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  • 151.
    Barankova, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bardos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Hollow Cathode and Hybrid Atmospheric Plasma Sources2007In: Proceedings of the: PLENARY PAPER, 2007Conference paper (Refereed)
  • 152.
    Barankova, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bardos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Pulsed Atmospheric Pressure Plasma Reforming Of Ethanol2016In: Hakone XV: International Symposium On High Pressure Low Temperature Plasma Chemistry: With Joint Cost TD1208 Workshop: Non-Equilibrium Plasmas With Liquids For Water And Surface Treatment / [ed] Cernak, M; Hoder, T, 2016, p. 380-381Conference paper (Refereed)
    Abstract [en]

    The plasma source with a coaxial geometry was used for generation of plasma inside water and the ethanol-water mixtures. The hydrogen-rich synthesis gas with hydrogen content up to 60% was produced in submerged dc pulsed plasma. The effect of various plasma generation regimes on the performance of plasma, on the hydrogen production efficiency and on the reaction rise-time was examined. A role of the solution temperature, composition of the mixture and current delivered to the discharge are investigated.

  • 153.
    Barankova, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bardos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Pulsed DC Hollow Cathode Deposition of Cr and CrN Films2007Conference paper (Refereed)
  • 154.
    Barankova, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bardos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Special issue on atmospheric pressure plasma2013In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 234, p. 1-1Article in journal (Other academic)
  • 155.
    Barankova, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. BB Plasma Design AB, SE-75643 Uppsala, Sweden..
    Bardos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. BB Plasma Design AB, SE-75643 Uppsala, Sweden..
    Bardos, A.
    BB Plasma Design AB, SE-75643 Uppsala, Sweden..
    Magnetized hollow cathode activated magnetron2015In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 107, no 15, article id 153501Article in journal (Refereed)
    Abstract [en]

    Planar magnetron in which the target is coupled with a magnetized hollow cathode is presented. Detailed principles of such arrangements are explained. The hollow cathode activated magnetron produces intense and stable plasmas in a wider interval of the working gas pressures as compared to the conventional magnetrons at the same power. The developed arrangements enhance sputtering from the magnetron target by the high-density hollow cathode plasma and increase the number of sputtered/evaporated species. Results of the test experiments of these arrangements on a commercial planar magnetron with the Ti target are presented and their capabilities discussed.

  • 156.
    Barankova, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bardos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Adela
    Reactive Deposition by Magnetron with Magnetized Hollow Cathode Enhanced Target2018Conference paper (Refereed)
  • 157.
    Barankova, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bardos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Silins, Kaspars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Amorphous Carbon Films on Glass Prepared by Hollow Cathodes at Moderate Pressure2016In: ECS Journal of Solid State Science and Technology, ISSN 2162-8769, E-ISSN 2162-8777, Vol. 5, no 9, p. N57-N60Article in journal (Refereed)
  • 158.
    Barankova, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. BB Plasma Design AB, Uppsala, Sweden.
    Bardos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. BB Plasma Design AB, Uppsala, Sweden.
    Silins, Kaspars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bardos, A.
    BB Plasma Design AB.
    Reactive Deposition of TiN Films by Magnetron with Magnetized Hollow Cathode Enhanced Target2018In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 152, p. 123-127Article in journal (Refereed)
    Abstract [en]

    Magnetized Hollow Cathode Activated Magnetron in which the target is coupled with the hollow cathode magnetized by the magnetic field of the magnetron was tested in the reactive process of TiN deposition. Increased deposition rate compared to the Ti metal deposition rate was confirmed. The depositions as well as optical measurements were performed at several pressures in the reactor. The results of the TiN reactive deposition are presented and discussed, including the TiN deposition in pure nitrogen.

