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  • 51.
    Backman, Fredrick
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Från föhn till feu!: Esrange och den norrländska rymdverksamhetens tillkomsthistoria från sekelskiftet 1900 till 19662010Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This essay is about the origin, planning and establishment of the European Space Research Organisation's (ESRO) sounding rocket base Esrange outside Kiruna in Northern Sweden. Three main questions are examined. First I show there were not just scientific and technical but also political, economical as well as military reasons to build a European rocket base. Second, I scrutinize the reasons to choose Northern Sweden as the location for the rocket base. As it turns out, the main reasons were the favourable location of Northern Sweden within the aurora oval zone, the proximity of the Kiruna Geophysical Observatory, and the possibility to use a large, although not quite uninhabited, area where the launched rockets could crash. Finally, I examine the difficulty of talking about boundaries of various kinds, such as temporal, spatial and functional. The essay also provides a discussion on possible ways to continue research on this topic.

  • 52.
    Baer, Katharina
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Fluida och mekatroniska system. Linköpings universitet, Tekniska fakulteten.
    Simulation-Based Optimization of a Series Hydraulic Hybrid Vehicle2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Hybrid transmissions are characterized by their utilization of more than one form of energy storage. They have the potential to help reduce overall fuel consumption and vehicle emissions by providing the possibility of brake energy recuperation and prime mover operation management. Electric hybrids and electric vehicle drives are nowadays ubiquitous, and mechanical energy storage in flywheel has been investigated in the past. The use of fluid power technology with a combustion engine has also been investigated since the late 1970s, and is frequently revisited.

    Hydraulic hybridization is especially attractive for heavy vehicles with frequent braking and acceleration which benefit most from fluid power components’ high power density, typically busses, delivery or refuse vehicles, and vehicles with existing hydraulic circuits and transmissions, such as forest and construction machinery, but have been considered for smaller vehicles as well.

    Due to the characteristic discharge profile of hydraulic energy storage, special attention needs to be paid to control aspects in the design process to guarantee drivability of the vehicle. In this respect, simulation models can be of use in early design process stages for cheaper and faster evaluation of concepts and designs than physical experiments and prototyping, and to generate better understanding of the system studied. Engineering optimization aids in the systematic exploration of a given design space, to determine limits and potentials, evaluate trade-offs and potentially find unexpected solutions. In the optimization of a hydraulic hybrid transmission, the integration of component and controller design is of importance, and different strategies (sequential, iterative, bi-level and simultaneous approaches) are conceivable, with varying consequences for the implementation.

    This thesis establishes a simulation-based optimization framework for a hydraulic hybrid transmission with series architecture. Component and control parameter optimization are addressed simultaneously, using a rule-based supervisory control strategy. The forward-facing dynamic simulation model at the centre of the framework is built in Hopsan, a multi-disciplinary open-source tool developed at Linköping University. The optimization is set up and conducted for an example application of an on-road light-duty truck over standard drive cycles. Both results from these experiments as well as the framework itself are studied and evaluated. Relevant design aspects, such as explicit design relations to be considered and performance requirements for more robust design, are identified and addressed, and the optimization problem is analysed with regard to algorithm performance and problem formulation. The final result is an optimization framework that can be adjusted for further in-depth studies, for example through the inclusion of additional components or optimization objectives, and extendable for comparative analysis of different topologies, applications and problem formulations.  

  • 53.
    Ballard, Claire
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Conceptual lay-out of small launcher2012Självständigt arbete på avancerad nivå (masterexamen), 30 poäng / 45 hpStudentuppsats (Examensarbete)
  • 54.
    Ballard, Claire
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Conceptual lay-out of small launcher2012Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The objective of this diploma thesis is to perform a conceptual lay-out of a small launcher. Re- quirements have been defined in order to realize this first preliminary study and design of a small launcher. In that frame, a MATLAB code has been written in order to simulate the rocket tra- jectories. An optimization program on launcher staging has been written as well. To validate this code, the VEGA and Ariane 5 launchers have been used. Then from studies on existing launchers, simulations have been performed in order to find an optimum small launcher and later on to design more precisely the small launcher. As a requirement an upper stage has been newly designed for the purpose of the study. At the end, two small launchers have been considered: a three-stage launcher using the Zefiro 23 as a first stage, the Zefiro 9 as a second stage, and an upper stage using a 3kN thrust engine; a two-stage launcher using the Zenit booster engine in the first stage, and an upper stage using a 22kN thrust engine.

  • 55. Balmer, G.
    et al.
    Berquand, A.
    Company-Vallet, E.
    Granberg, V.
    Grigore, V.
    Ivchenko, Nickolay
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Kevorkov, R.
    Lundkvist, E.
    Olentsenko, Georgi
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Pacheco-Labrador, J.
    Tibert, Gunnar
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Yuan, Yunxia
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    ISAAC: A REXUS STUDENT EXPERIMENT TO DEMONSTRATE AN EJECTION SYSTEM WITH PREDEFINED DIRECTION2015Ingår i: EUROPEAN ROCKET AND BALLOON: PROGRAMMES AND RELATED RESEARCH, 2015, s. 235-242Konferensbidrag (Refereegranskat)
    Abstract [en]

    ISAAC - Infrared Spectroscopy to Analyse the middle Atmosphere Composition was a student experiment launched from SSC's Esrange Space Centre, Sweden, on 29th May 2014, on board the sounding rocket REXUS 15 in the frame of the REXUS/BEXUS programme. The main focus of the experiment was to implement an ejection system for two large Free Falling Units (FFUs) (240 mm x 80 mm) to be ejected from a spinning rocket into a predefined direction. The system design relied on a spring-based ejection system. Sun and angular rate sensors were used to control and time the ejection. The flight data includes telemetry from the Rocket Mounted Unit (RMU), received and saved during flight, as well as video footage from the GoPro camera mounted inside the RMU and recovered after the flight. The FFUs' direction, speed and spin frequency as well as the rocket spin frequency were determined by analyzing the video footage. The FFU-Rocket-Sun angles were 64.3 degrees and 104.3 degrees, within the required margins of 90 degrees +/- 45 degrees. The FFU speeds were 3.98 m/s and 3.74 m/s, lower than the expected 5 +/- 1 m/s. The FFUs' spin frequencies were 1.38 Hz and 1.60 Hz, approximately half the rocket's spin frequency. The rocket spin rate slightly changed from 3.163 Hz before the ejection to 3.117 Hz after the ejection of the two FFUs. The angular rate, sun sensor data and temperature on the inside of the rocket module skin were also recorded. The experiment design and results of the data analysis are presented in this paper.

