The aim of the project is to investigate the characteristics and causes of two different types of bow shocks at Mars. We define Type 1 as an undefined, drawn out ramp, and Type 2 as a shorter duration ramp that has clearer characteristics and behaves more like a step increase in the magnetic field. A total of forty five events of the two different types were investigated using data from 2014-2015 from NASA’s MAVEN spacecraft. The Power Spectral Density of the magnetic field is calculated for downstream/ramp/upstream intervals. The normal is calculated with a mixed-mode coplanarity model. Proton, alpha particle and atomic oxygen density are also calculated. Results show higher frequencies for nose events of Type 1, and lower for flank events of Type 1. No such pattern can be seen in Type 2 events. Proton and alpha-particles are shown to be shocked, and their densities are slightly higher at the flanks as compared to the nose of the bow shock. Atomic oxygen density stays constant before and after the bow shock, likely due to the fact that the oxygen originates mostly from the exosphere rather than from the solar wind. Ion densities seem not to be affected by whether the event is Type 1 or 2.

In this thesis I have studied the so-called “Ševčík method” based on the example of his 40 Variations, op. 3. I’ve tried to achieve a deeper understanding of what the exercises are good for and how they work. I took a closer look at Otakar Ševčík’s life and work history, I also investigated other’s opinions and judgements of the “method” that were appearing in press and literature during the last hundred years. The practical part of my project is the experiment that I’ve put myself through. I was diligently practicing 40 Variations every day, trying to improve my technique and learn by playing how to apply those exercises in real life. As a result of this process I’ve developed my bow technique and gained better understanding of how to use Ševčík’s exercises. / <p>The sounding part of the work consists of the following recordings:</p><p>1)Mozart before 2) Mozart after 3) Rossini before 4) Rossini after</p><p>The Corona virus situation spring semester 2020 has caused limitations in the recording possibilities. The recordings may be supplemented. </p>

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When the solar wind encounters a planet’s magnetic field, they interact and the different plasma and magnetic field behaviours divides the magnetosphere into different regions. Two important region boundaries to the outer magnetosphere, called the magnetosheath, are the bow shock and magnetopause. A good deal of knowledge about the planet’s magnetic field can be obtained by studing these boundaries. Moreover, the strength of Jupiter’s magnetic field makes its magnetosheath boundaries an interesting case study. The aim of this study was to compile data covering the crossings of the Jovian bow shock and magnetopause from NASA’s Juno probe and use this data to investigate their shape and location. In doing so, we hoped to be able to assess the validity of previous models and the stability of Jupiter’s magnetic field over time. Both a parabolic curve model and a location distribution function were created as part of this objective. The distribution of boundary crossings prevented fine details in the shape and location of the bow shock and magnetopause from being determined. By analysing the density of occurring boundary crossings it was found that the bow shock and magnetopause are generally positioned closer to Jupiter than determined by previous studies. / Nar solvinden färdas nära en planet växelverkar de. Detta ger upphov till magnetosfären som består av olika områden med varierande plasmabeteenden. Två viktiga gränser till magnetosfärens yttre del, kallad magnetosheath, är bogchocken och magnetopausen. De är intressanta då man vid undersökning kan lära sig mycket om planets magnetfält överlag. Dessutom utgör gränserna av Jupiters magnetosheath en intressant fallstudie på grund av planetens starka magnetfält. Målet med denna studie var att sammanställa data över korsningar av Jupiters bogchock och magnetopause av NASA:s rymdsond Juno for att undersöka deras form och position. Med detta hoppades vi på att kunna bedöma validiteten hos tidigare modeller och bedöma stabiliteten av Jupiters magnetfält över tid. Både en parabolisk modellkurva och en fördelningsfunktion över gränsernas position skapades som en del av detta mål. Fördelningen av gränskorsningar förhindrade bestämmandet av mindre detaljer av form och position hos bogchocken och magnetopausen. Genom att analysera tätheten av förekommande korsningar upptäcktes det att bogchocken och magnetopausen befinner sig i allmänhet närmare Jupiter än vad som bestämts i tidigare studier / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm

Electrons accelerating in shock events occur oftenin outer space, for example in supernovas and the poles of blackholes, and are of high interest to physicists and other researchers.The technology to take a closer look at events that far awaydoes not exist yet, but luckily we can observe similar events inplaces where the Earth’s magnetic fields and particle streamsfrom the Sun meet. Using data from NASA’s MMS mission thispaper aims to gather information about what variables affect theacceleration, under what conditions the most energetic eventsoccur and create a ranked list of several hundreds of theseevents. It did this by calculating the expected value of the electrondistribution function at different times to create a dimensionlessranking. The study showed that these events are highly complexand that it is difficult to assign a few variables which would affectthe acceleration. However it also showed that most accelerationoccurs after the most abrupt shock crossing and not exactly atthe location where the expected value is maximal, and that thereare some correlations with angle relative to the solar magneticfield and electron number density. / Elektroner som accelereras i shockar skerofta i yttre rymden, till exmepel i supernovor och vid polernahos svarta hål, och är därför av högt intresse hos fysikeroch andra forskare. Teknologin för att titta närmre på dessafjärran fenomen existerar inte ännu, men som tur är så kan viobservera liknande händelser på platser där Jordens magnetfältmöter partikelvindar från Solen. Med hjälp av data från NASAsMMS uppdrag har detta projekt önskat att samla informationom vilka variabler som påverkar accelerationen, under vilkaomständigheter de mest energirika händelserna sker och skapa enrankad lista av flera hundra av dessa händelser. Det gjorde dettagenom att beräkna det förväntade värdet på elektronernas distributionsfunktionvid flera tillfällen för att skapa en dimensionslösrank. Studien visade att dessa händelser är mycket komplexaoch att det är svårt att tilldela ett fåtal variabler som skullepåverka accelerationen. Dock så visade projektet att den störstaaccelerationen sker efter den mest abrubta shockkorsningen ochinte exakt vid det tillfälle då det förväntansvärdet är som högst,och att det finns någon korrelation med vinkeln relativt solensmagnetfält och elektronernas nummerdensitet. / Kandidatexjobb i elektroteknik 2021, KTH, Stockholm