  • 159.
    Barati, Paraham
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Research of gravity foundation2010Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The material consumption of the foundation of a WEC is a big part of the totalmaterial consumption of the entire power plant. To reduce these consumption, it isrequired to optimize the foundation. To find out how small the foundation could beconstructed and still be able to cope with the requirements, it is necessary to knowabout the various forces that affects the foundation. The focus in this thesis is on theforces acting on the buoy. The forces are calculated theoretical with experimentsconducted to reach conclusions about the size of the gravity foundation.Experiments will also be conducted to investigate experimentally whether there is anydifference between the suction force of sand and clay soil.Results from experiments with buoys show that the theoretical calculations arereasonably close with results from experiments. Conclusion of the differencesbetween theory and experiment is found that this may be due to the wave tank abilityto reproduce waves, and the angle between the buoy and the wave direction.Results from experiments of the suction force shows that there is no differencebetween sand and clay. The conclusion from this experiment is that the results applyonly to the clay that was investigated in this experiment and cannot be compared withother clay types with different properties.A discussion about the foundations is carried out where the conclusion is drawn thatthe foundations for the minimum mass to maintain equilibrium at 4 m wave height isapproximately 33 ton.

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  • 160.
    Bardos, Ladislav
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Barankova, Hana
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Comparison of Pulsed DC and RF Hollow Cathode Depositions of CrN2007Conference paper (Other academic)
  • 161.
    Bardos, Ladislav
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Barankova, Hana
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Plasma Processes at Atmospheric and Low Pressures2007Conference paper (Refereed)
  • 162.
    Bardos, Ladislav
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Barankova, Hana
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Plasma processes at atmospheric and low pressures2008In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 83, no 3, p. 522-527Article in journal (Refereed)
    Abstract [en]

    In the last few decades there has been an intense development in non-equilibrium ("cold") plasma surface processing systems at atmospheric pressure. This new trend is stimulated mainly to decrease equipment costs by avoiding expensive pumping systems of conventional low-pressure plasma devices. This work summarizes physical and practical limitations where atmospheric plasmas cannot compete with low-pressure plasma and vice-versa. As the processing conditions for atmospheric plasma are rather different from reduced pressure systems in many cases these conditions may increase final equipment costs substantially. In this work we briefly review the main principles, advantages and drawbacks of atmospheric plasma for a better understanding of the capabilities and limitations of the atmospheric plasma processing technology compared with conventional low-pressure plasma processing. 2008 Elsevier Ltd. All rights reserved.

  • 163.
    Bardos, Ladislav
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. BB Plasma Design AB, Ullerakersvagen 64, SE-75643 Uppsala, Sweden..
    Baránková, Hana
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. BB Plasma Design AB, Ullerakersvagen 64, SE-75643 Uppsala, Sweden..
    Bardos, A.
    BB Plasma Design AB, Ullerakersvagen 64, SE-75643 Uppsala, Sweden..
    Production of Hydrogen-Rich Synthesis Gas by Pulsed Atmospheric Plasma Submerged in Mixture of Water with Ethanol2017In: Plasma chemistry and plasma processing, ISSN 0272-4324, E-ISSN 1572-8986, Vol. 37, no 1, p. 115-123Article in journal (Refereed)
    Abstract [en]

    Hydrogen-rich synthesis gas was produced by pulsed dc plasma submerged into ethanol-water mixtures using an original system with a coaxial geometry. The ignition of the discharge is immediately followed by production of hydrogen and after a short time necessary for filling the outlet tubing a flame can be ignited. No auxiliary gas was used for the reforming process. The synthesis gas containing up to 60% of hydrogen was formed, at the outflow rate of 250 sccm at the average power as low as 10 W. The hydrogen production efficiency corresponds to 12 kWh/kg H-2.

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    fulltext
  • 164.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bardos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Hollow cathode and hybrid atmospheric plasma sources2008In: Pure and Applied Chemistry, ISSN 0033-4545, E-ISSN 1365-3075, Vol. 80, no 9, p. 1931-1937Article in journal (Refereed)
    Abstract [en]

    Generation and features of the radio frequency (RF) hollow cathode discharge (HCD) are compared for the atmospheric and moderate pressures. The atmospheric-pressure plasma systems, fused hollow cathode (FHC) and hybrid hollow electrode-activated discharge (H-HEAD), are described. Examples of applications where both FHC and H-HEAD have already been employed are given, and potentials for new processes are discussed.