  • 56. Barabash, Victoria
    A comparison of PMSE occurrence with energetic particle precipitation detected by riometer in northern Scandinavia2000Ingår i: Proceedings of the 9th International Workshop on Technical and Scientific Aspects of MST Radar- MST9 combined with COST-76 Final Profiler Workshop: Toulouse, France, March 13-18, 2000 / [ed] Belva Edwards, Toulouse: SCOSTEP , 2000Konferensbidrag (Övrigt vetenskapligt)
  • 57. Barabash, Victoria
    Are variations in PMSE intensity affected by energetic particle precipitation?2002Ingår i: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 20, s. 539-545Artikel i tidskrift (Refereegranskat)
  • 58. Barabash, Victoria
    ESRAD MST radar analysis of the waves1998Ingår i: Proceedings of the 4th European Symposium on Stratospheric Ozone, Air Pollution Research Report 66, European Commision, 1998, s. 70-73Konferensbidrag (Övrigt vetenskapligt)
  • 59. Barabash, Victoria
    Leewave observations by the MST radar ESRAD in northen Sweden1999Ingår i: Mesoscale processes in the stratosphere: their effect on the stratospheric chemistry and microphysics ; proceedings of the European workshop 8 to 11 November 1998 Bad Tölz, Bavaria, Germany / [ed] K.S. Carslaw ; G.T. Amanatidis, Luxemourg: European Commission Joint Research Centre, 1999, s. 233-238Konferensbidrag (Övrigt vetenskapligt)
  • 60. Barabash, Victoria
    MST radar observations of PMSE in Northern Scandinavia during May-August 19971998Ingår i: Proceedings of the Eigth Workshop on Technical and Scientific Aspects of MST Radar : solar-terrestrial energy program: solar-terrestrial energy program ; Bangalore, India, December 15 - 20, 1997 / [ed] Belva Edwards, Boulder, Colo.: SCOSTEP , 1998, s. 326-329Konferensbidrag (Övrigt vetenskapligt)
  • 61. Barabash, Victoria
    MST-radar lee wave ovservations during winter 1996/97 in northern Scandinavia1997Ingår i: Proceedings of 13th ESA Symposium on Rocket and Baloon Programmes and Related Research, ESA-SP-397, 1997, s. 179-183Konferensbidrag (Övrigt vetenskapligt)
  • 62. Barabash, Victoria
    Wind profiling with ESRAD, the Esrange radar1997Ingår i: Extended abstracts COST-76 Profiler Workshop: v / [ed] Hans Richner, Zürich: Eidgenössische Technische Hochschule (ETH), Institute for Atmospheric Science , 1997, s. 70-73Konferensbidrag (Övrigt vetenskapligt)
  • 63. Barabash, Victoria
    et al.
    Chilson, P.
    Kirkwood, S.
    Réchou, A.
    Stebel, K.
    Investigations of the possible relationship between PMSE and tides using a VHF MST radar1998Ingår i: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 25, nr 17, s. 3297-3300Artikel i tidskrift (Refereegranskat)
  • 64.
    Barabash, Victoria
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Ejemalm, Johnny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Kuhn, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Milz, Mathias
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Molin, Sven
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Johansson, Jonny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Westerberg, Lars-Göran
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Masters Programs in Space Science and Engineering in Northern Sweden2017Konferensbidrag (Refereegranskat)
  • 65. Barabash, Victoria
    et al.
    Kirkwood, S.
    Feofilov, A.
    Kutepov, A.
    Polar mesosphere summer echoes during the July 2000 solar proton event2004Ingår i: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 22, nr 3, s. 759-771Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The influence of the solar proton event (SPE) 14-16 July 2000 on Polar Mesosphere Summer Echoes (PMSE) is examined. PMSE were observed by the Esrange VHF MST Radar (ESRAD) at 67°53'N, 21°06'E. The 30MHz Imaging Riometer for Ionospheric Studies IRIS in Kilpisjärvi (69°30'N, 20°47'E) registered cosmic radio noise absorption caused by ionisation changes in response to the energetic particle precipitation. An energy deposition/ion-chemical model was used to estimate the density of free electrons and ions in the upper atmosphere. Particle collision frequencies were calculated from the MSISE-90 model. Electric fields were calculated using conductivities from the model and measured magnetic disturbances. The electric field reached a maximum of 91mV/m during the most intensive period of the geomagnetic storm accompanying the SPE. The temperature increase due to Joule and particle heating was calculated, taking into account radiative cooling. The temperature increase at PMSE heights was found to be very small. The observed PMSE were rather intensive and extended over the 80-90km height interval. PMSE almost disappeared above 86km at the time of greatest Joule heating on 15 July 2000. Neither ionisation changes, nor Joule/particle heating can explain the PMSE reduction. Transport effects due to the strong electric field are a more likely explanation.

  • 66.
    Barabash, Victoria
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Osepian, A.
    Polar Geophysical Institute, Murmansk.
    Dalin, P.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Kirkwood, S.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Electron density profiles in the quiet lower ionosphere based on the results of modeling and experimental data2012Ingår i: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 30, nr 9, s. 1345-1360Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The theoretical PGI (Polar Geophysical Institute) model for the quiet lower ionosphere has been applied for computing the ionization rate and electron density profiles in the summer and winter D-region at solar zenith angles less than 80° and larger than 99° under steady state conditions. In order to minimize possible errors in estimation of ionization rates provided by solar electromagnetic radiation and to obtain the most exact values of electron density, each wavelength range of the solar spectrum has been divided into several intervals and the relations between the solar radiation intensity at these wavelengths and the solar activity index F10.7 have been incorporated into the model. Influence of minor neutral species (NO, H2O, O, O3) concentrations on the electron number density at different altitudes of the sunlit quiet D-region has been examined. The results demonstrate that at altitudes above 70 km, the modeled electron density is most sensitive to variations of nitric oxide concentration. Changes of water vapor concentration in the whole altitude range of the mesosphere influence the electron density only in the narrow height interval 73-85 km. The effect of the change of atomic oxygen and ozone concentration is the least significant and takes place only below 70 km. Model responses to changes of the solar zenith angle, solar activity (low-high) and season (summer-winter) have been considered. Modeled electron density profiles have been evaluated by comparison with experimental profiles available from the rocket measurements for the same conditions. It is demonstrated that the theoretical model for the quiet lower ionosphere is quite effective in describing variations in ionization rate, electron number density and effective recombination coefficient as functions of solar zenith angle, solar activity and season. The model may be used for solving inverse tasks, in particular, for estimations of nitric oxide concentration in the mesosphere

  • 67.
    Barabash, Victoria
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Osepian, Aleftina
    Polar Geophysical Institute, Murmansk.
    Dalin, Peter
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Influence of water vapour on the height distribution of positive ions, effective recombination coefficient and ionisation balance in the quiet lower ionosphere2014Ingår i: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 32, s. 207-222Artikel i tidskrift (Refereegranskat)
  • 68.
    Barake, Mohammed
    Mälardalens högskola, Akademin för innovation, design och teknik.
    PW120 Motorprestanda, matchning av motorn, samt mätverktyg för HPT, LPT och PT blad2014Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
  • 69.
    Barghouthi, Imad A.
    et al.
    Space Research Lab, Department of Physics, Al-Quds University, Jerusalem, Department of Physics, Al-Quds University, Jerusalem.
    Abudayyeh, H.A.
    Department of Physics, Al-Quds University, Jerusalem.
    Slapak, Rikard
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Nilsson, Hans
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    O+ and H+ above the polar cap: Observations and semikinetic simulations2016Ingår i: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 121, nr 1, s. 459-474Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A 1-dimensional direct simulation Monte Carlo model is used to study the outflow of O+ and H+ ions from 1.2 RE to 15.2 RE along two flight trajectories originating from the polar cap, namely the central polar cap (CPC) and the cusp. To study the effect of varying geophysical conditions and to deduce the proper set of parameters. several parameters were varied and the results were compared to corresponding data from Cluster spacecraft. First, several sets of diffusion coefficients were considered based on using diffusion coefficients calculated by Barghouthi et al. [1998], Nilsson et al. [2013], and Abudayyeh et al. [2015b] for different altitude intervals. It was found that in the central polar cap using the diffusion coefficients reported by Barghouthi et al. [1998] for altitudes lower than 3.7 RE, zero diffusion coefficients between 3.7 and 7.5 RE and diffusion coefficients from Nilsson et al. [2013] for altitudes higher than 7.5 RE provide the best fit for O+ ions. For O+ ions in the cusp the best fit was obtained for using Barghouthi et al. [1998] diffusion coefficients for altitudes lower than 3.7 RE and Nilsson et al. [2013] diffusion coefficients for altitudes higher than that. The best fit for H+ ions in both regions was obtained by using the diffusion coefficients calculated by Abudayyeh et al. [2015b]. Also, it was found that along an ion's trajectory the most recent heating dominates. Second, the strength of centrifugal acceleration was varied by using three values for the ionospheric electric field namely: 0, 50, and 100 mV/m. It was found that the value of 50 mV/m provided the best fit for both ion species in both regions. Finally the lower altitude boundary conditions and the electron temperature were varied. Increasing the electron temperature and the lower altitude O+ parallel velocity were found to increase the access of O+ ions to higher altitudes and therefore increase the density at a given altitude. The variation of all other boundary conditions only affected the densities of the ions and not the other moments due to the overwhelming effect of wave particle interaction. Furthermore varying the parameters of one ion species has no effect on the other ion species. We also compared the energy gain per ion due to wave particle interaction, centrifugal acceleration, and ambipolar electric field and found that wave particle interaction is the most important mechanism, while ambipolar electric field is relatively unimportant especially at higher altitudes.

