generators printed on paper substrates
- 2019
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Ingår i: Journal of Low Power Electronics and Applications. - : MDPI AG. - 2079-9268. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- Flexible electronics is a field gathering a growing interest among researchers and companies with widely varying applications, such as organic light emitting diodes, transistors as well as many different sensors. If the circuit should be portable or off-grid, the power sources available are batteries, supercapacitors or some type of power generator. Thermoelectric generators produce electrical energy by the diffusion of charge carriers in response to heat flux caused by a temperature gradient between junctions of dissimilar materials. As wearables, flexible electronics and intelligent packaging applications increase, there is a need for low-cost, recyclable and printable power sources. For such applications, printed thermoelectric generators (TEGs) are an interesting power source, which can also be combined with printable energy storage, such as supercapacitors. Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), or PEDOT:PSS, is a conductive polymer that has gathered interest as a thermoelectric material. Plastic substrates are commonly used for printed electronics, but an interesting and emerging alternative is to use paper. In this article, a printed thermoelectric generator consisting of PEDOT:PSS and silver inks was printed on two common types of paper substrates, which could be used to power electronic circuits on paper.
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| 5. |
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| 6. |
- Andres, Britta, 1986-, et al.
(författare)
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Cellulose binders for electric double-layer capacitor electrodes : The influence of cellulose quality on electrical properties
- 2018
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Ingår i: Materials & design. - : Elsevier BV. - 0264-1275 .- 1873-4197. ; 141, s. 342-349
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Tidskriftsartikel (refereegranskat)abstract
- Cellulose derivatives are widely used as binders and dispersing agents in different applications. Binders composed of cellulose are an environmentally friendly alternative to oil-based polymer binding agents. Previously, we reported the use of cellulose nanofibers (CNFs) as binders in electrodes for electric double-layer capacitors (EDLCs). In addition to good mechanical stability, we demonstrated that CNFs enhanced the electrical performance of the electrodes. However, cellulose fibers can cover a broad range of length scales, and the quality requirements from an electrode perspective have not been thoroughly investigated. To evaluate the influence of fiber quality on electrode properties, we tested seven samples with different fiber dimensions that are based on the same kraft pulp. To capture the length scale from fibers to nanofibrils, we evaluated the performance of the untreated kraft pulp, refined fibers, microfibrillated cellulose (MFC) and CNFs. Electrodes with kraft pulp or refined fibers showed the lowest electrical resistivity. The specific capacitances of all EDLCs were surprisingly similar, but slightly lower for the EDLC with CNFs. The same electrode sample with CNFs also showed a slightly higher equivalent series resistance (ESR), compared to those of the other EDLCs. Graphite dispersions with MFC showed the best dispersion stability.
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| 7. |
- 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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| 8. |
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| 9. |
- Andres, Britta, 1986-
(författare)
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Low-Cost, Environmentally Friendly Electric Double-Layer Capacitors : Concept, Materials and Production
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Today’s society is currently performing an exit from fossilfuel energy sources. The change to sustainable alternativesrequires inexpensive and environmentally friendly energy storagedevices. However, most current devices contain expensive,rare or toxic materials. These materials must be replaced bylow-cost, abundant, nontoxic components.In this thesis, I suggest the production of paper-based electricdouble-layer capacitors (EDLCs) to meet the demand oflow-cost energy storage devices that provide high power density.To fulfill the requirements of sustainable and environmentallyfriendly devices, production of EDLCs that consist of paper,graphite and saltwater is proposed. Paper can be used as aseparator between the electrodes and as a substrate for theelectrodes. Graphite is suited for use as an active material in theelectrodes, and saltwater can be employed as an electrolyte.Westudied and developed different methods for the productionof nanographite and graphene from graphite. Composites containingthese materials and similar advanced carbon materialshave been tested as electrode materials in EDLCs. I suggest theuse of cellulose nanofibers (CNFs) or microfibrillated cellulose(MFC) as a binder in the electrodes. In addition to improvedmechanical stability, the nanocellulose improved the stabilityof graphite dispersions and the electrical performance of theelectrodes. The influence of the cellulose quality on the electricalproperties of the electrodes and EDLCs was investigated.The results showed that the finest nanocellulose quality is notthe best choice for EDLC electrodes; MFC is recommended forthis application instead. The results also demonstrated thatthe capacitance of EDLCs can be increased if the electrodemasses are adjusted according to the size of the electrolyte ions.Moreover, we investigated the issue of high contact resistancesat the interface between porous carbon electrodes and metalcurrent collectors. To reduce the contact resistance, graphitefoil can be used as a current collector instead of metal foils.Using the suggested low-cost materials, production methodsand conceptual improvements, it is possible to reduce the material costs by more than 90% in comparison with commercialunits. This confirms that paper-based EDLCs are apromising alternative to conventional EDLCs. Our findings andadditional research can be expected to substantially supportthe design and commercialization of sustainable EDLCs andother green energy technologies.
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| 10. |
- 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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