  • 165.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. BB Plasma Design AB, Ullerakersvagen 64, SE-75643 Uppsala, Sweden.
    Bardos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. BB Plasma Design AB, Ullerakersvagen 64, SE-75643 Uppsala, Sweden.
    Bardos, Adela
    BB Plasma Design AB, Ullerakersvagen 64, SE-75643 Uppsala, Sweden.
    Non-Conventional Atmospheric Pressure Plasma Sources for Production of Hydrogen2018In: MRS Advances, E-ISSN 2059-8521, Vol. 3, no 18, p. 921-929Article in journal (Refereed)
    Abstract [en]

    The atmospheric pressure plasma sources with a coaxial geometry were used for generation of the radio frequency, microwave and pulsed dc plasmas inside water and aqueous solutions. Pulsed dc plasma generated in ethanol-water mixtures leads to production of the hydrogen-rich synthesis gas with hydrogen content up to 65 % The effect of various plasma generation regimes on the performance of plasma, on the hydrogen production efficiency and on the hydrogen-rich synthesis gas production was examined. A role of the composition of the ethanol-water mixture was investigated.

  • 166.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bardos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Silins, Kaspars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    DLC coatings prepared by hollow cathodes at moderate pressure2015Conference paper (Other academic)
    Abstract [en]

    DLC coatings were prepared using the rf powered cylindrical and linear hollow cathodes. The deposition process is hybrid, combining both the PE CVD and PVD. A cylindrical graphite nozzle and graphite plates were used as targets. The gas mixture used in the deposition process was argon with acetylene.

     

    Compared to e.g. magnetron sputtering, the optimum content of acetylene is lower. The effect of the acetylene content in the gas mixture as well as rf power on the deposition rate and properties of the coatings are evaluated.

     

    The geometrical effect is studied, the cylindrical hollow cathode and the linear hollow cathode are compared and the transfer of the optimized process from the cylindrical into the linear hollow cathode is discussed.

    Download full text (pdf)
    fulltext
  • 167.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bardos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Silins, Silins
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    DLC coatings prepared by hollow cathodes at moderate pressure2015Conference paper (Other academic)
    Abstract [en]

    DLC coatings were prepared using the rf powered cylindrical and linear hollow cathodes. The deposition process is hybrid, combining both the PE CVD and PVD. A cylindrical graphite nozzle and graphite plates were used as targets. The gas mixture used in the deposition process was argon with acetylene.

     

    Compared to e.g. magnetron sputtering, the optimum content of acetylene is lower. The effect of the acetylene content in the gas mixture as well as rf power on the deposition rate and properties of the coatings are evaluated.

     

    The geometrical effect is studied, the cylindrical hollow cathode and the linear hollow cathode are compared and the transfer of the optimized process from the cylindrical into the linear hollow cathode is discussed.

  • 168.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bàrdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Atmospheric pressure plasma conversion of CO2 to solid deposits2015In: Results in Physics, ISSN 2211-3797, Vol. 5, p. 257-258Article in journal (Refereed)
    Abstract [en]

    Fused Hollow Cathode (FHC) with aerodynamic stabilization was used for the gas conversion processes. During the conversion of NO into NO2 in air mixtures, the CO2 reduction occurs, without forming gaseous CO. In these processes brownish glassy solid deposits are formed in the plasma region. The deposits were analyzed by scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction.

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    fulltext
  • 169.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Atmospheric Pressure Plasma Sources and Processing2009In: Handbook of Deposition Technologies for Films and Coatings / [ed] Peter M. Martin, Oxford: Elsevier, William Andrew , 2009, 3, p. 865-880Chapter in book (Other (popular science, discussion, etc.))
  • 170.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Cold Atmospheric Plasma in Liquids2012Conference paper (Refereed)
  • 171.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Cold Atmospheric Plasma Inside Water2012Conference paper (Refereed)
  • 172.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Cold Atmospheric Plasma Processing of Inner Surfaces: INVITED PAPER2012Conference paper (Other academic)
  • 173.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Cold Atmospheric Plasma Treatment of Energy System Components: INVITED PAPER2010Conference paper (Other academic)
  • 174.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Convergion of Nitrogen Oxides by the Atmospheric Hollow Cathode Discharges: INVITED PAPER2010In: IEEE 37th International Conference on Plasma Science, Norfolk, Virginia, USA, 2010Conference paper (Other academic)
  • 175.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Conversion of Nitrogen and Carbon Oxides by the Atmospheric Hollow Cathode Discharges2012In: IEEE Transactions on Plasma Science, ISSN 0093-3813, E-ISSN 1939-9375, Vol. 40, no 5, p. 1324-1328Article in journal (Refereed)
    Abstract [en]