  • 70.
    Baron, P.
    et al.
    National Institute of Information and Communications Technology, 4-2-1 Nukui-kitamachi, Koganei.
    Urban, J.
    Chalmers University of Technology.
    Sagawa, H.
    National Institute of Information and Communications Technology, 4-2-1 Nukui-kitamachi, Koganei.
    Möller, J.
    Chalmers University of Technology.
    Mendrok, Jana
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Dupuy, E.
    Sato, T.O,
    Ochiai, Satoshi
    National Institute of Information and Communication Technology, Tokyo.
    Suzuk, K.
    Manabe, T.
    Osaka Prefecture University, Naka, Sakai.
    Nishibori, T.
    Japan Aerospace Exploration Agency (JAXA), Tsukuba.
    Kikuchi, K.
    Sato, R.
    Takayanagi, M.
    Murayama, Y.
    Shiotani, M.
    Research Institute for Sustainable Humanosphere, Kyoto University.
    Kasai, Y.
    The Level 2 research product algorithms for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES)2011Ingår i: Atmospheric Measurement Techniques, ISSN 1867-1381, E-ISSN 1867-8548, Vol. 4, s. 2105-2124Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper describes the algorithms of the level-2 research (L2r) processing chain developed for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES). The chain has been developed in parallel to the operational chain for conducting researches on calibration and retrieval algorithms. L2r chain products are available to the scientific community. The objective of version 2 is the retrieval of the vertical distribution of trace gases in the altitude range of 18–90 km. A theoretical error analysis is conducted to estimate the retrieval feasibility of key parameters of the processing: line-of-sight elevation tangent altitudes (or angles), temperature and ozone profiles. While pointing information is often retrieved from molecular oxygen lines, there is no oxygen line in the SMILES spectra, so the strong ozone line at 625.371 GHz has been chosen. The pointing parameters and the ozone profiles are retrieved from the line wings which are measured with high signal to noise ratio, whereas the temperature profile is retrieved from the optically thick line center. The main systematic component of the retrieval error was found to be the neglect of the non-linearity of the radiometric gain in the calibration procedure. This causes a temperature retrieval error of 5–10 K. Because of these large temperature errors, it is not possible to construct a reliable hydrostatic pressure profile. However, as a consequence of the retrieval of pointing parameters, pressure induced errors are significantly reduced if the retrieved trace gas profiles are represented on pressure levels instead of geometric altitude levels. Further, various setups of trace gas retrievals have been tested. The error analysis for the retrieved HOCl profile demonstrates that best results for inverting weak lines can be obtained by using narrow spectral windows.

  • 71.
    Baron, P.
    et al.
    National Institute of Information and Communications Technology, 4-2-1 Nukui-kitamachi, Koganei.
    Urban, J.
    Chalmers University of Technology.
    Sagawa, H.
    National Institute of Information and Communications Technology, 4-2-1 Nukui-kitamachi, Koganei.
    Möller, J.
    Chalmers University of Technology.
    Murtagh, D.P.
    Chalmers University of Technology.
    Mendrok, Jana
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Dupuy, E.
    National Institute of Information and Communications Technology, 4-2-1 Nukui-kitamachi, Koganei.
    Sato, T.O.
    National Institute of Information and Communications Technology, 4-2-1 Nukui-kitamachi, Koganei.
    Ochiai, S.
    National Institute of Information and Communications Technology, 4-2-1 Nukui-kitamachi, Koganei.
    Suzuki, K.
    National Institute of Information and Communications Technology, 4-2-1 Nukui-kitamachi, Koganei.
    Manabe, T.
    Osaka Prefecture University, Naka, Sakai.
    Nishibori, T.
    Japan Aerospace Exploration Agency (JAXA), Tsukuba.
    Kikuchi, K.
    Japan Aerospace Exploration Agency (JAXA), Tsukuba.
    Sato, R.
    Japan Aerospace Exploration Agency (JAXA), Tsukuba.
    Takayanagi, M.
    Japan Aerospace Exploration Agency (JAXA), Tsukuba.
    Murayama, Y.
    National Institute of Information and Communications Technology, 4-2-1 Nukui-kitamachi, Koganei.
    Shiotani, M.
    Research Institute for Sustainable Humanosphere, Kyoto University.
    Kasai, Y.
    National Institute of Information and Communications Technology, 4-2-1 Nukui-kitamachi, Koganei.
    The level 2 research product algorithms for the superconducting submillimeter-wave limb-emission sounder (SMILES)2011Ingår i: Atmospheric Measurement Techniques Discussions, ISSN 1867-8610, E-ISSN 1867-8610, Vol. 4, nr 3, s. 3593-3645Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper describes the algorithms of the level-2 research (L2r) processingchain developed for the Superconducting Submillimeter-Wave Limb-EmissionSounder (SMILES). The chain has been developed in parallel to the operationalchain for conducting researches on calibration and retrieval algorithms. L2rchain products are available to the scientific community. The objective ofversion 2 is the retrieval of the vertical distribution of trace gases in thealtitude range of 18-90 km. An theoretical error analysis is conducted toestimate the retrieval feasibility of key parameters of the processing:line-of-sight elevation tangent altitudes (or angles), temperature and O3 profiles. The line-of-sight tangent altitudes are retrievedbetween 20 and 50 km from the strong ozone (O3) line at 625.371 GHz,with low correlation with the O3 volume-mixing ratio and temperatureretrieved profiles. Neglecting the non-linearity of the radiometric gain inthe calibration procedure is the main systematic error. It is large for theretrieved temperature (between 5-10 K). Therefore, atmospheric pressure cannot be derived from the retrieved temperature, and, then, in the altituderange where the line-of-sight tangent altitudes are retrieved, the retrievedtrace gases profiles are found to be better represented on pressure levelsthan on altitude levels. The error analysis for the retrieved HOCl profiledemonstrates that best results for inverting weak lines can be obtained byusing narrow spectral windows. Future versions of the L2r algorithms willimprove the temperature/pressure retrievals and also provide information inthe upper tropospheric/lower stratospheric region (e.g., water vapor, icecontent, O3) and on stratospheric and mesospheric line-of-sight winds.

  • 72.
    Barquin Murguia, Alberto Isaac
    Luleå tekniska universitet, Institutionen för system- och rymdteknik. Airbus DS.
    SmallSat Payload Simulation for Onboard-Software Verification2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This work presents the advancements in the development of simulation models of spacecraft components as part of a testbench for verification of onboard flight software. The satellite and its mission are briefly described as to give an idea of the conditions where the simulation has to run. The simulation environment, SimTG, is also introduced and a description of the developed models is presented. The models required interaction between different simulation environments, real hardware and simulated hardware, and also some data processing was necessary in order to filter undesired information. Finally, the performance of the models was tested and verified and a sensible improvement of the state of the testbench on the simulation side was achieved, although a considerable amount of work still lies ahead before a complete onboard software verification tool is ready.

  • 73.
    Barrére, Vincent
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Viability of CREO Simulate: (CAD software’s module) as a thermal simulation software2019Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The analysis of the reliability of CREO simulate will be done step by step. First of all, the precisionof the simulation has to be measured thus a comparison with simple theoretical computations willbe done. Then, the scope of the capacity of the software will be analyzed and if elements deemednecessary to thermal simulations are missing, back up solutions are to be found. Also, the influenceof the meshing will be studied and measured to ensure that the software guarantee convergence evenin the hand of persons unfamiliar with simulations.In parallel, one will experiment with realistic hardware that could be used to compare reality withthe simulations. Those experiments will be handmade using regular materials from the company.

  • 74.
    Bazzocchi, Michael C. F.
    et al.
    University of Toronto, Institute for Aerospace Studies.
    Emami, Reza
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. University of Toronto.
    Asteroid detumbling for redirection missions2018Ingår i: 2018 IEEE Aerospace Conference, IEEE Computer Society, 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    In order to accomplish most asteroid redirection missions, rotational control of the asteroid body is required. Small near-Earth asteroids tend to exhibit a significant range of rotational and tumbling properties. This work provides an analysis of asteroid detumbling using a formation of spacecraft. Through an orbiter and three landed thruster spacecraft, a low-thrust detumbling maneuver is performed on two illustrative asteroids. The asteroid scenarios are designed such that they reflect the characteristics of possible redirection scenarios. In particular the geometries, densities, angular velocities, and masses of the asteroids are adjusted according to available asteroid data to provide two unique redirection scenarios. The asteroid and spacecraft specifications are outlined, as well as the formulations for the detumbling maneuver. The results of the maneuver are discussed along with the key detumbling parameters and timeframe required.