Yes / The potentially broad application area in engineering design using Genetic Al- gorithm (GA) has been widely adopted by many researchers due to its high consistency and accuracy. Presented here is the initial design of a wideband non-dispersive wire bow-tie antenna using GA for breast cancer detection applications. The ultimate goal of this design is to achieve minimal late-time ringing but at higher frequencies such as that located from 4 to 8 GHz, in which is desire to penetrate human tissue for near field imaging. Resistively loading method to reduce minimal ringing caused by the antenna internal reflections is implemented and discussed when the antenna is located in free space and surrounded by lossy medium. Results with optimised antenna geometry and di®erent number of resistive loads are presented and compared with and without existence of scatterers.

Numerical simulations of fluid-structure interaction (FSI) problems were performed in an effort to verify and validate a commercially available FSI tool. This tool uses an iterative partitioned coupling scheme between CD-adapco's STAR-CCM+ finite volume fluid solver and Simulia's Abaqus finite element structural solver to simulate the FSI response of a system. Preliminary verification and validation work (VandV) was carried out to understand the numerical behavior of the codes individually and together as a FSI tool. Verification and Validation work that was completed included code order verification of the respective fluid and structural solvers with Couette-Pouiselle flow and Euler-Bernoulli beam theory. These results confirmed the 2nd order accuracy of the spatial discretizations used. Following that, a mixture of solution verifications and model calibrations was performed with the inclusion of the physics models implemented in the solution of the FSI problems. Solution verifications were completed for fluid and structural stand-alone models as well as for the coupled FSI solutions. These results re-confirmed the spatial order of accuracy but for more complex flows and physics models as well as the order of accuracy of the temporal discretizations. In lieu of a good material definition, model calibration is performed to reproduce the experimental results. This work used model calibration for both instances of hyperelastic materials which were presented in the literature as validation cases because these materials were defined as linear elastic. Calibrated, three dimensional models of the bow seal on the University of Michigan bow seal test platform showed the ability to reproduce the experimental results qualitatively through averaging of the forces and seal displacements. These simulations represent the only current 3D results for this case. One significant result of this study is the ability to visualize the flow around the seal and to directly measure the seal resistances at varying cushion pressures, seal immersions, forward speeds, and different seal materials. SES design analysis could greatly benefit from the inclusion of flexible seals in simulations, and this work is a positive step in that direction. In future work, the inclusion of more complex seal geometries and contact will further enhance the capability of this tool. / Ph. D.

A stator cascade was developed to simulate the flow conditions within a close-stage-spacing transonic axial compressor. Experiments were conducted in a linear transonic blowdown cascade wind tunnel with an inlet Mach number of 0.65. The bow shock from the downstream rotor was simulated by a single moving normal shock generated with a shock tube. First, steady pressure data were gathered to ensure that the stator cascade operated properly without the presence of the shock. Next, the effects of the passing shock on the stator flow field were investigated using shadowgraph photography and Digital Particle Image Velocimetry (DPIV). Measurements were taken for three different shock strengths. In every case studied, a vortex formed near the stator trailing edge as the shock impacted the blade. The size of this vortex was shown to be directly related to the shock strength, and the vortex remained present in the trailing edge flow field throughout the cycle duration. Analysis of the DPIV data showed that the vortex acts as a flow blockage, with the extent of this blockage ranging from 2.9% of the passage for the weakest shock, to 14.3% of the passage for the strongest shock. The vortex was also shown to cause flow deviation up to 75° for the case with the strongest shock. Further analysis estimated that the total pressure losses due to shock-induced vorticity ranged from 46% to 113% of the steady wake losses. Finally, the total pressure loss purely due to the upstream-propagating normal shock was estimated to be roughly 0.22%. / Master of Science

This paper addresses the problem of mobile robot localization based on current 2D and 3D data and previous records. Focusing on practical loop detection in the trajectory of a robot. The objective of this work was to evaluate current methods of image processing and depth data for issues of localization in environment. This work uses Bag of Words for 2D data and environment of point cloud with Viewpoint Feature Histogram for 3D data. Designed system was implemented and evaluated.