    We have successfully tested the fused hollow cathode with aerodynamic stabilization as a 100% oxidation catalyst in conversion of NOx in air mixtures. Plasma chemical kinetics and the processing window width are controlled by plasma characteristics. Results show that, besides the plasma source design itself, the material of the electrodes plays a crucial role. It was found that, by using graphite electrodes, a 100% removal of NO from the air mixtures is possible without necessity of adding hydrocarbons. This paper presents results of oxygen screening, discusses the mechanisms of the process, and reports also on the CO2 reduction in some discharge regimes.

  • 176.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Design and Applications of the Atmospheric Pressure Hollow Cathodes2008Conference paper (Other academic)
  • 177.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Design and Performance of the Hollow Cathode Cold Atmospheric Plasma Sources2008In: Jahrbuch Oberflächentechnik 2008-BAND 64 / [ed] R. Suchentrunk, Bad Saulgau: Eugen G. Leuze Verlag KG , 2008Chapter in book (Refereed)
  • 178.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Effect of the Electrode Material in the Atmospheric Plasma Abatement of Nitrogen Oxides: Paper SE -MoA32009Conference paper (Other academic)
  • 179.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Effect of the Electrode Material on the Atmospheric Plasma Conversion of NO in Air Mixtures2009Conference paper (Refereed)
  • 180.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Effect of the electrode material on the atmospheric plasma conversion of NO in air mixtures2010In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 84, no 12, p. 1385-1388Article in journal (Refereed)
    Abstract [en]

    Non-thermal atmospheric pressure plasma is widely used for conversion of hazardous gases. Results from different laboratories confirm importance of energy non-equilibrium in the plasma where dominant energy carriers are electrons and a dominant chemistry is based on formation and interactions of radicals. Because of rather high electric fields required for generation and sustaining of air discharges at atmospheric pressure many plasma systems were found rather to create a lot of NO instead of removing it. A widely supported way to clean NO and NO2 from air mixtures is a plasma assisted catalytic reduction where the cold plasma is combined with the solid-state catalyst. In an ideal case the plasma acts as an oxidation catalyst where an atomic oxygen from air oxidizes NO to NO2 and the solid-state catalysts are then capable to convert all NO2 to N-2 and O-2. In most cases it is also necessary to involve auxiliary gases, e.g., propylene, to make the process efficient enough. This work introduces an original cold plasma system based on atmospheric hollow cathodes generated by a nanopulse DC power with controllable voltage and pulse frequency. The system was optimized in both the geometry and the applied power. However, the material of electrodes was found to be the most important factor affecting the plasma performance and consequently the chemical kinetics. A 100% conversion of NO to NO2 was achieved with a graphite electrode, without using any auxiliary gas and without catalyst. Plasma performance and conversion efficiency are compared for several electrode materials.

  • 181.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Environmental Applications of the Atmospheric Pressure Plasma Sources: Paper JAPT-112009Conference paper (Refereed)
  • 182.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Hollow Cathode and Hybrid Plasma Processing at Low and High Pressures2008Conference paper (Refereed)
  • 183.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Hollow Cathode High Density Plasma PVD of Cr and CrN films2008Conference paper (Refereed)
  • 184.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    New plasma sources for atmospheric pressure applications2008Conference paper (Refereed)
  • 185.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Non-thermal atmospheric plasma: Sources, processes and applications, INVITED PAPER2011In: Encontro de Física, Foz do Iguacu, Brazil, Foz do Iguacu, Brazil, 2011Conference paper (Refereed)
  • 186.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Optimal Dimensions of the Atmospheric Hollow Cathodes2008Conference paper (Refereed)
  • 187.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Optimization and performance of atmospheric Fused Hollow Cathodes2013In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 87, p. 128-131Article in journal (Refereed)
    Abstract [en]