  • 75.
    Beaty, D.W
    et al.
    Jet Propulsion Laboratory, California Institute of Technology.
    Fernández-Remolar, David
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Zorzano Mier, María-Paz
    Centro de Astrobiologia.
    The potential science and engineering value of samples delivered to Earth by Mars sample return2019Ingår i: Meteoritics and Planetary Science, ISSN 1086-9379, E-ISSN 1945-5100, Vol. 54, nr 3, s. 667-671Artikel i tidskrift (Refereegranskat)
  • 76.
    Beaty, D.W
    et al.
    Jet Propulsion Laboratory, California Institute of Technology.
    Fernández-Remolar, David
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Zorzano Mier, María-Paz
    Centro de Astrobiologia.
    The potential science and engineering value of samples delivered to Earth by Mars sample return: International MSR Objectives and Samples Team (iMOST)2019Ingår i: Meteoritics and Planetary Science, ISSN 1086-9379, E-ISSN 1945-5100, Vol. 54, nr S1, s. 3-152Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Executive Summary: Return of samples from the surface of Mars has been a goal of the international Mars science community for many years. Affirmation by NASA and ESA of the importance of Mars exploration led the agencies to establish the international MSR Objectives and Samples Team (iMOST). The purpose of the team is to re-evaluate and update the sample-related science and engineering objectives of a Mars Sample Return (MSR) campaign. The iMOST team has also undertaken to define the measurements and the types of samples that can best address the objectives. Seven objectives have been defined for MSR, traceable through two decades of previously published international priorities. The first two objectives are further divided into sub-objectives. Within the main part of the report, the importance to science and/or engineering of each objective is described, critical measurements that would address the objectives are specified, and the kinds of samples that would be most likely to carry key information are identified. These seven objectives provide a framework for demonstrating how the first set of returned Martian samples would impact future Martian science and exploration. They also have implications for how analogous investigations might be conducted for samples returned by future missions from other solar system bodies, especially those that may harbor biologically relevant or sensitive material, such as Ocean Worlds (Europa, Enceladus, Titan) and others. Summary of Objectives and Sub-Objectives for MSR Identified by iMOST: Objective 1 Interpret the primary geologic processes and history that formed the Martian geologic record, with an emphasis on the role of water. Intent To investigate the geologic environment(s) represented at the Mars 2020 landing site, provide definitive geologic context for collected samples, and detail any characteristics that might relate to past biologic processesThis objective is divided into five sub-objectives that would apply at different landing sites. 1.1 Characterize the essential stratigraphic, sedimentologic, and facies variations of a sequence of Martian sedimentary rocks. Intent To understand the preserved Martian sedimentary record. Samples A suite of sedimentary rocks that span the range of variation. Importance Basic inputs into the history of water, climate change, and the possibility of life 1.2 Understand an ancient Martian hydrothermal system through study of its mineralization products and morphological expression. Intent To evaluate at least one potentially life-bearing “habitable” environment Samples A suite of rocks formed and/or altered by hydrothermal fluids. Importance Identification of a potentially habitable geochemical environment with high preservation potential. 1.3 Understand the rocks and minerals representative of a deep subsurface groundwater environment. Intent To evaluate definitively the role of water in the subsurface. Samples Suites of rocks/veins representing water/rock interaction in the subsurface. Importance May constitute the longest-lived habitable environments and a key to the hydrologic cycle. 1.4 Understand water/rock/atmosphere interactions at the Martian surface and how they have changed with time. Intent To constrain time-variable factors necessary to preserve records of microbial life. Samples Regolith, paleosols, and evaporites. Importance Subaerial near-surface processes could support and preserve microbial life. 1.5 Determine the petrogenesis of Martian igneous rocks in time and space. Intent To provide definitive characterization of igneous rocks on Mars. Samples Diverse suites of ancient igneous rocks. Importance Thermochemical record of the planet and nature of the interior. Objective 2 Assess and interpret the potential biological history of Mars, including assaying returned samples for the evidence of life. Intent To investigate the nature and extent of Martian habitability, the conditions and processes that supported or challenged life, how different environments might have influenced the preservation of biosignatures and created nonbiological “mimics,” and to look for biosignatures of past or present life.This objective has three sub-objectives: 2.1 Assess and characterize carbon, including possible organic and pre-biotic chemistry. Samples All samples collected as part of Objective 1. Importance Any biologic molecular scaffolding on Mars would likely be carbon-based. 2.2 Assay for the presence of biosignatures of past life at sites that hosted habitable environments and could have preserved any biosignatures. Samples All samples collected as part of Objective 1. Importance Provides the means of discovering ancient life. 2.3 Assess the possibility that any life forms detected are alive, or were recently alive. Samples All samples collected as part of Objective 1. Importance Planetary protection, and arguably the most important scientific discovery possible. Objective 3 Quantitatively determine the evolutionary timeline of Mars. Intent To provide a radioisotope-based time scale for major events, including magmatic, tectonic, fluvial, and impact events, and the formation of major sedimentary deposits and geomorphological features. Samples Ancient igneous rocks that bound critical stratigraphic intervals or correlate with crater-dated surfaces. Importance Quantification of Martian geologic history. Objective 4 Constrain the inventory of Martian volatiles as a function of geologic time and determine the ways in which these volatiles have interacted with Mars as a geologic system. Intent To recognize and quantify the major roles that volatiles (in the atmosphere and in the hydrosphere) play in Martian geologic and possibly biologic evolution. Samples Current atmospheric gas, ancient atmospheric gas trapped in older rocks, and minerals that equilibrated with the ancient atmosphere. Importance Key to understanding climate and environmental evolution. Objective 5 Reconstruct the processes that have affected the origin and modification of the interior, including the crust, mantle, core and the evolution of the Martian dynamo. Intent To quantify processes that have shaped the planet's crust and underlying structure, including planetary differentiation, core segregation and state of the magnetic dynamo, and cratering. Samples Igneous, potentially magnetized rocks (both igneous and sedimentary) and impact-generated samples. Importance Elucidate fundamental processes for comparative planetology. Objective 6 Understand and quantify the potential Martian environmental hazards to future human exploration and the terrestrial biosphere. Intent To define and mitigate an array of health risks related to the Martian environment associated with the potential future human exploration of Mars. Samples Fine-grained dust and regolith samples. Importance Key input to planetary protection planning and astronaut health. Objective 7 Evaluate the type and distribution of in-situ resources to support potential future Mars exploration. Intent To quantify the potential for obtaining Martian resources, including use of Martian materials as a source of water for human consumption, fuel production, building fabrication, and agriculture. Samples Regolith. Importance Production of simulants that will facilitate long-term human presence on Mars. Summary of iMOST Findings: Several specific findings were identified during the iMOST study. While they are not explicit recommendations, we suggest that they should serve as guidelines for future decision making regarding planning of potential future MSR missions. The samples to be collected by the Mars 2020 (M-2020) rover will be of sufficient size and quality to address and solve a wide variety of scientific questions. Samples, by definition, are a statistical representation of a larger entity. Our ability to interpret the source geologic units and processes by studying sample sub sets is highly dependent on the quality of the sample context. In the case of the M-2020 samples, the context is expected to be excellent, and at multiple scales. (A) Regional and planetary context will be established by the on-going work of the multi-agency fleet of Mars orbiters. (B) Local context will be established at field area- to outcrop- to hand sample- to hand lens scale using the instruments carried by M-2020. A significant fraction of the value of the MSR sample collection would come from its organization into sample suites, which are small groupings of samples designed to represent key aspects of geologic or geochemical variation. If the Mars 2020 rover acquires a scientifically well-chosen set of samples, with sufficient geological diversity, and if those samples were returned to Earth, then major progress can be expected on all seven of the objectives proposed in this study, regardless of the final choice of landing site. The specifics of which parts of Objective 1 could be achieved would be different at each of the final three candidate landing sites, but some combination of critically important progress could be made at any of them. An aspect of the search for evidence of life is that we do not know in advance how evidence for Martian life would be preserved in the geologic record. In order for the returned samples to be most useful for both understanding geologic processes (Objective 1) and the search for life (Objective 2), the sample collection should contain BOTH typical and unusual samples from the rock units explored. This consideration should be incorporated into sample selection and the design of the suites. The retrieval missions of a MSR campaign should (1) minimize stray magnetic fields to which the samples would be exposed and carry a magnetic witness plate to record exposure, (2) collect and return atmospheric gas sample(s), and (3) collect additional dust and/or regolith sample mass if possible.

  • 77.
    Behar, Etienne
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Solar Wind Dynamics within The Atmosphere of comet 67P/Churyumov-Gerasimenko2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    I  denna  avhandling  undersöks  solvindens  dynamik  när  den  flödar genom  en  tunn  kometatmosfär,  med  fokus  på  den  interaktion  somobserverats vid kometen 67P/Churyumov-Gerasimenko.

    När  Rosetta  nådde  from  till  komet  67P/Churyumov–Gerasimenko  i augusti 2014 hade redan sju olika rymdfarkoster besökt nio olika ko- meter.  Rosetta  var  dock  den  första  missionen  som  cirklade  runt  en komet och följde den sedan i dess bana i totalt mer än två år. Detta motsvarade en signifikant del av hela kometens bana runt solen. Det- ta gjorde det möjligt att studera plasmats dynamiska utveckling un- der en period när kometen utvecklades från ett av de minsta hindren solvinden möter i solsystemet, när kometen är långt från solen, till enfullt utvecklad magnetosfär nära perihelion.

