| 1. |
- Sume, Ain, et al.
(författare)
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Radar Detection of Moving Targets Behind Corners
- 2011
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Ingår i: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING. - : IEEE; 1999. - 0196-2892. ; 49:6, s. 2259-2267
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Tidskriftsartikel (refereegranskat)abstract
- Detection of moving objects concealed behind a concrete wall corner has been demonstrated, using Doppler-based techniques with a stepped-frequency radar centered at 10 GHz, in a reduced-scale model of a street scenario. Micro-Doppler signatures have been traced in the return from a human target, both for walking and for breathing. Separate material measurements of the reflection and transmission of the concrete in the wall have showed that wall reflections are the dominating wave propagation mechanism for producing target detections, while wave components transmitted through the walls could be neglected. Weaker detections have been made of target returns via diffraction in the wall corner. A simple and fast algorithm for the detection and generation of detection tracks in down range has been developed, based on moving target indication technique.
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| 2. |
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| 3. |
- Boström, Cecilia, et al.
(författare)
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Temperature measurements in a linear generator and marine substation for wave power
- 2010
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Ingår i: PROCEEDINGS OF THE ASME 29TH INTERNATIONAL CONFERENCE ON OCEAN, OFFSHORE AND ARCTIC ENGINEERING 2010, VOL 3. - 9780791849118 ; , s. 545-552
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Konferensbidrag (refereegranskat)abstract
- This paper analyzes temperature measurements acquired in offshore operation of a wave energy converter array. The three directly driven wave energy converters have linear generators and are connected to a marine substation placed on the seabed. The highly irregular individual linear generator voltages are rectified and added on a common DC-link and inverted to 50 Hz to facilitate future grid-connection. The electrical power is transmitted to shore and converted to heat in a measuring station. First results of temperature measurements on substation components and on the stator of one of the linear generators are presented from operation in linear and in non-linear damping. Results indicate that there might be some convective heat transport in the substation vessel. If high power levels are extracted from the waves, this has to be considered when placing components in the substation vessel to avoid heating from neighbouring components. The results also indicate that the temperature increase in the linear generator stator is very small. Failure due to excessive heating of the stator winding PVC cable insulation is unlikely to occur even in very energetic sea states. Should this conclusion be incorrect, the thermal conductivity between the stator and the hull of the WEC could be enhanced. Another suggested alteration would be to lower the resistive losses by reducing the linear generator current density.
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| 4. |
- Boström, Cecilia, et al.
(författare)
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Temperature measurements in a linear generator and marine substation for wave power
- 2012
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Ingår i: Journal of Offshore Mechanics and Arctic Engineering-Transactions of The Asme. - : ASME International. - 0892-7219 .- 1528-896X. ; 134:2, s. 021901-
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Tidskriftsartikel (refereegranskat)abstract
- This paper analyzes temperature measurements acquired in the offshore operation of a wave energy converter array. The three directly driven wave energy converters have linear generators and are connected to a marine substation placed on the seabed. The highly irregular individual linear generator voltages are rectified and added on a common dc-link and inverted to 50 Hz to facilitate future grid-connection. The electrical power is transmitted to shore and converted to heat in a measuring station. The first results of temperature measurements on substation components and on the stator of one of the linear generators are presented based on operation in linear and in nonlinear damping. The results indicate that there might be some convective heat transfer in the substation vessel. If high power levels are extracted from the waves, this has to be considered when placing components in the substation vessel in order to avoid heating from neighboring components. The results also indicate that the temperature increase in the linear generator stator is very small. Failure due to excessive heating of the stator winding polyvinyl chloride cable insulation is unlikely to occur even in very energetic sea states. Should this conclusion be incorrect, the thermal conductivity between the stator and the hull of the wave energy converter could be enhanced. Another suggested alteration is to lower the resistive losses by reducing the linear generator current density.
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| 5. |
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| 6. |
- Evegren, Franz, et al.
(författare)
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Fire testing of external combustible ship surfaces
- 2014
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Ingår i: Proceedings of 11th International Symposium on Fire Safety Science. Christchurch, New Zealand. 2014-02-13. - : International Association for Fire Safety Science. ; , s. 905-918
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Konferensbidrag (refereegranskat)abstract
- Reduced weight makes use of fiber reinforced polymer composite desirable in maritime construction applications. Exterior ship surfaces in combustible materials are although not covered by firesafety regulations and their fire protection is therefore a key issue. This paper reports how SP FIRE 105, a standardized test method for testing reaction to fire properties of façade systems, was adjusted and used to evaluate the potential for fire growth on external combustible ship surfaces; in particular fiber reinforced polymer composite surfaces protected with active or passive measures. The trials show that the test method is highly suitable but that some adjustments could be made to reduce uncertainties; in particular to use a gas burner instead of a heptane pool fire source and to add a strong criterion for when to activate active measures. Further efforts should also be made to develop suitable performance criteria, which were suggested to be based on the produced heat and the gas temperatures at the top of the panel.
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| 7. |
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| 8. |
- Krishna, Remya, 1985-, et al.
(författare)
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Analysis of linear wave power generator model with real sea experimental results
- 2013
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Ingår i: IET Renewable Power Generation. - : Institution of Engineering and Technology (IET). - 1752-1416 .- 1752-1424. ; 7:5, s. 574-581
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Tidskriftsartikel (refereegranskat)abstract
- This study presents the dynamic modelling of a linear permanent magnet generator for extracting energy from ocean waves. Translator position, calculated from measured generator voltage, is used as input for the simulation model. Instantaneous power from the simulation model has been compared with the measurements from the Lysekil research site. The power output from the model considering the air gap flux variation is precisely matching with the measured values before core saturation. The generator dynamic model is modified by including the saturation effect. Although a simple mathematical expression is considered for representing the saturation, the model gives accurate power spectrum close to the experimental results. The presented model is a first step towards the system model that can simulate the entire electric system including electric grid. As such, the generator model can be used for further analysis of the wave energy conversion system.
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| 9. |
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| 10. |
- Lonne-Rahm, Sol-Britt, et al.
(författare)
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Adult atopic dermatitis patients and physical exercise : a Swedish questionnaire study.
- 2014
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Ingår i: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 0001-5555 .- 1651-2057. ; 94:2, s. 185-7
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Tidskriftsartikel (refereegranskat)abstract
- Physical activity promotes health and prevents disease. When patients with atopic dermatitis (AD) undertake exercise, the itch often gets worse due to sweating, and this may reduce their engagement in physical exercise. The aim of this study was to determine the level of physical exercise in patients with AD compared with a control group from a normal population. Our hypothesis was that patients with AD have a lower level of physical exercise due to their skin disease. A total of 110 patients with AD and 196 subjects from a normal population, age range 20-34 years, answered a questionnaire. Eleven patients with AD underwent an in-depth interview. The patients with AD had the same level of physical exercise and attitude to physical exercise as the normal population. Therefore, our hypothesis could not be confirmed. In conclusion, the skin symptoms of AD do not appear to be an obstacle to moderate physical exercise.
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