    Experimental results on the atmospheric hollow cathode plasma generation and performance, using a special configuration with tunable wall separations, are presented. The influence of the gas and type of the power used for generation on the optimum size of the cathode slit is investigated. The experimental results are in agreement with the hollow cathode model. The plasma source/plasma reactor design is of utmost importance for control of plasma-chemical kinetics. An example of the atmospheric hollow cathode plasma application for the NOx conversion is given. The energy consumption and plasma characteristics are discussed.

  • 188.
    Baránková, Hana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bárdos, Ladislav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bergkvist, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Waters, Rafael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Grabbe, Mårten
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Leijon, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Coatings for Renewable Energy: Paper JAPT-142009Conference paper (Refereed)
  • 189. Batten, W.M.J.
    et al.
    Harrison, M.E.
    Bahaj, A. S.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    The accuracy of the actuator disc-RANS approach for predicting the performance and far wake of a horizontal axis tidal stream turbine2013In: Philosophical Transactions. Series A: Mathematical, physical, and engineering science, ISSN 1364-503X, E-ISSN 1471-2962Article in journal (Refereed)
    Abstract [en]

    The actuator disc-RANS model has been widely used in wind and tidal energy to predict the wake of a horizontal axis turbine. The model is appropriate where large scale effects of the turbine on a flow are of interest, for example, when considering environmental impacts, or arrays of devices. The accuracy of the model for modelling the wake of tidal stream turbines has not been demonstrated, and flow predictions presented in the literature for similar modelled scenarios vary significantly. This paper compares the results of the actuator disc-RANS model, where the turbine forces have been derived using a blade element approach, to experimental data measured in the wake of a scaled turbine. It also compares the results to those of a simpler uniform actuator disc model. The comparisons show that the model is accurate and can predict up to 94\% of the variation in the experimental data measured on the centreline of the wake. The study demonstrates that the actuator-disc RANS model is an accurate approach for modelling a turbine wake, and conservative approach to predict performance and loads. It can therfore applied to similar scenarios with confidence.

  • 190.
    Baudoin, Antoine
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Cooling Strategies for Wave Power Conversion Systems2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Division for Electricity of Uppsala University is developing a wave power concept. The energy of the ocean waves is harvested with wave energy converters, consisting of one buoy and one linear generator. The units are connected in a submerged substation. The mechanical design is kept as simple as possible to ensure reliability.

    The submerged substation includes power electronics and different types of electrical power components. Due to the high cost of maintenance operations at sea, the reliability of electrical systems for offshore renewable energy is a major issue in the pursuit of making the electricity production economically viable. Therefore, proper thermal management is essential to avoid the components being damaged by excessive temperature increases.

    The chosen cooling strategy is fully passive, and includes no fans. It has been applied in the second substation prototype with curved heatsinks mounted on the inner wall of the pressurized vessel. This strategy has been evaluated with a thermal model for the completed substation. First of all, 3D-CFD models were implemented for selected components of the electrical conversion system. The results from these submodels were used to build a lumped parameter model at the system level.

    The comprehensive thermal study of the substation indicates that the rated power in the present configuration is around 170 kW. The critical components were identified. The transformers and the inverters are the limiting components for high DC-voltage and low DC-voltage respectively. The DC-voltage—an important parameter in the control strategy for the WEC—was shown to have the most significant effect on the temperature limitation.

    As power diodes are the first step of conversion, they are subject to large power fluctuations. Therefore, we studied thermal cycling for these components. The results indicated that the junction undergoes repeated temperature cycles, where the amplitude increased with the square root of the absorbed power.

    Finally, an array of generic heat sources was optimized. We designed an experimental setup to investigate conjugate natural convection on a vertical plate with flush-mounted heat sources. The influence of the heaters distribution was evaluated for different dissipated powers. Measurements were used for validation of a CFD model. We proposed optimal distributions for up to 36 heat sources. The cooling capacity was maximized while the used area was minimized.