    Avhandlingen behandlar främst den tidiga delen av denna utveckling, när nyligen joniserade molekyler från kometatmosfären börjar ge en signifikant störning i solvindens flöde. Under dessa förhållanden är en kinetisk beskrivning av växelverkan mellan solvinden och kome- tatmosfären  nödvändig.  Systemet  vi  studerar  kan  inte  reduceras  till ett hydrodynamiskt problem. Detta till skillnad från situationen när kometen är närmare solen, då växelverkan kan beskrivas med fluid- teori, för både Churyumov–Gerasimenko och de tidigare undersöktakometerna.

    Rosetta var inte en mission främst ägnad åt plasma-studier. Detta med- förde begränsad rumslig täckning av de plasma-processer som äger rum, vilka äger rum över flera olika rumsskalor. Att förstå solvindens växleverkan  med  kometatmosfären  enbart  med  enpunktsmätningar låter sig därför inte göras. I detta arbete används därför en kombina- tion av experimentella data, analytiska beskrivningar och numeriska beräkningar. I kapitel 3 och 4 föreslår vi enkla modeller för att beskri- va jondynamiken och kometens plasmamiljö. Dessa testas sedan mot observationer och numeriska modeller. Tillsammans ger de en global beskrivning  av  solvindens  dynamik  när  den  flödar  genom  kometat- mosfären,  vilket  utforskas  i  både  2 och  3 dimensioner  (kapitel  5).  I kapitel 6 utforskar vi interaktionen som sker när kometen är närmaresolen, och hur den nu i högre grad kan beskrivas som en fluid.

  • 78.
    Behar, Etienne
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Lindkvist, Jesper
    Swedish Institute of Space Physics, Kiruna.
    Nilsson, Hans
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Holmström, Mats
    Swedish Institute of Space Physics, Kiruna.
    Stenberg-Wieser, G.
    Swedish Institute of Space Physics, Kiruna.
    Ramstad, Robin
    Swedish Institute of Space Physics, Kiruna.
    Götz, C.
    Technicsche Universität Braunschweig, Institute for Geophysics and Extraterrestrial Physics, Braunschweig.
    Mass-loading of the solar wind at 67P/Churyumov-Gerasimenko: Observations and modelling2016Ingår i: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 596, artikel-id A42Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Context. The first long-term in-situ observation of the plasma environment in the vicinity of a comet, as provided by the European Rosetta spacecraft. Aims. Here we offer characterisation of the solar wind flow near 67P/Churyumov-Gerasimenko (67P) and its long term evolution during low nucleus activity. We also aim to quantify and interpret the deflection and deceleration of the flow expected from ionization of neutral cometary particles within the undisturbed solar wind. Methods. We have analysed in situ ion and magnetic field data and combined this with hybrid modeling of the interaction between the solar wind and the comet atmosphere. Results. The solar wind deflection is increasing with decreasing heliocentric distances, and exhibits very little deceleration. This is seen both in observations and in modeled solar wind protons. According to our model, energy and momentum are transferred from the solar wind to the coma in a single region, centered on the nucleus, with a size in the order of 1000 km. This interaction affects, over larger scales, the downstream modeled solar wind flow. The energy gained by the cometary ions is a small fraction of the energy available in the solar wind. Conclusions. The deflection of the solar wind is the strongest and clearest signature of the mass-loading for a small, low-activity comet, whereas there is little deceleration of the solar wind

  • 79.
    Behar, Etienne
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Swedish Institute of Space Physics, Kiruna.
    Nilsson, Hans
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Swedish Institute of Space Physics, Kiruna.
    Alho, M.
    Aalto University, School of Electrical Engineering, Department of Electronics and Nanoengineering, Finland.
    Goetz, C.
    Technische Universität Braunschweig, Institute for Geophysics and Extraterrestrial Physics, Germany.
    Tsurutani, B.
    Jet Propulsion Laboratory, California Institute of Technology, USA.
    The birth and growth of a solar wind cavity around a comet: Rosetta observations2017Ingår i: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 469, nr Suppl. 2, s. S369-S403Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Rosetta mission provided detailed observations of the growth of a cavity in the solar wind around comet 67P/Churyumov–Gerasimenko. As the comet approached the Sun, the plasma of cometary origin grew enough in density and size to present an obstacle to the solar wind. Our results demonstrate how the initial slight perturbations of the solar wind prefigure the formation of a solar wind cavity, with a particular interest placed on the discontinuity (solar wind cavity boundary) passing over the spacecraft. The slowing down and heating of the solar wind can be followed and understood in terms of single particle motion. We propose a simple geometric illustration that accounts for the observations, and shows how a cometary magnetosphere is seeded from the gradual steepening of an initially slight solar wind perturbation. A perspective is given concerning the difference between the diamagnetic cavity and the solar wind cavity.

  • 80.
    Behar, Etienne
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Swedish Institute of Space Physics, Kiruna.
    Nilsson, Hans
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Swedish Institute of Space Physics, Kiruna.
    Henri, P.
    LPC2E, CNRS, Orléans.
    Berecic, L.
    Swedish Institute of Space Physics, Kiruna.
    Nicolaou, G.
    Swedish Institute of Space Physics, Kiruna.
    Stenberg-Wieser, G.
    Swedish Institute of Space Physics, Kiruna.
    Wieser, M.
    Swedish Institute of Space Physics, Kiruna.
    Tabone, B.
    LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, UPMC Univ. Paris.
    Saillenfest, M.
    IMCCE, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, UPMC Univ. Paris.
    Goetz, C.
    Technische Universität Braunschweig, Institute for Geophysics and Extraterrestrial Physics.
    The root of a comet tail: Rosetta ion observations at comet 67P/Churyumov–Gerasimenko2018Ingår i: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 616, artikel-id A21Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Context.The first 1000 km of the ion tail of comet 67P/Churyumov–Gerasimenko were explored by the EuropeanRosettaspacecraft,2.7 au away from the Sun.Aims.We characterised the dynamics of both the solar wind and the cometary ions on the night-side of the comet’s atmosphere.Methods.We analysed in situ ion and magnetic field measurements and compared the data to a semi-analytical model.Results.The cometary ions are observed flowing close to radially away from the nucleus during the entire excursion. The solar windis deflected by its interaction with the new-born cometary ions. Two concentric regions appear, an inner region dominated by theexpanding cometary ions and an outer region dominated by the solar wind particles.Conclusions.The single night-side excursion operated byRosettarevealed that the near radial flow of the cometary ions can beexplained by the combined action of three different electric field components, resulting from the ion motion, the electron pressuregradients, and the magnetic field draping. The observed solar wind deflection is governed mostly by the motional electric field−uion×B.

  • 81.
    Behar, Etienne
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Nilsson, Hans
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Wieser, Gabriella Stenberg
    Swedish Institute of Space Physics.
    Nemeth, Zoltan
    Wigner Research Centre for Physics, 1121 Konkoly Thege Street 29-33, Budapest.
    Brolles, T.W.
    Space Science and Engineering Division, Southwest Research Institute, San Antonio.
    Richter, Ingo
    Technische Universität–Braunschweig, Institute for Geophysics and Extraterrestrial Physics.
    Mass loading at 67P/Churyumov-Gerasimenko: A case study2016Ingår i: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 43, nr 4, s. 1411-1418Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We study the dynamics of the interaction between the solar wind ions and a partially ionized atmosphere around a comet, at a distance of 2.88 AU from the Sun during a period of low nucleus activity. Comparing particle data and magnetic field data for a case study, we highlight the prime role of the solar wind electric field in the cometary ion dynamics. Cometary ion and solar wind proton flow directions evolve in a correlated manner, as expected from the theory of mass loading. We find that the main component of the accelerated cometary ion flow direction is along the antisunward direction and not along the convective electric field direction. This is interpreted as the effect of an antisunward polarization electric field adding up to the solar wind convective electric field.