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  • 191.
    Baudoin, Antoine
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thermal Study of a Submerged Substation for Wave Power2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    At the Division of Electricity of Uppsala University, a wave power concept is being developed.It relies on wave energy converters, one buoy and one linear generator placed on the seabed, connected together to a submerged substation. The mechanical design is kept as simple as possible to ensure reliability. The submerged substation includes power electronics and different types of electric components. High reliability requirements on such subsea devices make thermal management a keyaspect in the design. Besides, no fans are used and the cooling strategy is fully-passive. The overall approach for thermal modelling of the substation is based on a thermal network atthe system level, and both analytic- and CFD- modelling at the component level. This work is focusing on the second prototype of substation developed at Uppsala University. In this thesis, this overall strategy is presented as well as a comprehensive temperature study for the inverterinstalled in the substation.In the present configuration, the inverters are limited to about 35 kW. The seawater temperature,the choice of material for the heat-sink, and the spacing of the component, were identified tohave an influence on this value. The importance of a good thermal contact between the heat-sink and the hull was also illustrated.

  • 192.
    Baudoin, Antoine
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thermal modelling of a passively cooled inverter for wave power2015In: IET Renewable Power Generation, ISSN 1752-1416, E-ISSN 1752-1424, Vol. 9, no 4, p. 389-395Article in journal (Refereed)
    Abstract [en]

    Owing to very costly maintenance operations, the reliability of electrical systems for offshore renewable energy is a major issue to make electricity production economical. Therefore proper thermal management is essential in order to avoid the components from being damaged by excessive temperature increase. Both analytic and computational fluid dynamics (CFD) models were implemented to assess the temperature increase in the inverter installed in a submerged substation and during working conditions. It was shown that this inverter could transmit a total power of up to about 35 kW. This limit is dependent on a certain distance between the modules and a perfect thermal contact with the hull. The influence of several of such parameters as well as the efficiency of passive cooling were studied.

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  • 193.
    Baudoin, Antoine
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Leijon, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thermal Rating of a Submerged Substation for Wave Power2016In: IEEE Transactions on Sustainable Energy, ISSN 1949-3029, E-ISSN 1949-3037, Vol. 7, no 1, p. 436-445Article in journal (Refereed)
    Abstract [en]

    The costs of offshore maintenance operations put high reliability-requirements on offshore equipment for ocean energy, especially on submerged ones. Thermal management is thus essential in the design of the prototypes of a marine substation, developed at Uppsala University, for grid interface of wave power parks. The cooling system itself should be efficient as well as reliable. Therefore, the feasibility of a completely passive cooling strategy was evaluated. The studied substation includes various power components, which dissipate heat and are installed in one pressurized vessel. Thermal cross-coupling was investigated with 3-D submodels and a thermal network model. An electric circuit was coupled to determine the rated power of the substation. The results depend mainly on the dc-voltage, the seawater temperature, and the thermal contact between the components and the hull.

  • 194.
    Baudoin, Antoine
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Saury, Didier
    Assessment of Thermal Cycling in a Rectifier For WavePower Generation2016Conference paper (Refereed)
    Abstract [en]

    Natural convection allows for passive cooling which isused in many engineering applications. Placing dissipatingcomponents on a common vertical heatsink can be opti-mized to give the best possible cooling capacity. In thisstudy, a numerical model for three-dimensional conjugatedconvective and conductive heat transfer was used to evalu-ate the distribution of up to 36 ush-mounted rectangularheaters. The temperature proles and the heat uxes werecompared with experimental data for validation. The dis-sipated power was set as an input parameter and the op-timal distribution was selected as the one with the lowesttemperature elevation. Two dierent heuristicsa geo-metric parameter and an articial neural networkwereproposed and evaluated as alternatives to heavy CFD cal-culations.

  • 195.
    Baudoin, Antoine
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Ekström, Rickard
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Rahm, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Svensson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Strömstedt, Erland
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Savin, Andrej
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Waters, Rafael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Leijon, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Temperature Study in a Marine Substation for Wave Power2012In: International Journal of Mechanic Systems Engineering, ISSN 2225-7403, Vol. 2, no 4, p. 126-131Article in journal (Refereed)
  • 196.
    Baudoin, Antoine
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Saury, Didier
    Univ Poitiers, ENSMA, CNRS, Inst PPRIME, BP 40109, F-86961 Futuroscope, France.
    Temperature and velocity measurements in a buoyant flow induced by a heat source array on a vertical plate2017In: Experimental Thermal and Fluid Science, ISSN 0894-1777, E-ISSN 1879-2286, Vol. 88, p. 234-245Article in journal (Refereed)
    Abstract [en]

    Heat source arrays are common in engineering applications. Natural convection is a reliable and silent cooling strategy. Therefore, an array of flush-mounted heat sources has been studied under conjugate conduction and natural convection condition. This studies was performed for a system with relatively large dimensions, typical for power electronics, and a modified Rayleigh number up to 2 . 10(10) A modular set of heaters was designed to vary the distribution of heat sources on the plate and investigate the influence of the spacing. Velocity and temperature were measured in the convective flow with particle image velocimetry and micro-thermocouple. The velocity field was analyzed with proper orthogonal decomposition. The first instabilities of the convective flows were described. The results gave abetter understanding of the heat transfers in these configurations and are valuable for model validation.

  • 197.
    Baudoin, Antoine
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Saury, Didier
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Optimized distribution of a large number of heat sources cooled by conjugate turbulent natural convectionIn: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606Article in journal (Refereed)
  • 198.
    Baudoin, Antoine
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Saury, Didier
    Univ Poitiers, ENSMA, CNRS, Inst PPRIME, BP 40109, F-86961 Futuroscope, France..
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Optimized distribution of a large number of power electronics components cooled by conjugate turbulent natural convection2017In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 124, p. 975-985Article in journal (Refereed)
    Abstract [en]

    Natural convection allows for passive cooling which is used in many engineering applications. Placing dissipating components on a common vertical heatsink can be optimized to give the best possible cooling capacity. In this study, a numerical model for three-dimensional conjugated convective and conductive heat transfer was used to evaluate the distribution of up to 36 flush-mounted rectangular heaters. The temperature profiles and the heat fluxes were compared with experimental data for validation. The dissipated power was set as an input parameter and the optimal distribution was selected as the one with the lowest temperature elevation. Two different heuristics-a geometric parameter and an artificial neural network-were proposed and evaluated as alternatives to heavy CFD calculations.

  • 199.
    Baudoin, Antoine
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Saury, Didier
    Univ Poitiers, ENSMA, CNRS, Inst PPRIME, BP 40109, F-86961 Futuroscope, Chassencuil, France.
    Zhu, Bo
    Univ Poitiers, ENSMA, CNRS, Inst PPRIME, BP 40109, F-86961 Futuroscope, Chassencuil, France.
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Experimental Optimization of Passive Cooling of a Heat Source Array Flush-Mounted on a Vertical Plate2016In: Energies, E-ISSN 1996-1073, Vol. 9, no 11, article id 912Article in journal (Refereed)
    Abstract [en]

    Heat sources, such as power electronics for offshore power, could be cooled passively—mainly by conduction and natural convection. The obvious advantage of this strategy is its high reliability. However, it must be implemented in an efficient manner (i.e., the area needs to be kept low to limit the construction costs). In this study, the placement of multiple heat sources mounted on a vertical plate was studied experimentally for optimization purposes. We chose a regular distribution, as this is likely to be the preferred choice in the construction process. We found that optimal spacing can be determined for a targeted source density by tuning the vertical and horizontal spacing between the heat sources. The optimal aspect ratio was estimated to be around two.

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  • 200.
    Bayazit, Dervis
    et al.
    Federal Home Loan Bank of Atlanta, Financial Risk Modeling Department, Atlanta GA.
    Uzunoglu, Bahri
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Simplex optimization for particle filter joint parameter estimation of electricity prices with jump diffusion2013In: Journal of financial and economic practice, Vol. 13, no 2, p. 1-14Article in journal (Refereed)
1234567 151 - 200 of 1787
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