  • 82.
    Behar, Etienne
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Swedish Institute of Space Physics, Kiruna.
    Tabone, B.
    LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, UPMC Univ. Paris.
    Nilsson, Hans
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Swedish Institute of Space Physics, Kiruna.
    Dawn-dusk asymmetry induced by the Parker spiral angle in the plasma dynamics around comet 67P/Churyumov-Gerasimenko2018Ingår i: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 478, nr 2, s. 1570-1575Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    When interacting, the solar wind and the ionised atmosphere of a comet exchange energy and momentum. Our aim is to understand the influence of the average Parker spiral configuration of the solar wind magnetic field on this interaction. We compare the theoretical expectations of an analytical generalised gyromotion with Rosetta observations at comet 67P/Churyumov-Gerasimenko. A statistical approach allows one to overcome the lack of upstream solar wind measurement. We find that additionally to their acceleration along (for cometary pick-up ions) or against (for solar wind ions) the upstream electric field orientation and sense, the cometary pick-up ions are drifting towards the dawn side of the coma, while the solar wind ions are drifting towards the dusk side of the coma, independent of the heliocentric distance. The dynamics of the interaction is not taking place in a plane, as often assumed in previous works.

  • 83.
    Behar, Etienne
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Swedish Institute of Space Physics, Kiruna.
    Tabone, B.
    LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, UPMC Univ. Paris.
    Saillenfest, M.
    IMCCE, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, UPMC Univ. Paris.
    Henri, P.
    LPC2E, CNRS, Orléans.
    Deca, J.
    Laboratory for Atmospheric and Space Physics (LASP), University of Colorado Boulder.
    Lindkvist, J.
    Umeå University, Department of Physics.
    Holmström, Mats
    Swedish Institute of Space Physics, Kiruna.
    Nilsson, Hans
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Swedish Institute of Space Physics, Kiruna.
    Solar wind dynamics around a comet: A 2D semi-analytical kinetic model2018Ingår i: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 620, artikel-id A35Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aims.We aim at analytically modelling the solar wind proton trajectories during their interaction with a partially ionised cometaryatmosphere, not in terms of bulk properties of the flow but in terms of single particle dynamics.Methods.We first derive a generalised gyromotion, in which the electric field is reduced to its motional component. Steady-stateis assumed, and simplified models of the cometary density and of the electron fluid are used to express the force experienced byindividual solar wind protons during the interaction.Results.A three-dimensional (3D) analytical expression of the gyration of two interacting plasma beams is obtained. Applying it to acomet case, the force on protons is always perpendicular to their velocity and has an amplitude proportional to 1/r2. The solar winddeflection is obtained at any point in space. The resulting picture presents a caustic of intersecting trajectories, and a circular regionis found that is completely free of particles. The particles do not lose any kinetic energy and this absence of deceleration, togetherwith the solar wind deflection pattern and the presence of a solar wind ion cavity, is in good agreement with the general results of theRosettamission.Conclusions.The qualitative match between the model and thein situdata highlights how dominant the motional electric field isthroughout most of the interaction region for the solar wind proton dynamics. The model provides a simple general kinetic descriptionof how momentum is transferred between these two collisionless plasmas. It also shows the potential of this semi-analytical modelfor a systematic quantitative comparison to the data.

  • 84.
    Bejhed, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialvetenskap. ÅSTC.
    Eriksson, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialvetenskap. ÅSTC.
    Stenmark, L
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialvetenskap. ÅSTC.
    The Development of a Micro Machined Xenon Feed System2004Ingår i: AIAA-2004-3976, 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit: Fort Lauderdale, Florida, USA, 11-14 July 2004, 2004, s. pp 1-8Konferensbidrag (Övrigt vetenskapligt)
  • 85.
    Bejhed, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialvetenskap. ÅSTC.
    Wallbank, J
    Lindegren, Robert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialvetenskap. ÅSTC.
    Thorslund, Robert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialvetenskap. ÅSTC.
    Baker, A M
    Stenmark, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialvetenskap. ÅSTC.
    Köhler, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialvetenskap. ÅSTC.
    Catalyst microsystem design and manufacture for a monopropellant microrocket engine2004Ingår i: PowerMEMS 2004, Kyoto, Japan.: 28-30 November, 2004., 2004Konferensbidrag (Övrigt vetenskapligt)
  • 86.
    Ben Sassi, Amin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Maneekum, Iddaris
    Optimering av B737NG underhållsprogram ur ett tekniskt åtkomstperspektiv2015Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Idag bygger varje flygbolag sitt underhållsprogram baserat på underhållsåtgärdernas tröskelvärden och Repeat intervall. TUIfly Nordics tekniska avdelning har upplevt att liten eller ingen hänsyn har tagits till de olika underhållsåtgärdernas intervall i relation till område på flygplan och åtkomstkrav för att utföra en underhållsåtgärd. Med anledning av detta har vi för detta arbete fått i uppdrag av TUIfly Nordic att utreda huruvida en optimering av underhållsprogrammet för B737NG flottan är möjlig, genom att ta hänsyn till område och åtkomstkrav på planet. Konsekvensen av dagens underhållsprogram är att åtgärder med samma åtkomstkrav ej samordnas. D.v.s. öppning/borttagning av paneler/luckor görs för ofta, vilket kostar bolaget mycket tid och pengar.

    Målet med examensarbetet har varit att identifiera möjliga justeringar i intervall för att planera underhållsåtgärder efter område och åtkomstkrav, så att de görs samtidigt. Genom en datainsamling och analys från diverse litteraturstudier, bolagets och tillverkarens manualer, har TUIfly Nordics problemställning kunnat utredas. En sammanställning av totalt 41 underhållsåtgärder i sju olika områden har redovisats, där en de-eskalering av tröskelvärde är ett alternativ för att samordna underhållsåtgärder som har samma område och åtkomstkrav. Resultatet som presenterats är endast ett koncept och kan därför inte användas direkt, utan en egen utvärdering av TUIfly Nordics tekniska avdelning. Kontentan av detta examensarbete är en rekommendation på hur man lämpligast optimerar ett underhållsprogram för B737NG medtaget hänsyn till område och åtkomstkrav, vilket var målsättningen och det önskade resultatet med arbetet.

  • 87.
    BENETHUILLERE, Quentin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Revision Of The Aircraft Engines Preliminary Design Platform Of First Level2014Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In the highly competitive aerospace industry, engine manufacturers must react very quickly and precisely to any demand emerging from aircraft manufacturers if they want to be positioned on the offer. This is especially true when answering to Requests For Information (RFI) based on preliminary design investigations of first level. In order to reduce the time needed to perform these costly operations while improving the performances achieved, Snecma wishes to develop tools for dimensioning the engine and also for assessing key parameters such as mass, emissions, fuel burn, costs, etc. Unfortunately, the set of tools and the process used at the present time for preliminary design investigations of first level are not sufficient to meet the high standards sought-after by the company in terms of time and performances. As a consequence, efforts must be spent on redefining the whole process and the tools it is based on; here is the mission that has been conferred upon me.

     

    Multiple exchanges with performances engineers and specialists allowed to draw the current process for preliminary design investigations of first level and raise all the associated concerns. At the same time, a status of the existing tools (called modules in this report), mainly developed under Excel, has been realised in order to identify the range of action for today's investigations. A prototype has been developed under SDK Python with the aim of proving the feasibility of a solution to a difficulty that shows up in the process for each new investigation: the one of generating the workflow on the optimisation software Optimus. A target process has finally been discussed considering all the information collected, and would allow dividing by five the time needed to perform investigations compare to now. The prototype developed lead to interesting results and this solution could thus probably be integrated in the target process as it would allow saving one day of work for an engineer for each study to be carried out.

     

    Solutions have been proposed to all the concerns identified in the process and they will have to be discussed with many actors and investigated further in the near future in order to set the target process that will allow meeting the final objective of answering all types of RFIs emitted by aircraft manufacturer in a very short time with a high level of confidence in the results.

     

  • 88.
    BENETHUILLERE, Quentin
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Revision Of The Aircraft Engines Preliminary Design Platform Of First Level2014Självständigt arbete på avancerad nivå (masterexamen), 20hpStudentuppsats (Examensarbete)
    Abstract [en]

    In the highly competitive aerospace industry, engine manufacturers must react very quickly and precisely to any demand emerging from aircraft manufacturers if they want to be positioned on the offer. This is especially true when answering to Requests For Information (RFI) based on preliminary design investigations of first level. In order to reduce the time needed to perform these costly operations while improving the performances achieved, Snecma wishes to develop tools for dimensioning the engine and also for assessing key parameters such as mass, emissions, fuel burn, costs, etc. Unfortunately, the set of tools and the process used at the present time for preliminary design investigations of first level are not sufficient to meet the high standards sought-after by the company in terms of time and performances. As a consequence, efforts must be spent on redefining the whole process and the tools it is based on; here is the mission that has been conferred upon me.

     

    Multiple exchanges with performances engineers and specialists allowed to draw the current process for preliminary design investigations of first level and raise all the associated concerns. At the same time, a status of the existing tools (called modules in this report), mainly developed under Excel, has been realised in order to identify the range of action for today's investigations. A prototype has been developed under SDK Python with the aim of proving the feasibility of a solution to a difficulty that shows up in the process for each new investigation: the one of generating the workflow on the optimisation software Optimus. A target process has finally been discussed considering all the information collected, and would allow dividing by five the time needed to perform investigations compare to now. The prototype developed lead to interesting results and this solution could thus probably be integrated in the target process as it would allow saving one day of work for an engineer for each study to be carried out.

     

    Solutions have been proposed to all the concerns identified in the process and they will have to be discussed with many actors and investigated further in the near future in order to set the target process that will allow meeting the final objective of answering all types of RFIs emitted by aircraft manufacturer in a very short time with a high level of confidence in the results.

  • 89.
    BENETHUILLERE, Quentin
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Revision Of The Aircraft Engines Preliminary Design Platform Of First Level2014Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In the highly competitive aerospace industry, engine manufacturers must react very quickly and precisely to any demand emerging from aircraft manufacturers if they want to be positioned on the offer. This is especially true when answering to Requests For Information (RFI) based on preliminary design investigations of first level. In order to reduce the time needed to perform these costly operations while improving the performances achieved, Snecma wishes to develop tools for dimensioning the engine and also for assessing key parameters such as mass, emissions, fuel burn, costs, etc. Unfortunately, the set of tools and the process used at the present time for preliminary design investigations of first level are not sufficient to meet the high standards sought-after by the company in terms of time and performances. As a consequence, efforts must be spent on redefining the whole process and the tools it is based on; here is the mission that has been conferred upon me.

     

    Multiple exchanges with performances engineers and specialists allowed to draw the current process for preliminary design investigations of first level and raise all the associated concerns. At the same time, a status of the existing tools (called modules in this report), mainly developed under Excel, has been realised in order to identify the range of action for today's investigations. A prototype has been developed under SDK Python with the aim of proving the feasibility of a solution to a difficulty that shows up in the process for each new investigation: the one of generating the workflow on the optimisation software Optimus. A target process has finally been discussed considering all the information collected, and would allow dividing by five the time needed to perform investigations compare to now. The prototype developed lead to interesting results and this solution could thus probably be integrated in the target process as it would allow saving one day of work for an engineer for each study to be carried out.

     

    Solutions have been proposed to all the concerns identified in the process and they will have to be discussed with many actors and investigated further in the near future in order to set the target process that will allow meeting the final objective of answering all types of RFIs emitted by aircraft manufacturer in a very short time with a high level of confidence in the results.

  • 90.
    Bengtsson Bernander, Karl
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion.
    A Method for Detecting Resident Space Objects and Orbit Determination Based on Star Trackers and Image Analysis2014Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Satellites commonly use onboard digital cameras, called star trackers. A star tracker determines the satellite's attitude, i.e. its orientation in space, by comparing star positions with databases of star patterns. In this thesis, I investigate the possibility of extending the functionality of star trackers to also detect the presence of resident space objects (RSO) orbiting the earth. RSO consist of both active satellites and orbital debris, such as inactive satellites, spent rocket stages and particles of different sizes.

    I implement and compare nine detection algorithms based on image analysis. The input is two hundred synthetic images, consisting of a portion of the night sky with added random Gaussian and banding noise. RSO, visible as faint lines in random positions, are added to half of the images. The algorithms are evaluated with respect to sensitivity (the true positive rate) and specificity (the true negative rate). Also, a difficulty metric encompassing execution times and computational complexity is used.

    The Laplacian of Gaussian algorithm outperforms the rest, with a sensitivity of 0.99, a specificity of 1 and a low difficulty. It is further tested to determine how its performance changes when varying parameters such as line length and noise strength. For high sensitivity, there is a lower limit in how faint the line can appear.

    Finally, I show that it is possible to use the extracted information to roughly estimate the orbit of the RSO. This can be accomplished using the Gaussian angles-only method. Three angular measurements of the RSO positions are needed, in addition to the times and the positions of the observer satellite. A computer architecture capable of image processing is needed for an onboard implementation of the method.

  • 91.
    Benini, E.
    University of Padova, Italy.
    Advances in Gas Turbine Technology2011Samlingsverk (redaktörskap) (Refereegranskat)
  • 92.
    Berecic, Laura
    et al.
    Swedish Institute of Space Physics, Kiruna.
    Behar, Etienne
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Swedish Institute of Space Physics, Kiruna.
    Nilsson, Hans
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Swedish Institute of Space Physics, Kiruna.
    Nicolaou, G.
    Swedish Institute of Space Physics, Kiruna.
    Stenberg-Wieser, G.
    Swedish Institute of Space Physics, Kiruna.
    Wieser, M.
    Swedish Institute of Space Physics, Kiruna.
    Goetz, C.
    Technische Universität Braunschweig, Institute for Geophysics and Extraterrestrial Physics.
    Cometary ion dynamics observed in the close vicinity of comet 67P/Churyumov-Gerasimenko during the intermediate activity period2018Ingår i: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 613, s. 1-8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aims.Cometary ions are constantly produced in the coma, and once produced they are accelerated and eventually escape the coma.We describe and interpret the dynamics of the cometary ion flow, of an intermediate active comet, very close to the nucleus and in theterminator plane.Methods.We analysed in situ ion and magnetic field measurements, and characterise the velocity distribution functions (mostly usingplasma moments). We propose a statistical approach over a period of one month.Results.On average, two populations were observed, separated in phase space. The motion of the first is governed by its interactionwith the solar wind farther upstream, while the second one is accelerated in the inner coma and displays characteristics compatiblewith an ambipolar electric field. Both populations display a consistent anti-sunward velocity component.Conclusions.Cometary ions born in different regions of the coma are seen close to the nucleus of comet 67P/Churyumov–Gerasimenko with distinct motions governed in one case by the solar wind electric field and in the other case by the position relative tothe nucleus. A consistent anti-sunward component is observed for all cometary ions. An asymmetry is found in the average cometaryion density in a solar wind electric field reference frame, with higher density in the negative (south) electric field hemisphere. Thereis no corresponding signature in the average magnetic field strengt

  • 93.
    Berg, Kim
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Peerzadah, Wais
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Implementering av MSG-3 process på traktionsmotor LJE108-12012Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    För operatören är det viktigt att tågen är tillgängliga när de är planerade att användas. För att hålla tågen i drift behöver de underhållas. Oplanerade stopp på grund av driftstörningar och fel kostar både pengar och tid för operatören. Utöver det påverkar ett stillastående tåg även resterande tåg som trafikerar spåren.

    Med detta examensarbete är målsättningen att förbättra det förebyggande underhållet för traktionsmotor liknande MSG-3 analysen för flygplan. Målet är att säkerställa rätt innehåll i underhållsprogrammet för att hindra oplanerade stopp. Avsikten med MSG-3 metoden är, förutom att få fram alla schedulerade underhållsåtgärder och intervall som skall till för att behålla och återställa detaljens inbyggda tillförlitlighetsnivåer, att få fram information som är nödvändig för konstruktionsförbättringar där det visar sig att konstruktionen inte håller måttet.

  • 94.
    Berggren, Daniel
    KTH, Tidigare Institutioner, Flygteknik.
    Investigation of limit cycle oscillations for a wing section with nonlinear stiffness2004Ingår i: Aerospace Science and Technology, ISSN 1270-9638, E-ISSN 1626-3219, Vol. 8, nr 1, s. 27-34Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A wind tunnel experiment is designed with the objective to obtain well-behaved limit cycle oscillations for a wing section with two degrees of freedom, translation and rotation, in two-dimensional flow. This is accomplished using a setup of linear springs so that the resulting moment is a nonlinear function of the rotation angle. The experimental setup is designed so that the amplitudes of the limit cycle oscillations are sufficiently low to motivate the use of linear aerodynamics in the analysis. The experimental results are compared to analyses for two different configurations, and the agreement is fairly good.

  • 95.
    Berglund, Martin
    et al.
    Uppsala University.
    Sturesson, Peter
    Försvarshögskolan, Militärvetenskapliga institutionen (MVI), Militärtekniska avdelningen (MTA). Uppsala University.
    Persson, Anders
    Uppsala University.
    Thornell, Greger
    Uppsala University.
    Manufacturing Miniature Langmuir probes by Fusing Platinum Bond Wires2015Ingår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, nr 10, artikel-id 105012Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper reports on a novel method for manufacturing microscopic Langmuir probes with spherical tips from platinum bond wires by fusing for plasma characterization in microplasma sources. Here, the resulting endpoints, formed by droplets on the ends of a fused wire, are intended to act as spherical Langmuir probes. For studying the fusing behavior, bond wires were wedge bonded over a 2 mm wide slit, to emulate the final application, and fused with different voltages and currents. For electrical isolation, a set of wires were coated with a 4 μm thick layer of Parylene before they were fused. After fusing, the gap size, as well as the shape and area of the ends of the remaining stubs were measured. The yield of the process was also investigated, and the fusing event was studied using a high-speed camera for analyzing its dynamics. Four characteristic tip shapes were observed: spherical, folded, serpentine shaped and semi-spherical. The stub length leveled out at  ~400 μm as the fusing power increased. The fusing of the coated wires required a higher power to yield a spherical shape. Finally, a Parylene coated bond wire was integrated into a stripline split-ring resonator (SSRR) microplasma source, and was fused to form two Langmuir probes with spherical endpoints. These probes were used for measuring the IV characteristics of a plasma generated by the SSRR. In a voltage range between  −60 V and 60 V, the fused stubs exhibited the expected behavior of spherical Langmuir probes, and will be considered for further integration.

  • 96.
    Bergman, Caroline
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Bergman, Tobias
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Strukturering av jobbkort: -för ökad effektivitet i underhållsplaneringen2015Studentarbete övrigt, 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Det här Examensarbetet genomfördes i samarbete med Airline Support AB. Airline Support AB är i enlighet med EASA Part 145 en godkänd underhållsorganisation som utför flygplansunderhåll på uppdrag av operatörer och flygplansägare.

     

    Airline Support AB får av kund en arbetsorder som innehåller hundratals jobbkort utan inbördes ordning. Med begränsad tillgång av tekniska hjälpmedel, sorteras dessa jobbkort fysiskt i en lämplig ordning. Sorteringen och prioriteringen av jobbkorten görs genom att man delar in flygplanet i tre zoner och sedan delas de upp mellan de tre arbetslagen som skall genomföra underhållet.

     

    Den fysiska sorteringen av jobbkorten är tidskrävande och måste göras om vid varje tillfälle man åtar sig ett underhållsarbete. Den manuella sorteringen av jobbkorten skapar också dåliga förutsättningar att följa underhållsarbetets gång och kunna ge korrekt status till uppdragsgivaren.

     

    Den huvudsakliga målsättningen med examensarbetet var att få insikt i hur underhållsarbetet inom en Part 145 organisation hanteras i verkligheten. En av målsättningarna var också att finna en bestämd struktur för jobbkorten, sådan att ett dynamiskt system kunde skapas för att automatisera delar av planeringsarbetet.

     

    Examensarbetet genomfördes i samråd och i enlighet med organisationens önskemål. Det bestämdes att man skulle sortera jobbkorten med avseende på hur lång tid varje jobbkort tar att genomföra samt i vilka zoner av flygplanskroppen arbetet skulle utföras. Efter jämförelse mellan olika programvaror så valdes Excel till det bäst lämpade programmet för att skapa den typen av system man önskade.

     

    Ett planeringsverktyg skapades med hjälp av programspråket Visual Basics, efter att man gemensamt kommit överens om önskvärda funktioner. Planeringsverktyget är i huvudsak resultatet av detta examensarbete och omfattas av alla delar av projektets faser.

     

    Det planeringsverktyg som skapades är inte en färdig produkt utan det krävs mera arbete med att få fram exaktare tider för att få systemet att stämma bättre med verkligheten. I och med att man lagt stor vikt på tester och implementering av systemet så har det skapats goda förutsättningar för att verktyget skall uppfylla den huvudsakliga målsättningen att spara resurser och effektivisera underhållsarbetet.

  • 97.
    Bergman, David
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Aerodynamik.
    Study of the coupled interaction between the wake’s transient behavior and pressure surfaces upstream using Detached Eddy Simulation2012Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The aerodynamic sub-discipline of flow control has for many years been, and still is today, a very prominent subject of research. This field encompasses devices that produce a beneficial change in wall-bounded or free shear flows that may lead to, among many possibilities, reduced drag of ground vehicles and airplanes. The end result could have a substantial improved impact on fuel economy and also introduce new possible design options.

    Creo Dynamics AB recently started to venture into the field of active flow control with huge interest for the technology and its possible applications. One such application includes a system that reduces drag on ground vehicles via the use of active flow control. The system is composed of three components: actuators, controller and sensors. The work carried out in this thesis deals with a study into the sensory placement and control approach related to the system on a very conceptual level.

    According to Creo’s vision of the project the sensor shall record the pressure distribution and characteristics up-stream of the actuators. In turn the algorithm shall be capable of translating and correlating this data to the flow state downstream

    and in the wake. This data is then to be relayed to a control system producing the correct actuation response to achieve desired flow characteristics. For this system to work knowledge about the coupling between wake behavior and pressure distribution on surfaces upstream of the separated flow is necessary. This thesis is an initial investigation into the possible couplings that can be found. The scope also includes investigation of the coupling during cross-winds and gusts.

    Simulations of a simplified car geometry were carried out using the CFD package OpenFOAM and the DDES turbulence model. The initial investigation yielded promising results, showing that a link between the wake behavior and pressure distribution up-stream exists. But further work has to be carried out, as is discussed in the last chapter, before the algorithm according to Creo’s specifications can be constructed.

  • 98.
    Berhouni, Ilyès
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Flow transition prediction approaches evaluated on a single-aisle type aircraft2019Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Nuförtiden, eftersom efterfrågan på bränsleeffektivitet ökar och tillverkningstekniker förbättrats för att tillåta utformningen av laminära vingar, de laminära begrepp att återupplivas och studeras och ses som en av de mest lovande teknikerna för att minska ytfriktionen och därmed den totala motståndet hos skrovet. För att förutsäga den typ av fördelar som kan erhållas från sådana begrepp, computational fluid dynamics (CFD) beräkningar kan nu utföras men det är nödvändigt att kunna förutse övergångsflöde från laminär till turbulent runt lyftytorna hos flygplanet , såsom kanterna och det horisontella stjärtplan.

    En sådan förmåga har utvecklats under de senaste åren av den franskaAerospace Laboratory (ONERA) med sin CFD kod Elsa och av den tyska Aerospace Center (DLR) med sin CFD kod Tau. Dessa två koder används allmänt i Airbus i deras CFD kampanjer och denna studie syftar till att bedöma förmågan hos de olika metoder för att förutsäga övergång och fördelarna med laminärt flöde i den totala drag. De metoder som används, de begränsningar och de förslag till ytterligare förbättring av de koder kommer att beskrivas i detalj i detta dokument.

  • 99.
    Bertoni, Alessandro
    et al.
    Luleå University of Technology.
    Isaksson, Ola
    Bertoni, Marco
    Luleå University of Technology.
    Larsson, Tobias
    Luleå University of Technology.
    Assessing the Value of Sub-System Technologies including Life Cycle Alternatives - an aerospace investigation2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Emerging from an industrial case study in the aerospace industry, the paper proposes an approach to evaluate sub- system technology concepts from a life cycle perspective. The approach is composed by 5 main phases that aims to drive product designers towards more value-oriented design decisions. It is shown how different life cycle alternatives, such as the selling of a Product-Service-System instead of a traditional product, deeply impact the value of design alternatives. The described approach has been developed in collaboration with industrial partners and represents a potential instrument to enhance value-driven product design.

  • 100. Bertoni, Marco
    et al.
    Bordegoni, Monica
    Johansson, Christian
    Luleå Technical University.
    Larsson, Tobias
    Luleå Technical University.
    Pilot specifications definition guidelines for the implementation of a KEE solution in the aeronautical domain2008Ingår i: CIRP Design Conference 2008 / [ed] Fred J. A. M. van Houten, Laboratory of Design, Production and Management, Faculty of Engineering Technology, Univ. of Twente , 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    Designing and implementing a Knowledge Management System (KMS) in a Virtual Enterprise is a labour intensive and risky task. Solution prototypes (Pilots) are usually built to verify system effectiveness prior to final implementation. The paper proposes a methodology to guide this Pilot specifications definition process. These guidelines support engineers and knowledge experts in collaboratively defining functionalities, services, software components and performance indicators of the prototype. The methodology has been conceived and applied within the European project VIVACE, to support the development of a Knowledge Enabled Engineering (KEE) system in the aeronautical domain.

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